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2023.06.30 Phase 1 PCP_Rev 1
TOWN OF LEXINGTON, MA PHASE 1 PHOSPHORUS CONTROL PLAN 0227871.12 June 2023woodardcurran.com 40 Shattuck Road | Suite 110 Andover, Massachusetts 01810 800.426.4262 Lexington, MA (0227871.12) i Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 TABLE OF CONTENTS SECTION PAGE NO. 1. INTRODUCTION................................................................................................................................1-1 1.1 Required PCP Implementation Schedule..............................................................................................1-1 1.2 Phase 1 of the PCP.........................................................................................................................................1-1 2. WATERSHED AND COMMUNITY CHARACTERIZATION...............................................................2-1 2.1 Watershed Characteristics...........................................................................................................................2-2 2.1.1 Hydrography........................................................................................................................................2-2 2.1.2 Land Cover............................................................................................................................................2-3 2.1.3 Land Use................................................................................................................................................2-3 2.1.4 Soils..........................................................................................................................................................2-4 2.2 Water Infrastructure.......................................................................................................................................2-4 2.3 Historic Stormwater Management Approach......................................................................................2-5 2.4 Economic Development Activity...............................................................................................................2-5 3. PHOSPHORUS LOAD REDUCTION TARGETS.................................................................................3-1 3.1 PCP Area.............................................................................................................................................................3-1 3.2 Baseline Load....................................................................................................................................................3-1 3.3 Change in Baseline Load Since 2005.......................................................................................................3-2 4. LEGAL ANALYSIS...............................................................................................................................4-1 4.1 Existing Regulations.......................................................................................................................................4-1 4.2 Planned Updates to Regulations..............................................................................................................4-3 4.3 Recommendations for Future Updates to Regulations and Programs .....................................4-3 4.3.1 Non-Structural Controls..................................................................................................................4-3 4.3.2 Structural Controls.............................................................................................................................4-4 5. FUNDING SOURCE ASSESSMENT....................................................................................................5-1 6. EXISTING STORMWATER CONTROLS.............................................................................................6-1 6.1 Non-Structural Controls...............................................................................................................................6-1 6.2 Structural Controls.........................................................................................................................................6-2 6.3 Phosphorus Load Reduction Gap.............................................................................................................6-3 7. PLANNED STORMWATER CONTROLS............................................................................................7-1 7.1 Non-Structural Controls...............................................................................................................................7-1 7.2 Structural Controls.........................................................................................................................................7-2 7.2.1 Municipal Parcel Evaluation...........................................................................................................7-3 7.2.2 Municipal Parcel Feasibility............................................................................................................7-3 7.2.3 Municipal Parcel Concepts.............................................................................................................7-3 7.2.4 Municipal Roadways.........................................................................................................................7-4 7.2.5 Redevelopment...................................................................................................................................7-6 7.3 Phosphorus Load Reduction Gap.............................................................................................................7-6 Lexington, MA (0227871.12) ii Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 8. OPERATION AND MAINTENANCE PROGRAM FOR STRUCTURAL CONTROLS .........................8-1 8.1 Existing O&M Program for Structural Controls..................................................................................8-1 8.2 Planned O&M Program for Structural Controls.................................................................................8-1 8.2.1 Tracking..................................................................................................................................................8-2 8.2.2 Education and Outreach..................................................................................................................8-2 8.2.3 Enforcement and Auditing .............................................................................................................8-2 9. PHASE 1 IMPLEMENTATION ...........................................................................................................9-1 9.1 Schedule.............................................................................................................................................................9-1 9.2 Cost......................................................................................................................................................................9-2 Lexington, MA (0227871.12) iii Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 TABLES Table 2-1: Lexington’s Impaired Waterbodies in the Charles River Watershed Table 2-2: Percent Impervious Area of Aggregate Land Use Categories Table 2-3: Area of Aggregate Land Use Table 3-1: Lexington’s PCP Area Table 3-2: 2005 Annual Stormwater Phosphorus Load Reduction Table 3-3: 2021 Stormwater Phosphorus Load Reduction Table 4-1: Town Regulations Supporting PCP Implementation Table 6-1: Non-Structural Control Phosphorus Reduction Factors Table 6-2: Non-Structural Controls Load Reduction Table 6-3: Estimated Existing Phosphorus Load Reduction Gap (lbs/year) Table 6-4: Anticipated Phosphorus Load Reduction Gap Table 7-1: Planned Non-Structural Control Phosphorus Reduction Factors Table 7-2: Planned Non-Structural Controls Load Reduction Table 7-3: Parcel Retrofit Summary Table 7-4: Roadway Retrofit Summary Table 7-5: Impervious Area Reduction Roadway Retrofit Summary Table 7-6: Town-Calculated Roadway Retrofit Summary Table 7-8: Estimated Planned Phosphorus Load Total 20-Year Reduction Gap (lbs/year) Table 7-9: Anticipated Phosphorus Load Reduction Gap Table 9-1: Phase 1 Implementation Cost Estimates WATERSHED FIGURES Figure 1: Hydrography Figure 2: 2016 Land Use Figure 3: Hydrologic Soil Groups Figure 4: Urbanized Area Figure 5: Roadway Jurisdiction APPENDICES Appendix A: Watershed Figures Appendix B: Baseline Load Appendix C: Funding Source Assessment Appendix D: Existing Non-Structural Control Credit Calcuations Appendix E: Existing Structural Controls Appendix F: Planned Non-Structural Control Credit Calculations Appendix G: Planned Structural Controls Appendix H: Private SCM Inspection Forms Appendix I: Implementation Cost Lexington, MA (0227871.12) 1-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 1. INTRODUCTION The Town of Lexington, Massachusetts (Town), under the requirements of the United States Environmental Protection Agency’s (EPA’s) Municipal Separate Storm Sewer System (MS4) General Permit, is required to develop and execute a Phosphorus Control Plan (PCP) for its stormwater discharges into the Charles River watershed. The PCP will be implemented in three phases; this report is the Phase 1 PCP (Plan). 1.1 Required PCP Implementation Schedule The MS4 General Permit (permit) PCP requirements are organized into 3 phases which are required to be implemented within a 20-year timeframe. The MS4 General Permit became effective July 1, 2018, and a modification to the MS4 General Permit became effective January 6, 2021. Graphic 1-1 below represents the schedule in 5-year MS4 General Permit-defined phases. Graphic 1-1: MS4 General Permit-Defined Phases 1.2 Phase 1 of the PCP Phase 1 plan elements (through Year 5) are outlined below in Graphic 1-2. This Plan provides a summary of stormwater-based phosphorus load reduction requirements, documents existing structural stormwater control measures (SCMs) and associated phosphorus load reduction credits, describes planned control measures to meet the Phase 1 Year 10 25% reduction requirement, outlines an operation and maintenance program for structural SCMs, and presents a Phase 1 implementation schedule and cost estimate. Years 1-5 July 2018-2023 •Create Phase 1 PCP Plan Years 5-10 July 2023-2028 •Implement Phase 1 PCP Plan •Create Phase 2 PCP Plan Years 10-15 July 2028-2033 •Implement Phase 2 PCP Plan •Create Phase 3 PCP Plan Years 15-20 July 2033-2038 •Implement Phase 3 PCP Plan Lexington, MA (0227871.12) 1-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Graphic 1-2: Phase 1 Plan Elements Year 2 June 30, 2020 Legal Analysis Year 3 June 22, 2021 Funding Source Assessment Year 4 June 30, 2022 Define Scope of PCP Year 5 June 30, 2023 Description of Phase 1 Planned Structural & Non-Structural Controls Description of O&M Program for Structural Controls Implementation Schedule & Estimated Cost Complete Written Phase 1 PCP Full Implementation of Non-Structural Controls Lexington, MA (0227871.12) 2-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 2. WATERSHED AND COMMUNITY CHARACTERIZATION The Charles River watershed consists of an approximate land area of 308 square miles. The river is approximately 80 miles long and spans from Echo Lake in Hopkinton, Massachusetts to Boston Harbor. The river flows through 23 communities and the watershed encompasses 35 communities, as shown in Graphic 2-1 below. The Charles River watershed is home to approximately one million residents. Graphic 2-1: Charles River Watershed Map by CRWA* *Map not to scale As an urban river, the Charles River is impaired by multiple pollutants. Three total maximum daily loads (TMDLs) have been developed for the watershed: one for pathogens and two for phosphorus (Upper/Middle and Lower Charles River Basins). A nearly five-decade cleanup effort has resulted in water quality improvements, primarily from elimination of industrial and municipal wastewater discharges and a Lexington, MA (0227871.12) 2-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 significant reduction in untreated sewage overflows discharging into the river. The primary challenge facing the river today is stormwater runoff. The nutrient phosphorus is transported to the river through stormwater runoff. In excessive quantities, phosphorus can lead to harmful algal blooms (HABs) and an associated reduction in the river’s dissolved oxygen levels, which can impact aquatic life and create toxic cyanobacteria outbreaks. Stormwater-based phosphorus sources in the urban environment typically consist of organic materials (leaves, grass clippings, etc.) washed off impervious areas during rain and snowmelt, sediments eroded from construction sites, wash off from winter sand application, and runoff containing phosphorus- based fertilizers. The Town of Lexington occupies a land area of approximately 16.7 square miles and is located eleven miles northwest of Boston. As of 2020, the Town had a population of approximately 34,500. While the Town is primarily residential, several industries and commercial establishments employ more than 16,000 people in the Town. Per the Town’s 2021 Comprehensive Plan Update Inventory: Land Use document, the Town is zoned approximately 63% residential, 4% commercial/industrial, 28% government civic, and 4% planned development. Approximately 68% of Lexington has been developed for roads, homes, stores, offices, light manufacturing companies, and their associated driveways and parking lots. The remaining land is undeveloped, in a natural state, or serves an open space use. The Town is within three major watersheds: the Charles River, the Mystic River, and the Shawsheen River. This Plan focuses on the portion of the Town within the Charles River watershed, herein referred to as the Watershed, which consists of approximately five square miles. Excessive stormwater runoff is generated by the built environment within the Town which, without control measures in place, can contribute stormwater- based pollutants to the Charles River watershed. Reducing stormwater runoff and phosphorus in the Town’s stormwater discharges are essential for the long-term sustainability and recovery of the Charles River. 2.1 Watershed Characteristics 2.1.1 Hydrography The Watershed contains multiple waterbodies, some impaired with one or more pollutants. Figure 1, included in Appendix A, identifies the waterbodies within the Watershed. Table 2-1 below outlines the major receiving waterbodies in the Watershed and their associated impairments as presented in the Massachusetts Draft 2022 303(d) List of Impaired Waters. Lexington, MA (0227871.12) 2-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 2-1: Lexington’s Impaired Waterbodies in the Charles River Watershed Waterbody Segment Impairments Beaver Brook (MA72-28) Algae, Chloride, Dissolved Oxygen, E. coli, Flow Regime Modification, Organic Enrichment (Sewage) Biological Indicators, Other Anthropogenic Substrate Alterations, Sedimentation/Siltation, Total Phosphorus, Water Chestnut Cambridge Reservoir (MA72014)Chloride Cambridge Reservoir, Upper Basin (MA72156)Aquatic Plants (Macrophytes), Chloride, Turbidity Unnamed Tributary (MA72-47)Chloride Unnamed Tributary (MA72-48)Chloride 2.1.2 Land Cover Impervious surfaces can contribute to increased stormwater runoff, route surface pollutants quickly to receiving waters, and restrict the recharge of groundwater. Pervious areas allow the infiltration of precipitation to recharge shallow and deep groundwater and preserve the hydrologic integrity of a watershed. Most impervious cover is made up of buildings, parking lots, driveways, and roads. The percentage of impervious cover in a watershed can indicate the probable health of the watershed and associated receiving waterbody. Extensive literature sources indicate that watersheds with greater than 10% of their land area covered by impervious surfaces exhibit various signs of impairment due to stormwater runoff. The Watershed consists of approximately 19% impervious area, as discussed in further detail in Section 2.1.3 below. 2.1.3 Land Use Land use is also an important factor when evaluating a watershed for sources of stormwater-based runoff pollution. In most cases, commercial, industrial, high- and medium-density residential, and highway land uses generate higher concentrations of pollutants in stormwater runoff than undeveloped or rural areas. Land use distribution per the Massachusetts Geographic Information System (MassGIS) 2016 Land Cover/Land Use dataset is illustrated in Figures 2A and 2B in Appendix A. Table 2-2 summarizes the percent of total impervious cover by land use category in the Watershed, and Table 2-3 summarizes the area distribution within each land use category. This data was presented in an EPA Region 1 memorandum dated April 22, 2014, with the subject Overview of Methodology to Calculate Baseline Stormwater Phosphorus Loads and Phosphorus Load Reduction Requirements for Charles River Watershed and is based on the MassGIS 2005 Land Use dataset. These tables will be updated as new data becomes available. As demonstrated in Table 2-2, commercial, industrial, high-density residential, and highway areas in the Town have higher percent impervious cover than other land use types, resulting in Lexington, MA (0227871.12) 2-4 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 higher concentrations of pollutants in stormwater runoff. Additionally, the Town’s overall percent total impervious area cover of approximately 19% is 1.9 times higher than the 10% impervious surface indicator for impairments due to stormwater runoff. As demonstrated by Table 2-3, the Watershed consists primarily of forest, medium-density residential, and commercial land use. Table 2-2: Percent Impervious Area of Aggregate Land Use Categories Community Commercial Industrial High Density Residential Medium Density Residential Low Density Residential Highway Open Land Agriculture Forest Overall % IA Lexington 55.0 57.9 37.5 28.4 25.7 60.7 9.4 8.2 2.8 19.2 Table 2-3: Area of Aggregate Land Use Community Units Commercial Industrial High Density Residential Medium Density Residential Low Density Residential Highway Open Land Agriculture Forest Overall Area Hectares 111.7 18.6 47.4 197.0 103.9 85.5 48.6 41.6 608.6 1262.9 Lexington Acres 276.0 46.0 117.1 486.8 256.7 211.3 120.1 102.8 1503.1 3120.7 2.1.4 Soils Based on data from the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS), the Watershed consists primarily of hydrologic soil group (HSG) B soils (26.2%), followed by HSG D (18.7%), HSG C (12.0%), and HSG A (2.1%) soils. The Watershed also has a significant area of not rated or not available soils (33.2%), which typically consist of developed land with human transported soil material (fill). HSG A generally has the lowest runoff potential and HSG D has the highest. Understanding watershed soils aids stormwater runoff mitigation decision making, since stormwater control measures are more effective on HSG A and B soils due to their high infiltration capacity. Figure 3 in Appendix A illustrates the locations of each hydrologic soil group in the Watershed. 2.2 Water Infrastructure Stormwater runoff in the Watershed is either captured and conveyed via an existing closed conduit drainage system or is conveyed via overland flow to waterbodies. The Town’s drain and sewer systems within the Watershed are separated. Most properties in the Watershed are connected to the sewer system, although there is a small percentage of properties with septic systems. It is important to note that the PCP only focuses on Town owned roadways and properties which excludes Massachusetts Department of Transportation (MassDOT) and Massachusetts Department of Conservation & Recreation (DCR) owned roadways and properties. Lexington, MA (0227871.12) 2-5 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 2.3 Historic Stormwater Management Approach Under the MS4 General Permit, the Town is required to implement a stormwater management program (SWMP) intended to reduce pollutants in stormwater. The Town’s latest SWMP, dated January 2022, outlines the activities and measures that the Town implements to meet the terms and conditions of the MS4 General Permit. The six minimum control measures, or main elements of the SWMP, include public education and outreach, public participation, illicit discharge detection and elimination (IDDE), management of construction site runoff, management of post-construction site runoff, and good housekeeping in municipal operations. To ensure that stormwater from development projects is adequately controlled, the Town has adopted a Stormwater Bylaw which establishes requirements for stormwater design and drainage management applicable for the following: 1. Any activity that results in a land disturbance greater than one acre of land, or any activity that disturbs less than one acre if that project is part of a larger common plan of development that eventually will disturb more than one acre of land; or 2. A new dwelling on a vacant lot, a new dwelling replacing an existing dwelling, or the reconstruction of an existing dwelling that is demolished to the extent of 50% or more of its replacement cost; or 3. Any development project that: a. Requires a special permit or site plan review; or b. Requires approval of a definitive plan under the Subdivision Control Law. In addition to the requirements outlined above, the Town of Lexington also regulates development within the jurisdiction of the Wetlands Protection Act. 2.4 Economic Development Activity A 2021 Economic Development Summary Report was developed for the Town. This report states that the Town’s economic development strategy places an emphasis on the following goals: 1. Creating large-scale commercial growth. 2. Attracting new life sciences companies. 3. Promoting vibrancy by working with both small and large corporate business owners. 4. Exploring the role of tourism as a function of economic development. Per the 2021 Economic Development Summary Report, there are 31 life science properties in Lexington. Two substantial business districts within the watershed include Forbes Road/Route 2A and Hayden Avenue District. Since 1979, 21 commercial properties have been rezoned through the Planned Development (PD) process. The PD process allows a property owner or developer to create a new zoning designation with new allowable uses, setbacks, floor-area ratios, parking counts, and more. Stormwater should continue to be an Lexington, MA (0227871.12) 2-6 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 important aspect of the PD process. Redevelopment of commercial properties presents a cost-effective opportunity for the Town to reduce the phosphorus load to the Charles River. Lexington, MA (0227871.12) 3-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 3. PHOSPHORUS LOAD REDUCTION TARGETS 3.1 PCP Area The PCP area is defined in the MS4 General Permit as being the PCP implementation area selected by the permittee. The permittee has the following options when defining the PCP area: •Option 1: The entire area within its jurisdiction within the Charles River watershed •Option 2: Only the urbanized area portion of its jurisdiction within the Charles River watershed. The Town of Lexington is within three major watersheds: the Charles River, the Mystic River, and the Shawsheen River. The entire portion of the Town within the Charles River watershed is urbanized, as shown in Figure 4 in Appendix A. Therefore, the PCP area is the entire area within the Town of Lexington’s municipal boundary within the Charles River watershed. The Town of Lexington’s PCP area excludes facilities regulated under separate National Pollutant Discharge Elimination System (NPDES) permits, including non-traditional (i.e., federal and state agency) MS4s. Non- traditional MS4s with facilities or roads in the Town of Lexington and in the Watershed include DCR, MassDOT, and Massachusetts Bay Transit Authority (MBTA). Area owned by these non-traditional MS4s was excluded from the Town of Lexington’s PCP area. These areas are summarized in Table 3-1 below and are identified in Appendix B. Table 3-1: Lexington’s PCP Area Area (Acres) Lexington’s Total Charles River Watershed Urbanized Land Area Non-Traditional MS4 Area Lexington’s PCP Area 3,138 397 2,741 3.2 Baseline Load Table 3-2 below summarizes the permit defined 2005 annual baseline and allowable phosphorus load and required load reduction for the Town of Lexington’s stormwater discharges into the Charles River watershed. Lexington, MA (0227871.12) 3-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 3-2: 2005 Annual Stormwater Phosphorus Load Reduction Annual Load (kg/yr / lbs/yr) Baseline Phosphorus Load (Permit - 2005) Allowable Phosphorus Load Phosphorus Load Reduction Requirement Percent Reduction in Phosphorus Load 530 / 1,168 287 / 633 243 / 535 46% 3.3 Change in Baseline Load Since 2005 The baseline load in Table 3-2 above was calculated by EPA using land use and land cover (LULC) data from 2005. It is anticipated that LULC changes have occurred since 2005 that could change the baseline load. As such, MS4 permittees are required to reflect and mitigate any increases in phosphorus load due to development since 2005. It is anticipated that the baseline phosphorus loads for the Charles River watershed communities will be updated in the next issuance of the MS4 General Permit using 2021 LULC data prepared by The University of Vermont’s (UVM) Spatial Analysis Laboratory in conjunction with the Charles River Watershed Association (CRWA). The 2021 LULC data will define land use and land cover consistently with the 2005 data used to develop the current MS4 Permit baseline loads. This will ensure that changes in load are due to development rather than inconsistencies with data resolution or categorization compared to the 2005 data. The updated 2021 LULC data is anticipated to be available to the public in July 2023. For the purposes of this Phase 1 PCP, an estimate of the Town’s updated baseline load was calculated using MassGIS 2016 LULC data. The 2016 baseline load was then used to forecast changes due to development through 2021 using a percent increase in impervious area. The forecasted load was projected through 2021 because this is source date of the UVM/CRWA LULC data. The baseline load calculations and methodology are detailed in Appendix B. Table 3-3 below presents the estimated 2021 baseline phosphorus load, which is being used as the target management goal for this Phase 1 PCP. This baseline load will be updated as needed to eventually reflect 2028 baseline loading in subsequent permit years. Lexington, MA (0227871.12) 3-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 3-3: 2021 Stormwater Phosphorus Load Reduction Load changes from development after 2021 through June 30, 2028 will be evaluated on a project-by-project basis using available permit documentation review. Annual Load (kg/yr / lb/yr) Updated Baseline Phosphorus Load (2021) Allowable Phosphorus Load Phosphorus Load Reduction Requirement Percent Reduction in Phosphorus Load Updated Phase 1 Permit Year 10 Reduction (lb/yr) 604.3 / 1,332.2 287 / 632.7 317.3 / 699.5 52.5%174.9 Lexington, MA (0227871.12) 4-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 4. LEGAL ANALYSIS The intent of the PCP legal analysis is to identify existing regulatory mechanisms available to the Town, such as bylaws and ordinances, and describe changes to the regulatory mechanisms that may be necessary to effectively implement all phases of the PCP across the public and private sectors. As summarized in Section 4.1 below, it appears that the Town of Lexington has the appropriate regulatory mechanisms in place to meet the planned Phase 1 phosphorus reduction goals outlined in this report. It is anticipated that updates to the Town’s regulations may be necessary in the future as the MS4 General Permit lifespan progresses into Phase 2 and Phase 3 of the PCP. Recommendations for potential updates to the Town’s regulations are summarized in Section 4.2 below. 4.1 Existing Regulations Table 4-1 below identifies existing regulatory mechanisms available to the Town that support various components of PCP implementation. Table 4-1: Town Regulations Supporting PCP Implementation Town Regulation Requirements Supporting PCP Implementation Stormwater Management Bylaw (Chapter 114) Thresholds for stormwater management requirements: •Any activity that results in a land disturbance greater than or equal to one acre; •Projects that are part of a larger common plan of development that eventually will disturb more than one acre of land; •A new dwelling on a vacant lot; •A new dwelling replacing an existing dwelling; •Reconstruction of an existing dwelling that is demolished 50% or more of its replacement cost; or •Development projects that require a special permit, site plan review, or approval of a definitive plan under the Subdivision Control Law. The Stormwater Agency may allow the applicant to contribute to the construction of a public or shared stormwater facility in lieu of an on- site stormwater facility where it has been demonstrated that there is no sufficient space for an on-site stormwater best management practice. Stormwater Management Regulations (Chapter 181, Article VI) Any applicable activity described in the Stormwater Management Bylaw section above is required to prepare a Stormwater Management Plan and Operations and Maintenance (O&M) Plan for review and approval by the Stormwater Agency. Lexington, MA (0227871.12) 4-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Town Regulation Requirements Supporting PCP Implementation Stormwater Management Regulations (Continued) (Chapter 181, Article VI) Phosphorus Removal Design Standards: The stormwater design shall remove 60% of the average annual load of Total Phosphorous (TP) generated from the total site area. O&M Requirements: The property owner responsible for the O&M of stormwater management facilities shall retain a Qualified Inspector who shall submit, on an annual basis by January 1st of each year, a written certification to the Town’s Engineering Division documenting that work has been done to properly operate and maintain the stormwater management facilities consistent with the approved O&M plan. Town Inspections: The Town’s Engineering Division may conduct periodic inspections of the project to ensure compliance with the conditions of the Stormwater Management Permit. Enforcement: Any person who violates any provision of the Town of Lexington’s Stormwater Management Bylaw, Stormwater Management Regulations, order, or permit issued may be fined up to $300 per offense, per day. Wetlands Protection Code (Chapter 130) Any proposed activity within a bank, freshwater wetland, marsh, bog, wet meadow, swamp, creek, river, stream, pond, lake, vernal pool habitat, land under water bodies, land subject to flooding, land bordering thereon as hereinafter defined, or riverfront area shall file a Notice of Intent (NOI) with the Conservation Commission to describe the proposed activity and its effect on the environment. An NOI application requires submission of a Stormwater Management Plan, which must detail the project’s compliance with the Massachusetts Stormwater Handbook and the Town’s Stormwater Management Bylaw and Regulations. The Stormwater Management Plan also must include a long-term O&M plan for any proposed structural controls. Planning Board Subdivision Regulations (Chapter 175) All subdivision projects must be designed to comply with the requirements described in the Stormwater Management Regulations section above. Planning Board Zoning Regulations (Chapter 176) Site Plan Review General Compliance: Projects shall comply with: •Town’s Stormwater Management Bylaw; •Rules and regulations of the Board of Health; •Massachusetts Department of Environmental Protection’s (MassDEP’s) Stormwater Management Regulations; and Lexington, MA (0227871.12) 4-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Town Regulation Requirements Supporting PCP Implementation •Town’s Wetlands Protection Code Site Design: All projects should demonstrate to the greatest extent feasible the utilization of the low impact development (LID) design, best management landscape design, and green site design features to reduce adverse impacts to the environment and public while aiding in the mitigation and management of stormwater, site design that manages and protects natural constraints, thermal pollution, and nonpoint and point source pollution. As summarized above, the Town of Lexington has several regulations in place that support stormwater management requirements including phosphorus removal design, long term O&M of SCMs, utilization of LID design, and more. As of June 2023, it appears that the Town of Lexington has the appropriate regulatory mechanisms in place to meet the planned Phase 1 phosphorus reduction goals outlined in this report. 4.2 Planned Updates to Regulations In Summer 2023, the Town is planning to update their Planning Board Zoning Regulations for new development to require the submittal of stormwater reports and long-term SCM O&M plans for all major site plan review projects. These new regulations will be consistent with the updated phosphorus removal and long-term O&M requirements in the Town’s recently updated Stormwater Management Regulations. 4.3 Recommendations for Future Updates to Regulations and Programs The development of additional regulations and programs may be necessary in the future as the Town progresses into Phase 2 and Phase 3 of the PCP. The sections below describe several potential regulatory and programmatic updates that could be considered to target phosphorus removal on private properties. 4.3.1 Non-Structural Controls The Town currently does not regulate implementation of non-structural controls, such as catch basin cleaning, street sweeping and leaf litter collection, on private property unless it is incorporated into a current stormwater permit under the Town’s Stormwater Bylaw and/or the Massachusetts Wetlands Protection Act. The Town does not have the authority to require non-structural controls for existing properties that were not subject to recent stormwater permit or conservation-based order of condition requirements. The Town may consider the following options in the future to enhance and expand implementation of non- structural controls to reduce total phosphorus loading associated with private properties: •Increase the level of funding within operations budgets to support a more aggressive municipal leaf litter collection program and, if necessary, offer an incentive for participating properties. Private landowners may welcome a municipal leaf litter collection program as many commercial facilities already finance these efforts. •Provide technical support and/or facilitate service contracts for non-structural controls that private property owners can access at a discounted cost. Lexington, MA (0227871.12) 4-4 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 •Develop a stormwater O&M program for collection of fees for the municipality to perform maintenance of structural or non-structural controls on private properties. •Amend the current Stormwater Management Bylaw to require non-structural controls and tracking on private property. This policy could be based on certain thresholds and property types, such as impervious cover or commercial/industrial uses. 4.3.2 Structural Controls The Town of Lexington updated their Stormwater Management Regulations in June 2022, and is planning to update their Planning Board Zoning Regulations in Summer 2023, to incorporate the phosphorus removal requirements specified in the MS4 General Permit and increase requirements related to the long-term O&M of structural SCMs on private properties. The Town’s Wetland Protection Code and Regulations have project review thresholds for relatively small increases in impervious surface and land alteration that obligate private land development and redevelopment to meet stormwater quality standards and promote infiltration. However, these regulations could be updated to be more consistent with phosphorus removal and long- term O&M requirements outlined in the Town’s Stormwater Management Regulations. The Town will be exploring how to further refine and codify these phosphorus removal requirements in future Wetland Protection Code and Regulations updates. The Town currently does not have the regulatory authority to require structural SCMs for existing private properties that are not undergoing redevelopment. There are several regulatory mechanisms and programs that the Town may consider to encourage or require structural controls to reduce phosphorus loading on private properties, including the following: •Consider updates to incentivize phosphorus control options using EPA Region 1 Performance Curves. •Develop a Town of Lexington Stormwater Design manual that guides land development applicants with selection of stormwater controls that provide the most beneficial stormwater nutrient controls. •Consider changes to Zoning requirements in Planned Commercial (CD) Zones and/or Transportation Management Overlay (TMO) Zones to encourage redevelopment and improvement of stormwater facilities on development parcels and roadways. •Develop a policy and guide to encourage Public/Private Partnerships. •Develop a Stormwater Grant Program to provide funding for non-residential property owners to design and construct stormwater retrofits. Lexington, MA (0227871.12) 5-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 5. FUNDING SOURCE ASSESSMENT A Funding Source Assessment was completed by Woodard & Curran for the Town of Lexington in June 2023 to provide an overview of existing and potential future State and Federal funding programs that may be available to the Town to assist with phosphorus reduction goals required by the MS4 General Permit. Possible funding entities include MassDEP State Revolving Fund Loan, Massachusetts Municipal Vulnerability Preparedness (MVP) Grants, Section 604(b) Water Quality Management Program, Coastal Pollutant Remediation Grant, and Massachusetts Division of Ecological Restoration (MassDER) Restoration and Revitalization Priority Projects Program. The Funding Source Assessment is included in Appendix C. The Town of Lexington also has access to internal Town funds, including enterprise funds and general funds, to support the Town’s phosphorus reduction efforts. In addition, the Town of Lexington is considering implementation of a stormwater utility fee and associated enterprise fund to establish a consistent income stream dedicated to funding stormwater infrastructure improvements. As of June 2023, it appears that the Town of Lexington has the appropriate funding needed to meet the planned Phase 1 phosphorus reduction goals outlined in the following sections of this report. It is anticipated that financing of the PCP will evolve as the MS4 General Permit lifespan progresses into Phase 2 and Phase 3 of the PCP and specific planned stormwater controls are designed and implemented. Lexington, MA (0227871.12) 6-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 6. EXISTING STORMWATER CONTROLS 6.1 Non-Structural Controls Non-structural pollution prevention practices prevent or reduce stormwater related runoff pollution by reducing the exposure and generation of pollutants that can be washed off impervious surfaces during precipitation events. Non-structural management approaches can also include public education and outreach, or new or refined regulatory policies that minimize creation or impact of land development, septic systems, or other sources of stormwater and groundwater pollution. Non-structural stormwater controls typically refer to stormwater runoff management practices that do not require extensive engineering design and construction efforts, hence the term non-structural. Non-structural controls provide important stormwater quality improvements for any given watershed but require careful planning and organization of labor resources, enforcement or incentives, education and outreach, and may require specialized equipment. The MS4 General Permit currently allows phosphorus removal credit for three non-structural control measures: enhanced sweeping, catch basin cleaning, and organic waste and leaf litter collection. Table 6-1 below outlines the Town’s current level of service for each of these non-structural controls and states the maximum phosphorus reduction factor the Town is allowed to take credit for per the operational standards defined in the MS4 General Permit. Table 6-1: Non-Structural Control Phosphorus Reduction Factors Non-Structural Control Current Level of Service Phosphorus Reduction Factor Defined by MS4 Permit Enhanced Sweeping Sweeping each municipally owned roadway, parking lot, and operated impervious surface within the Watershed with a mechanical broom sweeper three times per year; once in the spring and twice in the fall 