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307Main_Definitive Stormwater STORMWATER MANAGEMENT REPORT 307 MAIN STREET 307 Main Street Hyannis, Massachusetts April 11, 2024 344700RP004A.docx Prepared by: Beals and Thomas, Inc. 144 Turnpike Road Southborough, MA 01772 Prepared for: WinnDevelopment 1 Washington Mall, Suite 500 Boston, MA 02108 307 Main Street Stormwater Management Report Hyannis, Massachusetts Table of Contents i TABLE OF CONTENTS 1.0 INTRODUCTION .................................................................................................................. 1 2.0 PRE-DEVELOPMENT CONDITIONS ..................................................................................... 2 2.1 SITE CONDITIONS ...................................................................................................................................... 2 2.1.1 Critical Areas ................................................................................................................................. 2 2.1.2 Total Maximum Daily Loads (TMDL) ........................................................................................... 2 2.2 SOIL DESCRIPTION .................................................................................................................................... 3 2.3 HYDROLOGIC ANALYSIS............................................................................................................................. 3 3.0 POST-DEVELOPMENT CONDITIONS .................................................................................. 4 3.1 DESIGN STRATEGY..................................................................................................................................... 4 3.2 HYDROLOGIC ANALYSIS............................................................................................................................. 4 3.3 STORMWATER MANAGEMENT CONTROLS SIZING ....................................................................................... 5 3.4 HYDRAULIC CALCULATIONS ....................................................................................................................... 5 3.5 COMPLIANCE WITH DEP STORMWATER MANAGEMENT STANDARDS ........................................................... 5 3.6 DEP’S CHECKLIST FOR A STORMWATER REPORT ......................................................................................... 9 LIST OF ATTACHMENTS ATTACHMENT 1: SOIL DATA ATTACHMENT 2: PRE-DEVELOPMENT HYDROLOGIC ANALYSIS ATTACHMENT 3: POST-DEVELOPMENT HYDROLOGIC ANALYSIS ATTACHMENT 4: HYDRAULIC CALCULATIONS ATTACHMENT 5: TSS REMOVAL, WATER QUALITY, AND RECHARGE CALCULATIONS ATTACHMENT 6: SITE OWNER’S MANUAL ATTACHMENT 7: DRAFT STORMWATER POLLUTION PREVENTION PLAN 307 Main Street Stormwater Management Report Hyannis, Massachusetts 1 1.0 INTRODUCTION The proposed project includes a stormwater management system designed to mitigate potential impacts the proposed project could have on the existing watershed. Stormwater controls have been proposed to control peak runoff rates, provide water quality, promote groundwater recharge and sediment removal. The proposed system has been designed to comply with:  The 2008 Massachusetts Department of Environmental Protection (DEP) Stormwater Management Handbook,  Town of Barnstable Subdivision Rules and Regulations (the Regulations)  Town of Barnstable Zoning Ordinance as amended through November 2022 (the Ordinance), which requires projects to infiltrate the 25-year storm on site. The pre- and post-development hydrologic conditions were modeled using HydroCADTM version 10.00 to demonstrate that post-development stormwater runoff rates and volumes will be less than or equal to the pre-development rates and volumes. The following tables summarize the peak runoff rates and volumes for the pre- and post-development conditions. Table 1: Pre- & Post-development Peak Runoff Rate Comparison, units are in cubic feet per second (cfs). Storm Event Design Point 1: Main Street Design Point 2: On-Site System Pre Post Pre Post 2-Year 0.16 0.15 3.80 0.00 10-Year 0.65 0.37 6.19 0.00 25-Year 1.11 0.56 8.03 0.00 100-Year 2.17 0.97 11.70 0.00 Table 2: Pre- & Post-development Runoff Volume Comparison, units are in acre-feet. Storm Event Design Point 1: Main Street Design Point 2: On-Site System Pre Post Pre Post 2-Year 0.02 0.01 0.26 0.00 10-Year 0.05 0.03 0.44 0.00 25-Year 0.08 0.04 0.58 0.00 100-Year 0.15 0.07 0.87 0.00 307 Main Street Stormwater Management Report Hyannis, Massachusetts 2 2.0 PRE-DEVELOPMENT CONDITIONS 2.1 Site Conditions The Property is currently developed and mainly covered by either building or pavement. It contains of a two-story commercial building that is currently unoccupied, a parking lot, and limited landscaped areas. The stormwater controls on site are currently in disrepair. Several catch basins and leaching pits were found to be clogged. Based upon field investigations it appears that several on-site leaching pits previous infiltrated runoff from the parking lot, building and driveways on Old Colony Road. In the event these leaching pits reached capacity, the stormwater would sheet towards Old Colony Road and the abutting property to the south. The portions of the site along Main Street and Old Colony Road sheet flow directly into the municipal system. Catch basins on site are currently daisy chained together and do not provide for water quality treatment. Field investigations found no evidence of water quality treatment units or other methods of stormwater treatment. The design points within the hydrologic analysis represent the flow that would reach the Main Street (Design Point 1) and the internal drainage system (Design Point 2). 2.1.1 Critical Areas Critical Areas as defined by Standard 6 of the 2008 MassDEP Stormwater Management Handbook are areas where high levels of stormwater treatment is required; typically the first inch of runoff is treated using specific best management practices (BMPs) and pre-treatment methods. Specific source control and pollution prevention measures are also required. The site does not contain, nor is it tributary to any Critical Areas. 2.1.2 Total Maximum Daily Loads (TMDL) A TMDL is the greatest amount of a pollutant that a waterbody can accept and still meet water quality standards for protecting public health and maintaining the designated beneficial uses of those waters for drinking, swimming, recreation, and fishing. A TMDL is implemented by specifying how much of that pollutant can come from point, nonpoint, and natural sources. MassDEP has issued a TMDL for the Cape Cod Watershed for Pathogens and further has issued a TMDL for Lewis Bay and Halls Creek for Total Nitrogen. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 3 2.2 Soil Description The Natural Resources Conservation Service (NRCS) lists the on-site soils as Urban land. Generally, this soil is located in areas of excavation and fill. A geotechnical study was performed by McPhail Associates. Soil textural analysis and sieve testing classified the soils on site sand. For the purposes of our analysis, we have assumed the soils to be NRCS hydrologic soil class A. 2.3 Hydrologic Analysis Sub-catchment areas were delineated based on existing runoff patterns and topographic information. This information is shown on the Pre-Development Conditions Hydrologic Areas Map included in Attachment 2. Summaries of each area with respect to Curve Number and Time of Concentration calculations can be found in the model results also in Attachment 2. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 4 3.0 POST-DEVELOPMENT CONDITIONS 3.1 Design Strategy During the design phase of the site layout, consideration was given to conserving environmentally sensitive features and minimizing impact on the existing hydrology. To achieve this, extensive grading was avoided and the site was designed to match the existing terrain where feasible. Minimizing earthwork helps to maintain the existing drainage patterns to the maximum extent practicable under post- development conditions. Through careful site planning the proposed impervious surfaces have been minimized, reducing the impact the project may have on the existing watershed. This minimization of impervious surfaces was achieved without compromising compliance to local bylaw requirements. A stormwater management system has been designed to infiltrate up to the 25-year storm in compliance with the local regulations. In addition, it will provide groundwater recharge and water quality treatment. Proprietary water quality units have been incorporated to ensure 44% total suspended solids are removed from roadway runoff prior to discharging to the infiltration systems. In addition to groundwater recharge and peak runoff mitigation, the recharge systems also provide nutrient removal. A stormwater management system has been designed to provide treatment for stormwater runoff associated with the proposed impervious surfaces on site. All stormwater BMPs were designed to treat a minimum of the first 1.0 inch of runoff generated by the on-site impervious areas. Proprietary stormwater treatment systems were designed to treat the runoff rate associated with the water quality volume in accordance with the requirements of the DEP Stormwater Handbook. Stormwater BMP sizing worksheets and water quality sizing calculations are included in Attachment 5 of this report. 3.2 Hydrologic Analysis The established design points used in the pre-development conditions analysis were used in the post-development analysis for direct comparison. The tributary areas and flow paths were modified to reflect post-development conditions. See Attachment 3 for the Post- Development Conditions Hydrologic Areas Map. Summaries of each area with respect to Curve Number and Time of Concentration calculations can be found in the model results in Attachment 3. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 5 3.3 Stormwater Management Controls Sizing Infiltration Chamber The proposed stormwater infiltration system consists of StormTech MC-7200 chambers with a stone base. The whole system has been designed to handle up to the 100-year storm. The infiltration system was sized using the Static Method, as described in Chapter 3 of the Massachusetts Stormwater Handbook, using Rawl’s exfiltration rates of 2.41 inches per hour or 8.27 inches per hour based on the recommendations from the geotechnical engineer. The system has been designed to meet the required recharge volume, and will fully dewater within 72 hours. 3.4 Hydraulic Calculations In compliance with Barnstable requirements, the proposed storm drain system was analyzed based on the 50-year storm event using the Rational Formula. A watershed map and detailed hydraulic analysis are provided in Attachment 4. 3.5 Compliance with DEP Stormwater Management Standards The proposed stormwater management system was designed in compliance with the ten (10) DEP Stormwater Management Standards. The following summary provides key information related to the proposed stormwater management system, its design elements, and mitigation measures for potential impacts. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 6 STANDARD 1: No new stormwater conveyance (e.g. outfalls) may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth. There are no wetlands or waters on or near the site; therefore, this standard does not apply. STANDARD 2: Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates. The stormwater management design will control post-development peak discharge rates for the 2-, 10-, and 100-year, 24-hour storms so as to maintain pre-development peak discharge rates. Refer to Section 1.0 Introduction for a summary of the peak runoff rates. STANDARD 3: Loss of annual recharge to groundwater shall be eliminated or minimized through the use of environmentally sensitive site design, low impact development techniques, stormwater management practices and good operation and maintenance. At a minimum, the annual recharge from the post-development site shall approximate the annual recharge from pre- development conditions based on soil types. This Standard is met when the stormwater management system is designed to infiltrate the required recharge volume as determined in accordance with the Massachusetts Stormwater Handbook. The stormwater management system includes subsurface infiltration systems that will effectively recharge groundwater on-site. Infiltration BMPs were sized using the static method based on the required recharge volume for the post-development site. As a result, annual recharge from the post-development site will approximate the annual recharge from the site under pre-development conditions. See Attachment 5 for stormwater BMP design worksheets and Groundwater Recharge Calculation. STANDARD 4: Stormwater management systems shall be designed to remove 80% of the average annual post-construction load of Total Suspended Solids (TSS). The proposed project will meet the water quality requirements of Standard 4 using several on-site treatment trains that achieve 80% TSS removal. Refer to Attachment 5 for the TSS removal worksheets. Structural BMPs designed for water quality treatment, including the deep sump hooded catch basins, and proprietary water quality treatment systems, were sized to capture and treat the flow rate associated with the first 1.0-inch of runoff from proposed impervious surfaces. All proposed stormwater management BMPs will be operated and maintained to ensure continued water quality treatment of runoff. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 7 The Site Owner’s Manual complies with the Long-Term Pollution Prevention Plan (Standard 4) and the Long-Term Operation and Maintenance Plan (Standard 9) requirements of the 2008 Massachusetts Department of Environmental Protection (MassDEP) Stormwater Management Standards. The Manual outlines source control and pollution prevention measures and maintenance requirements of stormwater best management practices (BMPs) associated with the proposed development. STANDARD 5: For land uses with higher potential pollutant loads (LUHPPLs), source control and pollution prevention shall be implemented in accordance with the Massachusetts Stormwater Handbook to eliminate or reduce the discharge of stormwater runoff from such land uses to the maximum extent practicable. The Project is not associated with stormwater discharges from land uses with higher potential pollutant loads. STANDARD 6: Stormwater discharges to critical areas must utilize certain stormwater management BMPs approved for critical areas. Critical areas are Outstanding Resource Waters, shellfish beds, swimming beaches, coldwater fisheries and recharge areas for public water supplies. There are no stormwater discharges to critical areas associated with this project. STANDARD 7: Redevelopment of previously developed sites must meet the Stormwater Management Standards to the maximum extent practicable. However, if it is not practicable to meet all the Standards, new (retrofitted or expanded) stormwater management systems must be designed to improve existing conditions. The proposed project qualifies as a redevelopment project. However, it fully complies with all standards of the Stormwater Management Handbook. STANDARD 8: A plan to control construction-related impacts during erosion, sedimentation and other pollutant sources during construction and land disturbance activities (construction period erosion, sedimentation, and pollution prevention plan) shall be developed and implemented. A Stormwater Pollution Prevention Plan (SWPPP) has been developed to comply with Section 3 of the NPDES Construction General Permit for Stormwater Discharges; therefore, the requirements of Standard 8 are fulfilled. 307 Main Street Stormwater Management Report Hyannis, Massachusetts 8 STANDARD 9: A Long-Term Operation and Maintenance (O&M) Plan shall be developed and implemented to ensure that stormwater management systems function as designed. The Site Owner’s Manual complies with the Long-Term Pollution Prevention Plan (Standard 4) and the Long-Term Operation and Maintenance Plan (Standard 9) requirements of the 2008 Massachusetts Department of Environmental Protection (MassDEP) Stormwater Management Standards. The Manual outlines source control and pollution prevention measures and maintenance requirements of the stormwater best management practices (BMPs) associated with the proposed development. STANDARD 10: All illicit discharges to the stormwater management system are prohibited. There will be no illicit discharges to the proposed stormwater management system associated with the proposed project. An Illicit Discharge Compliance Statement will be provided prior to the discharge of any stormwater to any post-construction BMPs. swcheck.doc • 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. swcheck.doc • 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 swcheck.doc • 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. swcheck.doc • 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. swcheck.doc • 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. swcheck.doc • 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. swcheck.doc • 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. swcheck.doc • 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. Attachment 1 Soil Data Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/15/2023 Page 1 of 4461150046117004611900461210046123004612500461270046113004611500461170046119004612100461230046125004612700392300392500392700392900393100393300393500393700393900394100394300394500 392300 392500 392700 392900 393100 393300 393500 393700 393900 394100 394300 394500 41° 39' 34'' N 70° 17' 38'' W41° 39' 34'' N70° 16' 0'' W41° 38' 46'' N 70° 17' 38'' W41° 38' 46'' N 70° 16' 0'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 19N WGS84 0 500 1000 2000 3000 Feet 0 150 300 600 900 Meters Map Scale: 1:10,400 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 Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available 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 19, Sep 9, 2022 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. Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/15/2023 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 55A Freetown coarse sand, 0 to 3 percent slopes, sanded surface B/D 13.0 2.4% 66A Ipswich - Pawcatuck - Matunuck complex, 0 to 2 percent slopes, very frequently flooded A/D 0.6 0.1% 252B Carver coarse sand, 3 to 8 percent slopes A 71.3 13.0% 602 Urban land 420.6 76.9% 607 Water, saline 29.1 5.3% 610 Beaches, sand 0.0 0.0% 665 Udipsamments, smoothed 12.2 2.2% Totals for Area of Interest 546.8 100.0% Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/15/2023 Page 3 of 4 Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/15/2023 Page 4 of 4 Barnstable County, Massachusetts 602—Urban land Map Unit Setting National map unit symbol: 98s7 Frost-free period: 120 to 220 days Farmland classification: Not prime farmland Map Unit Composition Urban land:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Setting Parent material:Excavated and filled land Minor Components Udipsamments Percent of map unit:15 percent Hydric soil rating: Unranked Data Source Information Soil Survey Area: Barnstable County, Massachusetts Survey Area Data: Version 19, Sep 9, 2022 Map Unit Description: Urban land---Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/15/2023 Page 1 of 1 FOUNDATION ENGINEERING REPORT 307 MAIN STREET HYANNIS, MASSACHUSETTS AUGUST 22, 2023 Prepared For: Winn Development One Washington Mall, Suite 500 Boston, MA 02108 PROJECT NO. 7682.2.T1 2269 Massachusetts Avenue Cambridge, MA 02140 www.mcphailgeo.com (617) 868-1420 August 22, 2023 GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERS 2269 Massachusetts Avenue Cambridge, Massachusetts 02140 (617) 868-1420 Winn Development One Washington Mall, Suite 500 Boston, MA 02108 Attention: Ramie Schneider Reference: 307 Main Street; Hyannis, Massachusetts Foundation Engineering Report – Executive Summary Enclosed is our Foundation Engineering Report for the above-referenced project. The following is an executive summary of the report. The proposed redevelopment of the subject site is understood to include the demolition of the existing building and the construction of a new four (4)-story irregularly shaped multi- unit residential building. The lowest level slab of the proposed building is understood to be located at approximate Elevation +29.5 which will be lower than the existing grade along Main Street. It is recommended that the proposed structure be founded on conventional footing foundations bearing directly on the undisturbed, natural glacial outwash deposit or on compacted structural fill or lean concrete placed over the surface of the glacial outwash deposit following the removal of all existing topsoil material, fill material, existing foundation remains and structures from below the proposed footing locations. Footings should be proportioned utilizing an allowable design net bearing pressure of two (2) tons per square- foot. The lowest level slab is recommended to consist of a conventional soil-supported slab- on-grade. In consideration of the lowest level slab being below the existing grade along Main Street it is recommended that perimeter and underslab foundation drainage be provided. Other detailed geotechnical engineering recommendations and criteria for foundation design are documented in the report, as well as foundation construction considerations such as temporary support of excavation, preparation of foundation and slab bearing surfaces, dewatering and on-site reuse of excavated soil. Furthermore, construction monitoring considerations are also presented herein. Winn Development August 22, 2023 Page 2 GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERS 2269 Massachusetts Avenue Cambridge, Massachusetts 02140 (617) 868-1420 We look forward to continued participation with the design team during the remainder of the project. Should you have any questions concerning the recommendations presented herein, please do not hesitate to call us. Very truly yours, McPHAIL ASSOCIATES, LLC Anna M. Pelletier Jonathan W. Patch, P.E. N:\Working Documents\Reports\7682_307MainStreetHyannis_FER_082223.docx AMP/jwp CONTENTS: 1.0 - INTRODUCTION.................................................................................................1 1.1 - GENERAL................................................................................................1 1.2 – PURPOSE AND SCOPE..............................................................................1 1.3 – AVAILABLE INFORMATION........................................................................1 1.4 – ELEVATION DATUM .................................................................................1 2.0 – SITE AND PROJECT DESCRIPTION.......................................................................2 2.1 – EXISTING SITE CONDITIONS....................................................................2 2.2 – PROPOSED DEVELOPMENT .......................................................................2 3.0 – SUBSURFACE EXPLORATIONS.............................................................................2 4.0 – SUBSURFACE CONDITIONS ................................................................................3 4.1 – SOIL CONDITIONS ..................................................................................3 4.2 – GROUNDWATER CONDITIONS...................................................................3 4.3 – RAWLS INFILTRATION RATES ...................................................................4 5.0 – GEOTECHNICAL RECOMMENDATIONS ..................................................................5 5.1 – FOUNDATION DESIGN RECOMMENDATIONS ...............................................5 5.2 – RECOMMENDATIONS FOR OVEREXCAVATION..............................................5 5.3 – LOWEST LEVEL SLAB RECOMMENDATIONS.................................................7 5.4 – RADON VENTILATION SYSTEM..................................................................7 5.5 – GROUNDWATER CONSIDERATIONS ...........................................................7 5.6 – RESISTANCE TO LATERAL FORCES ............................................................8 5.7 – SEISMIC DESIGN CONSIDERATIONS .........................................................9 6.0 – FOUNDATION CONSTRUCTION CONSIDERATIONS.................................................9 6.1 – GENERAL RECOMMENDATIONS .................................................................9 6.2 – TEMPORARY SUPPORT OF EXCAVATION .....................................................9 6.3 – PREPARATION AND PROTECTION OF FOOTING BEARING SURFACES ............10 6.4 – PROOF-COMPACTION OF SUBGRADES......................................................10 6.5 – EXISTING FOUNDATION REMAINS...........................................................11 6.6 – RELOCATION OF EXISTING UTILITIES......................................................11 6.7 – GROUNDWATER CONTROL......................................................................11 6.8 – REUSE OF ON-SITE SOILS......................................................................11 6.9 – OFF-SITE REMOVAL OF EXCESS SOILS.....................................................12 7.0 – FUTURE WORK................................................................................................13 7.1 – ADDITONAL BORINGS............................................................................13 7.2 – DESIGN ASSISTANCE ............................................................................13 7.3 – CONSTRUCTION OBSERVATION ..............................................................13 8.0 – LIMITATIONS..................................................................................................14 FIGURES: FIGURE 1: PROJECT LOCATION PLAN FIGURE 2: SUBSURFACE EXPLORATION PLAN FIGURE 3: GRAIN SIZE DISTRIBUTION – FILL MATERIAL FIGURE 4: GRAIN SIZE DISTRIBUTION – GLACIAL OUTWASH FIGURE 5: LIMITS OF STRUCTURAL FILL AND LEAN CONCRETE FIGURE 6: FOUNDATION DRAINAGE PLAN FIGURE 7: LATERAL PRESSURES FOR DESIGN OF BELOW-GRADE WALLS APPENDICES: APPENDIX A: EXPLORATION AND LABORATORY TESTING PROCEDURES APPENDIX B: BORING LOGS APPENDIX C: GROUNDWATER MONITORING REPORTS FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 1 1.0 - INTRODUCTION 1.1 - GENERAL This report presents the results of our subsurface exploration program and foundation design study for the proposed residential development to be located at 307 Main Street in Hyannis, Massachusetts. Refer to the Project Location Plan, Figure 1, for the general site locus. The subsurface exploration program was conducted and the foundation engineering services were performed in accordance with our proposal for geotechnical engineering services dated May 11, 2023 and the subsequent authorization of Winn Development. These services are subject to the limitations contained herein. 1.2 – PURPOSE AND SCOPE The purpose of the subsurface exploration program and foundation engineering study was to document the subsurface soil and groundwater conditions at the site to provide geotechnical engineering recommendations for economical foundation design for the proposed redevelopment. Foundation design includes foundation support of the proposed building structure and the lowest level slabs, treatment of the lowest level slabs in consideration of groundwater, lateral earth pressures on foundation walls, and seismic design considerations in accordance with the provisions of the Ninth Edition of the Massachusetts State Building Code (Code). Foundation construction considerations relating to geotechnical aspects of the proposed construction are also presented herein. 1.3 – AVAILABLE INFORMATION Information available to McPhail Associates, LLC (McPhail) included the following: •A 20-scale site survey entitled “Existing Conditions Plan” prepared by Baxter Nye Engineering and Surveying and dated January 10, 2022. •A set of architectural drawings entitled “Harbor Vue” prepared by Icon Architecture and dated July 26, 2023. •A report entitled “Phase I/Phase II Environmental Site Assessment Report, 307 Main Street, Hyannis, Massachusetts” prepared by McPhail and dated July 31, 2023. 1.4 – ELEVATION DATUM Elevations cited herein are in feet and are referenced to the North American Vertical Datum of 1988 (NAVD88). FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 2 2.0 – SITE AND PROJECT DESCRIPTION 2.1 – EXISTING SITE CONDITIONS Fronting onto Main Street to the north, the approximately 1.76-acre subject property is bounded by Old Colony Road to the east, commercial properties to the west, and mixed-use residential properties to the south. The subject property is currently occupied by a vacant two (2)-story office building with a footprint of about 13,600-square-feet with a basement. Based on the available information, it is anticipated that the lowest level slab is located at approximate Elevation +28. The areas surrounding the existing building consist of paved parking lots with landscaped margins. Ground surface across the subject property slopes gradually upwards from east to west from approximate Elevation +29 to Elevation +36. 2.2 – PROPOSED DEVELOPMENT The proposed redevelopment of the subject site is understood to include the demolition of the existing building and the construction of a new four (4)-story, irregularly-shaped multi- unit residential building which is planned to occupy a footprint of approximately 33,170- square-feet. The first floor will consist of amenity space and an open-air parking area which will occupy approximate plan areas of 13,380 and 19,790-square-feet, respectively. The remaining three (3) floors are planned to consist of residential units. It is understood that the proposed building will not contain a below-grade level, however it will be benched into the surrounding site grade and portions of the slab will be below-grade. Specifically, the lowest-level slab is proposed to be located at approximate Elevation +29.5 and may be approximately 6 feet lower than the site grade along Main Street to the north. The proposed building will be surrounded by bituminous paved access roads and parking areas and landscaped margins. 3.0 – SUBSURFACE EXPLORATIONS The approximate location of the subsurface explorations is indicated on the enclosed Subsurface Exploration Plan, Figure 2. The following subsurface explorations were completed at the project site under contract to McPhail: •Six (6) borings (B-1 through B-6) completed on July 13, 14, and 17, 2023 by Carr-Dee Corp. Exploration procedures and soil classification methods are contained in Appendix A. The borings were drilled to depths ranging from 17 to 62 feet below the existing ground surface and were terminated within a natural glacial outwash deposit. Boring logs are contained in Appendix B. Groundwater observation wells were installed within completed borings B-3(OW), B-4(OW) and B-5(OW). Groundwater Monitoring Reports are contained in Appendix C. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 3 4.0 – SUBSURFACE CONDITIONS 4.1 – SOIL CONDITIONS A detailed description of the subsurface conditions encountered in the explorations is documented on the logs contained in the Appendices as described above. Based on the explorations performed at the site, the following is a description of the generalized subsurface conditions across the site encountered from ground surface downward. Generalized Subsurface Strata Approximate Thickness (Feet) Top of Soil Strata (Elevation) Asphalt or Topsoil 0.2 to 2.0 Ground Surface (El. +36.9 to El. +28.7) Fill 5.6 to 9.2 El. +36.4 to El. +26.7 Glacial Outwash Not Fully Penetrated El. +29.5 to El. 20.7 Fill Material: The fill material generally consists of very loose to very dense, light brown to dark brown, sand and gravel with trace to some silt, varying to silty sand with some gravel, also containing varying amounts of concrete, organics, brick, ash, and cinders. Grain size distributions of samples of the fill material are presented in the enclosed Figure 3. Glacial Outwash Deposit: The glacial outwash deposit which underlies the fill material and generally consists of compact to very dense, yellow brown to brown, gravelly sand with trace silt varying to sand with some gravel and trace silt. Refer to Figure 2 for the elevation of the top of the glacial outwash deposit at each exploration location. Each boring was terminated within the natural, inorganic glacial outwash deposit. Grain size distributions of samples of the glacial outwash deposit are presented in the enclosed Figure 4. 4.2 – GROUNDWATER CONDITIONS The groundwater level in the completed boreholes and observation wells was observed to range from about Elevation +12.2 to +11.4, corresponding to depths of 16.5 feet below ground surface and 23.7 feet below ground surface, respectively. Groundwater monitoring reports for the three (3) observation wells installed by McPhail at the subject site are contained in Appendix C. It is anticipated that future groundwater levels across the site may vary from those reported herein due to factors such as normal seasonal changes, runoff particularly during or following periods of heavy precipitation, and alterations of existing drainage patterns. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 4 4.3 – RAWLS INFILTRATION RATES Based on the laboratory grain-size distributions of soil samples obtained from the recent test pits, the soil texture class was determined using the USDA textural triangle. The soil texture class was then used to determine the Rawls Infiltration Rates. It is understood that the Rawls Infiltration Rates are based on research performed by Rawls, Brakensiek, and Sexton in 1982 which used laboratory permeability testing to develop a relationship between texture class and saturated permeability. The table below contains information regarding the USDA soil texture class for each sample tested and the corresponding Rawls Infiltration Rate, based on the grain size distribution results (attached). Boring Sample Elevation (ft) Sample Depth (ft)Strata USDA Soil Texture Class Corresponding Rawls Infiltration Rate (in/hr) B-1 +34.9 2.0 to 4.0 Fill Sand 8.27 B-4(OW)+33.5 2.0 to 4.0 Fill Sand 8.27 B-5(OW)+34.7 0.5 to 2.0 Fill Loamy Sand 2.41 B-3(OW)+26.1 9.0 to 11.0 Glacial Outwash Sand 8.27 B-4(OW)+29.5 6.0 to 8.0 Glacial Outwash Sand 8.27 B-5(OW)+25.2 10.0 to 12.0 Glacial Outwash Sand 8.27 B-6 +24.1 10.0 to 12.0 Glacial Outwash Loamy Sand 2.41 FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 5 5.0 – GEOTECHNICAL RECOMMENDATIONS 5.1 – FOUNDATION DESIGN RECOMMENDATIONS Based on the scope of the proposed construction and the subsurface conditions encountered at the site, it is recommended that the proposed structure be founded on conventional footing foundations bearing directly on the undisturbed, natural glacial outwash or on compacted crushed stone, compacted structural fill, or lean concrete placed over the surface of the glacial outwash deposit following the removal of all existing topsoil material, fill, foundation remains and structures from below the proposed footing locations. The following parameters are recommended for the design of the new foundations: •Footings should be proportioned utilizing an allowable design net bearing pressure of two (2) tons per square-foot. •The minimum footing width for perimeter footings and isolated footings should be 24 inches and 36 inches, respectively. •Perimeter foundations and interior foundations below unheated areas should be provided with a minimum 4-foot thickness of soil cover as frost protection. Interior foundations below heated areas should be located such that the top of foundation concrete is a minimum of six inches below the underside of the lowest level slab. o It is anticipated that the parking level will be unheated, and, therefore, the 4-foot thickness of soil cover would apply to most foundations. •Foundations should be located such that they bear below a theoretical line drawn upward and outward at 2 to 1 (horizontal to vertical) from the bottom exterior edge of all adjacent existing or proposed footings, structures and/or utilities. •Foundations should be designed in accordance with the Code. 5.2 – RECOMMENDATIONS FOR OVEREXCAVATION As stated above, all existing topsoil material, fill, foundation remains and structures must be removed from below proposed footing locations. Based on the available subsurface information, the surface of the glacial outwash is anticipated to range from approximately Elevation +29.5 to Elevation +20.7. Based on the available information, it is anticipated that the lowest level slab of the existing building is located at approximate Elevation +28 and that the surface of the natural glacial outwash deposit may be up to 2 feet below the existing lowest level slab. Refer to Figure 2 for the elevation of the top of the glacial outwash deposit at each exploration location. Anticipating that design bottom of footing elevation will generally be at around Elevation +25.5, up to about 5 feet of overexcavation may be required, primarily on the eastern wing of the building footprint, to reach the surface of the glacial outwash deposit. Elsewhere, it is anticipated that none to minimal overexcavation will be required at footing locations based on the boring information. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 6 At locations where the surface of the glacial outwash is greater than 3 inches beneath the proposed bottom of footing elevation, structural fill or lean concrete should be used as backfill up to the 3-inch thickness of crushed stone that is placed below the design subgrade. In general, it is anticipated that structural fill will be the preferred option, however, lean concrete may be required if the zone of influence of structural fill cannot be achieved, particularly adjacent to the property line and surrounding roadways. The following parameters are recommended for the use of structural fill or lean concrete for support of proposed footings: •Structural Fill o Refer to the attached Figure 5 for the required lateral and vertical limits of structural fill for support of spread footings which are as follows: ▪The plan limits of the placement of structural fill should extend laterally beyond the edges of the footings for a horizontal distance equal to the depth measured from the design bottom of footing elevation to the surface of the natural, inorganic glacial outwash deposit, plus two feet. •Example: where the surface of the natural soil is 4 feet below the design bottom of footing elevation, compacted structural fill will be required to extend laterally outward from the edge of the footing for a horizontal distance of 6 feet. o Structural fill should consist of either suitable existing on-site granular fill or glacial outwash, or an off-site gravel borrow which consists of a well-graded sand and gravel with less than 8 percent by weight passing the No. 200 sieve. o All structural fill placed within the footprint of the proposed development should be placed in lifts having a compacted thickness of 6 inches and be compacted to a minimum of 95 percent of its modified Proctor maximum dry density. •Lean Concrete o Refer to the attached Figure 5 for the required lateral and vertical limits of lean concrete for support of footings which are as follows: ▪The bearing area of the lean concrete placed on the undisturbed glacial outwash deposit should extend at least 6 inches beyond the edge of the footing. o Lean concrete should have a minimum compressive strength of 1,000 pounds per square-inch. All structural fill and lean concrete will need to be placed in the dry on an undisturbed bearing surface. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 7 5.3 – LOWEST LEVEL SLAB RECOMMENDATIONS The lowest-level slabs of the ground-level non-parking areas of the building are recommended to consist of conventional soil-supported slabs-on-grade underlain by a polyethylene vapor barrier spread across the surface of a minimum 10-inch thickness of compacted 3/4-inch crushed stone placed over a proof-compacted subgrade as indicated below. In the locations of the building slabs, the surficial site improvements and topsoil would be removed, however the existing fill can be left in place, except for where it is removed at footing locations. Furthermore, the existing fill subgrade would be proof-compacted as discussed in the Foundation Construction Considerations section below. Due to the presence of the existing fill located beneath the slabs, there is potential for minor settlement and cracking of the proposed slabs due to the uncontrolled and variable nature of these materials. Preparation of the subgrade for support of the open-air parking at grade level of the building should include the removal of any existing surface treatments and proofrolling of the existing fill subgrade below the depth of the required base and subbase courses with at least four (4) passes of a 10-ton vibratory drum roller. All soft or compressible areas detected by the proofrolling should be excavated and replaced with a compacted, off-site gravel borrow. 5.4 – RADON VENTILATION SYSTEM We recommend the installation of a sub-slab radon ventilation system within the proposed building. The radon ventilation system should consist of 4-inch diameter perforated PVC pipe laid flat within the 10-inch thick layer of crushed stone, or a low profile venting composite such as Geovent or approved equivalent that underlies the proposed slabs. The radon systems should include vertical riser pipe, consisting of solid PVC pipe within the interior of the building. It is anticipated that this system could be designed as a passive radon mitigation system which could be converted to an active mitigation system in the future, if required. 5.5 – GROUNDWATER CONSIDERATIONS In consideration of the lowest level slab being partially below the existing grades along Main Street and proposed exterior finished grades, it is recommended that perimeter and underslab foundation drainage be provided for portions of the building. The perimeter and underslab foundation drains are intended to minimize groundwater intrusion into the lowest level space which is planned to be below the exterior site grade along Main Street due to conditions when groundwater may become temporarily elevated due to precipitation events, surface water run-off, and/or seasonal groundwater changes. The underslab and perimeter drainage systems are not intended to lower the existing groundwater level. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 8 A conceptual foundation drainage detail is attached as Figure 6. In addition, the following is recommended for the design of the perimeter and underslab drains: •The perimeter and underslab drainage systems should consist of 4-inch diameter perforated PVC pipe. •The drainage systems should have highest invert elevations a minimum of 12 inches below the underside of the lowest level slab. •Where possible, the drainage pipes should be pitched down at a minimum 0.5 percent slope in the direction of flow. •The perimeter drainage pipes should be surrounded by a minimum 6-inch thickness of 3/4-inch crushed stone surrounded by a thickness of filter fabric such as Mirafi 140N, or equivalent. •The underslab drainage pipes should be located within the crushed stone drainage layer beneath the lowest level slab and should be surrounded by a minimum of 6-inch thickness of 3/4-inch crushed stone. o Localized trenching will be required at the underslab drainage pipe locations. •The perimeter and underslab drain lines should be gravity drained to a storm drain line that is not subject to surcharge or terminated within a sump pit that discharges into the storm drain system. o The sump pit should be equipped with duplex pumps, a high-water alarm, and a backup power supply. o The recommended design discharge flow rate from the foundation drainage system is 40 gallons per minute (gpm). All below-grade walls should receive a troweled-on bitumastic damp-proofing. A prefabricated drainage product, such as Miradrain 6000, should be installed directly against the below-grade perimeter foundation walls and be tied into the perimeter drainage system. Backfill against the perimeter foundation walls may consist of ordinary fill. Additionally, the exterior site grades should be sloped away from the perimeter of the proposed addition to minimize surface water infiltration. All pits and depressions extending below the slab (e.g., elevator pits, etc.) should be provided with properly tied continuous waterstops in all construction joints and be waterproofed. Also, pits and depressions below the slab should be designed for hydrostatic uplift pressures corresponding to the groundwater being present 1-foot below the bottom of the proposed slab. 5.6 – RESISTANCE TO LATERAL FORCES Refer to the attached Figure 7 for lateral pressure diagrams for use in the design of below- grade walls. Specifically, below-grade foundation walls receiving lateral support at the top and bottom (i.e., restrained walls) that are provided with positive drainage should be FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 9 designed for a lateral earth pressure corresponding to an equivalent fluid density of 60 pounds per cubic foot (pcf). To these values must be added the pressures attributable to earthquake forces per Section 1610.2 of the Code plus any permanent surcharge loads, if applicable. Lateral forces can be transmitted from the structure to the soil by passive pressure on the footings utilizing an equivalent fluid density of 120 pcf providing that these structural elements are designed to resist these pressures. Lateral forces can also be considered to be transmitted from the structure to the soil by friction on the base of the footings using a frictional coefficient of 0.4 to which a factor of safety of 1.5 should be applied. 5.7 – SEISMIC DESIGN CONSIDERATIONS For the purposes of determining parameters for structural seismic design, this site is considered to be a Site Class D as defined in Chapter 20 of American Society of Civil Engineers (ASCE) Standard 7-10 “Minimum Design Loads for Buildings and Other Structures”. Further, the bearing strata on the proposed site are not considered to be subject to liquefaction during an earthquake based on the criterion of Section 1806.4 of the Code. 6.0 – FOUNDATION CONSTRUCTION CONSIDERATIONS 6.1 – GENERAL RECOMMENDATIONS This section addresses geotechnical aspects of the proposed foundation construction which are considered by McPhail to be critical to proper foundation performance of the completed development as well as mitigating potential adverse foundation construction impacts on surrounding buildings, streets, utilities, and other site improvements, as applicable. Prospective contractors should be provided with the following information regarding the foundation construction considerations; however, each contractor should perform an independent assessment based on their own equipment, personnel, and anticipated procedures with input from specialty foundation subcontractors. 6.2 – TEMPORARY SUPPORT OF EXCAVATION Based on the grade along Main Street and the anticipated bottom of footing elevations, cuts of up to 10 feet below existing ground surface may be required to construct the proposed development, specifically on the northern portion of the proposed building. Given the proximity of the proposed building to Main Street and the estimated subgrade elevations, there is likely insufficient space to slope or bench the excavations along Main Street. Therefore, temporary excavation support may be required along the northern perimeter of the proposed building. Depending on contractor staging, portions of the excavation may be able to be open cut. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 10 Where required, the temporary excavation support system is likely to consist of a cantilevered steel soldier pile and timber lagging wall or steel sheet piling. Depending on the sensitivity of adjacent structures to noise and vibration from soldier pile installation, the soldier piles could be drilled-in to reduce noise and vibration impacts to adjacent structures. Drilled soldier piles may also be necessary to provide sufficient toe embedment to adequately support the excavation. The temporary earth support system should be designed by a professional engineer registered in the Commonwealth of Massachusetts who is employed by the Contractor. The design should be based on design parameters to be provided in the Contract Documents and on the Contractor's anticipated construction sequence and procedures which should account for applicable construction and traffic surcharge loads. The design should be submitted to the Architect for review prior to the commencement of construction. Where required, the temporary excavation support wall should be offset approximately 5 feet from the exterior basement walls of the structure to facilitate two-sided forming for the perimeter foundation walls, unimpeded open excavation, the installation of damp-proofing on the basement walls, and placement of backfill. Following completion of the backfilling operations, the excavation support system should remain in-place and be cut-off four (4) feet below finished grade. Removal of the steel soldier piles or sheeting could cause settlement of the building due to densification of the existing soils from vibrations. Depending on the horizontal distance between the outside edge of footing and the temporary earth support system, the minimum lateral limits of structural fill may not be achievable, and if such, the footing will need to be lowered and/or lean concrete used in lieu of structural fill. 6.3 – PREPARATION AND PROTECTION OF FOOTING BEARING SURFACES As discussed, preparation of footing bearing surfaces for the proposed building should include the removal of all existing topsoil material, fill, foundation remains and structures to expose the undisturbed, natural glacial outwash deposit. Furthermore, all existing topsoil should be entirely stripped from proposed building footprint and paved areas. Bearing surfaces consisting of glacial outwash or structural fill should be excavated using an excavator that is equipped with a smooth-edged bucket (smooth, toothless cutting edge or a steel plate welded across the teeth) to avoid disturbance of the bearing surface. Further, it is recommended that as soon as the bearing surface is exposed, it be immediately covered with a minimum 3-inch thickness of compacted ¾-inch crushed stone to prevent disturbance of the subgrade during subsequent forming operations. 6.4 – PROOF-COMPACTION OF SUBGRADES For preparation of the subgrade soils consisting of the existing fill, where it may remain place as described herein, the exposed subgrade should be proof-compacted with at least four passes of a double-drum vibratory roller or large vibratory plate compactor. All soft FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 11 and/or compressible areas detected by the proof-compaction should be excavated and replaced with compacted structural fill. 6.5 – EXISTING FOUNDATION REMAINS The structures which currently occupy the subject site will be demolished as part of the proposed development. Existing foundation remains should be removed where they interfere with new construction. Foundation remains may remain in place where they do not interfere with the proposed structure provided that they are removed to 24 inches beneath the proposed finished grade. 6.6 – RELOCATION OF EXISTING UTILITIES Where existing utilities and structures are located within the footprint of the proposed building, they should be relocated prior to construction. The resulting abandoned utility/structure and associated backfill should be removed and replaced with compacted structural fill. 6.7 – GROUNDWATER CONTROL Proper control of surface water run-off will be necessary to maintain a firm subgrade to support construction traffic. In consideration that groundwater was observed within the completed borings and groundwater observation wells at depths ranging between 16.5 to 23.7 feet below ground surface, corresponding to between Elevation +12.2 to +11.4, respectively, it is not anticipated that significant groundwater control will be required during the construction period. Dewatering by means of conventional sumping should suffice for groundwater control during periods of high precipitation. It is recommended that all pumped groundwater be recharged on-site. If pumped groundwater cannot be recharged on-site, it would be necessary to dispose of pumped groundwater into a nearby storm drain or combined sewer which would require the need for a temporary construction dewatering discharge permit. 6.8 – REUSE OF ON-SITE SOILS It is anticipated that portions of the excavated granular fill and glacial outwash may be re-used on-site as ordinary fill and structural fill, provided they are maintained in a dry condition and can be properly compacted. Excavated granular fill and glacial outwash material to be reused on-site as structural fill should typically contain less than 20% by weight passing the No. 200 sieve. Excavated soil with greater than 20% by weight passing the No. 200 sieve should be segregated and can be reused on-site as ordinary fill subject to the provisions contained herein. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 12 Structural fill should consist of inorganic excavated on-site fill or glacial outwash material and should conform to the following gradation requirements: U.S. Sieve No.Percent Passing by Weight 4”100 1”60 – 100 #4 25 – 95 #40 5 – 50 #200 0 – 20 It is recommended that stockpiles of excavated material intended for on-site reuse be protected against increases in moisture content by securely covering the stockpiles at all times with 6-mil polyethylene for protection from precipitation and also as a dust mitigation measure. The placement and compaction of on-site material should be completed during relatively dry and non-freezing conditions. If the earthwork operations are performed during a wet and/or cold period, it is anticipated that portions of the on-site soil may become unsuitable for re-use on-site. If, due to any of the above conditions, the excavated material is unsuitable for reuse, an off-site gravel borrow should be used. Gravel borrow should consist of a well-graded, natural sand and gravel from an off-site source, conforming to the following gradation requirements: U.S. Sieve No.Percent Passing by Weight 3”100 ½”50 – 85 #4 40 – 75 #50 8 – 28 #200 0 – 8 Due to the presence of organic material (roots) in the existing topsoil, we do not recommend reusing this material as structural fill beneath footings or the slabs-on-grade. The on-site existing topsoil may be reused as ordinary fill in landscaped areas, provided it is protected from wet and freezing environments and can be compacted to the recommended densities. However, given that sufficient space on site to stockpile topsoil is likely not available, as a practical basis it is anticipated that the topsoil will be removed from the site. 6.9 – OFF-SITE REMOVAL OF EXCESS SOILS Construction of the proposed building will generate excess soil that will require off-site removal. When off-site removal of excess soil is required, it should be performed in accordance with the current policies of the Massachusetts Department of Environmental Protection. It is recommended that McPhail be retained to prepare a Soil Management Plan which would contain details regarding the off-site removal of soils from the project site. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 13 7.0 – FUTURE WORK 7.1 – ADDITONAL BORINGS It is recommended that additional borings be performed to further delineate the surface of the natural glacial outwash deposit in the vicinity of the proposed building footprint, particularly in the eastern portion of the building where the surface of the natural glacial outwash was observed in the borings to be lower. Should geoenvironmental explorations be performed as part of a soil pre-characterization program, it may be possible to use these explorations to determine this information. 7.2 – DESIGN ASSISTANCE McPhail has been retained to provide design assistance to the design team during the final design phase of this project. The purpose of this involvement is to review the structural foundation drawings and foundation notes for conformance with the recommendations presented herein and to generate the geotechnical-related specification sections for inclusion into the Contract Documents for construction. 7.3 – CONSTRUCTION OBSERVATION It is recommended that McPhail be retained during the construction period to observe the installation of the temporary earth support system, over-excavation of unsuitable soils, final preparation of the foundation bearing surfaces, preparation of the slab-on-grade subgrade, installation of the perimeter and underslab drainage systems, and the placement and compaction of structural fill in accordance with the provisions of the Code and the provisions of the Contract Documents. Our involvement during the construction phase of the work should minimize costly delays due to unanticipated field problems since our field representative would be under the direct supervision of our project manager who was responsible for the subsurface explorations and foundation design recommendations documented herein. FOUNDATION ENGINEERING REPORT 307 MAIN STREET AUGUST 22, 2023 PAGE 14 8.0 – LIMITATIONS This report has been prepared in accordance with generally accepted soil and geotechnical engineering practices. No other warranty, expressed or implied, is made. If any changes in nature or design of the proposed construction are planned, the conclusions and recommendations contained in this report should not be considered valid unless the changes are reviewed and conclusions of this report modified or verified in writing by McPhail. The analyses and recommendations presented in this report are based upon the data obtained from the subsurface explorations performed at the approximate locations indicated on the enclosed plan. If variations in the nature and extent of subsurface conditions between the widely spaced explorations become evident during construction, it will be necessary for a re-evaluation of the recommendations of this report to be made after performing on-site observations during the construction period and noting the characteristics of any variations. FIGURES SITE PROJECT LOCATION PLAN FIGURE 1 SCALE 307 MAIN STREET HYANNIS MASSACHUSETTS1:25,000 B-1B-2B-4 (OW)B-5 (OW)B-6+36.9+27.4NE+28.7+20.7+12.2+34.1+28.1NE+35.1+28.1+11.5+35.5+29.5+12.0+35.2+28.1+11.5APPROXIMATE LIMITSOF EXISTING BUILDINGB-3 (OW)APPROXIMATE LIMITSOF SUBJECT PROPERTYAPPROXIMATE LIMITS OFPROPOSED BUILDINGMcPHAIL ASSOCIATES, LLCFORBYFILE NAME:FIGUREN:\Acad\JOBS\7682\7682-F02.dwg 76821" = 20'A.M.P.M.B.S.JULY 2023WINN DEVELOPMENTSUBSURFACE EXPLORATION PLANMASSACHUSETTSHYANNIS307 MAIN STREET2N O R T H0 GRAPHIC SCALE20204080APPROXIMATE LOCATION OF BORING PERFORMED BY CARR-DEE CORP. ON JULY 13, 14,AND 17, 2023 FOR MCPHAIL ASSOCIATES, LLCINDICATES OBSERVATION WELL INSTALLED WITHIN COMPLETED BOREHOLE(OW)+28.7+20.7+12.2ELEVATION OF GROUNDWATER OBSERVED IN BORING. NE - INDICATES GROUNDWATERNOT ENCOUNTEREDELEVATION OF NATURAL GLACIAL OUTWASH DEPOSITELEVATION OF GROUND SURFACEREFERENCE: THIS PLAN WAS PREPARED FROM A 20-SCALE DRAWING ENTITLED, "EXISTING CONDITIONSPLAN" DATED JANUARY 10, 2022 PREPARED BY BAXTER NYE ENGINEERING AND SURVEYING LEGEND McPHAIL ASSOCIATES, LLCFIGUREFILE NAME:N:\Acad\JOBS\7682\7682-F03_Sieve.dwg7682FILL3B-1S-22.0'-4.0'B-4S-22.0'-4.0'B-5S-10.5'-2.0' McPHAIL ASSOCIATES, LLCFIGUREFILE NAME:N:\Acad\JOBS\7682\7682-F04_Sieve.dwg7682GLACIAL OUTWASH4B-3S-59.0'-11.0'B-4S-46.0'-8.0'B-5S-510.0'-12.0'B-6S-510.0'-12.0' 2.0'DD11STRUCTURAL FILLFOOTING SECTION A-A NATURAL, UNDISTURBED INORGANIC BEARING MATERIAL PLAN FOOTINGASTRUCTURAL FILLA PLAN FOOTINGAA0.5'0.5'LEAN CONCRETEFOOTING SECTION A-A NATURAL, UNDISTURBED INORGANIC BEARING MATERIALNON-BEARING MATERIALNON-BEARING MATERIAL0.5'LEAN CONCRETEMINIMUM LIMITS OF STRUCTURAL FILL BELOW FOOTINGSMINIMUM LIMITS OF LEAN CONCRETE BELOW FOOTINGSFORBYMcPHAIL ASSOCIATES, LLCFIGUREN:\Acad\JOBS\7682\7682-F05.dwgFILE NAME:307 MAIN STREETHYANNISMASSACHUSETTSLIMITS OF STRUCTURAL FILL AND LEAN CONCRETEWINN DEVELOPMENTAUGUST 2023M.B.S.A.M.P.N.T.S.76825 PERIMETER FOUNDATION WALLPROPOSED FINISHED GRADESLOPEDAMP PROOFINGSLOPE AS REQUIREDFOR STABILITYCOMPACTED ORDINARY FILLPREFABRICATED DRAINAGE BOARD(MIRADRAIN 6000 OR EQUAL)BELOW-GRADE LEVELVAPOR BARRIER(BY OTHERS)1' MIN.4" DIA. PERFORATEDPVC PIPE1' MIN.6" MIN. CRUSHEDSTONE AROUND PIPE4" DIA. PERFORATEDPVC PIPE1' MIN.FILTER FABRIC (MIRAFI140N OR EQUAL)6" MIN.1' MIN.6" MIN. OF 3/4" CRUSHEDSTONE AROUND PIPECOMPACTED ORUNDISTURBED SUBGRADE3/4" CRUSHED STONE PERIMETER AND UNDERSLAB DRAINAGE DETAIL N.T.S.DO NOT EXCAVATEBELOW THIS LINE21SLAB-ON-GRADE9"FILTER FABRIC(MIRAFI 140NOR EQUAL)FLOOR SLABFORBYMcPHAIL ASSOCIATES, LLCCONSULTING GEOTECHNICAL ENGINEERSFIGUREFILE NAME:N:\Acad\JOBS\7682\7682-F06.dwg307 MAIN STREETHYANNISMASSACHUSETTSFOUNDATION