The following agenda was added or modified on 2022-01-13 11:34:44 by npierce@grotonma.gov.

Date: Jan 20, 2021 at 7:00 PM

Location: Zoom Meeting  -  https://us02web.zoom.us/j/89524981665?pwd =MjlQbW4zYlBaemhXRXVVQjREbHlaZz09

Meeting ID: 895 2498 1665
Passcode: 320894

       +1 929 205 6099 US (New York)

 

7:00 Call to order

7:00 Review of Geosynthec Report and discussion of path forward

 

8:00 Meeting minutes – Review, any updates and vote to the approval of previous minutes

 

8:05 Financial Summary

 

8:15 Duck Pond

 

8:25 Lost Lake / Knops Pond

- Treatment funding

 

8:35 Baddacook Pond

         

8:45 Whitney Pond

 

7:55 Adjourn

 

* Vote may be taken

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.

 

 

 

 

 

 

 

The following agenda was added or modified on 2022-01-13 11:33:25 by npierce@grotonma.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Town of Groton, MA

in coordination with

Groton Lakes Association

and the

Great Pond Advisory Committee

 

Cover Photo: Lost Lake Boat Ramp Photo Credit: Geosyntec Consultants, Inc.

 

Acknowledgements

The purpose of a Massachusetts Watershed-Based Plan (WBP) is to organize information about Massachusetts' watersheds and present the information in a format that will enhance the development and implementation of projects to restore water quality and beneficial uses in the Commonwealth. The Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was developed by Geosyntec under the direction of Alex Woodle with funding, input, and collaboration from Groton Lakes Association (GLA) and Great Ponds Advisory Committee (GPAC). This WBP was developed using funds from the Community Preservation Act (CPA) and using the Massachusetts Department of Environmental Protection’s (MassDEP’s) Watershed-Based Planning Tool (WBP Tool).

GLA has a goal of preserving and improving the lakes in eastern Groton, including Lost Lake/ Knops Pond. GLA conducts a variety of volunteer events and has been involved with removal of invasive plants and weeds in the lake.

As a nine-member committee in the Town of Groton, GPAC members work on weed management in the lake and make recommendations to the Select Board. Like the GLA, they deal with issues relating to lake management, including health, safety, water quality, and environmental protection.

The following individuals and organizations have contributed invaluable assistance and support for this project:

Core Stakeholders

Alexander Woodle, member of GPAC and GLA

GPAC

GLA

Grotonwood Camp

Gibbet Hill/Weber Restaurant Group

Groton Country Club

Tom Delaney – Director of Public Works (Groton)

 

Project Team

Alexander Woodle, GPAC, GLA

Adam Questad, PE, Geosyntec Consultants, Inc.

Renee Bourdeau, PE, Geosyntec Consultants, Inc.

Julia Keay, PE, Geosyntec Consultants, Inc.

Emma Williamson, EIT, Geosyntec Consultants, Inc.

 

 

Table of Contents

 

Acknowledgements. i

List of Tables. iv

List of Figures. v

Acronyms and Abbreviations. vi

Watershed-Based Plan Background. 1

Incorporating USEPA’s Nine Elements. 1

1.0         Introduction. 3

1.1 Data Sources. 3

1.2 Goal Statement 3

1.3 Plan Development Process. 4

2.0         Characteristics of Lost Lake and Knops Pond. 4

2.1 Land Use. 7

2.2 Impervious Cover 9

3.0         Assessment of Water Quality. 11

3.1 Water Quality Impairments. 11

3.2 Water Quality Goals. 12

3.3 TMDL Pollutant Load Criteria. 14

4.0         Water Quality Summary (Element A) 14

4.1 Additional Water Quality Information. 14

5.0         Water Quality Goals for Lost Lake and Knops Pond (Element B) 35

5.1 Estimated Pollutant Loads. 35

5.2 Water Quality Goals. 37

6.0         Management Actions to Control Phosphorus (Elements C, D, and E) 39

6.1 BMP Hotspot Map. 41

6.2 Field Watershed Investigation. 45

6.3 Existing Management Measures. 48

6.4 Watershed-Wide BMPs. 48

6.5 Site-Specific BMPs. 51

6.6 Non-Structural BMPs and Watershed Outreach (Category 5) 53

7.0         Schedule and Milestones (Elements F and G) 54

8.0         Success Indicators and Evaluation (Element H) 56

9.0 Monitoring Plan (Element I) 57

10.0      Funding for Future Watershed Planning Phases and Implementation. 60

10.1 Cost Estimate and Pollutant Load Reduction Estimates. 60

10.2 Funding for Proposed Management Measures. 61

11.0      Conclusions. 63

12.0      References. 64

Appendix A – Pollutant Load Export Rates (PLERs) 68

Appendix B – Conceptual Design Sheets. 70

 

 

 

 

List of Tables

Table 1: USEPA’s Nine Elements of Watershed Planning

Table 2-1: General Watershed Information

Table 2-2: Watershed Land Uses

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Table 3-3: Surface Water Quality Classification by Assessment Unit

Table 3-4: Water Quality Goals

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion

Table 4-2: Dry Weather Water Quality Parameters

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites

Table 4-5: Groundwater Nutrient Analysis

Table 4-6: Water Quality Data

Table 4-7: Tributary Water Quality Data

Table 4-8: Well Water Quality Data

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants

Table 5-2: Pollutant Load Reductions Needed

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis

Table 6-2: Slope Stabilization Cost Estimates

Table 6-3: Non-Structural BMPs

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs

Table 10-2: Proposed Structural BMP Priority Matrix

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan

 

 

List of Figures

Figure 2-1: Watershed Boundary Map

Figure 2-2: Watershed Land Use Map

Figure 2-3: Watershed Impervious Surface Map

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations

Figure 4-2: Erosion and Point Source Sampling Locations

Figure 4-3: Groundwater Seepage Sampling Locations

Figure 4-4: Sampling Locations

Figure 4-5: Pore Water Nitrate Concentrations

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations

Figure 4-7: Deep Hole Phosphorus Levels

Figure 4-8: Deep Hole Dissolved Oxygen Levels

Figure 4-9: Deep Hole Chlorophyll-a Levels

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation

Figure 4-11: Tributary Phosphorus Concentrations

Figure 4-12: Sampling Stations

Figure 4-13: Photos from GLA Presentation

Figure 6-1: Proposed BMP Locations

Figure 6-2: BMP Hotspot Map

Figure 6-3: Erosion Off Paved Roads

Figure 6-4: Erosion on Unpaved Roads

Figure 6-5: Typical Ditch Detail

Figure 6-6: Catch Basin Filtration Inlet System

Figure 9-1: Proposed Monitoring Locations

 

 

 

Acronyms and Abbreviations

AACE	Association for the Advancement of Cost Engineering
BMP	Best Management Practice
°C	Celsius
CEI	Comprehensive Environmental, Inc.
cells/mL	cells per milliliter
CPI	Consumer Price Index
DCIA	Directly Connected Impervious Areas
DO	Dissolved Oxygen
USEPA	United States Environmental Protection Agency
ET	Evapotranspiration
FC	Fecal Coliform
FS	Fecal Streptococci
GIS	Geographic Information System
GLA	Groton Lakes Association
GPAC	Great Ponds Advisory Committee
lbs.	pounds
lbs./acre/yr.	pounds per acre per year
lbs./yr.	pounds per year
MassDEP	Massachusetts Department of Environmental Protection
mg/L	milligrams per liter
µg/L	microgram per liter
ml	milliliter
NPS	Nonpoint Source
NRCS	National Resource Conservation Service
O&M	Operation and Maintenance
P	precipitation
PLER	Pollutant Load Export Rate
ppb	parts per billion
QAPP	Quality Assurance Project Plan
QA/QC	Quality Assurance / Quality Control
R	Runoff Depth
TIA	Total Impervious Area
TKN	Total Kjeldahl Nitrogen
TMDL	Total Maximum Daily Load
TN	Total Nitrogen
tons/year	tons per year
TP	Total Phosphorus
TSS	Total Suspended Solids
USDA	U.S. Department of Agriculture
USGS	U.S. Geological Survey
WBP	Watershed-Based Plan

 

Watershed-Based Plan Background

A Massachusetts Watershed-Based Plan (WBP) organizes information about a Massachusetts watershed and presents the information in a format that supports the development and implementation of projects to restore water quality and beneficial uses. A Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was prepared for the Lost Lake/Knops Pond watershed in the town of Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). There are two main tributaries: Martins Pond Brook and an Unnamed Tributary.

Incorporating USEPA’s Nine Elements

The Lost Lake/Knops Pond Watershed-Based Plan includes nine criteria[1] for restoring waters impaired by nonpoint source (NPS) pollution. In this plan, the criteria will be called Elements A through I. These guidelines set forth by USEPA, highlight important steps in protecting water quality for waterbodies impacted by human activities and include specific recommendations for guiding future development, as well as strategies for reducing the cumulative impacts of NPS pollution on water quality. The nine criteria are as follows:

1. Identify causes and sources of pollution: The plan must identify the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated herein (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in Element B immediately below. Sources that need to be controlled should be identified at the significant subcategory level with estimates of the extent to which they are present in the watershed (e.g., X numbers of dairy cattle feedlots needing upgrading, including a rough estimate of the number of cattle per facility; Y acres of row crops needing improved nutrient management or sediment control; or Z linear miles of eroded stream bank needing remediation).
2. Estimate pollutant loading into the watershed and the expected load reductions: The plan must estimate the load reductions expected for the management measures described under Element C below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time). Estimates should be provided at the same level as in Element A above (e.g., the total load reduction expected for dairy cattle feedlots; row crops; or eroded stream banks).
3. Describe management measures that will achieve load reductions and targeted critical areas: The plan must describe the NPS management measures that will be implemented to achieve the load reductions estimated under Element B above (as well as to achieve other watershed goals identified in this watershed-based plan), and an identification, using a map or a description, of the critical areas in which those measures will be needed to implement this plan.
4. Estimate amounts of technical and financial assistance and the relevant authorities needed to implement the plan: The plan must contain estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, for implementation. As sources of funding, states should consider Section 319 programs, State Revolving Funds, USDA’s Environmental Quality Incentives Program and Conservation Reserve Program, and other relevant federal, state, local, and private funds.
5. Develop an information/education component: An information/education component will enhance public understanding of the project and encourage early and continued public participation in selecting, designing, and implementing the NPS management measures.
6. Develop a project schedule: A schedule for implementing the NPS management measures identified in this plan will be established.
7. Describe the interim, measurable milestones: The plan will set forth interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented.
8. Identify indicators to measure progress: The plan will include set of criteria to determine whether loading reductions are being achieved over time and whether substantial progress is being made towards attaining water quality standards. In the case that reductions are not achieved, or progress is not made, criteria will also be established for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised.
9. Develop a monitoring component: A monitoring component will evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under Element H immediately above.

The primary goal of this WBP is to assess the Lost Lake/Knops Pond watershed and provide a plan for implementing actions that will result in measurable improvements in water quality. To achieve this goal, this WBP was developed to include the following nine elements in conformance with USEPA guidance discussed above.

Table 1: USEPA’s Nine Elements of Watershed Planning

Element	Plan Section	Element Description
A	4.0	Identify causes and sources of pollution
B	5.0	Estimate pollution load reductions needed for restoration
C	6.0	Identify actions needed to reduce pollution
D	6.0	Estimate costs and authority to implement restoration actions
E	6.0	Implement outreach and education to support restoration
F	7.0	Restoration schedule
G	7.0	Milestones—interim measures to show implementation progress
H	8.0	Success indicators and evaluation—criteria to show restoration success
I	9.0	Monitoring plan

 

1.0       Introduction

The Lost Lake/Knops Pond WBP describes water quality conditions, watershed characteristics, and sources of phosphorus loading to Lost Lake/Knops Pond. The WBP also establishes water quality goals, proposes best management practices (BMPs) for reducing nutrient loading, and estimates associated costs.

The overall goals of the Lost Lakes/Knops Pond WBP are as follows:

• Identify and quantify sources of nutrient loading to the lake
• Establish water quality goal(s) for the watershed
• Propose BMPs to reduce nutrient loading

The adaptive management approach described in the plan allows project partners flexibility in implementing BMPs. Additionally, the plan recognizes that improvements in water quality cannot be achieved with a single BMP and that results are typically not immediate. The proposed water quality monitoring will help guide the approach and quantify the impacts of implemented BMPs.

1.1 Data Sources

This WBP was developed using data sources provided by the Massachusetts Department of Environmental Protection (MassDEP). Additional data sources were reviewed and are described in subsequent sections of this WBP and listed below:

• Lost Lake Watershed Management Plan (ESS Group Inc. 2017)
• Aquatic Vegetation Program 2017 Annual Report, Solitude Lake Management (Solitude 2017)
• Lost Lake Water Quality Investigation Report, Comprehensive Environmental, Inc. (CEI 2013)
• A Diagnostic/Feasibility Study for the Management of Lost Lake/ Knopps [sic] Pond (Baystate Environmental Engineers 1989)
• Lost Lake/Knops Pond Resources Management Plan (GLA 2012)
• Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

1.2 Goal Statement

The long-term goal of this WBP is to reduce total phosphorus (TP) and other nutrient and sediment loadings to Lost Lake/Knops Pond. These pollutant load reductions may result in improvements to water quality conditions in Lost Lake/Knops Pond, as well as reducing the occurrence of eutrophication.

This goal will be accomplished primarily through installation of BMPs to capture runoff while reducing erosion and related nutrient and sediment loading to Lost Lake/Knops Pond from areas near the lake and from its two main tributaries. BMPs are proposed at multiple locations throughout the watershed.

1.3 Plan Development Process

This WBP was developed through collaboration during project management team meetings and conference calls primarily between Geosyntec, Alexander Woodle, and other members of GPAC and GLA.

An iterative process was used to develop the WBP, as outlined below:

• The Project Team (from Geosyntec Consultants, Inc.) first collected and reviewed existing data from the GLA and the GPAC and other available sources.
• A meeting was held on August 12, 2021 to solicit input and information about the Lost Lake/Knops Pond watershed and to identify possible sources of pollution, existing BMP projects, potential BMP opportunity locations, water quality goals, and public outreach activities.
• The Project Team then visited the site on August 30, 2021 to gather data on problem areas and potential BMP opportunity sites.
• A meeting was held on October 21, 2021 to update stakeholders regarding the site visit and to solicit feedback on proposed strategies to improve the water quality within the watershed.
• A WBP was drafted and reviewed by GPAC and GLA.
• The WBP was finalized based on GPAC and GLA input.

2.0       Characteristics of Lost Lake and Knops Pond

This WBP was prepared for the Lost Lake/Knops Pond watershed, in Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). The watershed is mostly forested, with low density residential areas near the lake and agricultural land use in the northwest portion of the watershed. Historically, the land use in the watershed was predominantly agricultural, especially in the northwestern part of the watershed near Martins Brook Pond. Now, activities in the watershed are mostly recreational (e.g., boating, swimming, and fishing on the lake) and agricultural (small farms in the northwest part of the watershed).

Lost Lake and Knops Pond, collectively referred to as Lost Lake/Knops Pond is one water body with two parts. The Lost Lake is the northern section and Knops Pond is the southern section. They join at the area between Ridgewood Road and Radio Road.

There are two main inlets to the lake: Martins Brook that discharges from Martins Brook Pond into the north of the lake and a shorter unnamed tributary that discharges into the west side of the lake. The lake discharges into Whitney Pond to the northeast.

Table 2-1 presents the general watershed information for the Lost Lake/Knops Pond watershed[2] and Figure 2-1 includes a map of the watershed boundary (Mass Geographic Information Systems (GIS) 2001).

Table 2-1: General Watershed Information

Watershed Name (Assessment Unit ID):	Lost Lake/Knops Pond (MA84084)
Major Basin:	Merrimack
Watershed Area:	3,099.3 acres
Water Body Size:	186 acres

Figure 2-1: Watershed Boundary Map[3]

Ctrl + Click on the map to view a full-sized image in your web browser

 

2.1 Land Use

Land use in the Lost Lake/Knops Pond watershed is mostly forested and accounts for approximately 65 percent (%) of the watershed; approximately 12% of the watershed is low density residential; approximately 9% of the watershed is water; approximately 7% of the watershed is agriculture; approximately 4% of the watershed is open land; approximately 2% of the watershed is high density residential; approximately 1% of the watershed is medium density residential; less than 1% of the watershed is commercial or industrial; and 0% of the watershed is designated as highway (Table 2-2; Figure 2-2). Roadways are included in the residential percentages.

A large portion of the residential area is located around Lost Lake/Knops Pond. The area is mostly low density residential, with more developed areas to the northeast of the lake, off Lost Lake Drive. There is a large, forested area north of the lake and agricultural areas (small farms, including cattle and horse farms) in the northwest portion of the watershed.

Table 2-2: Watershed Land Uses

Land Use	Area (acres)	Percent of Watershed
Forest	2,010	64.9
Low Density Residential	383	12.3
Water	285	9.2
Agriculture	204	6.6
Open Land	113	3.6
High Density Residential	51	1.7
Medium Density Residential	31	1.0
Commercial	22	0.7
Highway	0	0.0
Industrial	0	0.0

 

Figure 2-2: Watershed Land Use Map[4]

Ctrl + Click on the map to view a full-sized image in your web browser

2.2 Impervious Cover

There is a strong link between impervious land cover and stream water quality. Impervious cover includes surfaces that prevent the infiltration of water into the ground, such as paved roads and parking lots, roofs, and basketball courts. Most of the impervious cover in the watershed is associated with roads (Figure 2-3).

Impervious areas that are directly connected (DCIA) to receiving waters (via storm sewers, gutters, or other impervious drainage pathways) produce higher runoff volumes and transport stormwater pollutants with greater efficiency than disconnected impervious areas, which are surrounded by vegetated, pervious land. Runoff from disconnected impervious areas is reduced as stormwater flows across adjacent pervious surfaces and infiltrates.

Estimated DCIA for the watershed was calculated using Sutherland equations. USEPA provides guidance (USEPA 2010) on the use of these equations to predict relative levels of connection and disconnection based on the type of stormwater infrastructure within the total impervious area (TIA) of a watershed. Within each subwatershed, the total area of each land use was summed and used to calculate the percent TIA. The estimated TIA and DCIA for the Lost Lake/Knops Pond watershed is 5.7% and 3.6%, respectively.

Although the estimated TIA in the Lost Lake/Knops Pond watershed falls in the 0% and 10% range that typically denotes high quality, this estimation does not account for erosion on unpaved roads or on the slopes of paved roads, that has led to pollution within the lake. The relationship between TIA and water quality can generally be categorized as shown in Table 2-3 (Schueler et al. 2009):

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality (Schueler et al. 2009)

Percent Watershed Impervious Cover	Stream Water Quality
0–10	Typically, high quality, and typified by stable channels, excellent habitat structure, good to excellent water quality, and diverse communities of fish and aquatic insects.
11–25	Clear signs of degradation. Elevated storm flows begin to alter stream geometry, with evident erosion and channel widening. Stream banks become unstable, and physical stream habitat is degraded. Stream water quality shifts into the fair/good category during storms and dry weather. Stream biodiversity declines to fair levels, with most sensitive fish and aquatic insects disappearing from the stream.
26–60	Typically, no longer supportive of a diverse stream community. The stream channel becomes highly unstable, and many stream reaches experience severe widening, downcutting, and streambank erosion. Pool and riffle structure needed to sustain fish is diminished or eliminated and the substrate no longer provides habitat for aquatic insects or spawning areas for fish. Biological quality is typically poor, dominated by pollution tolerant insects and fish. Water quality is consistently fair to poor, and water recreation is often no longer possible due to high bacteria levels.
>60	These streams are typical of “urban drainage,” with most ecological functions greatly impaired or absent, and the stream channel primarily functioning as a conveyance for stormwater flows.

 

Figure 2-3: Watershed Impervious Surface Map[5]

Ctrl + Click on the map to view a full-sized image in your web browser

3.0       Assessment of Water Quality

The goals of this WBP are founded upon the State’s water quality goals and criteria, which specify the indicators by which water quality improvements are measured. This section is an overview of the standards and criteria that apply to Lost Lake/Knops Pond.

3.1 Water Quality Impairments

Known water quality impairments are documented in MassDEP’s 2016 Massachusetts Integrated List of Waters (MassDEP 2019). The impairment categories from this document are set forth in Table 3-1, and water quality impairments are listed in Table 3-2.

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Integrated List Category	Description
1	Unimpaired and not threatened for all designated uses
2	Unimpaired for some uses and not assessed for others
3	Insufficient information to make assessments for any uses
4	Impaired or threatened for one or more uses, but not requiring calculation of a Total Maximum Daily Load (TMDL), including: 4A: TMDL is completed 4B: Impairment controlled by alternative pollution control requirements 4C: Impairment not caused by a pollutant—TMDL not required
5	Impaired or threatened for one or more uses and requiring preparation of a TMDL

 

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Assessment Unit ID	Waterbody	Integrated List Category	Designated Use	Impairment Cause	Impairment Source
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Atmospheric Deposition—Toxics
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Source Unknown
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Eurasian Water Milfoil, Myriophyllum spicatum[6]	Introduction of Nonnative Organisms (Accidental or Intentional)
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Nonnative Aquatic Plants[7]	Introduction of Nonnative Organisms (Accidental or Intentional)

 

3.2 Water Quality Goals

Water quality goals may be established for many purposes, including the following:

1. Forwater bodies with known impairments, aTotal Maximum Daily Load (TMDL) is established by MassDEP and USEPA as the maximum amount of the target pollutant that the waterbody can receive and still safely meet water quality standards. If the waterbody has a TMDL for total phosphorus (TP), total nitrogen (TN), or total suspended solids (TSS), that information is provided below and included as a water quality goal.
2. Forwater bodies without a TMDL for TP, a default water quality goal for TP is based on target concentrations established in theQuality Criteria for Water (USEPA 1986; also known as the “Gold Book”). The Gold Book states that TP should not exceed 50 micrograms per liter (µg/L) in any stream at the point where it enters any lake or reservoir, nor 25 µg/L within a lake or reservoir. For the purposes of developing WBPs, MassDEP has adopted a TP target of 50 µg/L for all streams at their downstream discharge point, regardless of which type of water body the stream discharges to.
3. Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013) prescribe the minimum water quality criteria required to sustain a waterbody’s designated uses. Lost Lake/Knops Pond is a Class B waterbody. The water quality goal for fecal coliform bacteria is based on the Massachusetts Surface Water Quality Standards.

Table 3-3: Surface Water Quality Classification by Assessment Unit

Assessment Unit ID	Waterbody	Class
MA84084	Lost Lake/Knops Pond	B

 

1. Other water quality goals set by the community(e.g., protection of high-quality waters, in-lake phosphorus concentration goal to reduce recurrence of cyanobacteria blooms).

Table 3-4 shows the pollutant and associated water quality goals. For TP, there is no Nonnative Aquatic Plants TMDL for Lost Lake/Knops Pond (although there is a Mercury in Fish Tissue TMDL); therefore, we are using standards from the Gold Book as described in part b above.

Table 3-4: Water Quality Goals

Pollutant

Goal

Source

Total Phosphorus (TP)	Total phosphorus should not exceed: 50 µg/L in any stream 25 µg/L within any lake or reservoir	Quality Criteria for Water (USEPA 1986)
Bacteria	Class B Standards • Public Bathing Beaches: For E. coli, geometric mean of five most recent samples shall not exceed 126 colonies/100 ml and no single sample during the bathing season shall exceed 235 colonies/100 ml. For enterococci, geometric mean of five most recent samples shall not exceed 33 colonies/100 ml and no single sample during bathing season shall exceed 61 colonies/100 ml. • Other Waters and Nonbathing Season at Bathing Beaches: For E. coli, geometric mean of samples from most recent six months shall not exceed 126 colonies/100 ml (typically based on min. 5 samples) and no single sample shall exceed 235 colonies/100 ml. For enterococci, geometric mean of samples from most recent 6 months shall not exceed 33 colonies/100 ml, and no single sample shall exceed 61 colonies/100 ml.	Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013)

Note: There may be more than one water quality goal for bacteria due to different Massachusetts Surface Water Quality Standards Classes for different Assessment Units within the watershed.

The section below summarizes the findings from the Water Quality Assessment Reports that relate to water quality and impairments. Select excerpts from these documents relating to the water quality in the watershed are included below. (Note that relevant information is included directly from these documents for informational purposes and has not been modified.)

Merrimack River Watershed 2004 Water Quality Assessment Report (MA84084 - Lost Lake/Knops Pond)

Four non-native aquatic plant species (Trapa natans, Myriophyllum spicatum, Cabomba caroliniana, Potamogeton crispus) have been reported in Lost Lake/Knops Pond. The Aquatic Life Use is assessed as impaired based on the presence of non-native aquatic plants. Cause(s) of Impairment: Non-Native Aquatic Plants, Eurasian Water Milfoil (Myriophyllum spicatum) Source(s) of Impairment: Introduction of Non-Native Organisms MassDEP DWM biologists collected fish from the pond in May 2004 and composite samples of edible fillets were analyzed for As, Cd, Hg, Pb, Se, PCBs and organochlorine pesticides. MA DPH has issued a fish consumption advisory due to mercury contamination for Lost Lake/Knops Pond. Children younger than 12 years of age, pregnant women, women of childbearing age who may become pregnant, and nursing mothers should not eat any Largemouth Bass fish from this water body. The public should limit consumption of Largemouth Bass fish to two meals per month. Cause(s) of Impairment: Mercury in Fish Tissue Source(s) of Impairment: Atmospheric Deposition - Toxics, Source Unknown Insufficient data were available to assess the Primary Contact Recreational Use. Insufficient data were available to assess the Secondary Contact Recreational Use. Insufficient data were available to assess the Aesthetics Use. Report Recommendations: Conduct monitoring to confirm the presence of non-native aquatic plants.

 

3.3 TMDL Pollutant Load Criteria

Due to the Mercury in Fish Tissue impairment, Lost Lake/Knops Pond is subject to a Regional Mercury TMDL, linked below.

• Northeast Regional Mercury Total Maximum Daily Load

The Lost Lake/Knops Pond watershed does not have a TMDL for non-native plants. MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for the Eurasian Water Milfoil (Myriophyllum spicatum) and Non-Native Aquatic Plants impairments as the impairments are nonpollutants (MassDEP 2019).

4.0       Water Quality Summary (Element A)

In addition to the water quality data discussed in Section 3, above, multiple studies have been conducted for Lost Lake/Knops Pond. Additionally, multiple methods to control invasive plant growth have been implemented, including those described in the 2012 Lost Lake/Knops Pond Resources Management Plan (GLA 2012) and the 2017 Aquatic Vegetation Management Program Annual Report for Lost Lake/Knops Pond (Solitude 2017). A detailed timeline of invasive aquatic plant control methods used is included in Section 6.  

4.1 Additional Water Quality Information

Additional water quality data and information collected from the Knops Pond/Lost Lake watershed from 1988 through 2017 is described below (ESS Group 2017, CEI, Inc. 2013, Baystate Environmental Engineers 1989, GLA 2014).

4.1.1 Lost Lake Watershed Management Plan (ESS Group, Inc. 2017)

This report describes pollutant and nutrient levels from natural and manmade sources in the Lost Lake/Knops Pond watershed. Results and conclusions from the report are summarized below:

• Sampling Locations. The sampling locations for TSS and point sources, other water quality parameters, and sediment are shown in Figure 4-1. The sampling locations for erosion (stormwater runoff) and point sources are shown in Figure 4-2. The groundwater seepage sampling locations are shown in Figure 4-3.
• Sampling Dates. Sampling was conducted on September 9, October 6, and November 16, 2016.
• Sediment Loading. Six locations were sampled for sediment loading (inlets, outlet, and three sites experiencing erosion), and the results are shown in Table 4-1. Parameters sampled included TSS, pH, specific conductance, salinity, temperature, dissolved oxygen (DO), and turbidity. The report found relatively high TSS levels at the locations experiencing erosion (170, 47, and 100 mg/L at TP-2, TP-3, and TP-4, respectively) compared to the low levels at the outlet (<5.0 milligrams per liter [mg/L]). These findings indicate that sediment settles in the lake and does not exit at the outlet. Additionally, the report states the low TSS values observed at the inlets to the lake (6 and <5.0 mg/L respectively for Inlet 1 and Inlet 2) indicated the sediment settles out before entering the lake.
• Dry Weather Sampling. Seven locations (inlets, outlet, and surface and bottom of both sides of Lost Lake/Knops Pond) were sampled for TP, dissolved phosphorus, nitrite-N, nitrate-N, total Kjeldahl nitrogen (TKN), total nitrogen, and TSS during dry weather. The results of this effort are shown in Table 4-2. The report indicated relatively high concentrations of phosphorus at the inlets (compared to the surface and bottom of Lost Lake/Knops Pond), suggesting large phosphorus sources from within the watershed. The report also stated that low DO concentrations indicated the presence of increased organics, decomposition, and algal growth and subsequent decay that may have been caused by excessive nutrients. The low DO concentrations can also create conditions that are favorable for release of sediment-bound phosphorus in the lake sediment, depending on how the phosphorus is bound.
• Water Profiles at Deepest Locations. Water profiles were collected at the deepest locations in Lost Lake/Knops Pond (Table 4-3). The report stated that water quality profiles indicate that water below 1.5 meters was not capable of supporting a healthy fish community in Lost Lake (the northern portions of Lost Lake/Knops Pond); however, the DO concentrations were suitable in Knops Pond (the southern portions of the waterbody).
• Wet Weather Sampling. The wet weather point source and erosion sampling (stormwater runoff at locations experiencing erosion) results from six stormwater samples are shown in Table 4-4. Water quality data includes TP, dissolved phosphorus, nitrate-N, TKN, flow, TSS, pH, specific conductivity, salinity, temperature, DO, and turbidity results at the inlets, outlet, and four locations experiencing erosion. The report stated that data from the roadway stormwater runoff indicated that shoreline erosion is occurring and that sediments containing nutrients are subsequently entering the lake. The high nutrient load in the sediments is indicated by the high phosphorus concentrations measured at the erosional sites. The report also stated the specific conductivity results indicated the sand and sediment are of more concern to water quality than road de-icing agents, although this may change seasonally.
• Groundwater Sampling. Lastly, groundwater nutrient concentrations and rate of seepage are shown in Table 4-5. The report stated that these results indicated that groundwater is entering the lake and that it may also contain nutrients, including dissolved phosphorus. Depending on the installation process of the seepage meters, the nutrients measured may be from the sediments rather than the groundwater itself.
• The measured TSS and concentrations of phosphorus at the sites experiencing erosion and inlets during sediment loading sampling, dry weather sampling, and wet weather sampling indicate that erosion, and specifically the associated phosphorus load, are a significant source of phosphorus to the lake and are most likely a contributor of nutrient issues and decreased water quality within the lake.

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations (ESS, 2017).

 

Figure 4-2: Erosion and Point Source Sampling Locations (ESS 2017).

Figure 4-3: Groundwater Seepage Sampling Locations (ESS 2017).

 

 

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion (ESS 2017).

Note: mg/L is milligrams per liter; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is part per trillion; C is degrees Celsius; % is percent; mg/L is milligrams per liter; NTU is nephelometric turbidity units.

Table 4-2: Dry Weather Water Quality Parameters (ESS 2017).

Note: SU is standard unit; NTU is nephelometric turbidity units; % is percent, mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius; CFS is cubic feet per second.

 

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond (ESS 2017).

 

Note: m is meters; % is percent; mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius.

 

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites (ESS 2017).

Note: mg/L is milligrams per liter, CFS is cubic feet per second; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is parts per trillion; C is degrees Celsius; % is percent.

Table 4-5: Groundwater Nutrient Analysis (ESS 2017).

Note: mg/L is milligrams per liter; L/m²/day is liters per square meter per day.

4.1.2 Lost Lake Water Quality Investigation Report (CEI 2013)

Limited data was collected from the Deep Hole (deepest point) of Lost Lake in July, August, and September 2013 (1 to 2 samples per location). The Deep Hole sampling results are shown in Figure 4-5 (nitrate concentrations) and Figure 4-6 (nitrate + ammonia concentrations). Pore water sampling locations are shown in Figure 4-4. The pore water sampling results are shown in Figure 4-7 (phosphorus), Figure 4-8 (dissolved oxygen), and Figure 4-9 (chlorophyll-a).

The results for both Deep Hole and pore water sampling locations were compared to 1988/1989 water quality data (measured in the 1989 Diagnostic/Feasibility Study [Baystate Environmental Engineers 1989]). The 2013 report indicated that the data comparison results were inconclusive and that there was no trend in the data. Emerging contaminant data were collected as well; however, the report indicated the data results showed very low levels of several emerging contaminants and limited results associated with wastewater.

The report indicated that phosphorus sampling (shown in Figure 4-10 and Figure 4-11) showed the presence of wastewater, high levels of fertilizer, or other sources due to that fact that many of the phosphorus concentrations exceeded 20 parts per billion (ppb; a rough gauge of good water quality) and even 30 ppb (indicative of watershed issues, especially during a wet summer). However, bacteria were also found, which the report indicated showed the presence of untreated sewage from septic systems or livestock.

Figure 4-4: Sampling Locations (CEI 2013).

Figure 4-5: Pore Water Nitrate Concentrations (CEI 2013).

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations (CEI 2013).

Figure 4-7: Deep Hole Phosphorus Levels (CEI 2013).

Note: ppb is parts per billion.

Figure 4-8: Deep Hole Dissolved Oxygen Levels (CEI 2013).

Note: ppm is parts per million.

Figure 4-9: Deep Hole Chlorophyll-a Levels (CEI 2003).

Note: ppm is parts per million.

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation (CEI 2003).

Figure 4-11: Tributary Phosphorus Levels (CEI 2013).

4.1.3 A Diagnostic / Feasibility Study for the Management of Lost Lake / Knopp’s [sic] Pond (Baystate Environmental Engineers 1989)

This report detailed historic water quality conditions in Lost Lake/Knops Pond and identified the major sources of nutrient loadings in 1989, which may or may not reflect current conditions. The report findings are summarized below:

• Sampling Locations. Figure 4-12 shows water quality sampling locations KP-1 (inlet from unnamed tributary), KP-2 (inlet from Martins Pond Brook), and KP-3 through KP-7 (distributed throughout Lost Lake/ Knops Pond).
• Sampling Results. Water quality sampling results are shown in Table 4-6. The study indicated that results suggested Martin’s Pond Brook was a major source of phosphorus loading and that the phosphorus remineralization under anoxic bottom conditions was not an important source to the lake. The study indicated the orthophosphate data results indicate that the pond is mesotrophic. Ammonia levels were highest during the winter and late fall, which according to the study indicated that organic material was decomposing.
• Tributary Sampling Results. Tributary water quality data was shown in Table 4-7. The results indicated that the Gibbet Hill tributary was an important source of nitrogen and phosphorus and may have led to the high nutrient levels in Martin’s Pond Brook. Additionally, the report indicated that the high density of residences near the lake was a potential source of nutrients.
• Well Water Sampling Results. The well water quality data are shown in Table 4-8. The study indicated that bacteria sampling results showed that septic systems were not responsible for the bacteria counts. It also indicated that bacteria counts were most likely due to wildlife, based on the fecal coliform (FC) to fecal streptococci (FS) ratios.
• Nutrient Loading. Additionally, the study calculated nutrients loads based on sampling data and typical export coefficients for sources in Lost Lake/Knops Pond, including the Unnamed Tributary, Martin’s Pond Brook, “Redwater” (shown in Figure 4-12), groundwater (direct input), atmospheric deposition (direct input), bird inputs (direct input), and internal load (anoxic loading). The results of this nutrient load table (shown in Table 4-9) indicated that approximately 63% of the phosphorus load and 51% of the nitrogen load were from the two inlets.
• Overall, the study indicated most of the phosphorus loading (approximately 63%) was from the two inlets, with most from the inlet to Martins Pond Brook. These results concur with the conclusions from the 2013 and 2017 study, which both identify phosphorus as a nutrient of concern within the watershed, although the 2017 study specifically identifies erosion as a major source.

Figure 4-12: Sampling Stations (Baystate Environmental Engineers 1989).

 

 

Table 4-6: Water Quality Data (Baystate Environmental Engineers 1989).

 

Table 4-7: Tributary Water Quality Data (Baystate Environmental Engineers, 1989).

 

Table 4-8: Well Water Quality Data (Baystate Environmental Engineers 1989).

 

 

 

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond (Baystate Environmental Engineers 1989).

 

 

4.1.4 Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

This presentation by GLA on the topic of erosion and stormwater runoff included photos and locations with moderate to severe erosion due to stormwater runoff. Photos from the presentation are shown in Figure 4-13. The following roads and locations were shown:

·         Alder Road	·         Moose Trail
·         Baby Beach	·         Off Prescott Street
·         Birchwood Avenue	·         Paul Revere Trail and Boat Launch
·         Boathouse Road	·         Point Road
·         Highland Road	·         Radio Road
·         Intersection of Pine and Paul Revere Trails	·         Redskin Trail
·         Island Road and Island Road Bridge	·         Shelters Road
·         Juniper Point	·         Summit Avenue
·         Lost Lake Drive at Outlet	·         Wenuchias Trail
·         Maplewood Avenue	·         Weymisset Road

 

Figure 4-13: Photos from GLA Presentation (GLA 2014).

From left to right: Boathouse Road, Paul Revere Trail off Pine Trail (Lost Lake Boat Launch), and Alder Road.

5.0       Water Quality Goals for Lost Lake and Knops Pond (Element B)

Water quality goals are a critical component of watershed management plans; they are the “yardstick” by which management success is measured. The water quality goals describe the pollutant load reductions that indicate improvement in the lake’s water quality. The establishment of water quality goals for Lost Lake/Knops Pond was guided by an analysis of water quality data, nutrient load modeling using the WBP tool, and with input from GPAC and GLA.  

5.1 Estimated Pollutant Loads

GIS was used for the pollutant loading analysis. The land-use data (MassGIS 2009b) was intersected with impervious cover data (MassGIS 2009a) and USDA Natural Resources Conservation Service (NRCS) soils data (USDA NRCS, MassGIS 2012) to create a combined land use/land cover grid. The grid was used to sum the total area of each unique land use/land cover type.

The amount of DCIA was estimated using the Sutherland equations as described above, and any reduction in impervious area due to disconnection (i.e., the area difference between TIA and DCIA) was assigned to the pervious D soil category for that land use to simulate that some infiltration will likely occur after runoff from disconnected impervious surfaces passes over pervious surfaces.

Pollutant loading for key nonpoint source pollutants in the watershed was estimated by multiplying each land use/cover type area by its pollutant load export rate (PLER). The PLERs are an estimate of the annual total pollutant load exported via stormwater from a given unit area of a particular land cover type. The PLER values for TN, TP, and TSS were obtained from USEPA (Voorhees 2016b; see documentation provided in Appendix A) as follows:

L_n = A_n * P_n

Where L_n = Loading of land use/cover type n in pounds per year (lbs./yr.); A_n = area of land use/cover type n (acres); P_n = pollutant load export rate of land use/cover type n in pounds per acre per year (lbs./acre/yr.).

Table 5-1 presents the estimated land-use based TP, TN, and TSS within the Lost Lake/Knops Pond watershed. The largest contributor of land-use based TP, TN, and TSS load originates from areas designated as forested. TP and TN generated from forested areas is generally a result of natural processes such as decomposition of leaf litter and other organic material; the forested portions of the watershed therefore are unlikely to provide opportunities for nutrient load reductions through BMPs. Low density residential areas (including roads) are the second largest contributors of land-use based TP, TN, and TSS load in the watershed. Residential areas provide excellent opportunities for nutrient load reductions through BMPs, as described in the following sections.

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants.

Land Use Type	Pollutant Loading1
	TP (lbs./yr.)	TN (lbs./yr.)	TSS (tons/yr.)

TOTAL	557	3,659	92.13
Forest	299	1,580	61.99
Low Density Residential	87	871	11.96
Agriculture	99	595	8.19
Open Land	27	269	5.18
High Density Residential	23	158	2.34
Commercial	12	109	1.36
Medium Density Residential	9	72	1.04
Industrial	1	6	0.07
Highway	0	0	0.00
1These estimates do not consider loads from point sources or septic systems. Note: TP is total phosphorus; TN is total Nitrogen; TSS is total suspended solids; and lbs./yr. is pounds per year.

 

It is important to note that pollutant loads presented in Table 5-1 do not consider loads from point sources or septic systems. In the Lost Lake/Knops Pond watershed, septic systems have been identified as a potential source of pollutant loading since they are used throughout the watershed. Septic system sources should be separately evaluated to determine whether septic system upgrades or sanitary sewer system conversion would cost-effectively reduce bacteria and nutrient sources in the watershed.

5.2 Water Quality Goals

Many methodologies can be used to set pollutant load reduction goals for a WBP. Goals can be based on water quality criteria, surface water standards, existing monitoring data, existing TMDL criteria, or other data. As discussed in Element A, water quality goals for this WBP are focused on reducing nutrient (TP and TN) and sediment (TSS) loads to Lost Lake/Knops Pond. The water quality goals, and corresponding required loading reductions are included in Table 5-2.

Water quality goals for primary NPS pollutants are listed in Table 5-2 based on the following:

• TMDL water quality goals are used if a TMDL exists for the water body.
• For all water bodies, including impaired waters with a pathogen TMDL, the water quality goal for bacteria is based on theMassachusetts Surface Water Quality Standards (314 CMR 4.00 2013) that apply to the Water Class of the selected water body.
• If the water body does not have a TMDL for TP, a default target TP concentration is provided which is based on guidance provided in the Gold Book. Because there are no similar default water quality goals for TN and TSS, goals for these pollutants are provided in Table 5-2 only if a TMDL exists or alternate goal(s) have been optionally established by the WBP author.
• According to the Gold Book, total phosphorus should not exceed 50 µg/L in any stream at the point where it enters any lake or reservoir. The water quality loading goal was estimated by multiplying this target maximum phosphorus concentration (50 µg/L) by the estimated annual watershed discharge for the selected water body. To estimate the annual watershed discharge, the mean flow was used, which was estimated based on United States Geological Survey (USGS) “Runoff Depth” estimates for Massachusetts (Cohen and Randall 1998). This document provides statewide estimates of annual Precipitation (P), Evapotranspiration (ET), and Runoff depths ® for the northeastern United States. According to their method, R is defined as all water reaching a discharge point (including surface and groundwater) and is calculated by:

P – ET = R

A mean R was determined for the watershed by calculating the average value of R within the watershed boundary. This method includes the following assumptions/limitations:

1. For lakes and ponds, the estimate of annual TP loading is averaged across the entire watershed. However, a given lake or reservoir may have multiple tributary streams, and each stream may drain land with vastly different characteristics. For example, one tributary may drain a highly developed residential area, while a second tributary may drain primarily forested and undeveloped land. In this case, one tributary may exhibit much higher phosphorus concentrations than the average of all streams in the selected watershed.
2. The estimated existing loading value only accounts for phosphorus due to stormwater runoff. Other sources of phosphorus may be relevant, particularly phosphorus from on-site wastewater treatment (septic systems) close to receiving waters. Phosphorus does not typically travel far within an aquifer, but in watersheds that are primarily unsewered, septic systems and other similar groundwater-related sources may contribute a significant load of phosphorus that is not captured in this analysis. As such, it is important to consider the estimated TP loading as “the expected TP loading from stormwater sources.”
3. If the calculated water quality goal is higher than the existing estimated total load, the water quality goal is automatically set equal to the existing estimated total load.

The WBP tool calculates an estimated TP load of 557 lbs./yr. and a water quality goal of 557 lbs./yr. of TP. This would mean that the required load reduction is 0 lbs./yr. to meet the water quality goal. However, the estimated pollutant load and water quality goal do not account for nutrient load from the observed erosion (the soil may be nutrient-rich due to historical agricultural use), septic systems, waterfowl, atmospheric, and/or internal load. The pollutant load also does not account for current land use (e.g., recent development) as the model uses an older land use dataset (2016). Furthermore, observations of roadway erosion and eutrophication throughout the watershed during the site visit indicate that a reduction in nutrient load is required to improve water quality in Lost Lake/Knops Pond.

Therefore, a load reduction of 10% of the existing estimated total load of TP, TN, and TSS is proposed as the required load reduction. Modifications to the required load reduction would be made based on the results of the water quality monitoring program.  

The following adaptive sequence is recommended to sequentially track and meet these load reduction goals:

1. Establish a short-term reduction goal to reduce land-use-based TP, TN, and TSS by 10%. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons per year (tons/yr.) for TP, TN, and TSS, respectively.
2. Implement a baseline water quality monitoring program in accordance with Element I. Results from the monitoring program should advise if Element C BMPs have been effective at addressing listed water quality impairments or water quality goals. Results can further be used to create, periodically inform, or adjust load reduction goals.
3. Establish a long-term reduction goal to reduce land-use-based TP, TN, and TSS over the next 15 years based on monitoring data.

Table 5-2: Pollutant Load Reductions Needed.

Pollutant	Existing Estimated Total Load	Water Quality Target	Required Load Reduction for short-term goal (10%)
Total Phosphorus	557 lbs./yr.	501 lbs./yr.	56 lbs./yr.
Total Nitrogen	3,659 lbs./yr.	3,293 lbs./yr.	366 lbs./yr.
Total Suspended Solids	92 tons/yr.	83 tons/yr.	9 tons/yr.

Note: lbs./yr. is pounds per year.

The proposed BMPs described in this WBP are expected to reduce TP, TN, and TSS loads to Lost Lake/Knops Pond; however, additional BMP implementation/load reduction may be required to meet the water quality goals.

 

6.0       Management Actions to Control Phosphorus (Elements C, D, and E)

The proposed management measures were determined using an iterative process. First, the hotspot map was reviewed, and potential sites located on Town-owned parcels were selected. Next, the field investigation was conducted to assess whether the selected sites are suitable for BMPs and to determine the BMP that best fit site characteristics (e.g., topography, soil type, area). Areas not initially selected were added to the list of potential sites if the area was determined to be suitable for a BMP during the site investigation. After the site investigation, a desktop review was conducted to determine the siting of the BMPs, and the estimated nutrient load reduction based on drainage area and land use. The proposed BMPs were presented to members of the GLA and GPAC during the stakeholder meeting on October 21, 2021. The final proposed BMPs were selected based on feedback from the stakeholder meeting.

Nutrient load reductions for the proposed BMPs were determined using the WBP tool with drainage areas and land use calculated in GIS. The WBP tool also calculates the estimated BMP footprint. The cost estimates for the site-specific BMPs were determined using the initial baseline provided by the WBP tool and adding 30% for design costs, 10% for permitting costs, 10% for project management costs, and 15% for contingency. A 50% contingency was added to represent the maturity level based on the Association for the Advancement of Cost Engineering (AACE) Level 4 cost estimate.

There are two main types of proposed management measures: (1) watershed-wide BMPs that are recommended for implementation throughout the watershed in addition to the key locations specified in this WBP and (2) site-specific BMPs that are recommended for a specific location in the watershed. The proposed management measures are all structural BMPs, except for catch basin cleaning which is a nonstructural or programmatic BMP. Figure 6-1, below, shows the proposed BMP locations.

 

Figure 6-1: Proposed BMP Locations.

