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HomeMy WebLinkAboutSW report STORMWATER MANAGEMENT REPORT CHASE BROOK PARK RESTORATION & PEDESTRIAN BRIDGE PROJECT TOWN OF YARMOUTH November 2023 Prepared for: Town of Yarmouth Prepared by: COASTAL ENGINEERING CO., INC. 260 Cranberry Highway Orleans, MA 02653 TABLE OF CONTENTS 1. Stormwater Management System Description 2. Massachusetts Stormwater Management Design Standards 3. Owner & Responsible Party 4. Schedule of Inspection and Maintenance of System 5. Long Term Pollution Prevention Plan 6. Emergency Spill Cleanup Plan 7. APPENDICES APPENDIX A – Checklist for Stormwater Report DZ-1 -Plan Showing Pre-Development Drainage Areas DZ-2 -Plan Showing Post-Development Drainage Areas Soil Report HydroCAD Report Stormwater Management System Description The subject site is three parcels of land located at 261/275/281 Route 28 in Yarmouth, Massachusetts. The project area is abutted by residential properties to the West, commercial properties to the East, Route 28 to the North, and Mill Creek to the South. The westernmost lot, 261 Route 28 (Chase Brook Park), consists of a 0.2+/- Acre parking area and 0.9+/- Acre town park. The eastern most lot 281 Route 28 (Mill Creek Park) consists of a 0.2+/- Acre parking area and 1.5+/- Acre town park. The middle lot at 275 Route 28 was formerly the site of the Yankee Village Motel. The motel and associated site hardscape, sewage disposal systems, and drainage systems were demolished and removed from the site after the Town purchased the property in 2019. One of the goals of this project is to complete the improvement plan for this property that began with the property purchase in 2019 by removing the remaining demolition debris and invasive species, planting native and ecologically viable species, and constructing a walkway trail network that is designed to connect the two (2) existing town parks located on either side of the former motel property to create one continuous park. The topography of the site for the proposed continuous singular town park ranges from elevation -1 feet (NAVD88) along the centerline of Chase Brook and along Mill Creek to an elevation of 9 feet (NAVD88) at both of the existing parking lots located along the northern edge of the property. The proposed site improvement includes construction of semi- permeable stabilized aggregate ADA compliant walkways to connect the parcels, a pedestrian bridge spanning Chase Brook, a semi-permeable stabilized aggregate picnic area adjacent to the parking lot of the Chase Brook parcel, man made and natural seating options for people to rest and enjoy the park, and invasive vegetation removal and restoration with native vegetation. Presently, the motel site is vegetated with woods, invasive species and demolition debris from the former hotel. Both the Mill Creek Park and Chase Brook Park portions of the project site have impermeable walkways and areas of invasive species. The two parks are isolated from each other with the only current connection being a sidewalk along Route 28. Both of the parks include parking lots without formal drainage systems. Based on the existing site topography, it appears that stormwater runoff flows across the vegetated areas consisting of native grasses and plants where it naturally infiltrates into the soil. Tables 1.0 provides a tabulation for pre-development and post-development of impermeable/semi-permeable areas within the project areas. Table 1.0 Pre-Development and Post-Development impermeable/semi-permeable surface areas (SF) - Existing Proposed Net Change Parking Lot Paved Walkways Paved Picnic Area Parking Lot Gravel Walkways& Picnic Area Paved Walkway & Picnic Areas Bridge Abutments Parking Lot Gravel Walkways & Picnic Area Paved Walkway & Picnic Areas Abutments Total Chase Brook Parcel 7,015 1,311 550 7,015 3,540 0 24 0 +3,540 -1,861 +24 +1,703 Yankee Village Parcel 0* 0* 0 0 3,820 0 24 0 +3,820 0* +24 +3,844* Mill Creek Parcel 6,481 1,890 228 6,481 2,480 228 0 0 +2,480 -1,890 0 +590 *The Yankee Village Parcel was previously fully developed with a motel with associated paved driveways and parking areas. Per the project description posted on the Town of Yarmouth website titled, “Yankee Village Property Restoration (275 Route 28) dated July 2022, it is reported that the estimated area of impervious surfaces that existed prior to demolition was approximately 1 acre. Therefore, the initial demolition phase of this park project has already provided a substantial reduction in runoff from impervious surfaces. This reduction in runoff from impervious surfaces resulted in significant water quality benefits to the nearby environmental resource areas. Table 2.0 below provides a comparison summary of the estimated runoff conditions pre- development vs. post-development for the 2 year 24-hour and 10 year 24-hour storm events. These calculations were developed utilizing HydroCAD stormwater modeling software. A full HydroCAD report can be found in Appendix A of this report. As shown in the calculations provided below the post development condition of the proposed project will result in a decrease in