1% annual reduction for sweeping two times per year; would need to sweep monthly to achieve increased credit Catch Basin Cleaning Cleaning municipally owned catch basins within roadways and on seven municipal properties annually 0% annual reduction; minimum catch basin cleaning frequency for credit is semi-annual Organic Waste and Leaf Litter Collection Sweeping each municipally owned roadway, parking lot, and operated impervious surface within the Watershed with a mechanical broom twice in the fall 0% annual reduction; minimum frequency for credit is weekly sweeping from September 1 to December 1 Implementing these non-structural control measures on municipal properties and roadways using the MS4 General Permit’s current crediting policy provides a phosphorus reduction of 1.9 lbs per year, as shown in Table 6-2 below. Lexington, MA (0227871.12) 6-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 6-2: Non-Structural Controls Load Reduction Phosphorus Load Reduction (lbs/year) Enhanced Sweeping Catch Basin Cleaning Organic Waste/ Leaf Litter Collection Total Municipally Owned Properties & Roadways 1.9 0.0 0.0 1.9 Calculations supporting this estimate are included in Appendix D. A figure denoting roadway jurisdiction is included as Figure 5 in Appendix A. The Town’s swept roadway area was estimated using a MassGIS 2022 roadway dataset by multiplying the road surface width by the segment length attributes of the municipally- accepted roads within the PCP area. 6.2 Structural Controls Using permitting documentation provided by the Town of Lexington’s Engineering Division, Conservation Commission, and Planning Department, Woodard & Curran identified existing structural SCMs which are creditable towards the Town’s phosphorus load reduction target. Structural SCMs are permanent structures and/or facilities constructed and operated to reduce the discharge of pollutants in stormwater by treating runoff via filtration, infiltration, and/or biological processes. A structural SCM is creditable towards the Town’s total phosphorus reduction requirement if it meets the design requirements outlined by EPA in the MS4 General Permit and is currently functioning as it was designed to. Non-residential and residential properties within the Town of Lexington were analyzed and reviewed by Woodard & Curran to estimate the total phosphorus reduction provided by existing structural SCMs. The phosphorus reduction was calculated using EPA’s Best Management Practice Accounting and Tracking Tool (BMP-BATT), which is a spreadsheet-based tool that provides accounting, tracking, and reporting for pollutant load reduction. The credit estimated for the 16 non-residential and 39 residential properties is summarized in Graphic 6-1. Of these, 5 properties with creditable SCMs are municipal. The existing structural control credit calculations are included in Appendix E.1. Graphic 6-1: Structural Controls Reduction (lbs/year) Credited SCMs were visually verified by Woodard & Curran to confirm these systems were constructed. Fact sheets documenting each credited SCM are included in Appendix E.2. The locations of each credited SCM are illustrated in a figure provided in Appendix E.3. Non-Residential = 55.8 Residential = 48.2 Total = 104.0 Lexington, MA (0227871.12) 6-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 There are likely additional existing structural controls within the Town that have not yet been reviewed or credited, including existing SCMs constructed prior to 2005. The total credit presented in this section is anticipated to be updated and refined throughout Phase 1 of the PCP. 6.3 Phosphorus Load Reduction Gap Table 6-3 below summarizes Lexington’s anticipated stormwater phosphorus load reduction gap estimated by crediting existing non-structural and structural controls as outlined above. Table 6-3: Estimated Existing Phosphorus Load Reduction Gap (lbs/year) Estimated Reduction Achieved Required Phosphorus Load Reduction Non-Structural Structural Total Non-Structural and Structural Reduction Estimated Load Reduction Gap 699.5 1.9 104.0 105.9 593.6 The MS4 General Permit requires that municipalities achieve reduction targets in a phased approach. Under Phase 1 of the PCP implementation, the Town of Lexington is obligated to meet 20% of the reduction target at the end of Permit Year 8 (July 2026) and 25% of this target at the end of Permit Year 10 (July 2028), as summarized in Table 6-4. Lexington, MA (0227871.12) 6-4 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 6-4: Anticipated Phosphorus Load Reduction Gap Target Milestones Reduction Required Reduction Provided by Existing Structural and Non-Structural Controls Estimated Load Reduction Gap Phase 1-Year 8 Reduction Requirement July 2026 20% (139.9 lbs/year) 15.1% (105.9 lbs/year) 4.9% (34.0 lbs/year) Phase 1-Year 10 Reduction Requirement July 2028 25% (174.9 lbs/year) 15.1% (105.9 lbs/year) 9.9% (69.0 lbs/year) Total 20-Year Permit Reduction Requirement July 2038 100% (699.5 lbs/year) 15.1% (105.9 lbs/year) 84.9% (593.6 lbs/year) Section 7 of this Plan summarizes planned controls to meet the Phase 1 reduction target of 25% by Year 10 (2028). Lexington, MA (0227871.12) 7-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 7. PLANNED STORMWATER CONTROLS 7.1 Non-Structural Controls The MassDEP and EPA have indicated that the next issuance of the MS4 General Permit, expected in late 2023 or early 2024, will include changes to the crediting policy for non-structural controls. These changes are likely to be based on recent work conducted by the University of New Hampshire’s Stormwater Center, along with an expert panel of state and regional regulators, experts in the field of watershed hydrology and stormwater management, stormwater consultants, and representatives of several municipalities. As stated in the memorandum titled “Clean Sweep – Recommendations for New and Updated Credits for Street Cleaning in New Hampshire” (Clean Sweep Memorandum), dated April 2023 and included in Appendix F, “science suggests that enhanced street cleaning practices can achieve pollutant reductions far beyond what is currently recognized in [existing] credit programs.” The Clean Sweep Memorandum focuses on crediting for enhanced street cleaning, which includes street sweeping and leaf litter collection on municipally owned roadways, parking lots, and operated impervious surfaces. It suggests two options for obtaining credit for enhanced street cleaning: a modeled approach and a measured approach. The proposed modeled approach is essentially an update to the current crediting policy, factoring in credit for area or lane miles swept, adopting a uniform medium density residential land use loading value for all areas swept, and changing the creditable sweeping frequencies. The proposed measured approach for crediting uses locally derived data paired with a crediting approach currently used in Minnesota to provide credit for collected organic matter based on mass. Additional data to support and refine the proposed modeled and measured approaches for enhanced street cleaning will be collected in 2023 and 2024. In anticipation of inclusion of these crediting approaches in the next issuance of the MS4 General Permit, which is expected during the implementation period of this Phase 1 PCP, the planned non-structural control reduction factors in Table 7-1 below are based on the proposed crediting methodologies outlined in the Clean Sweep Memorandum, utilizing the measured approach. The Town is also considering the purchase of new leaf litter collection equipment to increase their street cleaning capabilities and ultimately increase the mass of organic matter collected. The MassDEP and EPA have indicated that the next issuance of the MS4 General Permit is expected to include modifications to the catch basin cleaning crediting policy. These modifications may add a credit for annual catch basin cleaning in addition to the existing credit for semi-annual cleaning. With these forthcoming changes in mind, the planned non-structural control reduction factor for catch basin cleaning in Table 7-1 below is based on the anticipated changes to the crediting policy. Lexington, MA (0227871.12) 7-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 7-1: Planned Non-Structural Control Phosphorus Reduction Factors Non-Structural Control Planned Level of Service Anticipated Phosphorus Reduction Factor Defined by Future MS4 Permit Enhanced Street Cleaning Sweeping each municipally owned roadway, parking lot, and operated impervious surface within the PCP area with a mechanical broom sweeper at least three times per year: once in the spring and twice in the fall; additional leaf litter collection planned as allowable/feasible Reduction factor varies based on dry mass of collected street sweepings Catch Basin Cleaning Cleaning municipally owned catch basins within roadways and on seven municipal properties annually 1% annual reduction for annual cleaning Implementing these non-structural control measures on municipal properties and roadways using the MS4 General Permit’s anticipated crediting policy provides a phosphorus reduction of 52.6 lbs per year, as shown in Table 7-2 below. Table 7-2: Planned Non-Structural Controls Load Reduction Phosphorus Load Reduction (lbs/year) Enhanced Street Cleaning Catch Basin Cleaning Total Municipally Owned Properties & Roadways 49.5 3.1 52.6 Calculations supporting this estimate are included in Appendix F. 7.2 Structural Controls Planned structural controls have been assessed to meet the Town’s load reduction gap for Year 10. Phase 1 planned structural controls will be located on municipal parcels and roadways. The following process was completed to evaluate and prioritize planned structural controls on municipal parcels: 1. Evaluate each municipal parcel for stormwater retrofit potential (Completed in PY4). 2. Complete initial concept designs and estimate load reduction for top 5 opportunities (Completed in PY4). Lexington, MA (0227871.12) 7-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 3. Perform detailed feasibility assessment of top 5 opportunities (Completed in PY5). 4. Advance design of 3 opportunities (Completed in PY5). Additionally, concept designs for 8 planned structural controls on municipal roadways were prepared in PY4. The following subsections describe the work performed in each step of this process. 7.2.1 Municipal Parcel Evaluation There are 45 municipally owned parcels in the Watershed, 7 of which have been developed and have impervious cover. Each municipal parcel was assessed for retrofit potential to treat stormwater runoff generated on the parcel (on-site) and stormwater runoff from surrounding areas discharging onto or near the parcel (off-site). Of the seven municipal parcels with impervious cover on-site, 2 parcels were identified as having viable retrofit potential (Jonas Clarke Middle School at 17 Stedman Road and Bowman Elementary School at 9 Philip Road); 3 parcels currently treat nearly all on-site impervious cover (7 Crosby Road, 20 Pelham Road, and 39 Marrett Road); and 2 parcels have very minimal impervious cover and were assessed with the remaining 38 parcels for treatment of off-site impervious cover. The undeveloped parcels were assessed for regional SCMs to treat off-site runoff discharging onto or near these parcels via the Town’s existing closed conduit drainage system or overland flow. A high-level assessment was performed to estimate load reduction potential for each municipal parcel. The evaluation considered available end-of-pipe screening and monitoring results and used stormwater infrastructure mapping as required by the MS4 General Permit. Retrofit opportunity areas were ranked based on estimated phosphorus load reduction potential. This assessment is included in Appendix G.1. 7.2.2 Municipal Parcel Feasibility Based on discussions with the Town, the top 5 opportunities identified in the municipal parcel evaluation, as well as the 2 parcels with viable retrofit potential, were selected to prepare initial concept designs for. A detailed feasibility assessment of these initial concept designs was completed in PY5. A table outlining the concept feasibility is included in Appendix G.2. This assessment found that 3 of the concept designs were favorable to advance the design of in PY5 (Jonas Clarke Middle School, Bowman Elementary School, and Regional Retrofit 2 – Philip Road). The remaining 4 regional controls are primarily located on conservation land or are within or immediately adjacent to resource areas. Additionally, the favorable location for 2 of these regional controls (Munroe Road and Valleyfield Street 1) could require land easements. 7.2.3 Municipal Parcel Concepts Concept designs, potential load reduction, and cost estimates were prepared for the top 5 regional opportunities and the two parcels with viable retrofit potential, Jonas Clarke Middle School and Bowman Elementary School. The concept designs are presented in Appendix G.3. Table 7-3 below presents estimated phosphorus load reduction ranges. Ranges are provided since the phosphorus load reduction will vary based on further site investigations and data collection. The concept level phosphorus reduction calculations were completed using EPA Region 1’s BMP-BATT spreadsheet and are included in Appendix G.4. The total phosphorus load reduction across all sites is estimated to be 27-60 lbs/yr. Cost estimates for each project are discussed in Section 9 and included in Appendix I. Lexington, MA (0227871.12) 7-4 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 7-3: Parcel Retrofit Summary Retrofit Location (Concept Level)Estimated Load Reduction Range (lbs/year) Jonas Clarke Middle School (Advanced)1 – 3 Bowman Elementary School (Advanced)4 – 6 Regional Retrofit 1 – Munroe Road (Initial)1 – 5 Regional Retrofit 2 – Philip Road (Advanced)6 – 8 Regional Retrofit 3 – Green Lane (Initial)5 – 8 Regional Retrofit 4 – Valleyfield Street 1 (Initial)5 – 18 Regional Retrofit 5 – Valleyfield Street 2 (Initial)5 – 12 Total Estimated Load Reduction Range (lbs/year)27 – 60 7.2.4 Municipal Roadways There are over 80 acres of municipally owned roadway in the Watershed, and stormwater runoff from impervious cover outside of the municipal right-of-way may also be captured by municipal catch basins and treated. Potential roadway retrofit locations were selected for concepts based on the Town’s Road Surface Ratings and Repair Categories map provided in Appendix G.5. This map is a compilation of roadways that have been inspected and identified as requiring maintenance or rehabilitation. The eight selected roadways fit the Major Rehabilitation category. Retrofitting within these selected roadways provides an opportunity for the Town to address phosphorus removal credits as part of a broader roadway rehabilitation project. Structural retrofit concept figures for potential roadway retrofits are presented in Appendix G.6. The types of SCMs that have been selected across these roadways are infiltration trenches and biofiltration systems. The SCMs were sized to provide the highest phosphorus removal within the available right-of-way footprint. Phosphorus reduction calculations were completed using EPA Region 1’s BMP-BATT spreadsheet and are included in Appendix G.7. Phosphorus reduction is listed in order of highest potential load reduction in Table 7-4 below. Amongst the selected practices, infiltration trenches are likely to be the most cost-effective SCM. The total phosphorus load reduction across all sites is approximately 5.2 lbs/yr. Cost estimates for each project are discussed in Section 9 and included in Appendix I. Lexington, MA (0227871.12) 7-5 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 7-4: Roadway Retrofit Summary Retrofit Location SCM Type Load Reduction (lbs/year) Ewell Avenue Infiltration Trench 1.1 Benjamin Road Infiltration Trench 1.1 Valleyfield Street Infiltration Trench 1.0 Crosby Road Infiltration Trench 0.8 Clematis Road Enhanced Biofiltration 0.5 Elena Road Enhanced Biofiltration 0.4 Piper Road Infiltration Trench 0.3 Allen Street Biofiltration 0.02 Total Load Reduction (lbs/year)5.22 In addition to structural practices within municipal roadways, pavement removal was considered for the impervious cul-de-sacs at Clematis Road and Elena Road. Converting the center of the cul-de-sac to a pervious island provides phosphorus load reduction without the implementation of a SCM. Load reduction calculations are provided under Appendix G.7 and summarized in Table 7-5 below. Table 7-5: Impervious Area Reduction Roadway Retrofit Summary Retrofit Location Load Reduction (lbs/year) Clematis Road 0.06 Elena Road 0.06 Total Load Reduction (lbs/year)0.12 In addition to the opportunities noted above, four additional infiltration trench roadway retrofit locations were identified by the Town. The Town-calculated, total load reduction of the four retrofit locations yield approximately 2.2 lb/yr. Phosphorus reduction calculations are provided on Figure G-16 in Appendix G.6 and summarized in Table 7-6 below. Lexington, MA (0227871.12) 7-6 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 7-6: Town-Calculated Roadway Retrofit Summary Retrofit Location SCM Type Load Reduction (lbs/year) 250 Concord Avenue Infiltration Trench 0.7 272 Concord Avenue Infiltration Trench 0.6 11 Scott Road Infiltration Trench 0.3 12 Scott Road Infiltration Trench 0.6 Total Load Reduction (lbs/year)2.2 The total phosphorus load reduction across all roadway sites is estimated to be 7.5 lbs/yr. This load reduction is anticipated to occur through ongoing Town-wide roadway maintenance or rehabilitation redevelopment work, which will incorporate SCMs as the Town roads are being disturbed and repaved. 7.2.5 Redevelopment In addition to planned structural SCMs on municipal property, it is anticipated that the Town will be able to take credit for SCMs constructed through anticipated redevelopment projects during the implementation period of the Phase 1 PCP. A conservative estimate of load reduction through future projects permitted and constructed in the PCP Area is 1-2 lbs/yr. This is based on review of typical load reduction associated with previously permitted projects. A summary of the planned structural control load reduction ranges is provided in Graphic 7-1 below. Graphic 7-1: Planned Structural Controls Load Reduction (lbs/year) 7.3 Phosphorus Load Reduction Gap Table 7-8 and 7-9 below summarize Lexington’s anticipated stormwater phosphorus load reduction gap estimated by crediting existing and planned non-structural and structural controls. It is anticipated that Lexington will meet Phase 1 Year 10 reduction requirements with the planned controls presented in this Phase 1 PCP. The Phase 2 PCP will outline planned controls to meet the Phase 2 reduction target of 45% by Year 13 (2031) and 50% by Year 15 (2033). Municipal Parcels = 27 - 60 Municipal Roadways = 7.5 Redevelopment = 1 - 2 Total = 35.5 - 69.5 Lexington, MA (0227871.12) 7-7 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Table 7-8: Estimated Planned Phosphorus Load Total 20-Year Reduction Gap (lbs/year) Estimated Reduction Achieved Required Phosphorus Load Reduction Existing Structural Non-Structural Pending Permit Reissuance (Average) Planned Structural Pending Design (Average) Total Existing and Planned Average Estimated Load Reduction Gap 699.5 104.0 1.9 – 52.6 (25.7) 35.5 – 69.5 (52.5)182.2 517.3 Table 7-9: Anticipated Phosphorus Load Reduction Gap Target Milestones Reduction Required Reduction Provided by Existing and Planned Controls Estimated Load Reduction Gap Phase 1-Year 8 Reduction Requirement July 2026 20% (139.9 lbs/year) 26.0% (182.2 lbs/year) 0.0% (0 lbs/year) Phase 1-Year 10 Reduction Requirement July 2028 25% (174.9 lbs/year) 26.0% (182.2 lbs/year) 0.0% (0 lbs/year) Total 20-Year Permit Reduction Requirement July 2038 100% (699.5 lbs/year) 26.0% (182.2 lbs/year) 74.0% (517.3 lbs/year) It should be noted that the required phosphorus load reduction is anticipated to continuously change as development occurs in the Watershed. The required load reduction will be updated annually to reflect changes in phosphorus loading due to redevelopment. Lexington, MA (0227871.12) 8-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 8. OPERATION AND MAINTENANCE PROGRAM FOR STRUCTURAL CONTROLS Woodard & Curran and Town staff conducted a series of meetings to discuss the Town’s O&M program for existing structural controls on Town and private properties and evaluate steps to expand their O&M program for planned future structural controls. The goals of these meetings were the following: 1. Understand current inspection, maintenance, and tracking operations; 2. Understand current mechanisms to require and enforce maintenance of private controls; 3. Outline program updates to ensure the Town can efficiently credit existing and planned SCMs; and 4. Plan for implementation of program updates. The following subsections outline the Town’s existing and planned O&M programs for structural controls. The Town’s planned O&M program updates will be implemented by Permit Year 8 (2026). 8.1 Existing O&M Program for Structural Controls As described in Section 4.1 of this Plan, The Town’s Stormwater Management Regulations and Wetlands Protection Code include specific requirements for the submission and implementation of a long-term O&M plan for proposed structural controls. Additionally, the Stormwater Management Regulations require private property owners with structural controls to submit an annual certification to the Town documenting inspection and maintenance activities conducted in accordance with the O&M plan for their facility. These regulations also include enforcement actions the Town can pursue if property owners are not meeting their O&M requirements. The Town is planning to update their Planning Board Zoning Regulations in Summer 2023 to align with the long-term O&M requirements included in the Town’s Stormwater Management Regulations. Until those updates are adopted, the Town’s Planning Board Subdivision and Zoning Regulations require compliance with the Stormwater Management Regulations and Wetlands Protection Code where applicable, and therefore also require long-term O&M for structural controls. The Town’s Engineering Division, Conservation Commission, and Planning Department each separately track and maintain records of design plans and O&M plans for structural controls submitted to their respective departments as part of permitting applications. As described in Section 6.2 of this Plan, Woodard & Curran used the permitting documentation provided by each of these Town departments to develop a Town-wide inventory of existing structural SCMs that are creditable towards the Town’s phosphorus load reduction target. The Town’s Engineering Division confirms private SCMs have been built when they conduct final site inspections as part of their Stormwater Permit process. Similarly, the Conservation Commission confirms the construction of private SCMs during the Certificate of Compliance process, which is a requirement to close out all Town issued Order of Conditions. 8.2 Planned O&M Program for Structural Controls The Town’s O&M program updates will focus on tracking, education and outreach, and enforcement and auditing for private SCM owners. The Town’s Engineering Division, Conservation Commission, and Planning Lexington, MA (0227871.12) 8-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Department will be the primary parties responsible for these components of the O&M program. Program updates are anticipated to be implemented in phases to align with MS4 PCP implementation. Updates described herein focus primarily on program updates in support of Phase 1 PCP implementation. 8.2.1 Tracking Tracking and documenting SCMs and their inspection and maintenance activities is necessary for the Town to take phosphorus reduction credit for these structural controls. The Town is considering program implementation of a Town-wide tracking software where the Town’s Engineering Division, Conservation Commission, and Planning Department can each input information on the proposed structural SCMs and O&M plans they have approved as part of their individual permitting processes. This will help the Town maintain an updated inventory of private structural SCMs and could also be used to track phosphorus load reduction credits for each SCM and receipt of annual O&M certifications. 8.2.2 Education and Outreach Education and outreach are critical to a successful private SCM O&M program. Planned program updates for education and outreach may include components such as: •Mailings notifying private property owners of the presence of an SCM on their property, including information on how to care for the SCM; •Workshops for private property owners to attend to learn about SCM inspections and maintenance; and •Lists of available resources for private property owners to learn more about SCMs or solicit contractor services to conduct inspections and maintenance of SCMs on their behalf. In addition, the Town has prepared inspection forms to provide to private property owners that are tailored to the type(s) of SCM on their properties. These forms are included in Appendix H. 8.2.3 Enforcement and Auditing The Town’s Stormwater Management Regulations outline the Town’s authority for enforcing long-term O&M of private structural SCMs. The Town is updating their Planning Board Zoning Regulations in Summer 2023 to align with these long-term O&M requirements and will need to update their Wetlands Protection Code and Regulations in the future to also include these requirements for consistency across departments. Improvements to tracking systems, as described in Section 8.2.1, can assist with documenting annual certification processes and support future enforcement. An auditing program may be enacted to ensure the credibility of the self-certification reporting of private SCMs. The Town’s Stormwater Management Regulations, Planning Board Subdivision and Zoning Regulations, and Wetlands Protection Code and Regulations would need to be modified to outline the auditing program and provide municipal staff authorization to inspect existing SCMs as part of the auditing process. Lexington, MA (0227871.12) 9-1 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 9. PHASE 1 IMPLEMENTATION 9.1 Schedule As required by the MS4 General Permit, the Town has prepared an implementation schedule for planned Phase 1 SCMs. Graphic 9-1 below outlines the Phase 1 implementation schedule elements for Permit Year 6 (2024) through Permit Year 10 (2028). The primary elements of the schedule include: •Annual inspection and maintenance of municipal SCMs: o The Town will annually inspect and maintain (as needed) municipal SCM to ensure systems continue to operate as designed. •Private SCM education and outreach: o The Town plans to commence private SCM owner education and outreach in Permit Year 6 as outlined in Section 8.2.2. o If needed, the Town will continue education and outreach activities to engage private SCM owners throughout Phase 1. •Implement planned structural SCMs: o The Town will implement planned structural SCMs to meet their Phase 1 reduction requirement, informed by the concept designs and planning work outlined in Section 7. A 10 pound per year reduction goal for implementing SCMs is included in Graphic 9-1. This is likely to change as annual performance evaluations are completed. •Annual performance evaluation: o The Town will evaluate the effectiveness of the PCP by tracking phosphorus reductions through implemented SCMs and baseline load increases due to development. •Phase 2 Plan: o The Phase 2 PCP will be completed in Permit Year 10. Lexington, MA (0227871.12) 9-2 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 Graphic 9-1: Implementation Schedule Elements 9.2 Cost Per the MS4 General Permit, the Town has estimated the cost of implementing the Phase 1 Plan. The implementation cost includes three elements: non-structural SCMs; municipal SCM inspection, operation, and maintenance; and planned structural SCMs. The non-structural SCMs and municipal SCM O&M costs are annual, recurring costs while the planned structural SCM cost is a one-time capital cost. The annual non-structural SCM cost is approximately $100,250. This was developed using Town-wide street sweeping and catch basin cleaning costs provided by the Town. The Town-wide totals were multiplied by the estimated percent of municipal road length and catch basins in the PCP area to estimate the PCP area non-structural SCM cost. O&M costs were developed for existing and planned structural control measures which are or will be maintained by the Town. The estimated O&M costs are based on system type, number of municipal systems, typical maintenance activities for that system type and their associated frequencies. Hourly durations for labor and the equipment necessary to execute each activity were estimated. The annual O&M cost conservatively assumes each municipal SCM needs to be maintained annually at the frequencies presented in the O&M cost breakdown in Appendix I. However, the necessary maintenance frequency will be reassessed based on annual inspections. Town-provided labor rates and local equipment costs are used. Additionally, components of existing and planned structural controls are anticipated to require replacement; an average 30-year system lifespan was assumed. O&M costs are anticipated to be phased in conjunction with the construction of planned structural SCMs to meet Permit Year 8 and 10 implementation requirements. Existing structural SCMs are anticipated to account for approximately half of the total O&M cost based on the number of systems. Construction of planned structural controls is anticipated to be completed between Permit Year 8 and 10, with the majority completed in Permit Year 9. The remaining half of the total O&M cost is assumed to be accrued starting in Permit Year 8. Year 6 June 30, 2024 Inspect & Maintain Municipal SCMs Commence Private SCM Education/Outreach Implement structural SCMs for 10 lbs of reduction Performance Evaluation Year 7 June 30, 2025 Inspect & Maintain Municipal SCMs Continue Private SCM Education/Outreach Implement structural SCMs for 10 lbs reduction Performance Evaluation Year 8 June 30, 2026 Inspect & Maintain Municipal SCMs Implement structural SCMs for 10 lbs reduction Performance Evaluation Year 9 June 30, 2027 Inspect & Maintain Municipal SCMs Implement structural SCMs for 10 lbs reduction Performance Evaluation Year 10 June 30, 2028 Inspect & Maintain Municipal SCMs Implement structural SCMs for 10 lbs reduction Performance Evaluation Complete Phase 2 Plan Lexington, MA (0227871.12) 9-3 Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 The planned structural SCM costs include an assumed cost for survey, geotechnical investigation, design, permitting, bidding, and construction administration, in addition to a 25% design and 20% owner’s contingency. The total planned structural SCM cost estimate of $6,715,000 has been distributed evenly over the next 5 years (Permit Year 6 through 10) for planning purposes. Total cost estimates organized by permit year and implementation cost element are summarized in Table 9-1 below. Supporting cost estimates and associated calculations are included in Appendix I. Table 9-1: Phase 1 Implementation Cost Estimates Permit Year Non-Structural SCM Cost Municipal SCM O&M Cost Planned Structural SCM Cost Total Cost PY 6 (June 30, 2024)$100,250 $560,500 $1,343,000 $2,003,750 PY 7 (June 30, 2025)$100,250 $560,500 $1,343,000 $2,003,750 PY 8 (June 30, 2026)$100,250 $1,121,000 $1,343,000 $2,564,250 PY 9 (June 30, 2027)$100,250 $1,121,000 $1,343,000 $2,564,250 PY 10 (June 30, 2028)$100,250 $1,121,000 $1,343,000 $2,564,250 Total Cost $501,250 $4,484,000 $6,715,000 $11,700,250 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX A: WATERSHED FIGURES Figure 1: Hydrography Figure 2: 2016 Land Use Figure 3: Hydrologic Soil Groups Figure 4: Urbanized Area Figure 5: Roadway Jurisdiction I-95 R O U T E 2 C O N C O R D A V E N U EWALTHAM STREETH A Y D E N A V E N U E PLEASANT STREETSPRING STREETLINCOLNSTREETMARRETT - 2A M ID D L E S T R E E T WATERTOWN STREETMARRETT - 2ACambridgeReservoirHo b b s B r o o kHobbs BrookHobbsBrookH o b b s B r o o k Beaver Brook Mill Brook M u n r o e B ro o k Stony Brook BeaverBrook-CharlesRiver UpperShawsheenRiver Legend±Figure 1Hydrography Charles River WatershedPhosphorous Control Program Figure Exported: 6/29/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\Watershed_HUC12.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: ESRI Imagery Service, MassGIS, USGS Charles River Basin Lexington Boundary HUC12 Boundary SPRING STREETM ID D L E S T R E E T CONCORD AVENUEHAYDEN A V E N U E WAL T HAMSTREETL IN C O LN S T R E E T MARRETT - 2A WALTHAM STREETMARRETT-2AI-9 5 R O U T E 2LINCOLNSTREET Legend±Figure 2ALand Use Areas(Western Watershed)Charles River WatershedPhosphorous Control Program Figure Exported: 6/29/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\Watershed 2016 Land Use.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: ESRI Imagery Service, MassGIS, USDA Charles River Basin Lexington Boundary Land Use Category Commercial/Industrial High Density Residential Medium Density Residential Open Right-of-Way SPRING STREETMIDDLESTRE E T CONCORD AVENUEHAYDEN A V E N U E WAL T HAMSTREETMARRETT - 2A WALTHAM STREET WATERTOWNSTREETMARRETT-2AI-9 5 R O U T E 2LINCOLNSTREETPLEASANT STREETLegend±Figure 2BLand Use Areas(Eastern Watershed)Charles River WatershedPhosphorous Control Program Figure Exported: 6/29/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\Watershed 2016 Land Use.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: ESRI Imagery Service, MassGIS, USDA Charles River Basin Lexington Boundary Land Use Category Commercial/Industrial High Density Residential Medium Density Residential Open Right-of-Way I-95 R O U T E 2 C O N C O R D A V E N U EWALTHAM STREETH A Y D E N A V E N U E PLEASANT STREETSPRING STREETLINCOLNSTREETMARRETT - 2A M ID D L E S T R E E T WATERTOWN STREETMARRETT - 2ALegend±Figure 3Hydrologic SoilsCharles River BasinPhosphorous Control Program Figure Exported: 6/29/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\Hydrologic Soils.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: ESRI Imagery Service, MassGIS, USDA Charles River Basin Lexington Boundary Hydrologic Soil Group A A/D B B/D C C/D D Not rated or not available Non-Residential Zoning Impervious Surface Residential Zoning Impervious Surface NPDES Phase II Stormwater ProgramAutomatically Designated MS4 Areas US EPA Region 1 GIS Center Map #8824, 8/9/2013 0 1 2 3 Kilometers 0 1 2 3 Miles MA ME NH RI VT CT Lexington MA 31366 31366Town Population:Regulated Population: Urbanized Areas, Town Boundaries: US Census (2000, 2010)Base map © 2013 Microsoft Corporation and its data suppliers (Populations estimated from 2010 Census) .Regulated Area: UA Based on2000 Census UA Based on2010 Census I-95 R O U T E 2 C O N C O R D A V E N U EWALTHAM STREETH A Y D E N A V E N U E PLEASANT STREETSPRING STREETLINCOLNSTREETMARRETT - 2A M ID D L E S T R E E T WATERTOWN STREETMARRETT - 2ALegend±Figure 5RoadwayJurisdictionCharles River WatershedPhosphorous Control Program Figure Exported: 6/29/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\Roadway Jurisdiction.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: ESRI Imagery Service, MassGIS Charles River Basin Lexington Boundary Impervious Area Roadway Jurisdiction Town Accepted Private; Unaccepted; Driveway Mass Highway Dept. of Conservation and Recreation Department of Defense Zoning Group Government/Civic Commercial/Industrial District; Planned Commercial; Planned Residential Residential Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX B: BASELINE LOAD B.1: Baseline Load Memo B.2: Attachment 1 - Figure B.3: Attachment 2 - Calculations Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 B.1: Baseline Load Memo 40 Shattuck Road | Suite 110 Andover, Massachusetts 01810 www.woodardcurran.com T 800.426.4262 T 978.557.8150 F 978.557.7948 MEMORANDUM PROJECT: Lexington, MA Phosphorus Control Plan PROJECT NUMBER: 0227871.12 DATE: June 2023 SUBJECT: Baseline Load Memorandum The MS4 General Permit requires permittees to account and mitigate for any phosphorus load increases due to development since 2005. This memorandum summarizes the methodology used to update the Town of Lexington’s baseline total phosphorus load due to development within the PCP area. 1.1 PCP Area The PCP area is defined in the MS4 General Permit as being the PCP implementation area selected by the permittee. The Town of Lexington’s PCP area excludes facilities or areas regulated under separate National Pollutant Discharge Elimination System (NPDES) permit. These include non-traditional (i.e. federal and state agencies) Municipal Separate Storm Sewer Systems (MS4s), such as the Massachusetts Department of Conservation and Recreation (MassDCR) and Massachusetts Department of Transportation (MassDOT). Lexington’s PCP area was estimated by excluding the non-traditional MS4 areas from the total Town area. The non-traditional MS4 area includes parcels and roadways. A figure showing the parcels and roads excluded from Lexington’s PCP area is attached. Table 1 below summarizes Lexington’s PCP area. TABLE 1: LEXINGTON’S PCP AREA Area (Acres) Lexington’s Total Charles River Watershed Urbanized Land Area Non-Traditional MS4 Area Lexington’s PCP Area 3,138 397 2,741 1.1.1 Parcels The non-traditional MS4 parcel area was estimated using MassGIS 2020 parcel data property type classification codes (Use Codes). The non-traditional MS4 area, excluded from Lexington’s PCP area, consists of the following Use Codes: Lexington, MA (0227871.12) 2 Woodard & Curran, Inc. Appendix B: Baseline Load Memorandum June 2023 90 Public Service Properties · 901 – (Intentionally left blank) 91 Commonwealth of Massachusetts – Reimbursable Land · 910 – Department of Conservation and Recreation, Division of State Parks and Recreation · 912 – Department of Corrections, Division of Youth Services · 915 – Department of Conservation and Recreation, Division of Water Supply Protection · 917 – Education – University of Massachusetts, State Colleges, Community Colleges 92 Commonwealth of Massachusetts – Non-Reimbursable Land · 920 – Department of Conservation and Recreation, Division of Urban Parks and Recreation · 922 – Department of Corrections, Division of Youth Services, Mass Military, State Police, Sheriffs’ Departments · 924 – Mass Highway Department · 925 – Department of Conservation and Recreation Division of Water Supply Protection conservation restrictions and sewer easements, Urban Parks · 927 – Education – University of Massachusetts, State Colleges, Community Colleges 97 Authorities · 972 – Transportation Authority · 975 – Vacant, Transportation Authority 1.1.2 Roadways The non-traditional MS4 roadway area was estimated using roadway jurisdiction and Right-Of- Way width data. MassDOT and MassDCR roadway area was excluded from Lexington’s PCP area. 1.2 Baseline Load Update Lexington’s updated baseline load due to development was calculated using two approaches: 1. Using MassGIS 2016 land use land cover data and Brown & Caldwell’s baseline load spreadsheet 2. Using MassGIS 2016 land cover data and applying a percent increase in impervious area compared to EPA’s 2005 data Both approaches excluded non-traditional MS4 areas. Approach 1 introduces inconsistencies with land use definitions between MassGIS 2005 LULC and MassGIS 2016 LULC, whereas Approach 2 only uses the land cover data from MassGIS 2016. Therefore, Approach 2 eliminates the inconsistency between 2005 and 2016 land use definitions. Table 2 below summarizes the findings from both approaches, and baseline load calculations are attached. Lexington, MA (0227871.12) 3 Woodard & Curran, Inc. Appendix B: Baseline Load Memorandum June 2023 TABLE 2: APPROACH 1 AND 2 RESULTS Approach Change in Baseline Load (lbs/year) 2016 2021 Projected Approach 1 34.1 49.6 Approach 2 112.5 163.7 Approach 2 results were used in this PCP. Approach 2 compared the change in impervious cover between 2005 and 2016 data. The 2016 data showed an increase in impervious area of about 60 acres. Approach 2 calculation steps are outlined below: 1. A percent increase in the impervious area between 2005 and 2016 was calculated (approximately 13.5%). 2. The 2005 impervious area breakdown by land use was increased by 13.5% to distribute this increase in impervious area over each land use type. 3. These areas were multiplied by their respective phosphorus load export rate (PLER) and summed to estimate the increase in baseline phosphorus load between 2005 and 2016. 4. The impervious area percent increase between 2005 and 2016 (11 years) was projected to 2021 (16 years). The impervious area percent increase from 2005 to 2021 was estimated to be approximately 19.6%. 