6.1 BMP Hotspot Map

BMPs are management measures, activities, and maintenance procedures that prevent or reduce nonpoint source or point source pollution to achieve water quality goals. Examples of BMPs include rain gardens, vegetated swales, and catch basin maintenance. The following points describe the GIS-based analysis conducted within the watershed to identify high priority parcels for BMP implementation:

• Each parcel within the watershed was evaluated based on ten criteria accounting for the parcel ownership, social value, and implementation feasibility (See Table 6-1 for more detail below).
• Each criterion was then given a score from 0 to 5 to represent the priority for BMP implementation based on a metric corresponding to the criterion. (A score of 0 would represent lowest priority for BMP implementation whereas a score of 5 would represent highest priority for BMP implementation.)
• A multiplier was also assigned to each criterion, which reflected the weighted importance of the criterion. (A criterion with a multiplier of 3 had greater weight on the overall prioritization of the parcel than a criterion with a multiplier of 1.)
• The weighted scores for the criteria were then summed for each parcel to calculate a total BMP priority score.

Table 6-1 presents the criteria, indicator type, metrics, scores, and multipliers for this analysis. Parcels with total scores above 60 are recommended for further investigation for BMP implementation suitability.

Figure 6-2 presents the resulting BMP Hotspot Map for the watershed. The following link includes a Microsoft Excel file with information for parcels with a score above 60: hotspot spreadsheet. These parcels are spread out within the watershed and generally are not directly adjacent to Lost Lake/Knops Pond, except for the forested parcels to the northwest of the lake. Additionally, the lack of suitable parcels adjacent to the watershed suggests that proposed BMPs may need to be implemented either in the roadway right-of-way or on smaller parcels of public land, and/or that multiple BMPs may be needed to significantly improve the water quality in the lake. Because several parcels in the northwest portion of the watershed with known current and historic agricultural activities are on the BMP Hotspot map, if monitoring results indicate that agricultural activities are contributing excessive nutrient load to the watershed, BMPs may be implemented in this area.

This analysis solely evaluated individual parcels for BMP implementation suitability and likelihood for the measures to perform effectively within the parcel’s features. This analysis does not quantify the pollutant loading to these parcels from the parcel’s upstream catchment. When further evaluating a parcel’s BMP implementation suitability and cost-effectiveness of BMP implementation, the existing pollutant loading from the parcel’s upstream catchment and potential pollutant load reduction from BMP implementation should be evaluated.

GIS data used for the BMP Hotspot Map analysis included:

• MassGIS (2015a);
• MassGIS (2015b);
• MassGIS (2017a);
• MassGIS (2017b);
• MassGIS (2020);
• Massachusetts Department of Revenue Division of Local Services (2016);
• MassGIS (2005);
• ArcGIS (2020);
• MassGIS (2009b);
• MassGIS (2012); and
• ArcGIS (2020b).

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis.

 

Figure 6-2: BMP Hotspot Map[8]

Ctrl + Click on the map to view a full-sized image in your web browser

6.2 Field Watershed Investigation

Geosyntec conducted a field investigation in the Lost Lake/Knops Pond watershed on August 30, 2021 to identify and confirm sources of pollution and to identify potential BMPs that can be implemented to reduce the pollutant load to Lost Lake/Knops Pond.

Findings from the site visit are described below:

• Birchwood Avenue/Hazelwood Avenue and the “Inlet 2” north of Birchwood Avenue. At this location, erosion was observed along roads and in residential driveways. Here, the stream is small and slow-moving (approximately 3 feet wide with approximately 1-inch-deep flowing water). An observed catch basin on Birchwood Avenue was partially covered with concrete and filled with sediment.
• Off Prescott Road. Here, a dirt road appeared to have been recently regraded.
• Grotonwood Camp At this location, a large parking lot, untreated stormwater runoff appears to concentrate east of the building and discharge into the woods where there was visible erosion. The opportunity exists to implement a stormwater BMP here; this location also has public education and outreach potential. A French drain is also located in this location, which appears to have been more recently installed and collects roof runoff and discharges into the wooded area.
• Martins Pond Brook crossing (culvert) at Martins Pond Road. At this location, catch basin full of sediment was observed.
• Shattuck Street. Here, Martins Pond Road, a dirt road, appears to be contributing sediment to the downstream paved road, where the sediment is entering the catch basins.
• Scarlet Hill Farm (horse farm). Here, the Project Team walked along a portion of the horse farm from Shattuck Street where it abuts Martins Pond Brook; they did not see any evidence of horses having access to the brook.
• Met with John Smigelski at 150 Mill St (Excalibur Farm). John Smigelski showed the Project Team soil sampling data (2011 and earlier years) from his fields off of Groton School Road, which are not within the watershed. The samples indicated elevated levels of TP in the topsoil. John noted that he does not add phosphorus to his soils since the levels are high.
• Lowell Road. Here, it appears that stormwater runoff from Gibbet Hill Grill (restaurant and grazing land) as well as Lawrence Academy discharges to a stormwater pond south of Lowell Road.
• Martin’s Pond Brook crossing (culvert) at Lowell Road. The brook is very slow moving here, and banks are densely vegetated.
• Lost Lake Drive. Here, Martin’s Pond Brook flows through large wetland area. Catch basins along Lost Lake Drive appear to discharge to the wetland.
• Fire Station on Lost Lake Drive. Catch basin with visible sediment buildup on pavement nearby was observed in the driveway; there is the potential for BMP implementation here, though the Project Team suspects that the drainage area is not very large.
• Tavern Road. Erosion was observed on both sides of road; Martins Pond Brook (“Inlet 1”) discharges into the pond east of Tavern Road.
• Boat House Road. Erosion was observed on both sides of road.
• Observed outlet of watershed (beginning of Cow Pond Brook).
• Boat Launch/Fisherman access off of Pine Trail. Erosion and sedimentation were observed in the parking area, as was evidence of sediment loading from Pine Trail down the steep entrance to the parking area. An opportunity to implement a BMP exists at this location. The wetland and pond adjacent to the parking area was stagnant and showed signs of eutrophication
• Highland Road, Radio Road, Weymisset Road, and Island Road. Numerous areas along road and residential driveways with erosion were observed.

Algal blooms, an indication of eutrophication, were present in the ponds that were visited. Locations include off of Radio Road, Tavern Road, the Lost Lake Boat Launch (Pine Trail), and across from Gibbet Hill Grill. These ponds are located throughout the watershed and demonstrate evidence of excessive nutrients.

Erosion on the sides and slopes of paved roads was present throughout the watershed. Loss of vegetation was also noted. The erosion was especially pronounced and of concern on the “esker” roads, located directly adjacent to Lost Lake/Knops Pond. In many cases, this erosion also presented road stability concerns, as road foundations were eroding into the lake. Figure 6-3, below, shows examples of erosion in the watershed.

Figure 6-3: Erosion off Paved Roads.

From left to right, erosion on Island Road, Radio Road, and Pine Trail.

Gullying and channelization were observed on Radio Road and Pine Trail. On the slope of Radio Road, evidence of stormwater runoff flowing directly into Lost Lake/Knops Pond was observed. Loss of vegetation was observed on Island Road and Pine Tail.

Erosion was present on unpaved roads throughout the watershed. Additionally, evidence of regrading (parked equipment and fresh soil) of dirt roads was found on Off Prescott Street. Figure 6-4 shows examples of erosion on unpaved roads.

Figure 6-4: Erosion on Unpaved Roads.

From left to right, erosion on Off Prescott Street, Birchwood Ave, and Shattuck Street.

Gullying and channelization were observed on Birchwood Avenue and Shattuck Street.

Maintenance needs were also observed at several locations during the field investigation. Sediment was found in catch basins at the intersection of Chester Hill and Martins Pond Road, and there are likely other catch basins in the watershed that require cleaning. Additionally, a catch basin on Maplewood Avenue was partially covered by concrete tiles and filled with sediment.

In addition to the field investigation, the Project Team also contacted large land users in the watershed about their land management practices. The findings from the conversations are summarized below:

• Scarlet Hill Farm. This horse farm has a public trail easement. No significant erosion or other sources of nutrients were observed during the site visit. A stream runs adjacent to the public trail.
• Gibbet Hill/Weber Restaurant Group. There are two main land uses on this property: a leased-out 100% organic vegetable farm and a Black Angus cattle farm with 100 acres for grazing, a 2.5-acre field, ½-acre for lamb pasture and ¼-acre for pigs. There is no irrigation.
• Grotonwood Camp. No fertilizer is used at this property. There is an infiltration system for roof drains and no other constructure stormwater management. This land user expressed interest in future partnering on projects.
• Groton Country Club. A phosphorus free fertilizer is applied to the putting greens once a year and to the fairways in the spring. The fertilizer is not applied on open areas or roughs.
• Lawrence Academy. No information was provided. No significant sources of erosion or other sources of nutrients were identified from the road adjacent to the site.
• Excalibur Farm. Although Excalibur Farm is located outside of the watershed, geological and soil attributes at the farm may be like those within the watershed. Soil tests indicate high phosphorus concentrations, although the source may be from the historical agricultural use, soil properties, or other sources.
• Department of Public Works for Town of Groton. Both salt and sand are used on roads within the watershed and on roads directly adjacent to the watershed. The application varies based on the type of storm: for icy storm, sand is used and for storms with less ice, only salt is used. Calcium chloride is often used with the salt. Typically, the roads adjacent to Lost Lake/Knops Pond are salted/sanded once per storm. The applicator machines are calibrated to use the minimum amount of salt and sand needed to provide deicing.

6.3 Existing Management Measures

Existing management measures in Lost Lake/Knops Pond mostly consist of in-lake treatments to control invasive plants. The following timeline show the progression of herbicide treatments:

• 2002: Herbicidal treatment of the entire lake for the control of milfoil was successful in reducing weed growth (GLA 2012).
  • 2003–2004: Spot treatments were conducted to control regrowth (GLA 2012).
• 2003–2011: Limited work was conducted. A weed harvester operated by GLA was used to control new growth (GLA 2012).
• 2011: GLA hired Aquatic Control Technology to conduct a biological survey and propose management alternatives (GLA 2012).
• 2011–2012: GLA continued use of the weed harvester; weed regrowth, specifically of milfoil and Cabomba was intense due to warmer than typical weather (GLA 2012).
• 2017: Herbicide treatment was applied by Solitude Lake Management and focused on areas of dense milfoil, curlyleaf pondweed, and fanwort growth that were identified during a pretreatment survey. Reward (diquot) and Clipper (flumioxazin) were applied to 74 acres (Solitude 2017).
  • Water quality samples were collected, and blue/green cell counts were found to be 540 cells per milliliter (cells/mL), below the Massachusetts Department of Public Health contact threshold of 70,000 cells/mL (Solitude 2017).

Overall, there has been limited success in controlling the invasive plant population in the lake. It should be noted that the algal blooms prevent aquatic plants from growing. If the algal blooms are reduced and the water clarify improves, it is expected that the aquatic plant growth will increase substantially.  

6.4 Watershed-Wide BMPs

The major source of pollution, as determined in past studies and through observations during site investigation, is erosion from unpaved roads and from the slopes of paved roads. Erosion was observed throughout the watershed but is of particular concern around the lake on the “esker” roads. This erosion is both a water quality and safety issue, as the sediment is flowing directly into the lake, carrying nutrients with no attenuation from overland flow, and is eroding from under the road, causing concern regarding the structural integrity of the roads. As such, the watershed-wide BMPs that address erosion (e.g., slope stabilization and dirt road BMPs) should be prioritized. Erosion is also causing many catch basins throughout the watershed to be filled with sediment.

The following watershed-wide BMPs are proposed:

• Slope Stabilization off of Paved Roads. As discussed in the site visit summary, there is severe erosion at many of the paved roads throughout the watershed, especially at the “esker” roads directly adjacent to Lost Lake/Knops Pond. Roads in need of slope stabilization observed during the site visit include Island Road, Radio Road, Weymisset Road, Moose Trail, and Boat House Road, although there may be additional locations for slope stabilization within the watershed. There are several potential methods of slope stabilization, including reseeding with native plants and installing fabric filters (such as jute or geotextiles). While reseeding, it is important to be mindful of limiting fertilizer use, to avoid additional nutrient loading. There are three main components to the slope stabilization: topsoil, hydroseeding (including fertilizer), and an optional erosion control blanket. A cost estimate is shown in Table 6-2.

Table 6-2: Slope Stabilization Cost Estimates

Approximate Site Area (square feet)

Topsoil & Seeding

Topsoil, Seeding, & Erosion Control Blanket

	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)
500	$1,200 ($840 to $1,800)	$2.40  ($1.68 to $3.60)	$2,200  ($1,540 to $3,300)	$4.50 ($3.15 to $6.75)
2,000	$4,800  ($3,360 to $7,200)	$2.40 ($1.68 to $3.60)	$9,000  ($6,300 to $13,500)	$4.50 ($3.15 to $6.75)
10,000	$23,800  ($16,660 to $35,700)	$2.40  ($1.68 to $3.60)	$44,900  ($31,430 to $67,350)	$4.50 ($3.15 to $6.75)
50,000	$119,000 ($83,300 to $178,500)	$2.40  ($1.68 to $3.60)	$224,500 ($157,150 to $336,750)	$4.50  ($3.15 to $6.75)

• Dirt Road BMPs. Many of the dirt roads throughout the watershed showed signs of moderate to severe erosion, including Maplewood Avenue, Birchwood Avenue, Off Prescott Street, and Shattuck Street. The Massachusetts Unpaved Roads BMP Manual (MassDEP 2011) includes a variety of potential dirt road BMPs. Proposed solutions to dirt road erosion include maintaining natural buffers and drainage ways, general shoulder maintenance, and structural measures such as regrading roads, installing waterbars, and lining ditches. Figure 6-5 shows an example of two types of ditches.

 

Figure 6-5: Typical Ditch Detail (MassDEP 2011)

We recommend that GLA and GPAC coordinate with the Town of Groton on any dirt road-related projects or grant proposals.

• Catch Basin Maintenance and Structural BMPs. As described in the site visit summary, many catch basins throughout the watershed were filled with sediment due to erosion, including catch basins located on Maplewood Avenue, Shattuck Street, and Prescott Street. The catch basins should be cleaned in coordination with the Town of Groton. Stabilizing the dirt roads and slopes can help reduce erosion; however, in addition, small collection sumps and/or rain gardens can be installed upstream of drain inlets. The catch basin on Maplewood Avenue was filled with sediment and partially covered with concrete tiles. This catch basin should either be fully covered to prevent sediment from entering the sump and subsequently the drainpipes that discharge to Lost Lake/Knops Pond or opened to receive stormwater runoff. Modifications can also be made to the catch basin inlet and sump to better capture sediment to prevent discharge into the lake or its tributaries. Figure 6-6 shows an example of a catch basin filtration inlet system that removes sediment and oil from stormwater runoff (New Pig 2021).

 

Figure 6-6: Catch Basin Filtration Inlet System (New Pig 2021)

6.5 Site-Specific BMPs

We also identified several site-specific proposed management measures as opportunities to capture and slow runoff and reduce pollutant loading. The six site-specific BMPs are the Grotonwood Camp raingarden, the Boat Launch raingarden, the Boat Launch swale, the Birchwood Road swale, the Shattuck Street lot raingarden, and the Shattuck Street swale. The conceptual design sheets for the proposed BMPs are included as Appendix B. The site-specific BMPs should be implemented in conjunction with the site-specific BMPs, as it is unlikely that the site-specific BMPs alone will provide enough nutrient load removal to resolve the water quality issues within the watershed. The site-specific BMPs are described in more detail below:

• Grotonwood Camp Raingarden. The proposed raingarden will infiltrate stormwater runoff from the Grotonwood Camp main parking lot, a relatively large area of impervious surface for the watershed. Currently, there are signs of erosion at the edge of the forest where the stormwater runoff channelizes from the parking lot. The proposed raingarden would mitigate this erosion and provide stormwater quantity and quality benefits, such as reducing peak flows from the parking lot and reducing the nutrient and sediment load. Although the stormwater runoff does not discharge directly to a tributary or Lost Lake/Knops Pond, it discharges approximately 100 feet from a stream that runs through Grotonwood Camp.
• Boat Launch Raingarden. The proposed boat launch raingarden at the Lost Lake Public Boat Launch will infiltrate stormwater runoff from the boat launch parking lot, which is mostly paved. The Boat Launch Swale, described below, will treat stormwater runoff from the paved road (off Pine Trail) that leads down to the parking lot. Currently, there is significant erosion at the boat launch. Additionally, there is eutrophication in the pond directly adjacent to the boat launch, indicating excessive nutrient loads. Installing a raingarden at the boat launch would infiltrate stormwater runoff, reducing erosion, and mitigate the nutrient load that enters the lake directly.
• Boat Launch Swale. The proposed boat launch swale will work in conjunction with the raingarden described above. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loads from the road leading to the boat launch. The road is paved and moderately steep and there are signs of erosion on either side of it. As the stormwater runoff is already directed towards the sides of the road, installing a swale will provide water quality treatment instead of carrying nutrients and sediment towards the boat launch and subsequently to Lost Lake/Knops Pond, as is currently occurring due to channelized flow.
• Birchwood Avenue Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loading from Birchwood Road. Birchwood Avenue is a paved, steep, winding road with observed erosion at the outer edge where the road curves. The erosion is severe, with defined channels and gullies on the slope of the road. Stormwater runoff from Birchwood Avenue flows into the Unnamed Tributary that leads directly into Lost Lake/ Knops Pond.
• Shattuck Street Lot Raingarden. The proposed Shattuck Street Lot raingarden will infiltrate stormwater runoff from Shattuck Street and part of Scarlet Hill Farm. The proposed location is the parking lot for the public access trails at Scarlet Hill Farm that run adjacent to a stream that is a tributary for Lost Lake/Knops Pond. Although Scarlet Hill Farm has received awards for their manure practices, agricultural land tends to have higher pollutant loads than forested or open land.
• Shattuck Street Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff from Shattuck Street and the surrounding area and mitigate the nutrient loads. Like the Shattuck Street Lot raingarden, the drainage area for the swale also includes agricultural land at Scarlet Hill Farm. In addition, there is severe erosion on Shattuck Street, which is unpaved (gravel) with a moderately steep slope; therefore, installing the swale would reduce the erosion by reducing stormwater runoff and mitigate the associated nutrient load.

More information about the construction and operation and maintenance (O&M) of each type is included below.

Raingardens/Bioretention Areas (MassDEP 2016a):

• Raingardens use soil, plants, and microbes to treat stormwater before it infiltrates into the soil or is discharged. They can provide pollutant removal and infiltrate up to 1 inch of rainfall, in addition to providing groundwater recharge.
• Raingardens are comprised of shallow depressions with a layer of sandy soil, mulch, and planted with dense vegetation. Generally, they are designed to pond to a depth of water 6 to 8 inches deep. The soil mix should be sandy loam or loamy sand with a clay content of less than 15%.
• Soil and any eroded areas should be inspected monthly, and litter and debris should be removed accordingly. Invasive species should be removed as needed and mulch replaced every two years. With proper selection of plants, the need for fertilizers and pesticides should be eliminated or at least very minimal. This is especially important for the Lost Lake/Knops Pond watershed, as introducing additional nutrient loads would be detrimental to water quality and negate the use of the raingarden.

Treatment Swales (MassDEP 2016a):

• Water quality or treatment swales are vegetated open channels that convey runoff and treat the stormwater runoff.
• Soil characteristics, flow capacity, erosion resistance, and vegetation should be considered when designing a treatment swale.
• Swale maintenance includes inspecting swales to ensure vegetation health and lack of erosion (once per month initially, then twice per year); mow if necessary (as needed); remove sediment and debris manually (at least once per year), and re-seed as necessary).

6.6 Non-Structural BMPs and Watershed Outreach (Category 5)

Non-structural BMPs typically do not involve construction and are often more broadly applied throughout a watershed. Implementation of these BMPs can result in significant load reductions. Examples of non-structural BMPs include:

• Municipal “good housekeeping” practices such as street sweeping and leaf litter collection programs can reduce phosphorus loading by reducing transport of pollutants through stormwater systems.
• Regulations can be used to help affect behavior change and manage land uses practices; examples of regulatory tools include stormwater management regulations, septic system ordinances, fertilizer regulations, pet waste removal requirements, and more.
• Outreach and education can also be used to help change behavior and reduce pollutant loading by encouraging and promoting activities that reduce or prevent pollutant loading such as fertilizer reduction incentives, pet waste pick-up programs, pond-friendly landscaping workshops and more.
• Land conservation is a common tool that can be used to prevent loading from land conversion activities.

Table 6-3 summarizes potential non-structural BMPs that can be implemented throughout the watershed.

Table 6-3: Non-Structural BMPs

Non-Structural BMP	Description	Responsible Party
Fertilizer Program	Reduce the amount and frequency of fertilizer application[9] to pervious developed areas throughout the watershed.	Town of Groton; GPAC; GLA
Street Sweeping	Optimize street sweeping locations and frequency equivalent to two times a year sweeping (in Spring and Fall) of 50% of roads within 650-feet of the shoreline, using vacuum assisted sweeper.	Town of Groton
Leaf Litter Management	Provide leaf collection at least 4 times during October and November for properties within 650-feet of the shoreline. Within 24 hours of leaf collection, collect remaining leaf litter on paved streets using a cleaning machine, such as a mechanical broom or vacuum assisted street cleaner.	Town of Groton
Shoreline Buffer	Retrofit developed areas along shoreline with 20-ft-no-mow/no-alteration grassed buffer for properties within 425-feet of the shoreline.	Town of Groton
Regulations	Establish municipal regulations to enable and promote improved stormwater management, buffer protections, and shoreland controls.	Town Planning Staff
Land Conservation	Coordinate with groups to prioritize land conservation goals/target parcels to reduce future load associated with new development.	Town Planning Staff; GPAC; GLA
Impervious Disconnection	Direct runoff from impervious areas such as roadways, parking lots, and roofs, and discharge it to adjacent vegetated permeable surfaces that are of sufficient size with adequate soils to receive the runoff without causing negative impacts to adjacent down-gradient properties.	Town of Groton

Watershed outreach will take place through educational kiosks at the proposed raingardens. These kiosks will include information on water quality in Lost Lake/Knops Pond, the purpose of the stormwater BMPs and their impact on water quality, and actions residents can take to improve water quality in the watershed.

The target audiences include residents in the watershed, recreational users of Lost Lake/Knops Pond (boaters, beach-goers, etc.), and watershed organizations and other user groups (GLA, GPAC, etc.)

GLA and/or GPAC may coordinate with the Town of Groton on distribution of educational materials such as lawn and landscaping education, pet waste management, car washing, and other topics. GLA and/or GPAC may also use their mailing lists to distribute residential educational materials, such as resident pet waste information, septic system handouts, and handouts on residential yard care, found on Think Blue Massachusetts’s website (Think Blue Massachusetts | Residents).

7.0       Schedule and Milestones (Elements F and G)

The project schedule and milestones presented in this section will enable project partners to track management activities over time as the Last Lakes and Knops Pond Watershed-Based Plan is implemented.

Table 7-1 provides a preliminary schedule for implementation of recommendations provided by this WBP. It is expected that the WBP will be reevaluated and updated in 2024, or as needed, based on ongoing monitoring results and other efforts. New projects will be identified through future data analysis, and stakeholder engagement and will be included in updates to the implementation schedule.

 

 

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Structural & Nonstructural BMPs
Slope Stabilization 1 to 2 sites per year	Apply for 604b grant funding to prioritize sites and create conceptual designs.	Apply for Section 319 funding to implement BMPs.	Implement BMPs; Conduct annual maintenance on constructed BMPs; Apply for Section 319 funding for additional sites.
	12/1/2022	12/1/2023	12/1/2024
Dirt Road BMPs 1 road segment per year	Apply for Section 319 or 604b grant funding.	Improve 1 road segment per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Catch Basin Cleaning	Schedule meeting with Town of Groton to discuss catch basin cleaning schedule.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Maintenance	Schedule meeting with Town of Groton to discuss catch basin maintenance.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Inlet/Sump Modification	Apply for Section 319 or 604b grant funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Site-specific BMPs 1-2 per year based on prioritization matrix	Apply for Section 319 funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024

 

Public Education & Outreach
Install Educational Kiosk	Install educational kiosk with BMP construction.
	12/1/2023

 

Monitoring
Monitoring Plan	Conduct four sampling events per year[10].
	Annually

 

8.0       Success Indicators and Evaluation (Element H)

The water quality target concentration(s) is presented under Element A of this plan. To achieve this target concentration, the annual loading must be reduced to the amount described in Element B. Element C of this plan describes the various management measures that will be implemented to achieve this targeted load reduction. The evaluation criteria and monitoring program described below will be used to measure the effectiveness of the proposed management measures (described in Element C) in improving the water quality of Lost Lake/Knops Pond:

• Indirect Indicators of Load Reduction. Indicators of excessive nutrient load include moderate to severe erosion and eutrophication in ponds or in Lost Lake/Knops Pond itself. Therefore, the absence of erosion, especially close to Lost Lake/Knops Pond or its tributaries, and/or the absence of eutrophication will indicate successful load reduction. In addition, nuisance algae and vegetation monitoring in Lost Lake/Knops Pond can also indicate water quality trends.
• Direct Indicators (Measurements) of Load Reduction. Results of the water quality monitoring will also indicate progress towards nutrient load reduction, specifically a reduction in phosphorus in both the Unnamed Tributary and in Martins Pond Brook. See Element I for more information about the water quality monitoring plan.
• Project-Specific Indicators. As previously discussed, the absence of erosion and eutrophication will likely indicate success in reducing the nutrient load. Specifically, areas near constructed watershed-wide or structural BMPs will indicate that these projects are successful.
  • Number of BMPs Installed. Element C of this WBP recommendations the installation of structural BMPs at six locations and recommends several watershed-wide BMPs. The anticipated pollutant load reduction has been documented for each proposed BMP, and the number of BMPs installed will be tracked and quantified as part of this program. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning and slope stabilization).
• TMDL Criteria. Lost Lake/Knops Pond is not currently subject to a non-native aquatic plant TMDL; therefore, this criterion is not applicable. However, please note that Lost Lake/Knops Pond does have a Mercury in Fish Tissue TMDL.

9.0 Monitoring Plan (Element I)

This WBP recommends implementation of a volunteer water quality monitoring program. The purpose of the monitoring program is to refine the location of and quantify sources of pollution. Through previous studies and the site visit, sources of pollution are reasonably well known; however, monitoring would allow for source contributions to be evaluated and quantified spatially. Because this program will help identify priority sources, it will lead to more effective implementation of BMPs. Additionally, monitoring will allow for a quantitative measure of BMP effectiveness by comparing concentrations of TP, TN, and TSS before and after the implementation of BMPs.  Elements of the recommended monitoring plan are summarized below:

• The monitoring plan locations were chosen based on accessibility and proximity to suspected sources of pollution and nutrients. In terms of accessibility, sampling locations were chosen to be close to a road or street and not along steep slopes. An exception is the Martins Pond Brook inlet which may need to be accessed via private property or by boat. The sampling locations chosen are downstream of suspected sources of pollution and nutrients to target areas identified as contributing pollution and nutrients to the watershed, based on previous reports and the site visit. Figure 9-1 shows the proposed monitoring locations. The monitoring locations are described below.
  • Outlet of Martins Pond Brook. This area, currently conservation land, features historical agricultural use. Previous reports have identified Martins Pond Brook as a source of phosphorus (ESS 2017).
  • Martin’s Pond at Lowell Street. This upstream area has historical and current agricultural use (Scarlet Hill Farm). Additionally, the Lowell Street culvert is fairly accessible for sampling.
  • Martins Pond Brook Inlet. The sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations.
  • Unnamed Tributary Inlet. This sampling location was chosen to determine if residential and developed areas are contributing to the phosphorus load.
  • Unnamed Tributary at Boston Road. Like the Martins Pond Brook inlet, this sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations. The road crossing at this location provides accessibility.
• In-Lake Sampling. In-lake sampling is recommended to ensure that the in-lake phosphorus concentration remains below the target concentration of 50 ug/L. Samples could be taken at locations in Lost Lake/Knops Pond, specifically at the deepest locations (at multiple points in the water column) and at areas next to slopes noted for erosion due to stormwater runoff.
• At a minimum, sampling parameters should include TP, dissolved phosphorus, and total suspended solids.
• When to Sample. Sampling should be conducted during both dry and wet weather events to best capture the behavior of sources of pollution. A minimum of two dry and two wet weather events should be conducted annually in the fall, spring, and summer to assess temporal and seasonal trends.
• Quality Assurance/Quality Control (QA/QC). As the results from the volunteer monitoring program will be used for internal guidance only, developing a quality assurance project plan (QAPP) is not required. However, it should be noted that a QAPP is required to submit data to MassDEP and is recommended to help ensure data quality.
• Interpretation of Results/Data Analysis. The results of each sampling location should be compared both to the results of other sampling locations and to results from prior sampling events to determine seasonal trends, temporal trends, and/or the efficacy of any implemented solutions. By comparing the results at sampling locations upstream and downstream of each tributary, sources of pollution may be able to be determined. For example, comparing phosphorus results upstream and downstream of the forested area adjacent to the Martin’s Brook Pond tributary may help to determine if natural sources of phosphorus (i.e., leaf litter) are a large contributor to the overall phosphorus levels.
• Refinement of Monitoring Plan. Potential future changes to the monitoring plan include refining locations to pinpoint specific source areas; collecting runoff sampling from bare soil or agricultural areas if access is provided by the landowners; finger printing of inlet concentrations compared to solid soil data to further refine sources of pollution; additional in-lake or watershed septic source evaluations (e.g., DNA markets, advanced chemical indicators, nutrient isotopes); and additional in-lake monitoring at various depths throughout Lost Lake/Knops Pond.

 

 

Figure 9-1: Proposed Monitoring Locations.

10.0 Funding for Future Watershed Planning Phases and Implementation

10.1 Cost Estimate and Pollutant Load Reduction Estimates

Table 10-1 presents the estimated pollutant load reductions and costs for the proposed management measures.

 

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs[11].

Site-Specific BMP	Drainage Area (ac)	BMP Footprint (sf)/BMP Length (ft)	BMP Design Storm Depth (in)	Estimated Pollutant Removal			Estimated Annual O&M Costs[12]	Estimated Cost
				Total Phosphorus (lbs./year)	Total Nitrogen (lbs./year)	Total Suspended Solids (lbs./year)
Grotonwood Camp Raingarden	0.47	440 sf	0.5	0.5	4.0	191.2	$2,000	$21,200
Boat Launch Raingarden	0.47	405 sf	0.5	0.5	3.6	171.6	$2,000	$21,700
Boat Launch Swale	0.36	50 ft	0.5	0.1	0.1	42.2	$1,000	$12,800
Birchwood Avenue Swale	0.16	40 ft	0.5	0.1	0.2	45.5	$1,000	$5,700
Shattuck Street Lot Raingarden	1.23	445 sf	0.5	0.5	3.2	134.4	$2,000	$56,700
Shattuck Street Swale	0.36	60 ft	0.5	0.1	0.3	84.3	$1,000	$48,800

Note: ac is acres; sf is square feet; lbs./year is pounds per year; O&M is operation and maintenance.

Table 10-2 presents a priority matrix to guide future work and grant funding based on the following criteria:

• Cost/TP Removed. The estimated cost to construct the structural BMP divided by the pounds of total phosphorus removed per year to get a cost per pound of phosphorus removed.
• Cost/TN Removed. The estimated cost to construct the structural BMP divided by the pounds of total nitrogen removed per year to get a cost per pound of nitrogen removed.
• An evaluation of whether adequate space and topographical/geological conditions are available to construct the BMP (e.g., considering slope, soil type).
• Structural BMPs, especially raingardens with educational kiosks, can be used to educate the public about stormwater and water quality. Therefore, the visibility of each proposed structural BMP was considered (e.g., if it is in an often-used space, proximity to road).
• Public/Private. Constructing structural BMPs on public property tends to be more ideal than working with the landowner to install a BMP on private property.
• Proximity to Lake/Tributary. Structural BMPs installed close to the lake or a tributary will prevent nutrients and sediment from directly entering the lake without any attenuation. Therefore, these BMPs are prioritized.

The ranking is on a scale of one to five with five being the most optimal.

Table 10-2: Proposed Structural BMP Priority Matrix.

Structural BMP	Cost/TP Removed	Cost/TN Removed	Feasibility	Visibility	Public/ Private	Proximity to Lake/ Tributary	Sum	Rank
Slope Stabilization	4	4	4	3	5	5	25	High
Dirt Road BMPs	4	4	4	3	5	3	23	High
Catch Basin BMPs	5	5	5	1	5	3	24	High
Grotonwood Camp Raingarden	3	3	4	3	1	1	15	Low
Boat Launch Raingarden	3	1	3	4	5	5	21	High
Boat Launch Swale	5	5	4	3	5	4	26	High
Birchwood Avenue Swale	5	5	3	2	5	3	23	High
Shattuck Street Lot Raingarden	3	3	4	3	1	4	18	Medium
Shattuck Street Swale	4	4	4	2	5	3	22	High

Note: TP is total phosphorus and TN is total nitrogen.

10.2 Funding for Proposed Management Measures

The funding needed to implement the proposed site-specific BMPs (described in Element C) is presented in Table 10-3. The total cost for the program was estimated at $237,000 with estimated annual O&M costs of $14,500 or more. Table 10-3 presents the funding needed to implement the management measures presented in this watershed plan. The table includes costs for BMPs and operation and maintenance activities.

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan.

Management Measures	Location	Capital Costs[13]	Annual O&M Costs	Relevant Authorities	Technical Assistance Needed	Funding Needed[14]
Watershed-wide BMPs (from Element C)
Slope Stabilization - Reseeding	Watershed-wide	$23,800 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$23,800
Slope Stabilization – Reseeding & Fabric Filter	Watershed-wide	$44,900 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$44,900
Dirt Road BMPs	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Cleaning	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Maintenance	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Inlet/Sump Modification	Watershed-wide	$295 each plus labor costs	$1,475 for 5 replacement inserts plus labor	Town of Groton; GLA; GPAC	Permitting and Construction	$1,475 for 5 inserts plus permitting and labor costs
Site-specific BMPs (from Element C)
Bioretention and Rain Garden	Grotonwood Camp Raingarden	$21,216	$2,000	Town of Groton; Grotonwood Camp	Engineering Design and Construction	$21,216
Bioretention and Rain Garden	Boat Launch Raingarden	$21,676	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$21,676
Grassed Channel/Water Quality Swale	Boat Launch Swale	$12,811	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$12,811
Grassed Channel/Water Quality Swale	Birchwood Rd Swale	$5,693	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$5,693
Bioretention and Rain Garden	Shattuck Street Lot Raingarden	$56,727	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$56,727
Grassed Channel/Water Quality Swale	Shattuck Street Swale	$48,753	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$48,753
Information/Education (see Element E)
Monitoring and Evaluation (see Element H/I)
Total Funding Needed:						$237,000
Funding Sources:
MassDEP Section 319 and 604b Grants

11.0 Conclusions

As stated in Section 1.2 of this WBP, the long-term goal is to reduce total phosphorus and other nutrient and sediment loadings to Lost Lake/Knops Pond. The water quality goals (described in Section 5.2) will be accomplished through installation of BMPs throughout the watershed (described in Section 6.0) and will be measured through water quality monitoring efforts (described in Section 9.0). The action items for this WBP are described below.

• BMP Implementation. Implement BMPs throughout the watershed to achieve a 10% reduction in nutrient load as an interim goal. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons/yr. for TP, TN, and TSS, respectively.
• Grant Funding. Apply for MassDEP Section 319 and 604b grants[15] for implementation of BMPs and additional planning, such as determining sites for slope stabilization.
  • Section 319 Nonpoint Source Grant. This program is used for implementation projects that address the prevention, control, and abatement of nonpoint source pollution. Generally, eligible projects must implement measures that target the major source(s) of nonpoint source pollution within a watershed, contain an appropriate method for evaluating the project results, and must address activities identified in the Massachusetts NPS Management Plan.
  • Section 604b Nonpoint Source Grant. This program is used for eligible entities to conduct watershed based nonpoint source assessment and planning projects that result in the following: development of preliminary designs and implementation plans that will address water quality impairments in impaired watersheds, determination of the nature, extent, and causes of water quality problems, and determination of pollutant loads necessary to meet water quality standards.
• Indicators of Success. The monitoring program and other indicators will be used to measure the effectiveness of the implemented BMPs.
  • Monitoring Program (Direct Measurements). Results of the water quality monitoring will indicate progress towards nutrient load reduction.
  • Indirect Indicators. Indirect indicators include the absence of eutrophication in ponds in the watershed and in Lost Lake/Knops Pond and the absence of erosion throughout the watershed. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning).
  • Project Specific Indicators. The number of BMPs installed will be tracked and quantified as part of this WBP.
• Long-Term Goals. The long-term goals will be adapted based on the results of the water quality monitoring and the indicators of success.

 

•  

12.0 References

314 CMR 4.00. 2013. Division of Water Pollution Control, Massachusetts Surface Water Quality Standards. https://www.arcgis.com/home/item.html?id=be2124509b064754875b8f0d6176cc4c.

ArcGIS. 2020a. USA Soils Hydrologic Group. Imagery Layer.

ArcGIS. 2020b. “USA Soils Water Table Depth.” Imagery Layer.

Cohen, A. J. and A. D. Randall. 1998. Mean annual runoff, precipitation, and evapotranspiration in the glaciated northeastern United States, 1951-80. Prepared for United States Geological Survey, Reston VA.

Geosyntec. 2014. Least Cost Mix of BMPs Analysis, Evaluation of Stormwater Standards Contract No. EP-C-08-002, Task Order 2010-12. Prepared for Jesse W. Pritts, Task Order Manager, U.S. Environmental Protection Agency.

Geosyntec. 2015. Appendix B: Pollutant Load Modeling Report, Water Integration for the Squamscott-Exeter (WISE) River Watershed.

 GLA. 2012. Lost Lake/Knops Pond Resource Management Plan. Prepared by Groton Lakes Association. Revision 4.01. August 12, 2012.

King, D. and P. Hagan. 2011. Costs of Stormwater Management Practices in Maryland Counties. University of Maryland Center for Environmental Science Chesapeake Biological Laboratory. October 11, 2011.

Leisenring, M., J. Clary, and P. Hobson. 2014. International Stormwater Best Management Practices (BMP) Database Pollutant Category Statistical Summary Report: Solids, Bacteria, Nutrients and Metals. Geosyntec Consultants, Inc. and Wright Water Engineers, Inc. December 2014.

Massachusetts Department of Revenue Division of Local Services. 2016. Property Type Classification Codes, Non-arm’s Length Codes and Sales Report Spreadsheet Specifications. June 2016.  https://www.mass.gov/files/documents/2016/08/wr/classificationcodebook.pdf

MassDEP. 2001. The Massachusetts Unpaved Roads BMP Manual. Prepared by Berkshire Regional Planning Commission and prepared for Massachusetts Department of Environmental Protection and U.S. Environmental Protection Agency. Winter 2001.

MassDEP. 2012. Massachusetts Year 2012 Integrated List of Waters Final Listing of Massachusetts' Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act.

MassDEP. 2016a. Massachusetts Clean Water Toolkit.

MassDEP. 2016b. Massachusetts Stormwater Handbook, Vol. 2, Ch. 2, Stormwater Best Management Practices.

MassDEP. 2019. Massachusetts Year 2016 Integrated List of Waters Final Listing of Massachusetts’ Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act. December 2019.

MassGIS. 1999. Networked Hydro Centerlines. Shapefile.

MassGIS. 2001. USGS Topographic Quadrangle Images. Image.

MassGIS. 2005. Elevation (Topographic) Data (2005). Digital Elevation Model.

MassGIS. 2007. Drainage Sub-basins. Shapefile.

MassGIS. 2009a. Impervious Surface. Image.

MassGIS. 2009b. Land Use (2005). Shapefile.

MassGIS. 2012. 2010 U.S. Census Environmental Justice Populations. Shapefile.

MassGIS. 2013. MassDEP 2012 Integrated List of Waters (305(b)/303(d)). Shapefile.

MassGIS. 2015a. Fire Stations. Shapefile.

MassGIS. 2015b. Police Stations. Shapefile.

MassGIS. 2017a. Town and City Halls. Layer.

MassGIS. 2017b. Libraries. Layer.

MassGIS. 2020. Massachusetts Schools (Pre-K through High School). Data layer.

MassGIS. 2021. Standardized Assessors’ Parcels. Mapping Data Set.

New Pig. 2021. “PIG® Oil & Sediment Catch Basin Filtration System – Large.” < Storm Drain Filter Insert for Oil & Sediment – New Pig>. Accessed November 19, 2021.

Solitude Lake Management. 2017. Annual Report 2017 Aquatic Vegetation Management Program Lost Lake & Knops Pond. Prepared for Groton Lakes Associated & Town of Groton. December 2017.

Schueler, T.R., L. Fraley-McNeal, and K. Cappiella. 2009. “Is impervious cover still important? Review of recent research.” Journal of Hydrologic Engineering 14 (4): 309-315.

United States Bureau of Labor Statistics. 2016. Consumer Price Index.

United States Geological Survey. 2016. National Hydrography Dataset, High Resolution Shapefile.

University of Massachusetts, Amherst. 2004. Stormwater Technologies Clearinghouse.

USDA NRCS and MassGIS. 2012. NRCS SSURGO-Certified Soils. Shapefile.

USEPA. 1986. “Quality Criteria for Water (Gold Book).” EPA 440/5-86-001. Office of Water, Regulations and Standards. Washington, D.C.

USEPA. 2010. EPA's Methodology to Calculate Baseline Estimates of Impervious Area (IA) and Directly Connected Impervious Area (DCIA) for Massachusetts Communities.

Voorhees, Mark, USEPA. 2015. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

Voorhees, Mark, USEPA. 2016a. “FW: EPA Region 1 SW BMP performance equations.” Message to Chad Yaindl, Geosyntec Consultants. January 25, 2016. E-mail.

Voorhees, Mark, USEPA. 2016b. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

 

Water Quality Assessment Reports

“Merrimack River Watershed 2004 Water Quality Assessment Report”

 

 

TMDL

No TMDL Found

 

 

 

 

 

 

 

 

APPENDICES

Appendix A – Pollutant Load Export Rates (PLERs)

 

Land Use & Cover1	PLERs (lb./acre/year)
	(TP)	(TSS)	(TN)
AGRICULTURE, HSG A	0.45	7.14	2.59
AGRICULTURE, HSG B	0.45	29.4	2.59
AGRICULTURE, HSG C	0.45	59.8	2.59
AGRICULTURE, HSG D	0.45	91.0	2.59
AGRICULTURE, IMPERVIOUS	1.52	650	11.3
COMMERCIAL, HSG A	0.03	7.14	0.27
COMMERCIAL, HSG B	0.12	29.4	1.16
COMMERCIAL, HSG C	0.21	59.8	2.41
COMMERCIAL, HSG D	0.37	91.0	3.66
COMMERCIAL, IMPERVIOUS	1.78	377	15.1
FOREST, HSG A	0.12	7.14	0.54
FOREST, HSG B	0.12	29.4	0.54
FOREST, HSG C	0.12	59.8	0.54
FOREST, HSG D	0.12	91.0	0.54
FOREST, HSG IMPERVIOUS	1.52	650	11.3
HIGH DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
HIGH DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
HIGH DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
HIGH DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
HIGH DENSITY RESIDENTIAL, IMPERVIOUS	2.32	439	14.1
HIGHWAY, HSG A	0.03	7.14	0.27
HIGHWAY, HSG B	0.12	29.4	1.16
HIGHWAY, HSG C	0.21	59.8	2.41
HIGHWAY, HSG D	0.37	91.0	3.66
HIGHWAY, IMPERVIOUS	1.34	1,480	10.2
INDUSTRIAL, HSG A	0.03	7.14	0.27
INDUSTRIAL, HSG B	0.12	29.4	1.16
INDUSTRIAL, HSG C	0.21	59.8	2.41
INDUSTRIAL, HSG D	0.37	91.0	3.66
INDUSTRIAL, IMPERVIOUS	1.78	377	15.1
LOW DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
LOW DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
LOW DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
LOW DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
LOW DENSITY RESIDENTIAL, IMPERVIOUS	1.52	439	14.1
MEDIUM DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
MEDIUM DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
MEDIUM DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
MEDIUM DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
MEDIUM DENSITY RESIDENTIAL, IMPERVIOUS	1.96	439	14.1
OPEN LAND, HSG A	0.12	7.14	0.27
OPEN LAND, HSG B	0.12	29.4	1.16
OPEN LAND, HSG C	0.12	59.8	2.41
OPEN LAND, HSG D	0.12	91.0	3.66
OPEN LAND, IMPERVIOUS	1.52	650	11.3
1HSG = Hydrologic Soil Group

 

Note: PLER is pollutant load export rate; lb./acre/year is pounds per acre per year; TP is total phosphorus; TSS is total suspended solids; and TN is total nitrogen.

 

 

 

Appendix B – Conceptual Design Sheets

 

[1] https://www.epa.gov/nps/handbook-developing-watershed-plans-restore-and-protect-our-waters

[2] Watersheds are defined by the WBP-tool by using MassGIS drainage sub-basins.

[3]Sources: MassGIS 1999, MassGIS 2001, USGS 2016

[4] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[5] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[6] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[7] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[8] Sources: MassGIS (2015a), MassGIS (2015b), MassGIS (2017a), MassGIS (2017b), MassGIS (2020), MA Department of Revenue Division of Local Services (2016), MassGIS (2005), ArcGIS (2020), MassGIS (2009b), MassGIS (2012), ArcGIS (2020b).

[9] Note: Massachusetts law limits phosphorus in lawn fertilizer.

[10] See Element I for additional monitoring plan information.

[11] The planning level cost estimates, pollutant load reduction estimates, and estimates of the BMP footprint were based off information obtained in the following sources and were also adjusted to 2016 values using the Consumer Price Index (United States Bureau of Labor Statistics 2016): Geosyntec Consultants, Inc. (2014, 2015), King and Hagen (2011), Leisenring, et al. (2014), MassDEP (2016a, 2016b), University of Massachusetts, Amherst (2004), Vorhees (2015, 2016a, 2016b).

[12] O&M costs are based on professional judgement, may vary significantly, and are subject to change.

[13] Estimated costs are AACE Level 4 conceptual level costs and may vary significantly.

[14] Funding needed value does not include annual operation & maintenance costs.

[15]Grants & Financial Assistance: Watersheds & Water Quality | Mass.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Town of Groton, MA

in coordination with

Groton Lakes Association

and the

Great Pond Advisory Committee

 

Cover Photo: Lost Lake Boat Ramp Photo Credit: Geosyntec Consultants, Inc.

 

Acknowledgements

The purpose of a Massachusetts Watershed-Based Plan (WBP) is to organize information about Massachusetts' watersheds and present the information in a format that will enhance the development and implementation of projects to restore water quality and beneficial uses in the Commonwealth. The Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was developed by Geosyntec under the direction of Alex Woodle with funding, input, and collaboration from Groton Lakes Association (GLA) and Great Ponds Advisory Committee (GPAC). This WBP was developed using funds from the Community Preservation Act (CPA) and using the Massachusetts Department of Environmental Protection’s (MassDEP’s) Watershed-Based Planning Tool (WBP Tool).

GLA has a goal of preserving and improving the lakes in eastern Groton, including Lost Lake/ Knops Pond. GLA conducts a variety of volunteer events and has been involved with removal of invasive plants and weeds in the lake.