runoff on this project site. Any new runoff generated within the project site will be managed by directing the runoff toward vegetated meadow/ restored native vegetation areas for natural onsite infiltration. Table 2.0 Comparison Summary of Estimated Runoff Conditions Pre-Development vs. Post development: Pre-development 2YR Storm Post-development 2-Yr Storm Pre-development 10-Yr Storm Post-development 10-Yr Storm Chase Brook Park 0.35 cfs 0.14 cfs 0.73 cfs 0.45 cfs Yankee Village* 2.54 cfs 0.00 cfs 3.70 cfs 0.01 cfs Mill Creek Park 0.16 cfs 0.02 cfs 0.57 cfs 0.16 cfs *The Yankee Village Parcel was previously fully developed with a motel with associated paved driveways and parking areas. Calculations shown on Table 2.0 include 38,000 s.f. of impervious coverage (e.g., building, paved parking areas, and pool area) in the land use analysis for Pre-Development site conditions. In summary, at the Chase Brook Park and Mill Creek Park sites replacement of existing impervious paved/Brick walkways with stabilized aggregate walkways, and improvement of the plant community in the surrounding vegetated areas will greatly reduce the runoff generated on the site. Runoff generated in the 2-year and 10-year 24 hour storm events will be able to naturally infiltrate into the vegetated meadows that will be established throughout the site as a result of this project. At the Yankee Village motel site, runoff has been significantly reduced as a result of removal of the motel building, parking areas, and pool area. The addition of stabilized aggregate walkways and improvement of the plant community in the vegetated areas surrounding the walkway in the post-development conditions will result in a di minimus amount of runoff generated on the Yankee Village Parcel in the 2-year and 10-year 24 hour storm events. Massachusetts Stormwater Management Design Standards The following is a description of how the proposed project meets the Massachusetts Stormwater Handbook design Standards: Standard 1: No new untreated discharges This standard is met since there are no new untreated stormwater discharges proposed. Standard 2: Maintain Pre-development peak discharge rate This standard has been met. Overall, removal of the motel building with associated driveways and parking has resulted in a significant reduction in impervious coverage on this project site. Additionally, by removing impervious paved walkways on both the Mill Creek Park parcel and on the Chase Brook Parcel and replacing them with walkways that are a semi-permeable stabilized gravel there is an overall reduction in the peak discharge rate post development. Standard 3: Groundwater Recharge This standard has been met. Overall, removal of the motel building with associated driveways and parking has resulted in a significant reduction in impervious coverage on this project site. Additionally, by removing invasive plants and restoring areas previously occupied by invasive plants, impervious coverage and/or bare of vegetation with native plant vegetation there will be improved ability for plants and soil to absorb or infiltrate precipitation falling on the site. This will enhance groundwater recharge at this site. Standard 4: Water Quality Overall, removal of the motel building with associated driveways and parking has resulted in a significant reduction in impervious coverage that was contributing to runoff on this project site. Removal of the parking areas benefits the environment by removing a runoff source that could potentially include roadway pollutants. Therefore, the reduction in impervious coverage on this project site has resulted in a substantial water quality improvement. Standard 5: Land uses with higher pollutant loads This standard is not applicable. Standard 6: Stormwater discharges within the Zone II or Interim Wellhead protection area of a public water supply, and stormwater discharges near or to any critical area This standard is not applicable. Standard 7: Redevelopment Overall, removal of the motel building with associated driveways and parking has resulted in a significant reduction in impervious coverage and runoff generated on this project site. Runoff generated on this site from the proposed improvements that include gravel walkways and pedestrian bridge support abutments is a de minimis amount that will naturally infiltrate in the surrounding native vegetation. Standard 8: Construction Erosion Control Plan This project will be subject to the NPDES Construction General Permit. A SWPPP will be submitted to EPA and the Conservation Commission prior to any land disturbance. Standard 9: Long Term Operation and Maintenance Plan Overall, there is a reduction in impervious coverage on this property. No new formal stormwater management BMP’s are proposed. Any new stormwater runoff generated on this site (di minimus amount) will naturally infiltrate on site. Standard 10: Illicit Discharges This standard is met since there are no known illicit discharges at this site and no illicit discharges are proposed. Owner and Responsible Party The owner and responsible party for Stormwater Pollution Control at 261/275/281 Route 28 in Yarmouth, Massachusetts: Owner: Town of Yarmouth Attn: Nathan Whetten, Senior Project Manager Phone: (508) 398-2231 Ext. 1252 Operator: Town of Yarmouth Attn: Nathan Whetten, Senior Project Manager Phone: (508) 398-2231 Ext. 1252 Schedule of Inspection and Maintenance of Stormwater Management Systems  Periodically the installed paths shall be inspected for evidence of erosion. Any areas of visible erosion shall be addressed.  