5. Steps 2 and 3 were repeated to estimate the increase in baseline phosphorus load between 2005 and 2021. Approach 2 results for 2021, summarized in Table 2 below, were used to estimate Lexington’s phosphorus load reduction requirement and to inform this Phase 1 PCP. TABLE 3: 2021 STORMWATER PHOSPHORUS LOAD REDUCTION Annual Load (kg/yr / lb/yr) Updated Baseline Phosphorus Load (2021) Allowable Phosphorus Load Phosphorus Load Reduction Requirement Percent Reduction in Phosphorus Load Updated Phase 1 Permit Year 10 Reduction (lb/year) 604.3 / 1,332.2 287 / 632.7 317.3 / 699.5 52.5% 174.9 Based on the updated baseline load, the Year 10 reduction requirement of 174.9 represents an additional reduction of 41.1 lbs beyond the permit requirement (139.9 lbs). The associated Lexington, MA (0227871.12) 4 Woodard & Curran, Inc. Appendix B: Baseline Load Memorandum June 2023 updated Year 8 reduction of 139.9 lbs is an additional 32.9 lbs beyond the permit requirement (107.0). It is anticipated that the baseline load will be updated using 2021 LULC data prepared by the University of Vermont’s Spatial Analysis Laboratory in conjunction with the Charles River Watershed Association. This data is anticipated to be available July 2023. The 2021 LULC data defines land use and land cover consistently with the 2005 data the permit used. This ensures that changes in load are due to development rather than inconsistencies with data resolution or categorization compared to the 2005 data. Load changes from development after 2021 through June 30, 2028 will be evaluated on a project-by-project basis using available permit documentation review. Attachments Attachment 1: Non-Traditional MS4 Area Figure Attachment 2: Calculations Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 B.2: Attachment 1 – Figure Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan,METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS User Community Legend±Figure 7State LandsCharles River BasinPhosphorous Control Program Figure Exported: 6/15/2023 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.12 Lexington MA - FY23 MS4 Compliance\wip\GIS\Projects\State Lands.mxdProject #: 0227871.12Map Created: June 202300.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Charles River Basin Lexington Boundary MassDOT/DCR Parcel Right of Way (324 Acres) Commonwealth of Massachusetts Parcels (75 Acres) Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 B.3: Attachment 2 – Calculations Baseline Load Update June 2023 A B A B C C/D D Unk Total A B C C/D D Unk A B C C/D D Unk Total Commercial 609.3 164.6 27% 0.4 1.2 20.9% 127.3 1.78 226.6 60.3 237.3 88.1 58.9 444.7 0.04 0.18 0.36 0.46 0.54 0.36 2.4 42.7 31.7 - 31.8 - 108.7 37.3 0.2 9.1 344.3 Industrial 0% 0.4 1.2 0.0% 0.0 1.78 - - 0.04 0.18 0.36 0.46 0.54 0.36 - - - - - - - - - - - High-density residential 77.9 46.5 60% 0.4 1.2 54.1% 42.1 2.32 97.8 16.0 11.2 2.9 1.3 31.4 0.04 0.18 0.36 0.46 0.54 0.36 0.6 2.0 1.1 - 0.7 - 4.4 4.4 0.1 0.6 102.8 Medium-density residential 386.9 167.0 43% 0.1 1.5 28.4% 109.7 1.96 215.1 90.4 29.3 77.5 22.7 219.9 0.04 0.18 0.36 0.46 0.54 0.36 3.6 5.3 27.9 - 12.2 - 49.0 57.3 0.2 12.8 276.9 Low-density residential 0% 0.1 1.5 0.0% 0.0 1.52 - - 0.04 0.18 0.36 0.46 0.54 0.36 - - - - - - - - - - - ROW 144.8 121.1 84% 0.1 1.5 76.6% 110.8 1.95 216.1 11.2 2.6 8.9 0.9 23.6 0.04 0.18 0.36 0.46 0.54 0.36 0.4 0.5 3.2 - 0.5 - 4.6 10.3 0.2 2.0 222.8 Forest 1343.6 0% 0.01 2 0.0% 0.0 1.52 - 633.5 173.4 340.9 195.8 1,343.6 0.11 0.14 0.19 0.21 0.23 0.19 69.7 24.3 64.8 - 45.0 - 203.8 - 0.2 - 203.8 Open land 152.9 22.3 15% 0.1 1.5 5.6% 8.5 1.52 13.0 34.7 67.9 17.0 11.0 130.5 0.04 0.18 0.36 0.46 0.54 0.36 1.4 12.2 6.1 - 5.9 - 25.7 13.8 0.2 2.7 41.3 Agriculture 25.2 0% 0.01 2 0.0% 0.0 1.52 - 0.9 18.6 0.1 5.6 25.2 0.07 0.29 0.60 0.76 0.91 0.60 0.1 5.4 0.0 - 5.1 - 10.6 - 0.4 - 10.6 Total 2,740.5 521.6 19% 15% 398.5 768.5 847.0 540.2 535.5 - 296.3 - 2,219.0 78.3 92.3 134.8 - 101.4 - 406.8 123.1 27.2 1,202.5 Fill in these cells Total Avg Annual Phosphorus Load (kg/yr) 545.5 EPA-provided values (Source: EPA Memorandum, Authored by: Mark Voorhees, Dated: 1/14/2014, Entitled: Overview of Methodology to Calculate Baseline Stormwater Phosphorus Loads and Phosphorus Load Reduction Requirements for Charles River)Baseline Load Increase (kg/yr) 15.5 Calculated values Approach 1 Calculations Total Avg Annual Phosphorus Load (lb/yr) Percent Impervious Sutherland Coeffs Percent Directly Connected Impervious Area (%) Directly Connected Impervious Area (ac) Phosphorus Loading Export Rate (lb/ac/yr) Avg Annual Phosphorus Export Load (lb/yr) Perv HSG Area (ac) Phosphorus Export Loading Rate (lb/ac/yr) Avg Annual Phosphorus Export Load (lb/yr)Phosphorus Land Use Group Total Area (ac) Impervious Area (ac) Directly Connected Impervious Area Pervious Area Phosphorus Load Disconnected Impervious Area Disconnected Impervious Area (ac) Pervious Area Composite Phosphorus Export Loading Rate (lb/ac/yr) Avg Annual Phosphorus Load (lb/yr) NOTES: 1. This spreadsheet was developed by Brown and Caldwell to calculate baseline phosphorus loads in accordance with the methodology used in the Massachusetts Small MS4 General Permit. EPA documented the baseline phosphorus load calculations in the EPA Memornadum authored by Mark Voorhess and dated 1/14/2014. 2. Only edit the yellow cells. 3. Brown and Caldwell is providing this spreadsheet as a courtesy to third parties. Brown and Caldwell makes no guarantees or warranties about its accuracy. You are responsible for verying all calculations. If you identify any issues, please contact Matt Davis (see contact info below) 4. This spreadsheet is valid only for calculating baseline phosphorus loads. The calculation of current loads is performed using a different methodology and phosphorus export loading rates. 5. For a detailed discussion of how baseline phosphorus loads are calculated, please watch the recorded video from the Charles River Watershed Association Phopshorus Control Planning Workshop #1 that was held on 3/8/2022. 6. Please contact Matt Davis at Brown and Caldwell if you have any questions. Email: mdavis@brwncald.com. Baseline Load Update June 2023 Commercial Industrial High Density Residential (HDR) Medium Density Residential (MDR) Low Density Residential (LDR) Highway Open Land Agriculture Forest Total Commercial Industrial High Density Residential (HDR) Medium Density Residential (MDR) Low Density Residential (LDR) Highway Open Land Agriculture Forest Total 255.8 43.3 116.1 477.9 251.8 3.0 111.3 102.0 1370.9 2732.1 609.3 0.0 77.9 386.9 0.0 144.8 152.9 25.2 1343.6 2740.5 Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 140.5 25.4 43.1 135.4 63.2 1.4 10.1 8.2 32.3 459.7 164.6 0.0 46.5 167.0 0.0 121.1 22.3 0.0 0.0 521.6 Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 115.3 17.9 72.9 342.5 188.6 1.6 101.3 93.7 1338.5 2272.4 444.7 0.0 31.4 219.9 0.0 23.6 130.5 25.2 1343.6 2219.0 Step 1: Estimate % Increase in Impervious Area (2005-2016) Increase in Impervious:61.9 % Increase in Impervious:13.5% Step 2: Increase 2005 Impervious Area Breakdown by Land Use by % Increase in Impervious Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 159.4 28.9 49.0 153.6 71.7 1.6 11.4 9.3 36.7 521.6 Step 3: Multiply Step 2 results by respective phosphorus load export rate (PLER) Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 33.7 6.1 13.5 35.7 12.9 0.3 2.1 1.7 6.6 112.5 Step 4: Estimate projected % Increase in Impervious Area (2005-2023) Increase in Impervious:61.9 % Increase in Impervious:19.6% Step 5: Repeat Step 2 & 3 for 2005-2023 Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 168.0 30.4 51.6 161.9 75.6 1.7 12.0 9.8 38.7 549.7 Commercial Industrial HDR MDR LDR Highway Open Land Agriculture Forest Total 49.0 8.9 19.6 52.0 18.8 0.4 3.0 2.4 9.6 163.7 2005 Impervious Area + 19.6% Increase to 2021 (acres) 2021 Impervious PLER Increase (TP lb/yr) Approach 2 Calculations Impervious Area (acres) Pervious Area (acres)Pervious Area (acres) 2005 Impervious Area + 13.5% Increase to 2016 (acres) 2016 Impervious PLER Increase (TP lb/yr) Municipal Only (less DOT and DCR) Impervious Area of aggregate land use categories in the Charles River Watershed, acres (ac)Municipal Only (less DOT and DCR) Impervious Area of aggregate land use categories in the Charles River Watershed, acres (ac) From Mark Vorhees Spreadsheet - 2005 From W&C - 2016 Total Area Total Area Impervious Area (acres) Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX C: FUNDING SOURCE ASSESSMENT 40 Shattuck Road | Suite 110 Andover, Massachusetts 01810 www.woodardcurran.com T 800.426.4262 T 978.557.8150 F 978.557.7948 MEMORANDUM TO: Town of Lexington, MA FROM: Woodard & Curran DATE: June 13, 2023 RE: Lexington, MA - Stormwater Funding Opportunities The purpose of this memorandum is to provide an overview of the potential funding opportunities available to the Town of Lexington, Massachusetts (Town). These funding programs come from both the federal and state level. The opportunities outlined in this document are focused on programs to help remove/mitigate nutrients from stormwater that pollute waterways. While this is not an exhaustive list of funding opportunities, this memorandum provides a starting point to evaluate the Town’s eligibility for external funding and a basis for the “Funding Source Assessment” required for inclusion in the Town’s Phase 1 Phosphorus Control Plan (PCP) by the 2016 MS4 General Permit. Massachusetts Clean Water State Revolving Fund Loan The Massachusetts State Revolving Fund (SRF) Loan programs provide state- subsidized, low-interest loans to finance local water quality protection and improvement projects. Among the financial programs listed here, the Clean Water State Revolving Fund (CWSRF) is the clear front-runner in terms of available and accessible financing for stormwater management. CWSRF projects are selected annually using a priority ranking system and are listed on the Massachusetts Department of Environmental Protection (MassDEP) website as the Intended Use Plan (IUP). IUP rankings are based upon protection of public health and improved compliance together with affordability. In 2023, MassDEP had approximately $900 million available to finance clean water projects. CWSRF Financing: Financing is available for the planning and construction of projects including: Measures to manage, reduce, treat, or recapture stormwater and surface drainage water; Stormwater Management Planning projects that help communities comply with the 2016 MS4 General Permit; and Development and implementation of conservation and management plans. Lexington, MA (0227871.12) 2 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 Timeline: (Annual process for 2024 Intended Use Plan): Project Evaluation Forms (PEFs) due mid-August 2023; Intended Use Plan issued in January 2024; Local Borrowing Authorization issued by end of June 2024; and SRF Application for Financial Assistance due mid-October 2024. Loan Terms: (Projects on 2023 Intended Use Plan): Loan Type Permanent Financing Interim Financing Standard SRF Loan 2% (20 years) 2.4% - 2.9% (30 years)0% Housing Choice Loan Rate 1.5% (20 years)0% Nutrient Enrichment Reduction Loan 0%0% Maximum Term 30 years 3 years Administrative Fee 0.15%0% Loan Origination Fee $5.50 per $1,000 $0 Massachusetts Municipal Vulnerability Preparedness Grants The Municipal Vulnerability Preparedness (MVP) Planning Grant offers funding to municipalities that wish to assess their vulnerability to, and prepare for, climate change impacts, build community resilience, and receive designation from the Executive Office of Energy and Environmental Affairs (EEA) as a Climate Change MVP program municipality. Responses to the Request for Responses (RFR) for communities may be submitted by any Massachusetts municipality or groups of municipalities. Municipalities with no current local hazard mitigation plan (HMP), or those with plans expiring in 2023 or 2024 (MVP plans are good for 5 years) are eligible for additional funding to complete or update a full draft of the HMP for Massachusetts Emergency Management Agency (MEMA) review. Lexington, Massachusetts is a Designated MVP Community and eligible to submit MVP Action Grants. MVP Action Grant The MVP Action Grant offers financial resources to municipalities that are seeking to advance priority climate adaptation actions to address climate change impacts resulting from extreme weather, sea level rise, inland and coastal flooding, severe heat, and more. Eligible applicants are municipalities who have completed the Community Resilience Building process and received “MVP Community” designation by EEA. Ap Lexington, MA (0227871.12) 3 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 plications from regional partnerships of multiple municipalities are eligible provided that the lead applicant is an MVP designated community. These grants are not solicited annually, but periodically. No solicitation is expected in 2023. Eligible projects must address one (or more) priority implementation actions within the municipality’s MVP plan/report and use the best available techniques and climate projections. Project types include: Detailed Vulnerability and Risk Assessment: In-depth vulnerability or risk assessment of a particular sector, location, or other aspect of the municipality. Community Outreach and Education: Projects that increase public understanding of climate change impacts within and beyond the community and foster effective partnerships to develop support. Local Bylaws, Ordinances, Plans, and other Management Measures: Projects to develop, amend, and implement local ordinances, bylaws, standards, plans, and other management measures to reduce risk and damages from extreme weather, heat, flooding, and other climate change impacts. Redesigns and Retrofits: Engineering and construction projects to redesign, plan, or retrofit vulnerable community facilities and infrastructure (e.g., wastewater treatment plants, culverts, and critical municipal roadways/evacuation routes) to function properly over the life of the infrastructure given projected climate change impacts. Energy Resilience Strategies: Projects that incorporate clean energy and are paired with resilience enabling technologies such as energy storage, energy management systems, black start, and islanding technologies at facilities for which the loss of electrical and/or heating and cooling services would result in disruption of critical functionalities that would put the health and safety of the surrounding community at risk (e.g., water and wastewater treatment facilities, emergency personnel dispatch, facilities which support municipal emergency operations, health services facilities, perishable grocery and pharmaceutical distribution facilities, and fuel facilities). Chemical Safety & Climate Vulnerabilities: Projects that engage the business and manufacturing community through assistance or training on identifying vulnerabilities to chemical releases due to severe weather events, reducing use of toxic or hazardous chemicals, improving operations and maintenance procedures to prevent chemical releases and accidents, improving emergency and contingency planning, and/or identifying existing contaminated sites that pose chemical dispersion risks during flood events. Nature-Based Flood Protection, Drought Prevention, Water Quality, and Water Infiltration Techniques: Green infrastructure projects that utilize natural resources and pervious surfaces to manage coastal and inland flooding, erosion, and other storm damage, such as stormwater wetlands (i.e., constructed wetlands for pollutant removal) and bioretention systems, and other Smart Growth and Low Impact Development techniques. Lexington, MA (0227871.12) 4 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 Nature-Based Infrastructure and Technology Solutions to Reduce Vulnerability to Extreme Heat and Poor Air Quality: Green infrastructure projects that utilize natural resources, vegetation, and increasing pervious surface to reduce ambient temperatures, provide shade, increase evapotranspiration, improve local air quality, and otherwise provide cooling services within the municipality. Nature-Based Solutions to Reduce Vulnerability to other Climate Change Impacts: Nature-based projects that address other impacts of climate change such as extreme weather, damaging wind and power outages, increased incidence of pests and vector-borne illnesses and other public health issues, and increases in forest pests. Acquisition of Land to Achieve a Resiliency Objective: Land purchases that have been identified through a climate vulnerability assessment as an appropriate location for a specific eligible adaptation activity to occur, such as accommodating an infrastructure or facility redesign or retrofit project, providing natural flood storage to reduce downstream flooding, or removal of pavement and planting of trees to reduce flooding and heat island effects. Land purchases on which a specific nature-based solution will be employed, such as a constructed wetland, bioretention system, or living shoreline, are eligible, as are land purchases that preclude growth in a vulnerable location (e.g., a park instead of development in a floodplain whether construction is legal, but not prudent as it would put lives and property at risk or in high fire-prone areas like pitch pine barren areas). Ecological Restoration and Habitat Management to Increase Resiliency: Projects that repair or improve degraded natural resources or infrastructure within a municipality to enhance resilience and adapt to climate change, such as resizing culverts, dam removal, controlled burns, soil stabilization, invasive species removal and native revegetation, prevention and recovery from forest pest invasions in urban and rural forests, restoration of land for flood control, and other natural resource management projects. For infrastructure redesigns and retrofits, implementation of nature-based solutions, or ecological restoration and habitat management projects, projects must address one (or more) of the following stages of implementation: Planning, feasibility assessment, and siting; Design; Permitting; and/or Construction, installation, and monitoring. Funding: Funding amounts are expected to range from $25,000 to $2 million. Regional projects may request up to $5 million. A minimum 25% match of the total project cost is required. Lexington, MA (0227871.12) 5 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 Timeline: Applications are accepted at least once per year. Next round expected in June 2024. MassDEP: Section 604b Water Quality Management Planning Grant Program The Massachusetts Department of Environmental Protection administers the Section 604b Water Quality Management Planning Grants. For Federal Fiscal Year (FFY) 2023, approximately $165,000 will be available. Eligible entities include regional planning agencies, council of governments, counties, conservation districts, and cities and towns. Eligible projects are nonpoint source assessment and planning projects that result in the following: Development of Watershed-based Plans (“WBPs”) for local watershed planning and to support future Section 19 grant projects; Determination of the nature, extent, and causes of water quality problems, and determination of pollutant load reductions necessary to meet water quality standards; Development of green infrastructure projects that manage wet weather events to maintain or restore natural hydrology; or Development of preliminary designs and implementation plans that will address water quality impairments in impaired watersheds. Priority will be given to the following types of projects: development of Watershed- based Plans, water quality assessments, green infrastructure and low impact development, and development of implementation plans. Grant awards typically range between $30,000 to $50,000 range. A match is not required but is highly encouraged. Coastal Habitat and Water Quality Grants Contracting Entity: Massachusetts Office of Coastal Management Type: Grant Awards up to $125,000. In FY 2022, the State funded three projects totaling $181K all in communities with direct coastal access. Match: 25% Eligible Applicants: The Coastal Pollutant Remediation (CPR) Grant Program is open to municipalities located within the boundaries of the Massachusetts coastal watershed, which encompasses 220 cities and towns in eastern Massachusetts, including the Town of Lexington. Eligible Projects: 1. Assessment, identification, and characterization of Non-Point Source (NPS) Pollution Assessment efforts can include the identification of non-point source pollution and offer recommendations for controlling or eliminating these sources. Such projects can include the analysis of historical water quality data, physical assessment of drainage areas, land use characterization, water quality testing at in- Lexington, MA (0227871.12) 6 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 stream and outfall locations, and the development of recommendations for NPS management (structural and non-structural), as well as the investigation of the appropriate type and placement of stormwater control measures (SCMs). 2. Design and/or implementation of: a) SCMs to remediate runoff from paved or unpaved roads, highways, bridges, and municipal parking lots; or b) Commercial boat-waste pump out facilities. Due Date: Annual – Next Round of Applications expected in June 2023. Link: Coastal Habitat and Water Quality Grants | Mass.gov Funding: Approximately $2 million was available for FFY 2023. A 40% non-federal match is required. Timeline: Applications are accepted annually and expected to be due in the beginning of June 2023 Massachusetts Division of Ecological Restoration: Restoration & Revitalization Priority Projects Program The Massachusetts Division of Ecological Restoration (DER) administers the Restoration and Revitalization Priority Projects Program to restore and protect the Commonwealth’s rivers, wetlands, and watersheds for the benefit of people and the environment, specifically streamflow restoration and urban stream revitalization. Eligible applicants include restoration project site landowners, non-profit and/or non- governmental organizations, regional planning organizations, municipalities, and state and federal agencies. Eligible projects are defined by the following categories: Streamflow restoration projects including: o Development of water management plans to restore more natural streamflow regimes (e.g., management of dams on recreational lakes and drinking water reservoirs); o Use of water conservation methods to reduce water consumption and withdrawals (e.g., development of campaigns to reduce residential outdoor water use); o Exploration of alternative local water supplies to minimize flow stress in specific stream reaches; and proposed innovative methods to document and address stream flow issues including low flow, no flow, or altered flow regimes that impact biota and water quality; and o Stand-alone dam removal/culvert/tidal projects do not fit under this category but may be proposed if they are part of a larger streamflow restoration project. Urban stream and river revitalization projects including: o Creation of natural vegetated buffers in urban riparian corridors; Lexington, MA (0227871.12) 7 Woodard & Curran, Inc. Stormwater Funding Opportunities June 13, 2023 o Naturalization of stream form and habitat; o Improvement of water quality; o Daylighting stream reaches that have been buried underground; o Improvement to connections between local communities and their rivers via new access points and educational opportunities; and o Proposed innovative methods to improve ecological conditions and services of streams and wetlands and public access in urban settings or areas with limited access to open space. Preference will be given to projects that utilize proven approaches, are part of a larger restoration/revitalization plan, address root causes of impairment over symptoms, result in implementation of actions that deliver significant restoration benefits, and achieve a self-sustaining long-term restoration trajectory with minimal ongoing maintenance. The value of technical services and/or funding typically ranges between $10,000 to $70,000. A match is not required. Next round expected in June 2024. For more information, click here. Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX D: EXISTING NON-STRUCTURAL CONTROL CREDIT CALCUATIONS CLIENT:Town of Lexington, Massachusetts PROJECT:Phosphorus Control Plan DESIGNED BY:LFE DATE:5/26/2023 CHECKED BY:DATE: PROJECT NO.227871.12 40 Shattuck Road, Suite 110 Andover, MA 01810 Tel: 978.557.8150 Fax: 978.557.7948 Phosphorus Load Reduction (lbs/year) Enhanced Sweeping 15-45B 9 PHILIP RD Commercial/Industrial 1.78 2.8 0.05 15-68 PHILIP RD Commercial/Industrial 1.78 0.2 0.00 24-83A 3 STEDMAN RD Commercial/Industrial 1.78 0.3 0.00 31-63D 39 MARRETT RD Commercial/Industrial 1.78 1.1 0.02 31-65A 20 PELHAM RD Commercial/Industrial 1.78 1.2 0.02 32-177C 17 STEDMAN RD Commercial/Industrial 1.78 1.7 0.03 51-45A 7 CROSBY RD Commercial/Industrial 1.78 3.1 0.05 Net Reduction (lbs/year)0.18 Phosphorus Load Reduction (lbs/year) Enhanced Sweeping 1.95 88.2 1.72 Net Reduction (lbs/year)1.72 Total Net Reduction (lbs/year)1.90 NOTES: 1. Enhanced sweeping credit: Appendix F requirements are met for 2x/year sweeping using a mechanical broom sweeper. Entire paved area (driveways, parking lots, sidewalks, patios, etc.) is swept Paved Area (ac) Town-Owned Non-Structural Phosphorus Reduction Analysis - Current Credit Policy Parcel ID Location MassGIS Parcel Land Use Desc. (2016) Right-of-Way Town-Owned Parcels MassGIS Land Use (2016)Export Rate (lbs/ac/year) Export Rate (lbs/ac/year) Roadway Area (ac) Town-Owned Roadway Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX E: EXISTING STRUCTURAL CONTROLS E.1: Credit Calculations E.2: Fact Sheets E.3: SCM Location Figures Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 E.1: Credit Calculations CLIENT:Town of Lexington, MassachusettsPROJECT:Phosphorus Control Plan40 Shattuck Road, Suite 110DESIGNED BY:LFEDATE:5/30/2023Andover, MA 01810CHECKED BY:DATE:Tel: 978.557.8150 Fax: 978.557.7948PROJECT NO.227871.12Property Application Date Parcel ID Address Municipal/Private Facility Land Use BMP TypeSoil Infiltration Rate (in/hr)Impervious Drainage Area (AC)Pervious Drainage Area (AC)Pervious Drainage Area Soil TypeBMP Storage Volume (cf)BATT Reduction (lbs/year)BATT Total Property Reduction (lbs/year)BMP ID (MGT#)2022 BMP Field Verification? (Y/N)If N, why?Bioretention-0.270.18C6790.24MGT 150YInfiltration Chambers2.410.480.88C8910.90MGT 148YInfiltration Chambers2.410.771.08C2,7501.56MGT 146Y12/12/200739-1010 Pelham RdPrivateApartmentsCommerical-----------Dry Well1.020.05--280.03MGT 305YVegetated filter strip1.020.35---0.20MGT123Y6/6/201143-9D3 Forbes RdPrivateOfficesCommerical-----------39/2/202218-2B99 Hayden AvePrivateOfficesCommericalInfiltration Chambers - Not Yet Constructed------4.55---46/28/200651-56A727 Marrett RdPrivateHotelCommericalConstructed Wetlands1.024.07--14,7743.843.84MGT 286YInfiltration Chambers0.171.17--1,6121.14MGT 333YInfiltration Basin0.170.35--4210.41MGT 329NNo site plans during site visit. 2/3/201018-15F200 Shire WayPrivateOfficesCommerical/Industrial-----------PrivateInfiltration Chambers2.410.81--13,8091.421.42MGT 273Y8/1/200718-4A92 Hayden AvePrivateOfficesCommerical/Industrial-----------2/2/201652-8BInfiltration trenches - Outside Town Line2.410.94-------6/2/201452-7BInfiltration trench (Underfield Storage)2.414.32--16,4006.45MGT 201Y9/10/2018 52-53022 Massachusetts Ave/752 Marrett RdPrivate Eversource Commerical/Industrial - - - - - - - - - - -6/12/200116-53H7 Clematis RdPrivateChurchCommerical/Industrial-----------4/19/201117-1980 Hayden AvePrivateOfficesCommerical/Industrial-----------84/2/20085-11A1075 Waltham StPrivateBankCommericalInfiltration Chambers1.020.120.01C4800.210.21MGT 279Y8/28/200942-54594 Marrett RdPrivateOfficesCommerical/Industrial-----------93/11/201332-16324 Marrett RdPrivateCumberland FarmsCommericalInfiltration Chambers2.410.14--4,3320.250.25MGT 282YInfiltration Chambers2.410.840.72B7,9751.56MGT 171YInfiltration Chambers2.410.200.08B1,7280.36MGT 140YBioretention - Infiltration Basin2.410.080.26B8520.17MGT 139YPorous Pavement-0.900.19B-0.82MGT 138YDetention Pond2.410.734.33A8,6050.20MGT 141YInfiltration Chambers1.021.240.10C4,5912.14MGT 187Y1.39A0.64CInfiltration Chambers1.020.820.16C3,1141.44MGT 183YBioretention - Infiltration Basin2.410.501.87A1,7650.92MGT 188YBioretention - Infiltration Basin1.020.330.70C1,7070.72MGT 190YBioretention - Infiltration Basin1.020.090.78C1,5190.31MGT 189YPorous Pavement-0.930.12C-0.84MGT 205YInfiltration Chambers1.021.946--5,5503.17MGT 302NUnder construction.Permeable Pavement1.02-0.34D-----Infiltration Pond0.17-0.18D2,525----Infiltration Chambers1.020.780.33B1,4121.13MGT 268YInfiltration Chambers0.270.320.04B5800.41MGT 269Y4/5/20053-1A75 Concord AvePrivateCommunication towerCommerical/Industrial----------Infiltration Chambers2.411.47--3,2902.39MGT 264NUnder construction. Infiltration Chambers2.412.05--5,1703.41MGT 267NOvergrown. Unable to confirm location. Infiltration Chambers0.521.17--2,1151.56MGT 306Y4.12C15.97D4/1/201143-128A/B690 Marrett/Route 128StateMcDonalds/Gas StationCommerical/IndustrialDry Pond - State Owned----------1510/2/201412-3187 Spring StPrivateTherapeutic Day SchoolCommericalInfiltration Chambers2.410.05--4750.090.09MGT 200Y16 7/30/1999 31-63D 39 Marrett Rd Municipal Community Center Commerical Infiltration Basin 2.41 1.14 - - 7,446 2.03 2.03MGT 322 N No site plans during site visit. Non-Residential Total Credit (lbs/year)55.79MunicipalMinuteman High SchoolNon-Residential Properties2.700.235,01615.10-Wet Pond2.041.081.021.546.453.128.413.171.5413 CommericalCotting School453 Concord AveCommericalOffices18-15D (300 Shire Way), 18-15F (200 Shire Way), 18-15G (400 Shire Way)8/12/201918-15D/F/G4/11/200814Infiltration ChambersLab/Offices Commerical/Industrial7/29/202020 Pelham RdOpen Land5-14756-758 Marrett Rd11/15/201710-62332 Concord AveChildcarePrivatePrivateCommerical11School Commerical31-65A1 32-177CJonas Clarke Middle School - LexingtonCommerical17 Stedman Rd10 12/28/2017715-45BBowman Elementary School5/9/2016 9 Philip Rd Commerical2CommericalOffices45-55 Hayden Ave17-21A-112/21/20152/12/2015565/8/2017YMGT 265 YMGT 18251-45A 7 Crosby Rd School Commerical1050 Waltham10-41A13,661 8.9016.2612MunicipalPrivatePrivateMunicipalMunicipalPrivate1 of 3 CLIENT: Town of Lexington, MassachusettsPROJECT: Phosphorus Control Plan40 Shattuck Road, Suite 110 DESIGNED BY: LFE DATE: 5/30/2023Andover, MA 01810 CHECKED BY: DATE:Tel: 978.557.8150 Fax: 978.557.7948 PROJECT NO. 227871.12Property Application Date Parcel ID Address Municipal/Private Facility Land Use BMP TypeSoil Infiltration Rate (in/hr)Impervious Drainage Area (AC)Pervious Drainage Area (AC)Pervious Drainage Area Soil TypeBMP Storage Volume (cf)BATT Reduction (lbs/year)BATT Total Property Reduction (lbs/year)BMP ID (MGT#)2022 BMP Field Verification? (Y/N)If N, why?Infiltration Chambers #11.020.17--3,2690.38MGT 293Y0.65B0.28DInfiltration Chambers #31.020.32--1,8540.74MGT 294YInfiltration Chambers #40.170.07--8500.15MGT 295YInfiltration Basin North (#5)1.020.30--2,1010.70MGT 296Y0.14B0.19DInfiltration Chambers #70.170.18--1,6080.38MGT 298Y0.20B0.13D0.65B0.28D8/15/2007Wet Detention Basin 2007-0.281.10C5030.36MGT 330YInfiltration Chambers1.952.512.06A4,5604.94MGT 331NUnder construction. Green Roof--------Extended Dry Detention-0.321.53A5750.07MGT 332NUnder construction.Infiltration Chambers 12.410.970.71A3,5132.23MGT 217YInfiltration Chambers 21.020.380.92A3,4060.88MGT 219YInfiltration Chambers 31.020.441.38A7910.84MGT 216YBioretention/Infiltration Basin 11.020.050.05A1570.11MGT 215YBioretention/Infiltration Basin 22.410.060.03A2260.14MGT 214YBioretention/Infiltration Basin 31.020.120.35A2180.25MGT 218Y3/1/201850-2345 Lincoln StPrivateSingle FamilyMedium-Density Residential-----------46/4/201324-7A62 Grassland StPrivateSingle FamilyMedium-Density ResidentialImpervious Area Removal0.170.01---0.020.02MGT 211Y511/3/202024-5G72 Grassland StPrivateSingle Family Single Family ResidentialInfiltration Chambers1.020.030.16B4500.080.08MGT 212NCould not access backyard. 5/22/201587-11151 Grove StPrivateSingle FamilySingle Family Residential-----------69/23/20089-8310 Concord AvePrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers2.410.00--620.010.01MGT 213YInfiltration Chambers2.410.22--1,6250.50MGT 210YInfiltration Basin2.410.34--3,2550.78MGT 209Y5/14/201225-18 Cutler Farm RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers8.270.06--4490.12MGT 225Y5/14/201225-18 Cutler Farm RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Trench8.270.02--2400.05MGT 224Y94/6/200625-613 Cutler Farm RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers2.410.02--2550.040.04MGT 226Y104/30/200825-414 Cutler Farm RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers2.000.06--4030.120.12MGT 227Y1111/9/201542-218116 School StPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers0.270.11--9320.200.20MGT 245YInfiltration Chambers8.270.030.00-1760.05MGT 236YInfiltration Chambers8.270.020.00-1040.03MGT 237Y5.760.020.00-1570.03MGT 220Y5.760.010.00-900.01MGT 221Y5.760.050.09B6310.09MGT 222Y3/7/20139-105C19 Wellington LnPrivateSingle Family------------149/6/200517-159 Woodcliffe RdPrivateSingle FamilyLow-Density ResidentialInfiltration Chambers0.500.050.00-2690.070.07MGT 223NCould not access backyard. Fenced. 11/7/200811-6231 Barberry RdPrivateSingle Family------------11/7/200811-6133 Barberry RdPrivateSingle Family------------151/27/200624-47B66 Valleyfield StPrivateSingle FamilyLow-Density ResidentialSubsurface Infiltration Trench0.500.050.00-610.040.04MGT 246NCould not access backyard. Fenced. 164/18/201325-84A65 Munroe RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers0.500.060.00-4710.110.11MGT 242 Y 173/25/201417-1866 Munroe RdPrivateSingle FamilyMedium-Density ResidentialInfiltration Chambers5.980.050.00-5800.100.10MGT 241YInfiltration Chambers0.520.080.08C7570.160.16MGT 239YInfiltration Chambers0.520.010.02C2440.020.02MGT 238Y1/16/200610-15 Stonewall RdPrivateSingle FamilyLow-Density ResidentialProposed Pervious Pavers----------10-37C 411 Concord Ave Private Single Family - - - - - - - -- - -19 5/22/2012 11-47 470 Concord Ave Private Single Family Low-Density Residential Infiltration Chambers 8.27 0.05 - - 3580.07 0.07 MGT 240 Y20 6/9/2015 17-17 60 Munroe Rd Private Single Family Medium-Density Residential Infiltration Chambers 0.17 0.08 - - 445 0.16 0.16 MGT 243 Y1.02Infiltration Basin West37 Barberry Rd Single Family33 Dawes Rd4218964.441.280.160.070.142.010.460.725.00Infiltration Chambers #22,79013PrivateHigh Density ResidentialAssisted Living53-55 Watertown St3-157/17/2017Independed Living High Density Residential 1.0535-2Single Family6/10/2008MGT 2922/20/2018YMGT 297 YMGT 2914/12/2019YMGT 290 Y56 Watertown St Assisted Living960-1010 Waltham5-20; 5-21A4/30/2019High Density Residential1.066.950.370.558Infiltration Chambers10 Philip Rd Single Family Medium-Density Residential18 11/26/2014 15-67B5/17/2005 11-59 Low-Density Residential23-13-16Low-Density ResidentialHigh Density ResidentialCondos443 Lincoln St (Hobbs Brook Ln)Residential Properties1.020.17Infiltration Chambers #60.411.02712123Infiltration Basin East 181PrivatePrivatePrivatePrivatePrivatePrivate2 of 3 CLIENT: Town of Lexington, MassachusettsPROJECT: Phosphorus Control Plan40 Shattuck Road, Suite 110 DESIGNED BY: LFE DATE: 5/30/2023Andover, MA 01810 CHECKED BY: DATE:Tel: 978.557.8150 Fax: 978.557.7948 PROJECT NO. 227871.12Property Application Date Parcel ID Address Municipal/Private Facility Land Use BMP TypeSoil Infiltration Rate (in/hr)Impervious Drainage Area (AC)Pervious Drainage Area (AC)Pervious Drainage Area Soil TypeBMP Storage Volume (cf)BATT Reduction (lbs/year)BATT Total Property Reduction (lbs/year)BMP ID (MGT#)BMP Field Verification? (Y/N)If N, why?Infiltration Chambers 2.41 0.09 - - 549 0.17 0.17 MGT 232 YInfiltration Chambers 2.41 0.06 - - 384 0.13 0.13 MGt 233 Y22 9/22/2010 24-1 71 Bridge St Private Single Family Medium-Density Residential Dry well 0.00 - - 156 0.01 0.01 MGT 247 Y8/10/2010 24-8910 Stedman (32 Brookside Ave)Private Single Family - - - - - - - - - - - -Infiltration Chambers 2.41 0.01 - - 114 0.02 MGT 228 YInfiltration Trench 2.41 0.01 - - 75 0.02 MGT 229 YInfiltration Chambers 1.02 0.02 - - 808 0.04 MGT 230 N Unable to communicate with resident. Could not access.Infiltration Chambers 1.02 0.04 - - 708 0.08 MGT 325 N Unable to communicate with resident. Could not access.10/26/2010 25-230 10 Winston Private Single Family - - - - - - -- - - - -Infiltration Chambers 2.41 0.02 - - 149 0.04 MGT 234 YInfiltration Trench 2.41 0.02 - - 36 0.03 MGT 326 N Could not access backyard. 5/11/2010 31-89A 2 Paddock Ln Private Single Family - - - - - - -- - - - -4/7/2015 9-18 6 Blossom St Private Single Family - - - - - - - - - -- -Infiltration Chambers 5.98 0.04 - - 230 0.07 MGT 248 YInfiltration Chambers 5.98 0.03 - - 259 0.06 MGT 327 N Could not access backyard. 