As a nine-member committee in the Town of Groton, GPAC members work on weed management in the lake and make recommendations to the Select Board. Like the GLA, they deal with issues relating to lake management, including health, safety, water quality, and environmental protection.

The following individuals and organizations have contributed invaluable assistance and support for this project:

Core Stakeholders

Alexander Woodle, member of GPAC and GLA

GPAC

GLA

Grotonwood Camp

Gibbet Hill/Weber Restaurant Group

Groton Country Club

Tom Delaney – Director of Public Works (Groton)

 

Project Team

Alexander Woodle, GPAC, GLA

Adam Questad, PE, Geosyntec Consultants, Inc.

Renee Bourdeau, PE, Geosyntec Consultants, Inc.

Julia Keay, PE, Geosyntec Consultants, Inc.

Emma Williamson, EIT, Geosyntec Consultants, Inc.

 

 

Table of Contents

 

Acknowledgements. i

List of Tables. iv

List of Figures. v

Acronyms and Abbreviations. vi

Watershed-Based Plan Background. 1

Incorporating USEPA’s Nine Elements. 1

1.0         Introduction. 3

1.1 Data Sources. 3

1.2 Goal Statement 3

1.3 Plan Development Process. 4

2.0         Characteristics of Lost Lake and Knops Pond. 4

2.1 Land Use. 7

2.2 Impervious Cover 9

3.0         Assessment of Water Quality. 11

3.1 Water Quality Impairments. 11

3.2 Water Quality Goals. 12

3.3 TMDL Pollutant Load Criteria. 14

4.0         Water Quality Summary (Element A) 14

4.1 Additional Water Quality Information. 14

5.0         Water Quality Goals for Lost Lake and Knops Pond (Element B) 35

5.1 Estimated Pollutant Loads. 35

5.2 Water Quality Goals. 37

6.0         Management Actions to Control Phosphorus (Elements C, D, and E) 39

6.1 BMP Hotspot Map. 41

6.2 Field Watershed Investigation. 45

6.3 Existing Management Measures. 48

6.4 Watershed-Wide BMPs. 48

6.5 Site-Specific BMPs. 51

6.6 Non-Structural BMPs and Watershed Outreach (Category 5) 53

7.0         Schedule and Milestones (Elements F and G) 54

8.0         Success Indicators and Evaluation (Element H) 56

9.0 Monitoring Plan (Element I) 57

10.0      Funding for Future Watershed Planning Phases and Implementation. 60

10.1 Cost Estimate and Pollutant Load Reduction Estimates. 60

10.2 Funding for Proposed Management Measures. 61

11.0      Conclusions. 63

12.0      References. 64

Appendix A – Pollutant Load Export Rates (PLERs) 68

Appendix B – Conceptual Design Sheets. 70

 

 

 

 

List of Tables

Table 1: USEPA’s Nine Elements of Watershed Planning

Table 2-1: General Watershed Information

Table 2-2: Watershed Land Uses

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Table 3-3: Surface Water Quality Classification by Assessment Unit

Table 3-4: Water Quality Goals

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion

Table 4-2: Dry Weather Water Quality Parameters

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites

Table 4-5: Groundwater Nutrient Analysis

Table 4-6: Water Quality Data

Table 4-7: Tributary Water Quality Data

Table 4-8: Well Water Quality Data

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants

Table 5-2: Pollutant Load Reductions Needed

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis

Table 6-2: Slope Stabilization Cost Estimates

Table 6-3: Non-Structural BMPs

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs

Table 10-2: Proposed Structural BMP Priority Matrix

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan

 

 

List of Figures

Figure 2-1: Watershed Boundary Map

Figure 2-2: Watershed Land Use Map

Figure 2-3: Watershed Impervious Surface Map

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations

Figure 4-2: Erosion and Point Source Sampling Locations

Figure 4-3: Groundwater Seepage Sampling Locations

Figure 4-4: Sampling Locations

Figure 4-5: Pore Water Nitrate Concentrations

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations

Figure 4-7: Deep Hole Phosphorus Levels

Figure 4-8: Deep Hole Dissolved Oxygen Levels

Figure 4-9: Deep Hole Chlorophyll-a Levels

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation

Figure 4-11: Tributary Phosphorus Concentrations

Figure 4-12: Sampling Stations

Figure 4-13: Photos from GLA Presentation

Figure 6-1: Proposed BMP Locations

Figure 6-2: BMP Hotspot Map

Figure 6-3: Erosion Off Paved Roads

Figure 6-4: Erosion on Unpaved Roads

Figure 6-5: Typical Ditch Detail

Figure 6-6: Catch Basin Filtration Inlet System

Figure 9-1: Proposed Monitoring Locations

 

 

 

Acronyms and Abbreviations

AACE	Association for the Advancement of Cost Engineering
BMP	Best Management Practice
°C	Celsius
CEI	Comprehensive Environmental, Inc.
cells/mL	cells per milliliter
CPI	Consumer Price Index
DCIA	Directly Connected Impervious Areas
DO	Dissolved Oxygen
USEPA	United States Environmental Protection Agency
ET	Evapotranspiration
FC	Fecal Coliform
FS	Fecal Streptococci
GIS	Geographic Information System
GLA	Groton Lakes Association
GPAC	Great Ponds Advisory Committee
lbs.	pounds
lbs./acre/yr.	pounds per acre per year
lbs./yr.	pounds per year
MassDEP	Massachusetts Department of Environmental Protection
mg/L	milligrams per liter
µg/L	microgram per liter
ml	milliliter
NPS	Nonpoint Source
NRCS	National Resource Conservation Service
O&M	Operation and Maintenance
P	precipitation
PLER	Pollutant Load Export Rate
ppb	parts per billion
QAPP	Quality Assurance Project Plan
QA/QC	Quality Assurance / Quality Control
R	Runoff Depth
TIA	Total Impervious Area
TKN	Total Kjeldahl Nitrogen
TMDL	Total Maximum Daily Load
TN	Total Nitrogen
tons/year	tons per year
TP	Total Phosphorus
TSS	Total Suspended Solids
USDA	U.S. Department of Agriculture
USGS	U.S. Geological Survey
WBP	Watershed-Based Plan

 

Watershed-Based Plan Background

A Massachusetts Watershed-Based Plan (WBP) organizes information about a Massachusetts watershed and presents the information in a format that supports the development and implementation of projects to restore water quality and beneficial uses. A Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was prepared for the Lost Lake/Knops Pond watershed in the town of Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). There are two main tributaries: Martins Pond Brook and an Unnamed Tributary.

Incorporating USEPA’s Nine Elements

The Lost Lake/Knops Pond Watershed-Based Plan includes nine criteria[1] for restoring waters impaired by nonpoint source (NPS) pollution. In this plan, the criteria will be called Elements A through I. These guidelines set forth by USEPA, highlight important steps in protecting water quality for waterbodies impacted by human activities and include specific recommendations for guiding future development, as well as strategies for reducing the cumulative impacts of NPS pollution on water quality. The nine criteria are as follows:

1. Identify causes and sources of pollution: The plan must identify the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated herein (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in Element B immediately below. Sources that need to be controlled should be identified at the significant subcategory level with estimates of the extent to which they are present in the watershed (e.g., X numbers of dairy cattle feedlots needing upgrading, including a rough estimate of the number of cattle per facility; Y acres of row crops needing improved nutrient management or sediment control; or Z linear miles of eroded stream bank needing remediation).
2. Estimate pollutant loading into the watershed and the expected load reductions: The plan must estimate the load reductions expected for the management measures described under Element C below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time). Estimates should be provided at the same level as in Element A above (e.g., the total load reduction expected for dairy cattle feedlots; row crops; or eroded stream banks).
3. Describe management measures that will achieve load reductions and targeted critical areas: The plan must describe the NPS management measures that will be implemented to achieve the load reductions estimated under Element B above (as well as to achieve other watershed goals identified in this watershed-based plan), and an identification, using a map or a description, of the critical areas in which those measures will be needed to implement this plan.
4. Estimate amounts of technical and financial assistance and the relevant authorities needed to implement the plan: The plan must contain estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, for implementation. As sources of funding, states should consider Section 319 programs, State Revolving Funds, USDA’s Environmental Quality Incentives Program and Conservation Reserve Program, and other relevant federal, state, local, and private funds.
5. Develop an information/education component: An information/education component will enhance public understanding of the project and encourage early and continued public participation in selecting, designing, and implementing the NPS management measures.
6. Develop a project schedule: A schedule for implementing the NPS management measures identified in this plan will be established.
7. Describe the interim, measurable milestones: The plan will set forth interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented.
8. Identify indicators to measure progress: The plan will include set of criteria to determine whether loading reductions are being achieved over time and whether substantial progress is being made towards attaining water quality standards. In the case that reductions are not achieved, or progress is not made, criteria will also be established for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised.
9. Develop a monitoring component: A monitoring component will evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under Element H immediately above.

The primary goal of this WBP is to assess the Lost Lake/Knops Pond watershed and provide a plan for implementing actions that will result in measurable improvements in water quality. To achieve this goal, this WBP was developed to include the following nine elements in conformance with USEPA guidance discussed above.

Table 1: USEPA’s Nine Elements of Watershed Planning

Element	Plan Section	Element Description
A	4.0	Identify causes and sources of pollution
B	5.0	Estimate pollution load reductions needed for restoration
C	6.0	Identify actions needed to reduce pollution
D	6.0	Estimate costs and authority to implement restoration actions
E	6.0	Implement outreach and education to support restoration
F	7.0	Restoration schedule
G	7.0	Milestones—interim measures to show implementation progress
H	8.0	Success indicators and evaluation—criteria to show restoration success
I	9.0	Monitoring plan

 

1.0       Introduction

The Lost Lake/Knops Pond WBP describes water quality conditions, watershed characteristics, and sources of phosphorus loading to Lost Lake/Knops Pond. The WBP also establishes water quality goals, proposes best management practices (BMPs) for reducing nutrient loading, and estimates associated costs.

The overall goals of the Lost Lakes/Knops Pond WBP are as follows:

• Identify and quantify sources of nutrient loading to the lake
• Establish water quality goal(s) for the watershed
• Propose BMPs to reduce nutrient loading

The adaptive management approach described in the plan allows project partners flexibility in implementing BMPs. Additionally, the plan recognizes that improvements in water quality cannot be achieved with a single BMP and that results are typically not immediate. The proposed water quality monitoring will help guide the approach and quantify the impacts of implemented BMPs.

1.1 Data Sources

This WBP was developed using data sources provided by the Massachusetts Department of Environmental Protection (MassDEP). Additional data sources were reviewed and are described in subsequent sections of this WBP and listed below:

• Lost Lake Watershed Management Plan (ESS Group Inc. 2017)
• Aquatic Vegetation Program 2017 Annual Report, Solitude Lake Management (Solitude 2017)
• Lost Lake Water Quality Investigation Report, Comprehensive Environmental, Inc. (CEI 2013)
• A Diagnostic/Feasibility Study for the Management of Lost Lake/ Knopps [sic] Pond (Baystate Environmental Engineers 1989)
• Lost Lake/Knops Pond Resources Management Plan (GLA 2012)
• Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

1.2 Goal Statement

The long-term goal of this WBP is to reduce total phosphorus (TP) and other nutrient and sediment loadings to Lost Lake/Knops Pond. These pollutant load reductions may result in improvements to water quality conditions in Lost Lake/Knops Pond, as well as reducing the occurrence of eutrophication.

This goal will be accomplished primarily through installation of BMPs to capture runoff while reducing erosion and related nutrient and sediment loading to Lost Lake/Knops Pond from areas near the lake and from its two main tributaries. BMPs are proposed at multiple locations throughout the watershed.

1.3 Plan Development Process

This WBP was developed through collaboration during project management team meetings and conference calls primarily between Geosyntec, Alexander Woodle, and other members of GPAC and GLA.

An iterative process was used to develop the WBP, as outlined below:

• The Project Team (from Geosyntec Consultants, Inc.) first collected and reviewed existing data from the GLA and the GPAC and other available sources.
• A meeting was held on August 12, 2021 to solicit input and information about the Lost Lake/Knops Pond watershed and to identify possible sources of pollution, existing BMP projects, potential BMP opportunity locations, water quality goals, and public outreach activities.
• The Project Team then visited the site on August 30, 2021 to gather data on problem areas and potential BMP opportunity sites.
• A meeting was held on October 21, 2021 to update stakeholders regarding the site visit and to solicit feedback on proposed strategies to improve the water quality within the watershed.
• A WBP was drafted and reviewed by GPAC and GLA.
• The WBP was finalized based on GPAC and GLA input.

2.0       Characteristics of Lost Lake and Knops Pond

This WBP was prepared for the Lost Lake/Knops Pond watershed, in Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). The watershed is mostly forested, with low density residential areas near the lake and agricultural land use in the northwest portion of the watershed. Historically, the land use in the watershed was predominantly agricultural, especially in the northwestern part of the watershed near Martins Brook Pond. Now, activities in the watershed are mostly recreational (e.g., boating, swimming, and fishing on the lake) and agricultural (small farms in the northwest part of the watershed).

Lost Lake and Knops Pond, collectively referred to as Lost Lake/Knops Pond is one water body with two parts. The Lost Lake is the northern section and Knops Pond is the southern section. They join at the area between Ridgewood Road and Radio Road.

There are two main inlets to the lake: Martins Brook that discharges from Martins Brook Pond into the north of the lake and a shorter unnamed tributary that discharges into the west side of the lake. The lake discharges into Whitney Pond to the northeast.

Table 2-1 presents the general watershed information for the Lost Lake/Knops Pond watershed[2] and Figure 2-1 includes a map of the watershed boundary (Mass Geographic Information Systems (GIS) 2001).

Table 2-1: General Watershed Information

Watershed Name (Assessment Unit ID):	Lost Lake/Knops Pond (MA84084)
Major Basin:	Merrimack
Watershed Area:	3,099.3 acres
Water Body Size:	186 acres

Figure 2-1: Watershed Boundary Map[3]

Ctrl + Click on the map to view a full-sized image in your web browser

 

2.1 Land Use

Land use in the Lost Lake/Knops Pond watershed is mostly forested and accounts for approximately 65 percent (%) of the watershed; approximately 12% of the watershed is low density residential; approximately 9% of the watershed is water; approximately 7% of the watershed is agriculture; approximately 4% of the watershed is open land; approximately 2% of the watershed is high density residential; approximately 1% of the watershed is medium density residential; less than 1% of the watershed is commercial or industrial; and 0% of the watershed is designated as highway (Table 2-2; Figure 2-2). Roadways are included in the residential percentages.

A large portion of the residential area is located around Lost Lake/Knops Pond. The area is mostly low density residential, with more developed areas to the northeast of the lake, off Lost Lake Drive. There is a large, forested area north of the lake and agricultural areas (small farms, including cattle and horse farms) in the northwest portion of the watershed.

Table 2-2: Watershed Land Uses

Land Use	Area (acres)	Percent of Watershed
Forest	2,010	64.9
Low Density Residential	383	12.3
Water	285	9.2
Agriculture	204	6.6
Open Land	113	3.6
High Density Residential	51	1.7
Medium Density Residential	31	1.0
Commercial	22	0.7
Highway	0	0.0
Industrial	0	0.0

 

Figure 2-2: Watershed Land Use Map[4]

Ctrl + Click on the map to view a full-sized image in your web browser

2.2 Impervious Cover

There is a strong link between impervious land cover and stream water quality. Impervious cover includes surfaces that prevent the infiltration of water into the ground, such as paved roads and parking lots, roofs, and basketball courts. Most of the impervious cover in the watershed is associated with roads (Figure 2-3).

Impervious areas that are directly connected (DCIA) to receiving waters (via storm sewers, gutters, or other impervious drainage pathways) produce higher runoff volumes and transport stormwater pollutants with greater efficiency than disconnected impervious areas, which are surrounded by vegetated, pervious land. Runoff from disconnected impervious areas is reduced as stormwater flows across adjacent pervious surfaces and infiltrates.

Estimated DCIA for the watershed was calculated using Sutherland equations. USEPA provides guidance (USEPA 2010) on the use of these equations to predict relative levels of connection and disconnection based on the type of stormwater infrastructure within the total impervious area (TIA) of a watershed. Within each subwatershed, the total area of each land use was summed and used to calculate the percent TIA. The estimated TIA and DCIA for the Lost Lake/Knops Pond watershed is 5.7% and 3.6%, respectively.

Although the estimated TIA in the Lost Lake/Knops Pond watershed falls in the 0% and 10% range that typically denotes high quality, this estimation does not account for erosion on unpaved roads or on the slopes of paved roads, that has led to pollution within the lake. The relationship between TIA and water quality can generally be categorized as shown in Table 2-3 (Schueler et al. 2009):

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality (Schueler et al. 2009)

Percent Watershed Impervious Cover	Stream Water Quality
0–10	Typically, high quality, and typified by stable channels, excellent habitat structure, good to excellent water quality, and diverse communities of fish and aquatic insects.
11–25	Clear signs of degradation. Elevated storm flows begin to alter stream geometry, with evident erosion and channel widening. Stream banks become unstable, and physical stream habitat is degraded. Stream water quality shifts into the fair/good category during storms and dry weather. Stream biodiversity declines to fair levels, with most sensitive fish and aquatic insects disappearing from the stream.
26–60	Typically, no longer supportive of a diverse stream community. The stream channel becomes highly unstable, and many stream reaches experience severe widening, downcutting, and streambank erosion. Pool and riffle structure needed to sustain fish is diminished or eliminated and the substrate no longer provides habitat for aquatic insects or spawning areas for fish. Biological quality is typically poor, dominated by pollution tolerant insects and fish. Water quality is consistently fair to poor, and water recreation is often no longer possible due to high bacteria levels.
>60	These streams are typical of “urban drainage,” with most ecological functions greatly impaired or absent, and the stream channel primarily functioning as a conveyance for stormwater flows.

 

Figure 2-3: Watershed Impervious Surface Map[5]

Ctrl + Click on the map to view a full-sized image in your web browser

3.0       Assessment of Water Quality

The goals of this WBP are founded upon the State’s water quality goals and criteria, which specify the indicators by which water quality improvements are measured. This section is an overview of the standards and criteria that apply to Lost Lake/Knops Pond.

3.1 Water Quality Impairments

Known water quality impairments are documented in MassDEP’s 2016 Massachusetts Integrated List of Waters (MassDEP 2019). The impairment categories from this document are set forth in Table 3-1, and water quality impairments are listed in Table 3-2.

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Integrated List Category	Description
1	Unimpaired and not threatened for all designated uses
2	Unimpaired for some uses and not assessed for others
3	Insufficient information to make assessments for any uses
4	Impaired or threatened for one or more uses, but not requiring calculation of a Total Maximum Daily Load (TMDL), including: 4A: TMDL is completed 4B: Impairment controlled by alternative pollution control requirements 4C: Impairment not caused by a pollutant—TMDL not required
5	Impaired or threatened for one or more uses and requiring preparation of a TMDL

 

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Assessment Unit ID	Waterbody	Integrated List Category	Designated Use	Impairment Cause	Impairment Source
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Atmospheric Deposition—Toxics
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Source Unknown
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Eurasian Water Milfoil, Myriophyllum spicatum[6]	Introduction of Nonnative Organisms (Accidental or Intentional)
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Nonnative Aquatic Plants[7]	Introduction of Nonnative Organisms (Accidental or Intentional)

 

3.2 Water Quality Goals

Water quality goals may be established for many purposes, including the following:

1. Forwater bodies with known impairments, aTotal Maximum Daily Load (TMDL) is established by MassDEP and USEPA as the maximum amount of the target pollutant that the waterbody can receive and still safely meet water quality standards. If the waterbody has a TMDL for total phosphorus (TP), total nitrogen (TN), or total suspended solids (TSS), that information is provided below and included as a water quality goal.
2. Forwater bodies without a TMDL for TP, a default water quality goal for TP is based on target concentrations established in theQuality Criteria for Water (USEPA 1986; also known as the “Gold Book”). The Gold Book states that TP should not exceed 50 micrograms per liter (µg/L) in any stream at the point where it enters any lake or reservoir, nor 25 µg/L within a lake or reservoir. For the purposes of developing WBPs, MassDEP has adopted a TP target of 50 µg/L for all streams at their downstream discharge point, regardless of which type of water body the stream discharges to.
3. Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013) prescribe the minimum water quality criteria required to sustain a waterbody’s designated uses. Lost Lake/Knops Pond is a Class B waterbody. The water quality goal for fecal coliform bacteria is based on the Massachusetts Surface Water Quality Standards.

Table 3-3: Surface Water Quality Classification by Assessment Unit

Assessment Unit ID	Waterbody	Class
MA84084	Lost Lake/Knops Pond	B

 

1. Other water quality goals set by the community(e.g., protection of high-quality waters, in-lake phosphorus concentration goal to reduce recurrence of cyanobacteria blooms).

Table 3-4 shows the pollutant and associated water quality goals. For TP, there is no Nonnative Aquatic Plants TMDL for Lost Lake/Knops Pond (although there is a Mercury in Fish Tissue TMDL); therefore, we are using standards from the Gold Book as described in part b above.

Table 3-4: Water Quality Goals

Pollutant

Goal

Source

Total Phosphorus (TP)	Total phosphorus should not exceed: 50 µg/L in any stream 25 µg/L within any lake or reservoir	Quality Criteria for Water (USEPA 1986)
Bacteria	Class B Standards • Public Bathing Beaches: For E. coli, geometric mean of five most recent samples shall not exceed 126 colonies/100 ml and no single sample during the bathing season shall exceed 235 colonies/100 ml. For enterococci, geometric mean of five most recent samples shall not exceed 33 colonies/100 ml and no single sample during bathing season shall exceed 61 colonies/100 ml. • Other Waters and Nonbathing Season at Bathing Beaches: For E. coli, geometric mean of samples from most recent six months shall not exceed 126 colonies/100 ml (typically based on min. 5 samples) and no single sample shall exceed 235 colonies/100 ml. For enterococci, geometric mean of samples from most recent 6 months shall not exceed 33 colonies/100 ml, and no single sample shall exceed 61 colonies/100 ml.	Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013)

Note: There may be more than one water quality goal for bacteria due to different Massachusetts Surface Water Quality Standards Classes for different Assessment Units within the watershed.

The section below summarizes the findings from the Water Quality Assessment Reports that relate to water quality and impairments. Select excerpts from these documents relating to the water quality in the watershed are included below. (Note that relevant information is included directly from these documents for informational purposes and has not been modified.)

Merrimack River Watershed 2004 Water Quality Assessment Report (MA84084 - Lost Lake/Knops Pond)

Four non-native aquatic plant species (Trapa natans, Myriophyllum spicatum, Cabomba caroliniana, Potamogeton crispus) have been reported in Lost Lake/Knops Pond. The Aquatic Life Use is assessed as impaired based on the presence of non-native aquatic plants. Cause(s) of Impairment: Non-Native Aquatic Plants, Eurasian Water Milfoil (Myriophyllum spicatum) Source(s) of Impairment: Introduction of Non-Native Organisms MassDEP DWM biologists collected fish from the pond in May 2004 and composite samples of edible fillets were analyzed for As, Cd, Hg, Pb, Se, PCBs and organochlorine pesticides. MA DPH has issued a fish consumption advisory due to mercury contamination for Lost Lake/Knops Pond. Children younger than 12 years of age, pregnant women, women of childbearing age who may become pregnant, and nursing mothers should not eat any Largemouth Bass fish from this water body. The public should limit consumption of Largemouth Bass fish to two meals per month. Cause(s) of Impairment: Mercury in Fish Tissue Source(s) of Impairment: Atmospheric Deposition - Toxics, Source Unknown Insufficient data were available to assess the Primary Contact Recreational Use. Insufficient data were available to assess the Secondary Contact Recreational Use. Insufficient data were available to assess the Aesthetics Use. Report Recommendations: Conduct monitoring to confirm the presence of non-native aquatic plants.

 

3.3 TMDL Pollutant Load Criteria

Due to the Mercury in Fish Tissue impairment, Lost Lake/Knops Pond is subject to a Regional Mercury TMDL, linked below.

• Northeast Regional Mercury Total Maximum Daily Load

The Lost Lake/Knops Pond watershed does not have a TMDL for non-native plants. MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for the Eurasian Water Milfoil (Myriophyllum spicatum) and Non-Native Aquatic Plants impairments as the impairments are nonpollutants (MassDEP 2019).

4.0       Water Quality Summary (Element A)

In addition to the water quality data discussed in Section 3, above, multiple studies have been conducted for Lost Lake/Knops Pond. Additionally, multiple methods to control invasive plant growth have been implemented, including those described in the 2012 Lost Lake/Knops Pond Resources Management Plan (GLA 2012) and the 2017 Aquatic Vegetation Management Program Annual Report for Lost Lake/Knops Pond (Solitude 2017). A detailed timeline of invasive aquatic plant control methods used is included in Section 6.  

4.1 Additional Water Quality Information

Additional water quality data and information collected from the Knops Pond/Lost Lake watershed from 1988 through 2017 is described below (ESS Group 2017, CEI, Inc. 2013, Baystate Environmental Engineers 1989, GLA 2014).

4.1.1 Lost Lake Watershed Management Plan (ESS Group, Inc. 2017)

This report describes pollutant and nutrient levels from natural and manmade sources in the Lost Lake/Knops Pond watershed. Results and conclusions from the report are summarized below:

• Sampling Locations. The sampling locations for TSS and point sources, other water quality parameters, and sediment are shown in Figure 4-1. The sampling locations for erosion (stormwater runoff) and point sources are shown in Figure 4-2. The groundwater seepage sampling locations are shown in Figure 4-3.
• Sampling Dates. Sampling was conducted on September 9, October 6, and November 16, 2016.
• Sediment Loading. Six locations were sampled for sediment loading (inlets, outlet, and three sites experiencing erosion), and the results are shown in Table 4-1. Parameters sampled included TSS, pH, specific conductance, salinity, temperature, dissolved oxygen (DO), and turbidity. The report found relatively high TSS levels at the locations experiencing erosion (170, 47, and 100 mg/L at TP-2, TP-3, and TP-4, respectively) compared to the low levels at the outlet (<5.0 milligrams per liter [mg/L]). These findings indicate that sediment settles in the lake and does not exit at the outlet. Additionally, the report states the low TSS values observed at the inlets to the lake (6 and <5.0 mg/L respectively for Inlet 1 and Inlet 2) indicated the sediment settles out before entering the lake.
• Dry Weather Sampling. Seven locations (inlets, outlet, and surface and bottom of both sides of Lost Lake/Knops Pond) were sampled for TP, dissolved phosphorus, nitrite-N, nitrate-N, total Kjeldahl nitrogen (TKN), total nitrogen, and TSS during dry weather. The results of this effort are shown in Table 4-2. The report indicated relatively high concentrations of phosphorus at the inlets (compared to the surface and bottom of Lost Lake/Knops Pond), suggesting large phosphorus sources from within the watershed. The report also stated that low DO concentrations indicated the presence of increased organics, decomposition, and algal growth and subsequent decay that may have been caused by excessive nutrients. The low DO concentrations can also create conditions that are favorable for release of sediment-bound phosphorus in the lake sediment, depending on how the phosphorus is bound.
• Water Profiles at Deepest Locations. Water profiles were collected at the deepest locations in Lost Lake/Knops Pond (Table 4-3). The report stated that water quality profiles indicate that water below 1.5 meters was not capable of supporting a healthy fish community in Lost Lake (the northern portions of Lost Lake/Knops Pond); however, the DO concentrations were suitable in Knops Pond (the southern portions of the waterbody).
• Wet Weather Sampling. The wet weather point source and erosion sampling (stormwater runoff at locations experiencing erosion) results from six stormwater samples are shown in Table 4-4. Water quality data includes TP, dissolved phosphorus, nitrate-N, TKN, flow, TSS, pH, specific conductivity, salinity, temperature, DO, and turbidity results at the inlets, outlet, and four locations experiencing erosion. The report stated that data from the roadway stormwater runoff indicated that shoreline erosion is occurring and that sediments containing nutrients are subsequently entering the lake. The high nutrient load in the sediments is indicated by the high phosphorus concentrations measured at the erosional sites. The report also stated the specific conductivity results indicated the sand and sediment are of more concern to water quality than road de-icing agents, although this may change seasonally.
• Groundwater Sampling. Lastly, groundwater nutrient concentrations and rate of seepage are shown in Table 4-5. The report stated that these results indicated that groundwater is entering the lake and that it may also contain nutrients, including dissolved phosphorus. Depending on the installation process of the seepage meters, the nutrients measured may be from the sediments rather than the groundwater itself.
• The measured TSS and concentrations of phosphorus at the sites experiencing erosion and inlets during sediment loading sampling, dry weather sampling, and wet weather sampling indicate that erosion, and specifically the associated phosphorus load, are a significant source of phosphorus to the lake and are most likely a contributor of nutrient issues and decreased water quality within the lake.

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations (ESS, 2017).

 

Figure 4-2: Erosion and Point Source Sampling Locations (ESS 2017).

Figure 4-3: Groundwater Seepage Sampling Locations (ESS 2017).

 

 

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion (ESS 2017).

Note: mg/L is milligrams per liter; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is part per trillion; C is degrees Celsius; % is percent; mg/L is milligrams per liter; NTU is nephelometric turbidity units.

Table 4-2: Dry Weather Water Quality Parameters (ESS 2017).

Note: SU is standard unit; NTU is nephelometric turbidity units; % is percent, mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius; CFS is cubic feet per second.

 

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond (ESS 2017).

 

Note: m is meters; % is percent; mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius.

 

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites (ESS 2017).

Note: mg/L is milligrams per liter, CFS is cubic feet per second; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is parts per trillion; C is degrees Celsius; % is percent.

Table 4-5: Groundwater Nutrient Analysis (ESS 2017).

Note: mg/L is milligrams per liter; L/m²/day is liters per square meter per day.

4.1.2 Lost Lake Water Quality Investigation Report (CEI 2013)

Limited data was collected from the Deep Hole (deepest point) of Lost Lake in July, August, and September 2013 (1 to 2 samples per location). The Deep Hole sampling results are shown in Figure 4-5 (nitrate concentrations) and Figure 4-6 (nitrate + ammonia concentrations). Pore water sampling locations are shown in Figure 4-4. The pore water sampling results are shown in Figure 4-7 (phosphorus), Figure 4-8 (dissolved oxygen), and Figure 4-9 (chlorophyll-a).

The results for both Deep Hole and pore water sampling locations were compared to 1988/1989 water quality data (measured in the 1989 Diagnostic/Feasibility Study [Baystate Environmental Engineers 1989]). The 2013 report indicated that the data comparison results were inconclusive and that there was no trend in the data. Emerging contaminant data were collected as well; however, the report indicated the data results showed very low levels of several emerging contaminants and limited results associated with wastewater.

The report indicated that phosphorus sampling (shown in Figure 4-10 and Figure 4-11) showed the presence of wastewater, high levels of fertilizer, or other sources due to that fact that many of the phosphorus concentrations exceeded 20 parts per billion (ppb; a rough gauge of good water quality) and even 30 ppb (indicative of watershed issues, especially during a wet summer). However, bacteria were also found, which the report indicated showed the presence of untreated sewage from septic systems or livestock.

Figure 4-4: Sampling Locations (CEI 2013).

Figure 4-5: Pore Water Nitrate Concentrations (CEI 2013).

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations (CEI 2013).

Figure 4-7: Deep Hole Phosphorus Levels (CEI 2013).

Note: ppb is parts per billion.

Figure 4-8: Deep Hole Dissolved Oxygen Levels (CEI 2013).

Note: ppm is parts per million.

Figure 4-9: Deep Hole Chlorophyll-a Levels (CEI 2003).

Note: ppm is parts per million.

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation (CEI 2003).

Figure 4-11: Tributary Phosphorus Levels (CEI 2013).

4.1.3 A Diagnostic / Feasibility Study for the Management of Lost Lake / Knopp’s [sic] Pond (Baystate Environmental Engineers 1989)

This report detailed historic water quality conditions in Lost Lake/Knops Pond and identified the major sources of nutrient loadings in 1989, which may or may not reflect current conditions. The report findings are summarized below:

• Sampling Locations. Figure 4-12 shows water quality sampling locations KP-1 (inlet from unnamed tributary), KP-2 (inlet from Martins Pond Brook), and KP-3 through KP-7 (distributed throughout Lost Lake/ Knops Pond).
• Sampling Results. Water quality sampling results are shown in Table 4-6. The study indicated that results suggested Martin’s Pond Brook was a major source of phosphorus loading and that the phosphorus remineralization under anoxic bottom conditions was not an important source to the lake. The study indicated the orthophosphate data results indicate that the pond is mesotrophic. Ammonia levels were highest during the winter and late fall, which according to the study indicated that organic material was decomposing.
• Tributary Sampling Results. Tributary water quality data was shown in Table 4-7. The results indicated that the Gibbet Hill tributary was an important source of nitrogen and phosphorus and may have led to the high nutrient levels in Martin’s Pond Brook. Additionally, the report indicated that the high density of residences near the lake was a potential source of nutrients.
• Well Water Sampling Results. The well water quality data are shown in Table 4-8. The study indicated that bacteria sampling results showed that septic systems were not responsible for the bacteria counts. It also indicated that bacteria counts were most likely due to wildlife, based on the fecal coliform (FC) to fecal streptococci (FS) ratios.
• Nutrient Loading. Additionally, the study calculated nutrients loads based on sampling data and typical export coefficients for sources in Lost Lake/Knops Pond, including the Unnamed Tributary, Martin’s Pond Brook, “Redwater” (shown in Figure 4-12), groundwater (direct input), atmospheric deposition (direct input), bird inputs (direct input), and internal load (anoxic loading). The results of this nutrient load table (shown in Table 4-9) indicated that approximately 63% of the phosphorus load and 51% of the nitrogen load were from the two inlets.
• Overall, the study indicated most of the phosphorus loading (approximately 63%) was from the two inlets, with most from the inlet to Martins Pond Brook. These results concur with the conclusions from the 2013 and 2017 study, which both identify phosphorus as a nutrient of concern within the watershed, although the 2017 study specifically identifies erosion as a major source.

Figure 4-12: Sampling Stations (Baystate Environmental Engineers 1989).

 

 

Table 4-6: Water Quality Data (Baystate Environmental Engineers 1989).

 

Table 4-7: Tributary Water Quality Data (Baystate Environmental Engineers, 1989).

 

Table 4-8: Well Water Quality Data (Baystate Environmental Engineers 1989).

 

 

 

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond (Baystate Environmental Engineers 1989).

 

 

4.1.4 Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

This presentation by GLA on the topic of erosion and stormwater runoff included photos and locations with moderate to severe erosion due to stormwater runoff. Photos from the presentation are shown in Figure 4-13. The following roads and locations were shown:

·         Alder Road	·         Moose Trail
·         Baby Beach	·         Off Prescott Street
·         Birchwood Avenue	·         Paul Revere Trail and Boat Launch
·         Boathouse Road	·         Point Road
·         Highland Road	·         Radio Road
·         Intersection of Pine and Paul Revere Trails	·         Redskin Trail
·         Island Road and Island Road Bridge	·         Shelters Road
·         Juniper Point	·         Summit Avenue
·         Lost Lake Drive at Outlet	·         Wenuchias Trail
·         Maplewood Avenue	·         Weymisset Road

 

Figure 4-13: Photos from GLA Presentation (GLA 2014).

From left to right: Boathouse Road, Paul Revere Trail off Pine Trail (Lost Lake Boat Launch), and Alder Road.

5.0       Water Quality Goals for Lost Lake and Knops Pond (Element B)

Water quality goals are a critical component of watershed management plans; they are the “yardstick” by which management success is measured. The water quality goals describe the pollutant load reductions that indicate improvement in the lake’s water quality. The establishment of water quality goals for Lost Lake/Knops Pond was guided by an analysis of water quality data, nutrient load modeling using the WBP tool, and with input from GPAC and GLA.  

5.1 Estimated Pollutant Loads

GIS was used for the pollutant loading analysis. The land-use data (MassGIS 2009b) was intersected with impervious cover data (MassGIS 2009a) and USDA Natural Resources Conservation Service (NRCS) soils data (USDA NRCS, MassGIS 2012) to create a combined land use/land cover grid. The grid was used to sum the total area of each unique land use/land cover type.

The amount of DCIA was estimated using the Sutherland equations as described above, and any reduction in impervious area due to disconnection (i.e., the area difference between TIA and DCIA) was assigned to the pervious D soil category for that land use to simulate that some infiltration will likely occur after runoff from disconnected impervious surfaces passes over pervious surfaces.

Pollutant loading for key nonpoint source pollutants in the watershed was estimated by multiplying each land use/cover type area by its pollutant load export rate (PLER). The PLERs are an estimate of the annual total pollutant load exported via stormwater from a given unit area of a particular land cover type. The PLER values for TN, TP, and TSS were obtained from USEPA (Voorhees 2016b; see documentation provided in Appendix A) as follows:

L_n = A_n * P_n

Where L_n = Loading of land use/cover type n in pounds per year (lbs./yr.); A_n = area of land use/cover type n (acres); P_n = pollutant load export rate of land use/cover type n in pounds per acre per year (lbs./acre/yr.).

Table 5-1 presents the estimated land-use based TP, TN, and TSS within the Lost Lake/Knops Pond watershed. The largest contributor of land-use based TP, TN, and TSS load originates from areas designated as forested. TP and TN generated from forested areas is generally a result of natural processes such as decomposition of leaf litter and other organic material; the forested portions of the watershed therefore are unlikely to provide opportunities for nutrient load reductions through BMPs. Low density residential areas (including roads) are the second largest contributors of land-use based TP, TN, and TSS load in the watershed. Residential areas provide excellent opportunities for nutrient load reductions through BMPs, as described in the following sections.

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants.

Land Use Type	Pollutant Loading1
	TP (lbs./yr.)	TN (lbs./yr.)	TSS (tons/yr.)

TOTAL	557	3,659	92.13
Forest	299	1,580	61.99
Low Density Residential	87	871	11.96
Agriculture	99	595	8.19
Open Land	27	269	5.18
High Density Residential	23	158	2.34
Commercial	12	109	1.36
Medium Density Residential	9	72	1.04
Industrial	1	6	0.07
Highway	0	0	0.00
1These estimates do not consider loads from point sources or septic systems. Note: TP is total phosphorus; TN is total Nitrogen; TSS is total suspended solids; and lbs./yr. is pounds per year.

 

It is important to note that pollutant loads presented in Table 5-1 do not consider loads from point sources or septic systems. In the Lost Lake/Knops Pond watershed, septic systems have been identified as a potential source of pollutant loading since they are used throughout the watershed. Septic system sources should be separately evaluated to determine whether septic system upgrades or sanitary sewer system conversion would cost-effectively reduce bacteria and nutrient sources in the watershed.

5.2 Water Quality Goals

Many methodologies can be used to set pollutant load reduction goals for a WBP. Goals can be based on water quality criteria, surface water standards, existing monitoring data, existing TMDL criteria, or other data. As discussed in Element A, water quality goals for this WBP are focused on reducing nutrient (TP and TN) and sediment (TSS) loads to Lost Lake/Knops Pond. The water quality goals, and corresponding required loading reductions are included in Table 5-2.

Water quality goals for primary NPS pollutants are listed in Table 5-2 based on the following:

• TMDL water quality goals are used if a TMDL exists for the water body.
• For all water bodies, including impaired waters with a pathogen TMDL, the water quality goal for bacteria is based on theMassachusetts Surface Water Quality Standards (314 CMR 4.00 2013) that apply to the Water Class of the selected water body.
• If the water body does not have a TMDL for TP, a default target TP concentration is provided which is based on guidance provided in the Gold Book. Because there are no similar default water quality goals for TN and TSS, goals for these pollutants are provided in Table 5-2 only if a TMDL exists or alternate goal(s) have been optionally established by the WBP author.
• According to the Gold Book, total phosphorus should not exceed 50 µg/L in any stream at the point where it enters any lake or reservoir. The water quality loading goal was estimated by multiplying this target maximum phosphorus concentration (50 µg/L) by the estimated annual watershed discharge for the selected water body. To estimate the annual watershed discharge, the mean flow was used, which was estimated based on United States Geological Survey (USGS) “Runoff Depth” estimates for Massachusetts (Cohen and Randall 1998). This document provides statewide estimates of annual Precipitation (P), Evapotranspiration (ET), and Runoff depths ® for the northeastern United States. According to their method, R is defined as all water reaching a discharge point (including surface and groundwater) and is calculated by:

P – ET = R

A mean R was determined for the watershed by calculating the average value of R within the watershed boundary. This method includes the following assumptions/limitations:

1. For lakes and ponds, the estimate of annual TP loading is averaged across the entire watershed. However, a given lake or reservoir may have multiple tributary streams, and each stream may drain land with vastly different characteristics. For example, one tributary may drain a highly developed residential area, while a second tributary may drain primarily forested and undeveloped land. In this case, one tributary may exhibit much higher phosphorus concentrations than the average of all streams in the selected watershed.
2. The estimated existing loading value only accounts for phosphorus due to stormwater runoff. Other sources of phosphorus may be relevant, particularly phosphorus from on-site wastewater treatment (septic systems) close to receiving waters. Phosphorus does not typically travel far within an aquifer, but in watersheds that are primarily unsewered, septic systems and other similar groundwater-related sources may contribute a significant load of phosphorus that is not captured in this analysis. As such, it is important to consider the estimated TP loading as “the expected TP loading from stormwater sources.”
3. If the calculated water quality goal is higher than the existing estimated total load, the water quality goal is automatically set equal to the existing estimated total load.

The WBP tool calculates an estimated TP load of 557 lbs./yr. and a water quality goal of 557 lbs./yr. of TP. This would mean that the required load reduction is 0 lbs./yr. to meet the water quality goal. However, the estimated pollutant load and water quality goal do not account for nutrient load from the observed erosion (the soil may be nutrient-rich due to historical agricultural use), septic systems, waterfowl, atmospheric, and/or internal load. The pollutant load also does not account for current land use (e.g., recent development) as the model uses an older land use dataset (2016). Furthermore, observations of roadway erosion and eutrophication throughout the watershed during the site visit indicate that a reduction in nutrient load is required to improve water quality in Lost Lake/Knops Pond.

Therefore, a load reduction of 10% of the existing estimated total load of TP, TN, and TSS is proposed as the required load reduction. Modifications to the required load reduction would be made based on the results of the water quality monitoring program.  

The following adaptive sequence is recommended to sequentially track and meet these load reduction goals:

1. Establish a short-term reduction goal to reduce land-use-based TP, TN, and TSS by 10%. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons per year (tons/yr.) for TP, TN, and TSS, respectively.
2. Implement a baseline water quality monitoring program in accordance with Element I. Results from the monitoring program should advise if Element C BMPs have been effective at addressing listed water quality impairments or water quality goals. Results can further be used to create, periodically inform, or adjust load reduction goals.
3. Establish a long-term reduction goal to reduce land-use-based TP, TN, and TSS over the next 15 years based on monitoring data.

Table 5-2: Pollutant Load Reductions Needed.

Pollutant	Existing Estimated Total Load	Water Quality Target	Required Load Reduction for short-term goal (10%)
Total Phosphorus	557 lbs./yr.	501 lbs./yr.	56 lbs./yr.
Total Nitrogen	3,659 lbs./yr.	3,293 lbs./yr.	366 lbs./yr.
Total Suspended Solids	92 tons/yr.	83 tons/yr.	9 tons/yr.

Note: lbs./yr. is pounds per year.

The proposed BMPs described in this WBP are expected to reduce TP, TN, and TSS loads to Lost Lake/Knops Pond; however, additional BMP implementation/load reduction may be required to meet the water quality goals.

 

6.0       Management Actions to Control Phosphorus (Elements C, D, and E)

The proposed management measures were determined using an iterative process. First, the hotspot map was reviewed, and potential sites located on Town-owned parcels were selected. Next, the field investigation was conducted to assess whether the selected sites are suitable for BMPs and to determine the BMP that best fit site characteristics (e.g., topography, soil type, area). Areas not initially selected were added to the list of potential sites if the area was determined to be suitable for a BMP during the site investigation. After the site investigation, a desktop review was conducted to determine the siting of the BMPs, and the estimated nutrient load reduction based on drainage area and land use. The proposed BMPs were presented to members of the GLA and GPAC during the stakeholder meeting on October 21, 2021. The final proposed BMPs were selected based on feedback from the stakeholder meeting.

Nutrient load reductions for the proposed BMPs were determined using the WBP tool with drainage areas and land use calculated in GIS. The WBP tool also calculates the estimated BMP footprint. The cost estimates for the site-specific BMPs were determined using the initial baseline provided by the WBP tool and adding 30% for design costs, 10% for permitting costs, 10% for project management costs, and 15% for contingency. A 50% contingency was added to represent the maturity level based on the Association for the Advancement of Cost Engineering (AACE) Level 4 cost estimate.

There are two main types of proposed management measures: (1) watershed-wide BMPs that are recommended for implementation throughout the watershed in addition to the key locations specified in this WBP and (2) site-specific BMPs that are recommended for a specific location in the watershed. The proposed management measures are all structural BMPs, except for catch basin cleaning which is a nonstructural or programmatic BMP. Figure 6-1, below, shows the proposed BMP locations.

 

Figure 6-1: Proposed BMP Locations.

6.1 BMP Hotspot Map

BMPs are management measures, activities, and maintenance procedures that prevent or reduce nonpoint source or point source pollution to achieve water quality goals. Examples of BMPs include rain gardens, vegetated swales, and catch basin maintenance. The following points describe the GIS-based analysis conducted within the watershed to identify high priority parcels for BMP implementation:

• Each parcel within the watershed was evaluated based on ten criteria accounting for the parcel ownership, social value, and implementation feasibility (See Table 6-1 for more detail below).
• Each criterion was then given a score from 0 to 5 to represent the priority for BMP implementation based on a metric corresponding to the criterion. (A score of 0 would represent lowest priority for BMP implementation whereas a score of 5 would represent highest priority for BMP implementation.)
• A multiplier was also assigned to each criterion, which reflected the weighted importance of the criterion. (A criterion with a multiplier of 3 had greater weight on the overall prioritization of the parcel than a criterion with a multiplier of 1.)
• The weighted scores for the criteria were then summed for each parcel to calculate a total BMP priority score.

Table 6-1 presents the criteria, indicator type, metrics, scores, and multipliers for this analysis. Parcels with total scores above 60 are recommended for further investigation for BMP implementation suitability.

Figure 6-2 presents the resulting BMP Hotspot Map for the watershed. The following link includes a Microsoft Excel file with information for parcels with a score above 60: hotspot spreadsheet. These parcels are spread out within the watershed and generally are not directly adjacent to Lost Lake/Knops Pond, except for the forested parcels to the northwest of the lake. Additionally, the lack of suitable parcels adjacent to the watershed suggests that proposed BMPs may need to be implemented either in the roadway right-of-way or on smaller parcels of public land, and/or that multiple BMPs may be needed to significantly improve the water quality in the lake. Because several parcels in the northwest portion of the watershed with known current and historic agricultural activities are on the BMP Hotspot map, if monitoring results indicate that agricultural activities are contributing excessive nutrient load to the watershed, BMPs may be implemented in this area.

This analysis solely evaluated individual parcels for BMP implementation suitability and likelihood for the measures to perform effectively within the parcel’s features. This analysis does not quantify the pollutant loading to these parcels from the parcel’s upstream catchment. When further evaluating a parcel’s BMP implementation suitability and cost-effectiveness of BMP implementation, the existing pollutant loading from the parcel’s upstream catchment and potential pollutant load reduction from BMP implementation should be evaluated.