DRAINAGE DETAILWINN DEVELOPMENTAUGUST 2023M.B.S.A.M.P.N.T.S.76826NOTE:THE ABOVE IS PROVIDED AS A CONCEPTUAL FOUNDATION DRAINAGEDETAIL. PLEASE REFER TO THE CONTRACT DOCUMENTS FOR THEPROJECT FOUNDATION DRAINAGE DESIGN AND REQUIREMENTS. AT-REST EARTH PRESSURES (UNDRAINED FOUNDATION WALL) FINAL GROUNDSURFACEGROUNDLEVEL SLABLOWESTLEVEL SLAB60HHH ACTIVE EARTH PRESSURES (UNDRAINED CANTILEVER RETAINING WALL) 40H HYDROSTATIC PRESSURES (UNDRAINED FOUNDATION AND RETAINING WALLS) AT-REST EARTH PRESSURES (DRAINED FOUNDATION WALL) 60HH ACTIVE EARTH PRESSURES (DRAINED CANTILEVER RETAINING WALL) 40H EARTHQUAKE PRESSURES 212SatWHERE:S - SPECTRAL RESPONSE ACCELERATIONF - SITE COEFFICIENTɤ - TOTAL UNIT WEIGHT OF SOILStaDRAINAGEFINAL GROUNDSURFACEFINAL GROUNDSURFACEFINAL GROUNDSURFACEGROUNDLEVEL SLABLOWESTLEVEL SLABHHHFINAL GROUNDSURFACEGROUNDLEVEL SLABLOWESTLEVEL SLABFINAL GROUNDSURFACEFINAL GROUNDSURFACEHH211GROUNDLEVEL SLABLOWESTLEVEL SLAB(2)(0.1)(S )(F )(ɤ )H40H + 20H2160H + 30H2262.4HFINAL GROUND SURFACEDRAINAGE11NOTES:1.THESE PRESSURE DIAGRAMS ARE INTENDED FOR USE INDESIGNING BELOW-GRADE FOUNDATION WALLS ANDRETAINING WALLS FOR THE PERMANENT CONDITIONS.2.VALUES OF PRESSURE IN THESE DIAGRAMS ARE IN UNITSOF POUNDS PER SQUARE FOOT.3.AN EQUIVALENT FLUID DENSITY OF 120 POUNDS PERCUBIC FOOT IS RECOMMENDED FOR PASSIVE EARTHPRESSURES.4.PRESSURE DIAGRAMS ASSUME AN ANGLE OF INTERNALFRICTION OF 30 DEGREES AND A TOTAL UNIT WEIGHT OF 120 POUNDS PER CUBIC FOOT.5.LATERAL PRESSURES RESULTING FROM ADJACENTVERTICAL SURCHARGE LOADS SHOULD BE INCLUDED INTHE DESIGN OF BELOW-GRADE FOUNDATION WALLS ANDRETAINING WALLS WHERE APPLICABLE.6.H = DISTANCE FROM EXTERIOR GROUND SURFACE FOR FOUNDATION WALLS OR RETAINED GROUND SURFACE FOR RETAINING WALLS TO DESIGN GROUNDWATER ELEVATION. H = DISTANCE FROM DESIGN GROUNDWATER ELEVATION TO TOP OF LOWEST LEVEL SLAB FOR FOUNDATION WALLS OR TO UNRETAINED GROUND SURFACE FOR RETAINING WALLS. H = DISTANCE FROM EXTERIOR GROUND SURFACE TO TOP OF LOWEST LEVEL SLAB FOR FOUNDATION WALLS OR FROM RETAINED GROUND SURFACE TO UNRETAINED GROUND SURFACE FOR RETAINING WALLS.= DENOTES DESIGN GROUNDWATER ELEVATION.7. REFER TO REPORT TEXT FOR DESIGN GROUNDWATERELEVATION.FORBYMcPHAIL ASSOCIATES, LLCFIGUREN:\Acad\JOBS\7682\7682-F07.dwgFILE NAME:307 MAIN STREETHYANNISMASSACHUSETTSLATERAL PRESSURES FOR DESIGN OF BELOW-GRADE WALLSWINN DEVELOPMENTAUGUST 2023M.B.S.A.M.P.N.T.S.7682712 APPENDIX A: EXPLORATION AND LABORATORY TESTING PROCEDURES The borings were performed using a truck-mounted drill rig and advanced utilizing hollow stem augers (HSA) and/or NW casing and the wet rotary drilling methods. Standard 2- inch O.D. split-spoon samples and standard penetration test results were obtained continuously through the fill material and then at minimum 5-foot intervals for the remainder of the boring depths. The split-spoon sampling was performed in general accordance with the standard procedures described in ASTM D1586. The explorations were monitored by McPhail field representatives who performed field layout, prepared field logs, obtained and visually classified soil samples, monitored groundwater conditions in the open boreholes and observation wells, and determined the required exploration depth based upon the actual subsurface conditions encountered. Field locations of the explorations were determined by taping from existing site features included on the available drawings. Unless noted otherwise, the existing ground surface elevation at each exploration location was determined by a level survey performed by our field staff utilizing vertical control information on the available drawings. At the completion of the field work, soil samples were returned to our laboratory for more detailed classification, analysis and testing. The laboratory testing consisted of sieve analyses to determine the gradations and confirm the visual classifications of the soil deposits. Laboratory test procedures were in general accordance with applicable ASTM Standards. SOIL CLASSIFICATION SYSTEM The soil classifications contained herein were determined using the Modified Massachusetts Institute of Technology (MIT) Soil Classification System, which utilizes the following definitions and descriptive terms to describe the soil components, percentage of soil components, and soil densities: Soil Type Grain Size Range (millimeters) Gravel 60 – 2 Sand 2 – 0.06 Silt 0.06 – 0.002 Clay <0.002 Descriptive Term Proportion of Total (%) “Trace”0 - 10 “Some”10 - 20 ADJECTIVE (e.g., sandy, silty)20 - 35 “And”35 - 50 Granular Soils Density Penetration Resistance (blows per foot) Very Loose 0 - 4 Loose 4 - 10 Compact 10 - 30 Dense 30 - 50 Very Dense >50 Cohesive Soils Density Penetration Resistance (blows per foot) Undrained Shear Strength (pounds per foot) Very Soft 0 - 2 0 - 250 Soft 2 - 4 250 - 500 Firm 4 - 8 500 - 1000 Stiff 8 - 15 1000 - 2000 Very Stiff 15 - 30 2000 - 4000 Hard >30 >4000 APPENDIX B: BORING LOGS S-1 S-2 S-3 S-4 S-5 S-5a S-6 S-7 24/18 24/11 24/16 24/18 18/16 6/6 24/16 24/16 0.0-2.0 2.0-4.0 4.0-6.0 6.0-8.0 8.0-9.5 9.5-10.0 10.0-12.0 15.0-17.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 1 3 1 3 1 6 8 11 12 14 10 7 15 16 14 25 22 45 27 37 26 19 21 20 6 6 9 8 4 14 24 30 72 74 40 15 0.5 / 36.4 9.5 / 27.4 17.0 / 19.9 Very loose to loose dark brown silty fine to medium SAND, trace gravel, organics, coal. (FILL) Compact brown SAND and GRAVEL, trace silt with concrete. (FILL) Compact yellow-brown/brown SAND and GRAVEL, trace silt. (FILL) Compact to dense yellow-brown/brown SAND and GRAVEL, trace silt. (FILL) Very dense yellow-brown/brown SAND and GRAVEL, trace silt. (FILL) Dense to very dense yellw-brown/brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Dense stratified light gray-brown fine to medium SAND, trace silt and SAND, some gravel, trace silt. (GLACIAL OUTWASH) Compact light gray-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) TOPSOIL FILL GLACIAL OUTWASH Bottom of Borehole at 17.0 feet below eixisting grade. Groundwater Observations NotesDepth NE Elev.Date 7-14-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 1 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 36.9 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 NA 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-1 GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-14-23 7-14-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 24/16 24/8 24/9 24/8 24/16 24/18 24/20 24/10 0.0-2.0 2.0-4.0 4.0-6.0 6.0-8.0 8.0-10.0 10.0-12.0 15.0-17.0 20.0-22.0 0.1 0.2 0.2 0.2 0.1 0.1 4 4 3 2 32 40 12 6 8 2 4 6 8 10 9 12 5 6 9 12 6 6 7 10 9 10 12 11 5 7 8 12 7 52 6 19 13 13 22 15 2.0 / 26.7 8.0 / 20.7 Loose brown/dark brown SAND, some silt, trace gravel. (FILL) Very dense BRICK and MORTAR to brown/dark brown SAND, some silt, trace silt. (FILL) Loose brown/dark brown silty SAND, trace silt. (FILL) Compact brown/dark brown silty SAND, trace silt. (FILL) Compact stratified light brown fine to medium SAND, trace silt and SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact stratified light brown fine to medium SAND, trace silt and SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact light gray-brown fine to medium SAND, trace silt to SAND, trace silt. (GLACIAL OUTWASH) NOTE: Split Spoon wet at ~16.6 ft. Removed Augers and replaced with NW casing. Proceeded to perform wet rotary drilling methods. Compact orange-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) TOPSOIL FILL GLACIAL OUTWASH Groundwater Observations NotesDepth 16.5 Elev. 12.2 Date 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 3 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 28.7 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-2 GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-17-23 7-17-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-9 S-10 S-11 S-12 24/9 24/20 24/18 24/13 25.0-27.0 30.0-32.0 35.0-37.0 40.0-42.0 8 7 8 9 5 7 6 8 7 8 8 9 4 6 9 13 15 13 16 15 Compact yellow-brown SAND, trace silt. (GLACIAL OUTWASH) Compact light brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact light brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact light brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact stratified light brown and orange-brown SAND, trace silt, gravel and SAND, some gravel, trace silt. (GLACIAL OUTWASH) GLACIAL OUTWASH Groundwater Observations NotesDepth 16.5 Elev. 12.2 Date 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 2 of 3 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 -17 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 28.7 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-2 GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-17-23 7-17-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-13 S-14 S-15 S-16 24/18 24/24 24/22 24/18 45.0-47.0 50.0-52.0 55.0-57.0 60.0-62.0 8 8 12 14 7 7 5 5 14 30 33 33 11 12 14 16 20 12 63 26 48.0 / -19.3 50.0 / -21.3 55.0 / -26.3 62.0 / -33.3 Stiff gray varved gray SILT, trace fine sand, fine sandy SILT and silty fine SAND. (MARINE DEPOSIT) Very dense stratified light gray, yellow-brown, brown and orange-brown fine to medium SAND, trace silt. (GLACIAL OUTWASH) NOTE: SAND and GRAVEL layer ~48-50 ft. Compact light gray-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) GLACIAL OUTWASH SAND and GRAVEL LAYER MARINE DEPOSIT GLACIAL OUTWASH Bottom of Borehole at 62.0 feet below existing grade. Groundwater Observations NotesDepth 16.5 Elev. 12.2 Date 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 3 of 3 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) -18 -19 -20 -21 -22 -23 -24 -25 -26 -27 -28 -29 -30 -31 -32 -33 -34 -35 -36 -37 -38 -39 -40 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 28.7 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-2 GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-17-23 7-17-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-1 S-2 S-3 S-4 S-5 S-6 S-7 24/16 24/20 24/16 24/18 24/20 24/13 24/15 1.0-3.0 3.0-5.0 5.0-7.0 7.0-9.0 9.0-11.0 15.0-17.0 20.0-22.0 0.1 0.1 0.1 0.1 0.1 3 3 3 5 11 21 27 62 12 21 29 24 16 15 17 20 9 11 13 17 8 11 13 16 8 10 12 12 6 48 50 32 24 24 22 0.5 / 34.6 7.0 / 28.1 Loose black ASH and CINDERS to brown SAND, some gravel, trace silt. (FILL) Dense brow/yellow-brown SAND and GRAVEL, trace silt. (FILL) Dense to very dense brown SAND, some gravel, trace silt to SAND and GRAVEL, trace silt. (FILL) Dense statified light gray-brown, brown and yelow-brown fine to medium SAND, trace silt and SAND, some gravel, trace silt. (GLACIAL OUTWASH) Compact light gray-brown SAND and GRAVEL, trace silt. (GLACIAL OUTWASH) NOTE: Advanced Augers to 9 ft. Removed Augers and replaced with NW casing to 15 ft. Perform wet rotary drilling methods for remainder of Borehole. Compact stratified light gray-brown fine to medium SAND, trace silt and SAND, trace silt, gravel. (GLACIAL OITWASH) Compact stratified light gray-brown fine to medium SAND, trace silt and SAND, trace silt, gravel. (GLACIAL OITWASH) PAVEMENT FILL GLACIAL OUTWASH Groundwater Observations NotesDepth 23.6 23.5 23.6 Elev. 11.5 11.6 11.5 Date 7-13-23 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.1 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-3 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-13-23 7-13-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-8 S-9 24/4 24/16 25.0-27.0 30.0-32.0 5 7 7 7 7 7 11 15 14 18 32.0 / 3.1 Compact light gray-brown SAND, some gravel, trace silt. (GLACIAL OUTWASH) NOTE: No recovery first attempt. Compact stratified light gray fine to medium SAND, trace silt and light gray-brown SAND, trace silt, gravel. (GLACIAL OITWASH) GLACIAL OUTWASH Bottom of Borehole at 32.0 feet below existing grade. Groundwater Observations NotesDepth 23.6 23.5 23.6 Elev. 11.5 11.6 11.5 Date 7-13-23 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 2 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 11 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.1 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-3 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-13-23 7-13-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 18/15 24/13 24/16 24/18 24/18 24/18 24/16 24/12 0.5-2.0 2.0-4.0 4.0-6.0 6.0-8.0 8.0-10.0 10.0-12.0 15.0-17.0 20.0-22.0 0.1 0.1 0.1 0.1 0.1 0.1 6 6 46 9 12 17 12 19 28 31 29 22 22 22 17 15 