27 1/7/2005 34-63 26 Middle St Private Single Family Medium-Density Residential Infiltration Chambers 2.41 0.03 - - 220 0.06 0.06 MGT 253 Y28 11/5/2008 34-78 64 Middle St Private Single Family Medium-Density Residential Infiltration Chambers 1.02 0.01 - - 13 0.01 0.01 MGT 259 Y2/13/2009 8-64 3 Crescent Rd Private Single Family - - - - - - - -- - - -Infiltration Chambers8.270.03--1800.05MGT 252YInfiltration Trench8.240.01--2200.02MGT 251Y34-47A 31 Cary Ave Private Infiltration Chambers 0.17 0.053- - 95 0.07 MGT 256 Y34-47B 33 Cary Ave Private Infiltration Chambers 0.17 0.065- - 117 0.08 MGT 255 Y34-47E 35 Cary Ave Private Infiltration Chambers 0.17 0.051- - 92 0.07 MGT 254 Y34-48C Cary Ave Private Detention Basin - 0.142 - - 516 0.03 MGT 328 N No site plans during site visit. Infiltration Chambers 1.02 0.017 - - 251 0.03 MGT 257 YInfiltration Chambers 1.02 0.021 - - 375 0.04 MGT 258 N Could not access backyard. Fenced. Infiltration Chambers 8.27 0.10 - - 359 0.23 MGT 284 YInfiltration Chambers2.410.43--1,5530.97MGT 285YLeaching CB2.410.05--1780.11MGT 323YExfiltrating Bioretention - Infiltration Basin1.020.291.78C2,7141.01MGT 263YExfiltrating Bioretention - Infiltration Basin1.020.682.64C4,3102.13MGT 262YInfiltration Chambers2.410.910.38B12,3262.12MGT 270YInfiltration Chambers2.410.580.67B9,6721.41MGT 271NCould not access backyard. Fenced. Wetland Replication-2.054.89B1,1241.05MGT 324NCould not access backyard. Fenced. Infiltration Chambers2.410.38-2,0790.89MGT 277YInfiltration Chambers2.410.08-6130.19MGT 275YInfiltration Chambers 2.41 0.08 - 493 0.20 MGT 274 YInfiltration Basin 2.41 9.34 - 9,057 15.98 MGT 276 YMultiple Retention North- Outlet at pond bottom - 0 0.00 0.00 - - -MultipleRetention South - Outlet at pond bottom- 0 0.00 0.00 - - -37 Dry Wells 2.41 0.44 - - 1,871 0.85 MGT 307-MGT 320 Y38 Infiltration Chambers 2.41 0.35 0.23 A 1,122 0.67 MGT 45Y39 1/10/2022 34-66 32 Middle St Private Single Family Medium-Density Residential Infiltration Chambers 2.41 0.05 - - 762 0.10 0.10 MGT 321 YResidential Total Credit (lbs/year) 48.25Non-Residential Total Credit (lbs/year) 55.79Total Credit (lbs/year) 104.0523.09 MultipleHigh Density ResidentialApartments1000 Main Campus Dr1-3Medium-Density ResidentialCondosGrey Oaks Cir35-3A5/24/2016PrivatePrivate2/8/2005Single Family Medium-Density ResidentialPrivatePrivaePrivatePrivatePrivatePrivate30 12/2/2008 Single Family Medium-Density Residential 0.251.520.030.120.070.130.071.313.144.5817.250.0721Low-Density Residential1/4/2016 23-19 10 Churchill Ln Single Family Medium-Density ResidentialResidential PropertiesPrivatePrivate32 3/30/2009 33-264A 341 Marrett Rd Condos High Density Residential24-952/25/201426 11/19/2013 34-57 14 Middle St29 7/28/2006 34-50 17 Cary Ave Single Family Low-Density ResidentialMedium-Density ResidentialSingle Family2 Brookside Ave2524Medium-Density ResidentialSingle Family114 Marrett Rd31-5111/16/201035High Density ResidentialCondos High Density Residential8.5936 5/14/1986 33-273 24 Valleyfield St Subdivision34 10-8-1 430 Concord Ave Assisted Living12/12/201833 12/15/2008 26-44F Journeys End Ln PrivatePrivatePrivate31 1/18/2018 34-41A 55 Cary Ave Single Family Medium-Density ResidentialSingle Family12 Brookside Ave24-938/5/2015233 of 3 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 E.2: Fact Sheets 1 BMP Fact Sheets Non-Residential Properties 2 BMP Location Address: 17 Stedman Road Parcel ID: 32-177C BMP ID: MGT 150 Property Type: ☐ Residential ☒ Non-residential Facility: Jonas Clarke Middle School Approximate BMP Coordinates Latitude: 42.43101844°N Longitude: -71.22967957°W Phosphorus Reduction Credit BMP Type: Bioretention Drainage Area: Land Use: Commercial Impervious Area (acres): 0.27 Directly Connected Impervious Area (acres): 0.24 Pervious Area (acres): 0.19 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.24 Maintenance and Inspection BMP Permit/Construction Date: January 11, 2016 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 18, 2022 (Inspection ID: INSP-86-SWBMP, Inspector: AET) Notes Permit Number: 201-1014 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Bioretention area overgrown. Trash observed within bioretention area. Photo(s) of Existing BMP BMP Verification Date: April 20, 2022 3 BMP Location Address: 17 Stedman Road Parcel ID: 32-177C BMP ID: MGT 148 Property Type: ☐ Residential ☒ Non-residential Facility: Jonas Clarke Middle School Approximate BMP Coordinates: Latitude: 42.43121443°N Longitude: -71.22995584°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 0.48 Directly Connected Impervious Area (acres): 0.45 Pervious Area (acres): 0.89 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.90 Maintenance and Inspection BMP Permit/Construction Date: January 11, 2016 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 18, 2022 (Inspection ID: INSP-86-SWBMP, Inspector: AET) Notes Permit Number: 201-1014 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Infiltration trench surface grate is in good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 4 BMP Location Address: 17 Stedman Road Parcel ID: 32-177C BMP ID: MGT 146 Property Type: ☐ Residential ☒ Non-residential Facility: Jonas Clarke Middle School Approximate BMP Coordinates: Latitude: 42.43016122°N Longitude: -71.22994511°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 0.77 Directly Connected Impervious Area (acres): 0.60 Pervious Area (acres): 1.08 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 1.56 Maintenance and Inspection BMP Permit/Construction Date: January 11, 2016 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Mass Ave Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 18, 2022 (Inspection ID: INSP-91-SWBMP, Inspector: AET) Notes Permit Number: 201-1014 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface infiltration chamber. Inlet grates in good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 5 BMP Location Address: 9 Philip Road Parcel ID: 15-45B BMP ID: MGT 305 Property Type: ☐ Residential ☒ Non-residential Facility: Bowman Elementary School Approximate Coordinates: Latitude: 42.423256°N Longitude: -71.219200°W Phosphorus Reduction Credit BMP Type: Dry well Drainage Area: Land Use: Commercial Impervious Area (acres): 0.05 Directly Connected Impervious Area (acres): 0.06 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: May 9, 2016 (Construction Date) Name of Owner: Town of Lexington Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1027 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 6 BMP Location Address: 9 Philip Road Parcel ID: 15-45B BMP ID: MGT 123 Property Type: ☐ Residential ☒ Non-residential Facility: Bowman Elementary School Approximate Coordinates: Latitude: 42.4238737°N Longitude: -71.21935512°W Phosphorus Reduction Credit BMP Type: Vegetated Filter Strip Drainage Area: Land Use: Commercial Impervious Area (acres): 0.35 Directly Connected Impervious Area (acres): 0.34 Pervious Area (acres): N/A Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.196 Maintenance and Inspection BMP Permit/Construction Date: May 9, 2016 (Construction Date) Name of Owner: Town of Lexington Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: June 24, 2020 (Inspector: Weston & Sampson) Notes: Permit Number: 201-1027 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Vegetated filter strip was likely destroyed/compacted during the construction of the solar panels in the adjacent parking lot or during winter plowing. Tiring rutting was observed along strip. Remove silt socks. Photo of Existing BMP BMP Verification Date: April 20, 2022 7 BMP Location Address: 727 Marrett Road Parcel ID: 51-56A BMP ID: MGT 286 Property Type: ☐ Residential ☒ Non-residential Facility: Hotel Approximate Coordinates: Latitude: 42.44455951°N Longitude: -71.25997744°W Phosphorus Reduction Credit BMP Type: Constructed Wetlands Drainage Area: Land Use: Commercial Impervious Area (acres): 4.07 Directly Connected Impervious Area (acres): 3.78 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 3.84 Maintenance and Inspection BMP Permit/Construction Date: September 22, 2006 (BMP Permit) Name of Owner: Lixi Hospitality Lexington, Inc. Owner Contact: 4545 Boulevard Cote-Vertu, H4S1CB, St. Laurent, Quebec Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-692 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Overgrown. Photo of Existing BMP BMP Verification Date: May 18, 2022 8 BMP Location Address: 45-55 Hayden Ave Parcel ID: 17-21A BMP ID: MGT 333 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.423855°N Longitude: -71.241242°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 1.17 Directly Connected Impervious Area (acres): 1.21 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 1.14 Maintenance and Inspection BMP Permit/Construction Date: February 14, 2017 (BMP Permit) Name of Owner: HCP Inc. c/o Lincoln Property Company Owner Contact: 200 Cambridge Park Drive Cambridge MA 02140 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1044 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 9 BMP Location BMP Observation Notes: No site plans during site visit. Address: 45-55 Hayden Ave Parcel ID: 17-21A BMP ID: MGT 329 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.423530°N Longitude: -71.243587°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 0.35 Directly Connected Impervious Area (acres): 0.33 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.41 Maintenance and Inspection BMP Permit/Construction Date: February 14, 2017 (BMP Permit) Name of Owner: HCP Inc. c/o Lincoln Property Company Owner Contact: 200 Cambridge Park Drive Cambridge MA 02140 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1044 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: N/A Photo of Existing BMP BMP Verification Date: N/A 10 BMP Location Address: 332 Concord Ave Parcel ID: 10-62 BMP ID: MGT 273 Property Type: ☐ Residential ☒ Non-residential Facility: Childcare (Goddard School) Approximate Coordinates: Latitude: 42.4173788 °N Longitude: -71.22899503°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.81 Directly Connected Impervious Area (acres): 0.81 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 1.42 Maintenance and Inspection BMP Permit/Construction Date: October 26, 2018 (BMP Permit) Name of Owner: Sun Tree Realty LLC Owner Contact: 332 Concord Ave, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 11 BMP Location Address: 756-758 Marrett Road Parcel ID: 52-7B & 52-8B BMP ID: MGT 201 Property Type: ☐ Residential ☒ Non-residential Facility: Minuteman High School Approximate Coordinates: Latitude: 42.44588616 °N Longitude: -71.27087701 °W Phosphorus Reduction Credit BMP Type: Infiltration Trench (Under field) Drainage Area: Land Use: Open Land Impervious Area (acres): 4.32 Directly Connected Impervious Area (acres): 4.32 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 6.45 Maintenance and Inspection BMP Permit/Construction Date: February 15, 2018 (BMP Permit) Name of Owner: SCHOOL Minuteman Voc School Owner Contact: 758 Marrett Road, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1062 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20, 2022 12 BMP Location Address: 1075 Waltham Street Parcel ID: 5-11A BMP ID: MGT 279 Property Type: ☐ Residential ☒ Non-residential Facility: Bank Approximate Coordinates: Latitude: 42.41345577 °N Longitude: -71.23305476 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.12 Directly Connected Impervious Area (acres): 0.12 Pervious Area (acres): 0.01 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.21 Maintenance and Inspection BMP Permit/Construction Date: November 14, 2007 (Construction Date) Name of Owner: Watertown Savings Bank Owner Contact: 60 Main Street, Watertown, MA 02472 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-637 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 13 BMP Location Address: 324 Marrett Road Parcel ID: 32-16 BMP ID: MGT 282 Property Type: ☐ Residential ☒ Non-residential Facility: Cumberland Farms Approximate Coordinates: Latitude: 42.43544418 °N Longitude: -71.23531641 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.14 Directly Connected Impervious Area (acres): 0.14 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.25 Maintenance and Inspection BMP Permit/Construction Date: March 11, 2013 Name of Owner: Cumberland Farms Inc Owner Contact: 165 Flanders Rd, Westborough, MA 01581 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 14 BMP Location Address: 20 Pelham Parcel ID: 31-65A BMP ID: MGT 171 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Children’s Place Approximate Coordinates: Latitude: 42.4372772 °N Longitude: -71.21891283 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.84 Directly Connected Impervious Area (acres): 0.62 Pervious Area (acres): 0.72 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 1.56 Maintenance and Inspection BMP Permit/Construction Date: June 18, 2018 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Massachusetts Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April, 20 2022 (Inspector: AET, Inspection ID: INSP-131-SWBMP) Notes: Permit Number: 201-1082 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Inlet free of debris. Photo of Existing BMP BMP Verification Date: April 20, 2022 15 BMP Location Address: 20 Pelham Parcel ID: 31-65A BMP ID: MGT 140 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Children’s Place Approximate Coordinates: Latitude: 42.43734768°N Longitude: -71.21723281°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.84 Directly Connected Impervious Area (acres): 0.17 Pervious Area (acres): 0.08 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.36 Maintenance and Inspection BMP Permit/Construction Date: June 18, 2018 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Massachusetts Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 18, 2022 (Inspector: AET, Inspection ID: INSP-125-SWBMP) Notes: Permit Number: 201-1082 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Remove silt sock blocking inlet to sediment separator that is routed to Recharger #2. Photo of Existing BMP BMP Verification Date: April 20, 2022 16 BMP Location Address: 20 Pelham Parcel ID: 31-65A BMP ID: MGT 139 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Children’s Place Approximate Coordinates: Latitude: 42.43798112°N Longitude: -71.21702628°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 0.08 Directly Connected Impervious Area (acres): 0.08 Pervious Area (acres): 0.27 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.17 Maintenance and Inspection BMP Permit/Construction Date: June 18, 2018 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Massachusetts Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 20, 2022 (Inspector: AET, Inspection ID: INSP-129-SWBMP) Notes: Permit Number: 201-1082 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Remove silt socks, construction sign knocked over into BMP area. Photo of Existing BMP BMP Verification Date: April 20, 2022 17 BMP Location Address: 20 Pelham Parcel ID: 31-65A BMP ID: MGT 138 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Children’s Place Approximate Coordinates: Latitude: 42.4376545°N Longitude: -71.21745275°W Phosphorus Reduction Credit BMP Type: Porous Pavement Drainage Area: Land Use: Commercial Impervious Area (acres): 0.90 Directly Connected Impervious Area (acres): 0.72 Pervious Area (acres): 0.19 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.82 Maintenance and Inspection BMP Permit/Construction Date: June 18, 2018 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Massachusetts Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: April 20, 2022 (Inspector: AET, Inspection ID: INSP-123-SWBMP) Notes: Permit Number: 201-1082 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 18 BMP Location Address: 20 Pelham Parcel ID: 31-65A BMP ID: MGT 141 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Children’s Place Approximate Coordinates: Latitude: 42.43783266°N Longitude: -71.2177317°W Phosphorus Reduction Credit BMP Type: Detention Pond Drainage Area: Land Use: Commercial Impervious Area (acres): 0.73 Directly Connected Impervious Area (acres): 0.21 Pervious Area (acres): 4.33 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.20 Maintenance and Inspection BMP Permit/Construction Date: June 18, 2018 (BMP Permit) Name of Owner: Town of Lexington Owner Contact: 1625 Massachusetts Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: April 20, 2022 (Inspector: AET, Inspection ID: INSP-127-SWBMP) Notes: Permit Number: 201-1082 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Standing water, however it rained the previous day. Photo of Existing BMP BMP Verification Date: April 20, 2022 19 BMP Location Address: 7 Crosby Road Parcel ID: 51-45A BMP ID: MGT 187 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44571684°N Longitude: -71.2542899°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 1.24 Directly Connected Impervious Area (acres): 1.21 Pervious Area (acres): 0.10 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 2.14 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20, 2022 20 BMP Location Address: 7 Crosby Road Parcel ID: 51-45A BMP ID: MGT 182 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44525131°N Longitude: -71.25434254°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 1.08 Directly Connected Impervious Area (acres): 1.00 Pervious Area (acres): 2.03 Hydrologic Soil Group: A/C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 2.04 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20, 2022 21 BMP Location Address: 7 Crosby Road Parcel ID: 51-45A BMP ID: MGT 183 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44479374°N Longitude: -71.25437413°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 0.82 Directly Connected Impervious Area (acres): 0.81 Pervious Area (acres): 0.16 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): B BATT Calculated Credit (lbs/year): 1.44 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20, 2022 22 BMP Location Address: 7 Crosby Road Parcel ID: 51-45A BMP ID: MGT 188 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44664815°N Longitude: -71.25491753°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 0.50 Directly Connected Impervious Area (acres): 0.32 Pervious Area (acres): 1.87 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.92 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 23 BMP Location Address: 7 Crosby Road Parcel ID: 51-45A BMP ID: MGT 190 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44529695°N Longitude: -71.25377332°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 0.33 Directly Connected Impervious Area (acres): 0.29 Pervious Area (acres): 0.70 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.72 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Standing water but rained previous day. Photo of Existing BMP BMP Verification Date: April 20, 2022 24 BMP Location Address: 7 Crosby Rd Parcel ID: 51-45A BMP ID: MGT 189 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44444065 °N Longitude: -71.2547763 °W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 0.09 Directly Connected Impervious Area (acres): 0.00 Pervious Area (acres): 0.78 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.31 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 25 BMP Location Address: 7 Crosby Rd Parcel ID: 51-45A BMP ID: MGT 205 Property Type: ☐ Residential ☒ Non-residential Facility: Maria Hastings Elementary School Approximate Coordinates: Latitude: 42.44532922 °N Longitude: -71.25352505°W Phosphorus Reduction Credit BMP Type: Porous Pavement Drainage Area: Land Use: Commercial Impervious Area (acres): 0.93 Directly Connected Impervious Area (acres): 1.05 Pervious Area (acres): 0.12 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.84 Maintenance and Inspection BMP Permit/Construction Date: December 6, 2017 (BMP Permit) Name of Owner: Town of Lexington – Maria Hastings School Owner Contact: 1625 Mass Ave, Lexington, MA 02420 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 20, 2022 26 BMP Location BMP Observation Notes: Under construction. Address: 1050 Waltham Street Parcel ID: 5-14 BMP ID: MGT 302 Property Type: ☐ Residential ☒ Non-residential Facility: Lab/Offices Approximate Coordinates: Latitude: 42.414063°N Longitude: -71.231818°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 1.95 Directly Connected Impervious Area (acres): Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 3.17 Maintenance and Inspection BMP Permit/Construction Date: July 29, 2020 (Permit Date) Name of Owner: Greatland Realty Partners/Revolution Labs Owner Contact: 101 Federal Street, Boston, MA, (856) 209- 8202 Name of Operator (if applicable): N/A Operator Contact: N/A Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1189 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: N/A Photo of Existing BMP BMP Verification Date: May 18, 2022 27 BMP Location Address: 453 Concord Ave Parcel ID: 10-41A BMP ID: MGT 268 Property Type: ☐ Residential ☒ Non-residential Facility: Cotting School Approximate Coordinates: Latitude: 42.42068537°N Longitude: -71.23832576°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 0.78 Directly Connected Impervious Area (acres): 0.74 Pervious Area (acres): 0.33 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 1.13 Maintenance and Inspection BMP Permit/Construction Date: August 12, 2019 (Site Plan Review Submission) Name of Owner: Cotting School Owner Contact: 453 Concord Ave, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 28 BMP Location Address: 453 Concord Ave Parcel ID: 10-41A BMP ID: MGT 269 Property Type: ☐ Residential ☒ Non-residential Facility: Cotting School Approximate Coordinates: Latitude: 42.41996661°N Longitude: -71.23833113°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 0.32 Directly Connected Impervious Area (acres): 0.20 Pervious Area (acres): 0.04 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 0.27 BATT Calculated Credit (lbs/year): 0.41 Maintenance and Inspection BMP Permit/Construction Date: August 12, 2019 (Site Plan Review Submission) Name of Owner: Cotting School Owner Contact: 453 Concord Ave, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 29 BMP Location BMP Observation Notes: Under construction. Address: 300 Shire Way, 200 Shire Way, 400 Shire Way Parcel ID: 18-15D/F/G BMP ID: MGT 264 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.42749234°N Longitude: -71.25340716°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 1.47 Directly Connected Impervious Area (acres): 1.50 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 2.39 Maintenance and Inspection BMP Permit/Construction Date: October 4, 2016 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-719 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access, active construction. Photo of Existing BMP BMP Verification Date: May 18, 2022 30 BMP Location BMP Observation Notes: Overgrown. Unable to confirm location. Address: 300 Shire Way, 200 Shire Way, 400 Shire Way Parcel ID: 18-15D/F/G BMP ID: MGT 267 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.42674509°N Longitude: -71.25352996°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 2.05 Directly Connected Impervious Area (acres): 1.55 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 3.41 Maintenance and Inspection BMP Permit/Construction Date: October 4, 2016 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-719 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Overgrown area, unable to confirm location. Photo of Existing BMP BMP Verification Date: May 18, 2022 31 BMP Location Address: 300 Shire Way, 200 Shire Way, 400 Shire Way Parcel ID: 18-15D/F/G BMP ID: MGT 306 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.425971°N Longitude: -71.251968°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): 1.17 Directly Connected Impervious Area (acres): 1.16 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.52 BATT Calculated Credit (lbs/year): 1.56 Maintenance and Inspection BMP Permit/Construction Date: October 4, 2016 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-719 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 32 BMP Location Address: 300 Shire Way, 200 Shire Way, 400 Shire Way Parcel ID: 18-15D/F/G BMP ID: MGT 265 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.42821016°N Longitude: -71.25451165°W Phosphorus Reduction Credit BMP Type: Wet Pond Drainage Area: Land Use: Commercial Impervious Area (acres): 15.1 Directly Connected Impervious Area (acres): 14.99 Pervious Area (acres): 4.12 / 15.97 Hydrologic Soil Group: C / D BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 8.90 Maintenance and Inspection BMP Permit/Construction Date: October 4, 2016 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-719 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Overgrown. Standing water observed. Photo of Existing BMP BMP Verification Date: May 18, 2022 33 BMP Location Address: 187 Spring Street Parcel ID: 12-3 BMP ID: MGT 200 Property Type: ☐ Residential ☒ Non-residential Facility: Therapeutic Day School Approximate Coordinates: Latitude: 42.42062017°N Longitude: -71.25174339°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Commercial Impervious Area (acres): 0.05 Directly Connected Impervious Area (acres): 0.04 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.09 Maintenance and Inspection BMP Permit/Construction Date: October 2, 2014 (Building Permit) Name of Owner: Community Therapeutic Day School Inc. Owner Contact: 187 Spring St, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20, 2022 34 BMP Location BMP Observation Notes: No site plans during visit. Address: 39 Marrett Road Parcel ID: 31-63D BMP ID: MGT 322 Property Type: ☐ Residential ☒ Non-residential Facility: Lexington Community Center Approximate Coordinates: Latitude: 42.436986°N Longitude: -71.217599°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: Commercial Impervious Area (acres): 1.14 Directly Connected Impervious Area (acres): Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 2.03 Maintenance and Inspection BMP Permit/Construction Date: July 30, 1999 (Permit Date) Name of Owner: Town of Lexington Owner Contact: Name of Operator (if applicable): N/A Operator Contact: N/A Date of Last Completed Maintenance: Date of Last Completed Inspection: None Found Notes: Permit Number: None Found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: N/A Photo of Existing BMP BMP Verification Date: N/A BMP verification photo unavailable 35 BMP Fact Sheets Residential Properties 36 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 293 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41639313°N Longitude: -71.23125174°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.17 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.38 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 37 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 292 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.4160465°N Longitude: -71.2313188°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.55 Pervious Area (acres): 0.65/0.28 Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 1.062 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 38 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 294 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41615534°N Longitude: -71.23124059°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.32 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.736 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 39 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 295 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41603611°N Longitude: -71.23011759°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.07 Pervious Area (acres): N/A Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.15 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 40 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 296 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41638387°N Longitude: -71.23022814°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.30 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.70 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Basin area in need of mowing. Photo of Existing BMP BMP Verification Date: May 18, 2022 41 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 297 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41544774°N Longitude: -71.23073479°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.30 Pervious Area (acres): 0.14/0.19 Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 2.01 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 42 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 298 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41574944°N Longitude: -71.23228749°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.18 Pervious Area (acres): N/A Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.38 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022 Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 43 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 291 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41580286°N Longitude: -71.23124474°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.41 Pervious Area (acres): 0.20/0.13 Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.46 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022 Inspector: Kendra Dow and Hannah Schulz) Basin is slightly overgrown. Photo of Existing BMP BMP Verification Date: May 18, 2022 44 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 290 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.41580733°N Longitude: -71.2315099°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.37 Pervious Area (acres): 0.65/0.28 Hydrologic Soil Group: B/D BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.72 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Basin is slightly overgrown. Photo of Existing BMP BMP Verification Date: May 18, 2022 45 BMP Location Address: 960-1010 Waltham Street Parcel ID: 5-20; 5-21A BMP ID: MGT 330 Property Type: ☒ Residential ☐ Non-residential Facility: Independent Living Approximate Coordinates: Latitude: 42.415651°N Longitude: -71.230437°W Phosphorus Reduction Credit BMP Type: Wet Detention Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.32 Pervious Area (acres): 1.53 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: July 17, 2017 Name of Owner: Symmes Life Care Inc Owner Contact: 1010 Waltham St Suite 600, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1066 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: N/A Photo of Existing BMP BMP Verification Date: May 18, 2022 46 BMP Location BMP Observation Notes: Under construction at time of inspection. Address: 55 Watertown Parcel ID: 3-15 BMP ID: MGT 331 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: °N Longitude: °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: High Density Residential Impervious Area (acres): 2.51 Pervious Area (acres): 2.06 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 1.95 BATT Calculated Credit (lbs/year): 4.94 Maintenance and Inspection BMP Permit/Construction Date: April 30, 2019 Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☐ No O&M Observations at BMP Verification: (Date: Month XX, 202X, Inspector: ) Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 47 BMP Location BMP Observation Notes: Under construction at time of inspection. Address: 55 Watertown Parcel ID: 3-15 BMP ID: MGT 332 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: °N Longitude: °W Phosphorus Reduction Credit BMP Type: Extended Dry Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.32 Pervious Area (acres): 1.53 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: April 30, 2019 Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☐ No O&M Observations at BMP Verification: (Date: Month XX, 202X, Inspector: ) Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 48 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 217 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41623899°N Longitude: -71.20395558°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.97 Pervious Area (acres): 0.71 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 2.23 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 20. 2022 49 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 219 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41591381 °N Longitude: -71.20327095 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.38 Pervious Area (acres): 0.92 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.88 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21. 2022 50 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 216 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41607127°N Longitude: -71.2039011°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.44 Pervious Area (acres): 1.38 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.84 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 51 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 215 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41594332°N Longitude: -71.20376498°W Phosphorus Reduction Credit BMP Type: Bioretention Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): 0.05 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.11 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 21, 2022 52 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 214 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41532549°N Longitude: -71.20361033°W Phosphorus Reduction Credit BMP Type: Bioretention Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.06 Pervious Area (acres): 0.03 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.14 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 21, 2022 53 BMP Location Address: 56 Watertown Parcel ID: 3-16 BMP ID: MGT 218 Property Type: ☐ Residential ☒ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41643944°N Longitude: -71.20328955°W Phosphorus Reduction Credit BMP Type: Bioretention Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.12 Pervious Area (acres): 0.35 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.25 Maintenance and Inspection BMP Permit/Construction Date: April 12, 2019 Name of Owner: Lexington Senior Housing Owner LLLC Owner Contact: 2310 Washington St, Newton Lower Falls MA 02462 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Grass growth in progress. Good condition. Photo of Existing BMP BMP Verification Date: April 21, 2022 54 BMP Location Address: 62 Grassland Parcel ID: 24-7A BMP ID: MGT 211 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43217085°N Longitude: -71.23793991°W Phosphorus Reduction Credit BMP Type: Pervious Pavers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.02 Maintenance and Inspection BMP Permit/Construction Date: May 29, 2014 Name of Owner: Chong Homing & Yau Ellie Owner Contact: 62 Grassland St, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 21, 2022 55 BMP Location BMP Observation Notes: Could not access backyard. Address: 72 Grassland Parcel ID: 24-5G BMP ID: MGT 212 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43194332°N Longitude: -71.2370692°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Single Family Residential Impervious Area (acres): 0.03 Pervious Area (acres): 0.16 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.08 Maintenance and Inspection BMP Permit/Construction Date: January 12, 2021 Name of Owner: Mannem Venkat R & Mannem Lakshmi Owner Contact: 72 Grassland St, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 20, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 56 BMP Location Address: 310 Concord Ave Parcel ID: 9-8 BMP ID: MGT 213 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.41742163°N Longitude: -71.22733284°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.01 Maintenance and Inspection BMP Permit/Construction Date: July 29, 2008 Name of Owner: Maliszewski Jan & Maliszewski Rena Fraser Owner Contact: 310 Concord Ave, Lexington, MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-748 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 57 BMP Location Address: 443 Lincoln Street (Hobbs Brook Ln) Parcel ID: 35-2 BMP ID: MGT 210 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43638762°N Longitude: -71.26501907°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.22 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.50 Maintenance and Inspection BMP Permit/Construction Date: February 20, 2018 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1101 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 58 BMP Location Address: 443 Lincoln Street (Hobbs Brook Ln) Parcel ID: 35-2 BMP ID: MGT 209 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.4367757°N Longitude: -71.26488311°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.34 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.78 Maintenance and Inspection BMP Permit/Construction Date: February 20, 2018 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1101 Discharge to MS4? Yes No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Eroded spillway in need of repair. Photo of Existing BMP BMP Verification Date: April 21, 2022 59 BMP Location Address: 8 Cutler Farm Road Parcel ID: 25-1 BMP ID: MGT 225 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4294267°N Longitude: -71.23997585°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.22 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.11 Maintenance and Inspection BMP Permit/Construction Date: January 26, 2012 (Construction Date) Name of Owner: Eaglesham Jennifer D Trustee Owner Contact: 8 Cutler Farm Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-844 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 60 BMP Location Address: 8 Cutler Farm Road Parcel ID: 25-1 BMP ID: MGT 224 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42956531°N Longitude: -71.23963827°W Phosphorus Reduction Credit BMP Type: Infiltration Trench Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.05 Maintenance and Inspection BMP Permit/Construction Date: January 26, 2012 (Construction Date) Name of Owner: Eaglesham Jennifer D Trustee Owner Contact: 8 Cutler Farm Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-844 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 61 BMP Location Address: 13 Cutler Farm Road Parcel ID: 25-6 BMP ID: MGT 226 Property Type: ☒ Residential ☐ Non-residential Facility: Infiltration Chamber Approximate Coordinates: Latitude: 42.42851397 °N Longitude: -71.24072246 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.04 Maintenance and Inspection BMP Permit/Construction Date: February 15, 2006 (Construction Date) Name of Owner: Connor Peter & Kieslich Maria T Owner Contact: 13 Cutler Farm Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 62 BMP Location BMP Observation Notes: BMP not in location on plans. Two inlets from roof drain in front yard. Address: 14 Cutler Farm Road Parcel ID: 25-4 BMP ID: MGT 227 Property Type: ☒ Residential ☐ Non-residential Facility: Infiltration Chamber Approximate Coordinates: Latitude: 42.42850571°N Longitude: -71.2397313°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.06 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.00 BATT Calculated Credit (lbs/year): 0.12 Maintenance and Inspection BMP Permit/Construction Date: April 6, 2008 (BMP Permit) Name of Owner: Taranto Thomas R & Taranto Lisa A Owner Contact: 14 Cutler Farm Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-733 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 63 BMP Location Address: 116 School Street Parcel ID: 42-218 BMP ID: MGT 245 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42760944 °N Longitude: -71.24528539 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.11 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.27 BATT Calculated Credit (lbs/year): 0.20 Maintenance and Inspection BMP Permit/Construction Date: December 7, 2016 (Construction Date) Name of Owner: Butchatskiy Eveline & Buchatskiy Igor Owner Contact: 116 School Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-965 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 64 BMP Location Address: 33 Dawes Road Parcel ID: 23-1 BMP ID: MGT 236 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42762786 °N Longitude: -71.21762067 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers (2) Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.048 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: June 10, 2008 Name of Owner: Colin Micheal C & Weinstock Amy K Trs Contact: 33 Dawes Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Inspection port not found. Spoke with resident to confirm construction. Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 65 BMP Location Address: 33 Dawes Road Parcel ID: 23-1 BMP ID: MGT 237 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42791896°N Longitude: -71.21739721 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers (2) Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.048 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: June 10, 2008 Name of Owner: Colin Micheal C & Weinstock Amy K Trs Contact: 33 Dawes Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 66 BMP Location Address: 37 Barberry Road Parcel ID: 11-59 BMP ID: MGT 220 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.41855223°N Longitude: -71.24713611°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers (3) Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): 0.00 Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 5.76 BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: March 15, 2005 Name of Owner: Beeman Yvette A Owner Contact: 37 Barberry Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-651 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 67 BMP Location Address: 37 Barberry Road Parcel ID: 11-59 BMP ID: MGT 221 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.41861262°N Longitude: -71.2470958W Phosphorus Reduction Credit BMP Type: Infiltration Chambers (3) Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): 0.00 Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 5.76 BATT Calculated Credit (lbs/year): 0.01 Maintenance and Inspection BMP Permit/Construction Date: March 15, 2005 Name of Owner: Beeman Yvette A Owner Contact: 37 Barberry Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-651 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 68 BMP Location Address: 37 Barberry Road Parcel ID: 11-59 BMP ID: MGT 222 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4186508°N Longitude: -71.24698365°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers (3) Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): 0.09 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 5.76 BATT Calculated Credit (lbs/year): 0.09 Maintenance and Inspection BMP Permit/Construction Date: March 15, 2005 Name of Owner: Beeman Yvette A Owner Contact: 37 Barberry Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-651 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 69 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: 9 Woodcliffe Road Parcel ID: 17-15 BMP ID: MGT 223 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4269 °N Longitude: -71.2448 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.045 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.50 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: September 6, 2005 Name of Owner: Greely David S & Nies Nancy S Owner Contact: 9 Woodcliffe Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-602 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Unable to access backyard. Fenced. Photo of Existing BMP BMP Verification Date: April 21, 2022 70 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: 66 Valleyfield Street Parcel ID: 24-47B BMP ID: MGT 246 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4307°N Longitude: -71.2364°W Phosphorus Reduction Credit BMP Type: Subsurface Infiltration Trench Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.047 Pervious Area (acres): 0.0 Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.50 BATT Calculated Credit (lbs/year): 0.05 Maintenance and Inspection BMP Permit/Construction Date: January 27, 2006 Name of Owner: Lou Yike & Zhang Zhi Yin Owner Contact: 66 Valleyfield Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-680 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Fenced. Photo of Existing BMP BMP Verification Date: April 21, 2022 71 BMP Location Address: 65 Munroe Road Parcel ID: 25-84A BMP ID: MGT 242 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4274 °N Longitude: -71.2464 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.06 Pervious Area (acres): 0.0 Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.50 BATT Calculated Credit (lbs/year): 0.12 Maintenance and Inspection BMP Permit/Construction Date: 4/18/13 Name of Owner: Singh Prashant & Kaur Meenal Owner Contact: 64 Munroe Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-823 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 72 BMP Location Address: 66 Munroe Road Parcel ID: 17-18 BMP ID: MGT 241 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4275 °N Longitude: -71.2459 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium Density-Residential Impervious Area (acres): 0.049 Pervious Area (acres): 0.0 Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 5.98 BATT Calculated Credit (lbs/year): 0.10 Maintenance and Inspection BMP Permit/Construction Date: April 18, 2013 Name of Owner: Chen Ying Owner Contact: 66 Munroe Rd, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-823 Discharge to MS4? Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 73 BMP Location Address: 10 Philip Road Parcel ID: 15-67B BMP ID: MGT 239 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42553983 °N Longitude: -71.21566976 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.08 Pervious Area (acres): 0.08 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 0.52 BATT Calculated Credit (lbs/year): 0.16 Maintenance and Inspection BMP Permit/Construction Date: November 26, 2014 Name of Owner: Clark, Matthew & Zhang , Xin Owner Contact: 10 Philip Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-957 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Cleanout of trench drain needed. Leaf litter. Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 74 BMP Location Address: 10 Philip Road Parcel ID: 15-67B BMP ID: MGT 238 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.42555615°N Longitude: -71.21578728 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): 0.02 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 0.52 BATT Calculated Credit (lbs/year): 0.02 Maintenance and Inspection BMP Permit/Construction Date: November 26, 2014 Name of Owner: Clark, Matthew & Zhang , Xin Owner Contact: 10 Philip Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-957 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 75 BMP Location Address: 470 Concord Avenue Parcel ID: 11-47 BMP ID: MGT 240 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4189 °N Longitude: -71.2390 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: May 22, 2012 Name of Owner: Prestbo Bradford J & Prestbo John Owner Contact: 470 Concord Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None Found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 76 BMP Location Address: 60 Munroe Road Parcel ID: 17-17 BMP ID: MGT 243 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4278 °N Longitude: -71.2457 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.08 Pervious Area (acres): N/A Hydrologic Soil Group: C/D BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.16 Maintenance and Inspection BMP Permit/Construction Date: December 21, 2016 Name of Owner: Lewis Robert B & Galofre-Leis Judy Owner Contact: 60 Munroe Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: Not found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 77 BMP Location Address: 60 Munroe Road Parcel ID: 17-17 BMP ID: MGT 244 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4278 °N Longitude: -71.2457 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.084 Pervious Area (acres): N/A Hydrologic Soil Group: HSG C/D BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.16 Maintenance and Inspection BMP Permit/Construction Date: 12/21/16 Name of Owner: Lewis Robert B & Galofre-Leis Judy Owner Contact: 60 Munroe Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: Not found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 78 BMP Location Address: 10 Churchill Lane Parcel ID: 23-19 BMP ID: MGT 232 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43246532°N Longitude: -71.21736147°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.09 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.17 Maintenance and Inspection BMP Permit/Construction Date: January 4, 2016 Name of Owner: Wang Fred & Shi Zhimin Owner Contact: 10 Churchill Lane, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-02 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 79 BMP Location Address: 10 Churchill Lane Parcel ID: 23-19 BMP ID: MGT 233 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43275845°N Longitude: -71.21717764°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.06 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.13 Maintenance and Inspection BMP Permit/Construction Date: January 4, 2016 Name of Owner: Wang Fred & Shi Zhimin Owner Contact: 10 Churchill Lane, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-02 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 80 BMP Location Address: 71 Bridge Street Parcel ID: 24-1 BMP ID: MGT 247 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4332 °N Longitude: -71.2367 °W Phosphorus Reduction Credit BMP Type: Drywell Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.01 Maintenance and Inspection BMP Permit/Construction Date: December 14, 2010 Name of Owner: Fung Michael & Fung Susan Yan Owner Contact: 71 Bridge Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Submerged inlet found in yard. Yard saturated. Inlet had puddling with discolored water. Cleanout required. Photo of Existing BMP BMP Verification Date: April 21, 2022 81 BMP Location Address: 12 Brookside Avenue Parcel ID: 24-93 BMP ID: MGT 228 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43158904°N Longitude: -71.23207236 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.02 Maintenance and Inspection BMP Permit/Construction Date: October 5, 2015 Name of Owner: Macchia Stephen A & Ruth L Owner Contact: 12 Brookside Avenue, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-100 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 82 BMP Location Address: 12 Brookside Avenue Parcel ID: 24-93 BMP ID: MGT 229 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43162121°N Longitude: -71.23200663°W Phosphorus Reduction Credit BMP Type: Infiltration Trench Drainage Area: Land Use: Low-Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.02 Maintenance and Inspection BMP Permit/Construction Date: October 5, 2015 Name of Owner: Macchia Stephen A & Ruth L Owner Contact: 12 Brookside Avenue, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-100 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: April 21, 2022 83 BMP Location BMP Obersvation Notes: Unable to communicate with resident. Could not access. Address: 2 Brookside Ave Parcel ID: 24-95 BMP ID: MGT 230 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43160015°N Longitude: -71.23257849°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.04 Maintenance and Inspection BMP Permit/Construction Date: February 25, 2014 Name of Owner: Duan Penggao Owner Contact: 2 Brookside Avenue, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-924 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Unable to communicate with resident. Could not access. Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 84 BMP Location BMP Obersvation Notes: Unable to communicate with resident. Could not access. Address: 2 Brookside Ave Parcel ID: 24-95 BMP ID: MGT 325 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.431581°N Longitude: -71.232557°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: February 25, 2014 Name of Owner: Duan Penggao Owner Contact: 2 Brookside Avenue, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-924 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Unable to communicate with resident. Could not access. Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 85 BMP Location Address: 114 Marrett Rd Parcel ID: 31-51 BMP ID: MGT 234 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4347°N Longitude: -71.2194°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.04 Maintenance and Inspection BMP Permit/Construction Date: June 2, 2009 Name of Owner: Dailey William J Jr Owner Contact: 114 Marrett Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect Photo of Existing BMP BMP Verification Date: May 18, 2022 86 BMP Location BMP Observation Notes: Could not access backyard. Address: 114 Marrett Rd Parcel ID: 31-51 BMP ID: MGT 326 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.434176°N Longitude: -71.219993°W Phosphorus Reduction Credit BMP Type: Infiltration Trench Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: June 2, 2009 Name of Owner: Dailey William J Jr Owner Contact: 114 Marrett Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 87 BMP Location Address: 14 Middle Street Parcel ID: 34-57 BMP ID: MGT 248 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.43582°N Longitude: -71.2497°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.04 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 5.98 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: November 19, 2013 Name of Owner: Belmonte Louis R Owner Contact: 14 Middle Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-913 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 88 BMP Location BMP Observation Notes: Could not access backyard. Address: 14 Middle Street Parcel ID: 34-57 BMP ID: MGT 327 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42°26'7.86 °N Longitude: 71°14'59.56 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.03 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 5.98 BATT Calculated Credit (lbs/year): 0.06 Maintenance and Inspection BMP Permit/Construction Date: November 19, 2013 Name of Owner: Belmonte Louis R Owner Contact: 14 Middle Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-913 Discharge to MS4? ☐ Yes ☐ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Photo of Existing BMP BMP Verification Date: May 18, 2022 BMP verification photo unavailable 89 BMP Location Address: 26 Middle Street Parcel ID: 34-63 BMP ID: MGT 253 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4359°N Longitude: -71.2509°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.03 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.06 Maintenance and Inspection BMP Permit/Construction Date: January 11, 2005 Name of Owner: Sing Hathai Owner Contact: 26 Middle Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-632 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface unable to inspect Photo of Existing BMP BMP Verification Date: May 18, 2022 90 BMP Location Address: 64 Middle Street Parcel ID: 34-78 BMP ID: MGT 259 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4364 °N Longitude: -71.2544 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.01 Maintenance and Inspection BMP Permit/Construction Date: October 31, 2007 Name of Owner: Burstein Johnathan L Owner Contact: 64 Middle Street, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 08-02 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 91 BMP Location Address: 17 Cary Ave Parcel ID: 34-50 BMP ID: MGT 252 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4351°N Longitude: -71.2496°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.03 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.05 Maintenance and Inspection BMP Permit/Construction Date: June 29, 2006 Name of Owner: Matejcik Anton Owner Contact: 17 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 92 BMP Location Address: 17 Cary Ave Parcel ID: 34-50 BMP ID: MGT 251 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4352°N Longitude: -71.249°W Phosphorus Reduction Credit BMP Type: Infiltration Trench Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.015 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.24 BATT Calculated Credit (lbs/year): 0.02 Maintenance and Inspection BMP Permit/Construction Date: June 29, 2006 Name of Owner: Matejcik Anton Owner Contact: 17 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Leaf litter. Photo of Existing BMP BMP Verification Date: May 18, 2022 93 BMP Location Address: 31 Cary Ave Parcel ID: 34-47A BMP ID: MGT 256 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4346°N Longitude: -71.2503°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: December 28, 2004 Name of Owner: McCandless Michael Kyle Owner Contact: 31 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-752 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 94 BMP Location Address: 33 Cary Ave Parcel ID: 34-47B BMP ID: MGT 255 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.434°N Longitude: -71.250°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.07 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.08 Maintenance and Inspection BMP Permit/Construction Date: December 28, 2004 Name of Owner: Mitzenchacher Michael D Owner Contact: 33 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: N/A Notes: Permit Number: 201-752 Discharge to MS4? ☐ Yes ☐ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect Photo of Existing BMP BMP Verification Date: May 18, 2022 95 BMP Location Address: 35 Cary Ave Parcel ID: 34-47E BMP ID: MGT 254 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4345°N Longitude: -71.2505 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 0.17 BATT Calculated Credit (lbs/year): 0.07 Maintenance and Inspection BMP Permit/Construction Date: December 28, 2004 Name of Owner: Chuang Isaac L Chuang Isaac L Owner Contact: 35 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-752 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, Unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 96 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: Cary Ave Parcel ID: 34-41A BMP ID: MGT 328 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42°26'3.27°N Longitude: 71°15'5.44°W Phosphorus Reduction Credit BMP Type: Detention Basin Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.142 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: December 28, 2004 Name of Owner: Chuang Isaac L Owner Contact: 35 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-752 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: Month XX, 20XX, Inspector: ) Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 97 BMP Location Address: 55 Cary Ave Parcel ID: 34-41A BMP ID: MGT 257 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4335 °N Longitude: -71.2508 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.03 Maintenance and Inspection BMP Permit/Construction Date: January 22, 2018 Name of Owner: Melhem Murad Owner Contact: 55 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1083 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: April 21, 2022 98 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: 55 Cary Ave Parcel ID: 34-41A BMP ID: MGT 258 Property Type: ☒ Residential ☐ Non-residential Facility: Single Family Approximate Coordinates: Latitude: 42.4336 °N Longitude: -71.2510 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium Density Residential Impervious Area (acres): 0.02 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 0.04 Maintenance and Inspection BMP Permit/Construction Date: January 22, 2018 Name of Owner: Melhem Murad Owner Contact: 55 Cary Ave, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-1083 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Fenced. Photo of Existing BMP BMP Verification Date: April 21, 2022 99 BMP Location Address: 341 Marrett Road Parcel ID: 33-264A BMP ID: MGT 284 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.43592323 °N Longitude: -71.23621763 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.01 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 8.27 BATT Calculated Credit (lbs/year): 0.23 Maintenance and Inspection BMP Permit/Construction Date: None found Name of Owner: Condo Complex, Owner TBD Owner Contact: 341 Marrett Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #09-01 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 100 BMP Location Address: 341 Marrett Road Parcel ID: 33-264A BMP ID: MGT 285 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.43592323°N Longitude: -71.23621763 °W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.43 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.973 Maintenance and Inspection BMP Permit/Construction Date: None found Name of Owner: Condo Complex, Owner TBD Owner Contact: 341 Marrett Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #09-01 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface unable to inspect. Missing cap at inspection port. Photo of Existing BMP BMP Verification Date: May 18, 2022 101 BMP Location Address: 341 Marrett Road Parcel ID: 33-264A BMP ID: MGT 323 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42°26'8.75"N Longitude: 71°14'10.99"W Phosphorus Reduction Credit BMP Type: Leaching CB Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.049 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.11 Maintenance and Inspection BMP Permit/Construction Date: None found Name of Owner: Condo Complex, Owner TBD Owner Contact: 341 Marrett Road, Lexington MA 02421 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #09-01 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 102 BMP Location Address: Journeys End Lane Parcel ID: 26-44F BMP ID: MGT 263 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.431075°N Longitude: -71.25418235°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.29 Pervious Area (acres): 1.78 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 1.01 Maintenance and Inspection BMP Permit/Construction Date: May 24, 2007 Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Photo of Existing BMP BMP Verification Date: May 18, 2022 103 BMP Location Address: Journeys End Lane Parcel ID: 26-44F BMP ID: MGT 262 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.43265417°N Longitude: -71.25423276°W Phosphorus Reduction Credit BMP Type: Exfiltrating Bioretention- Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.68 Pervious Area (acres): 2.64 Hydrologic Soil Group: C BMP Infiltration Rate (in/hr): 1.02 BATT Calculated Credit (lbs/year): 2.13 Maintenance and Inspection BMP Permit/Construction Date: May 24, 2007 Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Good Condition Photo of Existing BMP BMP Verification Date: May 18, 2022 104 BMP Location Address: 430 Concord Ave Parcel ID: 10-8 BMP ID: MGT 270 Property Type: ☒ Residential ☐ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41818453°N Longitude: -71.23591446°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.91 Pervious Area (acres): 0.38 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 2.12 Maintenance and Inspection BMP Permit/Construction Date: August 15, 2014 Name of Owner: Artis Senior Living of Lexington LLC Owner Contact: 680 American Ave Suite #101, King of Prussia PA 19406 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: N/A Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface. Unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 105 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: 430 Concord Ave Parcel ID: 10-8 BMP ID: MGT 271 Property Type: ☒ Residential ☐ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42.41731328°N Longitude: -71.23571°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.58 Pervious Area (acres): 0.67 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 1.41 Maintenance and Inspection BMP Permit/Construction Date: None found Name of Owner: Artis Senior Living of Lexington LLC Owner Contact: 680 American Ave Suite #101, King of Prussia PA 19406 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: April 21, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Fenced. Photo of Existing BMP BMP Verification Date: May 18, 2022 106 BMP Location BMP Observation Notes: Could not access backyard. Fenced. Address: 430 Concord Ave Parcel ID: 10-8 BMP ID: MGT 324 Property Type: ☒ Residential ☐ Non-residential Facility: Assisted Living Approximate Coordinates: Latitude: 42°25'3.16 °N Longitude: 71°14'11.31°W Phosphorus Reduction Credit BMP Type: Wetland Replication Drainage Area: Land Use: High Density Residential Impervious Area (acres): 2.05 Pervious Area (acres): 4.89 Hydrologic Soil Group: B BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 1.05 Maintenance and Inspection BMP Permit/Construction Date: None found Name of Owner: Artis Senior Living of Lexington LLC Owner Contact: 680 American Ave Suite #101, King of Prussia PA 19406 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Could not access backyard. Fenced. Photo of Existing BMP BMP Verification Date: May 18, 2022 107 BMP Location Address: 1000 Main Campus Drive Parcel ID: 1-3 BMP ID: MGT 277 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.4069 °N Longitude: -71.2127°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.38 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.89 Maintenance and Inspection BMP Permit/Construction Date: September 21, 2004 Name of Owner: Avalonbay Communities Inc Owner Contact: 4040 Wilson Blvd #1000 Arlington, VA 22203 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #201-640 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface. Unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 108 BMP Location Address: 1000 Main Campus Drive Parcel ID: 1-3 BMP ID: MGT 275 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.4078 °N Longitude: -71.2135 °W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.084 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.193 Maintenance and Inspection BMP Permit/Construction Date: September 21, 2004 Name of Owner: Avalonbay Communities Inc Owner Contact: 4040 Wilson Blvd #1000 Arlington, VA 22203 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #201-640 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 109 BMP Location Address: 1000 Main Campus Drive Parcel ID: 1-3 BMP ID: MGT 274 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.4085°N Longitude: -71.211°W Phosphorus Reduction Credit BMP Type: Wetland Replication Drainage Area: Land Use: High Density Residential Impervious Area (acres): 0.09 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.20 Maintenance and Inspection BMP Permit/Construction Date: September 21, 2004 Name of Owner: Avalonbay Communities Inc Owner Contact: 4040 Wilson Blvd #1000 Arlington, VA 22203 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #201-640 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 110 BMP Location Address: 1000 Main Campus Drive Parcel ID: 1-3 BMP ID: MGT 276 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.4071°N Longitude: -71.21371°W Phosphorus Reduction Credit BMP Type: Infiltration Basin Drainage Area: Land Use: High Density Residential Impervious Area (acres): 9.34 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): N/A BATT Calculated Credit (lbs/year): 6.29 Maintenance and Inspection BMP Permit/Construction Date: September 21, 2004 Name of Owner: Avalonbay Communities Inc Owner Contact: 4040 Wilson Blvd #1000 Arlington, VA 22203 Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: #201-640 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Mowing and maintenance observed. Photo of Existing BMP BMP Verification Date: May 18, 2022 111 BMP Location Address: Grey Oaks Circle Parcel ID: 35-3A-995 BMP ID: MGT 307 through MGT 320 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.436059°N Longitude: -71.264004°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers/Dry Wells (14) Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.44 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.85 Maintenance and Inspection BMP Permit/Construction Date: May 24, 2016 (Permit Date) Name of Owner: North Shore Residential Development Inc. Owner Contact: 215 Salem Street, Woburn, MA Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None Found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 112 BMP Location Address: Grey Oaks Circle Parcel ID: 35-3A-995 BMP ID: MGT 45 Property Type: ☒ Residential ☐ Non-residential Facility: Condos Approximate Coordinates: Latitude: 42.435905°N Longitude: -71.263151°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.35 Pervious Area (acres): 0.23 Hydrologic Soil Group: A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.67 Maintenance and Inspection BMP Permit/Construction Date: May 24, 2016 (Permit Date) Name of Owner: North Shore Residential Development Inc. Owner Contact: 215 Salem Street, Woburn, MA Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: None Found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 113 BMP Location Address: 32 Middle Street Parcel ID: 34-66 BMP ID: MGT 321 Property Type: ☒ Residential ☐ Non-residential Facility: Single-Family Approximate Coordinates: Latitude: 42.435750°N Longitude: -71.251484°W Phosphorus Reduction Credit BMP Type: Infiltration Chambers Drainage Area: Land Use: Medium-Density Residential Impervious Area (acres): 0.05 Pervious Area (acres): N/A Hydrologic Soil Group: N/A BMP Infiltration Rate (in/hr): 2.41 BATT Calculated Credit (lbs/year): 0.10 Maintenance and Inspection BMP Permit/Construction Date: October 23, 2020 (Construction Date) Name of Owner: CUI SHENG & LIU XIAOHONG Owner Contact: None Found Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: January 3, 2022 (Creative Land & Water Engineering) Notes: Permit Number: None Found Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: N/A Photo of Existing BMP BMP Verification Date: October 23, 2020 114 BMP FACT SHEETS NOT CREDITED YET REQUIRE MORE INFORMATION 115 BMP Location Address: 3 Forbes Road Parcel ID: BMP ID: MGT 287 Property Type: ☐ Residential ☒ Non-residential Facility: Hotel Approximate Coordinates: Latitude: 42.44528848°N Longitude: -71.26199298°W Phosphorus Reduction Credit BMP Type: Detention Pond Drainage Area: Land Use: Commercial Impervious Area (acres): Directly Connected Impervious Area (acres): Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: September 22, 2006 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None Found Notes: Permit Number: Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Overgrown. In need of maintenance. Photo of Existing BMP BMP Verification Date: May 18, 2022 116 BMP Location Address: 500 Shire Road Parcel ID: BMP ID: MGT Property Type: ☐ Residential ☒ Non-residential Facility: Hotel Approximate Coordinates: Latitude: °N Longitude: °W Phosphorus Reduction Credit BMP Type: Detention Pond Drainage Area: Land Use: Commercial Impervious Area (acres): Directly Connected Impervious Area (acres): 0 Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: September 22, 2006 (BMP Permit) Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: Month XX, 202X, Inspector: ) Photo of Existing BMP BMP Verification Date: BMP verification photo unavailable 117 BMP Location Address: 45-55 Hayden Ave Parcel ID: 17-21A BMP ID: MGT 303 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.422898°N Longitude: -71.239036°W Phosphorus Reduction Credit BMP Type: Wetlands Drainage Area: Land Use: Impervious Area (acres): Directly Connected Impervious Area (acres): 0.76 Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Standing water observed. Photo of Existing BMP BMP Verification Date: May 18, 2022 118 BMP Location Address: 92 Hayden Ave Parcel ID: 18-4A BMP ID: MGT 304 Property Type: ☐ Residential ☒ Non-residential Facility: Offices Approximate Coordinates: Latitude: 42.42403415°N Longitude: -71.23882432°W Phosphorus Reduction Credit BMP Type: Detention pond Drainage Area: Land Use: (G) Impervious Area (acres): (L) Directly Connected Impervious Area (acres): Pervious Area (acres): (M) Hydrologic Soil Group: (N) BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Erosion observed. Note: Need outlet control structure information for credit. Photo of Existing BMP BMP Verification Date: May 18, 2022 119 BMP Location Address: 987 Waltham Street Parcel ID: 5-4B BMP ID: MGT 299 & 300 Property Type: ☒ Residential ☐ Non-residential Facility: Apartments Approximate Coordinates: Latitude: 42.414546°N Longitude: -71.233873°W Phosphorus Reduction Credit BMP Type: Infiltration Basins (3) Drainage Area: Land Use: Commercial Impervious Area (acres): Directly Connected Impervious Area (acres): Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: May 1, 1990 (Permit Date) Name of Owner: Lexington Ridge – Avalon Inc. Owner Contact: Name of Operator (if applicable): N/A Operator Contact: N/A Date of Last Completed Maintenance: Date of Last Completed Inspection: Outfall at MGT 299 (OF 523) inspected on August 9, 2019. Outfall at MGT 300 (OF524) inspected on August 8, 2019. Notes: Permit Number: Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Good condition. Note: Need outlet control structure information for credit. Photo of Existing BMP BMP Verification Date: May 18, 2022 120 BMP Location Address: 1060 Waltham Street Parcel ID: BMP ID: MGT 301 Property Type: ☐ Residential ☒ Non-residential Facility: Bank Approximate Coordinates: Latitude: 42.41332413°N Longitude: -71.23267299°W Phosphorus Reduction Credit BMP Type: Drainage Area: Land Use: Commercial Impervious Area (acres): Directly Connected Impervious Area (acres): Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: Name of Owner: Owner Contact: Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: Notes: Permit Number: Discharge to MS4? ☐ Yes ☐ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Under construction, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 121 BMP Location Address: 727 Marrett Road Parcel ID: 51-56A BMP ID: MGT 261 Property Type: ☐ Residential ☒ Non-residential Facility: Hotel Approximate Coordinates: Latitude: 42.44476573°N Longitude: -71.26023345°W Phosphorus Reduction Credit BMP Type: Infiltration Chamber Drainage Area: Land Use: Commercial Impervious Area (acres): Pervious Area (acres): Hydrologic Soil Group: BMP Infiltration Rate (in/hr): BATT Calculated Credit (lbs/year): Maintenance and Inspection BMP Permit/Construction Date: September 22, 2006 (BMP Permit) Name of Owner: Lixi Hospitality Lexington, Inc. Owner Contact: 4545 Boulevard Cote-Vertu, H4S1CB, St. Laurent, Quebec Name of Operator (if applicable): Operator Contact: Date of Last Completed Maintenance: Date of Last Completed Inspection: None found Notes: Permit Number: 201-692 Discharge to MS4? ☐ Yes ☒ No O&M Observations at BMP Verification: (Date: May 18, 2022, Inspector: Kendra Dow and Hannah Schulz) Subsurface, unable to inspect. Photo of Existing BMP BMP Verification Date: May 18, 2022 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 E.3: SCM Location Figures LegendFigure Exported: 6/24/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\BMP_Verification_Property Type.mxdProject #: 0227871.10Map Created: June 202200.25 0.50.125 Miles Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Charles River Basin Lexington Boundary Parcel BMP by Property Type Non-Residential Residential BMP Field VerificationProperty Types(Western Watershed)Charles River WatershedPhosphorous Control ProgramLexington, MA LegendCharles River WatershedPhosphorous Control Program Figure Exported: 6/24/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\BMP_Verification.mxdProject #: 0227871.10Map Created: June 202200.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Charles River Basin Lexington Boundary Parcel BMP Field Verified Yes No BMP Field Verification(Western Watershed) LegendFigure Exported: 6/24/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\BMP_Verification_Property Type.mxdProject #: 0227871.10Map Created: June 202200.25 0.50.125 Miles Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Charles River Basin Lexington Boundary Parcel BMP by Property Type Non-Residential Residential BMP Field VerificationProperty Types(Eastern Watershed)Charles River WatershedPhosphorous Control ProgramLexington, MA LegendCharles River WatershedPhosphorous Control Program Figure Exported: 6/24/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\BMP_Verification.mxdProject #: 0227871.10Map Created: June 202200.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Charles River Basin Lexington Boundary Parcel BMP Field Verified Yes No BMP Field Verification(Eastern Watershed) Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX F: PLANNED NON-STRUCTURAL CONTROL CREDIT CALCULATIONS F.1: Clean Sweep Memorandum F.2: Credit Calculations Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 F.1: Clean Sweep Memorandum Clean Sweep Recommendations for New and Updated Credits for Street Cleaning in New Hampshire Technical Memorandum Updated April 21, 2023 Contents 1.Executive Summary …3 2.Definition of Terms …4 3.About the Expert Panel and Its Process …6 4.Key Decisions …7 5.New: Measured Organic Matter Collection Credit …9 6.Update to Current Model-Based Street Cleaning Credit …10 7.Considerations When Applying the Credits …11 8.Appendices …12 ○Appendix A: References … 13 ○Appendix B: Suggested Areas of Future Research … 15 ○Appendix C: Clean Sweep Overview … 17 ○Appendix D: Clean Sweep Roles, Responsibilities, Timeline … 18 ○Appendix E: Clean Sweep Synthesis of Literature and Other Resources … 20 ○Appendix F: Summary of Credit Programs in New Hampshire, Minnesota, Vermont … 23 ○Appendix G: Minnesota Credit Calculator Memo … 27 ○Appendix H: New Hampshire’s Current Sweeping Credit Memo … 29 ○Appendix I: Example Credit Calculations …38 ○Appendix J: Commendation Letter from U.S. Environmental Protection Agency … 42 ○Appendix K: Ground Truthing Minnesota Data for New Hampshire, an Addendum to the Clean Sweep Technical Memo … 44 2 1. Executive Summary This technical memorandum summarizes the recommendations of an expert panel to update New Hampshire’s current Enhanced Street/Pavement Cleaning credit (USEPA 2017) and create a new measured credit for organic matter collection. The intention for these new and modified credits is to provide communities, consulting engineers, and technical assistance providers with the tools and incentives to reduce Total Nitrogen (TN) and Total Phosphorus (TP) loading associated with these nonstructural Best Management Practices (BMPs) under the National Pollutant Discharge Elimination System Stormwater Permit Program for NH (USEPA, 2017). Issued in January 2017, New Hampshire’s current Small Municipal Separate Storm Sewer System (MS4) General Permit (USEPA 2017) describes tracking and accounting metrics to quantify nutrient and sediment pollutant loading for different land uses. Under this permit, municipalities may earn TN or TP reduction credits through enhanced cleaning of impervious surfaces or by gathering, removing, and properly disposing of organic matter. However, these credits do not offer the sufficient return on the investment required to maintain such programs, and the current standard of street cleaning practice in the Great Bay Watershed is low (Town of Exeter 2015, University of Florida 2019). At the same time, a growing body of science suggests that enhanced street cleaning practices can achieve pollutant reductions far beyond what is currently recognized in New Hampshire’s existing credit programs (Tetra Tech 2020). Updates to the Great Bay Total Nitrogen General Permit and a new MS4 permit for New Hampshire are anticipated to include these credit options in the near future. Together, they represent opportunities for broadening the use of non-structural control credits. If accepted by state and federal regulators, the recommendations in this memorandum will 3 generate two options for obtaining credit for street cleaning under the state’s permits. Through the first option, permittees can receive credit by measuring the amount of organic matter collected throughout the year—an approach pioneered in Minnesota (Minnesota Pollution Control Agency 2022). The second option would allow permittees to use an updated version of the model that informs New Hampshire’s current Enhanced Street/Pavement Cleaning Program. This would offer credit for municipal sweeping efforts depending on the technology used, frequency of cleaning, seasonality, and location. Permittees could use either option to receive credit, but not both, within one reporting year. The U.S. Environmental Protection Agency, Region 1, has endorsed piloting these credits to provide insight into, and the adaptive improvement of current credits into the next New Hampshire and Massachusetts Small MS4 General Permits. Both options, but in particular the measured approach, would increase the amount of the credit permittees can earn through implementation of these BMPs beyond what is currently possible. By providing two options, the panel hopes to give permittees the flexibility they need to pursue credit in the way that best suits their objectives and resources, while creating incentives for them to conduct street cleaning when and where it will have the greatest water quality benefit. The interim between summer 2022 and the release of the new MS4 permit offers municipalities and the State of New Hampshire a unique opportunity to test these recommendations and collect data to assess their feasibility. As a result, the panel recommends that these proposed updates to New Hampshire's current credit programs be subject to adaptation when, and if, new science and data become available. They also offer a list of research topics that could support improvement of either credit in the future.(See Appendix B.) This memorandum was generated by the Clean Sweep Project, which used an expert panel process to develop consensus-based recommendations to modify pollutant load reductions for street cleaning BMPs in ways supported by existing science and data.(See Appendix C for an overview of Clean Sweep.)The project was modeled after Credit for Going Green, a similar initiative that used techniques from the Chesapeake Bay to develop pollutant reduction performance curves for using restored or constructed buffers to meet in-stream pollution reduction targets. Clean Sweep is sponsored by the U.S. Environmental Protection Agency, the Piscataqua Region Estuaries Partnership, and the Town of Durham, New Hampshire. The project team gratefully acknowledges the contributions of time and expertise from members of the 4 expert panel and advisory committee. 2. Definition of Terms This memorandum uses the following definitions for key terms. ●AF: Annual Frequency of sweeping. For example, if sweeping does not occur in December, January, or February, the AF would be 9 months /12 months, or 0.75. For year-round sweeping, AF would be 1 or something less than 1. ●Area:measured amount of street surface swept ●Credit:Estimated pollutant load reduction given for the application of BMPs, such as street cleaning, under the NPDES Stormwater Permit Program and other efforts to manage stormwater ●Credit sweeping:Amount of nutrient load removed by enhanced sweeping program (lbs/year) ●Delivery coefficient factor:Number between 0 and 1 that the measurement of collected TN or TP is multiplied by to account for natural attenuation of nutrients between the street and the receiving water body ●Dry mass:Mass of sweepings with all water removed, determined by oven drying a subsample and multiplying the wet mass of the sweeper load by the ratio of the dry mass to wet mass of the subsample ●Efficiency:Ability to decrease the nutrient load export rate ●IA swept:Area of impervious surface that is swept under the enhanced sweeping program (acres) ●Length (or lane miles) swept:Linear distance traveled by a sweeper with an assumed width of eight feet. ●Total Nitrogen concentration from mass:Ratio of TN to dry mass of sweepings, expressed in mg/kg and taken from the 25th percentile of the Minnesota data set ●NLER IC-land use:Nitrogen (TN) Load Export Rate for impervious cover and specified land use (lb/acre/yr) (Table 2-2) ●NRF sweeping:Nitrogen (TN) Reduction Factor for sweeping based on sweeper type and frequency (Table 2-4) ●Percent moisture:Mass of water divided by total wet mass of subsample. ●Performance:Ability of a Best Management Practice (BMP), such as street cleaning, to remove TN, TSS, and/or TP ●Phosphorus concentration from mass:Ratio of phosphorus to dry mass of sweepings, expressed in mg/kg and taken from the 25th percentile of the Minnesota data set 5 ●PLER IC-land use:Phosphorus (TP) Load Export Rate for impervious cover and specified land use (lb/acre/yr)(Table 2-1) ●PRF sweeping:Phosphorus (TP) Reduction Factor for sweeping based on sweeper type and frequency (Table 2-4) ●Sweeper width:Measurement of a street sweeper from side to side, often assumed to be eight feet ●Wet mass:Raw mass of street sweepings, including any moisture 6 3. About the Expert Panel and Its Process Clean Sweep applied the FAST expert panel process (Houle et al., 2019), which creates a structure to synthesize the opinions of a group of authorities on a subject around which there had been uncertainty due to insufficient and/or unattainable data because of physical constraints or lack of resources. This panel included state and regional regulators, experts in the field of watershed hydrology and stormwater management, a stormwater consultant, and representatives of New Hampshire and Massachusetts municipalities. The panel’s focus and work was guided by an advisory committee, which was comprised of similar stakeholders, including some from Vermont and Minnesota.