GIS data used for the BMP Hotspot Map analysis included:

• MassGIS (2015a);
• MassGIS (2015b);
• MassGIS (2017a);
• MassGIS (2017b);
• MassGIS (2020);
• Massachusetts Department of Revenue Division of Local Services (2016);
• MassGIS (2005);
• ArcGIS (2020);
• MassGIS (2009b);
• MassGIS (2012); and
• ArcGIS (2020b).

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis.

 

Figure 6-2: BMP Hotspot Map[8]

Ctrl + Click on the map to view a full-sized image in your web browser

6.2 Field Watershed Investigation

Geosyntec conducted a field investigation in the Lost Lake/Knops Pond watershed on August 30, 2021 to identify and confirm sources of pollution and to identify potential BMPs that can be implemented to reduce the pollutant load to Lost Lake/Knops Pond.

Findings from the site visit are described below:

• Birchwood Avenue/Hazelwood Avenue and the “Inlet 2” north of Birchwood Avenue. At this location, erosion was observed along roads and in residential driveways. Here, the stream is small and slow-moving (approximately 3 feet wide with approximately 1-inch-deep flowing water). An observed catch basin on Birchwood Avenue was partially covered with concrete and filled with sediment.
• Off Prescott Road. Here, a dirt road appeared to have been recently regraded.
• Grotonwood Camp At this location, a large parking lot, untreated stormwater runoff appears to concentrate east of the building and discharge into the woods where there was visible erosion. The opportunity exists to implement a stormwater BMP here; this location also has public education and outreach potential. A French drain is also located in this location, which appears to have been more recently installed and collects roof runoff and discharges into the wooded area.
• Martins Pond Brook crossing (culvert) at Martins Pond Road. At this location, catch basin full of sediment was observed.
• Shattuck Street. Here, Martins Pond Road, a dirt road, appears to be contributing sediment to the downstream paved road, where the sediment is entering the catch basins.
• Scarlet Hill Farm (horse farm). Here, the Project Team walked along a portion of the horse farm from Shattuck Street where it abuts Martins Pond Brook; they did not see any evidence of horses having access to the brook.
• Met with John Smigelski at 150 Mill St (Excalibur Farm). John Smigelski showed the Project Team soil sampling data (2011 and earlier years) from his fields off of Groton School Road, which are not within the watershed. The samples indicated elevated levels of TP in the topsoil. John noted that he does not add phosphorus to his soils since the levels are high.
• Lowell Road. Here, it appears that stormwater runoff from Gibbet Hill Grill (restaurant and grazing land) as well as Lawrence Academy discharges to a stormwater pond south of Lowell Road.
• Martin’s Pond Brook crossing (culvert) at Lowell Road. The brook is very slow moving here, and banks are densely vegetated.
• Lost Lake Drive. Here, Martin’s Pond Brook flows through large wetland area. Catch basins along Lost Lake Drive appear to discharge to the wetland.
• Fire Station on Lost Lake Drive. Catch basin with visible sediment buildup on pavement nearby was observed in the driveway; there is the potential for BMP implementation here, though the Project Team suspects that the drainage area is not very large.
• Tavern Road. Erosion was observed on both sides of road; Martins Pond Brook (“Inlet 1”) discharges into the pond east of Tavern Road.
• Boat House Road. Erosion was observed on both sides of road.
• Observed outlet of watershed (beginning of Cow Pond Brook).
• Boat Launch/Fisherman access off of Pine Trail. Erosion and sedimentation were observed in the parking area, as was evidence of sediment loading from Pine Trail down the steep entrance to the parking area. An opportunity to implement a BMP exists at this location. The wetland and pond adjacent to the parking area was stagnant and showed signs of eutrophication
• Highland Road, Radio Road, Weymisset Road, and Island Road. Numerous areas along road and residential driveways with erosion were observed.

Algal blooms, an indication of eutrophication, were present in the ponds that were visited. Locations include off of Radio Road, Tavern Road, the Lost Lake Boat Launch (Pine Trail), and across from Gibbet Hill Grill. These ponds are located throughout the watershed and demonstrate evidence of excessive nutrients.

Erosion on the sides and slopes of paved roads was present throughout the watershed. Loss of vegetation was also noted. The erosion was especially pronounced and of concern on the “esker” roads, located directly adjacent to Lost Lake/Knops Pond. In many cases, this erosion also presented road stability concerns, as road foundations were eroding into the lake. Figure 6-3, below, shows examples of erosion in the watershed.

Figure 6-3: Erosion off Paved Roads.

From left to right, erosion on Island Road, Radio Road, and Pine Trail.

Gullying and channelization were observed on Radio Road and Pine Trail. On the slope of Radio Road, evidence of stormwater runoff flowing directly into Lost Lake/Knops Pond was observed. Loss of vegetation was observed on Island Road and Pine Tail.

Erosion was present on unpaved roads throughout the watershed. Additionally, evidence of regrading (parked equipment and fresh soil) of dirt roads was found on Off Prescott Street. Figure 6-4 shows examples of erosion on unpaved roads.

Figure 6-4: Erosion on Unpaved Roads.

From left to right, erosion on Off Prescott Street, Birchwood Ave, and Shattuck Street.

Gullying and channelization were observed on Birchwood Avenue and Shattuck Street.

Maintenance needs were also observed at several locations during the field investigation. Sediment was found in catch basins at the intersection of Chester Hill and Martins Pond Road, and there are likely other catch basins in the watershed that require cleaning. Additionally, a catch basin on Maplewood Avenue was partially covered by concrete tiles and filled with sediment.

In addition to the field investigation, the Project Team also contacted large land users in the watershed about their land management practices. The findings from the conversations are summarized below:

• Scarlet Hill Farm. This horse farm has a public trail easement. No significant erosion or other sources of nutrients were observed during the site visit. A stream runs adjacent to the public trail.
• Gibbet Hill/Weber Restaurant Group. There are two main land uses on this property: a leased-out 100% organic vegetable farm and a Black Angus cattle farm with 100 acres for grazing, a 2.5-acre field, ½-acre for lamb pasture and ¼-acre for pigs. There is no irrigation.
• Grotonwood Camp. No fertilizer is used at this property. There is an infiltration system for roof drains and no other constructure stormwater management. This land user expressed interest in future partnering on projects.
• Groton Country Club. A phosphorus free fertilizer is applied to the putting greens once a year and to the fairways in the spring. The fertilizer is not applied on open areas or roughs.
• Lawrence Academy. No information was provided. No significant sources of erosion or other sources of nutrients were identified from the road adjacent to the site.
• Excalibur Farm. Although Excalibur Farm is located outside of the watershed, geological and soil attributes at the farm may be like those within the watershed. Soil tests indicate high phosphorus concentrations, although the source may be from the historical agricultural use, soil properties, or other sources.
• Department of Public Works for Town of Groton. Both salt and sand are used on roads within the watershed and on roads directly adjacent to the watershed. The application varies based on the type of storm: for icy storm, sand is used and for storms with less ice, only salt is used. Calcium chloride is often used with the salt. Typically, the roads adjacent to Lost Lake/Knops Pond are salted/sanded once per storm. The applicator machines are calibrated to use the minimum amount of salt and sand needed to provide deicing.

6.3 Existing Management Measures

Existing management measures in Lost Lake/Knops Pond mostly consist of in-lake treatments to control invasive plants. The following timeline show the progression of herbicide treatments:

• 2002: Herbicidal treatment of the entire lake for the control of milfoil was successful in reducing weed growth (GLA 2012).
  • 2003–2004: Spot treatments were conducted to control regrowth (GLA 2012).
• 2003–2011: Limited work was conducted. A weed harvester operated by GLA was used to control new growth (GLA 2012).
• 2011: GLA hired Aquatic Control Technology to conduct a biological survey and propose management alternatives (GLA 2012).
• 2011–2012: GLA continued use of the weed harvester; weed regrowth, specifically of milfoil and Cabomba was intense due to warmer than typical weather (GLA 2012).
• 2017: Herbicide treatment was applied by Solitude Lake Management and focused on areas of dense milfoil, curlyleaf pondweed, and fanwort growth that were identified during a pretreatment survey. Reward (diquot) and Clipper (flumioxazin) were applied to 74 acres (Solitude 2017).
  • Water quality samples were collected, and blue/green cell counts were found to be 540 cells per milliliter (cells/mL), below the Massachusetts Department of Public Health contact threshold of 70,000 cells/mL (Solitude 2017).

Overall, there has been limited success in controlling the invasive plant population in the lake. It should be noted that the algal blooms prevent aquatic plants from growing. If the algal blooms are reduced and the water clarify improves, it is expected that the aquatic plant growth will increase substantially.  

6.4 Watershed-Wide BMPs

The major source of pollution, as determined in past studies and through observations during site investigation, is erosion from unpaved roads and from the slopes of paved roads. Erosion was observed throughout the watershed but is of particular concern around the lake on the “esker” roads. This erosion is both a water quality and safety issue, as the sediment is flowing directly into the lake, carrying nutrients with no attenuation from overland flow, and is eroding from under the road, causing concern regarding the structural integrity of the roads. As such, the watershed-wide BMPs that address erosion (e.g., slope stabilization and dirt road BMPs) should be prioritized. Erosion is also causing many catch basins throughout the watershed to be filled with sediment.

The following watershed-wide BMPs are proposed:

• Slope Stabilization off of Paved Roads. As discussed in the site visit summary, there is severe erosion at many of the paved roads throughout the watershed, especially at the “esker” roads directly adjacent to Lost Lake/Knops Pond. Roads in need of slope stabilization observed during the site visit include Island Road, Radio Road, Weymisset Road, Moose Trail, and Boat House Road, although there may be additional locations for slope stabilization within the watershed. There are several potential methods of slope stabilization, including reseeding with native plants and installing fabric filters (such as jute or geotextiles). While reseeding, it is important to be mindful of limiting fertilizer use, to avoid additional nutrient loading. There are three main components to the slope stabilization: topsoil, hydroseeding (including fertilizer), and an optional erosion control blanket. A cost estimate is shown in Table 6-2.

Table 6-2: Slope Stabilization Cost Estimates

Approximate Site Area (square feet)

Topsoil & Seeding

Topsoil, Seeding, & Erosion Control Blanket

	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)
500	$1,200 ($840 to $1,800)	$2.40  ($1.68 to $3.60)	$2,200  ($1,540 to $3,300)	$4.50 ($3.15 to $6.75)
2,000	$4,800  ($3,360 to $7,200)	$2.40 ($1.68 to $3.60)	$9,000  ($6,300 to $13,500)	$4.50 ($3.15 to $6.75)
10,000	$23,800  ($16,660 to $35,700)	$2.40  ($1.68 to $3.60)	$44,900  ($31,430 to $67,350)	$4.50 ($3.15 to $6.75)
50,000	$119,000 ($83,300 to $178,500)	$2.40  ($1.68 to $3.60)	$224,500 ($157,150 to $336,750)	$4.50  ($3.15 to $6.75)

• Dirt Road BMPs. Many of the dirt roads throughout the watershed showed signs of moderate to severe erosion, including Maplewood Avenue, Birchwood Avenue, Off Prescott Street, and Shattuck Street. The Massachusetts Unpaved Roads BMP Manual (MassDEP 2011) includes a variety of potential dirt road BMPs. Proposed solutions to dirt road erosion include maintaining natural buffers and drainage ways, general shoulder maintenance, and structural measures such as regrading roads, installing waterbars, and lining ditches. Figure 6-5 shows an example of two types of ditches.

 

Figure 6-5: Typical Ditch Detail (MassDEP 2011)

We recommend that GLA and GPAC coordinate with the Town of Groton on any dirt road-related projects or grant proposals.

• Catch Basin Maintenance and Structural BMPs. As described in the site visit summary, many catch basins throughout the watershed were filled with sediment due to erosion, including catch basins located on Maplewood Avenue, Shattuck Street, and Prescott Street. The catch basins should be cleaned in coordination with the Town of Groton. Stabilizing the dirt roads and slopes can help reduce erosion; however, in addition, small collection sumps and/or rain gardens can be installed upstream of drain inlets. The catch basin on Maplewood Avenue was filled with sediment and partially covered with concrete tiles. This catch basin should either be fully covered to prevent sediment from entering the sump and subsequently the drainpipes that discharge to Lost Lake/Knops Pond or opened to receive stormwater runoff. Modifications can also be made to the catch basin inlet and sump to better capture sediment to prevent discharge into the lake or its tributaries. Figure 6-6 shows an example of a catch basin filtration inlet system that removes sediment and oil from stormwater runoff (New Pig 2021).

 

Figure 6-6: Catch Basin Filtration Inlet System (New Pig 2021)

6.5 Site-Specific BMPs

We also identified several site-specific proposed management measures as opportunities to capture and slow runoff and reduce pollutant loading. The six site-specific BMPs are the Grotonwood Camp raingarden, the Boat Launch raingarden, the Boat Launch swale, the Birchwood Road swale, the Shattuck Street lot raingarden, and the Shattuck Street swale. The conceptual design sheets for the proposed BMPs are included as Appendix B. The site-specific BMPs should be implemented in conjunction with the site-specific BMPs, as it is unlikely that the site-specific BMPs alone will provide enough nutrient load removal to resolve the water quality issues within the watershed. The site-specific BMPs are described in more detail below:

• Grotonwood Camp Raingarden. The proposed raingarden will infiltrate stormwater runoff from the Grotonwood Camp main parking lot, a relatively large area of impervious surface for the watershed. Currently, there are signs of erosion at the edge of the forest where the stormwater runoff channelizes from the parking lot. The proposed raingarden would mitigate this erosion and provide stormwater quantity and quality benefits, such as reducing peak flows from the parking lot and reducing the nutrient and sediment load. Although the stormwater runoff does not discharge directly to a tributary or Lost Lake/Knops Pond, it discharges approximately 100 feet from a stream that runs through Grotonwood Camp.
• Boat Launch Raingarden. The proposed boat launch raingarden at the Lost Lake Public Boat Launch will infiltrate stormwater runoff from the boat launch parking lot, which is mostly paved. The Boat Launch Swale, described below, will treat stormwater runoff from the paved road (off Pine Trail) that leads down to the parking lot. Currently, there is significant erosion at the boat launch. Additionally, there is eutrophication in the pond directly adjacent to the boat launch, indicating excessive nutrient loads. Installing a raingarden at the boat launch would infiltrate stormwater runoff, reducing erosion, and mitigate the nutrient load that enters the lake directly.
• Boat Launch Swale. The proposed boat launch swale will work in conjunction with the raingarden described above. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loads from the road leading to the boat launch. The road is paved and moderately steep and there are signs of erosion on either side of it. As the stormwater runoff is already directed towards the sides of the road, installing a swale will provide water quality treatment instead of carrying nutrients and sediment towards the boat launch and subsequently to Lost Lake/Knops Pond, as is currently occurring due to channelized flow.
• Birchwood Avenue Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loading from Birchwood Road. Birchwood Avenue is a paved, steep, winding road with observed erosion at the outer edge where the road curves. The erosion is severe, with defined channels and gullies on the slope of the road. Stormwater runoff from Birchwood Avenue flows into the Unnamed Tributary that leads directly into Lost Lake/ Knops Pond.
• Shattuck Street Lot Raingarden. The proposed Shattuck Street Lot raingarden will infiltrate stormwater runoff from Shattuck Street and part of Scarlet Hill Farm. The proposed location is the parking lot for the public access trails at Scarlet Hill Farm that run adjacent to a stream that is a tributary for Lost Lake/Knops Pond. Although Scarlet Hill Farm has received awards for their manure practices, agricultural land tends to have higher pollutant loads than forested or open land.
• Shattuck Street Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff from Shattuck Street and the surrounding area and mitigate the nutrient loads. Like the Shattuck Street Lot raingarden, the drainage area for the swale also includes agricultural land at Scarlet Hill Farm. In addition, there is severe erosion on Shattuck Street, which is unpaved (gravel) with a moderately steep slope; therefore, installing the swale would reduce the erosion by reducing stormwater runoff and mitigate the associated nutrient load.

More information about the construction and operation and maintenance (O&M) of each type is included below.

Raingardens/Bioretention Areas (MassDEP 2016a):

• Raingardens use soil, plants, and microbes to treat stormwater before it infiltrates into the soil or is discharged. They can provide pollutant removal and infiltrate up to 1 inch of rainfall, in addition to providing groundwater recharge.
• Raingardens are comprised of shallow depressions with a layer of sandy soil, mulch, and planted with dense vegetation. Generally, they are designed to pond to a depth of water 6 to 8 inches deep. The soil mix should be sandy loam or loamy sand with a clay content of less than 15%.
• Soil and any eroded areas should be inspected monthly, and litter and debris should be removed accordingly. Invasive species should be removed as needed and mulch replaced every two years. With proper selection of plants, the need for fertilizers and pesticides should be eliminated or at least very minimal. This is especially important for the Lost Lake/Knops Pond watershed, as introducing additional nutrient loads would be detrimental to water quality and negate the use of the raingarden.

Treatment Swales (MassDEP 2016a):

• Water quality or treatment swales are vegetated open channels that convey runoff and treat the stormwater runoff.
• Soil characteristics, flow capacity, erosion resistance, and vegetation should be considered when designing a treatment swale.
• Swale maintenance includes inspecting swales to ensure vegetation health and lack of erosion (once per month initially, then twice per year); mow if necessary (as needed); remove sediment and debris manually (at least once per year), and re-seed as necessary).

6.6 Non-Structural BMPs and Watershed Outreach (Category 5)

Non-structural BMPs typically do not involve construction and are often more broadly applied throughout a watershed. Implementation of these BMPs can result in significant load reductions. Examples of non-structural BMPs include:

• Municipal “good housekeeping” practices such as street sweeping and leaf litter collection programs can reduce phosphorus loading by reducing transport of pollutants through stormwater systems.
• Regulations can be used to help affect behavior change and manage land uses practices; examples of regulatory tools include stormwater management regulations, septic system ordinances, fertilizer regulations, pet waste removal requirements, and more.
• Outreach and education can also be used to help change behavior and reduce pollutant loading by encouraging and promoting activities that reduce or prevent pollutant loading such as fertilizer reduction incentives, pet waste pick-up programs, pond-friendly landscaping workshops and more.
• Land conservation is a common tool that can be used to prevent loading from land conversion activities.

Table 6-3 summarizes potential non-structural BMPs that can be implemented throughout the watershed.

Table 6-3: Non-Structural BMPs

Non-Structural BMP	Description	Responsible Party
Fertilizer Program	Reduce the amount and frequency of fertilizer application[9] to pervious developed areas throughout the watershed.	Town of Groton; GPAC; GLA
Street Sweeping	Optimize street sweeping locations and frequency equivalent to two times a year sweeping (in Spring and Fall) of 50% of roads within 650-feet of the shoreline, using vacuum assisted sweeper.	Town of Groton
Leaf Litter Management	Provide leaf collection at least 4 times during October and November for properties within 650-feet of the shoreline. Within 24 hours of leaf collection, collect remaining leaf litter on paved streets using a cleaning machine, such as a mechanical broom or vacuum assisted street cleaner.	Town of Groton
Shoreline Buffer	Retrofit developed areas along shoreline with 20-ft-no-mow/no-alteration grassed buffer for properties within 425-feet of the shoreline.	Town of Groton
Regulations	Establish municipal regulations to enable and promote improved stormwater management, buffer protections, and shoreland controls.	Town Planning Staff
Land Conservation	Coordinate with groups to prioritize land conservation goals/target parcels to reduce future load associated with new development.	Town Planning Staff; GPAC; GLA
Impervious Disconnection	Direct runoff from impervious areas such as roadways, parking lots, and roofs, and discharge it to adjacent vegetated permeable surfaces that are of sufficient size with adequate soils to receive the runoff without causing negative impacts to adjacent down-gradient properties.	Town of Groton

Watershed outreach will take place through educational kiosks at the proposed raingardens. These kiosks will include information on water quality in Lost Lake/Knops Pond, the purpose of the stormwater BMPs and their impact on water quality, and actions residents can take to improve water quality in the watershed.

The target audiences include residents in the watershed, recreational users of Lost Lake/Knops Pond (boaters, beach-goers, etc.), and watershed organizations and other user groups (GLA, GPAC, etc.)

GLA and/or GPAC may coordinate with the Town of Groton on distribution of educational materials such as lawn and landscaping education, pet waste management, car washing, and other topics. GLA and/or GPAC may also use their mailing lists to distribute residential educational materials, such as resident pet waste information, septic system handouts, and handouts on residential yard care, found on Think Blue Massachusetts’s website (Think Blue Massachusetts | Residents).

7.0       Schedule and Milestones (Elements F and G)

The project schedule and milestones presented in this section will enable project partners to track management activities over time as the Last Lakes and Knops Pond Watershed-Based Plan is implemented.

Table 7-1 provides a preliminary schedule for implementation of recommendations provided by this WBP. It is expected that the WBP will be reevaluated and updated in 2024, or as needed, based on ongoing monitoring results and other efforts. New projects will be identified through future data analysis, and stakeholder engagement and will be included in updates to the implementation schedule.

 

 

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Structural & Nonstructural BMPs
Slope Stabilization 1 to 2 sites per year	Apply for 604b grant funding to prioritize sites and create conceptual designs.	Apply for Section 319 funding to implement BMPs.	Implement BMPs; Conduct annual maintenance on constructed BMPs; Apply for Section 319 funding for additional sites.
	12/1/2022	12/1/2023	12/1/2024
Dirt Road BMPs 1 road segment per year	Apply for Section 319 or 604b grant funding.	Improve 1 road segment per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Catch Basin Cleaning	Schedule meeting with Town of Groton to discuss catch basin cleaning schedule.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Maintenance	Schedule meeting with Town of Groton to discuss catch basin maintenance.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Inlet/Sump Modification	Apply for Section 319 or 604b grant funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Site-specific BMPs 1-2 per year based on prioritization matrix	Apply for Section 319 funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024

 

Public Education & Outreach
Install Educational Kiosk	Install educational kiosk with BMP construction.
	12/1/2023

 

Monitoring
Monitoring Plan	Conduct four sampling events per year[10].
	Annually

 

8.0       Success Indicators and Evaluation (Element H)

The water quality target concentration(s) is presented under Element A of this plan. To achieve this target concentration, the annual loading must be reduced to the amount described in Element B. Element C of this plan describes the various management measures that will be implemented to achieve this targeted load reduction. The evaluation criteria and monitoring program described below will be used to measure the effectiveness of the proposed management measures (described in Element C) in improving the water quality of Lost Lake/Knops Pond:

• Indirect Indicators of Load Reduction. Indicators of excessive nutrient load include moderate to severe erosion and eutrophication in ponds or in Lost Lake/Knops Pond itself. Therefore, the absence of erosion, especially close to Lost Lake/Knops Pond or its tributaries, and/or the absence of eutrophication will indicate successful load reduction. In addition, nuisance algae and vegetation monitoring in Lost Lake/Knops Pond can also indicate water quality trends.
• Direct Indicators (Measurements) of Load Reduction. Results of the water quality monitoring will also indicate progress towards nutrient load reduction, specifically a reduction in phosphorus in both the Unnamed Tributary and in Martins Pond Brook. See Element I for more information about the water quality monitoring plan.
• Project-Specific Indicators. As previously discussed, the absence of erosion and eutrophication will likely indicate success in reducing the nutrient load. Specifically, areas near constructed watershed-wide or structural BMPs will indicate that these projects are successful.
  • Number of BMPs Installed. Element C of this WBP recommendations the installation of structural BMPs at six locations and recommends several watershed-wide BMPs. The anticipated pollutant load reduction has been documented for each proposed BMP, and the number of BMPs installed will be tracked and quantified as part of this program. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning and slope stabilization).
• TMDL Criteria. Lost Lake/Knops Pond is not currently subject to a non-native aquatic plant TMDL; therefore, this criterion is not applicable. However, please note that Lost Lake/Knops Pond does have a Mercury in Fish Tissue TMDL.

9.0 Monitoring Plan (Element I)

This WBP recommends implementation of a volunteer water quality monitoring program. The purpose of the monitoring program is to refine the location of and quantify sources of pollution. Through previous studies and the site visit, sources of pollution are reasonably well known; however, monitoring would allow for source contributions to be evaluated and quantified spatially. Because this program will help identify priority sources, it will lead to more effective implementation of BMPs. Additionally, monitoring will allow for a quantitative measure of BMP effectiveness by comparing concentrations of TP, TN, and TSS before and after the implementation of BMPs.  Elements of the recommended monitoring plan are summarized below:

• The monitoring plan locations were chosen based on accessibility and proximity to suspected sources of pollution and nutrients. In terms of accessibility, sampling locations were chosen to be close to a road or street and not along steep slopes. An exception is the Martins Pond Brook inlet which may need to be accessed via private property or by boat. The sampling locations chosen are downstream of suspected sources of pollution and nutrients to target areas identified as contributing pollution and nutrients to the watershed, based on previous reports and the site visit. Figure 9-1 shows the proposed monitoring locations. The monitoring locations are described below.
  • Outlet of Martins Pond Brook. This area, currently conservation land, features historical agricultural use. Previous reports have identified Martins Pond Brook as a source of phosphorus (ESS 2017).
  • Martin’s Pond at Lowell Street. This upstream area has historical and current agricultural use (Scarlet Hill Farm). Additionally, the Lowell Street culvert is fairly accessible for sampling.
  • Martins Pond Brook Inlet. The sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations.
  • Unnamed Tributary Inlet. This sampling location was chosen to determine if residential and developed areas are contributing to the phosphorus load.
  • Unnamed Tributary at Boston Road. Like the Martins Pond Brook inlet, this sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations. The road crossing at this location provides accessibility.
• In-Lake Sampling. In-lake sampling is recommended to ensure that the in-lake phosphorus concentration remains below the target concentration of 50 ug/L. Samples could be taken at locations in Lost Lake/Knops Pond, specifically at the deepest locations (at multiple points in the water column) and at areas next to slopes noted for erosion due to stormwater runoff.
• At a minimum, sampling parameters should include TP, dissolved phosphorus, and total suspended solids.
• When to Sample. Sampling should be conducted during both dry and wet weather events to best capture the behavior of sources of pollution. A minimum of two dry and two wet weather events should be conducted annually in the fall, spring, and summer to assess temporal and seasonal trends.
• Quality Assurance/Quality Control (QA/QC). As the results from the volunteer monitoring program will be used for internal guidance only, developing a quality assurance project plan (QAPP) is not required. However, it should be noted that a QAPP is required to submit data to MassDEP and is recommended to help ensure data quality.
• Interpretation of Results/Data Analysis. The results of each sampling location should be compared both to the results of other sampling locations and to results from prior sampling events to determine seasonal trends, temporal trends, and/or the efficacy of any implemented solutions. By comparing the results at sampling locations upstream and downstream of each tributary, sources of pollution may be able to be determined. For example, comparing phosphorus results upstream and downstream of the forested area adjacent to the Martin’s Brook Pond tributary may help to determine if natural sources of phosphorus (i.e., leaf litter) are a large contributor to the overall phosphorus levels.
• Refinement of Monitoring Plan. Potential future changes to the monitoring plan include refining locations to pinpoint specific source areas; collecting runoff sampling from bare soil or agricultural areas if access is provided by the landowners; finger printing of inlet concentrations compared to solid soil data to further refine sources of pollution; additional in-lake or watershed septic source evaluations (e.g., DNA markets, advanced chemical indicators, nutrient isotopes); and additional in-lake monitoring at various depths throughout Lost Lake/Knops Pond.

 

 

Figure 9-1: Proposed Monitoring Locations.

10.0 Funding for Future Watershed Planning Phases and Implementation

10.1 Cost Estimate and Pollutant Load Reduction Estimates

Table 10-1 presents the estimated pollutant load reductions and costs for the proposed management measures.

 

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs[11].

Site-Specific BMP	Drainage Area (ac)	BMP Footprint (sf)/BMP Length (ft)	BMP Design Storm Depth (in)	Estimated Pollutant Removal			Estimated Annual O&M Costs[12]	Estimated Cost
				Total Phosphorus (lbs./year)	Total Nitrogen (lbs./year)	Total Suspended Solids (lbs./year)
Grotonwood Camp Raingarden	0.47	440 sf	0.5	0.5	4.0	191.2	$2,000	$21,200
Boat Launch Raingarden	0.47	405 sf	0.5	0.5	3.6	171.6	$2,000	$21,700
Boat Launch Swale	0.36	50 ft	0.5	0.1	0.1	42.2	$1,000	$12,800
Birchwood Avenue Swale	0.16	40 ft	0.5	0.1	0.2	45.5	$1,000	$5,700
Shattuck Street Lot Raingarden	1.23	445 sf	0.5	0.5	3.2	134.4	$2,000	$56,700
Shattuck Street Swale	0.36	60 ft	0.5	0.1	0.3	84.3	$1,000	$48,800

Note: ac is acres; sf is square feet; lbs./year is pounds per year; O&M is operation and maintenance.

Table 10-2 presents a priority matrix to guide future work and grant funding based on the following criteria:

• Cost/TP Removed. The estimated cost to construct the structural BMP divided by the pounds of total phosphorus removed per year to get a cost per pound of phosphorus removed.
• Cost/TN Removed. The estimated cost to construct the structural BMP divided by the pounds of total nitrogen removed per year to get a cost per pound of nitrogen removed.
• An evaluation of whether adequate space and topographical/geological conditions are available to construct the BMP (e.g., considering slope, soil type).
• Structural BMPs, especially raingardens with educational kiosks, can be used to educate the public about stormwater and water quality. Therefore, the visibility of each proposed structural BMP was considered (e.g., if it is in an often-used space, proximity to road).
• Public/Private. Constructing structural BMPs on public property tends to be more ideal than working with the landowner to install a BMP on private property.
• Proximity to Lake/Tributary. Structural BMPs installed close to the lake or a tributary will prevent nutrients and sediment from directly entering the lake without any attenuation. Therefore, these BMPs are prioritized.

The ranking is on a scale of one to five with five being the most optimal.

Table 10-2: Proposed Structural BMP Priority Matrix.

Structural BMP	Cost/TP Removed	Cost/TN Removed	Feasibility	Visibility	Public/ Private	Proximity to Lake/ Tributary	Sum	Rank
Slope Stabilization	4	4	4	3	5	5	25	High
Dirt Road BMPs	4	4	4	3	5	3	23	High
Catch Basin BMPs	5	5	5	1	5	3	24	High
Grotonwood Camp Raingarden	3	3	4	3	1	1	15	Low
Boat Launch Raingarden	3	1	3	4	5	5	21	High
Boat Launch Swale	5	5	4	3	5	4	26	High
Birchwood Avenue Swale	5	5	3	2	5	3	23	High
Shattuck Street Lot Raingarden	3	3	4	3	1	4	18	Medium
Shattuck Street Swale	4	4	4	2	5	3	22	High

Note: TP is total phosphorus and TN is total nitrogen.

10.2 Funding for Proposed Management Measures

The funding needed to implement the proposed site-specific BMPs (described in Element C) is presented in Table 10-3. The total cost for the program was estimated at $237,000 with estimated annual O&M costs of $14,500 or more. Table 10-3 presents the funding needed to implement the management measures presented in this watershed plan. The table includes costs for BMPs and operation and maintenance activities.

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan.

Management Measures	Location	Capital Costs[13]	Annual O&M Costs	Relevant Authorities	Technical Assistance Needed	Funding Needed[14]
Watershed-wide BMPs (from Element C)
Slope Stabilization - Reseeding	Watershed-wide	$23,800 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$23,800
Slope Stabilization – Reseeding & Fabric Filter	Watershed-wide	$44,900 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$44,900
Dirt Road BMPs	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Cleaning	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Maintenance	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Inlet/Sump Modification	Watershed-wide	$295 each plus labor costs	$1,475 for 5 replacement inserts plus labor	Town of Groton; GLA; GPAC	Permitting and Construction	$1,475 for 5 inserts plus permitting and labor costs
Site-specific BMPs (from Element C)
Bioretention and Rain Garden	Grotonwood Camp Raingarden	$21,216	$2,000	Town of Groton; Grotonwood Camp	Engineering Design and Construction	$21,216
Bioretention and Rain Garden	Boat Launch Raingarden	$21,676	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$21,676
Grassed Channel/Water Quality Swale	Boat Launch Swale	$12,811	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$12,811
Grassed Channel/Water Quality Swale	Birchwood Rd Swale	$5,693	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$5,693
Bioretention and Rain Garden	Shattuck Street Lot Raingarden	$56,727	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$56,727
Grassed Channel/Water Quality Swale	Shattuck Street Swale	$48,753	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$48,753
Information/Education (see Element E)
Monitoring and Evaluation (see Element H/I)
Total Funding Needed:						$237,000
Funding Sources:
MassDEP Section 319 and 604b Grants

11.0 Conclusions

As stated in Section 1.2 of this WBP, the long-term goal is to reduce total phosphorus and other nutrient and sediment loadings to Lost Lake/Knops Pond. The water quality goals (described in Section 5.2) will be accomplished through installation of BMPs throughout the watershed (described in Section 6.0) and will be measured through water quality monitoring efforts (described in Section 9.0). The action items for this WBP are described below.

• BMP Implementation. Implement BMPs throughout the watershed to achieve a 10% reduction in nutrient load as an interim goal. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons/yr. for TP, TN, and TSS, respectively.
• Grant Funding. Apply for MassDEP Section 319 and 604b grants[15] for implementation of BMPs and additional planning, such as determining sites for slope stabilization.
  • Section 319 Nonpoint Source Grant. This program is used for implementation projects that address the prevention, control, and abatement of nonpoint source pollution. Generally, eligible projects must implement measures that target the major source(s) of nonpoint source pollution within a watershed, contain an appropriate method for evaluating the project results, and must address activities identified in the Massachusetts NPS Management Plan.
  • Section 604b Nonpoint Source Grant. This program is used for eligible entities to conduct watershed based nonpoint source assessment and planning projects that result in the following: development of preliminary designs and implementation plans that will address water quality impairments in impaired watersheds, determination of the nature, extent, and causes of water quality problems, and determination of pollutant loads necessary to meet water quality standards.
• Indicators of Success. The monitoring program and other indicators will be used to measure the effectiveness of the implemented BMPs.
  • Monitoring Program (Direct Measurements). Results of the water quality monitoring will indicate progress towards nutrient load reduction.
  • Indirect Indicators. Indirect indicators include the absence of eutrophication in ponds in the watershed and in Lost Lake/Knops Pond and the absence of erosion throughout the watershed. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning).
  • Project Specific Indicators. The number of BMPs installed will be tracked and quantified as part of this WBP.
• Long-Term Goals. The long-term goals will be adapted based on the results of the water quality monitoring and the indicators of success.

 

•  

12.0 References

314 CMR 4.00. 2013. Division of Water Pollution Control, Massachusetts Surface Water Quality Standards. https://www.arcgis.com/home/item.html?id=be2124509b064754875b8f0d6176cc4c.

ArcGIS. 2020a. USA Soils Hydrologic Group. Imagery Layer.

ArcGIS. 2020b. “USA Soils Water Table Depth.” Imagery Layer.

Cohen, A. J. and A. D. Randall. 1998. Mean annual runoff, precipitation, and evapotranspiration in the glaciated northeastern United States, 1951-80. Prepared for United States Geological Survey, Reston VA.

Geosyntec. 2014. Least Cost Mix of BMPs Analysis, Evaluation of Stormwater Standards Contract No. EP-C-08-002, Task Order 2010-12. Prepared for Jesse W. Pritts, Task Order Manager, U.S. Environmental Protection Agency.

Geosyntec. 2015. Appendix B: Pollutant Load Modeling Report, Water Integration for the Squamscott-Exeter (WISE) River Watershed.

 GLA. 2012. Lost Lake/Knops Pond Resource Management Plan. Prepared by Groton Lakes Association. Revision 4.01. August 12, 2012.

King, D. and P. Hagan. 2011. Costs of Stormwater Management Practices in Maryland Counties. University of Maryland Center for Environmental Science Chesapeake Biological Laboratory. October 11, 2011.

Leisenring, M., J. Clary, and P. Hobson. 2014. International Stormwater Best Management Practices (BMP) Database Pollutant Category Statistical Summary Report: Solids, Bacteria, Nutrients and Metals. Geosyntec Consultants, Inc. and Wright Water Engineers, Inc. December 2014.

Massachusetts Department of Revenue Division of Local Services. 2016. Property Type Classification Codes, Non-arm’s Length Codes and Sales Report Spreadsheet Specifications. June 2016.  https://www.mass.gov/files/documents/2016/08/wr/classificationcodebook.pdf

MassDEP. 2001. The Massachusetts Unpaved Roads BMP Manual. Prepared by Berkshire Regional Planning Commission and prepared for Massachusetts Department of Environmental Protection and U.S. Environmental Protection Agency. Winter 2001.

MassDEP. 2012. Massachusetts Year 2012 Integrated List of Waters Final Listing of Massachusetts' Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act.

MassDEP. 2016a. Massachusetts Clean Water Toolkit.

MassDEP. 2016b. Massachusetts Stormwater Handbook, Vol. 2, Ch. 2, Stormwater Best Management Practices.

MassDEP. 2019. Massachusetts Year 2016 Integrated List of Waters Final Listing of Massachusetts’ Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act. December 2019.

MassGIS. 1999. Networked Hydro Centerlines. Shapefile.

MassGIS. 2001. USGS Topographic Quadrangle Images. Image.

MassGIS. 2005. Elevation (Topographic) Data (2005). Digital Elevation Model.

MassGIS. 2007. Drainage Sub-basins. Shapefile.

MassGIS. 2009a. Impervious Surface. Image.

MassGIS. 2009b. Land Use (2005). Shapefile.

MassGIS. 2012. 2010 U.S. Census Environmental Justice Populations. Shapefile.

MassGIS. 2013. MassDEP 2012 Integrated List of Waters (305(b)/303(d)). Shapefile.

MassGIS. 2015a. Fire Stations. Shapefile.

MassGIS. 2015b. Police Stations. Shapefile.

MassGIS. 2017a. Town and City Halls. Layer.

MassGIS. 2017b. Libraries. Layer.

MassGIS. 2020. Massachusetts Schools (Pre-K through High School). Data layer.

MassGIS. 2021. Standardized Assessors’ Parcels. Mapping Data Set.

New Pig. 2021. “PIG® Oil & Sediment Catch Basin Filtration System – Large.” < Storm Drain Filter Insert for Oil & Sediment – New Pig>. Accessed November 19, 2021.

Solitude Lake Management. 2017. Annual Report 2017 Aquatic Vegetation Management Program Lost Lake & Knops Pond. Prepared for Groton Lakes Associated & Town of Groton. December 2017.

Schueler, T.R., L. Fraley-McNeal, and K. Cappiella. 2009. “Is impervious cover still important? Review of recent research.” Journal of Hydrologic Engineering 14 (4): 309-315.

United States Bureau of Labor Statistics. 2016. Consumer Price Index.

United States Geological Survey. 2016. National Hydrography Dataset, High Resolution Shapefile.

University of Massachusetts, Amherst. 2004. Stormwater Technologies Clearinghouse.

USDA NRCS and MassGIS. 2012. NRCS SSURGO-Certified Soils. Shapefile.

USEPA. 1986. “Quality Criteria for Water (Gold Book).” EPA 440/5-86-001. Office of Water, Regulations and Standards. Washington, D.C.

USEPA. 2010. EPA's Methodology to Calculate Baseline Estimates of Impervious Area (IA) and Directly Connected Impervious Area (DCIA) for Massachusetts Communities.

Voorhees, Mark, USEPA. 2015. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

Voorhees, Mark, USEPA. 2016a. “FW: EPA Region 1 SW BMP performance equations.” Message to Chad Yaindl, Geosyntec Consultants. January 25, 2016. E-mail.

Voorhees, Mark, USEPA. 2016b. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

 

Water Quality Assessment Reports

“Merrimack River Watershed 2004 Water Quality Assessment Report”

 

 

TMDL

No TMDL Found

 

 

 

 

 

 

 

 

APPENDICES

Appendix A – Pollutant Load Export Rates (PLERs)

 

Land Use & Cover1	PLERs (lb./acre/year)
	(TP)	(TSS)	(TN)
AGRICULTURE, HSG A	0.45	7.14	2.59
AGRICULTURE, HSG B	0.45	29.4	2.59
AGRICULTURE, HSG C	0.45	59.8	2.59
AGRICULTURE, HSG D	0.45	91.0	2.59
AGRICULTURE, IMPERVIOUS	1.52	650	11.3
COMMERCIAL, HSG A	0.03	7.14	0.27
COMMERCIAL, HSG B	0.12	29.4	1.16
COMMERCIAL, HSG C	0.21	59.8	2.41
COMMERCIAL, HSG D	0.37	91.0	3.66
COMMERCIAL, IMPERVIOUS	1.78	377	15.1
FOREST, HSG A	0.12	7.14	0.54
FOREST, HSG B	0.12	29.4	0.54
FOREST, HSG C	0.12	59.8	0.54
FOREST, HSG D	0.12	91.0	0.54
FOREST, HSG IMPERVIOUS	1.52	650	11.3
HIGH DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
HIGH DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
HIGH DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
HIGH DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
HIGH DENSITY RESIDENTIAL, IMPERVIOUS	2.32	439	14.1
HIGHWAY, HSG A	0.03	7.14	0.27
HIGHWAY, HSG B	0.12	29.4	1.16
HIGHWAY, HSG C	0.21	59.8	2.41
HIGHWAY, HSG D	0.37	91.0	3.66
HIGHWAY, IMPERVIOUS	1.34	1,480	10.2
INDUSTRIAL, HSG A	0.03	7.14	0.27
INDUSTRIAL, HSG B	0.12	29.4	1.16
INDUSTRIAL, HSG C	0.21	59.8	2.41
INDUSTRIAL, HSG D	0.37	91.0	3.66
INDUSTRIAL, IMPERVIOUS	1.78	377	15.1
LOW DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
LOW DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
LOW DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
LOW DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
LOW DENSITY RESIDENTIAL, IMPERVIOUS	1.52	439	14.1
MEDIUM DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
MEDIUM DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
MEDIUM DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
MEDIUM DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
MEDIUM DENSITY RESIDENTIAL, IMPERVIOUS	1.96	439	14.1
OPEN LAND, HSG A	0.12	7.14	0.27
OPEN LAND, HSG B	0.12	29.4	1.16
OPEN LAND, HSG C	0.12	59.8	2.41
OPEN LAND, HSG D	0.12	91.0	3.66
OPEN LAND, IMPERVIOUS	1.52	650	11.3
1HSG = Hydrologic Soil Group

 

Note: PLER is pollutant load export rate; lb./acre/year is pounds per acre per year; TP is total phosphorus; TSS is total suspended solids; and TN is total nitrogen.

 

 

 

Appendix B – Conceptual Design Sheets

 

[1] https://www.epa.gov/nps/handbook-developing-watershed-plans-restore-and-protect-our-waters

[2] Watersheds are defined by the WBP-tool by using MassGIS drainage sub-basins.

[3]Sources: MassGIS 1999, MassGIS 2001, USGS 2016

[4] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[5] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[6] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[7] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[8] Sources: MassGIS (2015a), MassGIS (2015b), MassGIS (2017a), MassGIS (2017b), MassGIS (2020), MA Department of Revenue Division of Local Services (2016), MassGIS (2005), ArcGIS (2020), MassGIS (2009b), MassGIS (2012), ArcGIS (2020b).

[9] Note: Massachusetts law limits phosphorus in lawn fertilizer.

[10] See Element I for additional monitoring plan information.

[11] The planning level cost estimates, pollutant load reduction estimates, and estimates of the BMP footprint were based off information obtained in the following sources and were also adjusted to 2016 values using the Consumer Price Index (United States Bureau of Labor Statistics 2016): Geosyntec Consultants, Inc. (2014, 2015), King and Hagen (2011), Leisenring, et al. (2014), MassDEP (2016a, 2016b), University of Massachusetts, Amherst (2004), Vorhees (2015, 2016a, 2016b).

[12] O&M costs are based on professional judgement, may vary significantly, and are subject to change.

[13] Estimated costs are AACE Level 4 conceptual level costs and may vary significantly.

[14] Funding needed value does not include annual operation & maintenance costs.

[15]Grants & Financial Assistance: Watersheds & Water Quality | Mass.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

Date: Jan 20, 2021 at 7:00 PM

Location: Zoom Meeting  -  https://us02web.zoom.us/j/89524981665?pwd =MjlQbW4zYlBaemhXRXVVQjREbHlaZz09

Meeting ID: 895 2498 1665
Passcode: 320894

       +1 929 205 6099 US (New York)

 

7:00 Call to order

7:00 Review of Geosynthec Report and discussion of path forward

 

8:00 Meeting minutes – Review, any updates and vote to the approval of previous minutes

 

8:05 Financial Summary

 

8:15 Duck Pond

 

8:25 Lost Lake / Knops Pond

- Treatment funding

 

8:35 Baddacook Pond

         

8:45 Whitney Pond

 

7:55 Adjourn

 

* Vote may be taken

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.

 

If there was previous agenda for this meeting it is below

 

Date: Jan 20, 2021 at 7:00 PM

Location: Zoom Meeting  -  https://us02web.zoom.us/j/89524981665?pwd =MjlQbW4zYlBaemhXRXVVQjREbHlaZz09

Meeting ID: 895 2498 1665
Passcode: 320894

       +1 929 205 6099 US (New York)

 

7:00 Call to order

7:00 Review of Geosynthec Report and discussion of path forward

 

8:00 Meeting minutes – Review, any updates and vote to the approval of previous minutes

 

8:05 Financial Summary

 

8:15 Duck Pond

 

8:25 Lost Lake / Knops Pond

- Treatment funding

 

8:35 Baddacook Pond

         

8:45 Whitney Pond

 

7:55 Adjourn

 

* Vote may be taken

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.

If there was previous agenda for this meeting it is below

The following agenda was added or modified on 2022-01-13 11:33:25 by npierce@grotonma.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Town of Groton, MA

in coordination with

Groton Lakes Association

and the

Great Pond Advisory Committee

 

Cover Photo: Lost Lake Boat Ramp Photo Credit: Geosyntec Consultants, Inc.

 

Acknowledgements

The purpose of a Massachusetts Watershed-Based Plan (WBP) is to organize information about Massachusetts' watersheds and present the information in a format that will enhance the development and implementation of projects to restore water quality and beneficial uses in the Commonwealth. The Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was developed by Geosyntec under the direction of Alex Woodle with funding, input, and collaboration from Groton Lakes Association (GLA) and Great Ponds Advisory Committee (GPAC). This WBP was developed using funds from the Community Preservation Act (CPA) and using the Massachusetts Department of Environmental Protection’s (MassDEP’s) Watershed-Based Planning Tool (WBP Tool).

GLA has a goal of preserving and improving the lakes in eastern Groton, including Lost Lake/ Knops Pond. GLA conducts a variety of volunteer events and has been involved with removal of invasive plants and weeds in the lake.

As a nine-member committee in the Town of Groton, GPAC members work on weed management in the lake and make recommendations to the Select Board. Like the GLA, they deal with issues relating to lake management, including health, safety, water quality, and environmental protection.

The following individuals and organizations have contributed invaluable assistance and support for this project:

Core Stakeholders

Alexander Woodle, member of GPAC and GLA

GPAC

GLA

Grotonwood Camp

Gibbet Hill/Weber Restaurant Group

Groton Country Club

Tom Delaney – Director of Public Works (Groton)

 

Project Team

Alexander Woodle, GPAC, GLA

Adam Questad, PE, Geosyntec Consultants, Inc.