Periodically the slope around the bridge abutments should be inspected for evidence of erosion. Any erosion observed should be addressed. Date Time O&M log form records to be maintained by property manager for a minimum of three years Repair NeededGood Repaired Date O & M Log Form Inspector Initials Item Inspected Condition Clean-out Needed Long Term Pollution Prevention Plan Description of Pollutant Sources: Source Control Best Management Practices  Trash receptacles shall be covered. If leaks are found, the receptacle shall be replaced. Trash receptacle areas shall be kept clear of debris.  Good housekeeping measures shall be implemented throughout the site in order to keep the driveways, parking lot areas, and paths clean of debris.  Regularly inspect driveways and parking areas for sediment and debris. As necessary, remove debris and any other potential stormwater pollutants.  The use of winter de-icing sand and salt materials in parking lots shall be minimized to the maximum extent practicable.  Winter de-icing sand and salt materials shall be stored in garages off site.  Immediately clean up any spillage on paved areas and dispose of the wastes properly.  Do not wash vehicles or equipment in a location where cleaning water, oil, fuel and grease can drain to the wetland resource areas. Emergency Spill Cleanup Plan 1. The owner of the facility shall have a designated person with overall responsibility for spill response cleanup. 2. In the event of a spill the following shall be notified: A. Yarmouth Fire Department .............................................................. (508) 398-2212 (For a gasoline or hazardous material spill) ....................................................... 911 B. Massachusetts Department of Environmental Protection Emergency Response ..................................................................... 1 (888) 304-1133 C. Yarmouth Board of Health .............................................. (508) 398-2231 ext. 1241 3. Cleanup of spills shall begin immediately. APPENDIX A Checklist for Stormwater Report DZ-1 -Plan Showing Pre-Development Drainage Areas DZ-2 -Plan Showing Post-Development Drainage Areas Soil Conditions-NRCS Hydro-CAD Report Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include: • The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report. • Applicant/Project Name • Project Address • Name of Firm and Registered Professional Engineer that prepared the Report • Long-Term Pollution Prevention Plan required by Standards 4-6 • Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 • Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report B.Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report. The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable (N.A.) and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer’s Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement (if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? New development Redevelopment Mix of New Development and Redevelopment Tarja L. McGrail, P.E. 12/07/2023 Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Standard 1: No New Untreated Discharges No new untreated discharges Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 2: Peak Rate Attenuation Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge Soil Analysis provided. Required Recharge Volume calculation provided. Required Recharge volume reduced through use of the LID site Design Credits. Sizing the infiltration, BMPs is based on the following method: Check the method used. Static Simple Dynamic Dynamic Field1 Runoff from all impervious areas at the site discharging to the infiltration BMP. Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: Site is comprised solely of C and D soils and/or bedrock at the land surface M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 Solid Waste Landfill pursuant to 310 CMR 19.000 Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. Calculations showing that the infiltration BMPs will drain in 72 hours are provided. Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included. 