(For an overview of panelists and advisory committee members and their roles in the Clean Sweep project, see Appendix D.) The advisory committee’s charge to the panel was to characterize street sweeping and leaf collection as separate best management practices (BMPs) for reducing nutrient loading in urban stormwater runoff; identify which aspects of these BMPs overlap in practice and in terms of current crediting in New Hampshire; and ultimately make recommendations to update these programs in keeping with existing science and in support of communities getting maximum, appropriate credit for these practices. The panel was supported by a core team, which provided technical guidance and support for project coordination, facilitation, and product development. To meet their charge, panelists reviewed and enhanced a synthesis of relevant literature and emerging regulatory strategies in Wisconsin, Vermont, and Minnesota (see Appendix E), and compared the crediting programs in these states (see Appendix F). Ultimately, they determined that New Hampshire’s current crediting approaches did not offer sufficient incentive for robust and effective street cleaning programs, and there was significant opportunity for change based on existing science. The panel held six meetings to assess potential changes and make recommendations for change. These discussions, as well as further review of additional scientific and regulatory resources, helped them identify potential modifications to New Hampshire’s current street sweeping program that would allow permittees to fulfill the upper boundaries of performance and therefore be eligible for maximum credit under New Hampshire’s MS4 permit. They also provided guidance for adapting the organic matter collection credit pioneered in Minnesota (Minnesota Pollution Control Agency 2022) for use in New Hampshire. 7 4. Key Decisions The options for credit recommended in this memorandum reflect panel decisions related to topics for which there was sufficient existing data, as well as others for which further research or data collection may be warranted. This section provides an overview of these decisions. 1. Create two options for permittees:The panel recommended adapting New Hampshire’s current Enhanced Street/Pavement Cleaning credit and establishing a new measured credit for organic matter collection. This decision was based on deliberations of the merits and limitations of both approaches and the ways they overlap. While the measured approach presented the prospect of significantly more credit, to apply it in New Hampshire would rely on practices unfamiliar to its communities and would, initially, be based on Minnesota data. The more familiar, model-based option offers little credit as written, however, the panel saw opportunities to change the model’s parameters and increase the amount of credit allowable. Ultimately, they felt having two options would give communities the flexibility to design street cleaning programs to meet their objectives and resources. 2. Use Minnesota’s Street Sweeping Credit Calculator as the basis to develop a similar program in New Hampshire.Minnesota’s program was a compelling model for three primary reasons. It is based on a rigorous study conducted by Tetra Tech and the University of Minnesota (Hobbie et al., 2020); results of this study have been integrated into the state’s stormwater program (Minnesota Pollution Control Agency 2022); and the state is working with permittees to facilitate its implementation. This provided enough of a foundation to pilot a version of this approach in New Hampshire. The only significant difference would be to omit the modeling option outlined in Minnesota’s approach, given the panel’s decision to adapt New Hampshire’s model-based, street cleaning credit. 3. Use Minnesota data to develop a measured credit:Given the lack of relevant data from New Hampshire, the panel assessed the feasibility of using data from Minnesota’s Developing a Street Sweeping Credit for Stormwater Phosphorus Source Reduction Final Report (Hobbie et al., 2020) as a basis for the credit. In response to sample calculations using this data for frequent sweeping (19 times annually) and infrequent sweeping (four times annually in times of high deposition), the panel was concerned that awarding more credit for infrequent collection could disincentivize more frequent collection. However, they appreciated the caution inherent in Minnesota’s conservative use of the 25th percentile TP and TN concentrations (as opposed to, for example, the median or mean) in collected organic material to estimate TP and TN recovered through sweeping. Given the low standard of practice in New Hampshire, they thought the suggested interval for infrequent collection would be an improvement. Ultimately, they felt comfortable starting 8 with Minnesota data, but underscored it would be important to assess data collected by New Hampshire communities piloting this approach. 4.Do not use a delivery coefficient factor in New Hampshire’s measured credit program.A primary concern was related to the fate in transport of TN or TP. The current assumption in the Minnesota approach is that all TP removed from the street would have reached receiving waters. There is no science to fully describe this dynamic in New Hampshire, and several panelists felt this assumption could lead to over crediting, i.e., not all TN and TP in collected organic matter was destined for receiving waters. To balance concerns about over crediting in their state, Minnesota adopted conservative loading rates, using the 25th percentile, rather than a mean or median concentration of TP, in collected organic material. This decision was sufficiently cautious for the panel not to recommend the application of a delivery coefficient factor—a multiplier less than one to account for TN and TP in collected organic matter that would not reach receiving waters—for New Hampshire. 5.Allow for a range of acceptable technologies in the current, model-based street cleaning credit:The panel agreed that a range of technologies should be allowable in the updated credit, and that a mechanical sweeper represented minimal effort and the use of additional technology, e.g., a vacuum assisted sweeper, should be recognized as a maximum effort. This decision reflected the panel’s focus on making changes consistent with the different goals and resources of communities. 6.Identify a minimum, medium, and maximum sweeping effort in the current, model-based street cleaning credit:The panel defined 1) minimum effort as sweeping at least two times annually (as in the current credit); 2) medium effort as sweeping every other week in the fall (September to December); and 3) maximum effort as monthly sweeping with weekly sweeping in the fall (September to December) and early spring. 7.Simplify the location parameter and accommodate seasonal changes in TN and TP loading in the model-based street cleaning credit:The panel recommended using medium density residential impervious cover (IC) land use to generate a pollutant load to which to apply the NRF/PRF value. They believe this represents the majority of land use available for sweeping in most New Hampshire communities. For seasonal leaf collection (i.e., intensive weekly sweeping in times of high organic material deposition), the panel recommended an additional 10% removal factor—a 5% increase over the existing enhanced leaf collection credit— to better reflect removals demonstrated in recent literature (Tetra Tech 2020). 9 5. New: Measured Organic Matter Collection Credit Municipal responsibility Permittees who choose to use this approach would receive credit for organic matter that is collected from impervious surfaces. Under the proposed credit, they would have the option for tracking TN and TP reductions from street sweeping activities with some ability to use locally derived data (see calculation steps below). These were adopted from the approach developed and used in Minnesota.(See Appendix G for a summary of Minnesota’s approach.) How credit would be calculated (For example credit calculations, see Appendix I.) Step 1)Determine the dry mass of sweeping matter collected, using Equation 1. Equation 1: 𝐶𝑘𝑦 𝐿𝑎𝑘𝑘 (𝑘𝑎) = 𝑊𝑎𝑘 𝐿𝑎𝑘𝑘 (𝑘𝑎) ∗ (1 − 𝑃𝑎𝑘𝑎𝑎𝑘𝑘 𝐿𝑘𝑖𝑘𝑘𝑘𝑘𝑎 𝐶𝑘𝑘𝑘𝑎𝑘𝑘 ) If percent moisture content is known, it may be input into Equation 1 in decimal form, otherwise apply a seasonally averaged percent moisture content developed from the University of Minnesota dataset for the appropriate season (Table 1). Step 2)Determine the TN or TP load removed by multiplying the dry mass determined in Step 1 and the seasonal TN or TP concentration, using Equation 2. Equation 2: TN or TP Removed (lb) =Concentration (mg/kg) 1 x 10 -6𝐶𝑘𝑦 𝐿𝑎𝑘𝑘(𝑘𝑎 ∗ 𝑅𝐿 𝑘𝑘 𝑅𝑃 ∗ Apply the TN or TP concentration from the University of Minnesota dataset for the appropriate season (Table 1). Table 1 Season Average Moisture Content TP Concentration from Mass (mg/kg) TN Concentration from Mass (mg/kg) Fall (Sept - Dec)0.48 857 2,762 Non-fall (Jan - Aug)0.22 414 994 10 6. Update to Current Model-Based Street Cleaning Credit New Hampshire’s current Enhanced Street/Pavement Cleaning credit was introduced in Appendix F of New Hampshire’s (USEPA 2017) and Massachusetts’ (USEPA 2016) MS4 permits. (See Appendix H for a synthesis of New Hampshire’s program.)The panel recommends the following modifications to New Hampshire’s current credit: ●Municipalities track and receive credit for area or lane miles swept, sweeper type, and sweeping frequency. (The current credit requires municipalities to also track land use in the watershed area swept.) ●Adopt medium density residential land use loading values for IC and add an option for tracking lane miles. If permittees can differentiate area and land use, those values could be utilized. (See Tables 3-1 and 3-2 in Appendix F and Attachment 3 of New Hampshire’s MS4 permit.) For those who lack this capacity, the panel recommends the default medium density residential land use as it represents most of the potential sweeping routes. ●Municipalities can use mechanical broom and vacuum sweepers, which include true vacuum, vacuum assisted, and regenerative air sweepers. (The current credit includes three technology options.) ●Municipalities can use one of two options for sweeping frequency to characterize minimum and maximum effort. (See Table 3). (The current credit has three frequency options.) How credit would be calculated (For example credit calculations, see Appendix I.) Under this modified version of New Hampshire’s Enhanced Street/Pavement Cleaning Program, permittees could earn a TN and TP reduction credit for conducting a municipal sweeping program. The credit would calculated by using the following equations and values in Table 3: Equation 3: Credit TP Sweeping (lb/yr) = 𝐼𝑘𝑘𝑎𝑘𝑘𝑖𝑘𝑘𝑘 𝐴𝑘𝑎𝑎 (𝑎𝑎) ∗ 𝑅𝑃 𝐿𝑘𝑎𝑎 𝑅𝑎𝑎𝑘𝑎𝑘𝑖𝑘𝑘 𝐶𝑎𝑎𝑘𝑘𝑘 (𝑃𝑅𝐶) 𝑘𝑎 𝑅𝑘𝑎𝑎𝑘𝑎𝑘 𝑅𝑦𝑘𝑎 ∗ 𝑃𝐿𝐶𝑅 𝐼𝐶 𝑘𝑎𝑘𝑎 𝑘𝑘𝑎 (𝑘𝑎/𝑎𝑎/𝑦𝑎𝑎𝑘) Equation 4: Credit TN sweeping (lb/yr) = 𝐼𝑘𝑘𝑎𝑘𝑘𝑖𝑘𝑘𝑘 𝑎𝑘𝑎𝑎 (𝑎𝑎) ∗ 𝑅𝐿 𝐿𝑘𝑎𝑎 𝑅𝑎𝑎𝑘𝑎𝑘𝑖𝑘𝑘 𝐶𝑎𝑎𝑘𝑘𝑘 (𝐿𝑅𝐶) 𝑘𝑎 𝑅𝑘𝑎𝑎𝑘𝑎𝑘 𝑅𝑦𝑘𝑎 ∗ 𝐿𝐿𝐶𝑅 𝐼𝐶 𝑘𝑎𝑘𝑎 𝑘𝑘𝑎 (𝑘𝑎/𝑎𝑎/𝑦𝑎𝑎𝑘) 11 PRF/NRF credits range from a minimum effort (0.01 - 0.02) to a medium effort (0.15), and a maximum effort (up to 0.25) depending on the municipal program approach. Table 3: Updated Parameters for New Hampshire’s Model-based Credit for Street Cleaning Parameter Minimum Effort Medium effort Maximum Effort Frequency Up to 2 times per year in any season. NRF/PRF = 0.01 for a mechanical sweeper and 0.02 for a vacuum. Every other week in the fall (Sept. to Dec.). NRF/PRF = 0.15 Monthly routine maintenance with more intensive (weekly) in Fall (Sept. to Dec.) and early spring. NRF/PRF = 0.25 with enhanced leaf collection. Assumes a vacuum sweeper (defined above), but may be combined with other efforts. Location and seasonality To accommodate seasonal increases in TN and TP and simplify the location parameter: 1)Use medium density residential IC land use, which integrates the majority of likely land uses. 2)For intensive (weekly) fall sweeping in times of high organic material deposition, offer a 10% additional removal factor. This is a 5% increase over the enhanced leaf collection credit in the current model and better reflects removals in the recent literature. (Synonymous with maximum effort.) For the area conversion from lane miles, sweeper width is assumed to be eight feet. This method, since it is based on the least informative inputs, is necessarily conservative and will likely result in less credit than the measured approach. 7. Considerations When Applying the Credits The relationship between seasonality and nutrient loading has been incorporated in the measured approach based on recent research from the U.S. Geological Survey and University of Minnesota (Selbig 2016, Hobbie et al., 2020). This work demonstrated a pronounced difference in moisture content and TN and TP concentration depending on the season. 12 The measured approach is designed to represent two periods of street sweeping throughout the year: fall leaf collection and non-fall collection. The current model-based approach does not differentiate between seasons and is likely too conservative. Adoption of the proposed measured organic collection credit and updated model-based street cleaning credit will allow permittees more flexibility in reporting and potentially greater accuracy when leaf collection is a major component of sweeping. Clean Sweep partners will pilot the measured approach in New Hampshire communities in 2022 and 2023. The U.S. Environmental Protection Agency has commended the recommendations and the Clean Sweep approach. In a letter dated August 15, 2022, they observed: “The piloting of these methods will provide insight and adaptive improvement of the new credits and offer opportunities to validate the approaches for future use throughout New England. Information gained during the piloting of the new credits could allow EPA R1 to integrate these credits, or an iteration of these credits, into the next New Hampshire and Massachusetts Small MS4 General Permits.”(See Appendix J.) 8. Appendices ●Appendix A: References … 13 ●Appendix B: Suggested Areas of Future Research … 15 ●Appendix C: Clean Sweep Overview … 17 ●Appendix D: Clean Sweep Roles, Responsibilities, Timeline … 18 ●Appendix E: Clean Sweep Synthesis of Literature and Other Resources … 20 ●Appendix F: Summary of Credit Programs in New Hampshire, Minnesota, Vermont … 23 ●Appendix G: Minnesota Credit Calculator Memo … 27 ●Appendix H: New Hampshire’s Current Sweeping Credit Memo … 29 ●Appendix I: Example Credit Calculations … 38 ●Appendix J: Commendation Letter from U.S. Environmental Protection Agency … 42 ●Appendix K: Ground Truthing Minnesota Data for New Hampshire, an Addendum to the Clean Sweep Technical Memo … 44 13 The measured approach is designed to represent two periods of street sweeping throughout the year: fall leaf collection and non-fall collection. The current model-based approach does not differentiate between seasons and is likely too conservative. Adoption of the proposed measured organic collection credit and updated model-based street cleaning credit will allow permittees more flexibility in reporting and potentially greater accuracy when leaf collection is a major component of sweeping. Clean Sweep partners will pilot the measured approach in New Hampshire communities in 2022 and 2023. The U.S. Environmental Protection Agency has commended the recommendations and the Clean Sweep approach. In a letter dated August 15, 2022, they observed: “The piloting of these methods will provide insight and adaptive improvement of the new credits and offer opportunities to validate the approaches for future use throughout New England. Information gained during the piloting of the new credits could allow EPA R1 to integrate these credits, or an iteration of these credits, into the next New Hampshire and Massachusetts Small MS4 General Permits.” (See Appendix J.) 8.Appendices ●Appendix A: References … 13 ●Appendix B: Suggested Areas of Future Research … 15 ●Appendix C: Clean Sweep Overview … 17 ●Appendix D: Clean Sweep Roles, Responsibilities, Timeline … 18 ●Appendix E: Clean Sweep Synthesis of Literature and Other Resources … 20 ●Appendix F: Summary of Credit Programs in New Hampshire, Minnesota, Vermont … 23 ●Appendix G: Minnesota Credit Calculator Memo … 27 ●Appendix H: New Hampshire’s Current Sweeping Credit Memo … 29 ●Appendix I: Example Credit Calculations … 38 ●Appendix J: Commendation Letter from U.S. Environmental Protection Agency … 42 12 Appendix A: References United States Environmental Protection Agency (EPA), 2017. Appendix F, Attachment 2 . New Hampshire Small MS4 General Permit: Enhanced Street/Pavement Cleaning Credit. https://www.epa.gov/npdes-permits/new-hampshire-small-ms4-general-permit United States Environmental Protection Agency (EPA), 2017. National Pollutant Discharge Elimination System (NPDES) Permit Program for New England. https://www.epa.gov/npdes-permits/npdes-stormwater-permit-program-new-england United States Environmental Protection Agency (EPA), 2017. New Hampshire Small MS4 General Permit. https://www.epa.gov/npdes-permits/new-hampshire-small-ms4-general-permit Town of Exeter, 2015. Total Nitorgen Control Plan Annual Report for 2015 https://www.exeternh.gov/sites/default/files/fileattachments/public_works/page/12771/exeter _nh_-_2015_annual_tn_report_aoc_13-010_0.pdf University of Florida, 2019. Municipal Separate Storm Sewer System (MS4) Practices Assessment Phase III—Reclaimed Water Areas Final Report To Florida Department of Environmental Protection https://www.florida-stormwater.org/assets/FSAEF/Research/MS4/UF%20FDEP%20MS4%20Mai ntenance%20Final%20Report_edited.pdf Tetra Tech, 2020. Memo: Street Sweeping Pollutant Reductions and Crediting. https://docs.google.com/document/d/1YF-zXm4gQ-Xo0a_2Vy68pqQdk-ylego7/edit Tetra Tech, 2020. Memo: Leaf Litter Management. https://docs.google.com/document/d/1LTMakd3j6AUyHZwAv5Dbfu4dzWaIwl5l/edit Houle, James, Riley, C., Leonard, D., 2019. FAST: Expert Process for Decision Making. https://drive.google.com/file/d/1MKTaWME_0Lkuh-grxTUjWJyDD13w-2fx/view?usp=sharing Hobbie, Sarah, King, R, Belo, T, Baker, L, Finlay, J, 2020. Developing a Street Sweeping Credit for Stormwater Phosphorus Source Reduction. https://www.wrc.umn.edu/developing-street-sweeping-credit-stormwater-phosphorus-source-r eduction 13 United States Environmental Protection Agency (EPA), 2016. Massachusetts Small MS4 General Permit.https://www.epa.gov/npdes-permits/massachusetts-small-ms4-general-permit Selbig, William, 2016. “Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater,” Science of the Total Environment. https://drive.google.com/file/d/1IK7Qgp25Lta3Uy008PeOOlx6ZFzAK-X-/view 14 Appendix B: Suggested Areas of Future Research Ground truth Minnesota data for New Hampshire:The panel recommends pilot studies with a level of analysis sufficient to validate that data collected in New Hampshire for percent moisture and other variables are consistent with those used for Minnesota’s calculations. Citizen collection programs & loading:Both the expert panel and the advisory committee acknowledge growing interest in, and adoption, of leaf bagging and composting programs and other citizen-based efforts. Given the panel’s focus on municipal street cleaning, this was beyond its purview. However, the panel feels there is value in synthesizing science and data to support the contribution of such programs to load reductions in relation to street cleaning efforts. In relation to this, the panel suggested studies to better characterize the relative loading from different types of landscapes and impervious cover. Nutrient loading rates associated with different land uses:The panel recommends studies to better characterize the nutrient loading rates associated with different land uses in general, and in different seasons. Tree canopy:The extent and composition of tree canopy can influence the nutrient load associated with organic matter deposition. For example, areas where the canopy is more extensive may contribute to higher nutrient loads. Likewise, different tree species may be associated with higher loading, or they may drop their leaves at different times, which could influence appropriate timing of collection. While there is relevant research underway and municipal capacity for canopy assessment is increasing, the panel did not feel that science currently existed to support the integration of this into recommendations in this report. Research questions to help address could include the following: ●How does the extent of canopy influence potential nutrient loading? ●How do different tree species (and composition of canopy) influence potential nutrient loading? ●What are the influences of climate change on the leaf drop of representative tree species in New Hampshire? Lane miles:The panel considered whether the width of lane miles used in the current model-based street sweeping credit adequately reflected the potential nutrient loading and therefore potential credit. However, new data and more modeling would be required to decide whether, for example, the width could be expanded to represent a greater area or whether parking restrictions should be coordinated with sweeping. 15 Seasonality:The panel acknowledged that the concentration embedded in the current model-based street sweeping credit was based on data that wasn’t entirely collected in the fall, and that seasonality is not represented well. Future versions of the model could address this with new data and more modeling. Location of sweeping and phosphorus loading:The release of legacy phosphorus from retention ponds is a growing issue. Research is underway to clarify whether sweeping upstream of those ponds can remove sources of phosphorus that would otherwise wash into the pond. If so, the efficiency of ponds should be adjusted to account for less phosphorus available for removal. Relative loading by watershed type:Panelists suggested there was potential for enrichment factors for base loading rates to be created for different watershed types based on existing data from Minnesota and Wisconsin. 16 Clean Sweep This project will develop consensus-based recommendations for pollutant load reductions for street sweeping BMPs. Our goal is to ensure that the credit received under regulatory permits issued by the NPDES Stormwater Permit Program is commensurate with the latest science. The team will develop a technical memorandum and other outreach products to share these recommendations with communities, regulators, consultants, and others in the Piscataqua Region Watershed in fall 2022. Why this project Urban stormwater is one of the fastest growing sources of pollution in communities nationwide. In New Hampshire, local governments have raised concerns about meeting pollutant reduction goals for total nitrogen (TN), total phosphorus (TP), and total suspended solids (TSS). Street sweeping and seasonal leaf collection are nonstructural best management practices (BMPs) that historically have received inconsistent pollutant removal credit under regulatory permits. However, recent science and data indicate these BMPs may be much more effective at removing pollutants than previously expected, especially at certain times of the year. This project will provide regulators and communities with science-based recommendations to quantify the water quality benefits of these BMPs. Our approach We will use the expert panel process FAST, an iterative, weight-of-evidence approach to synthesizing expert opinion and reaching general agreement around science based recommendations for resource management. This process was refined in the Credit for Going Green project, which devel- oped pollutant reduction performance curves for restored or constructed buffers,so that they could receive pollutant removal credits under New Hampshire’s regulatory permits. This process will be supported by an advisory committee, composed of municipal representatives, regulators, and consul- tants, as well as an expert panel of scientists in the fields of hydrology, fate and transport of urban pollutants, and engineering. Contact James Houle Director, UNHSC 603-767-7091 james.houle@unh.edu Abigail Lyon Community Technical Assistance Program Manager, PREP (603) 862-3729 Abigail.Lyon@unh.edu This project is sponsored by the US Environmental Protection Agency, PREP, and the Town of Durham, N.H. Project partners University of New Hampshire Stormwater Center (UNHSC) Piscataqua Region Estuaries Partnership (PREP) Roca Communications Advisors New Hampshire Department of Environmental Services United States Environmental Protection Agency Region 1 City of Dover (and municipalities to be determined) Consultant Engineers Appendix D: Clean Sweep Roles, Responsibilities, Timeline Participant Role Responsibilities Core Team James Houle, Director, University of New Hampshire Stormwater Center Technical lead, panel chair Oversee advisory engagement of committee and expert panel, development of products, and sharing of results Abigail Lyon, Technical Assistance Program Manager, Piscataqua Region Estuaries Partnership Project lead, fiscal agent Oversee additional stakeholder engagement, project budget, and reporting Elizabeth Buschert, Project Manager, University of New Hampshire Stormwater Center Technical support Conduct literature analysis, develop synthesis, and provide technical support Dolores Leonard, Principal Roca Communications Group process, products Support core team in convening and facilitating advisory committee and expert panel and in developing final products. Lola Jalbert Combs, Assistant Producer, Roca Communications Meeting support, products Support core team in convening and facilitating advisory committee and expert panel and in developing final products Advisory Committee:Frame questions for panel, suggest panelists, provide feedback on progress and input on final products. Participation includes three virtual meetings and responding to email requests for input. Up to 10 hour time commitment. Bill Boulanger, Deputy Director of Community Services, City of Dover, N.H. Committee member Advise on municipal level needs, interests, and applicability David Bowley, Utilities Systems Manager, University of New Hampshire Committee member Advise on needs, interests, and applicability within a large scale, non municipal setting. Zach Henderson, Water Resources Technical Manager, Woodard & Curran Committee member Advise on BMP design and implementation Caroline Kendall, Town Administrator, Town of Rollinsford, N.H. Committee member Advise on municipal level needs, interests, and applicability James McCarty, GIS Manager, City of Portsmouth, N.H.Committee member Advise on municipal level needs, interests, and applicability Randy Neprash, Stantec, National Municipal Stormwater Association Committee member Advise on municipal level needs, interests, and applicability, as well as credit design & implementation in other regions. James Pease,Analyst-Biologist, VT Dept. of Environmental Conservation Committee member Advise on state level policy interests and perspectives Sally Soule, Coastal Watershed Supervisor, N.H. Dept. of Environmental Services Committee member Advise on state level policy interests and perspectives April Talon, Town Engineer, Town of Durham, N.H.Committee member Advise on municipal level needs, interests, and applicability 18 Newton Tedder, U.S., Environmental Engineer, MS4 Permit Writer, U.S. Environmental Protection Agency, Region 1 Committee member Advise on federal level policy interests and perspectives Michelle Vuto, Environmental Engineer, U.S. Environmental Protection Agency, Region 1 Committee member Advise on federal level policy interests and perspectives Participant Role Responsibilities Expert Panel:Develop science-based recommendations to inform changes to NH’s approach to crediting street weeping and/or leaf collection. Bill Boulanger, Deputy Director of Community Services, City of Dover, N.H. Panelist Provide firsthand experience with application of BMPs at municipal scale and perspectives on changes to these BMPs considered by the panel. Ted Diers, Administrator, N.H. Dept. of Environmental Services Panelist Provide perspective on state level policy interests and perspectives Sarah Hobbie, Distinguished McKnight University Professor, Dept. of Ecology, Evolution, and Behavior, University of Minnesota Panelist Provide scientific expertise and understanding on how changes to BMPs could impact water quality impacts James Houle, Director, University of New Hampshire Stormwater Center Panel Chair Provide perspective on engagement of committee and expert panel, development of products, and sharing of results, James McGonagle, Commissioner of Public Works, Newton, MA Panelist Provide firsthand experience with application of BMPs at municipal scale and perspectives on changes to these BMPs considered by the panel. Theresa McGovern, Director of Water Resources at VHB Panelist Provide firsthand experience with application of BMPs and to the extent possible, changes to these BMPs considered by the panel. Bill Selbig, Research Hydrologist,Upper Midwest Water Science Center Panelist Provide scientific expertise and understanding on how changes to BMPs could impact water quality impacts Sally Soule, Coastal Watershed Supervisor, N.H. Dept. of Environmental Services Committe e member Provide perspective on state level policy interests and perspectives Mark Voorhees, Environmental Engineer, U.S. Environmental Protection Agency, Region 1 Panelist Provide perspective on federal level policy interests and perspectives Michelle Vuto, Environmental Engineer, U.S. Environmental Protection Agency, Region 1 Panelist Provide perspective on federal level policy interests and perspectives Gretchen Young, Environmental Projects Manager, City of Dover, N.H. Panelist Provide firsthand experience with application of BMPs at municipal scale and perspectives on changes to these BMPs considered by the panel. 19 Timeline 20 Appendix E: Clean Sweep Synthesis of Literature and Other Resources Tetra Tech Literature Reviews ●Street sweeping:extended /summary ●Leaf collection:extended /summary New Hampshire Resources ●Integrated memo on NH leaf collection & street sweeping crediting programs. ●Total Maximum Daily Load (TMDL) Report for 44 Bacteria Impaired Waters in New Hampshire ●Joint Adaptive Management Plan Vermont Resources ●Vermont crediting information ●Vermont literature review ●Clean Sweep Webinar:Recording.Presentation:Vermont Clean Streets ●VT ski soils and runoff on page 72. It states: “Both logging and ski slopes were assumed to have a curve number equivalent to lawn in fair condition. Thus, for B/C soils, the equivalent curve number would be 74.” ●Study from S Burlington. The issue with this study is that the P-load calculated from the measured leaf mass was close to the TMDL target for the City (114 vs 135) and if we added in the CB cleaning they would meet the target using the current practices. ●Sorenson, J.R., Pease, J.M., Foote, J.K., Chalmers, A.T., Ainley, D.H., and Williams, C.J., in review, Estimated Phosphorus Load Reductions from Leaf Litter Removal in the Lake Champlain drainage area, Vermont: U.S. Geological Survey Scientific Investigations Report 2021–####, 50 p. ●Sorenson, J.R., Pease, J.M., Foote, J.K., Chalmers, A.T., Ainley, D.H., and Williams, C.J., in review, Data supporting phosphorus load-reduction estimates from leaf-litter removal in central and northwestern Vermont: U.S. Geological Survey data release, Minnesota Resources ●Street Sweeping: Minnesota Stormwater Manual ○Street Sweeping SOP ●Street Sweeping Phosphorus Credit Calculator: User Guide - Minnesota Stormwater Manual 21 ●Developing a Street Sweeping Credit for Stormwater Phosphorus Source Reduction ●Minnesota Street Sweeping Phosphorus Load Credit Development ●Clean Sweep Webinar:Recording. Presentations:Minnesota Street Sweeping ●Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater (Summer phosphorus concentration estimates from residential areas detailed in Figure 3) Massachusetts ●USGS report looking at materials on streets before and after regenerative-air removal of 32 elements (including total P) in Cambridge, MA Wisconsin resources ●Interim Municipal Phosphorus Reduction Credit for Leaf Management Programs ●Evaluation of leaf removal as a means to reduce nutrient concentrations and loads in urban stormwater ●Reducing Leaf Litter Contributions of Phosphorus and Nitrogen to Urban Stormwater through Municipal Leaf Collection and Street Cleaning Practices ●Leachable phosphorus from senesced green ash and Norway maple leaves in urban watersheds ●Roger Bannerman's data analysis on lawns as a source of phosphorus ●Reducing Leaf Litter Contributions of Phosphorus and Nitrogen to Urban Stormwater through Municipal Leaf Collection and Street Cleaning Practices (Selbig). Rhode Island resources ●Analysis performed on behalf of RIDOT to evaluate cost-effectiveness of sweeping vs. structural controls General ●World Sweeper ●Adopt-A-Drain ●Leave the Leaves to Benefit Wildlife | Xerces Society 22 Appendix F: Summary of Credit Programs in New Hampshire, Minnesota & Vermont Calculating Credit: What is the Best Option for New Hampshire? February 11, 2022 Why this Memo? This memo is intended to support the Clean Sweep Advisory Committee's discussion of the pros and cons of a model-based or measured approach to assigning credit for a new BMP focused on organic matter removal. This memo compares the municipal responsibilities and calculation methods for New Hampshire’s current model-based approach with Minnesota’s Street Sweeping Credit Calculator—which gives municipalities the option to use a measured approach—and the new approach used in Vermont. The memo also provides a comparison of the credits that theoretically would be awarded for each approach using data collected in Minnesota. I.Minnesota’s Street Sweeping Credit Calculator Municipal responsibility Municipalities have three options to track phosphorus reductions from street sweeping: 1.Measure dry mass of sweepings and either record season swept or measure organic matter content 2.Measure wet mass of sweepings and record either season swept or report some combination of season swept, organic matter content, and percent moisture 3.Track lane miles swept How credit is calculated In the first two scenarios, phosphorus removal is calculated using the following equations: ●Phosphorus Removed = Dry Mass * Phosphorus Concentration from Mass (mg/kg) ●Dry Mass (lb) = Wet Mass (lb) * 100/ (Dry Basis Moisture Content + 100) Values for average seasonal percent moisture and phosphorus concentration are taken from University of Minnesota (UNM) study data in Table 1 below. (Note: this is not average P concentration, but rather the 25% percentile P concentration, making this a conservative estimate of P removal.)This reflects the distinct differences in moisture content and 23 phosphorus concentration the UMN study found in sweepings collected during fall leaf drop and those collected the rest of the year. Fall designation is not month-specific, which allows for reporting of leaf collection whenever leaf drop occurs. Table 1 Season Average Percent Moisture Phosphorus Concentration from Mass (mg/kg) Fall 0.48 857.0 Non-fall 0.22 413.6 In the last scenario (lane miles swept), phosphorus removal is calculated using this formula: Phosphorus Removed = Length Swept * Sweeper Width * Areal Phosphorus Removal Sweeper Width is assumed to be 8.5 feet and Areal Phosphorus Removal (APR) is set at 0.00017 pounds per acre per pass. (Note:the APR is set based on the P8 model.)The set APR value was derived from 10 years of simulated street sweeping in a Minnesota community. This method, since it is based on the least informative inputs, is necessarily conservative and will likely result in the smallest amount of credit. II.New Hampshire Modeling Method for Sweeping & Leaf Collection Municipal responsibility Municipalities must track area swept, land use, sweeper type, and sweeping frequency. How credit is calculated Under the New Hampshire Enhanced Street/Pavement Cleaning Program, permittees may earn a phosphorus or a nitrogen reduction credit for conducting an enhanced cleaning program of impervious surfaces. The credit is calculated by using the following equations: ●Credit P sweeping (lb/year) =impervious area swept (acres) * P load export rate of land use (lb/acre/year) * P reduction efficiency factor of sweeper type * annual frequency ●Credit N sweeping (lb/year) =impervious area swept (acres) * N load export rate of land use (lb/acre/year) * N reduction efficiency factor of sweeper type * annual frequency Technology allowed include mechanical broom sweepers, vacuum assisted sweepers, and high-efficiency regenerative air-vacuums. Sweeping frequency can be twice annually (spring & fall), monthly, or weekly. 24 Under New Hampshire’s Enhanced Organic Matter and Leaf Litter Collection Program, permittees may earn phosphorus and nitrogen reduction credits by performing regular gathering, removal, and proper disposal of landscaping wastes, organic debris, and leaf litter from impervious surfaces within applicable watershed areas (i.e., Lake Phosphorus Control Plan area or Great Bay watershed). The permittee may use an enhanced sweeping program (e.g., weekly) as part of earning this credit provided the sweeping is effective at removing leaf litter and organic material. Credit is calculated with these equations: ●Credit P leaf litter (lb/year) = (IA leaf litter acres) * P load export rate of land use (lb/acre/year) * 0.05 ●Credit N leaf litter (lb/year) = (IA leaf litter acres) * N load export rate of land use (lb/acre/year) * 0.05 To receive credit, municipalities gather and remove landscaping wastes, organic debris, and leaf litter from impervious roadways and parking lots at least once a week between September 1 and December 1 each year; immediately following any landscaping activities in the applicable watershed and at additional times necessary to ensure removal of all aforementioned materials at least once a week; and ensure disposal of these materials will not contribute pollutants to any surface water discharge.(More information about these credits and calculations are here.) III. VT Modeling Method for Sweeping* Municipal Responsibility Municipalities must track area swept, land use, watershed swept, percent tree canopy cover over sidewalks and streets, presence of curb and gutter, sweeping frequency, and sweeper type. How credit is calculated Permittees may earn phosphorus credit for street sweeping of impervious surfaces, calculated with the following formula: Credit P sweeping (lb/year) = area swept (acres) * P export rate for watershed and land use swept (lb/acre/year) * P reduction factor This P credit is only valid if the following conditions are met: ●Streets swept have curb and gutter ●Percent tree canopy cover of roads and sidewalks in the area swept is greater than 4% ●Streets are swept at least four times in the fall to pick up leaves 25 The P reduction factor is prorated based on the percent canopy cover of the area swept and the maximum credit given is 25% for areas with 40-45% canopy cover. * Vermont is updating their street sweeping credit but has not yet published a final report, this summary is our best understanding of their new guidelines but may not reflect all details. IV.Comparison In order to evaluate the difference between the calculation methods, a comparison was conducted using examples from the MN calculator training. These areas were then modeled according to the current NH crediting approach, outlined in appendix F of the NH MS4 permit. Results This exercise demonstrated large differences in pollutant load reduction between the modeled and measured approaches. All modeling results (NH, VT and MN) lead to much lower calculated reductions for total phosphorus. On the low end the measured results lead to 12-30 times more credit then the VT and NH methods respectively. On the upper end the measured results lead to 21-50 times more credit then the VT and NH methods respectively. We will discuss these methods and the differences in load reduction at the February 15 Clean Sweep Expert Panel Meeting. Example 1 (top): TP credits from sweeping activities on one 10 mile long, frequently swept sweeper route with 15% canopy cover using all three modeling approaches (New Hampshire’s current credit, Vermont’s new credit, and Minnesota’s option 3) as well as four variations of Minnesota’s measured approach. Example 2 (bottom): TP credit from a less frequently swept 22 mile long sweeper route with 22% canopy cover calculated using the same methods. 