16 18 10 12 17 18 15 13 17 26 11 8 11 16 10 21 47 44 31 29 30 19 0.4 / 35.1 6.0 / 29.5 Loose to compact gray-black ASH and CINDERS to brown SILT and SAND. (FILL) Compact yellow-brown/brown SAND and GRAVEL, trace silt. (FILL) Dense yellow-brown/brown SAND and GRAVEL, trace silt. (FILL) Dense yellow-brown and brown fine to medium SAND, some gravel, trace silt. (GLACIAL OUTWASH) Dense stratified yellow-brown/brown and light gray fine to medium SAND, trace silt and SAND, trace silt, gravel with seam of orange-brown SAND, some gravel, trace silt. (GLACIAL OUTWASH) Compact stratified gray-brown and light gray SAND, trace silt, gravel and gravelly SAND, trace silt. (GLACIAL OUTWASH) NOTE: After sampling 10- 12 ft., removed Augers and replaced with NW casing to 15 ft. Then performed wet rotary drilling methods for remainder of Borehole. Compact to dense light gray-brown stratified SAND, trace silt and gravelly SAND, trace silt. (GLACIAL OUTWASH) Compact light gray-brown SAND, trace silt to orange-brown gravelly SAND, trace silt. (GLACIAL OUTWASH) PAVEMENT FILL GLACIAL OUTWASH Groundwater Observations NotesDepth 23.5 23.5 Elev. 12.0 12.0 Date 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.5 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-4 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-14-23 7-14-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-9 S-10 24/6 24/15 25.0-27.0 30.0-32.0 9 10 7 7 7 7 8 12 17 15 32.0 / 3.5 Compact light gray-brown SAND, some gravel, trace silt. (GLACIAL OUTWASH) NOTE: No reccovery on first attempt. Compact light gray-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) NOTE: No recovery on first and second attempt. GLACIAL OUTWASH Bottomof Borehole at 32.0 feet below existing grade. Groundwater Observations NotesDepth 23.5 23.5 Elev. 12.0 12.0 Date 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 2 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 12 11 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.5 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-4 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-14-23 7-14-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-1 S-2 S-2a S-3 S-4 S-5 S-6 S-7 18/16 6/4 18/16 24/18 24/20 24/20 24/20 24/20 0.5-2.0 2.0-2.5 2.5-4.0 4.0-6.0 6.0-8.0 10.0-12.0 15.0-17.0 20.0-22.0 1.1 0.3 0.1 0.1 0.1 0.1 5 5 3 6 10 12 18 16 18 28 26 24 20 27 21 3 4 11 15 5 6 7 12 5 8 11 14 8 12 22 46 47 15 13 19 0.3 / 34.9 9.5 / 25.7 Loose black silty SAND, some gravel with ash and cinders. (FILL) Loose black SILT and SAND, trace gravel with ash and cinders. (FILL) Compact yellow-brown SAND and GRAVEL, trace silt. (FILL) Dense yellow-brown SAND and GRAVEL, trace silt. (FILL) Dense yellow-brown SAND and GRAVEL, trace silt. (FILL) Compact light gray-brown fine to medium gravelly SAND, trace silt to mottled orange-brown and light gray-brown gravelly SAND, trace silt. (GLACIAL OUTWASH) Compact light gray-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Compact stratfied light gray-brown fine to medium SAND, trace silt and SAND, trace silt, gravel. (GLACIAL OUTWASH) PAVEMENT FILL GLACIAL OUTWASH Groundwater Observations NotesDepth 23.7 23.9 23.9 Elev. 11.5 11.3 11.3 Date 7-13-23 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.2 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-5 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 3.75" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-13-23 7-13-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-8 S-9 S-10 24/20 24/20 24/3 22.0-24.0 24.0-26.0 30.0-32.0 9 9 10 9 5 5 6 6 6 6 6 9 19 11 12 32.0 / 3.2 Compact light gray-brown fine to medium SAND, trace to some silt to SAND, trace sitl, gravel with seamof orange-brown SAND, trace silt gravel at ~ 23.5 ft. NOTE: Driller had only 20 ft. of Augers. Drove Split Spoon continous to 26 ft to dertemine top of ground water. Split Spoon wet at ~ 23 ft. Compact light gray-brown SAND, trace sitl, gravel. (GLACIAL OUTWASH) NOTE: After sampling to 26 ft. Removed Augers and replaced with NW casing to 30. Performed wet rotary drilling methods for remainder of Borehole. Compact light gray-brown SAND, some gravel. (GLACIAL OUTWASH) NOTE: No Recovery 1st attempt - gravel wedged in Split Spoon nose. GLACIAL OUTWASH Bottom of Borehole at 32.0 feet below existing grade. Groundwater Observations NotesDepth 23.7 23.9 23.9 Elev. 11.5 11.3 11.3 Date 7-13-23 7-14-23 7-17-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 2 of 2 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 12 11 10 9 8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 35.2 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 300 lbs./24 inches 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-5 (OW) GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 3.75" I.D. HSA/NW CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-13-23 7-13-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum S-1 S-2 S-3 S-4 S-5 S-6 18/13 24/18 24/15 24/16 24/8 24/20 0.5-2.0 2.0-4.0 4.0-6.0 6.0-8.0 10.0-12.0 15.0-17.0 0.1 0.1 0.1 0.1 0.1 0.1 7 20 14 15 17 20 26 28 39 49 63 23 25 24 25 20 18 18 21 10 13 15 15 34 37 88 49 36 28 0.2 / 33.9 6.0 / 28.1 17.0 / 17.1 Dense yellow-brown/brown SAND and GRAVEL, trace silt to dark gray-brown silty SAND, some gravel. (FILL) Dense yellow-brown/brown SAND and GRAVEL, trace silt, gravel. (FILL) Very dense yellow-brown/brown SAND and GRAVEL, trace silt, gravel. (FILL) Dense stratified yellow-brown and light gray-brown SAND, trace silt, gravel. (GLACIAL OUTWASH) Dense gray-brown and light gray-brown gravelly SAND, some silt. (GLACIAL OUTWASH) Compact stratified light gray-brown SAND, trace silt and SAND, some gravel, trace sitl. (GLACIAL OUTWASH) PAVEMENT FILL GLACIAL OUTWASH Bottom of Borehole at 17.0 feet below existing grade. Groundwater Observations NotesDepth NE Elev.Date 7-14-23 Job #: Date Started: Date Finished: Temperature: Total Volatile Organic Compounds (TVOC) measured w/ PID Model: Mini-Rae 3000 Notes:Notes: Project: Location: City/State: BLOWS/FT. 0-4 4-10 10-30 30-50 >50 BLOWS/FT. <2 2-4 4-8 8-15 15-30 >30 Page 1 of 1 T. M. Cormican Carr-Dee CorpContractor: Driller/Helper: Logged By/Reviewed By: Surface Elevation (ft): SOIL CONTAINING THREE COMPONENTS EACH OF WHICH COMPRISE AT LEAST 25% OF THE TOTAL ARE CLASSIFIED AS "A WELL-GRADED MIXTURE OF" Elev. (ft) 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 No.SymbolPen. /Rec. (in) Depth (ft) Depth (ft) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 TVOC (ppm) SOIL COMPONENT DESCRIPTIVE TERM "TRACE" "SOME" "ADJECTIVE" (eg SANDY, SILTY) "AND" PROPORTION OF TOTAL 0-10% 10-20% 20-35% 35-50% Blows/6" Min/ft N-Value RQD DENSITY V.LOOSE LOOSE COMPACT DENSE V.DENSE 1-3/8" I.D. Split Spoon 34.1 McPHAIL ASSOCIATES, LLC 2269 MASSACHUSETTS AVENUE CAMBRIDGE, MA 02140 TEL: 617-868-1420 FAX: 617-868-1423 NA 140 lbs./30 inches Used Automatic Hammer to drive Split Spoon B-6 GRANULAR SOILS COHESIVE SOILS G. Smith/C. Smith Notes: Sample Depth/EL toStrata Change(ft)Casing Type/Depth (ft): Casing Hammer (lbs)/Drop (in): Sampler Size/Type: Sampler Hammer (lbs)/Drop (in): 2.25" I.D. HSA CONSISTENCY V.SOFT SOFT FIRM STIFF V.STIFF HARD 7682.2.T1 7-14-23 7-14-23 307 Main Street 307 Main Street 307 Main Street TVOC Background: 0.0 ppm Weather: Variable Boring No. Sample Description and Boring NotesStratum APPENDIX C: GROUNDWATER MONITORING REPORTS Groundwater Monitoring Report Well I.D.:B-3 (OW)Road Box Elev.:+35.1 Project:307 Main Street Top of PVC Elev.:+34.7 Location:Hyannis, Massachusetts Top of Well Screen Elev.:+14.9 Project No.:7681.2.T1 Bot. of Well Screen Elev.:+4.9 Elev. Datum:NAVD88 (GEOID18)Well Diameter:2 inch I.D. Date Time Elapsed Time Depth from Road Box (feet) Groundwater Elev. (feet)McPhail Representative Comments 07/13/23 2:55 PM Initial 23.6 +11.5 T. M. Cormican Initial Reading - Before Well Developed 07/14/23 6:45 AM 1 Day(s)23.5 +11.6 T. M. Cormican Recent Precipitation Event 07/17/23 6:45 AM 4 Day(s)23.6 +11.5 T. M. Cormican Recent Precipitation Event Page 1 of 3 McPhail Associates, LLC Groundwater Monitoring Report Well I.D.:B-4 (OW)Road Box Elev.:+35.5 Project:307 Main Street Top of PVC Elev.:+35.4 Location:Hyannis, Massachusetts Top of Well Screen Elev.:+15.2 Project No.:7681.2.T1 Bot. of Well Screen Elev.:+5.2 Elev. Datum:NAVD88 (GEOID18)Well Diameter:2 inch I.D. Date Time Elapsed Time Depth from Road Box (feet) Groundwater Elev. (feet)McPhail Representative Comments 07/14/23 11:15 AM Initial 23.5 +12.0 T. M. Cormican Initial Reading - Before Well Developed 07/17/23 6:55 AM 3 Day(s)23.5 +12.0 T. M. Cormican Recent Precipitation Event Page 2 of 3 McPhail Associates, LLC Groundwater Monitoring Report Well I.D.:B-5 (OW)Road Box Elev.:+35.2 Project:307 Main Street Top of PVC Elev.:+35.0 Location:Hyannis, Massachusetts Top of Well Screen Elev.:+15.0 Project No.:7681.2.T1 Bot. of Well Screen Elev.:+5.0 Elev. Datum:NAVD88 (GEOID18)Well Diameter:2 inch I.D. Date Time Elapsed Time Depth from Road Box (feet) Groundwater Elev. (feet)McPhail Representative Comments 07/13/23 10:50 AM Initial 23.7 +11.5 T. M. Cormican Initial Reading - Before Well Developed 07/14/23 6:40 AM 1 Day(s)23.9 +11.3 T. M. Cormican Recent Precipitation Event 07/17/23 6:40 AM 4 Day(s)23.9 +11.3 T. M. Cormican Recent Precipitation Event Page 3 of 3 McPhail Associates, LLC Attachment 2 Pre-Development Hydrologic Analysis Existing Conditions Hydrology Calculation Summary Hyannis Multi-family Hyannis, Massachusetts 3447.00 Existing Conditions Hydrology Calculation Summary Objective To determine the pre-development peak rates of runoff from the site for the 2, 10, & 100 -year storm events at the design points. Conclusion Pre-Development Peak Runoff Rates (CFS) Storm Event DP-1 (Main Street) DP-2 (On-site Drainage System) 2-Year 0.16 3.80 10-Year 0.65 6.19 25-Year 1.11 8.03 100-Year 2.17 11.70 Calculation Methods 1. Runoff curve numbers (CN), time-of concentration (Tc), and runoff rates were calculated based on TR-55 methodology. 2. AutoCAD 2019 computer program was utilized for digitizing ground cover areas. 3. Peak runoff rates were computed using HydroCAD version 10.20. Assumptions 1. Ground cover types were determined using on-site visual observations and aerial imagery. 2. Hydrologic soil groups were based on United States Department of Agriculture, NRCS Soil Survey map information. 3. Stormwater runoff from off-site tributary areas was included in the calculation. 4. Due to the nature of the site, a minimum Tc of 6 minutes was chosen for all subcatchments. Sources of Data/ Equations 1. NRCS Web Soil Survey Hydrologic Soil Group – Barnstable County, Massachusetts, downloaded from Web Soil Survey on 6/15/2023. 2. NRCC Rainfall data for Barnstable County. 3. TR-55 Urban Hydrology for Small Watersheds, SCS, 1986. 4. Massachusetts DEP Stormwater Management Handbook, February 2008. List of Attachments 1. Existing Conditions Watershed Map prepared by Beals and Thomas, Inc. File No. 344700P001A. 2. HydroCAD – Routing Diagram for 344700HC001A. Existing Conditions Hydrology Calculation Summary Hyannis Multi-family Hyannis, Massachusetts REV CALC. BY DATE CHECKED BY DATE APPROVED BY DATE 0 NPS 7/17/2023 KJP 7/17/2023 344700CS001A Existing Conditions Hydrology Calculation Summary Attachment 1 Existing Conditions Watershed Map Figure1Hyannis Multi-familyHyannis, MassachusettsExisting ConditionsWatershed MapB+T Drawing No. 344700P001A-001Date: 07/17/2023 Scale: 1" = 50' B E A L S + T H O M A S Existing Conditions Hydrology Calculation Summary Attachment 2 Routing Diagram EDA-1A Subcat EDA-1A EDA-2A Subcat EDA-2A 1R Main Street 2R On-site Drainage System Routing Diagram for 344700HC001A Prepared by Beals & Thomas Inc, Printed 7/18/2023 HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Subcat Reach Pond Link 344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 2HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.537 39 >75% Grass cover, Good, HSG A (EDA-1A, EDA-2A) 0.008 96 Gravel surface, HSG A (EDA-1A, EDA-2A) 1.016 98 Paved parking, HSG A (EDA-1A, EDA-2A) 0.365 98 Roofs, HSG A (EDA-2A) 0.007 98 Unconnected pavement, HSG A (EDA-1A, EDA-2A) 1.933 82 TOTAL AREA NRCC 24-hr C 2-Year Rainfall=3.32"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 3HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=0.488 ac 33.18% Impervious Runoff Depth>0.42"Subcatchment EDA-1A: Subcat EDA-1A Tc=6.0 min CN=59 Runoff=0.16 cfs 0.017 af Runoff Area=1.445 ac 84.81% Impervious Runoff Depth>2.19"Subcatchment EDA-2A: Subcat EDA-2A Tc=6.0 min CN=89 Runoff=3.80 cfs 0.264 af Inflow=0.16 cfs 0.017 afReach 1R: Main Street Outflow=0.16 cfs 0.017 af Inflow=3.80 cfs 0.264 afReach 2R: On-site Drainage System Outflow=3.80 cfs 0.264 af Total Runoff Area = 1.933 ac Runoff Volume = 0.281 af Average Runoff Depth = 1.74" 28.22% Pervious = 0.546 ac 71.78% Impervious = 1.388 ac NRCC 24-hr C 2-Year Rainfall=3.32"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 4HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment EDA-1A: Subcat EDA-1A Runoff =0.16 cfs @ 12.16 hrs, Volume=0.017 af, Depth>0.42" Routed to Reach 1R : Main Street Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.32" Area (ac)CN Description 0.001 98 Unconnected pavement, HSG A 0.008 96 Gravel surface, HSG A 0.319 39 >75% Grass cover, Good, HSG A 0.161 98 Paved parking, HSG A 0.488 59 Weighted Average 0.326 66.82% Pervious Area 0.162 33.18% Impervious Area 0.001 0.