1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following: • Good housekeeping practices; • Provisions for storing materials and waste products inside or under cover; • Vehicle washing controls; • Requirements for routine inspections and maintenance of stormwater BMPs; • Spill prevention and response plans; • Provisions for maintenance of lawns, gardens, and other landscaped areas; • Requirements for storage and use of fertilizers, herbicides, and pesticides; • Pet waste management provisions; • Provisions for operation and management of septic systems; • Provisions for solid waste management; • Snow disposal and plowing plans relative to Wetland Resource Areas; • Winter Road Salt and/or Sand Use and Storage restrictions; • Street sweeping schedules; • Provisions for prevention of illicit discharges to the stormwater management system; • Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; • Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; • List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. Treatment BMPs subject to the 44% TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: is within the Zone II or Interim Wellhead Protection Area is near or to other critical areas is within soils with a rapid infiltration rate (greater than 2.4 inches per hour) involves runoff from land uses with higher potential pollutant loads. The Required Water Quality Volume is reduced through use of the LID site Design Credits. Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) The BMP is sized (and calculations provided) based on: The ½” or 1” Water Quality Volume or The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. The NPDES Multi-Sector General Permit does not cover the land use. LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. All exposure has been eliminated. All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. Critical areas and BMPs are identified in the Stormwater Report. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: Limited Project Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff Bike Path and/or Foot Path Redevelopment Project Redevelopment portion of mix of new and redevelopment. Certain standards are not fully met (Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: • Narrative; • Construction Period Operation and Maintenance Plan; • Names of Persons or Entity Responsible for Plan Compliance; • Construction Period Pollution Prevention Measures; • Erosion and Sedimentation Control Plan Drawings; • Detail drawings and specifications for erosion control BMPs, including sizing calculations; • Vegetation Planning; • Site Development Plan; • Construction Sequencing Plan; • Sequencing of Erosion and Sedimentation Controls; • Operation and Maintenance of Erosion and Sedimentation Controls; • Inspection Schedule; • Maintenance Schedule; • Inspection and Maintenance Log Form. A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. Stormwater Report Checklist • 04/01/08 Stormwater Report Checklist • Page 8 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. The project is not covered by a NPDES Construction General Permit. The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: Name of the stormwater management system owners; Party responsible for operation and maintenance; Schedule for implementation of routine and non-routine maintenance tasks; Plan showing the location of all stormwater BMPs maintenance access areas; Description and delineation of public safety features; Estimated operation and maintenance budget; and Operation and Maintenance Log Form. The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: A copy of the legal instrument (deed, homeowner’s association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; An Illicit Discharge Compliance Statement is attached; NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. © 2023 Microsoft Corporation © 2023 Maxar ©CNES (2023) Distribution Airbus DS VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV MILL CREEKVVVVVV FORMER LOCATION OF YANKEE VILLAGE MOTELAPPROX. AREA OF BUILDINGS, PAVED PARKING AREAS, AND POOL=38,000 ± S.F. IMPERVIOUS PAVEDPATIO & WALKWAY =1,861 ± S.F.VEGETATED AREA= 12,900 ± S.F.IMPERVIOUS PAVEDPARKING AREA = 7,015 ± S.F.VEGETATED AREA= 8,100 ± S.F.IMPERVIOUS PAVEDPARKING AREA = 6,481 ± S.F.IMPERVIOUS BRICKWALKWAY AREA = 1890± S.F.IMPERVIOUS BRICKPATIO AREA = 220± S.F.VEGETATED AREA= 24,000 ± S.F.Coastal Engineering Co., Inc. © 2023 PROJECT NO. OF SHEETSDRAWN BYDRAWING FILECHECKED BYDATEPROJECTSCALE SHEET TITLE SEALDATENO.REVISION BY G:\C23\C23015.01 - Town of Yarmouth - WFM\CAD\WIP\C23015-01-SW-IFP.dwg 12/5/2023 11:39 AM CHASE BROOK PARK RESTORATION TOWN OF YARMOUTH 261 & 275 ROUTE 28 WEST YARMOUTH, MA C23015.01PREDEVELOPMENT DRAINAGE AREASDZ-1AS NOTED12/7/2023C23015-01-SW-IFP.dwgTLMPRE-DEVELOPMENT LAND USE AREASSCALE: 1" = 30'YANKEE VILLAGE PARCEL(SEE SHEETS L-202 & L-302)CHASE BROOK PARCEL(SEE SHEETS L-201 & L-301)1 inch = 30 ft.301503090THIS DRAWING IS PREPARED FOR PERMITTING PURPOSES ONLYAND SHALL NOT BE USED FOR CONSTRUCTION.MILL CREEK PARCEL(SEE SHEETS L-203 & L-303) © 2023 Microsoft Corporation © 2023 Maxar ©CNES (2023) Distribution Airbus DS TMOSW MXMMMMMWVMMPTMVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV VVVVVV VVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVVV MILL CREEKVVVVVV IMPERVIOUS PAVED PARKING(NO CHANGE),AREA = 7,015 ± S.F.PROPOSEDAGGREGATE WALKWAYAREA = 3,540 ± S.F.PROPOSEDBRIDGE ABUTMENT= 24 ± S.F.PROPOSEDBRIDGE ABUTMENT= 24 ± S.F.PROPOSEDAGGREGATE WALKWAYAREA = 3,820 ± S.F.PROPOSEDAGGREGATE WALKWAYAREA =2,480 ± S.F.IMPERVIOUS PAVED PARKING(NO CHANGE)AREA = 6,481 ± S.F.PROPOSEDVEGETATEDAREA =24,000 ± S.F.PROPOSEDVEGETATEDAREA =24,000 ± S.F.PROPOSEDVEGETATEDAREA =12,900 ± S.F.Coastal Engineering Co., Inc. © 2023 PROJECT