26 Appendix G: Summary of Minnesota’s Credit Calculator Minnesota Street Sweeping Credit Calculator Memo Updated July, 15, 2022 Why this Memo? This memo is intended to support the Clean Sweep Expert Panel as they consider the potential application of Minnesota’s Street Sweeping Credit Calculator in New Hampshire. It summarizes how credit is allocated according to the state’s user guide and this video. Minnesota municipalities have three options to track phosphorus reductions from street sweeping: 1.Measure dry mass of sweepings AND either record season swept or measure organic matter content 2.Measure wet mass of sweepings AND record either season swept OR report some combination of season swept, organic matter content, and percent moisture 3.Track lane miles swept In the first two scenarios, phosphorus removed is calculated using the following equations (also see flow chart on page 2): i)Phosphorus Removed = Dry Mass * Phosphorus Concentration from Mass (mg/kg) ii)Phosphorus Concentration = 0.044 + 0.0018 * Organic Matter % Dry Mass = (Wet Mass * 100)/(Dry Basis Moisture Content % + 100) Values for average percent moisture and phosphorus concentration from mass are taken from University of Minnesota (UNM) studyxx data in Table 1. This reflects the distinct differences in moisture content and phosphorus concentration the UMN study found in sweepings collected during fall leaf drop and sweepings collected during the rest of the year. Table 1 Season Dry Basis Moisture Content (%)Phosphorus Concentration from Mass (mg/kg) Fall 90.46 857.0 Non-fall 27.76 413.6 27 ●Note the NH adaptation to the MN method uses average seasonal Percent Moisture content converted from the Dry Basis Moisture Content as Percent Moisture content is a more commonly used measure. The fall designation is flexible rather than month-specific, which allows for reporting of leaf collection whenever the autumn leaf drop occurs. In the last scenario phosphorus removed is calculated using the formula Phosphorus Removed = Length Swept x Sweeper Width * Areal Phosphorus Removal Where Sweeper Width is assumed to be 8.5 feet and Areal Phosphorus Removal (APR) is set at 0.00017 pounds per acre per pass. The set APR value was derived from 10 years of simulated street sweeping in a Minnesota community using the P8 model. This method, since it is based on the least informative inputs, is necessarily conservative and will likely result in the smallest amount of credit. 28 Appendix H: Summary of New Hampshire’s Current Street Sweeping Credit New Hampshire Enhanced Street/Pavement Cleaning & Leaf Collection Credit Memo Revised 11/1/21 Why this Memo? This memo is intended to support deliberations of the Clean Sweep Expert Panel by summarizing how credit is allocated under New Hampshire’s Enhanced Street/Pavement Cleaning and Organic Matter and Leaf Litter Collection programs. Contents I.Street Sweeping/Pavement Cleaning Program Summary A. Factors influencing Credit B. Example Credit Calculations C. Questions for the Panel II.Organic Matter & Leaf Litter Collection Program Summary A.Factors Influencing Credit B.Example Credit Calculations C.Associated Street/Pavement Cleaning Credit III.Tables: 2-1, 2-2, & Consolidated I. Street Sweeping Credit Program Summary Under the New Hampshire Enhanced Street/Pavement Cleaning Program, permittees may earn a phosphorus (Table 2-1)or a nitrogen reduction credit (Table 2-2)for conducting an enhanced cleaning program of impervious surfaces. The credit is calculated by using the following equations: ●Equation 2-1:Phosphorus Credit P sweeping = IA swept * PLER IC-land use * PRF sweeping * AF ●Equation 2-2:Nitrogen Credit N sweeping = IA swept * NLER IC-land use * NRF sweeping * AF 29 Definition of Terms ●Credit sweeping:Amount of nutrient load removed by enhanced sweeping program (lbs/year) ●IA swept:Area of impervious surface that is swept under the enhanced sweeping program (acres) ●PLER IC-land use: Phosphorus Load Export Rate for impervious cover and specified land use (lb./acre/yr.)(Table 2-1). ●NLER IC-land use: Nitrogen Load Export Rate for impervious cover and specified land use (lb./acre/yr.) (Table 2-2). ●PRF sweeping: Phosphorus Reduction Factor for sweeping based on sweeper type and frequency (Table 2-4). ●NRF sweeping:Nitrogen Reduction Factor for sweeping based on sweeper type and frequency (Table 2-4). ●AF = Annual Frequency of sweeping. For example, if sweeping does not occur in Dec/Jan/Feb, the AF would be 9 months /12 months = 0.75. For year-round sweeping, AF=1.01 ●Efficiency:Ability to decrease the nutrient load export rate A.Factors Influencing Credit Type of Technology Used ●Mechanical broom sweepers: An older technology, less costly, generally less effective with regard to dirt removal. ●Vacuum assisted sweepers: Brooms place refuse in the path of a vacuum intake, which transports the dirt to a hopper. Overall efficiency is generally higher than that of mechanical broom sweepers, especially for smaller particles. ●High-efficiency regenerative air-vacuum: The highest efficiency sweeper and the most costly. Frequency of Sweeping ●Twice annually, in spring and fall ●Monthly: PRF and NFR is reduced by the ratio of # months swept / 12 ●Weekly 30 Impact of Technology & Frequency on Efficiency B. Example Credit Calculations The following is an example of an application to NH’s Enhanced Street/Pavement Cleaning Program for a phosphorus load reduction credit (Credit P sweeping):The permittee proposes an enhanced street/pavement cleaning program, including monthly cleanings from March 1 to December 1 (9 months), using a high efficiency, regenerative air-vacuum assisted sweeper on 20.3 acres of parking lot and roadway in a high-density residential (HDR) area of the Lake Phosphorus Control Plan (LPCP) area. For this site, the information needed to calculate the phosphorus load reduction is: ●IA swept = 20.3 acres ●PLER IC-HDR = 2.32 lb./acre/yr. (from Table 2-1) ●PRF sweeping = 0.08 (from Table 2-4 above) ●AF = (9 months / 12 months) = 0.75 Applying these values to equation 2-1 yields a credit of 2.8 pounds of phosphorus removed per year. IA swept 20.3 acres * PLER IC-HDR 2.32 lbs./acre/yr * PRF sweeping 0.08 * AF 0.75 = Phosphorus Credit P sweeping 2.8 lbs./yr. In the same LPCP area, the following information is needed to calculate nitrogen load reduction credit: ●IA swept = 20.3 acres ●NLER IC-HDR = 14.1 lb./acre/yr. (from Table 2-2) 31 ●NRF sweeping =0.08 (from Table 2-4) ●AF (9 months / 12 months): 0.75 Applying these values to equation 2-2 yields a credit of 17.2 pounds of nitrogen removed per year. IA swept 20.3 acres x NLER IC-HDR 14.1 lb./acre/yr. x NRF sweeping .08 x AF 0.75 = Nitrogen Credit N sweeping 17.2 lbs./yr. C. Questions for the Clean Sweep Expert Panel to Consider Clean Sweep will engage an Expert Panel to 1) consider whether the NH program (as outlined above) adequately reflects the science on nutrient load reductions associated with street sweeping and 2) make recommendations to update the crediting system based on what they determine. It is important for panelists to understand, for example, the type of data municipalities can realistically collect or whether there is flexibility to adapt the crediting process to consider other factors beyond land use, frequency, and technology type. We hope the panel will consider questions like the following: ●What is flexible with respect to the credit calculation process? E.g.: Could additional or different technologies or frequencies be added? Are there factors used in other states that could be considered? Are sweeping activities, and the current credits associated with them, realistic in winter months in the Northeast? ●Are there areas of the NH Enhanced Street/Pavement Cleaning Program that require clarification and/or would benefit from closer examination from a scientific perspective? E.g.: Should deposition areas be solely related to roadways or parking lots or should they expand to adjacent land use areas? What role should curb lines or sweeping medians play in assigning credit? Should we assume loading rates are consistent and uniform across seasons? ●What units make the most sense to collect from a municipal perspective? E.g.Do municipalities measure sweeping in acres? Are there policies (e.g., parking restrictions to facilitate sweeping) that could be considered in the credit calculation process? 2. Organic Matter and Leaf Litter Collection Program Summary 32 Under New Hampshire’s Enhanced Organic Matter and Leaf Litter Collection Program, permittees may earn phosphorus and nitrogen reduction credits by performing regular gathering, removal and proper disposal of landscaping wastes, organic debris, and leaf litter from impervious surfaces within applicable watershed areas (i.e., Lake Phosphorus Control Plan area or Great Bay watershed). The permittee may use an enhanced sweeping program (e.g., weekly frequency) as part of earning this credit provided the sweeping is effective at removing leaf litter and organic materials. Credit is calculated with the following equations: ●Equation 2-6: Credit P leaf litter (lbs/year) = (IA leaf litter(acres)) x (PLER IC-land use(lb/ac/year)) x (0.05) ●Equation 2-7: Credit N leaf litter (lbs/year) = (IA leaf litter(acres)) x (NLER IC-land use(lb/ac/year)) x (0.05) Definitions ●Credit leaf litter: Amount of nutrient load reduction credit for organic waste and leaf litter collection program (lb. /year) ●IA leaf litter: Impervious area (acre) in applicable watersheds that are subject to enhanced organic waste and leaf litter collection program ●PLER IC-land use: Phosphorus Load Export Rate for impervious cover and specified land use (lbs./acre/yr.) (see Table 2-1) ●NLER IC-land use: Phosphorus Load Export Rate for impervious cover and specified land use (lbs./acre/yr.) (see Table 2-1) 0.05 = 5% nutrient reduction factor for organic waste and leaf litter collection program in the applicable watershed A.Factors Influencing Credit ●Frequency & timing:To receive credit, permittees must gather and remove all landscaping wastes, organic debris, and leaf litter from impervious roadways and parking lots at least once a week between September 1 and December 1 each year. o To receive credit, permittees must remove landscaping wastes, organic debris, and leaf litter immediately following any landscaping activities in the applicable watershed and at additional times necessary to ensure removal of all aforementioned materials at least once a week. ●Disposal:To receive credit, permittees must ensure that disposal of these materials will not contribute pollutants to any surface water discharges. 33 B.Example Credit Calculations The permittee proposes an enhanced sweeping program to address leaf litter collection for 12.5 acres of impervious roadways and parking lots in an industrial/commercial part of an LPCP area. They intend to sweep the parking lots and access drives at a minimum of once a week, using a mechanical broom sweeper for the period of September 1 to December 1. They will ensure that organic materials are removed from impervious areas immediately following all landscaping activities in the area. For this site, the needed information to calculate the Credit leaf litter for phosphorus is: ●IA leaf litter = 12.5 acres ●PLER IC-commercial = 1.78 lbs./acre/yr. (from Table 2-1) Applying these values to equation 2-6 yields: Credit P leaf litter = (12.5 acre) x (1.78 lbs./acre/yr.) x (0.05) = 1.1 lbs. P/yr. For the same site, the following information is needed to calculate credit for nitrogen: IA leaf litter = 12.5 acres NLER IC-commercial = 15.0 lbs/acre/yr (from Table 2-2) Applying these values to equation 2-7 yields: Credit N leaf litter =(12.5 acre) x (15.0 lbs./acre/yr.) x (0.05) = 9.4 lbs. N/yr. C.Associated Street/Pavement Cleaning Credit The permittee also may earn an additional phosphorus reduction credit for enhanced cleaning of roads and parking lot areas (i.e., Credit P sweeping) for using a mechanical broom sweeper weekly during a three-month leaf litter collection program. Using equation 2-1, Credit P sweeping is: Credit P sweeping = IA swept x PLER IC-land use x PRF sweeping x AF (Equation 2-1) ●IA swept = 12.5 acre ●PLE IC-commercial = 1.78 lbs./acre/yr. (from Table 2-1) ●PRF sweeping = 0.05 (from Table 2-4) AF = 3 mo./12 mo. = 0.25 Applying these values to equation 2-1 yields a Credit P sweeping of 0.3 pounds of phosphorus removed per year. 34 Credit P sweeping = IA swept x PLER IC-commercial x PRF sweeping x AF = 12.5 acre x 1.78 lbs./acre/yr. x 0.05 x 0.25 = 0.3 lbs. P/yr. III. Tables 2-1, 2-2, & Consolidated 35 36 Consolidated Table 37 Appendix I: Example Credit Calculations Example 1: Measured Organic Matter Collection Credit Treesville—a beautiful, but fictional New Hampshire town—wanted to receive more credit for its leaf collection activities. Last year, they tracked the mass of material collected by their mechanical broom sweeper. They swept twice, the “minimum” effort, and collected 5,708 lbs of material in the spring and 5,840 lbs in the fall. To calculate Treesville’s credit using the measured organic matter collection approach, the following measurements were needed: ●Wet mass of material collected ●Month in which organic matter was collected The following information was also required to calculate the credits: ●Average percent moisture content (Table 1) ●TN concentration from mass (Table 1) ●TP concentration from mass (Table 1) Table 1 Season Average Percent Moisture TP Concentration from Mass (mg per kg) TN Concentration from Mass (mg per kg) Fall (Sept - Dec)0.48 857 2,762 Non-fall (Jan - Aug) 0.22 414 994 Seasonal TN and TP load reductions are derived from wet mass collected using the factors represented in Table 1. Alternatively, users can calculate their own percent moisture values developed from sub sample analysis from field collections where: Percent Moisture (%)= 𝐿𝑎𝑘𝑘 𝑘𝑎 𝑊𝑎𝑘𝑎𝑘 𝑖𝑘 𝑅𝑘𝑎𝑘𝑎𝑘𝑘𝑘𝑎 𝑅𝑘𝑘𝑎𝑘 𝑘𝑎𝑘𝑘 𝑘𝑎 𝑘𝑎𝑘𝑎𝑘 𝑎𝑘𝑎 𝑘𝑘𝑘𝑖𝑎𝑘 𝑖𝑘 𝑘𝑘𝑎𝑘𝑎𝑘𝑘𝑘𝑎*100 Credit Calculation Steps Step 1)Calculate the dry mass of material collected in the fall and “non-fall” using Equation 2 and values from Table 1: 38 Equation 2:𝑎𝑘𝑦 𝑘𝑎𝑘𝑘=𝑘𝑎𝑘 𝑘𝑎𝑘𝑘∗(1 −𝑘𝑎𝑘𝑎𝑎𝑘𝑘 𝑘𝑘𝑖𝑘𝑘𝑘𝑘𝑎 𝑎𝑘 𝑎 𝑎𝑎𝑎𝑖𝑘𝑎𝑘) Non fall collected dry mass =5708𝑘𝑎∗(1 −0.22)=4500𝑘𝑎 Fall Collected dry mass =5840 ∗(1 −0.48)=3000𝑘𝑎 Step 2)Calculate the TN and TP credit using Equation 1 and values from Table 1: Equation 1: (kg/mg)𝑅𝐿 𝑘𝑘 𝑅𝑃 𝑎𝑘𝑎𝑎𝑖𝑘= 𝑎𝑘𝑦 𝑘𝑎𝑘𝑘 (𝑘𝑎𝑘) ∗𝑅𝐿 𝑘𝑘 𝑅𝑃 𝑎𝑘𝑘𝑎𝑎𝑘𝑘𝑘𝑎𝑘𝑖𝑘𝑘 (𝑘𝑎/𝑘𝑎) ∗10−6 Non fall TP credit == 1.8 lbs4500∗141 ∗10−6 To prevent mixing up fall and non fall credit, it is helpful to make a table (Figure 1). Figure 1: Seasonal Measured Credit Calculations in Different Seasons Wet mass (lbs) Time of year collected Seasonal avg. dry moisture content (%) Calc. dry mass (lbs) TN Con (mg/kg) TP Conc. (mg/kg) TN Calc. Credit TP Calc. Credit Municipalit y Municipality Table 1 Equat. 2 Table 1 Table 1 Equat. 1 Equat. 1 5708 Not Fall 0.22 4500 994 413.6 4.4 1.8 5840 Fall 0.48 3000 2762 857 8.4 2.6 Total 12.8 4.4 After calculating TN and TP credits for material collected during the fall and the non fall, Treesville would receive credit for 12.8 lbs of TN and 4.4 lbs of TP removed for the year. Note that the credit for TN using this approach is roughly 10 times more than Treesville would have received had they applied the model-based approach with a minimum level of effort. If the town chose to sweep more frequently, particularly in the fall, they could have received more credit. Example 2: Model-based Street Cleaning Credit Treesville sweeps their streets twice a year with a mechanical broom sweeper—once in the fall and once in the spring. The sweeper travels 9.5 miles on its route. Since they do not track mass collected, and they only sweep twice a year, they can only pursue the “low effort,” model-based street cleaning credit. To calculate the modeled credit, they need the following information: 39 ●Acreage swept by sweeper: Assuming the sweeper clears an 8ft wide path on its 22 mile route it covers 9.2 acres 9.5𝑘𝑖 ∗ 5280𝑎𝑘 𝑘𝑖∗8𝑎𝑘 ∗ 1𝑎𝑎 43560𝑘𝑘 𝑎𝑘 ●Type of sweeper: mechanical broom, therefore the sweeper PRF/NRF is 0.01 (Table 3) ●TP land export rate: 1.96 lb/ac/yr (Table 3) ●TN land export rate: 14.1 lb/ac/yr (from Table 3) Table 3: Updated Parameters for New Hampshire’s Model-based Credit for Street Cleaning Parameter Minimum Effort Medium effort Maximum Effort Frequency Up to twice per year in any season. NRF/PRF = 0.01 for mechanical sweeper and 0.02 for vacuum. Every other week in the fall (September to December). NRF/PRF = 0.15 Monthly routine maintenance with more intensive (weekly) in Fall (September. to December.) and early spring. NRF/PRF = 0.25 with enhanced leaf collection.Assumes a vacuum sweeper (defined above), but may be combined with other efforts. Location & seasonality To accommodate seasonal increases in TN and TP and simplify the location parameter: 3)Use the medium density residential IC land use, which integrates the most conservative TP and TN loading rates of all land uses in the current model. 4)For intensive weekly sweeping during the fall in times of high organic material deposition, offer a 10% additional removal factor. This is a 5% increase over the existing enhanced leaf collection credit in the current model and better reflects removals in recent literature. (This is synonymous with maximum effort.) Credit Calculation Steps Step 1)Calculate area swept: 𝐴𝑘𝑎𝑎 𝑘𝑘𝑎𝑘𝑘 (𝑎𝑎𝑘𝑎𝑘) = 𝑘𝑎𝑘𝑎 𝑘𝑖𝑘𝑎𝑘 𝑘𝑘𝑎𝑘𝑘 *5280 𝑎𝑘 𝑘𝑖 ∗1 𝑎𝑎𝑘𝑎 43560 𝑘𝑘 𝑎𝑘 Step 2)Calculate TP credit using Equation 3: Equation 3: Credit TP =area swept * TP load export rate * TP reduction factor (PRF) of sweeper type. TP credit =9.2𝑎𝑎 ∗ 0.01 ∗ 1.96𝑘𝑎𝑘 𝑎𝑎·𝑦𝑘=0.18𝑘𝑎𝑘 𝑦𝑘 40 Step 2)Calculate annual TN credit using Equation 4: Equation 4: Credit TN = area swept * TN load export rate * TN reduction factor (PRF) of sweeper type. TN credit =9. 2𝑎𝑎 ∗ 0. 01 ∗ 41.1𝑘𝑎𝑘 𝑎𝑎·𝑦𝑘=1.3𝑘𝑎𝑘 𝑦𝑘 Example 3: Comparison of Different Levels of Effort for Model-based Street Cleaning Credits Figure 2 compares credit received by applying the model-based street cleaning approach in three towns using different levels of effort. Figure 2: Model Credit Calculations for Towns Using Different Levels of Effort Modeled Inputs (from Permittee) Credit Calculation lane miles times swept area swept (ac) TN export rate lb/ac/yr TP export rate lb/ac/yr PRF/NRF TN CREDIT lbs/yr TP CREDIT lbs/yr Table 3 Table 3 Table 3 Equation 4 Equation 3 Minimum Effort Town 9.5 twice 9.21 14.1 1.96 0.01 1.3 0.18 Medium Effort Town 9.5 6 times in fall 9.21 14.1 1.96 0.15 19 2.7 Maximum Effort Town 9.5 more than monthly 9.21 14.1 1.96 0.25 32 4.5 41 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY Region 1 5 Post Office Square BOSTON, MA 02109-3912 August 15, 2022 James Houle, Director University of New Hampshire Stormwater Center West Edge Lot, NW Corner Durham, NH 03824 james.houle@unh.edu RE: EPA Support on 2021-2022 Clean Sweep Panel Process Results for Adaptive Management Plans for the Great Bay Total Nitrogen General Permit EPA Region 1 (R1) commends the University of New Hampshire Stormwater Center and Piscataqua Region Estuaries Partnership for a successful Clean Sweep Panel process for developing enhanced and updated street sweeping credits for municipalities. The panel process has again demonstrated an excellent model for leveraging both regional and national subject matter experts on a specific topic for developing new approaches for stormwater management backed by the latest research. The Clean Sweep Panel developed two alternative options for obtaining pollution reduction credits for street cleaning. Through the first option, permittees could receive credit by measuring the amount of organic matter collected throughout the year—an approach pioneered in Minnesota (Minnesota Pollution Control Agency 2022). The second option would allow permittees to use an updated version of the model that specifies New Hampshire’s current Enhanced Street/Pavement Cleaning Program credits. This would offer credit for municipal sweeping efforts depending on the technology used, frequency of cleaning, seasonality, and location. The Great Bay Total Nitrogen General Permit in New Hampshire represents adaptive implementation opportunities for broadening the use of non-structural nitrogen control credits. EPA looks forward to implementation of the two alternative options developed by the panel for obtaining credit for street cleaning under the adaptive management plans adopted by Great Bay permitted municipalities. The Great Bay municipalities with adaptive management plans could use either option to receive credit, but not both, within a single reporting year. EPA R1, through this communication, supports the use of these alternative methods. The piloting of these methods will provide insight and adaptive improvement of the new credits and offer opportunities to validate the approaches for future use throughout New England. Information gained during the piloting of the new credits could allow EPA R1 to integrate these 42 credits, or an iteration of these credits, into the next New Hampshire and Massachusetts Small MS4 General Permits. Overall, enhanced street sweeping credits will hopefully incentivize municipalities to modernize street sweeping programs throughout the Great Bay watershed and help make progress towards pollution reductions in Great Bay. We look forward to continued collaboration and analysis of the pilot’s results. Sincerely, Melville P. Coté, Jr., Chief Surface Water Protection Branch Water Division cc: Abigail Lyon, Region Estuaries Partnership—Via Email Sally Soule, New Hampshire Department of Environmental Services—Via Email 43 Appendix K: Ground Truthing Minnesota Data for New Hampshire, an Addendum to the Clean Sweep Technical Memo April 21, 2023 Contents 1.Summary 2.Pilot results: Option 1: Organic Matter Collection Credit (Measured Approach) 3.Pilot results: Option 2: Updated Street Cleaning Credit (Model-Based Approach) 4.Sweeping and Structural BMP Cost Comparison 1. Summary In Clean Sweep: Recommendations for New and Updated Credits for Street Cleaning in New Hampshire,an expert panel recommended updating the state’s model-based street/pavement cleaning credit and creating a new, “measured” option that offers credit for the amount of organic matter collected. This addendum summarizes a pilot study conducted by the University of New Hampshire (UNH) Stormwater Center to provide local data to ground truth the utility of the panel’s recommendations. Overall, the pilot’s results supported the adoption of Minnesota’s street sweeping nutrient and moisture content values in New Hampshire and provided promising preliminary results for a volume-based credit. This effort was made possible with support from the Piscataqua Region Estuaries Partnership, the Town of Durham, the City of Dover, and UNH’s Facilities Division. 2. Option 1: Organic Matter Collection Credit (Measured Approach) To receive the proposed credit, communities first track the mass of sweepings and time of year they are collected. Then, to determine pounds of Total Phosphorus (TP) and Total Nitrogen (TN) removed, they use a series of conversion factors based on moisture and nutrient content typical for organic matter in that season. These conversion factors are based on the street sweeping credit recently adopted by Minnesota. That credit is based on a rigorous study in the Minneapolis/St. Paul Metropolitan Area, conducted by the University of Minnesota and the Minnesota Pollution Control Agency. The Minnesota credit (and the ones proposed for New Hampshire) rely on three conversion factors from the Minnesota study: average moisture content, and TP and TN concentrations. Each of these have two values depending on whether the material was collected in the fall or during the rest of the year (Table 1). 44 Table 1: MInnesota-based Conversion Factors Season Average Moisture Content TP Concentration from Mass (mg/kg) TN Concentration from Mass (mg/kg) Fall (Sept to Dec) 0.48 857 2,762 Non-fall (Jan to Aug) 0.22 414 994 Since these conversion factors are based on research conducted in Minnesota, the Clean Sweep expert panel recommended a study to assess whether moisture content and TP and TN concentrations in New Hampshire are comparable. In response, the UNH Stormwater Center ground truthed the Minnesota conversion factors using local data. As a secondary aim, they tried to establish average bulk density by looking at the relationship between measured mass and measured volume. This analysis was based on subsamples from 27 sweeper loads provided by the City of Dover, which did ten intensive days of sweeping in the fall of 2022 (Table 2). Table 2: Sample Collection in Partnership with Dover Days Sweeper Man Hours Estimated Cubic Yards Collected Measured Wet Weight Collected (lbs) Subsamples Analyzed 10 144 228 83,520 27 Samples were analyzed for TP, TN, and moisture content. The results, and the corresponding values from the Minnesota study, are shown in Table 3, with first quartile results for the TP and TN concentrations. (Minnesota’s credit uses the first quartile of the TP dataset, which their study found to be conservative, a conclusion supported by the Clean Sweep expert panel.) Table 3: Analysis of New Hampshire Samples Average Percent Moisture Content TP concentration from mass (mg/kg) TN concentration from mass (mg/kg) MN data (fall)48%857*2,762* Dover data (fall)42%1,003*2,900* * first quartile The moisture content and TP and TN concentrations of the New Hampshire samples were similar to Minnesota values. While the study only looked at fall sweepings, its results do not raise concerns that New Hampshire values would differ greatly from those in Minnesota. For further confirmation, a similar study could be repeated in the spring or summer. 45 To support the secondary aim of the study, the UNH Stormwater Center team also analyzed sweeper subsamples for wet and dry bulk density. (The volume of material in the hopper was estimated before weighing.) Using hopper volume and wet bulk density, the research team calculated hopper mass and plotted that against the measured hopper mass. (See Figure 1.) Figure 1: Calculating the Wet Mass The relationship between calculated and measured wet mass is not perfect, but reasonable, given the variability of environmental data. While the measured credit currently could be applied now using mass, additional research to explore the relationship between mass and volume may allow the credit to be calculated from sweeping volume. Given that many communities are not able to measure mass of sweepings easily, an option based on volume would greatly expand the usability of the new credit. While not the focus of this study, the Measured Approach gives substantially more credit than the current sweeping credit and better reflects the latest research on the effectiveness of organic matter cleanup (Table 4). 46 Option 2: Updated Street Cleaning Credit (Model-Based Approach) New Hampshire’s current street sweeping regulations require communities to track multiple parameters, are inflexible around sweeping timing, and provide relatively little credit. That credit is determined by a model that requires inputs of sweeper type, land use, area swept, and annual frequency of sweeping. Tracking miles swept in each land use area is not always simple given that one route may pass through different land uses. Further, the annual frequency of sweeping is based on the number of months of sweeping, which makes it difficult to determine credit for intensive or intermittent sweeping. To qualify for additional credit for enhanced organic matter collection, communities must sweep at least weekly from September to December, even after leaf and organic matter collection activities are complete. The revised credit proposed by the Clean Sweep expert panel simplifies the current model and only requires tracking of lane miles and frequency. Other parameters are determined by fitting a sweeping program into three categories of effort: minimal, medium, and maximum (Table 5). Table 5: Updated Parameters for New Hampshire’s Model-based Credit for Street Sweeping Parameter Minimum Effort Medium Effort Maximum Effort Frequency Up to 2 times per year in any season. NRF/PRF* = 0.01 for a mechanical sweeper and 0.02 for a vacuum. Every other week in the fall (Sept. to Dec.). NRF/PRF = 0.15 Monthly routine maintenance with more intensive (weekly) in Fall (Sept. to Dec.) and early spring. NRF/PRF = 0.25 with enhanced leaf collection. Assumes a vacuum sweeper (defined above), but may be combined with other efforts. Location and seasonality To accommodate seasonal increases in TN and TP and simplify the location parameter: 1) Use medium density residential impervious cover land use, which integrates the majority of likely land uses. 2) For intensive (weekly) fall sweeping in times of high organic material deposition (leaf fall), offer a 10% additional removal factor. This is a 5% increase over the enhanced leaf collection credit in the current model and better reflects removals in the recent literature. (Synonymous with maximum effort.) The UNH Stormwater analysis was primarily concerned with ground truthing the proposed measured credit, but also tracked lane miles swept. This made it possible to calculate the annual sweeping credit with both the current and proposed model (Table 6). Since Dover did not track land use along all sweeper routes, it was necessary to assume a medium density residential land use. Also, since their intensive sweeping was in the fall, the annual frequency is two out of 12 months of the year. 47 The updated model gives substantially more credit for the same effort and better reflects the latest research on the effectiveness of organic matter cleanup. It is also a better fit for the metrics tracked by municipalities and the current sweeping practices. Table 6: 2022 Dover Sweeping Example Lane Miles Impervious area (acres) Annual Frequency PRF*PLER * (lb/ac/yr) NRF*NLER * (lb/ac/yr) TP credit (lb/yr) TN credit (lb/yr) Old Model 13.68 13.27 0.17 0.01 1.96 0.01 14.1 0.04 0.31 New Model 13.68 13.27 NA 0.15 1.96 0.15 14.1 3.9 28.06 *NLER IC-land use:Nitrogen (TN) Load Export Rate for impervious cover and specified land use (lb/acre/yr) PLER IC-land use:Phosphorus (TP) Load Export Rate for impervious cover and specified land use (lb/acre/yr). NRF sweeping:Nitrogen (TN) Reduction Factor for sweeping based on sweeper type and frequency. PRF sweeping:Phosphorus (TP) Reduction Factor for sweeping based on sweeper type and frequency 4. Sweeping and Structural BMP Cost Comparison The UNH Stormwater Center team compared City of Dover cost figures, recorded during the pilot sweeping study, to cost estimates for structural stormwater control measures built into the UNH BMP Performance Calculator (Table 7). For this comparison, structural BMPs were sized to treat a one-inch storm, and costs of both sweeping and structural BMPs were normalized to one acre of impervious area. There are many factors that affect costs, and this estimate does not take into account the costs of sweeping equipment or ongoing maintenance on structural BMPs. However, it does indicate that sweeping can be a cost effective option for reducing TN and TP pollution in watersheds. 48 49 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 F.2: Credit Calculations CLIENT:Town of Lexington, Massachusetts PROJECT:Phosphorus Control Plan DESIGNED BY:LFE DATE:5/26/2023 CHECKED BY:DATE: PROJECT NO.227871.12 40 Shattuck Road, Suite 110 Andover, MA 01810 Tel: 978.557.8150 Fax: 978.557.7948 Material Mass (lbs) per Volume (CY) - Street Sweepings (Fall)1,850 Collected Volume of Street Sweepings (CY)60 Total Collected Wet Mass of Street Sweepings (lb)111,000 Dry Mass (lb) = 57,720 TP Removed (lb) =49.47 Net Reduction (lbs/year)49.47 Phosphorus Load Reduction (lbs/year) Enhanced Sweeping 1.96 98.5 1.93 Net Reduction (lbs/year)1.93 NOTES: 1. Clean Sweep Memorandum for enhanced sweeping credit: 2x/year sweeping using a mechanical broom sweeper. Entire paved area (driveways, parking lots, sidewalks, patios, etc.) is swept. Use Medium-Density Residential Land Use Export Rate. Town-Owned Non-Structural Phosphorus Reduction Analysis - Clean Sweep Policy Measured Organic Matter Collection Credit Model-Based Street Cleaning Credit MassGIS Land Use (2016)Export Rate (lbs/ac/year) Roadway Area (ac) Medium-Density Residential CLIENT:Town of Lexington, Massachusetts PROJECT:Phosphorus Control Plan DESIGNED BY:LFE DATE:5/26/2023 CHECKED BY:DATE: PROJECT NO.227871.12 40 Shattuck Road, Suite 110 Andover, MA 01810 Tel: 978.557.8150 Fax: 978.557.7948 1.78 2.6 0.05 1.95 78.4 1.53 2.32 6.8 0.16 1.96 66.9 1.31 1.52 - 0.00 1.34 - 0.00 1.52 - 0.00 1.52 5.3 0.08 1.52 -0.00 Net Reduction (lbs/year)3.12 NOTES: 1. Catch basin impervious drainage area was estimated using the Metropolitan Area Planning Council (MAPC) Catchment Delineation Tool 2. Catch basin cleaning credit for annual cleaning frequency (assumes 1%) Open Land Agriculture Right-of-Way Commercial and Industrial Multi-Family and High-Density Residential Medium-Density Residential Low-Density Residential Highway Forest Town-Owned Non-Structural Phosphorus Reduction Analysis - Charles River Watershed Town-Owned Roadway Catch Basin Cleaning MassGIS Land Use (2016) Export Rate (lbs/ac/year) Impervious Acreage Catch Basin Cleaning Total Reduction (lbs/year) Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX G: PLANNED STRUCTURAL CONTROLS G.1: Municipal Parcel Evaluation G.2: Feasibility Assessment G.3: Concept Figures Figure G-1: Jonas Clarke Middle School Figure G-2: Bowman Elementary School Figure G-3: Regional Retrofit 1 – Munroe Road Figure G-4: Regional Retrofit 2 – Philip Road Figure G-5: Regional Retrofit 3 – Green Lane Figure G-6: Regional Retrofit 4 – Valleyfield Street 1 Figure G-7: Regional Retrofit 5 – Valleyfield Street 2 Figure G-8: Roadway Retrofit – Ewell Avenue Figure G-9: Roadway Retrofit – Benjamin Road Figure G-10: Roadway Retrofit – Valleyfield Street Figure G-11: Roadway Retrofit – Crosby Road Figure G-12: Roadway Retrofit – Clematis Road Figure G-13: Roadway Retrofit – Elena Road Figure G-14: Roadway Retrofit – Piper Road Figure G-15: Roadway Retrofit – Allen Street Figure G-16: Infiltration Trench Design Figure G-17: 2021 Road Surface Ratings Map G.4: BATT Credit Calculations Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 G.1: Municipal Parcel Evaluation 31-54B 10-26A 17-5B 42-199 51-45A 51-14B 44-3A 34-164 34-124A 31-90C 31-63D 32-60 34-181 32-12 32-177C 34-189 31-54B 31-54B 31-54B 31-54B 24-60 24-134 24-52 24-24 24-75 24-121 15-45B 15-45B 19-2 16-36B 9-108 16-62A 11-96A 10-48 9-92 9-143 8-45 6-1 4-1A5-39 5-18A 4-12 Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan,METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS User Community LegendMunicipal Properties(Western Watershed) Charles River WatershedPhosphorous Control Program Figure Exported: 4/13/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\Municipal Parcels.mxdProject #: 0227871.08Map Created: May 202100.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Lexington Boundary Parcel Municipally Owned Parcels Charles River Basin 7 20 15 18 14 4 5 22 1 11 6 Municipal Parcel with Retrofit Potential Rank1 Municipal Roadway Parcel 1 6 3 4 1 Municipal Roadway Parcel with Retrofit Potential Rank 31-54B 10-26A 8-18B 17-5B 42-199 51-45A 51-14B 34-164 34-124A 31-90C 31-63D 31-63E 32-60 34-181 32-12 32-177C 34-189 31-54B 31-54B 31-54B 31-54B 24-60 24-134 24-52 24-24 24-75 14-111E 24-121 15-45B 15-45B 15-19 13-107 16-36B 9-108 16-62A 8-67 11-96A 10-48 9-92 9-143 8-45 8-47 6-1 4-1A5-39 5-18A 4-12 1-1B Sources: Esri, HERE, Garmin, Intermap, increment P Corp., GEBCO, USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey, Esri Japan,METI, Esri China (Hong Kong), (c) OpenStreetMap contributors, and the GIS User Community LegendMunicipal Properties(Eastern Watershed) Charles River WatershedPhosphorous Control Program Figure Exported: 4/13/2022 By: esneesby Using: \\woodardcurran.net\shared\Projects\0227871.10 Lexington MA - FY22 MS4 SW Comp Charles Riv\wip\GIS\Project Files\Municipal Parcels.mxdProject #: 0227871.08Map Created: May 202100.25 0.50.125 MilesLexington, MA Third Party GIS Disclaimer: This map is for reference and graphical purposes only and should not be relied upon by third parties for any legal decisions. Any reliance upon the map or data contained herein shall be at the users’ sole risk. Data Sources: Lexington Boundary Parcel Municipally Owned Parcels Charles River Basin 2 17 3 21 8 19 10 9 13 23 16 12 1 Municipal Parcel with Retrofit Potential Rank 7 5 2 8 Municipal Roadway Parcel 1 Municipal Roadway Parcel with Retrofit Potential Rank Rank Parcel ID Address/Location Parcel Conservation/ Land Cover Outfall Average Sample TP Concentration (mg/L) Number of Samples Potential Stormwater Control Measure Approximate Drainage Area (acres) Evaluation Notes 1 24-121 Valleyfield Street Conservation/wooded OF107 NR 6 Infiltration Basin/Chambers 48 5.5 20.6 Very steep slopes at end of pipe. Could look to acquire a drainage easement at end of Munroe Road or subsurface infiltration chambers (HSG A soils) 2 31-54B 130R Marrett Road Conservation/wooded OF75 & OF76 NR 4 Infiltration Basin 27 3.1 13.0 Constructed on Moreland Ave property, HSG A 3 8-47 Pleasant Street Wooded OF320 - 0 Infiltration Basin 33 3.8 11.0 Design offline BMP from DMH764, difficult access near residential homes 4 32-12 Valleyfield/Waltham Street Sparsely wooded N/A - - Infiltration Basin 29 3.2 9.4 Design offline BMP from DMH317, large drainage area for small parcel, not rated HSG but surrounded by A 5 24-52 Valleyfield Street Conservation/brush OF308 NR 1 Constructed Wetlands 100 6.9 9.3 Design offline BMP from DMH332, very tight with existing wetlands - might not be feasible, large drainage area for small parcel 6 24-121 Valleyfield Street Conservation/wooded OF104 0.1 2 Infiltration Basin 17 1.9 8.2 A/D soils 7 34-124A Middle Street Conservation (community gardens)/wooded OF123 NR 2 Constructed Wetlands 18 1.3 5.5 Design offline BMP between stream and driveway with outfall from DMH1138 8 31-54B 130R Marrett Road Conservation/brush OF490 NR 8 Constructed Wetlands 22 1.5 5.1 Steep grade, close to existing wetlands and stream, retrofit outfall to outlet upgradient of wetlands 9 31-54B 130R Marrett Road Conservation/wooded OF33 - 0 Constructed Wetlands 16 1.1 4.9 Difficult wooded access, close to existing wetlands 10 31-54B 130R Marrett Road Conservation/wooded OF40 NR 2 Constructed Wetlands 25 1.7 4.0 Steep grade, close to existing wetlands, potential sewer conflict 11 24-121 Valleyfield Street Conservation/wooded OF21 NR 1 Constructed Wetlands 12 0.9 3.7 A/D soils, near wetlands so may have high groundwater, difficult access near residential homes 12 10-26A Concord Ave State Park Conservation/brush OF453 NR 11 Constructed Wetlands 16 1.1 3.6 Close to existing wetlands 13 31-54B 130R Marrett Road Conservation/wooded OF35 NR 3 Constructed Wetlands 14 1.0 2.3 Steep grade, close to existing wetlands 14 17-5B Hayden Ave Sparsely wooded N/A - - Bioretention 4 0.6 2.3 Offline BMP from DMH965, potential gas pipeline conflict 15 34-181 Bicentennial Drive Wooded N/A - - Bioretention/Constructed Wetlands 8 0.5 2.2 Design BMP offline with outfall from DMH1143, close to stream 16 5-39 Scott Road Conservation/wooded Unnamed - - Constructed Wetlands 8 0.5 1.8 Very steep slopes at end of pipe, might not be feasible, A soils but near wetlands so may have high groundwater 17 8-45 Pleasant Street Grass N/A - - Infiltration Basin 5 0.5 1.5 Potential gas pipeline conflict, close to residential home, large drainage area for small parcel 18 6-1 Concord Ave Conservation/wooded OF526 NR 1 Infiltration Basin 2 0.4 1.5 Might be treated by an existing BMP - difficult to tell 19 31-54B 130R Marrett Road Conservation/wooded OF451 NR 2 Constructed Wetlands 8 0.6 1.3 Steep grade, close to existing wetlands, potential overhead wire conflict 20 34-164 Idylwilde Road Conservation OF312 NR 5 Bioretention 5 0.3 1.3 Close to residential homes, portion of catchment is outside watershed 21 9-143 Blossom Park Conservation OF506 NR 1 IA Disconnection - Remove Curb 3 0.9 1.3 Runoff is treated by vegetation 22 24-60 Bridge Street Wooded N/A - - Constructed Wetlands 5 0.3 1.1 Design offline BMP from DMH319, possible stream/wetland conflict 23 13-107 Sutherland Park Woods Conservation/wooded OF65 NR 1 Constructed Wetlands 6 0.4 1.0 Close to existing wetlands, difficult access near residential homes Rounded Sum 38.0 116.0 Notes: 1. Estimated load reduction based on composite PLER for drainage area (MS4 Appendix F, Attachment 1, Table 1-1). Load is not based on actual impervious and pervious cover in drainage area. 2. Estimated load reduction based on approximated feasible treated runoff depth considering drainage area and available space on parcel. Sizing calculations are necessary to verify system performance. 3. Retrofit analysis does not consider drainage system invert elevations, headloss, seasonal high groundwater, or other constraints that may affect the feasibility of these systems. 