Renee Bourdeau, PE, Geosyntec Consultants, Inc.

Julia Keay, PE, Geosyntec Consultants, Inc.

Emma Williamson, EIT, Geosyntec Consultants, Inc.

 

 

Table of Contents

 

Acknowledgements. i

List of Tables. iv

List of Figures. v

Acronyms and Abbreviations. vi

Watershed-Based Plan Background. 1

Incorporating USEPA’s Nine Elements. 1

1.0         Introduction. 3

1.1 Data Sources. 3

1.2 Goal Statement 3

1.3 Plan Development Process. 4

2.0         Characteristics of Lost Lake and Knops Pond. 4

2.1 Land Use. 7

2.2 Impervious Cover 9

3.0         Assessment of Water Quality. 11

3.1 Water Quality Impairments. 11

3.2 Water Quality Goals. 12

3.3 TMDL Pollutant Load Criteria. 14

4.0         Water Quality Summary (Element A) 14

4.1 Additional Water Quality Information. 14

5.0         Water Quality Goals for Lost Lake and Knops Pond (Element B) 35

5.1 Estimated Pollutant Loads. 35

5.2 Water Quality Goals. 37

6.0         Management Actions to Control Phosphorus (Elements C, D, and E) 39

6.1 BMP Hotspot Map. 41

6.2 Field Watershed Investigation. 45

6.3 Existing Management Measures. 48

6.4 Watershed-Wide BMPs. 48

6.5 Site-Specific BMPs. 51

6.6 Non-Structural BMPs and Watershed Outreach (Category 5) 53

7.0         Schedule and Milestones (Elements F and G) 54

8.0         Success Indicators and Evaluation (Element H) 56

9.0 Monitoring Plan (Element I) 57

10.0      Funding for Future Watershed Planning Phases and Implementation. 60

10.1 Cost Estimate and Pollutant Load Reduction Estimates. 60

10.2 Funding for Proposed Management Measures. 61

11.0      Conclusions. 63

12.0      References. 64

Appendix A – Pollutant Load Export Rates (PLERs) 68

Appendix B – Conceptual Design Sheets. 70

 

 

 

 

List of Tables

Table 1: USEPA’s Nine Elements of Watershed Planning

Table 2-1: General Watershed Information

Table 2-2: Watershed Land Uses

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Table 3-3: Surface Water Quality Classification by Assessment Unit

Table 3-4: Water Quality Goals

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion

Table 4-2: Dry Weather Water Quality Parameters

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites

Table 4-5: Groundwater Nutrient Analysis

Table 4-6: Water Quality Data

Table 4-7: Tributary Water Quality Data

Table 4-8: Well Water Quality Data

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants

Table 5-2: Pollutant Load Reductions Needed

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis

Table 6-2: Slope Stabilization Cost Estimates

Table 6-3: Non-Structural BMPs

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs

Table 10-2: Proposed Structural BMP Priority Matrix

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan

 

 

List of Figures

Figure 2-1: Watershed Boundary Map

Figure 2-2: Watershed Land Use Map

Figure 2-3: Watershed Impervious Surface Map

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations

Figure 4-2: Erosion and Point Source Sampling Locations

Figure 4-3: Groundwater Seepage Sampling Locations

Figure 4-4: Sampling Locations

Figure 4-5: Pore Water Nitrate Concentrations

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations

Figure 4-7: Deep Hole Phosphorus Levels

Figure 4-8: Deep Hole Dissolved Oxygen Levels

Figure 4-9: Deep Hole Chlorophyll-a Levels

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation

Figure 4-11: Tributary Phosphorus Concentrations

Figure 4-12: Sampling Stations

Figure 4-13: Photos from GLA Presentation

Figure 6-1: Proposed BMP Locations

Figure 6-2: BMP Hotspot Map

Figure 6-3: Erosion Off Paved Roads

Figure 6-4: Erosion on Unpaved Roads

Figure 6-5: Typical Ditch Detail

Figure 6-6: Catch Basin Filtration Inlet System

Figure 9-1: Proposed Monitoring Locations

 

 

 

Acronyms and Abbreviations

AACE	Association for the Advancement of Cost Engineering
BMP	Best Management Practice
°C	Celsius
CEI	Comprehensive Environmental, Inc.
cells/mL	cells per milliliter
CPI	Consumer Price Index
DCIA	Directly Connected Impervious Areas
DO	Dissolved Oxygen
USEPA	United States Environmental Protection Agency
ET	Evapotranspiration
FC	Fecal Coliform
FS	Fecal Streptococci
GIS	Geographic Information System
GLA	Groton Lakes Association
GPAC	Great Ponds Advisory Committee
lbs.	pounds
lbs./acre/yr.	pounds per acre per year
lbs./yr.	pounds per year
MassDEP	Massachusetts Department of Environmental Protection
mg/L	milligrams per liter
µg/L	microgram per liter
ml	milliliter
NPS	Nonpoint Source
NRCS	National Resource Conservation Service
O&M	Operation and Maintenance
P	precipitation
PLER	Pollutant Load Export Rate
ppb	parts per billion
QAPP	Quality Assurance Project Plan
QA/QC	Quality Assurance / Quality Control
R	Runoff Depth
TIA	Total Impervious Area
TKN	Total Kjeldahl Nitrogen
TMDL	Total Maximum Daily Load
TN	Total Nitrogen
tons/year	tons per year
TP	Total Phosphorus
TSS	Total Suspended Solids
USDA	U.S. Department of Agriculture
USGS	U.S. Geological Survey
WBP	Watershed-Based Plan

 

Watershed-Based Plan Background

A Massachusetts Watershed-Based Plan (WBP) organizes information about a Massachusetts watershed and presents the information in a format that supports the development and implementation of projects to restore water quality and beneficial uses. A Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was prepared for the Lost Lake/Knops Pond watershed in the town of Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). There are two main tributaries: Martins Pond Brook and an Unnamed Tributary.

Incorporating USEPA’s Nine Elements

The Lost Lake/Knops Pond Watershed-Based Plan includes nine criteria[1] for restoring waters impaired by nonpoint source (NPS) pollution. In this plan, the criteria will be called Elements A through I. These guidelines set forth by USEPA, highlight important steps in protecting water quality for waterbodies impacted by human activities and include specific recommendations for guiding future development, as well as strategies for reducing the cumulative impacts of NPS pollution on water quality. The nine criteria are as follows:

1. Identify causes and sources of pollution: The plan must identify the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated herein (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in Element B immediately below. Sources that need to be controlled should be identified at the significant subcategory level with estimates of the extent to which they are present in the watershed (e.g., X numbers of dairy cattle feedlots needing upgrading, including a rough estimate of the number of cattle per facility; Y acres of row crops needing improved nutrient management or sediment control; or Z linear miles of eroded stream bank needing remediation).
2. Estimate pollutant loading into the watershed and the expected load reductions: The plan must estimate the load reductions expected for the management measures described under Element C below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time). Estimates should be provided at the same level as in Element A above (e.g., the total load reduction expected for dairy cattle feedlots; row crops; or eroded stream banks).
3. Describe management measures that will achieve load reductions and targeted critical areas: The plan must describe the NPS management measures that will be implemented to achieve the load reductions estimated under Element B above (as well as to achieve other watershed goals identified in this watershed-based plan), and an identification, using a map or a description, of the critical areas in which those measures will be needed to implement this plan.
4. Estimate amounts of technical and financial assistance and the relevant authorities needed to implement the plan: The plan must contain estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, for implementation. As sources of funding, states should consider Section 319 programs, State Revolving Funds, USDA’s Environmental Quality Incentives Program and Conservation Reserve Program, and other relevant federal, state, local, and private funds.
5. Develop an information/education component: An information/education component will enhance public understanding of the project and encourage early and continued public participation in selecting, designing, and implementing the NPS management measures.
6. Develop a project schedule: A schedule for implementing the NPS management measures identified in this plan will be established.
7. Describe the interim, measurable milestones: The plan will set forth interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented.
8. Identify indicators to measure progress: The plan will include set of criteria to determine whether loading reductions are being achieved over time and whether substantial progress is being made towards attaining water quality standards. In the case that reductions are not achieved, or progress is not made, criteria will also be established for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised.
9. Develop a monitoring component: A monitoring component will evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under Element H immediately above.

The primary goal of this WBP is to assess the Lost Lake/Knops Pond watershed and provide a plan for implementing actions that will result in measurable improvements in water quality. To achieve this goal, this WBP was developed to include the following nine elements in conformance with USEPA guidance discussed above.

Table 1: USEPA’s Nine Elements of Watershed Planning

Element	Plan Section	Element Description
A	4.0	Identify causes and sources of pollution
B	5.0	Estimate pollution load reductions needed for restoration
C	6.0	Identify actions needed to reduce pollution
D	6.0	Estimate costs and authority to implement restoration actions
E	6.0	Implement outreach and education to support restoration
F	7.0	Restoration schedule
G	7.0	Milestones—interim measures to show implementation progress
H	8.0	Success indicators and evaluation—criteria to show restoration success
I	9.0	Monitoring plan

 

1.0       Introduction

The Lost Lake/Knops Pond WBP describes water quality conditions, watershed characteristics, and sources of phosphorus loading to Lost Lake/Knops Pond. The WBP also establishes water quality goals, proposes best management practices (BMPs) for reducing nutrient loading, and estimates associated costs.

The overall goals of the Lost Lakes/Knops Pond WBP are as follows:

• Identify and quantify sources of nutrient loading to the lake
• Establish water quality goal(s) for the watershed
• Propose BMPs to reduce nutrient loading

The adaptive management approach described in the plan allows project partners flexibility in implementing BMPs. Additionally, the plan recognizes that improvements in water quality cannot be achieved with a single BMP and that results are typically not immediate. The proposed water quality monitoring will help guide the approach and quantify the impacts of implemented BMPs.

1.1 Data Sources

This WBP was developed using data sources provided by the Massachusetts Department of Environmental Protection (MassDEP). Additional data sources were reviewed and are described in subsequent sections of this WBP and listed below:

• Lost Lake Watershed Management Plan (ESS Group Inc. 2017)
• Aquatic Vegetation Program 2017 Annual Report, Solitude Lake Management (Solitude 2017)
• Lost Lake Water Quality Investigation Report, Comprehensive Environmental, Inc. (CEI 2013)
• A Diagnostic/Feasibility Study for the Management of Lost Lake/ Knopps [sic] Pond (Baystate Environmental Engineers 1989)
• Lost Lake/Knops Pond Resources Management Plan (GLA 2012)
• Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

1.2 Goal Statement

The long-term goal of this WBP is to reduce total phosphorus (TP) and other nutrient and sediment loadings to Lost Lake/Knops Pond. These pollutant load reductions may result in improvements to water quality conditions in Lost Lake/Knops Pond, as well as reducing the occurrence of eutrophication.

This goal will be accomplished primarily through installation of BMPs to capture runoff while reducing erosion and related nutrient and sediment loading to Lost Lake/Knops Pond from areas near the lake and from its two main tributaries. BMPs are proposed at multiple locations throughout the watershed.

1.3 Plan Development Process

This WBP was developed through collaboration during project management team meetings and conference calls primarily between Geosyntec, Alexander Woodle, and other members of GPAC and GLA.

An iterative process was used to develop the WBP, as outlined below:

• The Project Team (from Geosyntec Consultants, Inc.) first collected and reviewed existing data from the GLA and the GPAC and other available sources.
• A meeting was held on August 12, 2021 to solicit input and information about the Lost Lake/Knops Pond watershed and to identify possible sources of pollution, existing BMP projects, potential BMP opportunity locations, water quality goals, and public outreach activities.
• The Project Team then visited the site on August 30, 2021 to gather data on problem areas and potential BMP opportunity sites.
• A meeting was held on October 21, 2021 to update stakeholders regarding the site visit and to solicit feedback on proposed strategies to improve the water quality within the watershed.
• A WBP was drafted and reviewed by GPAC and GLA.
• The WBP was finalized based on GPAC and GLA input.

2.0       Characteristics of Lost Lake and Knops Pond

This WBP was prepared for the Lost Lake/Knops Pond watershed, in Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). The watershed is mostly forested, with low density residential areas near the lake and agricultural land use in the northwest portion of the watershed. Historically, the land use in the watershed was predominantly agricultural, especially in the northwestern part of the watershed near Martins Brook Pond. Now, activities in the watershed are mostly recreational (e.g., boating, swimming, and fishing on the lake) and agricultural (small farms in the northwest part of the watershed).

Lost Lake and Knops Pond, collectively referred to as Lost Lake/Knops Pond is one water body with two parts. The Lost Lake is the northern section and Knops Pond is the southern section. They join at the area between Ridgewood Road and Radio Road.

There are two main inlets to the lake: Martins Brook that discharges from Martins Brook Pond into the north of the lake and a shorter unnamed tributary that discharges into the west side of the lake. The lake discharges into Whitney Pond to the northeast.

Table 2-1 presents the general watershed information for the Lost Lake/Knops Pond watershed[2] and Figure 2-1 includes a map of the watershed boundary (Mass Geographic Information Systems (GIS) 2001).

Table 2-1: General Watershed Information

Watershed Name (Assessment Unit ID):	Lost Lake/Knops Pond (MA84084)
Major Basin:	Merrimack
Watershed Area:	3,099.3 acres
Water Body Size:	186 acres

Figure 2-1: Watershed Boundary Map[3]

Ctrl + Click on the map to view a full-sized image in your web browser

 

2.1 Land Use

Land use in the Lost Lake/Knops Pond watershed is mostly forested and accounts for approximately 65 percent (%) of the watershed; approximately 12% of the watershed is low density residential; approximately 9% of the watershed is water; approximately 7% of the watershed is agriculture; approximately 4% of the watershed is open land; approximately 2% of the watershed is high density residential; approximately 1% of the watershed is medium density residential; less than 1% of the watershed is commercial or industrial; and 0% of the watershed is designated as highway (Table 2-2; Figure 2-2). Roadways are included in the residential percentages.

A large portion of the residential area is located around Lost Lake/Knops Pond. The area is mostly low density residential, with more developed areas to the northeast of the lake, off Lost Lake Drive. There is a large, forested area north of the lake and agricultural areas (small farms, including cattle and horse farms) in the northwest portion of the watershed.

Table 2-2: Watershed Land Uses

Land Use	Area (acres)	Percent of Watershed
Forest	2,010	64.9
Low Density Residential	383	12.3
Water	285	9.2
Agriculture	204	6.6
Open Land	113	3.6
High Density Residential	51	1.7
Medium Density Residential	31	1.0
Commercial	22	0.7
Highway	0	0.0
Industrial	0	0.0

 

Figure 2-2: Watershed Land Use Map[4]

Ctrl + Click on the map to view a full-sized image in your web browser

2.2 Impervious Cover

There is a strong link between impervious land cover and stream water quality. Impervious cover includes surfaces that prevent the infiltration of water into the ground, such as paved roads and parking lots, roofs, and basketball courts. Most of the impervious cover in the watershed is associated with roads (Figure 2-3).

Impervious areas that are directly connected (DCIA) to receiving waters (via storm sewers, gutters, or other impervious drainage pathways) produce higher runoff volumes and transport stormwater pollutants with greater efficiency than disconnected impervious areas, which are surrounded by vegetated, pervious land. Runoff from disconnected impervious areas is reduced as stormwater flows across adjacent pervious surfaces and infiltrates.

Estimated DCIA for the watershed was calculated using Sutherland equations. USEPA provides guidance (USEPA 2010) on the use of these equations to predict relative levels of connection and disconnection based on the type of stormwater infrastructure within the total impervious area (TIA) of a watershed. Within each subwatershed, the total area of each land use was summed and used to calculate the percent TIA. The estimated TIA and DCIA for the Lost Lake/Knops Pond watershed is 5.7% and 3.6%, respectively.

Although the estimated TIA in the Lost Lake/Knops Pond watershed falls in the 0% and 10% range that typically denotes high quality, this estimation does not account for erosion on unpaved roads or on the slopes of paved roads, that has led to pollution within the lake. The relationship between TIA and water quality can generally be categorized as shown in Table 2-3 (Schueler et al. 2009):

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality (Schueler et al. 2009)

Percent Watershed Impervious Cover	Stream Water Quality
0–10	Typically, high quality, and typified by stable channels, excellent habitat structure, good to excellent water quality, and diverse communities of fish and aquatic insects.
11–25	Clear signs of degradation. Elevated storm flows begin to alter stream geometry, with evident erosion and channel widening. Stream banks become unstable, and physical stream habitat is degraded. Stream water quality shifts into the fair/good category during storms and dry weather. Stream biodiversity declines to fair levels, with most sensitive fish and aquatic insects disappearing from the stream.
26–60	Typically, no longer supportive of a diverse stream community. The stream channel becomes highly unstable, and many stream reaches experience severe widening, downcutting, and streambank erosion. Pool and riffle structure needed to sustain fish is diminished or eliminated and the substrate no longer provides habitat for aquatic insects or spawning areas for fish. Biological quality is typically poor, dominated by pollution tolerant insects and fish. Water quality is consistently fair to poor, and water recreation is often no longer possible due to high bacteria levels.
>60	These streams are typical of “urban drainage,” with most ecological functions greatly impaired or absent, and the stream channel primarily functioning as a conveyance for stormwater flows.

 

Figure 2-3: Watershed Impervious Surface Map[5]

Ctrl + Click on the map to view a full-sized image in your web browser

3.0       Assessment of Water Quality

The goals of this WBP are founded upon the State’s water quality goals and criteria, which specify the indicators by which water quality improvements are measured. This section is an overview of the standards and criteria that apply to Lost Lake/Knops Pond.

3.1 Water Quality Impairments

Known water quality impairments are documented in MassDEP’s 2016 Massachusetts Integrated List of Waters (MassDEP 2019). The impairment categories from this document are set forth in Table 3-1, and water quality impairments are listed in Table 3-2.

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Integrated List Category	Description
1	Unimpaired and not threatened for all designated uses
2	Unimpaired for some uses and not assessed for others
3	Insufficient information to make assessments for any uses
4	Impaired or threatened for one or more uses, but not requiring calculation of a Total Maximum Daily Load (TMDL), including: 4A: TMDL is completed 4B: Impairment controlled by alternative pollution control requirements 4C: Impairment not caused by a pollutant—TMDL not required
5	Impaired or threatened for one or more uses and requiring preparation of a TMDL

 

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Assessment Unit ID	Waterbody	Integrated List Category	Designated Use	Impairment Cause	Impairment Source
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Atmospheric Deposition—Toxics
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Source Unknown
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Eurasian Water Milfoil, Myriophyllum spicatum[6]	Introduction of Nonnative Organisms (Accidental or Intentional)
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Nonnative Aquatic Plants[7]	Introduction of Nonnative Organisms (Accidental or Intentional)

 

3.2 Water Quality Goals

Water quality goals may be established for many purposes, including the following:

1. Forwater bodies with known impairments, aTotal Maximum Daily Load (TMDL) is established by MassDEP and USEPA as the maximum amount of the target pollutant that the waterbody can receive and still safely meet water quality standards. If the waterbody has a TMDL for total phosphorus (TP), total nitrogen (TN), or total suspended solids (TSS), that information is provided below and included as a water quality goal.
2. Forwater bodies without a TMDL for TP, a default water quality goal for TP is based on target concentrations established in theQuality Criteria for Water (USEPA 1986; also known as the “Gold Book”). The Gold Book states that TP should not exceed 50 micrograms per liter (µg/L) in any stream at the point where it enters any lake or reservoir, nor 25 µg/L within a lake or reservoir. For the purposes of developing WBPs, MassDEP has adopted a TP target of 50 µg/L for all streams at their downstream discharge point, regardless of which type of water body the stream discharges to.
3. Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013) prescribe the minimum water quality criteria required to sustain a waterbody’s designated uses. Lost Lake/Knops Pond is a Class B waterbody. The water quality goal for fecal coliform bacteria is based on the Massachusetts Surface Water Quality Standards.

Table 3-3: Surface Water Quality Classification by Assessment Unit

Assessment Unit ID	Waterbody	Class
MA84084	Lost Lake/Knops Pond	B

 

1. Other water quality goals set by the community(e.g., protection of high-quality waters, in-lake phosphorus concentration goal to reduce recurrence of cyanobacteria blooms).

Table 3-4 shows the pollutant and associated water quality goals. For TP, there is no Nonnative Aquatic Plants TMDL for Lost Lake/Knops Pond (although there is a Mercury in Fish Tissue TMDL); therefore, we are using standards from the Gold Book as described in part b above.

Table 3-4: Water Quality Goals

Pollutant

Goal

Source

Total Phosphorus (TP)	Total phosphorus should not exceed: 50 µg/L in any stream 25 µg/L within any lake or reservoir	Quality Criteria for Water (USEPA 1986)
Bacteria	Class B Standards • Public Bathing Beaches: For E. coli, geometric mean of five most recent samples shall not exceed 126 colonies/100 ml and no single sample during the bathing season shall exceed 235 colonies/100 ml. For enterococci, geometric mean of five most recent samples shall not exceed 33 colonies/100 ml and no single sample during bathing season shall exceed 61 colonies/100 ml. • Other Waters and Nonbathing Season at Bathing Beaches: For E. coli, geometric mean of samples from most recent six months shall not exceed 126 colonies/100 ml (typically based on min. 5 samples) and no single sample shall exceed 235 colonies/100 ml. For enterococci, geometric mean of samples from most recent 6 months shall not exceed 33 colonies/100 ml, and no single sample shall exceed 61 colonies/100 ml.	Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013)

Note: There may be more than one water quality goal for bacteria due to different Massachusetts Surface Water Quality Standards Classes for different Assessment Units within the watershed.

The section below summarizes the findings from the Water Quality Assessment Reports that relate to water quality and impairments. Select excerpts from these documents relating to the water quality in the watershed are included below. (Note that relevant information is included directly from these documents for informational purposes and has not been modified.)

Merrimack River Watershed 2004 Water Quality Assessment Report (MA84084 - Lost Lake/Knops Pond)

Four non-native aquatic plant species (Trapa natans, Myriophyllum spicatum, Cabomba caroliniana, Potamogeton crispus) have been reported in Lost Lake/Knops Pond. The Aquatic Life Use is assessed as impaired based on the presence of non-native aquatic plants. Cause(s) of Impairment: Non-Native Aquatic Plants, Eurasian Water Milfoil (Myriophyllum spicatum) Source(s) of Impairment: Introduction of Non-Native Organisms MassDEP DWM biologists collected fish from the pond in May 2004 and composite samples of edible fillets were analyzed for As, Cd, Hg, Pb, Se, PCBs and organochlorine pesticides. MA DPH has issued a fish consumption advisory due to mercury contamination for Lost Lake/Knops Pond. Children younger than 12 years of age, pregnant women, women of childbearing age who may become pregnant, and nursing mothers should not eat any Largemouth Bass fish from this water body. The public should limit consumption of Largemouth Bass fish to two meals per month. Cause(s) of Impairment: Mercury in Fish Tissue Source(s) of Impairment: Atmospheric Deposition - Toxics, Source Unknown Insufficient data were available to assess the Primary Contact Recreational Use. Insufficient data were available to assess the Secondary Contact Recreational Use. Insufficient data were available to assess the Aesthetics Use. Report Recommendations: Conduct monitoring to confirm the presence of non-native aquatic plants.

 

3.3 TMDL Pollutant Load Criteria

Due to the Mercury in Fish Tissue impairment, Lost Lake/Knops Pond is subject to a Regional Mercury TMDL, linked below.

• Northeast Regional Mercury Total Maximum Daily Load

The Lost Lake/Knops Pond watershed does not have a TMDL for non-native plants. MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for the Eurasian Water Milfoil (Myriophyllum spicatum) and Non-Native Aquatic Plants impairments as the impairments are nonpollutants (MassDEP 2019).

4.0       Water Quality Summary (Element A)

In addition to the water quality data discussed in Section 3, above, multiple studies have been conducted for Lost Lake/Knops Pond. Additionally, multiple methods to control invasive plant growth have been implemented, including those described in the 2012 Lost Lake/Knops Pond Resources Management Plan (GLA 2012) and the 2017 Aquatic Vegetation Management Program Annual Report for Lost Lake/Knops Pond (Solitude 2017). A detailed timeline of invasive aquatic plant control methods used is included in Section 6.  

4.1 Additional Water Quality Information

Additional water quality data and information collected from the Knops Pond/Lost Lake watershed from 1988 through 2017 is described below (ESS Group 2017, CEI, Inc. 2013, Baystate Environmental Engineers 1989, GLA 2014).

4.1.1 Lost Lake Watershed Management Plan (ESS Group, Inc. 2017)

This report describes pollutant and nutrient levels from natural and manmade sources in the Lost Lake/Knops Pond watershed. Results and conclusions from the report are summarized below:

• Sampling Locations. The sampling locations for TSS and point sources, other water quality parameters, and sediment are shown in Figure 4-1. The sampling locations for erosion (stormwater runoff) and point sources are shown in Figure 4-2. The groundwater seepage sampling locations are shown in Figure 4-3.
• Sampling Dates. Sampling was conducted on September 9, October 6, and November 16, 2016.
• Sediment Loading. Six locations were sampled for sediment loading (inlets, outlet, and three sites experiencing erosion), and the results are shown in Table 4-1. Parameters sampled included TSS, pH, specific conductance, salinity, temperature, dissolved oxygen (DO), and turbidity. The report found relatively high TSS levels at the locations experiencing erosion (170, 47, and 100 mg/L at TP-2, TP-3, and TP-4, respectively) compared to the low levels at the outlet (<5.0 milligrams per liter [mg/L]). These findings indicate that sediment settles in the lake and does not exit at the outlet. Additionally, the report states the low TSS values observed at the inlets to the lake (6 and <5.0 mg/L respectively for Inlet 1 and Inlet 2) indicated the sediment settles out before entering the lake.
• Dry Weather Sampling. Seven locations (inlets, outlet, and surface and bottom of both sides of Lost Lake/Knops Pond) were sampled for TP, dissolved phosphorus, nitrite-N, nitrate-N, total Kjeldahl nitrogen (TKN), total nitrogen, and TSS during dry weather. The results of this effort are shown in Table 4-2. The report indicated relatively high concentrations of phosphorus at the inlets (compared to the surface and bottom of Lost Lake/Knops Pond), suggesting large phosphorus sources from within the watershed. The report also stated that low DO concentrations indicated the presence of increased organics, decomposition, and algal growth and subsequent decay that may have been caused by excessive nutrients. The low DO concentrations can also create conditions that are favorable for release of sediment-bound phosphorus in the lake sediment, depending on how the phosphorus is bound.
• Water Profiles at Deepest Locations. Water profiles were collected at the deepest locations in Lost Lake/Knops Pond (Table 4-3). The report stated that water quality profiles indicate that water below 1.5 meters was not capable of supporting a healthy fish community in Lost Lake (the northern portions of Lost Lake/Knops Pond); however, the DO concentrations were suitable in Knops Pond (the southern portions of the waterbody).
• Wet Weather Sampling. The wet weather point source and erosion sampling (stormwater runoff at locations experiencing erosion) results from six stormwater samples are shown in Table 4-4. Water quality data includes TP, dissolved phosphorus, nitrate-N, TKN, flow, TSS, pH, specific conductivity, salinity, temperature, DO, and turbidity results at the inlets, outlet, and four locations experiencing erosion. The report stated that data from the roadway stormwater runoff indicated that shoreline erosion is occurring and that sediments containing nutrients are subsequently entering the lake. The high nutrient load in the sediments is indicated by the high phosphorus concentrations measured at the erosional sites. The report also stated the specific conductivity results indicated the sand and sediment are of more concern to water quality than road de-icing agents, although this may change seasonally.
• Groundwater Sampling. Lastly, groundwater nutrient concentrations and rate of seepage are shown in Table 4-5. The report stated that these results indicated that groundwater is entering the lake and that it may also contain nutrients, including dissolved phosphorus. Depending on the installation process of the seepage meters, the nutrients measured may be from the sediments rather than the groundwater itself.
• The measured TSS and concentrations of phosphorus at the sites experiencing erosion and inlets during sediment loading sampling, dry weather sampling, and wet weather sampling indicate that erosion, and specifically the associated phosphorus load, are a significant source of phosphorus to the lake and are most likely a contributor of nutrient issues and decreased water quality within the lake.

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations (ESS, 2017).

 

Figure 4-2: Erosion and Point Source Sampling Locations (ESS 2017).

Figure 4-3: Groundwater Seepage Sampling Locations (ESS 2017).

 

 

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion (ESS 2017).

Note: mg/L is milligrams per liter; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is part per trillion; C is degrees Celsius; % is percent; mg/L is milligrams per liter; NTU is nephelometric turbidity units.

Table 4-2: Dry Weather Water Quality Parameters (ESS 2017).

Note: SU is standard unit; NTU is nephelometric turbidity units; % is percent, mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius; CFS is cubic feet per second.

 

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond (ESS 2017).

 

Note: m is meters; % is percent; mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius.

 

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites (ESS 2017).

Note: mg/L is milligrams per liter, CFS is cubic feet per second; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is parts per trillion; C is degrees Celsius; % is percent.

Table 4-5: Groundwater Nutrient Analysis (ESS 2017).

Note: mg/L is milligrams per liter; L/m²/day is liters per square meter per day.

4.1.2 Lost Lake Water Quality Investigation Report (CEI 2013)

Limited data was collected from the Deep Hole (deepest point) of Lost Lake in July, August, and September 2013 (1 to 2 samples per location). The Deep Hole sampling results are shown in Figure 4-5 (nitrate concentrations) and Figure 4-6 (nitrate + ammonia concentrations). Pore water sampling locations are shown in Figure 4-4. The pore water sampling results are shown in Figure 4-7 (phosphorus), Figure 4-8 (dissolved oxygen), and Figure 4-9 (chlorophyll-a).

The results for both Deep Hole and pore water sampling locations were compared to 1988/1989 water quality data (measured in the 1989 Diagnostic/Feasibility Study [Baystate Environmental Engineers 1989]). The 2013 report indicated that the data comparison results were inconclusive and that there was no trend in the data. Emerging contaminant data were collected as well; however, the report indicated the data results showed very low levels of several emerging contaminants and limited results associated with wastewater.

The report indicated that phosphorus sampling (shown in Figure 4-10 and Figure 4-11) showed the presence of wastewater, high levels of fertilizer, or other sources due to that fact that many of the phosphorus concentrations exceeded 20 parts per billion (ppb; a rough gauge of good water quality) and even 30 ppb (indicative of watershed issues, especially during a wet summer). However, bacteria were also found, which the report indicated showed the presence of untreated sewage from septic systems or livestock.

Figure 4-4: Sampling Locations (CEI 2013).

Figure 4-5: Pore Water Nitrate Concentrations (CEI 2013).

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations (CEI 2013).

Figure 4-7: Deep Hole Phosphorus Levels (CEI 2013).

Note: ppb is parts per billion.

Figure 4-8: Deep Hole Dissolved Oxygen Levels (CEI 2013).

Note: ppm is parts per million.

Figure 4-9: Deep Hole Chlorophyll-a Levels (CEI 2003).

Note: ppm is parts per million.

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation (CEI 2003).

Figure 4-11: Tributary Phosphorus Levels (CEI 2013).

4.1.3 A Diagnostic / Feasibility Study for the Management of Lost Lake / Knopp’s [sic] Pond (Baystate Environmental Engineers 1989)

This report detailed historic water quality conditions in Lost Lake/Knops Pond and identified the major sources of nutrient loadings in 1989, which may or may not reflect current conditions. The report findings are summarized below:

• Sampling Locations. Figure 4-12 shows water quality sampling locations KP-1 (inlet from unnamed tributary), KP-2 (inlet from Martins Pond Brook), and KP-3 through KP-7 (distributed throughout Lost Lake/ Knops Pond).
• Sampling Results. Water quality sampling results are shown in Table 4-6. The study indicated that results suggested Martin’s Pond Brook was a major source of phosphorus loading and that the phosphorus remineralization under anoxic bottom conditions was not an important source to the lake. The study indicated the orthophosphate data results indicate that the pond is mesotrophic. Ammonia levels were highest during the winter and late fall, which according to the study indicated that organic material was decomposing.
• Tributary Sampling Results. Tributary water quality data was shown in Table 4-7. The results indicated that the Gibbet Hill tributary was an important source of nitrogen and phosphorus and may have led to the high nutrient levels in Martin’s Pond Brook. Additionally, the report indicated that the high density of residences near the lake was a potential source of nutrients.
• Well Water Sampling Results. The well water quality data are shown in Table 4-8. The study indicated that bacteria sampling results showed that septic systems were not responsible for the bacteria counts. It also indicated that bacteria counts were most likely due to wildlife, based on the fecal coliform (FC) to fecal streptococci (FS) ratios.
• Nutrient Loading. Additionally, the study calculated nutrients loads based on sampling data and typical export coefficients for sources in Lost Lake/Knops Pond, including the Unnamed Tributary, Martin’s Pond Brook, “Redwater” (shown in Figure 4-12), groundwater (direct input), atmospheric deposition (direct input), bird inputs (direct input), and internal load (anoxic loading). The results of this nutrient load table (shown in Table 4-9) indicated that approximately 63% of the phosphorus load and 51% of the nitrogen load were from the two inlets.
• Overall, the study indicated most of the phosphorus loading (approximately 63%) was from the two inlets, with most from the inlet to Martins Pond Brook. These results concur with the conclusions from the 2013 and 2017 study, which both identify phosphorus as a nutrient of concern within the watershed, although the 2017 study specifically identifies erosion as a major source.

Figure 4-12: Sampling Stations (Baystate Environmental Engineers 1989).

 

 

Table 4-6: Water Quality Data (Baystate Environmental Engineers 1989).

 

Table 4-7: Tributary Water Quality Data (Baystate Environmental Engineers, 1989).

 

Table 4-8: Well Water Quality Data (Baystate Environmental Engineers 1989).

 

 

 

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond (Baystate Environmental Engineers 1989).

 

 

4.1.4 Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

This presentation by GLA on the topic of erosion and stormwater runoff included photos and locations with moderate to severe erosion due to stormwater runoff. Photos from the presentation are shown in Figure 4-13. The following roads and locations were shown:

·         Alder Road	·         Moose Trail
·         Baby Beach	·         Off Prescott Street
·         Birchwood Avenue	·         Paul Revere Trail and Boat Launch
·         Boathouse Road	·         Point Road
·         Highland Road	·         Radio Road
·         Intersection of Pine and Paul Revere Trails	·         Redskin Trail
·         Island Road and Island Road Bridge	·         Shelters Road
·         Juniper Point	·         Summit Avenue
·         Lost Lake Drive at Outlet	·         Wenuchias Trail
·         Maplewood Avenue	·         Weymisset Road

 

Figure 4-13: Photos from GLA Presentation (GLA 2014).

From left to right: Boathouse Road, Paul Revere Trail off Pine Trail (Lost Lake Boat Launch), and Alder Road.

5.0       Water Quality Goals for Lost Lake and Knops Pond (Element B)

Water quality goals are a critical component of watershed management plans; they are the “yardstick” by which management success is measured. The water quality goals describe the pollutant load reductions that indicate improvement in the lake’s water quality. The establishment of water quality goals for Lost Lake/Knops Pond was guided by an analysis of water quality data, nutrient load modeling using the WBP tool, and with input from GPAC and GLA.  

5.1 Estimated Pollutant Loads

GIS was used for the pollutant loading analysis. The land-use data (MassGIS 2009b) was intersected with impervious cover data (MassGIS 2009a) and USDA Natural Resources Conservation Service (NRCS) soils data (USDA NRCS, MassGIS 2012) to create a combined land use/land cover grid. The grid was used to sum the total area of each unique land use/land cover type.

The amount of DCIA was estimated using the Sutherland equations as described above, and any reduction in impervious area due to disconnection (i.e., the area difference between TIA and DCIA) was assigned to the pervious D soil category for that land use to simulate that some infiltration will likely occur after runoff from disconnected impervious surfaces passes over pervious surfaces.

Pollutant loading for key nonpoint source pollutants in the watershed was estimated by multiplying each land use/cover type area by its pollutant load export rate (PLER). The PLERs are an estimate of the annual total pollutant load exported via stormwater from a given unit area of a particular land cover type. The PLER values for TN, TP, and TSS were obtained from USEPA (Voorhees 2016b; see documentation provided in Appendix A) as follows:

L_n = A_n * P_n

Where L_n = Loading of land use/cover type n in pounds per year (lbs./yr.); A_n = area of land use/cover type n (acres); P_n = pollutant load export rate of land use/cover type n in pounds per acre per year (lbs./acre/yr.).

Table 5-1 presents the estimated land-use based TP, TN, and TSS within the Lost Lake/Knops Pond watershed. The largest contributor of land-use based TP, TN, and TSS load originates from areas designated as forested. TP and TN generated from forested areas is generally a result of natural processes such as decomposition of leaf litter and other organic material; the forested portions of the watershed therefore are unlikely to provide opportunities for nutrient load reductions through BMPs. Low density residential areas (including roads) are the second largest contributors of land-use based TP, TN, and TSS load in the watershed. Residential areas provide excellent opportunities for nutrient load reductions through BMPs, as described in the following sections.

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants.

Land Use Type	Pollutant Loading1
	TP (lbs./yr.)	TN (lbs./yr.)	TSS (tons/yr.)

TOTAL	557	3,659	92.13
Forest	299	1,580	61.99
Low Density Residential	87	871	11.96
Agriculture	99	595	8.19
Open Land	27	269	5.18
High Density Residential	23	158	2.34
Commercial	12	109	1.36
Medium Density Residential	9	72	1.04
Industrial	1	6	0.07
Highway	0	0	0.00
1These estimates do not consider loads from point sources or septic systems. Note: TP is total phosphorus; TN is total Nitrogen; TSS is total suspended solids; and lbs./yr. is pounds per year.

 

It is important to note that pollutant loads presented in Table 5-1 do not consider loads from point sources or septic systems. In the Lost Lake/Knops Pond watershed, septic systems have been identified as a potential source of pollutant loading since they are used throughout the watershed. Septic system sources should be separately evaluated to determine whether septic system upgrades or sanitary sewer system conversion would cost-effectively reduce bacteria and nutrient sources in the watershed.

5.2 Water Quality Goals

Many methodologies can be used to set pollutant load reduction goals for a WBP. Goals can be based on water quality criteria, surface water standards, existing monitoring data, existing TMDL criteria, or other data. As discussed in Element A, water quality goals for this WBP are focused on reducing nutrient (TP and TN) and sediment (TSS) loads to Lost Lake/Knops Pond. The water quality goals, and corresponding required loading reductions are included in Table 5-2.

Water quality goals for primary NPS pollutants are listed in Table 5-2 based on the following:

• TMDL water quality goals are used if a TMDL exists for the water body.
• For all water bodies, including impaired waters with a pathogen TMDL, the water quality goal for bacteria is based on theMassachusetts Surface Water Quality Standards (314 CMR 4.00 2013) that apply to the Water Class of the selected water body.
• If the water body does not have a TMDL for TP, a default target TP concentration is provided which is based on guidance provided in the Gold Book. Because there are no similar default water quality goals for TN and TSS, goals for these pollutants are provided in Table 5-2 only if a TMDL exists or alternate goal(s) have been optionally established by the WBP author.
• According to the Gold Book, total phosphorus should not exceed 50 µg/L in any stream at the point where it enters any lake or reservoir. The water quality loading goal was estimated by multiplying this target maximum phosphorus concentration (50 µg/L) by the estimated annual watershed discharge for the selected water body. To estimate the annual watershed discharge, the mean flow was used, which was estimated based on United States Geological Survey (USGS) “Runoff Depth” estimates for Massachusetts (Cohen and Randall 1998). This document provides statewide estimates of annual Precipitation (P), Evapotranspiration (ET), and Runoff depths ® for the northeastern United States. According to their method, R is defined as all water reaching a discharge point (including surface and groundwater) and is calculated by:

P – ET = R

A mean R was determined for the watershed by calculating the average value of R within the watershed boundary. This method includes the following assumptions/limitations:

1. For lakes and ponds, the estimate of annual TP loading is averaged across the entire watershed. However, a given lake or reservoir may have multiple tributary streams, and each stream may drain land with vastly different characteristics. For example, one tributary may drain a highly developed residential area, while a second tributary may drain primarily forested and undeveloped land. In this case, one tributary may exhibit much higher phosphorus concentrations than the average of all streams in the selected watershed.
2. The estimated existing loading value only accounts for phosphorus due to stormwater runoff. Other sources of phosphorus may be relevant, particularly phosphorus from on-site wastewater treatment (septic systems) close to receiving waters. Phosphorus does not typically travel far within an aquifer, but in watersheds that are primarily unsewered, septic systems and other similar groundwater-related sources may contribute a significant load of phosphorus that is not captured in this analysis. As such, it is important to consider the estimated TP loading as “the expected TP loading from stormwater sources.”
3. If the calculated water quality goal is higher than the existing estimated total load, the water quality goal is automatically set equal to the existing estimated total load.

The WBP tool calculates an estimated TP load of 557 lbs./yr. and a water quality goal of 557 lbs./yr. of TP. This would mean that the required load reduction is 0 lbs./yr. to meet the water quality goal. However, the estimated pollutant load and water quality goal do not account for nutrient load from the observed erosion (the soil may be nutrient-rich due to historical agricultural use), septic systems, waterfowl, atmospheric, and/or internal load. The pollutant load also does not account for current land use (e.g., recent development) as the model uses an older land use dataset (2016). Furthermore, observations of roadway erosion and eutrophication throughout the watershed during the site visit indicate that a reduction in nutrient load is required to improve water quality in Lost Lake/Knops Pond.

Therefore, a load reduction of 10% of the existing estimated total load of TP, TN, and TSS is proposed as the required load reduction. Modifications to the required load reduction would be made based on the results of the water quality monitoring program.  

The following adaptive sequence is recommended to sequentially track and meet these load reduction goals:

1. Establish a short-term reduction goal to reduce land-use-based TP, TN, and TSS by 10%. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons per year (tons/yr.) for TP, TN, and TSS, respectively.
2. Implement a baseline water quality monitoring program in accordance with Element I. Results from the monitoring program should advise if Element C BMPs have been effective at addressing listed water quality impairments or water quality goals. Results can further be used to create, periodically inform, or adjust load reduction goals.
3. Establish a long-term reduction goal to reduce land-use-based TP, TN, and TSS over the next 15 years based on monitoring data.

Table 5-2: Pollutant Load Reductions Needed.

Pollutant	Existing Estimated Total Load	Water Quality Target	Required Load Reduction for short-term goal (10%)
Total Phosphorus	557 lbs./yr.	501 lbs./yr.	56 lbs./yr.
Total Nitrogen	3,659 lbs./yr.	3,293 lbs./yr.	366 lbs./yr.
Total Suspended Solids	92 tons/yr.	83 tons/yr.	9 tons/yr.

Note: lbs./yr. is pounds per year.

The proposed BMPs described in this WBP are expected to reduce TP, TN, and TSS loads to Lost Lake/Knops Pond; however, additional BMP implementation/load reduction may be required to meet the water quality goals.

 

6.0       Management Actions to Control Phosphorus (Elements C, D, and E)

The proposed management measures were determined using an iterative process. First, the hotspot map was reviewed, and potential sites located on Town-owned parcels were selected. Next, the field investigation was conducted to assess whether the selected sites are suitable for BMPs and to determine the BMP that best fit site characteristics (e.g., topography, soil type, area). Areas not initially selected were added to the list of potential sites if the area was determined to be suitable for a BMP during the site investigation. After the site investigation, a desktop review was conducted to determine the siting of the BMPs, and the estimated nutrient load reduction based on drainage area and land use. The proposed BMPs were presented to members of the GLA and GPAC during the stakeholder meeting on October 21, 2021. The final proposed BMPs were selected based on feedback from the stakeholder meeting.

Nutrient load reductions for the proposed BMPs were determined using the WBP tool with drainage areas and land use calculated in GIS. The WBP tool also calculates the estimated BMP footprint. The cost estimates for the site-specific BMPs were determined using the initial baseline provided by the WBP tool and adding 30% for design costs, 10% for permitting costs, 10% for project management costs, and 15% for contingency. A 50% contingency was added to represent the maturity level based on the Association for the Advancement of Cost Engineering (AACE) Level 4 cost estimate.

There are two main types of proposed management measures: (1) watershed-wide BMPs that are recommended for implementation throughout the watershed in addition to the key locations specified in this WBP and (2) site-specific BMPs that are recommended for a specific location in the watershed. The proposed management measures are all structural BMPs, except for catch basin cleaning which is a nonstructural or programmatic BMP. Figure 6-1, below, shows the proposed BMP locations.

 

Figure 6-1: Proposed BMP Locations.

6.1 BMP Hotspot Map

BMPs are management measures, activities, and maintenance procedures that prevent or reduce nonpoint source or point source pollution to achieve water quality goals. Examples of BMPs include rain gardens, vegetated swales, and catch basin maintenance. The following points describe the GIS-based analysis conducted within the watershed to identify high priority parcels for BMP implementation:

• Each parcel within the watershed was evaluated based on ten criteria accounting for the parcel ownership, social value, and implementation feasibility (See Table 6-1 for more detail below).
• Each criterion was then given a score from 0 to 5 to represent the priority for BMP implementation based on a metric corresponding to the criterion. (A score of 0 would represent lowest priority for BMP implementation whereas a score of 5 would represent highest priority for BMP implementation.)
• A multiplier was also assigned to each criterion, which reflected the weighted importance of the criterion. (A criterion with a multiplier of 3 had greater weight on the overall prioritization of the parcel than a criterion with a multiplier of 1.)
• The weighted scores for the criteria were then summed for each parcel to calculate a total BMP priority score.

Table 6-1 presents the criteria, indicator type, metrics, scores, and multipliers for this analysis. Parcels with total scores above 60 are recommended for further investigation for BMP implementation suitability.

Figure 6-2 presents the resulting BMP Hotspot Map for the watershed. The following link includes a Microsoft Excel file with information for parcels with a score above 60: hotspot spreadsheet. These parcels are spread out within the watershed and generally are not directly adjacent to Lost Lake/Knops Pond, except for the forested parcels to the northwest of the lake. Additionally, the lack of suitable parcels adjacent to the watershed suggests that proposed BMPs may need to be implemented either in the roadway right-of-way or on smaller parcels of public land, and/or that multiple BMPs may be needed to significantly improve the water quality in the lake. Because several parcels in the northwest portion of the watershed with known current and historic agricultural activities are on the BMP Hotspot map, if monitoring results indicate that agricultural activities are contributing excessive nutrient load to the watershed, BMPs may be implemented in this area.

This analysis solely evaluated individual parcels for BMP implementation suitability and likelihood for the measures to perform effectively within the parcel’s features. This analysis does not quantify the pollutant loading to these parcels from the parcel’s upstream catchment. When further evaluating a parcel’s BMP implementation suitability and cost-effectiveness of BMP implementation, the existing pollutant loading from the parcel’s upstream catchment and potential pollutant load reduction from BMP implementation should be evaluated.

GIS data used for the BMP Hotspot Map analysis included:

• MassGIS (2015a);
• MassGIS (2015b);
• MassGIS (2017a);
• MassGIS (2017b);
• MassGIS (2020);
• Massachusetts Department of Revenue Division of Local Services (2016);
• MassGIS (2005);
• ArcGIS (2020);
• MassGIS (2009b);
• MassGIS (2012); and
• ArcGIS (2020b).