NO. OF SHEETSDRAWN BYDRAWING FILECHECKED BYDATEPROJECTSCALE SHEET TITLE SEALDATENO.REVISION BY G:\C23\C23015.01 - Town of Yarmouth - WFM\CAD\WIP\C23015-01-SW-IFP.dwg 12/5/2023 12:40 PM CHASE BROOK PARK RESTORATION TOWN OF YARMOUTH 261 & 275 ROUTE 28 WEST YARMOUTH, MA C23015.01POST DEVELOPMENT DRAINAGE AREASDZ-2AS NOTED12/7/2023C23015-01-SW-IFP.dwgTLMPOST DEVELOPMENT LAND USE AREASSCALE: 1" = 30'YANKEE VILLAGE PARCEL(SEE SHEETS L-202 & L-302)CHASE BROOK PARCEL(SEE SHEETS L-201 & L-301)1 inch = 30 ft.301503090THIS DRAWING IS PREPARED FOR PERMITTING PURPOSES ONLYAND SHALL NOT BE USED FOR CONSTRUCTION.MILL CREEK PARCEL(SEE SHEETS L-203 & L-303) Soil Map—Barnstable County, Massachusetts (Chase Brook Park, Yankee Village, Mill Creek Park) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/21/2023 Page 1 of 34611860461192046119804612040461210046121604612220461186046119204611980461204046121004612160395370395430395490395550395610395670395730395790395850395910 395370 395430 395490 395550 395610 395670 395730 395790 395850 395910 41° 39' 17'' N 70° 15' 24'' W41° 39' 17'' N70° 14' 59'' W41° 39' 5'' N 70° 15' 24'' W41° 39' 5'' N 70° 14' 59'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 19N WGS84 0 100 200 400 600 Feet 0 35 70 140 210 Meters Map Scale: 1:2,580 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:25,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Barnstable County, Massachusetts Survey Area Data: Version 20, Sep 12, 2023 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 10, 2022—Jun 30, 2022 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—Barnstable County, Massachusetts (Chase Brook Park, Yankee Village, Mill Creek Park) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/21/2023 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 54A Freetown and Swansea mucks, coastal lowland, 0 to 1 percent slopes 0.6 2.4% 55A Freetown coarse sand, 0 to 3 percent slopes, sanded surface 0.0 0.2% 66A Ipswich - Pawcatuck - Matunuck complex, 0 to 2 percent slopes, very frequently flooded 2.6 10.6% 252A Carver coarse sand, 0 to 3 percent slopes 4.7 19.3% 252B Carver coarse sand, 3 to 8 percent slopes 12.7 52.6% 607 Water, saline 3.6 15.0% Totals for Area of Interest 24.2 100.0% Soil Map—Barnstable County, Massachusetts Chase Brook Park, Yankee Village, Mill Creek Park Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 11/21/2023 Page 3 of 3 132S Chase Brook Park Develop- pre 133S Yankee Village - Pre Demo 137S Mill Creek Park Develop- pre Routing Diagram for C23015_Pre vs post report Prepared by {enter your company name here}, Printed 12/5/2023 HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 2HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2 Type III 24-hr Default 24.00 1 3.60 2 2 10 Type III 24-hr Default 24.00 1 4.80 2 C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 3HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Area Listing (selected nodes) Area (acres) CN Description (subcatchment-numbers) 0.310 98 Paved parking, HSG A (132S, 137S) 0.964 98 Unconnected pavement, HSG A (132S, 133S, 137S) 1.033 43 Woods/grass comb., Fair, HSG A (132S, 133S, 137S) 2.307 73 TOTAL AREA C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 4HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Soil Listing (selected nodes) Area (acres) Soil Group Subcatchment Numbers 2.307 HSG A 132S, 133S, 137S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 2.307 TOTAL AREA C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 5HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Ground Covers (selected nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.310 0.000 0.000 0.000 0.000 0.310 Paved parking 132S, 137S 0.964 0.000 0.000 0.000 0.000 0.964 Unconnected pavement 132S, 133S, 137S 1.033 0.000 0.000 0.000 0.000 1.033 Woods/grass comb., Fair 132S, 133S, 137S 2.307 0.000 0.000 0.000 0.000 2.307 TOTAL AREA Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 6HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Time span=0.00-20.00 hrs, dt=0.01 hrs, 2001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=21,776 sf 40.76% Impervious Runoff Depth>0.72"Subcatchment 132S: Chase Brook Park Tc=10.0 min CN=65 Runoff=0.35 cfs 0.030 af Runoff Area=46,100 sf 82.43% Impervious Runoff Depth>2.21"Subcatchment 133S: Yankee Village - Pre Tc=10.0 min CN=88 Runoff=2.54 cfs 0.195 af Runoff Area=32,599 sf 26.38% Impervious Runoff Depth>0.36"Subcatchment 137S: Mill Creek Park Tc=10.0 min UI Adjusted CN=56 Runoff=0.16 cfs 0.022 af Total Runoff Area = 2.307 ac Runoff Volume = 0.247 af Average Runoff Depth = 1.29" 44.79% Pervious = 1.033 ac 55.21% Impervious = 1.274 ac Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 7HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 132S: Chase Brook Park Develop- pre Runoff = 0.35 cfs @ 12.16 hrs, Volume= 0.030 af, Depth> 0.72" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 1,311 98 Unconnected pavement, HSG A 12,900 43 Woods/grass comb., Fair, HSG A 550 98 Unconnected pavement, HSG A 7,015 98 Paved parking, HSG A 21,776 65 Weighted Average 12,900 59.24% Pervious Area 8,876 40.76% Impervious Area 1,861 20.97% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 132S: Chase Brook Park Develop- pre Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=21,776 sf Runoff Volume=0.030 af Runoff Depth>0.72" Tc=10.0 min CN=65 0.35 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 8HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 133S: Yankee Village - Pre Demo Runoff = 2.54 cfs @ 12.14 hrs, Volume= 0.195 af, Depth> 2.