4. NR = no results for phosphorus concentration from sample Estimated Load Reduction Range (lbs TP/year) Municipal Parcels with Retrofit Potential Parcel ID Address/Location Outfall Average Sample TP Concentration (mg/L) Number of Samples Potential Stormwater Control Measure Evaluation Notes 44-3A Marrett Rd/Minute Man Voc Tech N/A --N/A No impervious drainage area or mapped outfalls 34-124A Middle Street (Idylwilde Farms)OF313 NR 5 N/A Outfalls to wetland 19-2 Hobbs Brook Res N/A --N/A No impervious drainage area or mapped outfalls 11-96A Concord Ave OF113 -0 N/A Outfalls to wetland, limited drainage area 24-134 Grassland Street OF528 NR 1 N/A Nearly entirely wetlands, property across street has limited impervious drainage area 24-24 Valleyfield Play Area N/A --N/A High point compared to surrounding area 24-121 Valleyfield Street OF105 NR 1 N/A Minimal impervious drainage area 24-75 Brookside Ave/Waltham St OF309 NR 2 N/A Minimal impervious drainage area 14-111E Moreland Ave N/A --N/A Upstream portion of watershed, limited impervious drainage area 15-19 Rockville Ave N/A --N/A Upstream portion of watershed, limited impervious drainage area 16-36B Blossomcrest Road N/A --N/A Limited impervious drainage area 16-62A Blossomcrest Road N/A --N/A Limited impervious drainage area 9-108 Blossomcrest Road N/A --N/A Limited impervious drainage area 9-92 Hanson Ave N/A --N/A Limited impervious drainage area 8-18B Pleasant Street N/A --N/A Limited impervious drainage area 8-67 Bowman Park N/A --N/A Upstream portion of watershed, limited impervious drainage area 10-48 Behind Cotting School N/A --N/A Nearly entirely wetlands, limited impervious drainage area 4-1A Concord Ave N/A --N/A High point compared to surrounding area 4-12 Concord Ave N/A --N/A High point compared to surrounding area 1-1B Concord Ave OF455 0.04 4 N/A Direct outfall to stream 24-121 Valleyfield Street OF22 NR 2 N/A Minimal impervious drainage area 34-189 Bicentennial Drive N/A - - N/A Narrow strip of land along Bicentennial Drive, partially within wetlands 24-75 Brookside Ave/Waltham St OF310 NR 2 N/A Nearly entirely wetlands, limited area between ROW and wetlands Notes: 1. NR = no results for phosphorus concentration from sample Municipal Parcels with Limited Retrofit Potential Parcel ID Address/Location Parcel Land Use/Cover Outfall Average Sample TP Concentration (mg/L) Number of Samples Potential Stormwater Control Measure Evaluation Notes OF144 NR 2 OF145 NR 2 32-177C 17 Stedman Road Clarke Middle School OF502 -0 TBD Currently evaluating 31-65A 20 Pelham Road Lexington Children's Place OF460 NR 1 N/A Site has been redeveloped recently. Most impervious area is treated. BMPs have been credited 31-63D 39 Marrett Road Community Center N/A --N/A Site discharges to infiltration basin constructed pre-2005 15-45B 9 Philip Road Bowman Elementary School N/A --TBD Currently evaluating Notes: 1. NR = no results for phosphorus concentration from sample Municipal Parcels with Impervious Area Site has been redeveloped recently. Most impervious area is treated. BMPs have been credited51-45A 7 Crosby Road Maria Hastings Elementary School N/A 1.45 0.51 0.93 Infiltration Trench 69% 0.714Proposed infiltration trench with piping running south from existing catch basin, estimated 576 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate0.54 0.18 0.35 Infiltration Trench 93% 0.348Proposed infiltration trench with piping running south from existing catch basin, estimated 468 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate2 Benjamin Road 42 A 3.43 1.20 2.11 Infiltration Trench 44% 1.057 $93,361Proposed infiltration trench with piping running south from existing catch basin, estimated 648 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate3 ***Valleyfield Street 37 **A 5.94 1.29 4.65 Infiltration Trench 38% 1.007 $95,401Proposed infiltration trench with piping running south from existing catch basin, estimated 720 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate4 Crosby Road 25 **A 3.59 1.39 2.21 Infiltration Trench 30% 0.832 $91,321Proposed infiltration trench with piping running south from existing catch basin, estimated 576 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate5 Clematis Road 41 D 0.73 0.25 0.48 Enhanced Biofiltration (w/ ISR) 76% 0.504 $119,144Proposed enhanced biofiltration system (w/ ISR) in proposed roundabout in the cul-de-sac area, estimated 1250 CF storage volume. Please note ROM cost excludes any potential utility relocation.6 Elena Road 45 C/D 0.26 0.26 0.00 Enhanced Biofiltration (w/ ISR) 77% 0.390 $110,647Proposed bioretention basin (no underdrain) in proposed roundabout in the cul-de-sac area, with estimated 1007 CF storage volume7 Piper Road 45 **A 0.82 0.16 0.66 Infiltration Trench 89% 0.296 $87,241Proposed infiltration trench with piping running south from existing catch basin, estimated 432 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate8 Allen Street 42 D 0.09 0.04 0.05 Biofiltration 21% 0.021 $75,925 Proposed biofiltration/tree box filter system to replace existing catch basinTotal5.169 $777,622Notes and AssumptionsAll TP load calcluations assume Medium-Density Residential land cover useDrainage area defined as catchment for individual catch basin/inlet for a Stormwater Control MeasureRemoval efficiency for each SCM determined by performance curves (MS4 General Permit Appendix F Attachment 3)Ranking in order of highest TP reduction potentialCost estimate based on unit cost from 2020 "mixed" development land costs including materials, installation, and design from UNHSC Performance Curves *Repair Category Number in reference to 'Major Rehabilitation' category based on Town's Road Surface Ratings & Repair Categories from Pavement Management Program, issued February 16, 2021**Soil group requires confirmation via test pits***Valleyfield Street roadway retrofit may be replaced by Regional Retrofit Concept #4 or #5 due to overlap in catchment areaSoil GroupEwell Avenue $104,582Municipal Roadway Retrofit OpportunitiesRankTotal Catchment Area (ac)Impervious Area (ac)Pervious Area (ac)Street*Repair Category NumberProposed Stormwater Control Measure (SCM)TP Reduction (lb/yr)Removal Efficiency1 34 ANotesROM Cost Estimate ($) Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 G.2: Feasibility Assessment CLIENT:Town of Lexington, Massachusetts PROJECT:Phosphorus Control Plan DESIGNED BY:LFE DATE:5/26/2023 CHECKED BY:DATE: PROJECT NO.227871.12 40 Shattuck Road, Suite 110 Andover, MA 01810 Tel: 978.557.8150 Fax: 978.557.7948 Address/Location Estimated Credit (lbs/year) Parcel ID Ownership Considerations Recommended Next Steps Philip Road 12.3 31-54B Town of Lexington Associated with Bowman School, but across the street. Does facilities need notification? Categorize as first tier priority. Proceed with wetland delineation, test pits, and survey. Bowman Elementary School TBD 15-45B Town of Lexington Various retrofit options Categorize as first tier priority. Request record geotechnical information and record CAD files from facilities. Jonas Clarke Middle School 1.5 32-177C Town of Lexington Requires coordination with facilities to understand school master plan and schedule. Categorize as first tier priority. Request record geotechnical information from facilities, including test pits performed by Schofield Brothers in 2015 for vegetated swale project. 17-22 95 Hayden LLC C/O Hobbs Brook Management LLC 17-5D Town of Lexington 33-273 Zhuang Ziaomie & Wang Chester Trustees ROW Town of Lexington 32-12 Town of Lexington Green Lane 7.7 8-47 Town of Lexington Field investigation of inverts at DMH764 indicates that surface SCMs are not feasible. Consider subsurface proprietary treatment systems, such as Contech Jellyfish filters. Second tier priority due to higher capital and maintenance costs. Conduct land title review to confirm easement rights. Categorize as second tier priority - consider for future phases. Record plan review indicates that land easements from private landowner may be required. Conduct land title review to confirm easement rights in areas designated as "retention basins" on subdivision plans. Conduct test pits to determine if infiltration within the ROW is an option. Second tier priority due to easement acquisition and infrastructure costs - consider for future phases. Valleyfield Street Munroe Road 4.9 18.5 Proximity to streams/wetlands and steep topography limits opportunity. Would require either land easements from private landowner or clearing of conservation land (Hayden Woods). Higher capital and maintenance costs due to land right acquisition or access road investment. Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 G.3: Concept Figures 208207207208COMMITMENT & INTEGRITY DRIVE RESULTS Woodard & Curran 40 Shattuck Road, Suite 110 Andover, Massachusetts 01810 866.702.6371 | www.woodardcurran.comFIGURE G-1SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTS Woodard & Curran 40 Shattuck Road, Suite 110 Andover, Massachusetts 01810 866.702.6371 | www.woodardcurran.comFIGURE G-2SITE LOCATION 100 WL2525 50100 50 5025 WL WL WL WL 25 100 EA S E WL2525 50 50 25 25 50 25 25WL WL 25 EASE EASE 50 25WLWL 505025WL 25 50 50 25 50 25 WL 25 WL WL WL WL WL 25 25 100 100 25 25 25WLWL WL 50 50 50 WLWL 25 WL 25 50 EAS E EAS E 50 50 WL 25 25 EAS E EAS E EAS E EAS E EAS E 5025 50 50 WL100 EA S E EA S E EA S E EA S E EAS E WL EA S E EA S E EA S E100 100 25 100 100WL25EASEEASEEASEEASEEASEEASE50 25 5050EASEEASE EASE EASE 25100 WL25EASEEASEEASE25100 50 50100 50 50100 25 100 WLWL25WL WL 25 2525 25 100 50 2525 COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-3 SITE LOCATION ELEVATION VIEW2'-0"SUMPTYPPLAN VIEW(TOP SLAB NOT SHOWN FOR CLARITY)8'-0"12'-0"CONTECH TO PROVIDEGRADE RING/RISERCONTRACTOR TO GROUTTO FINISHED GRADESTEP TYP.TRANSFER OPENINGTRANSFEROPENINGDRAINDOWNCARTRIDGEDECK WEIRINLET BAYHI FLOCARTRIDGESTEPS (LOCATION MAY VARY)OUTLETBAYBYPASSWEIRFLOATABLESBAFFLEOUTLET TRANSFEROPENINGINLET TRANSFEROPENINGCARTRIDGEDECKCARTRIDGEFRAME AND COVER(TRENCH COVER/GRATE OPTION ISFLUSH WITH TOP OF STRUCTURE)INLET PIPEOUTLET PIPEBOTTOM OFFLOATABLESBAFFLETOP OF BYPASS WEIRCOMMITMENT & INTEGRITY DRIVE RESULTS Woodard & Curran 40 Shattuck Road, Suite 110 Andover, Massachusetts 01810 866.702.6371 | www.woodardcurran.comFIGURE G-4SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-5 SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-6 SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-7 SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-8 SITE LOCATION © 2022 Microsoft Corporation © 2022 Maxar ©CNES (2022) Distribution Airbus DS C- 0 2 D R AW I NG NU M B E R COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-12 SITE LOCATION FIGURE G-9 COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-10 SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-14 SITE LOCATION FIGURE G-11 COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-11 SITE LOCATION FIGURE G-12 COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-13 SITE LOCATION COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-9 SITE LOCATION FIGURE G-14 COMMITMENT & INTEGRITY DRIVE RESULTSWoodard& Curran40 Shattuck Road, Suite 110Andover, Massachusetts 01810866.702.6371 | www.woodardcurran.comFIGURE G-15 SITE LOCATION N S EW STREET TRENCH SHEET 2022 PAVING.DWG12-Apr-2022 10:42 AMPlotted on STREET TRENCH SHEET 2022 PAVING.DWG12-Apr-2022 10:43 AMPlotted on 56939399 719 9 93958993 93 93 9 5 99 878 6 8593 89 87 9994 9 3 96984 6 96 985399 99817 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OADWHI TTI E R R O A D HATHAWAY ROADC O O K E R O A D H OL M ES RO AD MOONHILLROADMID D L E BY ROADH E RIT A G E D RIVE S OL OMONP I E R C E R OADHILL STREETBLUEBERRY LANE WYMANROAD LAWRENCELANE P A R T RID G E R O A D WOODPARKCIRCLETown of Lexington, Massachusetts Pavement Management Program Road Surface Ratings & Repair Categories BURLINGTON WOBURNBEDFORD CONCORD LEXINGTON WINCHESTER LINCOLN MEDFORD ARLINGTON WALTHAM BELMONT CAMBRIDGEWESTON N S EW DRAFT Issue Date: February 16, 2021 This Map is Intended for Planning Purposes Only 0 0.50.25 Miles Date of Inspections: Fall 2021 (1/2 Network) Repair Category No Maintenance Required (94-100) Routine Maintenance (80-94) Preventative Maintenance (65-80) Minor Rehabilitation (45-65) Major Rehabilitation (0-45) Non-Inspected Roadways State Other (Private, Town Unaccepted, etc) 4 §¨¦95 2A 2A §¨¦95 2 2A 2A 4 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 G.4: BATT Credit Calculations JONAS CLARKE MIDDLE SCHOOL RETROFIT BATT REDUCTION CALCULATIONS State MASSACHUSETTS Municipality LEXINGTON Permit Type MS4 Permit Number Major Watershed CHARLES TP Load Reduction Target N/A TN Load Reduction Target N/A TSS Load Reduction Target N/A Table 1. Project Summary Credit for LEXINGTON, MASSACHUSETTS Project Type Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Structural 2.66 22.62 786.84 Non-Structural 0 0 0 Land Use Conversion 0 0 0 Total 2.66 22.62 786.84 Table 2. Structural Project Summary for LEXINGTON, MASSACHUSETTS Project ID BMP Type BMP Storage Capacity (ft3)/ Filter Depth (in.) Phosphorus BMP Efficiency (%) Nitrogen BMP Efficiency (%) Sediment BMP Efficiency (%) Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Impervious Area Treated (ac) Runoff Depth (in.) 17 Stedman ENHANCED BIOFILTRATION 6008 70.2 70.43 97.88 2.66 22.62 786.84 2.13 0.78 Table 3. Non-Structural Project Summary for LEXINGTON, MASSACHUSETTS There are no non-structural BMPs. BOWMAN ELEMENTARY SCHOOL RETROFIT BATT REDUCTION CALCULATIONS State MASSACHUSETTS Municipality LEXINGTON Permit Type MS4 Permit Number Major Watershed CHARLES TP Load Reduction Target N/A TN Load Reduction Target N/A TSS Load Reduction Target N/A Table 1. Project Summary Credit for LEXINGTON, MASSACHUSETTS Project Type Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Structural 5.73 51.06 1956.11 Non-Structural 0 0 0 Land Use Conversion 0 0 0 Total 5.73 51.06 1956.11 Table 2. Structural Project Summary for LEXINGTON, MASSACHUSETTS Project ID BMP Type BMP Storage Capacity (ft3)/ Filter Depth (in.) Phosphorus BMP Efficiency (%) Nitrogen BMP Efficiency (%) Sediment BMP Efficiency (%) Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Impervious Area Treated (ac) Runoff Depth (in.) Porous Pavement POROUS PAVEMENT 12 62.00 76.00 92.00 0.099 1.03 31.25 0.09 N/A Gravel Wetland GRAVEL WETLAND 23572 63.57 71.85 98.28 5.63 50.03 1924.86 4.39 1.32 Table 3. Non-Structural Project Summary for LEXINGTON, MASSACHUSETTS There are no non-structural BMPs. REGIONAL RETROFIT BATT REDUCTION CALCULATIONS State MASSACHUSETTS Municipality LEXINGTON Permit Type MS4 Permit Number Major Watershed CHARLES TP Load Reduction Target N/A TN Load Reduction Target N/A TSS Load Reduction Target N/A Table 1. Project Summary Credit for LEXINGTON, MASSACHUSETTS Project Type Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Structural 50.32 302.53 21628.35 Non-Structural 0 0 0 Land Use Conversion 0 0 0 Total 50.32 302.53 21628.35 Table 2. Structural Project Summary for LEXINGTON, MASSACHUSETTS Project ID BMP Type BMP Storage Capacity (ft3)/ Filter Depth (in.) Phosphorus BMP Efficiency (%) Nitrogen BMP Efficiency (%) Sediment BMP Efficiency (%) Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Impervious Area Treated (ac) Runoff Depth (in.) Regional 1 - Munroe GRAVEL WETLAND 6700 28.55 35.55 64.57 4.87 43.05 2503.87 7.889 0.23 Regional 2 - Philip Road PROPRIETARY - 59 - - 7.47 - - 5.682 - Regional 3 – Green Lane INFILTRATION BASIN 3253 50.33 67.83 80.25 7.72 71.21 2824.67 6.011 0.15 Regional 4 - Valleyfield WET POND/CREATED WETLAND 40713 34.36 21.46 56.48 18.51 85.32 9944.35 31.499 0.36 Regional 5 - Valleyfield GRAVEL WETLAND 13261 22.8 27.98 55.06 11.75 102.95 6355.46 23.671 0.15 Table 3. Non-Structural Project Summary for LEXINGTON, MASSACHUSETTS There are no non-structural BMPs. Table 4. Land Use Conversion Project Summary for LEXINGTON, MASSACHUSETTS There are no land use conversion projects. State MASSACHUSETTS Municipality LEXINGTON Permit Type MS4 Permit Number Major Watershed CHARLES TP Load Reduction Target N/A TN Load Reduction Target N/A TSS Load Reduction Target N/A Table 1. Project Summary Credit for LEXINGTON, MASSACHUSETTS Project Type Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Structural 5.17 57.83 1626.05 Non-Structural 0 0 0 Land Use Conversion 0.12 0.79 25.96 Total 5.29 58.62 1652.01 ROADWAY RETROFIT BATT REDUCTION CALCULATIONS Table 2. Structural Project Summary for LEXINGTON, MASSACHUSETTS Project ID BMP Type BMP Storage Capacity (ft3)/ Filter Depth (in.) Phosphorus BMP Efficiency (%) Nitrogen BMP Efficiency (%) Sediment BMP Efficiency (%) Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Impervious Area Treated (ac) Runoff Depth (in.) Ewell Road INFILTRATION TRENCH 576 69.45 89.67 88.11 0.71 6.67 203.13 0.51 0.31 INFILTRATION TRENCH 468 93.46 98.49 100 0.35 2.66 83.54 0.18 0.63 Benjamin Road INFILTRATION TRENCH 648 43.65 73.71 63.06 1.06 12.92 342.53 1.203 0.15 Valleyfield Street INFILTRATION TRENCH 720 37.75 70.14 57.98 1.01 13.64 347.54 1.29 0.15 Crosby Road INFILTRATION TRENCH 576 29.87 63.44 47.73 0.83 12.79 298.26 1.39 0.11 Clematis Road ENHANCED BIOFILTRATION 1247 75.38 74.5 98.88 0.50 3.92 151.14 0.25 1.01 Elena Road ENHANCED BIOFILTRATION 1007 77.26 76.1 99.16 0.39 2.76 111.96 0.26 1.08 Piper Road INFILTRATION TRENCH 432 88.62 97.44 99.44 0.30 2.37 74.55 0.16 0.64 Allen Road BIOFILTRATION 26.4 21.31 13.65 60.62 0.02 0.1 13.4 0.04 0.16 Table 3. Non-Structural Project Summary for LEXINGTON, MASSACHUSETTS There are no non-structural BMPs. Table 4. Land Use Conversion Project Summary for LEXINGTON, MASSACHUSETTS Project ID Removed Phosphorus Load (lb/yr) Removed Nitrogen Load (lb/yr) Removed Sediment Load (lb/yr) Impervious Area Treated (ac) Clematis Road (Land Conversion) 0.06 0.38 12.7 0.0365 Elena Road (Land Conversion) 0.06 0.4 13.25 0.0365 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX H: PRIVATE SCM INSPECTION FORMS Page 1 of 3 Lexington Detention Basin Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Detention Basin Page 2 of 3 Lexington Detention Basin Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Detention Basin Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Infiltration Basin Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Infiltration Basin Page 2 of 3 Lexington Infiltration Basin Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Infiltration Basin Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Infiltration Chamber Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. * Do not enter subsurface structures without evaluation of hazards, proper training, and confined space entry procedure. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Infiltration Chamber Page 2 of 3 Lexington Infiltration Basin Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Infiltration Basin Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Infiltration Trench / Dry Well / Leaching Catch Basin / Leaching Galley Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. * Do not enter subsurface structures without evaluation of hazards, proper training, and confined space entry procedure. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Infiltration Trench / Dry Well / Leaching Catch Basin / Leaching Galley Page 2 of 3 Lexington Infiltration Trench / Dry Well / Leaching Catch Basin / Leaching Galley Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Infiltration Trench / Dry Well / Leaching Catch Basin / Leaching Galley Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Biofiltration / Bioretention / Rain Garden / Tree Well / Enhanced Biofiltration with ISR Inspection Form Biofiltration / Bioretention / Rain Garden / Tree Well / Enhanced Biofiltration with Internal Storage Reservoir (ISR) Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Page 2 of 3 Lexington Biofiltration / Bioretention / Rain Garden / Tree Well / Enhanced Biofiltration with ISR Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Biofiltration / Bioretention / Rain Garden / Tree Well / Enhanced Biofiltration with ISR Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Gravel/Constructed Wetland Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Gravel / Constructed Wetland Page 2 of 3 Lexington Gravel/Constructed Wetland Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Gravel/Constructed Wetland Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Porous Pavement Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Porous Pavement Page 2 of 3 Lexington Porous Pavement Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Porous Pavement Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Sand Filter Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. * Do not enter subsurface structures without evaluation of hazards, proper training, and confined space entry procedure. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Sand Filter Page 2 of 3 Lexington Sand Filter Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Sand Filter Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Vegetated Swale Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Vegetated Swale Page 2 of 3 Lexington Vegetated Swale Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Vegetated Swale Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Page 1 of 3 Lexington Wet Pond Inspection Form Inspection & Maintenance Record Owner Name: Owner Phone Number: Owner Address: Inspection Date: Maintenance Date: Inspector: Maintained By: SCM Location: Type of Maintenance (see below): Weather: Date of Previous Maintenance: Inspection & Maintenance Recommendations Procedure Objective Frequency 1. Mowing, Landscaping, and Vegetation Management Minimize establishment / takeover of non- intentional woody vegetation. Mowing specifically for embankment / side slopes / areas where bioretention plantings are not present. Trim vegetation and remove weeds. Maintain mulch layer to retain soil moisture. Divide plants as needed to avoid overcrowding and reduce blooms. Mow / landscape at least twice per year and remove mowed material / clippings. Apply mulch layer in Spring and as needed. Remove dead vegetation annually. 2. Debris and Litter Removal Remove for aesthetics and to mitigate contribution of downstream floatables. As needed by inspection. Monthly debris and litter removal. 3. Sediment Removal Maintain flow capacity. Inspect and remove sediment, particularly at pipe discharge. Inspect quarterly for the first year. Establish a specific schedule based on first year accumulations. 4. Structural Integrity Minimize erosion and channelization of stormwater. Inspect for signs of scouring, particularly near high velocity areas. After large storms (2.5 inches of rainfall), but not less than twice per year. 5. Water Level Inspection Inspect water level in unit. System should be drained completely 72 hours after a storm event. At a minimum inspect twice a year at least 72 hours after storm event. Town Use Only SCM ID: _____________________________ Date Received: ______________________ Date Recorded: _____________________ Wet Pond Page 2 of 3 Lexington Wet Pond Inspection Form Condition Assessment Circle all that apply: Does SCM Appear to Be Working Properly?Yes No Is Maintenance Required? Yes No Maintenance Access No Direct Access / Limited Access Foot ATV Truck No Access Restrictions Is Underdrain Working Properly? Yes No Not Applicable Unknown Standing Water in System?Yes No Evidence of Flooding / Overtopping?Yes No Emergency Spillway Good Condition Erosion Excess Vegetation Other: _______ Maximum Sediment Depth (inches) _________________ inches *Push ruler into sediment deposits until flush with surface elevation of the designed system. Pretreatment System Forebay Oil / Water Separator Proprietary Settling / Swirl Chamber Sediment Chamber Not Applicable Pretreatment System Condition Good Condition Heavy Sediment Accumulation Slight Sediment Accumulation Undesirable Woody Plants Not Applicable Inlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Good Condition Erosion Pipe Damaged Not Applicable Outlet Control Structure Good Condition Cracked Exposed Steel Corroded Clogged Not Applicable Rodent Control Needs Work Holes >3”Holes <3”None Deposits None Oil/Grease Grass Clippings/ Compost Trash/ Debris Sediment Other: _______ Vegetation None Healthy Unhealthy Sparse Undesirable Woody Plants Erosion None Inlet/Outlet Erosion Embankment/ Side Slope Erosion Channeling/ Depressions Displaced Riprap Other: _______ Does System Drain Within 72-Hours? Yes No Page 3 of 3 Lexington Wet Pond Inspection Form Additional Comments: Photos / Files / Attachments:Photo: Description: Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 APPENDIX I: IMPLEMENTATION COST I.1: Non-Structural Cost I.2: O&M Cost I.3: Planned Structural Cost Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 I.1: Non-Structural Cost Non-Structural Cost Estimate June 2023 Annual Town-Wide Cost 400,000$ Town-Wide Municipal Road Length (LF)696954 CRW Municipal Road Length (LF)144214 Percent CRW vs. Town-Wide 20.7% Street Sweeping CRW Cost 82,768$ Annual Town-Wide Cost 85,000$ Town-Wide Municipal Catch Basin Count 5541 CRW Municipal Catch Basin Count 1140 Percent CRW vs. Town-Wide 20.6% Street Sweeping CRW Cost 17,488$ Total CRW Non-Structural Cost 100,256$ Street Sweeping Catch Basin Cleaning Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 I.2: O&M Cost Estimated Operations and Maintenance Cost Lexington, MA PCP June 2023 Supervisor Hours Operator Hours Laborer Hours $55.00 $41.00 $40.00 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Basin - Debris Removal Twice per Year 12 1 12 $480 Dump Truck, Jet/Vac Truck 1 $4,416 Basin - Plant Maintenance/Mowing Quarterly 4 1 4 $160 Pickup Truck, Saws, Weedwhacker 1 $144 Basin - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Basin - Repairs and/or Infiltration Restoration Every Tenth Year 0.1 8 16 2.4 $97 Rototiller, Dump-truck, Backhoe 16 $373 Subtotal per System 4.0 8.8 33.6 46.4 $1,925 28.0 $10,945 Total 24.0 52.8 201.6 278.4 $11,549 168.0 $65,669 $77,218 Diversion Structures - Sediment Removal Twice per Year 2 2 2 8 $324 Pickup Truck, Jet/Vac Truck 2 $1,164 Diversion Structures - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Isolator Row - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Isolator Row - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Infiltration Chambers - Visual Inspection Annually 1 1 1 $55 Pickup Truck 1 $5 Subtotal per System 7.0 20.0 36.0 63.0 $2,645 22.0 $13,131 Total 49.0 140.0 252.0 441.0 $18,515 154.0 $91,917 $110,432 Trench - Sediment/Floatable Removal Twice per Year 2 4 8 24 $968 Pickup Truck, Jet/Vac Truck 8 $4,656 Trench and Monitoring Well - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Trench - Repairs and/or Infiltration Restoration Every Tenth Year 0.1 12 24 3.6 $145 Pickup Truck, Dump-truck, Backhoe 24 $622 Subtotal per System 2.0 9.2 18.4 29.6 $1,223 33.0 $5,340 Total 22.0 101.2 202.4 325.6 $13,455 363.0 $58,736 $72,191 Porous Pavement - Restoration/Sediment Removal Twice per Year 2 8 16 48 $1,936 Jet/Vac Truck 16 $8,320 Porous Pavement - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Subtotal per System 1.0 16.0 32.0 49.0 $1,991 17.0 $8,351 Total 3.0 48.0 96.0 147.0 $5,973 51.0 $25,053 $31,026 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Basin - Debris Removal Quarterly 12 1 12 $480 Dump Truck, Jet/Vac Truck 1 $4,416 Basin - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Basin - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Rototiller, Dump-truck, Backhoe 16 $373 Subtotal per System 2.0 8.8 29.6 40.4 $1,655 27.0 $10,739 Total 0 0 0 0 $0 0 $0 $0 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Basin - Debris Removal Monthly 12 1 12 $480 Dump Truck, Jet/Vac Truck 1 $4,416 Basin - Mulch Annually 1 1 1 $40 Pickup Truck, Dump-truck, Bobcat, Trailer 1 $187 Basin - Plant Maintenance/Mowing Quarterly 4 1 4 $160 Pickup Truck, Saws, Weedwhacker 1 $316 Basin - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Basin - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Rototiller, Dump-truck, Backhoe 16 $373 Subtotal per System 2.0 8.8 34.6 45.4 $1,855 29.0 $11,242 Total 4.0 17.6 69.2 90.8 $3,710 58.0 $22,484 $26,193 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Basin - Debris Removal Annually 1 1 1 $40 Dump Truck, Jet/Vac Truck 1 $368 Basin - Mulch Annually 1 1 1 $40 Pickup Truck, Dump-truck, Bobcat, Trailer 1 $264 Basin - Plant Maintenance/Mowing Quarterly 4 1 4 $160 Pickup Truck, Saws, Weedwhacker 1 $144 Basin - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Basin - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Rototiller, Dump-truck, Backhoe 16 $373 Subtotal per System 2.0 8.8 23.6 34.4 $1,415 29.0 $7,099 Total 6 26.4 70.8 103.2 $4,244 87.0 $21,296 $25,541 Diversion Structures - Sediment Removal Twice per Year 2 2 2 8 $324 Pickup Truck, Jet/Vac Truck 2 $1,164 Diversion Structures - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pretreatment Structure - Sediment Removal Annually 0.5 4 8 6 $242 Dump Truck, Jet/Vac Truck 8 $1,472 Pretreatment Structure - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Wetland - Debris Removal Annually 1 4 4 $160 Dump Truck, Jet/Vac Truck 4 $1,472 Wetland - Plant Maintenance Quarterly 4 1 4 $160 Pickup Truck, Saws, Weedwhacker 1 $144 Wetland - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Wetland - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Dump-truck, Backhoe 16 $365 Subtotal per System 4.0 6.8 17.6 28.4 1202.8 34.0 $4,741 Total 16.0 27.2 70.4 113.6 $4,811 136.0 $18,963 $23,774 Diversion Structures - Sediment Removal Twice per Year 2 2 2 8 $324 Pickup Truck, Jet/Vac Truck 2 $1,164 Diversion Structures - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pond - Debris Removal Annually 1 1 1 $40 Dump Truck, Jet/Vac Truck 1 $368 Pond - Inspection Annually 1 1 1 $55 Pickup Truck 1 $31 Pond - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Dump-truck, Backhoe 16 $365 Subtotal per System 3.0 12.8 22.6 38.4 $1,594 30.0 $7,878 Total 0 0 0 0 $0 0.0 $0 $0 Diversion Structures - Sediment Removal Twice per Year 2 2 2 8 $324 Pickup Truck, Jet/Vac Truck 2 $1,164 Diversion Structures - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pond - Debris Removal Annually 1 2 2 4 $162 Dump Truck, Jet/Vac Truck 2 $736 Pond - Plant Maintenance/Mowing Quarterly 4 1 4 $160 Pickup Truck, Saws, Weedwhacker 1 $144 Pond - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Pond - Repairs Every Tenth Year 0.1 8 16 2.4 $97 Dump-truck, Backhoe 16 $365 Subtotal per System 4.0 14.8 27.6 46.4 $1,931 32.0 $8,421 Total 4 14.8 27.6 46.4 $1,931 32.0 $8,421 $10,352 Swale - Debris Removal Annually 1 4 8 12 $484 Dump Truck, Jet/Vac Truck 8 $2,944 Swale - Plant Maintenance/Mowing Quarterly 4 1 4 $160 Pickup Truck, Dump-truck 1 $124 Swale - Inspection Twice per Year 2 1 2 $110 Pickup Truck 1 $62 Subtotal per System 2.0 4.0 12.0 18.0 $754 10.0 $3,130 Total 2 4 12 18 $754 10.0 $3,130 $3,884 Diversion Structures - Sediment Removal Twice per Year 2 2 2 8 $324 Pickup Truck, Jet/Vac Truck 2 $1,164 Diversion Structures - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Pretreatment Structure - Sediment Removal Twice per Year 2 4 8 24 $968 Dump Truck, Jet/Vac Truck 8 $5,888 Pretreatment Structure - Inspection Twice per Year 1 1 1 $55 Pickup Truck 1 $31 Treatment Cartidges - Clean Once per Year 1 4 8 12 $484 Dump Truck, Jet/Vac Truck 8 $2,944 Subtotal per System 2.0 16.0 28.0 46.0 $1,507 17.0 $8,863 Total 4 32 56 92 $3,772 34.0 $17,726 $21,498 Issuing and Tracking Work Orders Weekly 52 4 208 $11,440 N/A 0 $0 Annual Reporting Annually 1 40 40 $2,200 N/A 0 $0 Subtotal per System 248.0 0 0 248.0 $13,640 0.0 $0 Total 248.0 0 0 248.0 $13,640 0.0 $0 $13,640 Total SCMs 18 23 Section A Sum $415,748 Annual Hrs. by Position 378 432 1,002 Hourly Rate by Position $55.00 $41.00 $40.00 Annual Cost by Position $20,790 $17,712 $40,080 Total Annual Labor Cost $78,600 V&ME Unit Cost (per Hour) Pickup Truck $31.00 Rototiller $5.00 Trailer $5.00 Mower $5.00 Pretreament Waste (e.g., sediment) Disposal Cost $50 2 $98 Weedwhacker $5.00 Section B Sum $1,000 Saws $5.00 Jet/Vac Truck, CCTV Rig $260.00 Dump-truck $108.00 Category Estimated Value Assumed Annual Rate Annual Cost Backhoe $120.00 Stormwater Infrastructure Replacement (Every 30 Years)$9,800,000 3%$326,667 Bobcat $43.00 Plantings Replacement (Every 5 Years)$12,576 20%$2,515 Section C Sum $330,000 Treated Impervious Drainage Area Area (acre) TSS PLER (lb/yr) (Commercial) Generated TSS Load Removed TSS (lb/yr) (50% reduction) Existing SCM 10.8 4,076 2,038 Annual Subtotal (Section A, B, and C Sums)$747,000 Planned SCM - Parcel Regional 10 3,774 1,887 Contingency 30%$225,000 Overhead and Profit (if Contracted) or Administration 20%$149,000 Annual Total $1,121,000 Number of SCMs Unit Cost Total Cost Diversion Structures 12 $50,000 $600,000 Pretreatment Structures 23 $75,000 $1,725,000 Infiltration Basin 6 $100,000 $600,000 Infiltration Chambers 7 $500,000 $3,500,000 Infiltration Trenches/Dry Wells 11 $75,000 $825,000 Porous Pavement 3 $500,000 $1,500,000 Sand Filter 0 $100,000 $0 Biofiltration/Bioretention/Rain Garden 2 $100,000 $200,000 Enhanced Biofiltration with ISR 3 $100,000 $300,000 Gravel/Constructed Wetland 4 $100,000 $400,000 Wet Pond 0 $100,000 $0 Dry Pond 1 $100,000 $100,000 Vegetated Swale 1 $50,000 $50,000 Seed (per grassed SCM)13 $50 $2,340 Plantings (per planted SCM) (1 plant per 100 SF)13 $100 $4,680 Mulch (per biofiltration system) (2" mulch depth)5 $50 $5,556 Seed cost = average SCM area (3,600 SF) * seed mix rate of 1lb/1000SF * $50/lb Plantings cost = average SCM area (3,600 SF) * 1 plant/1000 SF * $100 per plant Mulch cost = average SCM area (3,600 SF) * 2" mulch depth * $50/CY mulch Average SCM Area (SF) = 3,600 Lexington's Total Cost by SCM Type Section B Reference Section C Reference Section A - Reoccurring Labor and Equipment O&M Costs Labor Support Section A Reference - Vehicles and Mechanical Equipment Rates Total Cost Estimated Quantity Per Year (Tons) Section B - Reoccurring Fees and Bills Unit CostCategory Section C - Equipment and Plantings Replacement Costs Annual Cost 377.4Infiltration Chambers7 0 101 Infiltration Trench / Dry Well15 Infiltration BasinV&ME Hrs. Annualized CostExisting Planned Activity Frequency Annual Multiplier Labor DurationNumber of Municipal Systems Total Hours Per Year Annual Cost Vehicles and Mechanical Equipment (V&ME, see hourly rates below table)Enhanced Biofiltration with ISR0 3Porous Pavement2 1 Sand Filter0 0SCM TypeDry Pond1 0 Vegetated Swale1 0 0 4 Gravel / Constructed WetlandWet Pond0 0Biofiltration/Bioretention/ Rain Garden1 1 Proprietary Filter Catridge System0 2 Program Management0 1 Lexington, MA (0227871.12) Woodard & Curran, Inc. Phase 1 Phosphorus Control Plan June 2023 I.3: Planned Structural Cost Estimate Recap - Stormwater Improvement Concept Estimates Recap - With Taxes and Insurance ,Indirect Costs are Spread Group 1: Area Group 2: BMP Type Estimator : Kris Rosner Project Size : 0 SQFT Description Quantity UM Lab.Total Mat.Total Sub.Total Eqp.Total Process Equip. Tot.UnitCost TotalCost C:\Users\krosner\227871 Stormwater Concept Estimates JUN2022.est Page 1 6/28/2022 11:21 AM Munroe Road Gravel Wetland 117,861 93,922 4,472 46,342 262,597 * Total Munroe Road 117,861 93,922 4,472 46,342 262,597 Green Lane Infiltration Basin 63,352 52,357 21,966 137,676 * Total Green Lane 63,352 52,357 21,966 137,676 Valleyfield Street 1 Constructed Wetland 143,047 33,808 62,929 239,784 * Total Valleyfield Street 1 143,047 33,808 62,929 239,784 Valleyfield Street 2 Gravel Wetland 205,483 157,362 6,708 77,087 446,639 * Total Valleyfield Street 2 205,483 157,362 6,708 77,087 446,639 Budget Estimate Summary Date:6/30/2023 Stormwater Improvement Concept Estimates Time:8:55 AM Woodard & Curran Project No.:227871 41 Hutchins Drive Portland, Maine 04102 Labor Material Const Equip Subcontract Temp Matl Proc Equip Other Totals Direct Construction Cost % Base Labor $108,728 $151,057 $76,677 $59,550 $0 $503,000 $0 $899,011 Labor Burden 45.00%$48,928 $48,928 Labor Fringes $65,235 $65,235 Labor Manhours 2,644 Material Sales Tax 0.00%$0 $0 Const Equip Transportation 3.50%$2,684 $2,684 Subcontractor Bonds 0.00%$0 $0 Temporary Material Sales Tax 0.00%$0 $0 Process Equipment Tax/Freight 0.00%$0 $0 Other Markup 0.00%$0 $0 Gross Construction Cost $222,891 $151,057 $79,361 $59,550 $0 $503,000 $0 $1,015,858 General Liability Insurance 0.85%$11,390 $11,390 Builders' Risk Insurance 0.15%$2,010 $2,010 Overall Contractor Overhead & Gen'l Cond.0.00%18.00%18.00%18.00%18.00%18.00%18.00%18.00% $0 $40,120 $29,602 $14,285 $10,719 $0 $90,540 $0 $185,266 Trade Contractor Profit 0.00%10.00%10.00%10.00%10.00%10.00%10.00%10.00% $0 $22,289 $16,446 $7,936 $5,955 $0 $50,300 $0 $102,926 P&P Bonds $22,550 $22,550 $22,550 Total Construction Cost $285,300 $233,054 $101,582 $76,224 $0 $643,840 $0 $1,340,000 Design / Engineering ($50K x 3 sites)$150,000 $150,000 Permitting ($25K x 3 sites)$75,000 $75,000 Geotech. Investigation ($10K x 3 sites)$30,000 $30,000 Survey ($15K x 3 sites)$45,000 $45,000 Construction Admin.($15K x 3 sites)$45,000 $45,000 Bidding ($5K x 3 sites)$15,000 $15,000 Sub-Total $1,700,000 Design Contingency 25%$425,000 Sub-Total $2,125,000 Owner Contingency 20%$425,000 Project Total $2,550,000 Estimate Recap - Stormwater Improvement Concept Estimates Recap - With Taxes and Insurance ,Indirect Costs are Spread Group 1: Area Group 2: BMP Type Estimator : Kris Rosner Project Size : 0 SQFT Description Quantity UM Lab.Total Mat.Total Sub.Total Eqp.Total Process Equip. Tot.UnitCost TotalCost C:\Users\krosner\227871 Stormwater Estimates JUN2023.est Page 1 6/30/2023 08:58 AM Philip Road Separation and Filtration 101,726 41,268 15,061 33,009 1,152,179 1,343,243 * Total Philip Road 101,726 41,268 15,061 33,009 1,152,179 1,343,243 Jonas Clarke Middle School Enhanced Biofiltration System 86,815 55,837 2,824 23,564 110,449 279,489 * Total Jonas Clarke Middle School 86,815 55,837 2,824 23,564 110,449 279,489 Bowman Elementary School Gravel Wetland 345,110 238,755 47,066 136,572 767,503 Permeable Pavement 25,847 43,321 84,531 6,066 159,765 * Total Bowman Elementary School 370,958 282,076 131,597 142,638 927,268 Total Estimate 559,498 379,181 149,482 199,211 1,262,627 2,550,000 1.45 0.51 0.93 Infiltration Trench 69% 0.714Proposed infiltration trench with piping running south from existing catch basin, estimated 576 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate0.54 0.18 0.35 Infiltration Trench 93% 0.348Proposed infiltration trench with piping running south from existing catch basin, estimated 468 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate2 Benjamin Road 42 A 3.43 1.20 2.11 Infiltration Trench 44% 1.057 $93,361Proposed infiltration trench with piping running south from existing catch basin, estimated 648 CF storage volume in subsurface stone, assume 2.41 in/hr infiltration rate3 ***Valleyfield Street 37 **A 5.94 1.29 4.65 Infiltration Trench 38% 1.007 $95,401Proposed infiltration trench with piping running south from existing catch basin, estimated 720 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate4 Crosby Road 25 **A 3.59 1.39 2.21 Infiltration Trench 30% 0.832 $91,321Proposed infiltration trench with piping running south from existing catch basin, estimated 576 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate5 Clematis Road 41 D 0.73 0.25 0.48 Enhanced Biofiltration (w/ ISR) 76% 0.504 $119,144Proposed enhanced biofiltration system (w/ ISR) in proposed roundabout in the cul-de-sac area, estimated 1250 CF storage volume. Please note ROM cost excludes any potential utility relocation.6 Elena Road 45 C/D 0.26 0.26 0.00 Enhanced Biofiltration (w/ ISR) 77% 0.390 $110,647Proposed bioretention basin (no underdrain) in proposed roundabout in the cul-de-sac area, with estimated 1007 CF storage volume7 Piper Road 45 **A 0.82 0.16 0.66 Infiltration Trench 89% 0.296 $87,241Proposed infiltration trench with piping running south from existing catch basin, estimated 432 CF storage volume in subsurface stone, assume 1.02 in/hr infiltration rate8 Allen Street 42 D 0.09 0.04 0.05 Biofiltration 21% 0.021 $75,925 Proposed biofiltration/tree box filter system to replace existing catch basinTotal5.169 $777,622Notes and AssumptionsAll TP load calcluations assume Medium-Density Residential land cover useDrainage area defined as catchment for individual catch basin/inlet for a Stormwater Control MeasureRemoval efficiency for each SCM determined by performance curves (MS4 General Permit Appendix F Attachment 3)Ranking in order of highest TP reduction potentialCost estimate based on unit cost from 2020 "mixed" development land costs including materials, installation, and design from UNHSC Performance Curves *Repair Category Number in reference to 'Major Rehabilitation' category based on Town's Road Surface Ratings & Repair Categories from Pavement Management Program, issued February 16, 2021**Soil group requires confirmation via test pits***Valleyfield Street roadway retrofit may be replaced by Regional Retrofit Concept #4 or #5 due to overlap in catchment areaSoil GroupEwell Avenue $104,582Municipal Roadway Retrofit OpportunitiesRankTotal Catchment Area (ac)Impervious Area (ac)Pervious Area (ac)Street*Repair Category NumberProposed Stormwater Control Measure (SCM)TP Reduction (lb/yr)Removal Efficiency1 34 ANotesROM Cost Estimate ($) woodardcurran.com