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis.

 

Figure 6-2: BMP Hotspot Map[8]

Ctrl + Click on the map to view a full-sized image in your web browser

6.2 Field Watershed Investigation

Geosyntec conducted a field investigation in the Lost Lake/Knops Pond watershed on August 30, 2021 to identify and confirm sources of pollution and to identify potential BMPs that can be implemented to reduce the pollutant load to Lost Lake/Knops Pond.

Findings from the site visit are described below:

• Birchwood Avenue/Hazelwood Avenue and the “Inlet 2” north of Birchwood Avenue. At this location, erosion was observed along roads and in residential driveways. Here, the stream is small and slow-moving (approximately 3 feet wide with approximately 1-inch-deep flowing water). An observed catch basin on Birchwood Avenue was partially covered with concrete and filled with sediment.
• Off Prescott Road. Here, a dirt road appeared to have been recently regraded.
• Grotonwood Camp At this location, a large parking lot, untreated stormwater runoff appears to concentrate east of the building and discharge into the woods where there was visible erosion. The opportunity exists to implement a stormwater BMP here; this location also has public education and outreach potential. A French drain is also located in this location, which appears to have been more recently installed and collects roof runoff and discharges into the wooded area.
• Martins Pond Brook crossing (culvert) at Martins Pond Road. At this location, catch basin full of sediment was observed.
• Shattuck Street. Here, Martins Pond Road, a dirt road, appears to be contributing sediment to the downstream paved road, where the sediment is entering the catch basins.
• Scarlet Hill Farm (horse farm). Here, the Project Team walked along a portion of the horse farm from Shattuck Street where it abuts Martins Pond Brook; they did not see any evidence of horses having access to the brook.
• Met with John Smigelski at 150 Mill St (Excalibur Farm). John Smigelski showed the Project Team soil sampling data (2011 and earlier years) from his fields off of Groton School Road, which are not within the watershed. The samples indicated elevated levels of TP in the topsoil. John noted that he does not add phosphorus to his soils since the levels are high.
• Lowell Road. Here, it appears that stormwater runoff from Gibbet Hill Grill (restaurant and grazing land) as well as Lawrence Academy discharges to a stormwater pond south of Lowell Road.
• Martin’s Pond Brook crossing (culvert) at Lowell Road. The brook is very slow moving here, and banks are densely vegetated.
• Lost Lake Drive. Here, Martin’s Pond Brook flows through large wetland area. Catch basins along Lost Lake Drive appear to discharge to the wetland.
• Fire Station on Lost Lake Drive. Catch basin with visible sediment buildup on pavement nearby was observed in the driveway; there is the potential for BMP implementation here, though the Project Team suspects that the drainage area is not very large.
• Tavern Road. Erosion was observed on both sides of road; Martins Pond Brook (“Inlet 1”) discharges into the pond east of Tavern Road.
• Boat House Road. Erosion was observed on both sides of road.
• Observed outlet of watershed (beginning of Cow Pond Brook).
• Boat Launch/Fisherman access off of Pine Trail. Erosion and sedimentation were observed in the parking area, as was evidence of sediment loading from Pine Trail down the steep entrance to the parking area. An opportunity to implement a BMP exists at this location. The wetland and pond adjacent to the parking area was stagnant and showed signs of eutrophication
• Highland Road, Radio Road, Weymisset Road, and Island Road. Numerous areas along road and residential driveways with erosion were observed.

Algal blooms, an indication of eutrophication, were present in the ponds that were visited. Locations include off of Radio Road, Tavern Road, the Lost Lake Boat Launch (Pine Trail), and across from Gibbet Hill Grill. These ponds are located throughout the watershed and demonstrate evidence of excessive nutrients.

Erosion on the sides and slopes of paved roads was present throughout the watershed. Loss of vegetation was also noted. The erosion was especially pronounced and of concern on the “esker” roads, located directly adjacent to Lost Lake/Knops Pond. In many cases, this erosion also presented road stability concerns, as road foundations were eroding into the lake. Figure 6-3, below, shows examples of erosion in the watershed.

Figure 6-3: Erosion off Paved Roads.

From left to right, erosion on Island Road, Radio Road, and Pine Trail.

Gullying and channelization were observed on Radio Road and Pine Trail. On the slope of Radio Road, evidence of stormwater runoff flowing directly into Lost Lake/Knops Pond was observed. Loss of vegetation was observed on Island Road and Pine Tail.

Erosion was present on unpaved roads throughout the watershed. Additionally, evidence of regrading (parked equipment and fresh soil) of dirt roads was found on Off Prescott Street. Figure 6-4 shows examples of erosion on unpaved roads.

Figure 6-4: Erosion on Unpaved Roads.

From left to right, erosion on Off Prescott Street, Birchwood Ave, and Shattuck Street.

Gullying and channelization were observed on Birchwood Avenue and Shattuck Street.

Maintenance needs were also observed at several locations during the field investigation. Sediment was found in catch basins at the intersection of Chester Hill and Martins Pond Road, and there are likely other catch basins in the watershed that require cleaning. Additionally, a catch basin on Maplewood Avenue was partially covered by concrete tiles and filled with sediment.

In addition to the field investigation, the Project Team also contacted large land users in the watershed about their land management practices. The findings from the conversations are summarized below:

• Scarlet Hill Farm. This horse farm has a public trail easement. No significant erosion or other sources of nutrients were observed during the site visit. A stream runs adjacent to the public trail.
• Gibbet Hill/Weber Restaurant Group. There are two main land uses on this property: a leased-out 100% organic vegetable farm and a Black Angus cattle farm with 100 acres for grazing, a 2.5-acre field, ½-acre for lamb pasture and ¼-acre for pigs. There is no irrigation.
• Grotonwood Camp. No fertilizer is used at this property. There is an infiltration system for roof drains and no other constructure stormwater management. This land user expressed interest in future partnering on projects.
• Groton Country Club. A phosphorus free fertilizer is applied to the putting greens once a year and to the fairways in the spring. The fertilizer is not applied on open areas or roughs.
• Lawrence Academy. No information was provided. No significant sources of erosion or other sources of nutrients were identified from the road adjacent to the site.
• Excalibur Farm. Although Excalibur Farm is located outside of the watershed, geological and soil attributes at the farm may be like those within the watershed. Soil tests indicate high phosphorus concentrations, although the source may be from the historical agricultural use, soil properties, or other sources.
• Department of Public Works for Town of Groton. Both salt and sand are used on roads within the watershed and on roads directly adjacent to the watershed. The application varies based on the type of storm: for icy storm, sand is used and for storms with less ice, only salt is used. Calcium chloride is often used with the salt. Typically, the roads adjacent to Lost Lake/Knops Pond are salted/sanded once per storm. The applicator machines are calibrated to use the minimum amount of salt and sand needed to provide deicing.

6.3 Existing Management Measures

Existing management measures in Lost Lake/Knops Pond mostly consist of in-lake treatments to control invasive plants. The following timeline show the progression of herbicide treatments:

• 2002: Herbicidal treatment of the entire lake for the control of milfoil was successful in reducing weed growth (GLA 2012).
  • 2003–2004: Spot treatments were conducted to control regrowth (GLA 2012).
• 2003–2011: Limited work was conducted. A weed harvester operated by GLA was used to control new growth (GLA 2012).
• 2011: GLA hired Aquatic Control Technology to conduct a biological survey and propose management alternatives (GLA 2012).
• 2011–2012: GLA continued use of the weed harvester; weed regrowth, specifically of milfoil and Cabomba was intense due to warmer than typical weather (GLA 2012).
• 2017: Herbicide treatment was applied by Solitude Lake Management and focused on areas of dense milfoil, curlyleaf pondweed, and fanwort growth that were identified during a pretreatment survey. Reward (diquot) and Clipper (flumioxazin) were applied to 74 acres (Solitude 2017).
  • Water quality samples were collected, and blue/green cell counts were found to be 540 cells per milliliter (cells/mL), below the Massachusetts Department of Public Health contact threshold of 70,000 cells/mL (Solitude 2017).

Overall, there has been limited success in controlling the invasive plant population in the lake. It should be noted that the algal blooms prevent aquatic plants from growing. If the algal blooms are reduced and the water clarify improves, it is expected that the aquatic plant growth will increase substantially.  

6.4 Watershed-Wide BMPs

The major source of pollution, as determined in past studies and through observations during site investigation, is erosion from unpaved roads and from the slopes of paved roads. Erosion was observed throughout the watershed but is of particular concern around the lake on the “esker” roads. This erosion is both a water quality and safety issue, as the sediment is flowing directly into the lake, carrying nutrients with no attenuation from overland flow, and is eroding from under the road, causing concern regarding the structural integrity of the roads. As such, the watershed-wide BMPs that address erosion (e.g., slope stabilization and dirt road BMPs) should be prioritized. Erosion is also causing many catch basins throughout the watershed to be filled with sediment.

The following watershed-wide BMPs are proposed:

• Slope Stabilization off of Paved Roads. As discussed in the site visit summary, there is severe erosion at many of the paved roads throughout the watershed, especially at the “esker” roads directly adjacent to Lost Lake/Knops Pond. Roads in need of slope stabilization observed during the site visit include Island Road, Radio Road, Weymisset Road, Moose Trail, and Boat House Road, although there may be additional locations for slope stabilization within the watershed. There are several potential methods of slope stabilization, including reseeding with native plants and installing fabric filters (such as jute or geotextiles). While reseeding, it is important to be mindful of limiting fertilizer use, to avoid additional nutrient loading. There are three main components to the slope stabilization: topsoil, hydroseeding (including fertilizer), and an optional erosion control blanket. A cost estimate is shown in Table 6-2.

Table 6-2: Slope Stabilization Cost Estimates

Approximate Site Area (square feet)

Topsoil & Seeding

Topsoil, Seeding, & Erosion Control Blanket

	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)
500	$1,200 ($840 to $1,800)	$2.40  ($1.68 to $3.60)	$2,200  ($1,540 to $3,300)	$4.50 ($3.15 to $6.75)
2,000	$4,800  ($3,360 to $7,200)	$2.40 ($1.68 to $3.60)	$9,000  ($6,300 to $13,500)	$4.50 ($3.15 to $6.75)
10,000	$23,800  ($16,660 to $35,700)	$2.40  ($1.68 to $3.60)	$44,900  ($31,430 to $67,350)	$4.50 ($3.15 to $6.75)
50,000	$119,000 ($83,300 to $178,500)	$2.40  ($1.68 to $3.60)	$224,500 ($157,150 to $336,750)	$4.50  ($3.15 to $6.75)

• Dirt Road BMPs. Many of the dirt roads throughout the watershed showed signs of moderate to severe erosion, including Maplewood Avenue, Birchwood Avenue, Off Prescott Street, and Shattuck Street. The Massachusetts Unpaved Roads BMP Manual (MassDEP 2011) includes a variety of potential dirt road BMPs. Proposed solutions to dirt road erosion include maintaining natural buffers and drainage ways, general shoulder maintenance, and structural measures such as regrading roads, installing waterbars, and lining ditches. Figure 6-5 shows an example of two types of ditches.

 

Figure 6-5: Typical Ditch Detail (MassDEP 2011)

We recommend that GLA and GPAC coordinate with the Town of Groton on any dirt road-related projects or grant proposals.

• Catch Basin Maintenance and Structural BMPs. As described in the site visit summary, many catch basins throughout the watershed were filled with sediment due to erosion, including catch basins located on Maplewood Avenue, Shattuck Street, and Prescott Street. The catch basins should be cleaned in coordination with the Town of Groton. Stabilizing the dirt roads and slopes can help reduce erosion; however, in addition, small collection sumps and/or rain gardens can be installed upstream of drain inlets. The catch basin on Maplewood Avenue was filled with sediment and partially covered with concrete tiles. This catch basin should either be fully covered to prevent sediment from entering the sump and subsequently the drainpipes that discharge to Lost Lake/Knops Pond or opened to receive stormwater runoff. Modifications can also be made to the catch basin inlet and sump to better capture sediment to prevent discharge into the lake or its tributaries. Figure 6-6 shows an example of a catch basin filtration inlet system that removes sediment and oil from stormwater runoff (New Pig 2021).

 

Figure 6-6: Catch Basin Filtration Inlet System (New Pig 2021)

6.5 Site-Specific BMPs

We also identified several site-specific proposed management measures as opportunities to capture and slow runoff and reduce pollutant loading. The six site-specific BMPs are the Grotonwood Camp raingarden, the Boat Launch raingarden, the Boat Launch swale, the Birchwood Road swale, the Shattuck Street lot raingarden, and the Shattuck Street swale. The conceptual design sheets for the proposed BMPs are included as Appendix B. The site-specific BMPs should be implemented in conjunction with the site-specific BMPs, as it is unlikely that the site-specific BMPs alone will provide enough nutrient load removal to resolve the water quality issues within the watershed. The site-specific BMPs are described in more detail below:

• Grotonwood Camp Raingarden. The proposed raingarden will infiltrate stormwater runoff from the Grotonwood Camp main parking lot, a relatively large area of impervious surface for the watershed. Currently, there are signs of erosion at the edge of the forest where the stormwater runoff channelizes from the parking lot. The proposed raingarden would mitigate this erosion and provide stormwater quantity and quality benefits, such as reducing peak flows from the parking lot and reducing the nutrient and sediment load. Although the stormwater runoff does not discharge directly to a tributary or Lost Lake/Knops Pond, it discharges approximately 100 feet from a stream that runs through Grotonwood Camp.
• Boat Launch Raingarden. The proposed boat launch raingarden at the Lost Lake Public Boat Launch will infiltrate stormwater runoff from the boat launch parking lot, which is mostly paved. The Boat Launch Swale, described below, will treat stormwater runoff from the paved road (off Pine Trail) that leads down to the parking lot. Currently, there is significant erosion at the boat launch. Additionally, there is eutrophication in the pond directly adjacent to the boat launch, indicating excessive nutrient loads. Installing a raingarden at the boat launch would infiltrate stormwater runoff, reducing erosion, and mitigate the nutrient load that enters the lake directly.
• Boat Launch Swale. The proposed boat launch swale will work in conjunction with the raingarden described above. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loads from the road leading to the boat launch. The road is paved and moderately steep and there are signs of erosion on either side of it. As the stormwater runoff is already directed towards the sides of the road, installing a swale will provide water quality treatment instead of carrying nutrients and sediment towards the boat launch and subsequently to Lost Lake/Knops Pond, as is currently occurring due to channelized flow.
• Birchwood Avenue Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loading from Birchwood Road. Birchwood Avenue is a paved, steep, winding road with observed erosion at the outer edge where the road curves. The erosion is severe, with defined channels and gullies on the slope of the road. Stormwater runoff from Birchwood Avenue flows into the Unnamed Tributary that leads directly into Lost Lake/ Knops Pond.
• Shattuck Street Lot Raingarden. The proposed Shattuck Street Lot raingarden will infiltrate stormwater runoff from Shattuck Street and part of Scarlet Hill Farm. The proposed location is the parking lot for the public access trails at Scarlet Hill Farm that run adjacent to a stream that is a tributary for Lost Lake/Knops Pond. Although Scarlet Hill Farm has received awards for their manure practices, agricultural land tends to have higher pollutant loads than forested or open land.
• Shattuck Street Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff from Shattuck Street and the surrounding area and mitigate the nutrient loads. Like the Shattuck Street Lot raingarden, the drainage area for the swale also includes agricultural land at Scarlet Hill Farm. In addition, there is severe erosion on Shattuck Street, which is unpaved (gravel) with a moderately steep slope; therefore, installing the swale would reduce the erosion by reducing stormwater runoff and mitigate the associated nutrient load.

More information about the construction and operation and maintenance (O&M) of each type is included below.

Raingardens/Bioretention Areas (MassDEP 2016a):

• Raingardens use soil, plants, and microbes to treat stormwater before it infiltrates into the soil or is discharged. They can provide pollutant removal and infiltrate up to 1 inch of rainfall, in addition to providing groundwater recharge.
• Raingardens are comprised of shallow depressions with a layer of sandy soil, mulch, and planted with dense vegetation. Generally, they are designed to pond to a depth of water 6 to 8 inches deep. The soil mix should be sandy loam or loamy sand with a clay content of less than 15%.
• Soil and any eroded areas should be inspected monthly, and litter and debris should be removed accordingly. Invasive species should be removed as needed and mulch replaced every two years. With proper selection of plants, the need for fertilizers and pesticides should be eliminated or at least very minimal. This is especially important for the Lost Lake/Knops Pond watershed, as introducing additional nutrient loads would be detrimental to water quality and negate the use of the raingarden.

Treatment Swales (MassDEP 2016a):

• Water quality or treatment swales are vegetated open channels that convey runoff and treat the stormwater runoff.
• Soil characteristics, flow capacity, erosion resistance, and vegetation should be considered when designing a treatment swale.
• Swale maintenance includes inspecting swales to ensure vegetation health and lack of erosion (once per month initially, then twice per year); mow if necessary (as needed); remove sediment and debris manually (at least once per year), and re-seed as necessary).

6.6 Non-Structural BMPs and Watershed Outreach (Category 5)

Non-structural BMPs typically do not involve construction and are often more broadly applied throughout a watershed. Implementation of these BMPs can result in significant load reductions. Examples of non-structural BMPs include:

• Municipal “good housekeeping” practices such as street sweeping and leaf litter collection programs can reduce phosphorus loading by reducing transport of pollutants through stormwater systems.
• Regulations can be used to help affect behavior change and manage land uses practices; examples of regulatory tools include stormwater management regulations, septic system ordinances, fertilizer regulations, pet waste removal requirements, and more.
• Outreach and education can also be used to help change behavior and reduce pollutant loading by encouraging and promoting activities that reduce or prevent pollutant loading such as fertilizer reduction incentives, pet waste pick-up programs, pond-friendly landscaping workshops and more.
• Land conservation is a common tool that can be used to prevent loading from land conversion activities.

Table 6-3 summarizes potential non-structural BMPs that can be implemented throughout the watershed.

Table 6-3: Non-Structural BMPs

Non-Structural BMP	Description	Responsible Party
Fertilizer Program	Reduce the amount and frequency of fertilizer application[9] to pervious developed areas throughout the watershed.	Town of Groton; GPAC; GLA
Street Sweeping	Optimize street sweeping locations and frequency equivalent to two times a year sweeping (in Spring and Fall) of 50% of roads within 650-feet of the shoreline, using vacuum assisted sweeper.	Town of Groton
Leaf Litter Management	Provide leaf collection at least 4 times during October and November for properties within 650-feet of the shoreline. Within 24 hours of leaf collection, collect remaining leaf litter on paved streets using a cleaning machine, such as a mechanical broom or vacuum assisted street cleaner.	Town of Groton
Shoreline Buffer	Retrofit developed areas along shoreline with 20-ft-no-mow/no-alteration grassed buffer for properties within 425-feet of the shoreline.	Town of Groton
Regulations	Establish municipal regulations to enable and promote improved stormwater management, buffer protections, and shoreland controls.	Town Planning Staff
Land Conservation	Coordinate with groups to prioritize land conservation goals/target parcels to reduce future load associated with new development.	Town Planning Staff; GPAC; GLA
Impervious Disconnection	Direct runoff from impervious areas such as roadways, parking lots, and roofs, and discharge it to adjacent vegetated permeable surfaces that are of sufficient size with adequate soils to receive the runoff without causing negative impacts to adjacent down-gradient properties.	Town of Groton

Watershed outreach will take place through educational kiosks at the proposed raingardens. These kiosks will include information on water quality in Lost Lake/Knops Pond, the purpose of the stormwater BMPs and their impact on water quality, and actions residents can take to improve water quality in the watershed.

The target audiences include residents in the watershed, recreational users of Lost Lake/Knops Pond (boaters, beach-goers, etc.), and watershed organizations and other user groups (GLA, GPAC, etc.)

GLA and/or GPAC may coordinate with the Town of Groton on distribution of educational materials such as lawn and landscaping education, pet waste management, car washing, and other topics. GLA and/or GPAC may also use their mailing lists to distribute residential educational materials, such as resident pet waste information, septic system handouts, and handouts on residential yard care, found on Think Blue Massachusetts’s website (Think Blue Massachusetts | Residents).

7.0       Schedule and Milestones (Elements F and G)

The project schedule and milestones presented in this section will enable project partners to track management activities over time as the Last Lakes and Knops Pond Watershed-Based Plan is implemented.

Table 7-1 provides a preliminary schedule for implementation of recommendations provided by this WBP. It is expected that the WBP will be reevaluated and updated in 2024, or as needed, based on ongoing monitoring results and other efforts. New projects will be identified through future data analysis, and stakeholder engagement and will be included in updates to the implementation schedule.

 

 

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Structural & Nonstructural BMPs
Slope Stabilization 1 to 2 sites per year	Apply for 604b grant funding to prioritize sites and create conceptual designs.	Apply for Section 319 funding to implement BMPs.	Implement BMPs; Conduct annual maintenance on constructed BMPs; Apply for Section 319 funding for additional sites.
	12/1/2022	12/1/2023	12/1/2024
Dirt Road BMPs 1 road segment per year	Apply for Section 319 or 604b grant funding.	Improve 1 road segment per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Catch Basin Cleaning	Schedule meeting with Town of Groton to discuss catch basin cleaning schedule.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Maintenance	Schedule meeting with Town of Groton to discuss catch basin maintenance.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Inlet/Sump Modification	Apply for Section 319 or 604b grant funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Site-specific BMPs 1-2 per year based on prioritization matrix	Apply for Section 319 funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024

 

Public Education & Outreach
Install Educational Kiosk	Install educational kiosk with BMP construction.
	12/1/2023

 

Monitoring
Monitoring Plan	Conduct four sampling events per year[10].
	Annually

 

8.0       Success Indicators and Evaluation (Element H)

The water quality target concentration(s) is presented under Element A of this plan. To achieve this target concentration, the annual loading must be reduced to the amount described in Element B. Element C of this plan describes the various management measures that will be implemented to achieve this targeted load reduction. The evaluation criteria and monitoring program described below will be used to measure the effectiveness of the proposed management measures (described in Element C) in improving the water quality of Lost Lake/Knops Pond:

• Indirect Indicators of Load Reduction. Indicators of excessive nutrient load include moderate to severe erosion and eutrophication in ponds or in Lost Lake/Knops Pond itself. Therefore, the absence of erosion, especially close to Lost Lake/Knops Pond or its tributaries, and/or the absence of eutrophication will indicate successful load reduction. In addition, nuisance algae and vegetation monitoring in Lost Lake/Knops Pond can also indicate water quality trends.
• Direct Indicators (Measurements) of Load Reduction. Results of the water quality monitoring will also indicate progress towards nutrient load reduction, specifically a reduction in phosphorus in both the Unnamed Tributary and in Martins Pond Brook. See Element I for more information about the water quality monitoring plan.
• Project-Specific Indicators. As previously discussed, the absence of erosion and eutrophication will likely indicate success in reducing the nutrient load. Specifically, areas near constructed watershed-wide or structural BMPs will indicate that these projects are successful.
  • Number of BMPs Installed. Element C of this WBP recommendations the installation of structural BMPs at six locations and recommends several watershed-wide BMPs. The anticipated pollutant load reduction has been documented for each proposed BMP, and the number of BMPs installed will be tracked and quantified as part of this program. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning and slope stabilization).
• TMDL Criteria. Lost Lake/Knops Pond is not currently subject to a non-native aquatic plant TMDL; therefore, this criterion is not applicable. However, please note that Lost Lake/Knops Pond does have a Mercury in Fish Tissue TMDL.

9.0 Monitoring Plan (Element I)

This WBP recommends implementation of a volunteer water quality monitoring program. The purpose of the monitoring program is to refine the location of and quantify sources of pollution. Through previous studies and the site visit, sources of pollution are reasonably well known; however, monitoring would allow for source contributions to be evaluated and quantified spatially. Because this program will help identify priority sources, it will lead to more effective implementation of BMPs. Additionally, monitoring will allow for a quantitative measure of BMP effectiveness by comparing concentrations of TP, TN, and TSS before and after the implementation of BMPs.  Elements of the recommended monitoring plan are summarized below:

• The monitoring plan locations were chosen based on accessibility and proximity to suspected sources of pollution and nutrients. In terms of accessibility, sampling locations were chosen to be close to a road or street and not along steep slopes. An exception is the Martins Pond Brook inlet which may need to be accessed via private property or by boat. The sampling locations chosen are downstream of suspected sources of pollution and nutrients to target areas identified as contributing pollution and nutrients to the watershed, based on previous reports and the site visit. Figure 9-1 shows the proposed monitoring locations. The monitoring locations are described below.
  • Outlet of Martins Pond Brook. This area, currently conservation land, features historical agricultural use. Previous reports have identified Martins Pond Brook as a source of phosphorus (ESS 2017).
  • Martin’s Pond at Lowell Street. This upstream area has historical and current agricultural use (Scarlet Hill Farm). Additionally, the Lowell Street culvert is fairly accessible for sampling.
  • Martins Pond Brook Inlet. The sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations.
  • Unnamed Tributary Inlet. This sampling location was chosen to determine if residential and developed areas are contributing to the phosphorus load.
  • Unnamed Tributary at Boston Road. Like the Martins Pond Brook inlet, this sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations. The road crossing at this location provides accessibility.
• In-Lake Sampling. In-lake sampling is recommended to ensure that the in-lake phosphorus concentration remains below the target concentration of 50 ug/L. Samples could be taken at locations in Lost Lake/Knops Pond, specifically at the deepest locations (at multiple points in the water column) and at areas next to slopes noted for erosion due to stormwater runoff.
• At a minimum, sampling parameters should include TP, dissolved phosphorus, and total suspended solids.
• When to Sample. Sampling should be conducted during both dry and wet weather events to best capture the behavior of sources of pollution. A minimum of two dry and two wet weather events should be conducted annually in the fall, spring, and summer to assess temporal and seasonal trends.
• Quality Assurance/Quality Control (QA/QC). As the results from the volunteer monitoring program will be used for internal guidance only, developing a quality assurance project plan (QAPP) is not required. However, it should be noted that a QAPP is required to submit data to MassDEP and is recommended to help ensure data quality.
• Interpretation of Results/Data Analysis. The results of each sampling location should be compared both to the results of other sampling locations and to results from prior sampling events to determine seasonal trends, temporal trends, and/or the efficacy of any implemented solutions. By comparing the results at sampling locations upstream and downstream of each tributary, sources of pollution may be able to be determined. For example, comparing phosphorus results upstream and downstream of the forested area adjacent to the Martin’s Brook Pond tributary may help to determine if natural sources of phosphorus (i.e., leaf litter) are a large contributor to the overall phosphorus levels.
• Refinement of Monitoring Plan. Potential future changes to the monitoring plan include refining locations to pinpoint specific source areas; collecting runoff sampling from bare soil or agricultural areas if access is provided by the landowners; finger printing of inlet concentrations compared to solid soil data to further refine sources of pollution; additional in-lake or watershed septic source evaluations (e.g., DNA markets, advanced chemical indicators, nutrient isotopes); and additional in-lake monitoring at various depths throughout Lost Lake/Knops Pond.

 

 

Figure 9-1: Proposed Monitoring Locations.

10.0 Funding for Future Watershed Planning Phases and Implementation

10.1 Cost Estimate and Pollutant Load Reduction Estimates

Table 10-1 presents the estimated pollutant load reductions and costs for the proposed management measures.

 

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs[11].

Site-Specific BMP	Drainage Area (ac)	BMP Footprint (sf)/BMP Length (ft)	BMP Design Storm Depth (in)	Estimated Pollutant Removal			Estimated Annual O&M Costs[12]	Estimated Cost
				Total Phosphorus (lbs./year)	Total Nitrogen (lbs./year)	Total Suspended Solids (lbs./year)
Grotonwood Camp Raingarden	0.47	440 sf	0.5	0.5	4.0	191.2	$2,000	$21,200
Boat Launch Raingarden	0.47	405 sf	0.5	0.5	3.6	171.6	$2,000	$21,700
Boat Launch Swale	0.36	50 ft	0.5	0.1	0.1	42.2	$1,000	$12,800
Birchwood Avenue Swale	0.16	40 ft	0.5	0.1	0.2	45.5	$1,000	$5,700
Shattuck Street Lot Raingarden	1.23	445 sf	0.5	0.5	3.2	134.4	$2,000	$56,700
Shattuck Street Swale	0.36	60 ft	0.5	0.1	0.3	84.3	$1,000	$48,800

Note: ac is acres; sf is square feet; lbs./year is pounds per year; O&M is operation and maintenance.

Table 10-2 presents a priority matrix to guide future work and grant funding based on the following criteria:

• Cost/TP Removed. The estimated cost to construct the structural BMP divided by the pounds of total phosphorus removed per year to get a cost per pound of phosphorus removed.
• Cost/TN Removed. The estimated cost to construct the structural BMP divided by the pounds of total nitrogen removed per year to get a cost per pound of nitrogen removed.
• An evaluation of whether adequate space and topographical/geological conditions are available to construct the BMP (e.g., considering slope, soil type).
• Structural BMPs, especially raingardens with educational kiosks, can be used to educate the public about stormwater and water quality. Therefore, the visibility of each proposed structural BMP was considered (e.g., if it is in an often-used space, proximity to road).
• Public/Private. Constructing structural BMPs on public property tends to be more ideal than working with the landowner to install a BMP on private property.
• Proximity to Lake/Tributary. Structural BMPs installed close to the lake or a tributary will prevent nutrients and sediment from directly entering the lake without any attenuation. Therefore, these BMPs are prioritized.

The ranking is on a scale of one to five with five being the most optimal.

Table 10-2: Proposed Structural BMP Priority Matrix.

Structural BMP	Cost/TP Removed	Cost/TN Removed	Feasibility	Visibility	Public/ Private	Proximity to Lake/ Tributary	Sum	Rank
Slope Stabilization	4	4	4	3	5	5	25	High
Dirt Road BMPs	4	4	4	3	5	3	23	High
Catch Basin BMPs	5	5	5	1	5	3	24	High
Grotonwood Camp Raingarden	3	3	4	3	1	1	15	Low
Boat Launch Raingarden	3	1	3	4	5	5	21	High
Boat Launch Swale	5	5	4	3	5	4	26	High
Birchwood Avenue Swale	5	5	3	2	5	3	23	High
Shattuck Street Lot Raingarden	3	3	4	3	1	4	18	Medium
Shattuck Street Swale	4	4	4	2	5	3	22	High

Note: TP is total phosphorus and TN is total nitrogen.

10.2 Funding for Proposed Management Measures

The funding needed to implement the proposed site-specific BMPs (described in Element C) is presented in Table 10-3. The total cost for the program was estimated at $237,000 with estimated annual O&M costs of $14,500 or more. Table 10-3 presents the funding needed to implement the management measures presented in this watershed plan. The table includes costs for BMPs and operation and maintenance activities.

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan.

Management Measures	Location	Capital Costs[13]	Annual O&M Costs	Relevant Authorities	Technical Assistance Needed	Funding Needed[14]
Watershed-wide BMPs (from Element C)
Slope Stabilization - Reseeding	Watershed-wide	$23,800 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$23,800
Slope Stabilization – Reseeding & Fabric Filter	Watershed-wide	$44,900 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$44,900
Dirt Road BMPs	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Cleaning	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Maintenance	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Inlet/Sump Modification	Watershed-wide	$295 each plus labor costs	$1,475 for 5 replacement inserts plus labor	Town of Groton; GLA; GPAC	Permitting and Construction	$1,475 for 5 inserts plus permitting and labor costs
Site-specific BMPs (from Element C)
Bioretention and Rain Garden	Grotonwood Camp Raingarden	$21,216	$2,000	Town of Groton; Grotonwood Camp	Engineering Design and Construction	$21,216
Bioretention and Rain Garden	Boat Launch Raingarden	$21,676	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$21,676
Grassed Channel/Water Quality Swale	Boat Launch Swale	$12,811	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$12,811
Grassed Channel/Water Quality Swale	Birchwood Rd Swale	$5,693	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$5,693
Bioretention and Rain Garden	Shattuck Street Lot Raingarden	$56,727	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$56,727
Grassed Channel/Water Quality Swale	Shattuck Street Swale	$48,753	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$48,753
Information/Education (see Element E)
Monitoring and Evaluation (see Element H/I)
Total Funding Needed:						$237,000
Funding Sources:
MassDEP Section 319 and 604b Grants

11.0 Conclusions

As stated in Section 1.2 of this WBP, the long-term goal is to reduce total phosphorus and other nutrient and sediment loadings to Lost Lake/Knops Pond. The water quality goals (described in Section 5.2) will be accomplished through installation of BMPs throughout the watershed (described in Section 6.0) and will be measured through water quality monitoring efforts (described in Section 9.0). The action items for this WBP are described below.

• BMP Implementation. Implement BMPs throughout the watershed to achieve a 10% reduction in nutrient load as an interim goal. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons/yr. for TP, TN, and TSS, respectively.
• Grant Funding. Apply for MassDEP Section 319 and 604b grants[15] for implementation of BMPs and additional planning, such as determining sites for slope stabilization.
  • Section 319 Nonpoint Source Grant. This program is used for implementation projects that address the prevention, control, and abatement of nonpoint source pollution. Generally, eligible projects must implement measures that target the major source(s) of nonpoint source pollution within a watershed, contain an appropriate method for evaluating the project results, and must address activities identified in the Massachusetts NPS Management Plan.
  • Section 604b Nonpoint Source Grant. This program is used for eligible entities to conduct watershed based nonpoint source assessment and planning projects that result in the following: development of preliminary designs and implementation plans that will address water quality impairments in impaired watersheds, determination of the nature, extent, and causes of water quality problems, and determination of pollutant loads necessary to meet water quality standards.
• Indicators of Success. The monitoring program and other indicators will be used to measure the effectiveness of the implemented BMPs.
  • Monitoring Program (Direct Measurements). Results of the water quality monitoring will indicate progress towards nutrient load reduction.
  • Indirect Indicators. Indirect indicators include the absence of eutrophication in ponds in the watershed and in Lost Lake/Knops Pond and the absence of erosion throughout the watershed. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning).
  • Project Specific Indicators. The number of BMPs installed will be tracked and quantified as part of this WBP.
• Long-Term Goals. The long-term goals will be adapted based on the results of the water quality monitoring and the indicators of success.

 

•  

12.0 References

314 CMR 4.00. 2013. Division of Water Pollution Control, Massachusetts Surface Water Quality Standards. https://www.arcgis.com/home/item.html?id=be2124509b064754875b8f0d6176cc4c.

ArcGIS. 2020a. USA Soils Hydrologic Group. Imagery Layer.

ArcGIS. 2020b. “USA Soils Water Table Depth.” Imagery Layer.

Cohen, A. J. and A. D. Randall. 1998. Mean annual runoff, precipitation, and evapotranspiration in the glaciated northeastern United States, 1951-80. Prepared for United States Geological Survey, Reston VA.

Geosyntec. 2014. Least Cost Mix of BMPs Analysis, Evaluation of Stormwater Standards Contract No. EP-C-08-002, Task Order 2010-12. Prepared for Jesse W. Pritts, Task Order Manager, U.S. Environmental Protection Agency.

Geosyntec. 2015. Appendix B: Pollutant Load Modeling Report, Water Integration for the Squamscott-Exeter (WISE) River Watershed.

 GLA. 2012. Lost Lake/Knops Pond Resource Management Plan. Prepared by Groton Lakes Association. Revision 4.01. August 12, 2012.

King, D. and P. Hagan. 2011. Costs of Stormwater Management Practices in Maryland Counties. University of Maryland Center for Environmental Science Chesapeake Biological Laboratory. October 11, 2011.

Leisenring, M., J. Clary, and P. Hobson. 2014. International Stormwater Best Management Practices (BMP) Database Pollutant Category Statistical Summary Report: Solids, Bacteria, Nutrients and Metals. Geosyntec Consultants, Inc. and Wright Water Engineers, Inc. December 2014.

Massachusetts Department of Revenue Division of Local Services. 2016. Property Type Classification Codes, Non-arm’s Length Codes and Sales Report Spreadsheet Specifications. June 2016.  https://www.mass.gov/files/documents/2016/08/wr/classificationcodebook.pdf

MassDEP. 2001. The Massachusetts Unpaved Roads BMP Manual. Prepared by Berkshire Regional Planning Commission and prepared for Massachusetts Department of Environmental Protection and U.S. Environmental Protection Agency. Winter 2001.

MassDEP. 2012. Massachusetts Year 2012 Integrated List of Waters Final Listing of Massachusetts' Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act.

MassDEP. 2016a. Massachusetts Clean Water Toolkit.

MassDEP. 2016b. Massachusetts Stormwater Handbook, Vol. 2, Ch. 2, Stormwater Best Management Practices.

MassDEP. 2019. Massachusetts Year 2016 Integrated List of Waters Final Listing of Massachusetts’ Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act. December 2019.

MassGIS. 1999. Networked Hydro Centerlines. Shapefile.

MassGIS. 2001. USGS Topographic Quadrangle Images. Image.

MassGIS. 2005. Elevation (Topographic) Data (2005). Digital Elevation Model.

MassGIS. 2007. Drainage Sub-basins. Shapefile.

MassGIS. 2009a. Impervious Surface. Image.

MassGIS. 2009b. Land Use (2005). Shapefile.

MassGIS. 2012. 2010 U.S. Census Environmental Justice Populations. Shapefile.

MassGIS. 2013. MassDEP 2012 Integrated List of Waters (305(b)/303(d)). Shapefile.

MassGIS. 2015a. Fire Stations. Shapefile.

MassGIS. 2015b. Police Stations. Shapefile.

MassGIS. 2017a. Town and City Halls. Layer.

MassGIS. 2017b. Libraries. Layer.

MassGIS. 2020. Massachusetts Schools (Pre-K through High School). Data layer.

MassGIS. 2021. Standardized Assessors’ Parcels. Mapping Data Set.

New Pig. 2021. “PIG® Oil & Sediment Catch Basin Filtration System – Large.” < Storm Drain Filter Insert for Oil & Sediment – New Pig>. Accessed November 19, 2021.

Solitude Lake Management. 2017. Annual Report 2017 Aquatic Vegetation Management Program Lost Lake & Knops Pond. Prepared for Groton Lakes Associated & Town of Groton. December 2017.

Schueler, T.R., L. Fraley-McNeal, and K. Cappiella. 2009. “Is impervious cover still important? Review of recent research.” Journal of Hydrologic Engineering 14 (4): 309-315.

United States Bureau of Labor Statistics. 2016. Consumer Price Index.

United States Geological Survey. 2016. National Hydrography Dataset, High Resolution Shapefile.

University of Massachusetts, Amherst. 2004. Stormwater Technologies Clearinghouse.

USDA NRCS and MassGIS. 2012. NRCS SSURGO-Certified Soils. Shapefile.

USEPA. 1986. “Quality Criteria for Water (Gold Book).” EPA 440/5-86-001. Office of Water, Regulations and Standards. Washington, D.C.

USEPA. 2010. EPA's Methodology to Calculate Baseline Estimates of Impervious Area (IA) and Directly Connected Impervious Area (DCIA) for Massachusetts Communities.

Voorhees, Mark, USEPA. 2015. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

Voorhees, Mark, USEPA. 2016a. “FW: EPA Region 1 SW BMP performance equations.” Message to Chad Yaindl, Geosyntec Consultants. January 25, 2016. E-mail.

Voorhees, Mark, USEPA. 2016b. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

 

Water Quality Assessment Reports

“Merrimack River Watershed 2004 Water Quality Assessment Report”

 

 

TMDL

No TMDL Found

 

 

 

 

 

 

 

 

APPENDICES

Appendix A – Pollutant Load Export Rates (PLERs)

 

Land Use & Cover1	PLERs (lb./acre/year)
	(TP)	(TSS)	(TN)
AGRICULTURE, HSG A	0.45	7.14	2.59
AGRICULTURE, HSG B	0.45	29.4	2.59
AGRICULTURE, HSG C	0.45	59.8	2.59
AGRICULTURE, HSG D	0.45	91.0	2.59
AGRICULTURE, IMPERVIOUS	1.52	650	11.3
COMMERCIAL, HSG A	0.03	7.14	0.27
COMMERCIAL, HSG B	0.12	29.4	1.16
COMMERCIAL, HSG C	0.21	59.8	2.41
COMMERCIAL, HSG D	0.37	91.0	3.66
COMMERCIAL, IMPERVIOUS	1.78	377	15.1
FOREST, HSG A	0.12	7.14	0.54
FOREST, HSG B	0.12	29.4	0.54
FOREST, HSG C	0.12	59.8	0.54
FOREST, HSG D	0.12	91.0	0.54
FOREST, HSG IMPERVIOUS	1.52	650	11.3
HIGH DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
HIGH DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
HIGH DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
HIGH DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
HIGH DENSITY RESIDENTIAL, IMPERVIOUS	2.32	439	14.1
HIGHWAY, HSG A	0.03	7.14	0.27
HIGHWAY, HSG B	0.12	29.4	1.16
HIGHWAY, HSG C	0.21	59.8	2.41
HIGHWAY, HSG D	0.37	91.0	3.66
HIGHWAY, IMPERVIOUS	1.34	1,480	10.2
INDUSTRIAL, HSG A	0.03	7.14	0.27
INDUSTRIAL, HSG B	0.12	29.4	1.16
INDUSTRIAL, HSG C	0.21	59.8	2.41
INDUSTRIAL, HSG D	0.37	91.0	3.66
INDUSTRIAL, IMPERVIOUS	1.78	377	15.1
LOW DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
LOW DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
LOW DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
LOW DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
LOW DENSITY RESIDENTIAL, IMPERVIOUS	1.52	439	14.1
MEDIUM DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
MEDIUM DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
MEDIUM DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
MEDIUM DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
MEDIUM DENSITY RESIDENTIAL, IMPERVIOUS	1.96	439	14.1
OPEN LAND, HSG A	0.12	7.14	0.27
OPEN LAND, HSG B	0.12	29.4	1.16
OPEN LAND, HSG C	0.12	59.8	2.41
OPEN LAND, HSG D	0.12	91.0	3.66
OPEN LAND, IMPERVIOUS	1.52	650	11.3
1HSG = Hydrologic Soil Group

 

Note: PLER is pollutant load export rate; lb./acre/year is pounds per acre per year; TP is total phosphorus; TSS is total suspended solids; and TN is total nitrogen.

 

 

 

Appendix B – Conceptual Design Sheets

 

[1] https://www.epa.gov/nps/handbook-developing-watershed-plans-restore-and-protect-our-waters

[2] Watersheds are defined by the WBP-tool by using MassGIS drainage sub-basins.

[3]Sources: MassGIS 1999, MassGIS 2001, USGS 2016

[4] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[5] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[6] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[7] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[8] Sources: MassGIS (2015a), MassGIS (2015b), MassGIS (2017a), MassGIS (2017b), MassGIS (2020), MA Department of Revenue Division of Local Services (2016), MassGIS (2005), ArcGIS (2020), MassGIS (2009b), MassGIS (2012), ArcGIS (2020b).

[9] Note: Massachusetts law limits phosphorus in lawn fertilizer.

[10] See Element I for additional monitoring plan information.

[11] The planning level cost estimates, pollutant load reduction estimates, and estimates of the BMP footprint were based off information obtained in the following sources and were also adjusted to 2016 values using the Consumer Price Index (United States Bureau of Labor Statistics 2016): Geosyntec Consultants, Inc. (2014, 2015), King and Hagen (2011), Leisenring, et al. (2014), MassDEP (2016a, 2016b), University of Massachusetts, Amherst (2004), Vorhees (2015, 2016a, 2016b).

[12] O&M costs are based on professional judgement, may vary significantly, and are subject to change.

[13] Estimated costs are AACE Level 4 conceptual level costs and may vary significantly.

[14] Funding needed value does not include annual operation & maintenance costs.

[15]Grants & Financial Assistance: Watersheds & Water Quality | Mass.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Town of Groton, MA

in coordination with

Groton Lakes Association

and the

Great Pond Advisory Committee

 

Cover Photo: Lost Lake Boat Ramp Photo Credit: Geosyntec Consultants, Inc.

 

Acknowledgements

The purpose of a Massachusetts Watershed-Based Plan (WBP) is to organize information about Massachusetts' watersheds and present the information in a format that will enhance the development and implementation of projects to restore water quality and beneficial uses in the Commonwealth. The Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was developed by Geosyntec under the direction of Alex Woodle with funding, input, and collaboration from Groton Lakes Association (GLA) and Great Ponds Advisory Committee (GPAC). This WBP was developed using funds from the Community Preservation Act (CPA) and using the Massachusetts Department of Environmental Protection’s (MassDEP’s) Watershed-Based Planning Tool (WBP Tool).

GLA has a goal of preserving and improving the lakes in eastern Groton, including Lost Lake/ Knops Pond. GLA conducts a variety of volunteer events and has been involved with removal of invasive plants and weeds in the lake.

As a nine-member committee in the Town of Groton, GPAC members work on weed management in the lake and make recommendations to the Select Board. Like the GLA, they deal with issues relating to lake management, including health, safety, water quality, and environmental protection.

The following individuals and organizations have contributed invaluable assistance and support for this project:

Core Stakeholders

Alexander Woodle, member of GPAC and GLA

GPAC

GLA

Grotonwood Camp

Gibbet Hill/Weber Restaurant Group

Groton Country Club

Tom Delaney – Director of Public Works (Groton)

 

Project Team

Alexander Woodle, GPAC, GLA

Adam Questad, PE, Geosyntec Consultants, Inc.

Renee Bourdeau, PE, Geosyntec Consultants, Inc.

Julia Keay, PE, Geosyntec Consultants, Inc.

Emma Williamson, EIT, Geosyntec Consultants, Inc.