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 38,000 98 Unconnected pavement, HSG A 8,100 43 Woods/grass comb., Fair, HSG A 46,100 88 Weighted Average 8,100 17.57% Pervious Area 38,000 82.43% Impervious Area 38,000 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 133S: Yankee Village - Pre Demo Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=46,100 sf Runoff Volume=0.195 af Runoff Depth>2.21" Tc=10.0 min CN=88 2.54 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 9HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 137S: Mill Creek Park Develop- pre Runoff = 0.16 cfs @ 12.23 hrs, Volume= 0.022 af, Depth> 0.36" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Adj Description 1,890 98 Unconnected pavement, HSG A 24,000 43 Woods/grass comb., Fair, HSG A 228 98 Unconnected pavement, HSG A 6,481 98 Paved parking, HSG A 32,599 58 56 Weighted Average, UI Adjusted 24,000 73.62% Pervious Area 8,599 26.38% Impervious Area 2,118 24.63% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 137S: Mill Creek Park Develop- pre Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=32,599 sf Runoff Volume=0.022 af Runoff Depth>0.36" Tc=10.0 min UI Adjusted CN=56 0.16 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 10HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Time span=0.00-20.00 hrs, dt=0.01 hrs, 2001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=21,776 sf 40.76% Impervious Runoff Depth>1.38"Subcatchment 132S: Chase Brook Park Tc=10.0 min CN=65 Runoff=0.73 cfs 0.058 af Runoff Area=46,100 sf 82.43% Impervious Runoff Depth>3.28"Subcatchment 133S: Yankee Village - Pre Tc=10.0 min CN=88 Runoff=3.70 cfs 0.289 af Runoff Area=32,599 sf 26.38% Impervious Runoff Depth>0.84"Subcatchment 137S: Mill Creek Park Tc=10.0 min UI Adjusted CN=56 Runoff=0.57 cfs 0.052 af Total Runoff Area = 2.307 ac Runoff Volume = 0.399 af Average Runoff Depth = 2.07" 44.79% Pervious = 1.033 ac 55.21% Impervious = 1.274 ac Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 11HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 132S: Chase Brook Park Develop- pre Runoff = 0.73 cfs @ 12.15 hrs, Volume= 0.058 af, Depth> 1.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 1,311 98 Unconnected pavement, HSG A 12,900 43 Woods/grass comb., Fair, HSG A 550 98 Unconnected pavement, HSG A 7,015 98 Paved parking, HSG A 21,776 65 Weighted Average 12,900 59.24% Pervious Area 8,876 40.76% Impervious Area 1,861 20.97% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 132S: Chase Brook Park Develop- pre Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=21,776 sf Runoff Volume=0.058 af Runoff Depth>1.38" Tc=10.0 min CN=65 0.73 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 12HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 133S: Yankee Village - Pre Demo Runoff = 3.70 cfs @ 12.14 hrs, Volume= 0.289 af, Depth> 3.28" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 38,000 98 Unconnected pavement, HSG A 8,100 43 Woods/grass comb., Fair, HSG A 46,100 88 Weighted Average 8,100 17.57% Pervious Area 38,000 82.43% Impervious Area 38,000 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 133S: Yankee Village - Pre Demo Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)4 3 2 1 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=46,100 sf Runoff Volume=0.289 af Runoff Depth>3.28" Tc=10.0 min CN=88 3.70 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 13HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 137S: Mill Creek Park Develop- pre Runoff = 0.57 cfs @ 12.17 hrs, Volume= 0.052 af, Depth> 0.84" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Adj Description 1,890 98 Unconnected pavement, HSG A 24,000 43 Woods/grass comb., Fair, HSG A 228 98 Unconnected pavement, HSG A 6,481 98 Paved parking, HSG A 32,599 58 56 Weighted Average, UI Adjusted 24,000 73.62% Pervious Area 8,599 26.38% Impervious Area 2,118 24.63% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 137S: Mill Creek Park Develop- pre Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=32,599 sf Runoff Volume=0.052 af Runoff Depth>0.84" Tc=10.0 min UI Adjusted CN=56 0.57 cfs 130S Chase Brook Park Develop- post 131S Chase Brook Park Post- Bridge Abutment 134S Yankee Village - Post 135S Yankee Village Post- Bridge Abutment 138S Mill Creek Park Develop- post Routing Diagram for C23015_Pre vs post report Prepared by {enter your company name here}, Printed 12/5/2023 HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 2HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2 Type III 24-hr Default 24.00 1 3.60 2 2 10 Type III 24-hr Default 24.00 1 4.80 2 C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 3HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Area Listing (selected nodes) Area (acres) CN Description (subcatchment-numbers) 0.002 98 Concrete Abutment (130S, 131S, 135S) 0.226 76 Gravel roads, HSG A (130S, 134S, 138S) 1.398 30 Meadow, non-grazed, HSG A (130S, 134S, 138S) 0.310 98 Paved parking, HSG A (130S, 138S) 1.935 46 TOTAL AREA C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 4HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Soil Listing (selected nodes) Area (acres) Soil Group Subcatchment Numbers 1.934 HSG A 130S, 134S, 138S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.002 Other 130S, 131S, 135S 1.935 TOTAL AREA C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 5HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Ground Covers (selected nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.000 0.000 0.000 0.000 0.002 0.002 Concrete Abutment 130S, 131S, 135S 0.226 0.000 0.000 0.000 0.000 0.226 Gravel roads 130S, 134S, 138S 1.398 0.000 0.000 0.000 0.000 1.398 Meadow, non-grazed 130S, 134S, 138S 0.310 0.000 0.000 0.000 0.000 0.310 Paved parking 130S, 138S 1.934 0.000 0.000 0.000 0.002 1.935 TOTAL AREA Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 6HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Time span=0.00-20.00 hrs, dt=0.01 hrs, 2001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=23,479 sf 29.98% Impervious Runoff Depth>0.39"Subcatchment 130S: Chase Brook Park Tc=10.0 min CN=57 Runoff=0.14 cfs 0.018 af Runoff Area=24 sf 100.00% Impervious Runoff Depth>3.20"Subcatchment 131S: Chase Brook Park Post- Tc=10.0 min CN=98 Runoff=0.00 cfs 0.000 af Runoff Area=27,820 sf 0.00% Impervious Runoff Depth=0.00"Subcatchment 134S: Yankee Village - Post Tc=10.0 min CN=36 Runoff=0.00 cfs 0.000 af Runoff Area=24 sf 100.00% Impervious Runoff Depth>3.20"Subcatchment 135S: Yankee Village Post- Tc=10.0 min CN=98 Runoff=0.00 cfs 0.000 af Runoff Area=32,961 sf 19.66% Impervious Runoff Depth>0.11"Subcatchment 138S: Mill Creek Park Tc=10.0 min CN=47 Runoff=0.02 cfs 0.007 af Total Runoff Area = 1.935 ac Runoff Volume = 0.025 af Average Runoff Depth = 0.16" 83.91% Pervious = 1.624 ac 16.09% Impervious = 0.311 ac Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 7HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 130S: Chase Brook Park Develop- post Runoff = 0.14 cfs @ 12.21 hrs, Volume= 0.018 af, Depth> 0.39" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 3,540 76 Gravel roads, HSG A * 24 98 Concrete Abutment 12,900 30 Meadow, non-grazed, HSG A 7,015 98 Paved parking, HSG A 23,479 57 Weighted Average 16,440 70.02% Pervious Area 7,039 29.98% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 130S: Chase Brook Park Develop- post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=23,479 sf Runoff Volume=0.018 af Runoff Depth>0.39" Tc=10.0 min CN=57 0.14 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 8HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 131S: Chase Brook Park Post- Bridge Abutment Runoff = 0.00 cfs @ 12.13 hrs, Volume= 0.000 af, Depth> 3.20" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 0 76 Gravel roads, HSG A * 24 98 Concrete Abutment 0 30 Meadow, non-grazed, HSG A 24 98 Weighted Average 24 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, direct 6.0 0 Total, Increased to minimum Tc = 10.0 min Subcatchment 131S: Chase Brook Park Post- Bridge Abutment Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=24 sf Runoff Volume=0.000 af Runoff Depth>3.20" Tc=10.0 min CN=98 0.00 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 9HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 134S: Yankee Village - Post [45] Hint: Runoff=Zero Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 0 98 Unconnected pavement, HSG A 24,000 30 Meadow, non-grazed, HSG A 3,820 76 Gravel roads, HSG A 27,820 36 Weighted Average 27,820 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 134S: Yankee Village - Post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=27,820 sf Runoff Volume=0.000 af Runoff Depth=0.00" Tc=10.0 min CN=36 0.00 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 10HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 135S: Yankee Village Post- Bridge Abutment Runoff = 0.00 cfs @ 12.13 hrs, Volume= 0.000 af, Depth> 3.20" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 0 76 Gravel roads, HSG A * 24 98 Concrete Abutment 0 30 Meadow, non-grazed, HSG A 24 98 Weighted Average 24 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, direct 6.0 0 Total, Increased to minimum Tc = 10.0 min Subcatchment 135S: Yankee Village Post- Bridge Abutment Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=24 sf Runoff Volume=0.000 af Runoff Depth>3.20" Tc=10.0 min CN=98 0.00 cfs Type III 24-hr 2 Rainfall=3.60"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 11HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 138S: Mill Creek Park Develop- post Runoff = 0.02 cfs @ 12.54 hrs, Volume= 0.007 af, Depth> 0.11" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 2 Rainfall=3.60" Area (sf) CN Description 2,480 76 Gravel roads, HSG A 24,000 30 Meadow, non-grazed, HSG A 6,481 98 Paved parking, HSG A 32,961 47 Weighted Average 26,480 80.34% Pervious Area 6,481 19.