 

 

Table of Contents

 

Acknowledgements. i

List of Tables. iv

List of Figures. v

Acronyms and Abbreviations. vi

Watershed-Based Plan Background. 1

Incorporating USEPA’s Nine Elements. 1

1.0         Introduction. 3

1.1 Data Sources. 3

1.2 Goal Statement 3

1.3 Plan Development Process. 4

2.0         Characteristics of Lost Lake and Knops Pond. 4

2.1 Land Use. 7

2.2 Impervious Cover 9

3.0         Assessment of Water Quality. 11

3.1 Water Quality Impairments. 11

3.2 Water Quality Goals. 12

3.3 TMDL Pollutant Load Criteria. 14

4.0         Water Quality Summary (Element A) 14

4.1 Additional Water Quality Information. 14

5.0         Water Quality Goals for Lost Lake and Knops Pond (Element B) 35

5.1 Estimated Pollutant Loads. 35

5.2 Water Quality Goals. 37

6.0         Management Actions to Control Phosphorus (Elements C, D, and E) 39

6.1 BMP Hotspot Map. 41

6.2 Field Watershed Investigation. 45

6.3 Existing Management Measures. 48

6.4 Watershed-Wide BMPs. 48

6.5 Site-Specific BMPs. 51

6.6 Non-Structural BMPs and Watershed Outreach (Category 5) 53

7.0         Schedule and Milestones (Elements F and G) 54

8.0         Success Indicators and Evaluation (Element H) 56

9.0 Monitoring Plan (Element I) 57

10.0      Funding for Future Watershed Planning Phases and Implementation. 60

10.1 Cost Estimate and Pollutant Load Reduction Estimates. 60

10.2 Funding for Proposed Management Measures. 61

11.0      Conclusions. 63

12.0      References. 64

Appendix A – Pollutant Load Export Rates (PLERs) 68

Appendix B – Conceptual Design Sheets. 70

 

 

 

 

List of Tables

Table 1: USEPA’s Nine Elements of Watershed Planning

Table 2-1: General Watershed Information

Table 2-2: Watershed Land Uses

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Table 3-3: Surface Water Quality Classification by Assessment Unit

Table 3-4: Water Quality Goals

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion

Table 4-2: Dry Weather Water Quality Parameters

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites

Table 4-5: Groundwater Nutrient Analysis

Table 4-6: Water Quality Data

Table 4-7: Tributary Water Quality Data

Table 4-8: Well Water Quality Data

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants

Table 5-2: Pollutant Load Reductions Needed

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis

Table 6-2: Slope Stabilization Cost Estimates

Table 6-3: Non-Structural BMPs

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs

Table 10-2: Proposed Structural BMP Priority Matrix

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan

 

 

List of Figures

Figure 2-1: Watershed Boundary Map

Figure 2-2: Watershed Land Use Map

Figure 2-3: Watershed Impervious Surface Map

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations

Figure 4-2: Erosion and Point Source Sampling Locations

Figure 4-3: Groundwater Seepage Sampling Locations

Figure 4-4: Sampling Locations

Figure 4-5: Pore Water Nitrate Concentrations

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations

Figure 4-7: Deep Hole Phosphorus Levels

Figure 4-8: Deep Hole Dissolved Oxygen Levels

Figure 4-9: Deep Hole Chlorophyll-a Levels

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation

Figure 4-11: Tributary Phosphorus Concentrations

Figure 4-12: Sampling Stations

Figure 4-13: Photos from GLA Presentation

Figure 6-1: Proposed BMP Locations

Figure 6-2: BMP Hotspot Map

Figure 6-3: Erosion Off Paved Roads

Figure 6-4: Erosion on Unpaved Roads

Figure 6-5: Typical Ditch Detail

Figure 6-6: Catch Basin Filtration Inlet System

Figure 9-1: Proposed Monitoring Locations

 

 

 

Acronyms and Abbreviations

AACE	Association for the Advancement of Cost Engineering
BMP	Best Management Practice
°C	Celsius
CEI	Comprehensive Environmental, Inc.
cells/mL	cells per milliliter
CPI	Consumer Price Index
DCIA	Directly Connected Impervious Areas
DO	Dissolved Oxygen
USEPA	United States Environmental Protection Agency
ET	Evapotranspiration
FC	Fecal Coliform
FS	Fecal Streptococci
GIS	Geographic Information System
GLA	Groton Lakes Association
GPAC	Great Ponds Advisory Committee
lbs.	pounds
lbs./acre/yr.	pounds per acre per year
lbs./yr.	pounds per year
MassDEP	Massachusetts Department of Environmental Protection
mg/L	milligrams per liter
µg/L	microgram per liter
ml	milliliter
NPS	Nonpoint Source
NRCS	National Resource Conservation Service
O&M	Operation and Maintenance
P	precipitation
PLER	Pollutant Load Export Rate
ppb	parts per billion
QAPP	Quality Assurance Project Plan
QA/QC	Quality Assurance / Quality Control
R	Runoff Depth
TIA	Total Impervious Area
TKN	Total Kjeldahl Nitrogen
TMDL	Total Maximum Daily Load
TN	Total Nitrogen
tons/year	tons per year
TP	Total Phosphorus
TSS	Total Suspended Solids
USDA	U.S. Department of Agriculture
USGS	U.S. Geological Survey
WBP	Watershed-Based Plan

 

Watershed-Based Plan Background

A Massachusetts Watershed-Based Plan (WBP) organizes information about a Massachusetts watershed and presents the information in a format that supports the development and implementation of projects to restore water quality and beneficial uses. A Massachusetts WBP follows the United States Environmental Protection Agency’s (USEPA's) recommended format for “nine-element” watershed plans.

This WBP was prepared for the Lost Lake/Knops Pond watershed in the town of Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). There are two main tributaries: Martins Pond Brook and an Unnamed Tributary.

Incorporating USEPA’s Nine Elements

The Lost Lake/Knops Pond Watershed-Based Plan includes nine criteria[1] for restoring waters impaired by nonpoint source (NPS) pollution. In this plan, the criteria will be called Elements A through I. These guidelines set forth by USEPA, highlight important steps in protecting water quality for waterbodies impacted by human activities and include specific recommendations for guiding future development, as well as strategies for reducing the cumulative impacts of NPS pollution on water quality. The nine criteria are as follows:

1. Identify causes and sources of pollution: The plan must identify the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated herein (and to achieve any other watershed goals identified in the watershed-based plan), as discussed in Element B immediately below. Sources that need to be controlled should be identified at the significant subcategory level with estimates of the extent to which they are present in the watershed (e.g., X numbers of dairy cattle feedlots needing upgrading, including a rough estimate of the number of cattle per facility; Y acres of row crops needing improved nutrient management or sediment control; or Z linear miles of eroded stream bank needing remediation).
2. Estimate pollutant loading into the watershed and the expected load reductions: The plan must estimate the load reductions expected for the management measures described under Element C below (recognizing the natural variability and the difficulty in precisely predicting the performance of management measures over time). Estimates should be provided at the same level as in Element A above (e.g., the total load reduction expected for dairy cattle feedlots; row crops; or eroded stream banks).
3. Describe management measures that will achieve load reductions and targeted critical areas: The plan must describe the NPS management measures that will be implemented to achieve the load reductions estimated under Element B above (as well as to achieve other watershed goals identified in this watershed-based plan), and an identification, using a map or a description, of the critical areas in which those measures will be needed to implement this plan.
4. Estimate amounts of technical and financial assistance and the relevant authorities needed to implement the plan: The plan must contain estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, for implementation. As sources of funding, states should consider Section 319 programs, State Revolving Funds, USDA’s Environmental Quality Incentives Program and Conservation Reserve Program, and other relevant federal, state, local, and private funds.
5. Develop an information/education component: An information/education component will enhance public understanding of the project and encourage early and continued public participation in selecting, designing, and implementing the NPS management measures.
6. Develop a project schedule: A schedule for implementing the NPS management measures identified in this plan will be established.
7. Describe the interim, measurable milestones: The plan will set forth interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented.
8. Identify indicators to measure progress: The plan will include set of criteria to determine whether loading reductions are being achieved over time and whether substantial progress is being made towards attaining water quality standards. In the case that reductions are not achieved, or progress is not made, criteria will also be established for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised.
9. Develop a monitoring component: A monitoring component will evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under Element H immediately above.

The primary goal of this WBP is to assess the Lost Lake/Knops Pond watershed and provide a plan for implementing actions that will result in measurable improvements in water quality. To achieve this goal, this WBP was developed to include the following nine elements in conformance with USEPA guidance discussed above.

Table 1: USEPA’s Nine Elements of Watershed Planning

Element	Plan Section	Element Description
A	4.0	Identify causes and sources of pollution
B	5.0	Estimate pollution load reductions needed for restoration
C	6.0	Identify actions needed to reduce pollution
D	6.0	Estimate costs and authority to implement restoration actions
E	6.0	Implement outreach and education to support restoration
F	7.0	Restoration schedule
G	7.0	Milestones—interim measures to show implementation progress
H	8.0	Success indicators and evaluation—criteria to show restoration success
I	9.0	Monitoring plan

 

1.0       Introduction

The Lost Lake/Knops Pond WBP describes water quality conditions, watershed characteristics, and sources of phosphorus loading to Lost Lake/Knops Pond. The WBP also establishes water quality goals, proposes best management practices (BMPs) for reducing nutrient loading, and estimates associated costs.

The overall goals of the Lost Lakes/Knops Pond WBP are as follows:

• Identify and quantify sources of nutrient loading to the lake
• Establish water quality goal(s) for the watershed
• Propose BMPs to reduce nutrient loading

The adaptive management approach described in the plan allows project partners flexibility in implementing BMPs. Additionally, the plan recognizes that improvements in water quality cannot be achieved with a single BMP and that results are typically not immediate. The proposed water quality monitoring will help guide the approach and quantify the impacts of implemented BMPs.

1.1 Data Sources

This WBP was developed using data sources provided by the Massachusetts Department of Environmental Protection (MassDEP). Additional data sources were reviewed and are described in subsequent sections of this WBP and listed below:

• Lost Lake Watershed Management Plan (ESS Group Inc. 2017)
• Aquatic Vegetation Program 2017 Annual Report, Solitude Lake Management (Solitude 2017)
• Lost Lake Water Quality Investigation Report, Comprehensive Environmental, Inc. (CEI 2013)
• A Diagnostic/Feasibility Study for the Management of Lost Lake/ Knopps [sic] Pond (Baystate Environmental Engineers 1989)
• Lost Lake/Knops Pond Resources Management Plan (GLA 2012)
• Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

1.2 Goal Statement

The long-term goal of this WBP is to reduce total phosphorus (TP) and other nutrient and sediment loadings to Lost Lake/Knops Pond. These pollutant load reductions may result in improvements to water quality conditions in Lost Lake/Knops Pond, as well as reducing the occurrence of eutrophication.

This goal will be accomplished primarily through installation of BMPs to capture runoff while reducing erosion and related nutrient and sediment loading to Lost Lake/Knops Pond from areas near the lake and from its two main tributaries. BMPs are proposed at multiple locations throughout the watershed.

1.3 Plan Development Process

This WBP was developed through collaboration during project management team meetings and conference calls primarily between Geosyntec, Alexander Woodle, and other members of GPAC and GLA.

An iterative process was used to develop the WBP, as outlined below:

• The Project Team (from Geosyntec Consultants, Inc.) first collected and reviewed existing data from the GLA and the GPAC and other available sources.
• A meeting was held on August 12, 2021 to solicit input and information about the Lost Lake/Knops Pond watershed and to identify possible sources of pollution, existing BMP projects, potential BMP opportunity locations, water quality goals, and public outreach activities.
• The Project Team then visited the site on August 30, 2021 to gather data on problem areas and potential BMP opportunity sites.
• A meeting was held on October 21, 2021 to update stakeholders regarding the site visit and to solicit feedback on proposed strategies to improve the water quality within the watershed.
• A WBP was drafted and reviewed by GPAC and GLA.
• The WBP was finalized based on GPAC and GLA input.

2.0       Characteristics of Lost Lake and Knops Pond

This WBP was prepared for the Lost Lake/Knops Pond watershed, in Groton, Massachusetts. The total drainage area of the Lost Lake/Knops Pond watershed is approximately 3,100 acres (roughly 5 square miles). The watershed is mostly forested, with low density residential areas near the lake and agricultural land use in the northwest portion of the watershed. Historically, the land use in the watershed was predominantly agricultural, especially in the northwestern part of the watershed near Martins Brook Pond. Now, activities in the watershed are mostly recreational (e.g., boating, swimming, and fishing on the lake) and agricultural (small farms in the northwest part of the watershed).

Lost Lake and Knops Pond, collectively referred to as Lost Lake/Knops Pond is one water body with two parts. The Lost Lake is the northern section and Knops Pond is the southern section. They join at the area between Ridgewood Road and Radio Road.

There are two main inlets to the lake: Martins Brook that discharges from Martins Brook Pond into the north of the lake and a shorter unnamed tributary that discharges into the west side of the lake. The lake discharges into Whitney Pond to the northeast.

Table 2-1 presents the general watershed information for the Lost Lake/Knops Pond watershed[2] and Figure 2-1 includes a map of the watershed boundary (Mass Geographic Information Systems (GIS) 2001).

Table 2-1: General Watershed Information

Watershed Name (Assessment Unit ID):	Lost Lake/Knops Pond (MA84084)
Major Basin:	Merrimack
Watershed Area:	3,099.3 acres
Water Body Size:	186 acres

Figure 2-1: Watershed Boundary Map[3]

Ctrl + Click on the map to view a full-sized image in your web browser

 

2.1 Land Use

Land use in the Lost Lake/Knops Pond watershed is mostly forested and accounts for approximately 65 percent (%) of the watershed; approximately 12% of the watershed is low density residential; approximately 9% of the watershed is water; approximately 7% of the watershed is agriculture; approximately 4% of the watershed is open land; approximately 2% of the watershed is high density residential; approximately 1% of the watershed is medium density residential; less than 1% of the watershed is commercial or industrial; and 0% of the watershed is designated as highway (Table 2-2; Figure 2-2). Roadways are included in the residential percentages.

A large portion of the residential area is located around Lost Lake/Knops Pond. The area is mostly low density residential, with more developed areas to the northeast of the lake, off Lost Lake Drive. There is a large, forested area north of the lake and agricultural areas (small farms, including cattle and horse farms) in the northwest portion of the watershed.

Table 2-2: Watershed Land Uses

Land Use	Area (acres)	Percent of Watershed
Forest	2,010	64.9
Low Density Residential	383	12.3
Water	285	9.2
Agriculture	204	6.6
Open Land	113	3.6
High Density Residential	51	1.7
Medium Density Residential	31	1.0
Commercial	22	0.7
Highway	0	0.0
Industrial	0	0.0

 

Figure 2-2: Watershed Land Use Map[4]

Ctrl + Click on the map to view a full-sized image in your web browser

2.2 Impervious Cover

There is a strong link between impervious land cover and stream water quality. Impervious cover includes surfaces that prevent the infiltration of water into the ground, such as paved roads and parking lots, roofs, and basketball courts. Most of the impervious cover in the watershed is associated with roads (Figure 2-3).

Impervious areas that are directly connected (DCIA) to receiving waters (via storm sewers, gutters, or other impervious drainage pathways) produce higher runoff volumes and transport stormwater pollutants with greater efficiency than disconnected impervious areas, which are surrounded by vegetated, pervious land. Runoff from disconnected impervious areas is reduced as stormwater flows across adjacent pervious surfaces and infiltrates.

Estimated DCIA for the watershed was calculated using Sutherland equations. USEPA provides guidance (USEPA 2010) on the use of these equations to predict relative levels of connection and disconnection based on the type of stormwater infrastructure within the total impervious area (TIA) of a watershed. Within each subwatershed, the total area of each land use was summed and used to calculate the percent TIA. The estimated TIA and DCIA for the Lost Lake/Knops Pond watershed is 5.7% and 3.6%, respectively.

Although the estimated TIA in the Lost Lake/Knops Pond watershed falls in the 0% and 10% range that typically denotes high quality, this estimation does not account for erosion on unpaved roads or on the slopes of paved roads, that has led to pollution within the lake. The relationship between TIA and water quality can generally be categorized as shown in Table 2-3 (Schueler et al. 2009):

Table 2-3: Relationship between Total Impervious Area (TIA) and Water Quality (Schueler et al. 2009)

Percent Watershed Impervious Cover	Stream Water Quality
0–10	Typically, high quality, and typified by stable channels, excellent habitat structure, good to excellent water quality, and diverse communities of fish and aquatic insects.
11–25	Clear signs of degradation. Elevated storm flows begin to alter stream geometry, with evident erosion and channel widening. Stream banks become unstable, and physical stream habitat is degraded. Stream water quality shifts into the fair/good category during storms and dry weather. Stream biodiversity declines to fair levels, with most sensitive fish and aquatic insects disappearing from the stream.
26–60	Typically, no longer supportive of a diverse stream community. The stream channel becomes highly unstable, and many stream reaches experience severe widening, downcutting, and streambank erosion. Pool and riffle structure needed to sustain fish is diminished or eliminated and the substrate no longer provides habitat for aquatic insects or spawning areas for fish. Biological quality is typically poor, dominated by pollution tolerant insects and fish. Water quality is consistently fair to poor, and water recreation is often no longer possible due to high bacteria levels.
>60	These streams are typical of “urban drainage,” with most ecological functions greatly impaired or absent, and the stream channel primarily functioning as a conveyance for stormwater flows.

 

Figure 2-3: Watershed Impervious Surface Map[5]

Ctrl + Click on the map to view a full-sized image in your web browser

3.0       Assessment of Water Quality

The goals of this WBP are founded upon the State’s water quality goals and criteria, which specify the indicators by which water quality improvements are measured. This section is an overview of the standards and criteria that apply to Lost Lake/Knops Pond.

3.1 Water Quality Impairments

Known water quality impairments are documented in MassDEP’s 2016 Massachusetts Integrated List of Waters (MassDEP 2019). The impairment categories from this document are set forth in Table 3-1, and water quality impairments are listed in Table 3-2.

Table 3-1: 2016 Massachusetts Integrated List of Waters Categories

Integrated List Category	Description
1	Unimpaired and not threatened for all designated uses
2	Unimpaired for some uses and not assessed for others
3	Insufficient information to make assessments for any uses
4	Impaired or threatened for one or more uses, but not requiring calculation of a Total Maximum Daily Load (TMDL), including: 4A: TMDL is completed 4B: Impairment controlled by alternative pollution control requirements 4C: Impairment not caused by a pollutant—TMDL not required
5	Impaired or threatened for one or more uses and requiring preparation of a TMDL

 

Table 3-2: 2016 Massachusetts Integrated List of Waters Categories Water Quality Impairments

Assessment Unit ID	Waterbody	Integrated List Category	Designated Use	Impairment Cause	Impairment Source
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Atmospheric Deposition—Toxics
MA84084	Lost Lake/Knops Pond	4A	Fish Consumption	Mercury in Fish Tissue	Source Unknown
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Eurasian Water Milfoil, Myriophyllum spicatum[6]	Introduction of Nonnative Organisms (Accidental or Intentional)
MA84084	Lost Lake/Knops Pond	4A	Fish, other Aquatic Life and Wildlife	Nonnative Aquatic Plants[7]	Introduction of Nonnative Organisms (Accidental or Intentional)

 

3.2 Water Quality Goals

Water quality goals may be established for many purposes, including the following:

1. Forwater bodies with known impairments, aTotal Maximum Daily Load (TMDL) is established by MassDEP and USEPA as the maximum amount of the target pollutant that the waterbody can receive and still safely meet water quality standards. If the waterbody has a TMDL for total phosphorus (TP), total nitrogen (TN), or total suspended solids (TSS), that information is provided below and included as a water quality goal.
2. Forwater bodies without a TMDL for TP, a default water quality goal for TP is based on target concentrations established in theQuality Criteria for Water (USEPA 1986; also known as the “Gold Book”). The Gold Book states that TP should not exceed 50 micrograms per liter (µg/L) in any stream at the point where it enters any lake or reservoir, nor 25 µg/L within a lake or reservoir. For the purposes of developing WBPs, MassDEP has adopted a TP target of 50 µg/L for all streams at their downstream discharge point, regardless of which type of water body the stream discharges to.
3. Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013) prescribe the minimum water quality criteria required to sustain a waterbody’s designated uses. Lost Lake/Knops Pond is a Class B waterbody. The water quality goal for fecal coliform bacteria is based on the Massachusetts Surface Water Quality Standards.

Table 3-3: Surface Water Quality Classification by Assessment Unit

Assessment Unit ID	Waterbody	Class
MA84084	Lost Lake/Knops Pond	B

 

1. Other water quality goals set by the community(e.g., protection of high-quality waters, in-lake phosphorus concentration goal to reduce recurrence of cyanobacteria blooms).

Table 3-4 shows the pollutant and associated water quality goals. For TP, there is no Nonnative Aquatic Plants TMDL for Lost Lake/Knops Pond (although there is a Mercury in Fish Tissue TMDL); therefore, we are using standards from the Gold Book as described in part b above.

Table 3-4: Water Quality Goals

Pollutant

Goal

Source

Total Phosphorus (TP)	Total phosphorus should not exceed: 50 µg/L in any stream 25 µg/L within any lake or reservoir	Quality Criteria for Water (USEPA 1986)
Bacteria	Class B Standards • Public Bathing Beaches: For E. coli, geometric mean of five most recent samples shall not exceed 126 colonies/100 ml and no single sample during the bathing season shall exceed 235 colonies/100 ml. For enterococci, geometric mean of five most recent samples shall not exceed 33 colonies/100 ml and no single sample during bathing season shall exceed 61 colonies/100 ml. • Other Waters and Nonbathing Season at Bathing Beaches: For E. coli, geometric mean of samples from most recent six months shall not exceed 126 colonies/100 ml (typically based on min. 5 samples) and no single sample shall exceed 235 colonies/100 ml. For enterococci, geometric mean of samples from most recent 6 months shall not exceed 33 colonies/100 ml, and no single sample shall exceed 61 colonies/100 ml.	Massachusetts Surface Water Quality Standards (314 CMR 4.00 2013)

Note: There may be more than one water quality goal for bacteria due to different Massachusetts Surface Water Quality Standards Classes for different Assessment Units within the watershed.

The section below summarizes the findings from the Water Quality Assessment Reports that relate to water quality and impairments. Select excerpts from these documents relating to the water quality in the watershed are included below. (Note that relevant information is included directly from these documents for informational purposes and has not been modified.)

Merrimack River Watershed 2004 Water Quality Assessment Report (MA84084 - Lost Lake/Knops Pond)

Four non-native aquatic plant species (Trapa natans, Myriophyllum spicatum, Cabomba caroliniana, Potamogeton crispus) have been reported in Lost Lake/Knops Pond. The Aquatic Life Use is assessed as impaired based on the presence of non-native aquatic plants. Cause(s) of Impairment: Non-Native Aquatic Plants, Eurasian Water Milfoil (Myriophyllum spicatum) Source(s) of Impairment: Introduction of Non-Native Organisms MassDEP DWM biologists collected fish from the pond in May 2004 and composite samples of edible fillets were analyzed for As, Cd, Hg, Pb, Se, PCBs and organochlorine pesticides. MA DPH has issued a fish consumption advisory due to mercury contamination for Lost Lake/Knops Pond. Children younger than 12 years of age, pregnant women, women of childbearing age who may become pregnant, and nursing mothers should not eat any Largemouth Bass fish from this water body. The public should limit consumption of Largemouth Bass fish to two meals per month. Cause(s) of Impairment: Mercury in Fish Tissue Source(s) of Impairment: Atmospheric Deposition - Toxics, Source Unknown Insufficient data were available to assess the Primary Contact Recreational Use. Insufficient data were available to assess the Secondary Contact Recreational Use. Insufficient data were available to assess the Aesthetics Use. Report Recommendations: Conduct monitoring to confirm the presence of non-native aquatic plants.

 

3.3 TMDL Pollutant Load Criteria

Due to the Mercury in Fish Tissue impairment, Lost Lake/Knops Pond is subject to a Regional Mercury TMDL, linked below.

• Northeast Regional Mercury Total Maximum Daily Load

The Lost Lake/Knops Pond watershed does not have a TMDL for non-native plants. MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for the Eurasian Water Milfoil (Myriophyllum spicatum) and Non-Native Aquatic Plants impairments as the impairments are nonpollutants (MassDEP 2019).

4.0       Water Quality Summary (Element A)

In addition to the water quality data discussed in Section 3, above, multiple studies have been conducted for Lost Lake/Knops Pond. Additionally, multiple methods to control invasive plant growth have been implemented, including those described in the 2012 Lost Lake/Knops Pond Resources Management Plan (GLA 2012) and the 2017 Aquatic Vegetation Management Program Annual Report for Lost Lake/Knops Pond (Solitude 2017). A detailed timeline of invasive aquatic plant control methods used is included in Section 6.  

4.1 Additional Water Quality Information

Additional water quality data and information collected from the Knops Pond/Lost Lake watershed from 1988 through 2017 is described below (ESS Group 2017, CEI, Inc. 2013, Baystate Environmental Engineers 1989, GLA 2014).

4.1.1 Lost Lake Watershed Management Plan (ESS Group, Inc. 2017)

This report describes pollutant and nutrient levels from natural and manmade sources in the Lost Lake/Knops Pond watershed. Results and conclusions from the report are summarized below:

• Sampling Locations. The sampling locations for TSS and point sources, other water quality parameters, and sediment are shown in Figure 4-1. The sampling locations for erosion (stormwater runoff) and point sources are shown in Figure 4-2. The groundwater seepage sampling locations are shown in Figure 4-3.
• Sampling Dates. Sampling was conducted on September 9, October 6, and November 16, 2016.
• Sediment Loading. Six locations were sampled for sediment loading (inlets, outlet, and three sites experiencing erosion), and the results are shown in Table 4-1. Parameters sampled included TSS, pH, specific conductance, salinity, temperature, dissolved oxygen (DO), and turbidity. The report found relatively high TSS levels at the locations experiencing erosion (170, 47, and 100 mg/L at TP-2, TP-3, and TP-4, respectively) compared to the low levels at the outlet (<5.0 milligrams per liter [mg/L]). These findings indicate that sediment settles in the lake and does not exit at the outlet. Additionally, the report states the low TSS values observed at the inlets to the lake (6 and <5.0 mg/L respectively for Inlet 1 and Inlet 2) indicated the sediment settles out before entering the lake.
• Dry Weather Sampling. Seven locations (inlets, outlet, and surface and bottom of both sides of Lost Lake/Knops Pond) were sampled for TP, dissolved phosphorus, nitrite-N, nitrate-N, total Kjeldahl nitrogen (TKN), total nitrogen, and TSS during dry weather. The results of this effort are shown in Table 4-2. The report indicated relatively high concentrations of phosphorus at the inlets (compared to the surface and bottom of Lost Lake/Knops Pond), suggesting large phosphorus sources from within the watershed. The report also stated that low DO concentrations indicated the presence of increased organics, decomposition, and algal growth and subsequent decay that may have been caused by excessive nutrients. The low DO concentrations can also create conditions that are favorable for release of sediment-bound phosphorus in the lake sediment, depending on how the phosphorus is bound.
• Water Profiles at Deepest Locations. Water profiles were collected at the deepest locations in Lost Lake/Knops Pond (Table 4-3). The report stated that water quality profiles indicate that water below 1.5 meters was not capable of supporting a healthy fish community in Lost Lake (the northern portions of Lost Lake/Knops Pond); however, the DO concentrations were suitable in Knops Pond (the southern portions of the waterbody).
• Wet Weather Sampling. The wet weather point source and erosion sampling (stormwater runoff at locations experiencing erosion) results from six stormwater samples are shown in Table 4-4. Water quality data includes TP, dissolved phosphorus, nitrate-N, TKN, flow, TSS, pH, specific conductivity, salinity, temperature, DO, and turbidity results at the inlets, outlet, and four locations experiencing erosion. The report stated that data from the roadway stormwater runoff indicated that shoreline erosion is occurring and that sediments containing nutrients are subsequently entering the lake. The high nutrient load in the sediments is indicated by the high phosphorus concentrations measured at the erosional sites. The report also stated the specific conductivity results indicated the sand and sediment are of more concern to water quality than road de-icing agents, although this may change seasonally.
• Groundwater Sampling. Lastly, groundwater nutrient concentrations and rate of seepage are shown in Table 4-5. The report stated that these results indicated that groundwater is entering the lake and that it may also contain nutrients, including dissolved phosphorus. Depending on the installation process of the seepage meters, the nutrients measured may be from the sediments rather than the groundwater itself.
• The measured TSS and concentrations of phosphorus at the sites experiencing erosion and inlets during sediment loading sampling, dry weather sampling, and wet weather sampling indicate that erosion, and specifically the associated phosphorus load, are a significant source of phosphorus to the lake and are most likely a contributor of nutrient issues and decreased water quality within the lake.

Figure 4-1: TSS and Point Source, Water Quality, and Sediment Sampling Locations (ESS, 2017).

 

Figure 4-2: Erosion and Point Source Sampling Locations (ESS 2017).

Figure 4-3: Groundwater Seepage Sampling Locations (ESS 2017).

 

 

Table 4-1: Sediment Loading Results from Samples Collected at Areas of Severe Erosion (ESS 2017).

Note: mg/L is milligrams per liter; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is part per trillion; C is degrees Celsius; % is percent; mg/L is milligrams per liter; NTU is nephelometric turbidity units.

Table 4-2: Dry Weather Water Quality Parameters (ESS 2017).

Note: SU is standard unit; NTU is nephelometric turbidity units; % is percent, mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius; CFS is cubic feet per second.

 

Table 4-3: Water Quality Profiles Collected at the Deepest Locations in Lost Lake and Knops Pond (ESS 2017).

 

Note: m is meters; % is percent; mg/L is milligrams per liter; μS/cm is microsiemens per centimeter; C is degrees Celsius.

 

Table 4-4: Wet Weather Sampling Results for Inlets and Erosional Sites (ESS 2017).

Note: mg/L is milligrams per liter, CFS is cubic feet per second; SU is standard unit; μS/cm is microsiemens per centimeter; ppt is parts per trillion; C is degrees Celsius; % is percent.

Table 4-5: Groundwater Nutrient Analysis (ESS 2017).

Note: mg/L is milligrams per liter; L/m²/day is liters per square meter per day.

4.1.2 Lost Lake Water Quality Investigation Report (CEI 2013)

Limited data was collected from the Deep Hole (deepest point) of Lost Lake in July, August, and September 2013 (1 to 2 samples per location). The Deep Hole sampling results are shown in Figure 4-5 (nitrate concentrations) and Figure 4-6 (nitrate + ammonia concentrations). Pore water sampling locations are shown in Figure 4-4. The pore water sampling results are shown in Figure 4-7 (phosphorus), Figure 4-8 (dissolved oxygen), and Figure 4-9 (chlorophyll-a).

The results for both Deep Hole and pore water sampling locations were compared to 1988/1989 water quality data (measured in the 1989 Diagnostic/Feasibility Study [Baystate Environmental Engineers 1989]). The 2013 report indicated that the data comparison results were inconclusive and that there was no trend in the data. Emerging contaminant data were collected as well; however, the report indicated the data results showed very low levels of several emerging contaminants and limited results associated with wastewater.

The report indicated that phosphorus sampling (shown in Figure 4-10 and Figure 4-11) showed the presence of wastewater, high levels of fertilizer, or other sources due to that fact that many of the phosphorus concentrations exceeded 20 parts per billion (ppb; a rough gauge of good water quality) and even 30 ppb (indicative of watershed issues, especially during a wet summer). However, bacteria were also found, which the report indicated showed the presence of untreated sewage from septic systems or livestock.

Figure 4-4: Sampling Locations (CEI 2013).

Figure 4-5: Pore Water Nitrate Concentrations (CEI 2013).

Figure 4-6: Pore Water Nitrate + Ammonia Concentrations (CEI 2013).

Figure 4-7: Deep Hole Phosphorus Levels (CEI 2013).

Note: ppb is parts per billion.

Figure 4-8: Deep Hole Dissolved Oxygen Levels (CEI 2013).

Note: ppm is parts per million.

Figure 4-9: Deep Hole Chlorophyll-a Levels (CEI 2003).

Note: ppm is parts per million.

Figure 4-10: Tributary, Piezometer, and Deep Hole Phosphorus and Precipitation (CEI 2003).

Figure 4-11: Tributary Phosphorus Levels (CEI 2013).

4.1.3 A Diagnostic / Feasibility Study for the Management of Lost Lake / Knopp’s [sic] Pond (Baystate Environmental Engineers 1989)

This report detailed historic water quality conditions in Lost Lake/Knops Pond and identified the major sources of nutrient loadings in 1989, which may or may not reflect current conditions. The report findings are summarized below:

• Sampling Locations. Figure 4-12 shows water quality sampling locations KP-1 (inlet from unnamed tributary), KP-2 (inlet from Martins Pond Brook), and KP-3 through KP-7 (distributed throughout Lost Lake/ Knops Pond).
• Sampling Results. Water quality sampling results are shown in Table 4-6. The study indicated that results suggested Martin’s Pond Brook was a major source of phosphorus loading and that the phosphorus remineralization under anoxic bottom conditions was not an important source to the lake. The study indicated the orthophosphate data results indicate that the pond is mesotrophic. Ammonia levels were highest during the winter and late fall, which according to the study indicated that organic material was decomposing.
• Tributary Sampling Results. Tributary water quality data was shown in Table 4-7. The results indicated that the Gibbet Hill tributary was an important source of nitrogen and phosphorus and may have led to the high nutrient levels in Martin’s Pond Brook. Additionally, the report indicated that the high density of residences near the lake was a potential source of nutrients.
• Well Water Sampling Results. The well water quality data are shown in Table 4-8. The study indicated that bacteria sampling results showed that septic systems were not responsible for the bacteria counts. It also indicated that bacteria counts were most likely due to wildlife, based on the fecal coliform (FC) to fecal streptococci (FS) ratios.
• Nutrient Loading. Additionally, the study calculated nutrients loads based on sampling data and typical export coefficients for sources in Lost Lake/Knops Pond, including the Unnamed Tributary, Martin’s Pond Brook, “Redwater” (shown in Figure 4-12), groundwater (direct input), atmospheric deposition (direct input), bird inputs (direct input), and internal load (anoxic loading). The results of this nutrient load table (shown in Table 4-9) indicated that approximately 63% of the phosphorus load and 51% of the nitrogen load were from the two inlets.
• Overall, the study indicated most of the phosphorus loading (approximately 63%) was from the two inlets, with most from the inlet to Martins Pond Brook. These results concur with the conclusions from the 2013 and 2017 study, which both identify phosphorus as a nutrient of concern within the watershed, although the 2017 study specifically identifies erosion as a major source.

Figure 4-12: Sampling Stations (Baystate Environmental Engineers 1989).

 

 

Table 4-6: Water Quality Data (Baystate Environmental Engineers 1989).

 

Table 4-7: Tributary Water Quality Data (Baystate Environmental Engineers, 1989).

 

Table 4-8: Well Water Quality Data (Baystate Environmental Engineers 1989).

 

 

 

Table 4-9: Nutrient Loads to Lost Lake/Knops Pond (Baystate Environmental Engineers 1989).

 

 

4.1.4 Erosion & Storm Water Runoff at Lost Lake/Knops Pond 2014 Presentation (GLA 2014)

This presentation by GLA on the topic of erosion and stormwater runoff included photos and locations with moderate to severe erosion due to stormwater runoff. Photos from the presentation are shown in Figure 4-13. The following roads and locations were shown:

·         Alder Road	·         Moose Trail
·         Baby Beach	·         Off Prescott Street
·         Birchwood Avenue	·         Paul Revere Trail and Boat Launch
·         Boathouse Road	·         Point Road
·         Highland Road	·         Radio Road
·         Intersection of Pine and Paul Revere Trails	·         Redskin Trail
·         Island Road and Island Road Bridge	·         Shelters Road
·         Juniper Point	·         Summit Avenue
·         Lost Lake Drive at Outlet	·         Wenuchias Trail
·         Maplewood Avenue	·         Weymisset Road

 

Figure 4-13: Photos from GLA Presentation (GLA 2014).

From left to right: Boathouse Road, Paul Revere Trail off Pine Trail (Lost Lake Boat Launch), and Alder Road.

5.0       Water Quality Goals for Lost Lake and Knops Pond (Element B)

Water quality goals are a critical component of watershed management plans; they are the “yardstick” by which management success is measured. The water quality goals describe the pollutant load reductions that indicate improvement in the lake’s water quality. The establishment of water quality goals for Lost Lake/Knops Pond was guided by an analysis of water quality data, nutrient load modeling using the WBP tool, and with input from GPAC and GLA.  

5.1 Estimated Pollutant Loads

GIS was used for the pollutant loading analysis. The land-use data (MassGIS 2009b) was intersected with impervious cover data (MassGIS 2009a) and USDA Natural Resources Conservation Service (NRCS) soils data (USDA NRCS, MassGIS 2012) to create a combined land use/land cover grid. The grid was used to sum the total area of each unique land use/land cover type.

The amount of DCIA was estimated using the Sutherland equations as described above, and any reduction in impervious area due to disconnection (i.e., the area difference between TIA and DCIA) was assigned to the pervious D soil category for that land use to simulate that some infiltration will likely occur after runoff from disconnected impervious surfaces passes over pervious surfaces.

Pollutant loading for key nonpoint source pollutants in the watershed was estimated by multiplying each land use/cover type area by its pollutant load export rate (PLER). The PLERs are an estimate of the annual total pollutant load exported via stormwater from a given unit area of a particular land cover type. The PLER values for TN, TP, and TSS were obtained from USEPA (Voorhees 2016b; see documentation provided in Appendix A) as follows:

L_n = A_n * P_n

Where L_n = Loading of land use/cover type n in pounds per year (lbs./yr.); A_n = area of land use/cover type n (acres); P_n = pollutant load export rate of land use/cover type n in pounds per acre per year (lbs./acre/yr.).

Table 5-1 presents the estimated land-use based TP, TN, and TSS within the Lost Lake/Knops Pond watershed. The largest contributor of land-use based TP, TN, and TSS load originates from areas designated as forested. TP and TN generated from forested areas is generally a result of natural processes such as decomposition of leaf litter and other organic material; the forested portions of the watershed therefore are unlikely to provide opportunities for nutrient load reductions through BMPs. Low density residential areas (including roads) are the second largest contributors of land-use based TP, TN, and TSS load in the watershed. Residential areas provide excellent opportunities for nutrient load reductions through BMPs, as described in the following sections.

Table 5-1: Estimated Pollutant Loading for Key Nonpoint Source Pollutants.

Land Use Type	Pollutant Loading1
	TP (lbs./yr.)	TN (lbs./yr.)	TSS (tons/yr.)

TOTAL	557	3,659	92.13
Forest	299	1,580	61.99
Low Density Residential	87	871	11.96
Agriculture	99	595	8.19
Open Land	27	269	5.18
High Density Residential	23	158	2.34
Commercial	12	109	1.36
Medium Density Residential	9	72	1.04
Industrial	1	6	0.07
Highway	0	0	0.00
1These estimates do not consider loads from point sources or septic systems. Note: TP is total phosphorus; TN is total Nitrogen; TSS is total suspended solids; and lbs./yr. is pounds per year.

 

It is important to note that pollutant loads presented in Table 5-1 do not consider loads from point sources or septic systems. In the Lost Lake/Knops Pond watershed, septic systems have been identified as a potential source of pollutant loading since they are used throughout the watershed. Septic system sources should be separately evaluated to determine whether septic system upgrades or sanitary sewer system conversion would cost-effectively reduce bacteria and nutrient sources in the watershed.

5.2 Water Quality Goals

Many methodologies can be used to set pollutant load reduction goals for a WBP. Goals can be based on water quality criteria, surface water standards, existing monitoring data, existing TMDL criteria, or other data. As discussed in Element A, water quality goals for this WBP are focused on reducing nutrient (TP and TN) and sediment (TSS) loads to Lost Lake/Knops Pond. The water quality goals, and corresponding required loading reductions are included in Table 5-2.

Water quality goals for primary NPS pollutants are listed in Table 5-2 based on the following:

• TMDL water quality goals are used if a TMDL exists for the water body.
• For all water bodies, including impaired waters with a pathogen TMDL, the water quality goal for bacteria is based on theMassachusetts Surface Water Quality Standards (314 CMR 4.00 2013) that apply to the Water Class of the selected water body.
• If the water body does not have a TMDL for TP, a default target TP concentration is provided which is based on guidance provided in the Gold Book. Because there are no similar default water quality goals for TN and TSS, goals for these pollutants are provided in Table 5-2 only if a TMDL exists or alternate goal(s) have been optionally established by the WBP author.
• According to the Gold Book, total phosphorus should not exceed 50 µg/L in any stream at the point where it enters any lake or reservoir. The water quality loading goal was estimated by multiplying this target maximum phosphorus concentration (50 µg/L) by the estimated annual watershed discharge for the selected water body. To estimate the annual watershed discharge, the mean flow was used, which was estimated based on United States Geological Survey (USGS) “Runoff Depth” estimates for Massachusetts (Cohen and Randall 1998). This document provides statewide estimates of annual Precipitation (P), Evapotranspiration (ET), and Runoff depths ® for the northeastern United States. According to their method, R is defined as all water reaching a discharge point (including surface and groundwater) and is calculated by:

P – ET = R

A mean R was determined for the watershed by calculating the average value of R within the watershed boundary. This method includes the following assumptions/limitations:

1. For lakes and ponds, the estimate of annual TP loading is averaged across the entire watershed. However, a given lake or reservoir may have multiple tributary streams, and each stream may drain land with vastly different characteristics. For example, one tributary may drain a highly developed residential area, while a second tributary may drain primarily forested and undeveloped land. In this case, one tributary may exhibit much higher phosphorus concentrations than the average of all streams in the selected watershed.
2. The estimated existing loading value only accounts for phosphorus due to stormwater runoff. Other sources of phosphorus may be relevant, particularly phosphorus from on-site wastewater treatment (septic systems) close to receiving waters. Phosphorus does not typically travel far within an aquifer, but in watersheds that are primarily unsewered, septic systems and other similar groundwater-related sources may contribute a significant load of phosphorus that is not captured in this analysis. As such, it is important to consider the estimated TP loading as “the expected TP loading from stormwater sources.”
3. If the calculated water quality goal is higher than the existing estimated total load, the water quality goal is automatically set equal to the existing estimated total load.

The WBP tool calculates an estimated TP load of 557 lbs./yr. and a water quality goal of 557 lbs./yr. of TP. This would mean that the required load reduction is 0 lbs./yr. to meet the water quality goal. However, the estimated pollutant load and water quality goal do not account for nutrient load from the observed erosion (the soil may be nutrient-rich due to historical agricultural use), septic systems, waterfowl, atmospheric, and/or internal load. The pollutant load also does not account for current land use (e.g., recent development) as the model uses an older land use dataset (2016). Furthermore, observations of roadway erosion and eutrophication throughout the watershed during the site visit indicate that a reduction in nutrient load is required to improve water quality in Lost Lake/Knops Pond.

Therefore, a load reduction of 10% of the existing estimated total load of TP, TN, and TSS is proposed as the required load reduction. Modifications to the required load reduction would be made based on the results of the water quality monitoring program.  

The following adaptive sequence is recommended to sequentially track and meet these load reduction goals:

1. Establish a short-term reduction goal to reduce land-use-based TP, TN, and TSS by 10%. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons per year (tons/yr.) for TP, TN, and TSS, respectively.
2. Implement a baseline water quality monitoring program in accordance with Element I. Results from the monitoring program should advise if Element C BMPs have been effective at addressing listed water quality impairments or water quality goals. Results can further be used to create, periodically inform, or adjust load reduction goals.
3. Establish a long-term reduction goal to reduce land-use-based TP, TN, and TSS over the next 15 years based on monitoring data.

Table 5-2: Pollutant Load Reductions Needed.

Pollutant	Existing Estimated Total Load	Water Quality Target	Required Load Reduction for short-term goal (10%)
Total Phosphorus	557 lbs./yr.	501 lbs./yr.	56 lbs./yr.
Total Nitrogen	3,659 lbs./yr.	3,293 lbs./yr.	366 lbs./yr.
Total Suspended Solids	92 tons/yr.	83 tons/yr.	9 tons/yr.

Note: lbs./yr. is pounds per year.

The proposed BMPs described in this WBP are expected to reduce TP, TN, and TSS loads to Lost Lake/Knops Pond; however, additional BMP implementation/load reduction may be required to meet the water quality goals.

 

6.0       Management Actions to Control Phosphorus (Elements C, D, and E)

The proposed management measures were determined using an iterative process. First, the hotspot map was reviewed, and potential sites located on Town-owned parcels were selected. Next, the field investigation was conducted to assess whether the selected sites are suitable for BMPs and to determine the BMP that best fit site characteristics (e.g., topography, soil type, area). Areas not initially selected were added to the list of potential sites if the area was determined to be suitable for a BMP during the site investigation. After the site investigation, a desktop review was conducted to determine the siting of the BMPs, and the estimated nutrient load reduction based on drainage area and land use. The proposed BMPs were presented to members of the GLA and GPAC during the stakeholder meeting on October 21, 2021. The final proposed BMPs were selected based on feedback from the stakeholder meeting.

Nutrient load reductions for the proposed BMPs were determined using the WBP tool with drainage areas and land use calculated in GIS. The WBP tool also calculates the estimated BMP footprint. The cost estimates for the site-specific BMPs were determined using the initial baseline provided by the WBP tool and adding 30% for design costs, 10% for permitting costs, 10% for project management costs, and 15% for contingency. A 50% contingency was added to represent the maturity level based on the Association for the Advancement of Cost Engineering (AACE) Level 4 cost estimate.

There are two main types of proposed management measures: (1) watershed-wide BMPs that are recommended for implementation throughout the watershed in addition to the key locations specified in this WBP and (2) site-specific BMPs that are recommended for a specific location in the watershed. The proposed management measures are all structural BMPs, except for catch basin cleaning which is a nonstructural or programmatic BMP. Figure 6-1, below, shows the proposed BMP locations.

 

Figure 6-1: Proposed BMP Locations.

6.1 BMP Hotspot Map

BMPs are management measures, activities, and maintenance procedures that prevent or reduce nonpoint source or point source pollution to achieve water quality goals. Examples of BMPs include rain gardens, vegetated swales, and catch basin maintenance. The following points describe the GIS-based analysis conducted within the watershed to identify high priority parcels for BMP implementation:

• Each parcel within the watershed was evaluated based on ten criteria accounting for the parcel ownership, social value, and implementation feasibility (See Table 6-1 for more detail below).
• Each criterion was then given a score from 0 to 5 to represent the priority for BMP implementation based on a metric corresponding to the criterion. (A score of 0 would represent lowest priority for BMP implementation whereas a score of 5 would represent highest priority for BMP implementation.)
• A multiplier was also assigned to each criterion, which reflected the weighted importance of the criterion. (A criterion with a multiplier of 3 had greater weight on the overall prioritization of the parcel than a criterion with a multiplier of 1.)
• The weighted scores for the criteria were then summed for each parcel to calculate a total BMP priority score.

Table 6-1 presents the criteria, indicator type, metrics, scores, and multipliers for this analysis. Parcels with total scores above 60 are recommended for further investigation for BMP implementation suitability.

Figure 6-2 presents the resulting BMP Hotspot Map for the watershed. The following link includes a Microsoft Excel file with information for parcels with a score above 60: hotspot spreadsheet. These parcels are spread out within the watershed and generally are not directly adjacent to Lost Lake/Knops Pond, except for the forested parcels to the northwest of the lake. Additionally, the lack of suitable parcels adjacent to the watershed suggests that proposed BMPs may need to be implemented either in the roadway right-of-way or on smaller parcels of public land, and/or that multiple BMPs may be needed to significantly improve the water quality in the lake. Because several parcels in the northwest portion of the watershed with known current and historic agricultural activities are on the BMP Hotspot map, if monitoring results indicate that agricultural activities are contributing excessive nutrient load to the watershed, BMPs may be implemented in this area.

This analysis solely evaluated individual parcels for BMP implementation suitability and likelihood for the measures to perform effectively within the parcel’s features. This analysis does not quantify the pollutant loading to these parcels from the parcel’s upstream catchment. When further evaluating a parcel’s BMP implementation suitability and cost-effectiveness of BMP implementation, the existing pollutant loading from the parcel’s upstream catchment and potential pollutant load reduction from BMP implementation should be evaluated.

GIS data used for the BMP Hotspot Map analysis included:

• MassGIS (2015a);
• MassGIS (2015b);
• MassGIS (2017a);
• MassGIS (2017b);
• MassGIS (2020);
• Massachusetts Department of Revenue Division of Local Services (2016);
• MassGIS (2005);
• ArcGIS (2020);
• MassGIS (2009b);
• MassGIS (2012); and
• ArcGIS (2020b).

Table 6-1: Matrix for BMP Hotspot Map GIS-Based Analysis.

 

Figure 6-2: BMP Hotspot Map[8]

Ctrl + Click on the map to view a full-sized image in your web browser

6.2 Field Watershed Investigation

Geosyntec conducted a field investigation in the Lost Lake/Knops Pond watershed on August 30, 2021 to identify and confirm sources of pollution and to identify potential BMPs that can be implemented to reduce the pollutant load to Lost Lake/Knops Pond.

Findings from the site visit are described below:

• Birchwood Avenue/Hazelwood Avenue and the “Inlet 2” north of Birchwood Avenue. At this location, erosion was observed along roads and in residential driveways. Here, the stream is small and slow-moving (approximately 3 feet wide with approximately 1-inch-deep flowing water). An observed catch basin on Birchwood Avenue was partially covered with concrete and filled with sediment.
• Off Prescott Road. Here, a dirt road appeared to have been recently regraded.
• Grotonwood Camp At this location, a large parking lot, untreated stormwater runoff appears to concentrate east of the building and discharge into the woods where there was visible erosion. The opportunity exists to implement a stormwater BMP here; this location also has public education and outreach potential. A French drain is also located in this location, which appears to have been more recently installed and collects roof runoff and discharges into the wooded area.
• Martins Pond Brook crossing (culvert) at Martins Pond Road. At this location, catch basin full of sediment was observed.
• Shattuck Street. Here, Martins Pond Road, a dirt road, appears to be contributing sediment to the downstream paved road, where the sediment is entering the catch basins.
• Scarlet Hill Farm (horse farm). Here, the Project Team walked along a portion of the horse farm from Shattuck Street where it abuts Martins Pond Brook; they did not see any evidence of horses having access to the brook.
• Met with John Smigelski at 150 Mill St (Excalibur Farm). John Smigelski showed the Project Team soil sampling data (2011 and earlier years) from his fields off of Groton School Road, which are not within the watershed. The samples indicated elevated levels of TP in the topsoil. John noted that he does not add phosphorus to his soils since the levels are high.
• Lowell Road. Here, it appears that stormwater runoff from Gibbet Hill Grill (restaurant and grazing land) as well as Lawrence Academy discharges to a stormwater pond south of Lowell Road.
• Martin’s Pond Brook crossing (culvert) at Lowell Road. The brook is very slow moving here, and banks are densely vegetated.
• Lost Lake Drive. Here, Martin’s Pond Brook flows through large wetland area. Catch basins along Lost Lake Drive appear to discharge to the wetland.
• Fire Station on Lost Lake Drive. Catch basin with visible sediment buildup on pavement nearby was observed in the driveway; there is the potential for BMP implementation here, though the Project Team suspects that the drainage area is not very large.
• Tavern Road. Erosion was observed on both sides of road; Martins Pond Brook (“Inlet 1”) discharges into the pond east of Tavern Road.
• Boat House Road. Erosion was observed on both sides of road.
• Observed outlet of watershed (beginning of Cow Pond Brook).
• Boat Launch/Fisherman access off of Pine Trail. Erosion and sedimentation were observed in the parking area, as was evidence of sediment loading from Pine Trail down the steep entrance to the parking area. An opportunity to implement a BMP exists at this location. The wetland and pond adjacent to the parking area was stagnant and showed signs of eutrophication
• Highland Road, Radio Road, Weymisset Road, and Island Road. Numerous areas along road and residential driveways with erosion were observed.

Algal blooms, an indication of eutrophication, were present in the ponds that were visited. Locations include off of Radio Road, Tavern Road, the Lost Lake Boat Launch (Pine Trail), and across from Gibbet Hill Grill. These ponds are located throughout the watershed and demonstrate evidence of excessive nutrients.

Erosion on the sides and slopes of paved roads was present throughout the watershed. Loss of vegetation was also noted. The erosion was especially pronounced and of concern on the “esker” roads, located directly adjacent to Lost Lake/Knops Pond. In many cases, this erosion also presented road stability concerns, as road foundations were eroding into the lake. Figure 6-3, below, shows examples of erosion in the watershed.

Figure 6-3: Erosion off Paved Roads.

From left to right, erosion on Island Road, Radio Road, and Pine Trail.

Gullying and channelization were observed on Radio Road and Pine Trail. On the slope of Radio Road, evidence of stormwater runoff flowing directly into Lost Lake/Knops Pond was observed. Loss of vegetation was observed on Island Road and Pine Tail.

Erosion was present on unpaved roads throughout the watershed. Additionally, evidence of regrading (parked equipment and fresh soil) of dirt roads was found on Off Prescott Street. Figure 6-4 shows examples of erosion on unpaved roads.

Figure 6-4: Erosion on Unpaved Roads.

From left to right, erosion on Off Prescott Street, Birchwood Ave, and Shattuck Street.

Gullying and channelization were observed on Birchwood Avenue and Shattuck Street.

Maintenance needs were also observed at several locations during the field investigation. Sediment was found in catch basins at the intersection of Chester Hill and Martins Pond Road, and there are likely other catch basins in the watershed that require cleaning. Additionally, a catch basin on Maplewood Avenue was partially covered by concrete tiles and filled with sediment.

In addition to the field investigation, the Project Team also contacted large land users in the watershed about their land management practices. The findings from the conversations are summarized below:

• Scarlet Hill Farm. This horse farm has a public trail easement. No significant erosion or other sources of nutrients were observed during the site visit. A stream runs adjacent to the public trail.
• Gibbet Hill/Weber Restaurant Group. There are two main land uses on this property: a leased-out 100% organic vegetable farm and a Black Angus cattle farm with 100 acres for grazing, a 2.5-acre field, ½-acre for lamb pasture and ¼-acre for pigs. There is no irrigation.
• Grotonwood Camp. No fertilizer is used at this property. There is an infiltration system for roof drains and no other constructure stormwater management. This land user expressed interest in future partnering on projects.
• Groton Country Club. A phosphorus free fertilizer is applied to the putting greens once a year and to the fairways in the spring. The fertilizer is not applied on open areas or roughs.
• Lawrence Academy. No information was provided. No significant sources of erosion or other sources of nutrients were identified from the road adjacent to the site.
• Excalibur Farm. Although Excalibur Farm is located outside of the watershed, geological and soil attributes at the farm may be like those within the watershed. Soil tests indicate high phosphorus concentrations, although the source may be from the historical agricultural use, soil properties, or other sources.
• Department of Public Works for Town of Groton. Both salt and sand are used on roads within the watershed and on roads directly adjacent to the watershed. The application varies based on the type of storm: for icy storm, sand is used and for storms with less ice, only salt is used. Calcium chloride is often used with the salt. Typically, the roads adjacent to Lost Lake/Knops Pond are salted/sanded once per storm. The applicator machines are calibrated to use the minimum amount of salt and sand needed to provide deicing.

6.3 Existing Management Measures

Existing management measures in Lost Lake/Knops Pond mostly consist of in-lake treatments to control invasive plants. The following timeline show the progression of herbicide treatments:

• 2002: Herbicidal treatment of the entire lake for the control of milfoil was successful in reducing weed growth (GLA 2012).
  • 2003–2004: Spot treatments were conducted to control regrowth (GLA 2012).
• 2003–2011: Limited work was conducted. A weed harvester operated by GLA was used to control new growth (GLA 2012).
• 2011: GLA hired Aquatic Control Technology to conduct a biological survey and propose management alternatives (GLA 2012).
• 2011–2012: GLA continued use of the weed harvester; weed regrowth, specifically of milfoil and Cabomba was intense due to warmer than typical weather (GLA 2012).
• 2017: Herbicide treatment was applied by Solitude Lake Management and focused on areas of dense milfoil, curlyleaf pondweed, and fanwort growth that were identified during a pretreatment survey. Reward (diquot) and Clipper (flumioxazin) were applied to 74 acres (Solitude 2017).
  • Water quality samples were collected, and blue/green cell counts were found to be 540 cells per milliliter (cells/mL), below the Massachusetts Department of Public Health contact threshold of 70,000 cells/mL (Solitude 2017).

Overall, there has been limited success in controlling the invasive plant population in the lake. It should be noted that the algal blooms prevent aquatic plants from growing. If the algal blooms are reduced and the water clarify improves, it is expected that the aquatic plant growth will increase substantially.  

6.4 Watershed-Wide BMPs

The major source of pollution, as determined in past studies and through observations during site investigation, is erosion from unpaved roads and from the slopes of paved roads. Erosion was observed throughout the watershed but is of particular concern around the lake on the “esker” roads. This erosion is both a water quality and safety issue, as the sediment is flowing directly into the lake, carrying nutrients with no attenuation from overland flow, and is eroding from under the road, causing concern regarding the structural integrity of the roads. As such, the watershed-wide BMPs that address erosion (e.g., slope stabilization and dirt road BMPs) should be prioritized. Erosion is also causing many catch basins throughout the watershed to be filled with sediment.

The following watershed-wide BMPs are proposed:

• Slope Stabilization off of Paved Roads. As discussed in the site visit summary, there is severe erosion at many of the paved roads throughout the watershed, especially at the “esker” roads directly adjacent to Lost Lake/Knops Pond. Roads in need of slope stabilization observed during the site visit include Island Road, Radio Road, Weymisset Road, Moose Trail, and Boat House Road, although there may be additional locations for slope stabilization within the watershed. There are several potential methods of slope stabilization, including reseeding with native plants and installing fabric filters (such as jute or geotextiles). While reseeding, it is important to be mindful of limiting fertilizer use, to avoid additional nutrient loading. There are three main components to the slope stabilization: topsoil, hydroseeding (including fertilizer), and an optional erosion control blanket. A cost estimate is shown in Table 6-2.

Table 6-2: Slope Stabilization Cost Estimates

Approximate Site Area (square feet)

Topsoil & Seeding

Topsoil, Seeding, & Erosion Control Blanket

	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)	Total Cost (-30% to +50%)	Cost Per Square Foot (-30% to +50%)
500	$1,200 ($840 to $1,800)	$2.40  ($1.68 to $3.60)	$2,200  ($1,540 to $3,300)	$4.50 ($3.15 to $6.75)
2,000	$4,800  ($3,360 to $7,200)	$2.40 ($1.68 to $3.60)	$9,000  ($6,300 to $13,500)	$4.50 ($3.15 to $6.75)
10,000	$23,800  ($16,660 to $35,700)	$2.40  ($1.68 to $3.60)	$44,900  ($31,430 to $67,350)	$4.50 ($3.15 to $6.75)
50,000	$119,000 ($83,300 to $178,500)	$2.40  ($1.68 to $3.60)	$224,500 ($157,150 to $336,750)	$4.50  ($3.15 to $6.75)

• Dirt Road BMPs. Many of the dirt roads throughout the watershed showed signs of moderate to severe erosion, including Maplewood Avenue, Birchwood Avenue, Off Prescott Street, and Shattuck Street. The Massachusetts Unpaved Roads BMP Manual (MassDEP 2011) includes a variety of potential dirt road BMPs. Proposed solutions to dirt road erosion include maintaining natural buffers and drainage ways, general shoulder maintenance, and structural measures such as regrading roads, installing waterbars, and lining ditches. Figure 6-5 shows an example of two types of ditches.

 

Figure 6-5: Typical Ditch Detail (MassDEP 2011)

We recommend that GLA and GPAC coordinate with the Town of Groton on any dirt road-related projects or grant proposals.

• Catch Basin Maintenance and Structural BMPs. As described in the site visit summary, many catch basins throughout the watershed were filled with sediment due to erosion, including catch basins located on Maplewood Avenue, Shattuck Street, and Prescott Street. The catch basins should be cleaned in coordination with the Town of Groton. Stabilizing the dirt roads and slopes can help reduce erosion; however, in addition, small collection sumps and/or rain gardens can be installed upstream of drain inlets. The catch basin on Maplewood Avenue was filled with sediment and partially covered with concrete tiles. This catch basin should either be fully covered to prevent sediment from entering the sump and subsequently the drainpipes that discharge to Lost Lake/Knops Pond or opened to receive stormwater runoff. Modifications can also be made to the catch basin inlet and sump to better capture sediment to prevent discharge into the lake or its tributaries. Figure 6-6 shows an example of a catch basin filtration inlet system that removes sediment and oil from stormwater runoff (New Pig 2021).

 

Figure 6-6: Catch Basin Filtration Inlet System (New Pig 2021)

6.5 Site-Specific BMPs

We also identified several site-specific proposed management measures as opportunities to capture and slow runoff and reduce pollutant loading. The six site-specific BMPs are the Grotonwood Camp raingarden, the Boat Launch raingarden, the Boat Launch swale, the Birchwood Road swale, the Shattuck Street lot raingarden, and the Shattuck Street swale. The conceptual design sheets for the proposed BMPs are included as Appendix B. The site-specific BMPs should be implemented in conjunction with the site-specific BMPs, as it is unlikely that the site-specific BMPs alone will provide enough nutrient load removal to resolve the water quality issues within the watershed. The site-specific BMPs are described in more detail below:

• Grotonwood Camp Raingarden. The proposed raingarden will infiltrate stormwater runoff from the Grotonwood Camp main parking lot, a relatively large area of impervious surface for the watershed. Currently, there are signs of erosion at the edge of the forest where the stormwater runoff channelizes from the parking lot. The proposed raingarden would mitigate this erosion and provide stormwater quantity and quality benefits, such as reducing peak flows from the parking lot and reducing the nutrient and sediment load. Although the stormwater runoff does not discharge directly to a tributary or Lost Lake/Knops Pond, it discharges approximately 100 feet from a stream that runs through Grotonwood Camp.
• Boat Launch Raingarden. The proposed boat launch raingarden at the Lost Lake Public Boat Launch will infiltrate stormwater runoff from the boat launch parking lot, which is mostly paved. The Boat Launch Swale, described below, will treat stormwater runoff from the paved road (off Pine Trail) that leads down to the parking lot. Currently, there is significant erosion at the boat launch. Additionally, there is eutrophication in the pond directly adjacent to the boat launch, indicating excessive nutrient loads. Installing a raingarden at the boat launch would infiltrate stormwater runoff, reducing erosion, and mitigate the nutrient load that enters the lake directly.
• Boat Launch Swale. The proposed boat launch swale will work in conjunction with the raingarden described above. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loads from the road leading to the boat launch. The road is paved and moderately steep and there are signs of erosion on either side of it. As the stormwater runoff is already directed towards the sides of the road, installing a swale will provide water quality treatment instead of carrying nutrients and sediment towards the boat launch and subsequently to Lost Lake/Knops Pond, as is currently occurring due to channelized flow.
• Birchwood Avenue Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff and reduce nutrient loading from Birchwood Road. Birchwood Avenue is a paved, steep, winding road with observed erosion at the outer edge where the road curves. The erosion is severe, with defined channels and gullies on the slope of the road. Stormwater runoff from Birchwood Avenue flows into the Unnamed Tributary that leads directly into Lost Lake/ Knops Pond.
• Shattuck Street Lot Raingarden. The proposed Shattuck Street Lot raingarden will infiltrate stormwater runoff from Shattuck Street and part of Scarlet Hill Farm. The proposed location is the parking lot for the public access trails at Scarlet Hill Farm that run adjacent to a stream that is a tributary for Lost Lake/Knops Pond. Although Scarlet Hill Farm has received awards for their manure practices, agricultural land tends to have higher pollutant loads than forested or open land.
• Shattuck Street Swale. The proposed treatment/water quality swale will infiltrate stormwater runoff from Shattuck Street and the surrounding area and mitigate the nutrient loads. Like the Shattuck Street Lot raingarden, the drainage area for the swale also includes agricultural land at Scarlet Hill Farm. In addition, there is severe erosion on Shattuck Street, which is unpaved (gravel) with a moderately steep slope; therefore, installing the swale would reduce the erosion by reducing stormwater runoff and mitigate the associated nutrient load.

More information about the construction and operation and maintenance (O&M) of each type is included below.

Raingardens/Bioretention Areas (MassDEP 2016a):

• Raingardens use soil, plants, and microbes to treat stormwater before it infiltrates into the soil or is discharged. They can provide pollutant removal and infiltrate up to 1 inch of rainfall, in addition to providing groundwater recharge.
• Raingardens are comprised of shallow depressions with a layer of sandy soil, mulch, and planted with dense vegetation. Generally, they are designed to pond to a depth of water 6 to 8 inches deep. The soil mix should be sandy loam or loamy sand with a clay content of less than 15%.
• Soil and any eroded areas should be inspected monthly, and litter and debris should be removed accordingly. Invasive species should be removed as needed and mulch replaced every two years. With proper selection of plants, the need for fertilizers and pesticides should be eliminated or at least very minimal. This is especially important for the Lost Lake/Knops Pond watershed, as introducing additional nutrient loads would be detrimental to water quality and negate the use of the raingarden.

Treatment Swales (MassDEP 2016a):

• Water quality or treatment swales are vegetated open channels that convey runoff and treat the stormwater runoff.
• Soil characteristics, flow capacity, erosion resistance, and vegetation should be considered when designing a treatment swale.
• Swale maintenance includes inspecting swales to ensure vegetation health and lack of erosion (once per month initially, then twice per year); mow if necessary (as needed); remove sediment and debris manually (at least once per year), and re-seed as necessary).

6.6 Non-Structural BMPs and Watershed Outreach (Category 5)

Non-structural BMPs typically do not involve construction and are often more broadly applied throughout a watershed. Implementation of these BMPs can result in significant load reductions. Examples of non-structural BMPs include:

• Municipal “good housekeeping” practices such as street sweeping and leaf litter collection programs can reduce phosphorus loading by reducing transport of pollutants through stormwater systems.
• Regulations can be used to help affect behavior change and manage land uses practices; examples of regulatory tools include stormwater management regulations, septic system ordinances, fertilizer regulations, pet waste removal requirements, and more.
• Outreach and education can also be used to help change behavior and reduce pollutant loading by encouraging and promoting activities that reduce or prevent pollutant loading such as fertilizer reduction incentives, pet waste pick-up programs, pond-friendly landscaping workshops and more.
• Land conservation is a common tool that can be used to prevent loading from land conversion activities.

Table 6-3 summarizes potential non-structural BMPs that can be implemented throughout the watershed.

Table 6-3: Non-Structural BMPs

Non-Structural BMP	Description	Responsible Party
Fertilizer Program	Reduce the amount and frequency of fertilizer application[9] to pervious developed areas throughout the watershed.	Town of Groton; GPAC; GLA
Street Sweeping	Optimize street sweeping locations and frequency equivalent to two times a year sweeping (in Spring and Fall) of 50% of roads within 650-feet of the shoreline, using vacuum assisted sweeper.	Town of Groton
Leaf Litter Management	Provide leaf collection at least 4 times during October and November for properties within 650-feet of the shoreline. Within 24 hours of leaf collection, collect remaining leaf litter on paved streets using a cleaning machine, such as a mechanical broom or vacuum assisted street cleaner.	Town of Groton
Shoreline Buffer	Retrofit developed areas along shoreline with 20-ft-no-mow/no-alteration grassed buffer for properties within 425-feet of the shoreline.	Town of Groton
Regulations	Establish municipal regulations to enable and promote improved stormwater management, buffer protections, and shoreland controls.	Town Planning Staff
Land Conservation	Coordinate with groups to prioritize land conservation goals/target parcels to reduce future load associated with new development.	Town Planning Staff; GPAC; GLA
Impervious Disconnection	Direct runoff from impervious areas such as roadways, parking lots, and roofs, and discharge it to adjacent vegetated permeable surfaces that are of sufficient size with adequate soils to receive the runoff without causing negative impacts to adjacent down-gradient properties.	Town of Groton

Watershed outreach will take place through educational kiosks at the proposed raingardens. These kiosks will include information on water quality in Lost Lake/Knops Pond, the purpose of the stormwater BMPs and their impact on water quality, and actions residents can take to improve water quality in the watershed.

The target audiences include residents in the watershed, recreational users of Lost Lake/Knops Pond (boaters, beach-goers, etc.), and watershed organizations and other user groups (GLA, GPAC, etc.)

GLA and/or GPAC may coordinate with the Town of Groton on distribution of educational materials such as lawn and landscaping education, pet waste management, car washing, and other topics. GLA and/or GPAC may also use their mailing lists to distribute residential educational materials, such as resident pet waste information, septic system handouts, and handouts on residential yard care, found on Think Blue Massachusetts’s website (Think Blue Massachusetts | Residents).

7.0       Schedule and Milestones (Elements F and G)

The project schedule and milestones presented in this section will enable project partners to track management activities over time as the Last Lakes and Knops Pond Watershed-Based Plan is implemented.

Table 7-1 provides a preliminary schedule for implementation of recommendations provided by this WBP. It is expected that the WBP will be reevaluated and updated in 2024, or as needed, based on ongoing monitoring results and other efforts. New projects will be identified through future data analysis, and stakeholder engagement and will be included in updates to the implementation schedule.

 

 

Table 7-1: Implementation Schedule and Interim Measurable Milestones

Structural & Nonstructural BMPs
Slope Stabilization 1 to 2 sites per year	Apply for 604b grant funding to prioritize sites and create conceptual designs.	Apply for Section 319 funding to implement BMPs.	Implement BMPs; Conduct annual maintenance on constructed BMPs; Apply for Section 319 funding for additional sites.
	12/1/2022	12/1/2023	12/1/2024
Dirt Road BMPs 1 road segment per year	Apply for Section 319 or 604b grant funding.	Improve 1 road segment per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Catch Basin Cleaning	Schedule meeting with Town of Groton to discuss catch basin cleaning schedule.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Maintenance	Schedule meeting with Town of Groton to discuss catch basin maintenance.	Perform annual inspections of catch basins and coordinate with Town if necessary.	N/A
	12/1/2022	12/1/2023	N/A
Catch Basin Inlet/Sump Modification	Apply for Section 319 or 604b grant funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024
Site-specific BMPs 1-2 per year based on prioritization matrix	Apply for Section 319 funding.	Construct 1-2 BMPs per year.	Perform annual maintenance on constructed BMPs.
	12/1/2022	12/1/2023	12/1/2024

 

Public Education & Outreach
Install Educational Kiosk	Install educational kiosk with BMP construction.
	12/1/2023

 

Monitoring
Monitoring Plan	Conduct four sampling events per year[10].
	Annually

 

8.0       Success Indicators and Evaluation (Element H)

The water quality target concentration(s) is presented under Element A of this plan. To achieve this target concentration, the annual loading must be reduced to the amount described in Element B. Element C of this plan describes the various management measures that will be implemented to achieve this targeted load reduction. The evaluation criteria and monitoring program described below will be used to measure the effectiveness of the proposed management measures (described in Element C) in improving the water quality of Lost Lake/Knops Pond:

• Indirect Indicators of Load Reduction. Indicators of excessive nutrient load include moderate to severe erosion and eutrophication in ponds or in Lost Lake/Knops Pond itself. Therefore, the absence of erosion, especially close to Lost Lake/Knops Pond or its tributaries, and/or the absence of eutrophication will indicate successful load reduction. In addition, nuisance algae and vegetation monitoring in Lost Lake/Knops Pond can also indicate water quality trends.
• Direct Indicators (Measurements) of Load Reduction. Results of the water quality monitoring will also indicate progress towards nutrient load reduction, specifically a reduction in phosphorus in both the Unnamed Tributary and in Martins Pond Brook. See Element I for more information about the water quality monitoring plan.
• Project-Specific Indicators. As previously discussed, the absence of erosion and eutrophication will likely indicate success in reducing the nutrient load. Specifically, areas near constructed watershed-wide or structural BMPs will indicate that these projects are successful.
  • Number of BMPs Installed. Element C of this WBP recommendations the installation of structural BMPs at six locations and recommends several watershed-wide BMPs. The anticipated pollutant load reduction has been documented for each proposed BMP, and the number of BMPs installed will be tracked and quantified as part of this program. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning and slope stabilization).
• TMDL Criteria. Lost Lake/Knops Pond is not currently subject to a non-native aquatic plant TMDL; therefore, this criterion is not applicable. However, please note that Lost Lake/Knops Pond does have a Mercury in Fish Tissue TMDL.

9.0 Monitoring Plan (Element I)

This WBP recommends implementation of a volunteer water quality monitoring program. The purpose of the monitoring program is to refine the location of and quantify sources of pollution. Through previous studies and the site visit, sources of pollution are reasonably well known; however, monitoring would allow for source contributions to be evaluated and quantified spatially. Because this program will help identify priority sources, it will lead to more effective implementation of BMPs. Additionally, monitoring will allow for a quantitative measure of BMP effectiveness by comparing concentrations of TP, TN, and TSS before and after the implementation of BMPs.  Elements of the recommended monitoring plan are summarized below:

• The monitoring plan locations were chosen based on accessibility and proximity to suspected sources of pollution and nutrients. In terms of accessibility, sampling locations were chosen to be close to a road or street and not along steep slopes. An exception is the Martins Pond Brook inlet which may need to be accessed via private property or by boat. The sampling locations chosen are downstream of suspected sources of pollution and nutrients to target areas identified as contributing pollution and nutrients to the watershed, based on previous reports and the site visit. Figure 9-1 shows the proposed monitoring locations. The monitoring locations are described below.
  • Outlet of Martins Pond Brook. This area, currently conservation land, features historical agricultural use. Previous reports have identified Martins Pond Brook as a source of phosphorus (ESS 2017).
  • Martin’s Pond at Lowell Street. This upstream area has historical and current agricultural use (Scarlet Hill Farm). Additionally, the Lowell Street culvert is fairly accessible for sampling.
  • Martins Pond Brook Inlet. The sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations.
  • Unnamed Tributary Inlet. This sampling location was chosen to determine if residential and developed areas are contributing to the phosphorus load.
  • Unnamed Tributary at Boston Road. Like the Martins Pond Brook inlet, this sampling location was chosen to determine if natural sources (e.g., forested land) are contributing to the phosphorus concentrations. The road crossing at this location provides accessibility.
• In-Lake Sampling. In-lake sampling is recommended to ensure that the in-lake phosphorus concentration remains below the target concentration of 50 ug/L. Samples could be taken at locations in Lost Lake/Knops Pond, specifically at the deepest locations (at multiple points in the water column) and at areas next to slopes noted for erosion due to stormwater runoff.
• At a minimum, sampling parameters should include TP, dissolved phosphorus, and total suspended solids.
• When to Sample. Sampling should be conducted during both dry and wet weather events to best capture the behavior of sources of pollution. A minimum of two dry and two wet weather events should be conducted annually in the fall, spring, and summer to assess temporal and seasonal trends.
• Quality Assurance/Quality Control (QA/QC). As the results from the volunteer monitoring program will be used for internal guidance only, developing a quality assurance project plan (QAPP) is not required. However, it should be noted that a QAPP is required to submit data to MassDEP and is recommended to help ensure data quality.
• Interpretation of Results/Data Analysis. The results of each sampling location should be compared both to the results of other sampling locations and to results from prior sampling events to determine seasonal trends, temporal trends, and/or the efficacy of any implemented solutions. By comparing the results at sampling locations upstream and downstream of each tributary, sources of pollution may be able to be determined. For example, comparing phosphorus results upstream and downstream of the forested area adjacent to the Martin’s Brook Pond tributary may help to determine if natural sources of phosphorus (i.e., leaf litter) are a large contributor to the overall phosphorus levels.
• Refinement of Monitoring Plan. Potential future changes to the monitoring plan include refining locations to pinpoint specific source areas; collecting runoff sampling from bare soil or agricultural areas if access is provided by the landowners; finger printing of inlet concentrations compared to solid soil data to further refine sources of pollution; additional in-lake or watershed septic source evaluations (e.g., DNA markets, advanced chemical indicators, nutrient isotopes); and additional in-lake monitoring at various depths throughout Lost Lake/Knops Pond.

 

 

Figure 9-1: Proposed Monitoring Locations.

10.0 Funding for Future Watershed Planning Phases and Implementation

10.1 Cost Estimate and Pollutant Load Reduction Estimates

Table 10-1 presents the estimated pollutant load reductions and costs for the proposed management measures.

 

Table 10-1: Proposed Management Measures, Estimated Pollutant Load Reductions and Costs[11].

Site-Specific BMP	Drainage Area (ac)	BMP Footprint (sf)/BMP Length (ft)	BMP Design Storm Depth (in)	Estimated Pollutant Removal			Estimated Annual O&M Costs[12]	Estimated Cost
				Total Phosphorus (lbs./year)	Total Nitrogen (lbs./year)	Total Suspended Solids (lbs./year)
Grotonwood Camp Raingarden	0.47	440 sf	0.5	0.5	4.0	191.2	$2,000	$21,200
Boat Launch Raingarden	0.47	405 sf	0.5	0.5	3.6	171.6	$2,000	$21,700
Boat Launch Swale	0.36	50 ft	0.5	0.1	0.1	42.2	$1,000	$12,800
Birchwood Avenue Swale	0.16	40 ft	0.5	0.1	0.2	45.5	$1,000	$5,700
Shattuck Street Lot Raingarden	1.23	445 sf	0.5	0.5	3.2	134.4	$2,000	$56,700
Shattuck Street Swale	0.36	60 ft	0.5	0.1	0.3	84.3	$1,000	$48,800

Note: ac is acres; sf is square feet; lbs./year is pounds per year; O&M is operation and maintenance.

Table 10-2 presents a priority matrix to guide future work and grant funding based on the following criteria:

• Cost/TP Removed. The estimated cost to construct the structural BMP divided by the pounds of total phosphorus removed per year to get a cost per pound of phosphorus removed.
• Cost/TN Removed. The estimated cost to construct the structural BMP divided by the pounds of total nitrogen removed per year to get a cost per pound of nitrogen removed.
• An evaluation of whether adequate space and topographical/geological conditions are available to construct the BMP (e.g., considering slope, soil type).
• Structural BMPs, especially raingardens with educational kiosks, can be used to educate the public about stormwater and water quality. Therefore, the visibility of each proposed structural BMP was considered (e.g., if it is in an often-used space, proximity to road).
• Public/Private. Constructing structural BMPs on public property tends to be more ideal than working with the landowner to install a BMP on private property.
• Proximity to Lake/Tributary. Structural BMPs installed close to the lake or a tributary will prevent nutrients and sediment from directly entering the lake without any attenuation. Therefore, these BMPs are prioritized.

The ranking is on a scale of one to five with five being the most optimal.

Table 10-2: Proposed Structural BMP Priority Matrix.

Structural BMP	Cost/TP Removed	Cost/TN Removed	Feasibility	Visibility	Public/ Private	Proximity to Lake/ Tributary	Sum	Rank
Slope Stabilization	4	4	4	3	5	5	25	High
Dirt Road BMPs	4	4	4	3	5	3	23	High
Catch Basin BMPs	5	5	5	1	5	3	24	High
Grotonwood Camp Raingarden	3	3	4	3	1	1	15	Low
Boat Launch Raingarden	3	1	3	4	5	5	21	High
Boat Launch Swale	5	5	4	3	5	4	26	High
Birchwood Avenue Swale	5	5	3	2	5	3	23	High
Shattuck Street Lot Raingarden	3	3	4	3	1	4	18	Medium
Shattuck Street Swale	4	4	4	2	5	3	22	High

Note: TP is total phosphorus and TN is total nitrogen.

10.2 Funding for Proposed Management Measures

The funding needed to implement the proposed site-specific BMPs (described in Element C) is presented in Table 10-3. The total cost for the program was estimated at $237,000 with estimated annual O&M costs of $14,500 or more. Table 10-3 presents the funding needed to implement the management measures presented in this watershed plan. The table includes costs for BMPs and operation and maintenance activities.

Table 10-3: Summary of Funding Needed to Implement the Watershed Plan.

Management Measures	Location	Capital Costs[13]	Annual O&M Costs	Relevant Authorities	Technical Assistance Needed	Funding Needed[14]
Watershed-wide BMPs (from Element C)
Slope Stabilization - Reseeding	Watershed-wide	$23,800 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$23,800
Slope Stabilization – Reseeding & Fabric Filter	Watershed-wide	$44,900 for 10,000 sf	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$44,900
Dirt Road BMPs	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Cleaning	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Maintenance	Watershed-wide	N/A	N/A	Coordinate with Town of Groton	N/A	N/A
Catch Basin Inlet/Sump Modification	Watershed-wide	$295 each plus labor costs	$1,475 for 5 replacement inserts plus labor	Town of Groton; GLA; GPAC	Permitting and Construction	$1,475 for 5 inserts plus permitting and labor costs
Site-specific BMPs (from Element C)
Bioretention and Rain Garden	Grotonwood Camp Raingarden	$21,216	$2,000	Town of Groton; Grotonwood Camp	Engineering Design and Construction	$21,216
Bioretention and Rain Garden	Boat Launch Raingarden	$21,676	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$21,676
Grassed Channel/Water Quality Swale	Boat Launch Swale	$12,811	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$12,811
Grassed Channel/Water Quality Swale	Birchwood Rd Swale	$5,693	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$5,693
Bioretention and Rain Garden	Shattuck Street Lot Raingarden	$56,727	$2,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$56,727
Grassed Channel/Water Quality Swale	Shattuck Street Swale	$48,753	$1,000	Town of Groton; GLA; GPAC	Engineering Design and Construction	$48,753
Information/Education (see Element E)
Monitoring and Evaluation (see Element H/I)
Total Funding Needed:						$237,000
Funding Sources:
MassDEP Section 319 and 604b Grants

11.0 Conclusions

As stated in Section 1.2 of this WBP, the long-term goal is to reduce total phosphorus and other nutrient and sediment loadings to Lost Lake/Knops Pond. The water quality goals (described in Section 5.2) will be accomplished through installation of BMPs throughout the watershed (described in Section 6.0) and will be measured through water quality monitoring efforts (described in Section 9.0). The action items for this WBP are described below.

• BMP Implementation. Implement BMPs throughout the watershed to achieve a 10% reduction in nutrient load as an interim goal. The required load reduction is 56 lbs./yr., 366 lbs./yr., and 9 tons/yr. for TP, TN, and TSS, respectively.
• Grant Funding. Apply for MassDEP Section 319 and 604b grants[15] for implementation of BMPs and additional planning, such as determining sites for slope stabilization.
  • Section 319 Nonpoint Source Grant. This program is used for implementation projects that address the prevention, control, and abatement of nonpoint source pollution. Generally, eligible projects must implement measures that target the major source(s) of nonpoint source pollution within a watershed, contain an appropriate method for evaluating the project results, and must address activities identified in the Massachusetts NPS Management Plan.
  • Section 604b Nonpoint Source Grant. This program is used for eligible entities to conduct watershed based nonpoint source assessment and planning projects that result in the following: development of preliminary designs and implementation plans that will address water quality impairments in impaired watersheds, determination of the nature, extent, and causes of water quality problems, and determination of pollutant loads necessary to meet water quality standards.
• Indicators of Success. The monitoring program and other indicators will be used to measure the effectiveness of the implemented BMPs.
  • Monitoring Program (Direct Measurements). Results of the water quality monitoring will indicate progress towards nutrient load reduction.
  • Indirect Indicators. Indirect indicators include the absence of eutrophication in ponds in the watershed and in Lost Lake/Knops Pond and the absence of erosion throughout the watershed. Watershed-wide BMPs that are initiated as part of this assessment can be included as indirect indicators of load reduction (for example, catch basin cleaning).
  • Project Specific Indicators. The number of BMPs installed will be tracked and quantified as part of this WBP.
• Long-Term Goals. The long-term goals will be adapted based on the results of the water quality monitoring and the indicators of success.

 

•  

12.0 References

314 CMR 4.00. 2013. Division of Water Pollution Control, Massachusetts Surface Water Quality Standards. https://www.arcgis.com/home/item.html?id=be2124509b064754875b8f0d6176cc4c.

ArcGIS. 2020a. USA Soils Hydrologic Group. Imagery Layer.

ArcGIS. 2020b. “USA Soils Water Table Depth.” Imagery Layer.

Cohen, A. J. and A. D. Randall. 1998. Mean annual runoff, precipitation, and evapotranspiration in the glaciated northeastern United States, 1951-80. Prepared for United States Geological Survey, Reston VA.

Geosyntec. 2014. Least Cost Mix of BMPs Analysis, Evaluation of Stormwater Standards Contract No. EP-C-08-002, Task Order 2010-12. Prepared for Jesse W. Pritts, Task Order Manager, U.S. Environmental Protection Agency.

Geosyntec. 2015. Appendix B: Pollutant Load Modeling Report, Water Integration for the Squamscott-Exeter (WISE) River Watershed.

 GLA. 2012. Lost Lake/Knops Pond Resource Management Plan. Prepared by Groton Lakes Association. Revision 4.01. August 12, 2012.

King, D. and P. Hagan. 2011. Costs of Stormwater Management Practices in Maryland Counties. University of Maryland Center for Environmental Science Chesapeake Biological Laboratory. October 11, 2011.

Leisenring, M., J. Clary, and P. Hobson. 2014. International Stormwater Best Management Practices (BMP) Database Pollutant Category Statistical Summary Report: Solids, Bacteria, Nutrients and Metals. Geosyntec Consultants, Inc. and Wright Water Engineers, Inc. December 2014.

Massachusetts Department of Revenue Division of Local Services. 2016. Property Type Classification Codes, Non-arm’s Length Codes and Sales Report Spreadsheet Specifications. June 2016.  https://www.mass.gov/files/documents/2016/08/wr/classificationcodebook.pdf

MassDEP. 2001. The Massachusetts Unpaved Roads BMP Manual. Prepared by Berkshire Regional Planning Commission and prepared for Massachusetts Department of Environmental Protection and U.S. Environmental Protection Agency. Winter 2001.

MassDEP. 2012. Massachusetts Year 2012 Integrated List of Waters Final Listing of Massachusetts' Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act.

MassDEP. 2016a. Massachusetts Clean Water Toolkit.

MassDEP. 2016b. Massachusetts Stormwater Handbook, Vol. 2, Ch. 2, Stormwater Best Management Practices.

MassDEP. 2019. Massachusetts Year 2016 Integrated List of Waters Final Listing of Massachusetts’ Waters Pursuant to Sections 305(b), 314 and 303(d) of the Clean Water Act. December 2019.

MassGIS. 1999. Networked Hydro Centerlines. Shapefile.

MassGIS. 2001. USGS Topographic Quadrangle Images. Image.

MassGIS. 2005. Elevation (Topographic) Data (2005). Digital Elevation Model.

MassGIS. 2007. Drainage Sub-basins. Shapefile.

MassGIS. 2009a. Impervious Surface. Image.

MassGIS. 2009b. Land Use (2005). Shapefile.

MassGIS. 2012. 2010 U.S. Census Environmental Justice Populations. Shapefile.

MassGIS. 2013. MassDEP 2012 Integrated List of Waters (305(b)/303(d)). Shapefile.

MassGIS. 2015a. Fire Stations. Shapefile.

MassGIS. 2015b. Police Stations. Shapefile.

MassGIS. 2017a. Town and City Halls. Layer.

MassGIS. 2017b. Libraries. Layer.

MassGIS. 2020. Massachusetts Schools (Pre-K through High School). Data layer.

MassGIS. 2021. Standardized Assessors’ Parcels. Mapping Data Set.

New Pig. 2021. “PIG® Oil & Sediment Catch Basin Filtration System – Large.” < Storm Drain Filter Insert for Oil & Sediment – New Pig>. Accessed November 19, 2021.

Solitude Lake Management. 2017. Annual Report 2017 Aquatic Vegetation Management Program Lost Lake & Knops Pond. Prepared for Groton Lakes Associated & Town of Groton. December 2017.

Schueler, T.R., L. Fraley-McNeal, and K. Cappiella. 2009. “Is impervious cover still important? Review of recent research.” Journal of Hydrologic Engineering 14 (4): 309-315.

United States Bureau of Labor Statistics. 2016. Consumer Price Index.

United States Geological Survey. 2016. National Hydrography Dataset, High Resolution Shapefile.

University of Massachusetts, Amherst. 2004. Stormwater Technologies Clearinghouse.

USDA NRCS and MassGIS. 2012. NRCS SSURGO-Certified Soils. Shapefile.

USEPA. 1986. “Quality Criteria for Water (Gold Book).” EPA 440/5-86-001. Office of Water, Regulations and Standards. Washington, D.C.

USEPA. 2010. EPA's Methodology to Calculate Baseline Estimates of Impervious Area (IA) and Directly Connected Impervious Area (DCIA) for Massachusetts Communities.

Voorhees, Mark, USEPA. 2015. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

Voorhees, Mark, USEPA. 2016a. “FW: EPA Region 1 SW BMP performance equations.” Message to Chad Yaindl, Geosyntec Consultants. January 25, 2016. E-mail.

Voorhees, Mark, USEPA. 2016b. “FW: Description of additional modelling work for Opti-Tool Project.” Message to Chad Yaindl, Geosyntec Consultants. April 23, 2015. E-mail.

 

Water Quality Assessment Reports

“Merrimack River Watershed 2004 Water Quality Assessment Report”

 

 

TMDL

No TMDL Found

 

 

 

 

 

 

 

 

APPENDICES

Appendix A – Pollutant Load Export Rates (PLERs)

 

Land Use & Cover1	PLERs (lb./acre/year)
	(TP)	(TSS)	(TN)
AGRICULTURE, HSG A	0.45	7.14	2.59
AGRICULTURE, HSG B	0.45	29.4	2.59
AGRICULTURE, HSG C	0.45	59.8	2.59
AGRICULTURE, HSG D	0.45	91.0	2.59
AGRICULTURE, IMPERVIOUS	1.52	650	11.3
COMMERCIAL, HSG A	0.03	7.14	0.27
COMMERCIAL, HSG B	0.12	29.4	1.16
COMMERCIAL, HSG C	0.21	59.8	2.41
COMMERCIAL, HSG D	0.37	91.0	3.66
COMMERCIAL, IMPERVIOUS	1.78	377	15.1
FOREST, HSG A	0.12	7.14	0.54
FOREST, HSG B	0.12	29.4	0.54
FOREST, HSG C	0.12	59.8	0.54
FOREST, HSG D	0.12	91.0	0.54
FOREST, HSG IMPERVIOUS	1.52	650	11.3
HIGH DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
HIGH DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
HIGH DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
HIGH DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
HIGH DENSITY RESIDENTIAL, IMPERVIOUS	2.32	439	14.1
HIGHWAY, HSG A	0.03	7.14	0.27
HIGHWAY, HSG B	0.12	29.4	1.16
HIGHWAY, HSG C	0.21	59.8	2.41
HIGHWAY, HSG D	0.37	91.0	3.66
HIGHWAY, IMPERVIOUS	1.34	1,480	10.2
INDUSTRIAL, HSG A	0.03	7.14	0.27
INDUSTRIAL, HSG B	0.12	29.4	1.16
INDUSTRIAL, HSG C	0.21	59.8	2.41
INDUSTRIAL, HSG D	0.37	91.0	3.66
INDUSTRIAL, IMPERVIOUS	1.78	377	15.1
LOW DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
LOW DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
LOW DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
LOW DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
LOW DENSITY RESIDENTIAL, IMPERVIOUS	1.52	439	14.1
MEDIUM DENSITY RESIDENTIAL, HSG A	0.03	7.14	0.27
MEDIUM DENSITY RESIDENTIAL, HSG B	0.12	29.4	1.16
MEDIUM DENSITY RESIDENTIAL, HSG C	0.21	59.8	2.41
MEDIUM DENSITY RESIDENTIAL, HSG D	0.37	91.0	3.66
MEDIUM DENSITY RESIDENTIAL, IMPERVIOUS	1.96	439	14.1
OPEN LAND, HSG A	0.12	7.14	0.27
OPEN LAND, HSG B	0.12	29.4	1.16
OPEN LAND, HSG C	0.12	59.8	2.41
OPEN LAND, HSG D	0.12	91.0	3.66
OPEN LAND, IMPERVIOUS	1.52	650	11.3
1HSG = Hydrologic Soil Group

 

Note: PLER is pollutant load export rate; lb./acre/year is pounds per acre per year; TP is total phosphorus; TSS is total suspended solids; and TN is total nitrogen.

 

 

 

Appendix B – Conceptual Design Sheets

 

[1] https://www.epa.gov/nps/handbook-developing-watershed-plans-restore-and-protect-our-waters

[2] Watersheds are defined by the WBP-tool by using MassGIS drainage sub-basins.

[3]Sources: MassGIS 1999, MassGIS 2001, USGS 2016

[4] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[5] Sources: MassGIS 2009b, MassGIS 1999, MassGIS 2001, USGS 2016.

[6] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[7] MassDEP’s 2016 Integrated List of Waters states that a TMDL is not required for this impairment (nonpollutant) (MassDEP 2019).

[8] Sources: MassGIS (2015a), MassGIS (2015b), MassGIS (2017a), MassGIS (2017b), MassGIS (2020), MA Department of Revenue Division of Local Services (2016), MassGIS (2005), ArcGIS (2020), MassGIS (2009b), MassGIS (2012), ArcGIS (2020b).

[9] Note: Massachusetts law limits phosphorus in lawn fertilizer.

[10] See Element I for additional monitoring plan information.

[11] The planning level cost estimates, pollutant load reduction estimates, and estimates of the BMP footprint were based off information obtained in the following sources and were also adjusted to 2016 values using the Consumer Price Index (United States Bureau of Labor Statistics 2016): Geosyntec Consultants, Inc. (2014, 2015), King and Hagen (2011), Leisenring, et al. (2014), MassDEP (2016a, 2016b), University of Massachusetts, Amherst (2004), Vorhees (2015, 2016a, 2016b).

[12] O&M costs are based on professional judgement, may vary significantly, and are subject to change.

[13] Estimated costs are AACE Level 4 conceptual level costs and may vary significantly.

[14] Funding needed value does not include annual operation & maintenance costs.

[15]Grants & Financial Assistance: Watersheds & Water Quality | Mass.gov.

 

 

 

 

 

 

 

 

 

 

 

 

 

Date: Jan 20, 2021 at 7:00 PM

Location: Zoom Meeting  -  https://us02web.zoom.us/j/89524981665?pwd =MjlQbW4zYlBaemhXRXVVQjREbHlaZz09

Meeting ID: 895 2498 1665
Passcode: 320894

       +1 929 205 6099 US (New York)

 

7:00 Call to order

7:00 Review of Geosynthec Report and discussion of path forward

 

8:00 Meeting minutes – Review, any updates and vote to the approval of previous minutes

 

8:05 Financial Summary

 

8:15 Duck Pond

 

8:25 Lost Lake / Knops Pond

- Treatment funding

 

8:35 Baddacook Pond

         

8:45 Whitney Pond

 

7:55 Adjourn

 

* Vote may be taken

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.

If there was previous agenda for this meeting it is below

Date: Jan 20, 2021 at 7:00 PM

Location: Zoom Meeting  -  https://us02web.zoom.us/j/89524981665?pwd =MjlQbW4zYlBaemhXRXVVQjREbHlaZz09

Meeting ID: 895 2498 1665
Passcode: 320894

       +1 929 205 6099 US (New York)

 

7:00 Call to order

7:00 Review of Geosynthec Report and discussion of path forward

 

8:00 Meeting minutes – Review, any updates and vote to the approval of previous minutes

 

8:05 Financial Summary

 

8:15 Duck Pond

 

8:25 Lost Lake / Knops Pond

- Treatment funding

 

8:35 Baddacook Pond

         

8:45 Whitney Pond

 

7:55 Adjourn

 

* Vote may be taken

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.

The listing of topics that the Chair reasonably anticipates will be discussed at the meeting is not intended as a guarantee of the topics that will have been discussed. Not all topics listed may in fact be discussed, and other topics not listed may also be brought up for discussion to the extent permitted by law.