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 138S: Mill Creek Park Develop- post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.02 0.019 0.018 0.017 0.016 0.015 0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 2 Rainfall=3.60" Runoff Area=32,961 sf Runoff Volume=0.007 af Runoff Depth>0.11" Tc=10.0 min CN=47 0.02 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 12HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Time span=0.00-20.00 hrs, dt=0.01 hrs, 2001 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=23,479 sf 29.98% Impervious Runoff Depth>0.89"Subcatchment 130S: Chase Brook Park Tc=10.0 min CN=57 Runoff=0.45 cfs 0.040 af Runoff Area=24 sf 100.00% Impervious Runoff Depth>4.35"Subcatchment 131S: Chase Brook Park Post- Tc=10.0 min CN=98 Runoff=0.00 cfs 0.000 af Runoff Area=27,820 sf 0.00% Impervious Runoff Depth>0.06"Subcatchment 134S: Yankee Village - Post Tc=10.0 min CN=36 Runoff=0.01 cfs 0.003 af Runoff Area=24 sf 100.00% Impervious Runoff Depth>4.35"Subcatchment 135S: Yankee Village Post- Tc=10.0 min CN=98 Runoff=0.00 cfs 0.000 af Runoff Area=32,961 sf 19.66% Impervious Runoff Depth>0.40"Subcatchment 138S: Mill Creek Park Tc=10.0 min CN=47 Runoff=0.16 cfs 0.025 af Total Runoff Area = 1.935 ac Runoff Volume = 0.069 af Average Runoff Depth = 0.42" 83.91% Pervious = 1.624 ac 16.09% Impervious = 0.311 ac Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 13HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 130S: Chase Brook Park Develop- post Runoff = 0.45 cfs @ 12.16 hrs, Volume= 0.040 af, Depth> 0.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 3,540 76 Gravel roads, HSG A * 24 98 Concrete Abutment 12,900 30 Meadow, non-grazed, HSG A 7,015 98 Paved parking, HSG A 23,479 57 Weighted Average 16,440 70.02% Pervious Area 7,039 29.98% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 130S: Chase Brook Park Develop- post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.5 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=23,479 sf Runoff Volume=0.040 af Runoff Depth>0.89" Tc=10.0 min CN=57 0.45 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 14HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 131S: Chase Brook Park Post- Bridge Abutment Runoff = 0.00 cfs @ 12.13 hrs, Volume= 0.000 af, Depth> 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 0 76 Gravel roads, HSG A * 24 98 Concrete Abutment 0 30 Meadow, non-grazed, HSG A 24 98 Weighted Average 24 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, direct 6.0 0 Total, Increased to minimum Tc = 10.0 min Subcatchment 131S: Chase Brook Park Post- Bridge Abutment Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.003 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=24 sf Runoff Volume=0.000 af Runoff Depth>4.35" Tc=10.0 min CN=98 0.00 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 15HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 134S: Yankee Village - Post Runoff = 0.01 cfs @ 15.19 hrs, Volume= 0.003 af, Depth> 0.06" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 0 98 Unconnected pavement, HSG A 24,000 30 Meadow, non-grazed, HSG A 3,820 76 Gravel roads, HSG A 27,820 36 Weighted Average 27,820 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 134S: Yankee Village - Post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.007 0.007 0.006 0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=27,820 sf Runoff Volume=0.003 af Runoff Depth>0.06" Tc=10.0 min CN=36 0.01 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 16HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 135S: Yankee Village Post- Bridge Abutment Runoff = 0.00 cfs @ 12.13 hrs, Volume= 0.000 af, Depth> 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 0 76 Gravel roads, HSG A * 24 98 Concrete Abutment 0 30 Meadow, non-grazed, HSG A 24 98 Weighted Average 24 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, direct 6.0 0 Total, Increased to minimum Tc = 10.0 min Subcatchment 135S: Yankee Village Post- Bridge Abutment Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.003 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=24 sf Runoff Volume=0.000 af Runoff Depth>4.35" Tc=10.0 min CN=98 0.00 cfs Type III 24-hr 10 Rainfall=4.80"C23015_Pre vs post report Printed 12/5/2023Prepared by {enter your company name here} Page 17HydroCAD® 10.10-5a s/n 04240 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 138S: Mill Creek Park Develop- post Runoff = 0.16 cfs @ 12.34 hrs, Volume= 0.025 af, Depth> 0.40" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-20.00 hrs, dt= 0.01 hrs Type III 24-hr 10 Rainfall=4.80" Area (sf) CN Description 2,480 76 Gravel roads, HSG A 24,000 30 Meadow, non-grazed, HSG A 6,481 98 Paved parking, HSG A 32,961 47 Weighted Average 26,480 80.34% Pervious Area 6,481 19.66% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, direct Subcatchment 138S: Mill Creek Park Develop- post Runoff Hydrograph Time (hours) 20191817161514131211109876543210Flow (cfs)0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 10 Rainfall=4.80" Runoff Area=32,961 sf Runoff Volume=0.025 af Runoff Depth>0.40" Tc=10.0 min CN=47 0.16 cfs