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc Summary for Subcatchment EDA-2A: Subcat EDA-2A Runoff =3.80 cfs @ 12.13 hrs, Volume=0.264 af, Depth>2.19" Routed to Reach 2R : On-site Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.32" Area (ac)CN Description 0.365 98 Roofs, HSG A 0.006 98 Unconnected pavement, HSG A 0.001 96 Gravel surface, HSG A 0.219 39 >75% Grass cover, Good, HSG A 0.855 98 Paved parking, HSG A 1.445 89 Weighted Average 0.220 15.19% Pervious Area 1.226 84.81% Impervious Area 0.006 0.48% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc NRCC 24-hr C 2-Year Rainfall=3.32"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 5HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Reach 1R: Main Street [40] Hint: Not Described (Outflow=Inflow) Inflow Area =0.488 ac,33.18% Impervious, Inflow Depth > 0.42" for 2-Year event Inflow =0.16 cfs @ 12.16 hrs, Volume=0.017 af Outflow =0.16 cfs @ 12.16 hrs, Volume=0.017 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Reach 2R: On-site Drainage System [40] Hint: Not Described (Outflow=Inflow) Inflow Area =1.445 ac,84.81% Impervious, Inflow Depth > 2.19" for 2-Year event Inflow =3.80 cfs @ 12.13 hrs, Volume=0.264 af Outflow =3.80 cfs @ 12.13 hrs, Volume=0.264 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.89"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 6HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=0.488 ac 33.18% Impervious Runoff Depth>1.17"Subcatchment EDA-1A: Subcat EDA-1A Tc=6.0 min CN=59 Runoff=0.65 cfs 0.048 af Runoff Area=1.445 ac 84.81% Impervious Runoff Depth>3.66"Subcatchment EDA-2A: Subcat EDA-2A Tc=6.0 min CN=89 Runoff=6.19 cfs 0.441 af Inflow=0.65 cfs 0.048 afReach 1R: Main Street Outflow=0.65 cfs 0.048 af Inflow=6.19 cfs 0.441 afReach 2R: On-site Drainage System Outflow=6.19 cfs 0.441 af Total Runoff Area = 1.933 ac Runoff Volume = 0.489 af Average Runoff Depth = 3.03" 28.22% Pervious = 0.546 ac 71.78% Impervious = 1.388 ac NRCC 24-hr C 10-Year Rainfall=4.89"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 7HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment EDA-1A: Subcat EDA-1A Runoff =0.65 cfs @ 12.14 hrs, Volume=0.048 af, Depth>1.17" Routed to Reach 1R : Main Street Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.89" Area (ac)CN Description 0.001 98 Unconnected pavement, HSG A 0.008 96 Gravel surface, HSG A 0.319 39 >75% Grass cover, Good, HSG A 0.161 98 Paved parking, HSG A 0.488 59 Weighted Average 0.326 66.82% Pervious Area 0.162 33.18% Impervious Area 0.001 0.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc Summary for Subcatchment EDA-2A: Subcat EDA-2A Runoff =6.19 cfs @ 12.13 hrs, Volume=0.441 af, Depth>3.66" Routed to Reach 2R : On-site Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.89" Area (ac)CN Description 0.365 98 Roofs, HSG A 0.006 98 Unconnected pavement, HSG A 0.001 96 Gravel surface, HSG A 0.219 39 >75% Grass cover, Good, HSG A 0.855 98 Paved parking, HSG A 1.445 89 Weighted Average 0.220 15.19% Pervious Area 1.226 84.81% Impervious Area 0.006 0.48% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc NRCC 24-hr C 10-Year Rainfall=4.89"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 8HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Reach 1R: Main Street [40] Hint: Not Described (Outflow=Inflow) Inflow Area =0.488 ac,33.18% Impervious, Inflow Depth > 1.17" for 10-Year event Inflow =0.65 cfs @ 12.14 hrs, Volume=0.048 af Outflow =0.65 cfs @ 12.14 hrs, Volume=0.048 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Reach 2R: On-site Drainage System [40] Hint: Not Described (Outflow=Inflow) Inflow Area =1.445 ac,84.81% Impervious, Inflow Depth > 3.66" for 10-Year event Inflow =6.19 cfs @ 12.13 hrs, Volume=0.441 af Outflow =6.19 cfs @ 12.13 hrs, Volume=0.441 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=6.10"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 9HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=0.488 ac 33.18% Impervious Runoff Depth>1.90"Subcatchment EDA-1A: Subcat EDA-1A Tc=6.0 min CN=59 Runoff=1.11 cfs 0.077 af Runoff Area=1.445 ac 84.81% Impervious Runoff Depth>4.83"Subcatchment EDA-2A: Subcat EDA-2A Tc=6.0 min CN=89 Runoff=8.03 cfs 0.582 af Inflow=1.11 cfs 0.077 afReach 1R: Main Street Outflow=1.11 cfs 0.077 af Inflow=8.03 cfs 0.582 afReach 2R: On-site Drainage System Outflow=8.03 cfs 0.582 af Total Runoff Area = 1.933 ac Runoff Volume = 0.659 af Average Runoff Depth = 4.09" 28.22% Pervious = 0.546 ac 71.78% Impervious = 1.388 ac NRCC 24-hr C 25-Year Rainfall=6.10"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 10HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment EDA-1A: Subcat EDA-1A Runoff =1.11 cfs @ 12.14 hrs, Volume=0.077 af, Depth>1.90" Routed to Reach 1R : Main Street Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=6.10" Area (ac)CN Description 0.001 98 Unconnected pavement, HSG A 0.008 96 Gravel surface, HSG A 0.319 39 >75% Grass cover, Good, HSG A 0.161 98 Paved parking, HSG A 0.488 59 Weighted Average 0.326 66.82% Pervious Area 0.162 33.18% Impervious Area 0.001 0.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc Summary for Subcatchment EDA-2A: Subcat EDA-2A Runoff =8.03 cfs @ 12.13 hrs, Volume=0.582 af, Depth>4.83" Routed to Reach 2R : On-site Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=6.10" Area (ac)CN Description 0.365 98 Roofs, HSG A 0.006 98 Unconnected pavement, HSG A 0.001 96 Gravel surface, HSG A 0.219 39 >75% Grass cover, Good, HSG A 0.855 98 Paved parking, HSG A 1.445 89 Weighted Average 0.220 15.19% Pervious Area 1.226 84.81% Impervious Area 0.006 0.48% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc NRCC 24-hr C 25-Year Rainfall=6.10"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 11HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Reach 1R: Main Street [40] Hint: Not Described (Outflow=Inflow) Inflow Area =0.488 ac,33.18% Impervious, Inflow Depth > 1.90" for 25-Year event Inflow =1.11 cfs @ 12.14 hrs, Volume=0.077 af Outflow =1.11 cfs @ 12.14 hrs, Volume=0.077 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Reach 2R: On-site Drainage System [40] Hint: Not Described (Outflow=Inflow) Inflow Area =1.445 ac,84.81% Impervious, Inflow Depth > 4.83" for 25-Year event Inflow =8.03 cfs @ 12.13 hrs, Volume=0.582 af Outflow =8.03 cfs @ 12.13 hrs, Volume=0.582 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 12HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=0.488 ac 33.18% Impervious Runoff Depth>3.63"Subcatchment EDA-1A: Subcat EDA-1A Tc=6.0 min CN=59 Runoff=2.17 cfs 0.148 af Runoff Area=1.445 ac 84.81% Impervious Runoff Depth>7.22"Subcatchment EDA-2A: Subcat EDA-2A Tc=6.0 min CN=89 Runoff=11.70 cfs 0.870 af Inflow=2.17 cfs 0.148 afReach 1R: Main Street Outflow=2.17 cfs 0.148 af Inflow=11.70 cfs 0.870 afReach 2R: On-site Drainage System Outflow=11.70 cfs 0.870 af Total Runoff Area = 1.933 ac Runoff Volume = 1.017 af Average Runoff Depth = 6.31" 28.22% Pervious = 0.546 ac 71.78% Impervious = 1.388 ac NRCC 24-hr C 100-Year Rainfall=8.55"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 13HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment EDA-1A: Subcat EDA-1A Runoff =2.17 cfs @ 12.13 hrs, Volume=0.148 af, Depth>3.63" Routed to Reach 1R : Main Street Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Area (ac)CN Description 0.001 98 Unconnected pavement, HSG A 0.008 96 Gravel surface, HSG A 0.319 39 >75% Grass cover, Good, HSG A 0.161 98 Paved parking, HSG A 0.488 59 Weighted Average 0.326 66.82% Pervious Area 0.162 33.18% Impervious Area 0.001 0.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc Summary for Subcatchment EDA-2A: Subcat EDA-2A Runoff =11.70 cfs @ 12.13 hrs, Volume=0.870 af, Depth>7.22" Routed to Reach 2R : On-site Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Area (ac)CN Description 0.365 98 Roofs, HSG A 0.006 98 Unconnected pavement, HSG A 0.001 96 Gravel surface, HSG A 0.219 39 >75% Grass cover, Good, HSG A 0.855 98 Paved parking, HSG A 1.445 89 Weighted Average 0.220 15.19% Pervious Area 1.226 84.81% Impervious Area 0.006 0.48% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Minimum Tc NRCC 24-hr C 100-Year Rainfall=8.55"344700HC001A Printed 7/18/2023Prepared by Beals & Thomas Inc Page 14HydroCAD® 10.20-2g s/n 04493 © 2022 HydroCAD Software Solutions LLC Summary for Reach 1R: Main Street [40] Hint: Not Described (Outflow=Inflow) Inflow Area =0.488 ac,33.18% Impervious, Inflow Depth > 3.63" for 100-Year event Inflow =2.17 cfs @ 12.13 hrs, Volume=0.148 af Outflow =2.17 cfs @ 12.13 hrs, Volume=0.148 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Reach 2R: On-site Drainage System [40] Hint: Not Described (Outflow=Inflow) Inflow Area =1.445 ac,84.81% Impervious, Inflow Depth > 7.22" for 100-Year event Inflow =11.70 cfs @ 12.13 hrs, Volume=0.870 af Outflow =11.70 cfs @ 12.13 hrs, Volume=0.870 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Attachment 3 Post-Development Hydrologic Analysis Calculation Summary 307 Main Street Hyannis, Massachusetts 3447.00 Proposed Hydrology Calculation Summary Objective 1. To demonstrate that the post-development stormwater runoff rates and runoff volumes will be less than or equal to the existing runoff rates and runoff volumes. 2. To demonstrate that the project will infiltrate the 25-year storm on site. Conclusion Table 1: Pre- & Post-development Peak Runoff Rate Comparison, units are in cubic feet per second (cfs). Storm Event Design Point 1: Main Street Design Point 2: On-Site System Pre Post Pre Post 2-Year 0.16 0.15 3.80 0.00 10-Year 0.65 0.37 6.19 0.00 25-Year 1.11 0.56 8.03 0.00 100-Year 2.17 0.97 11.70 0.00 Table 2: Pre- & Post-development Runoff Volume Comparison, units are in acre-feet. Storm Event Design Point 1: Main Street Design Point 2: On-Site System Pre Post Pre Post 2-Year 0.02 0.01 0.26 0.00 10-Year 0.05 0.03 0.44 0.00 25-Year 0.08 0.04 0.58 0.00 100-Year 0.15 0.07 0.87 0.00 Calculation Methods 1. Runoff curve numbers (CN), time-of concentration (Tc), and runoff rates were calculated based on TR-55 methodology. 2. AutoCAD 2019 computer program was utilized for digitizing ground cover areas. 3. Peak runoff rates were computed using HydroCAD version 10.20. Assumptions 1. Ground cover types were determined using on-site visual observations and aerial imagery. 2. Hydrologic soil groups were based on United States Department of Agriculture, NRCS Soil Survey map information. Soils are classified as Hydrologic Soil Group A. 3. Stormwater runoff from off-site tributary areas was included in the calculation. 4. Due to the nature of the site, a minimum Tc of 6 minutes was chosen for all subcatchments. 5. The exfiltration rate is 8.27 in/hour or 2.41 in/hr based on recommendations from the geotechnical engineer. Calculation Summary 307 Main Street Hyannis, Massachusetts Sources of Data/ Equations 1. “Existing Conditions Hydrology Calculation Summary” prepared by Beals and Thomas, dated July 22, 2023 (344700CS001A.pdf). 2. NRCS Web Soil Survey Hydrologic Soil Group – Barnstable County, Massachusetts, downloaded from Web Soil Survey on 6/15/2023. 3. NRCC Rainfall data for Barnstable County. 4. TR-55 Urban Hydrology for Small Watersheds, SCS, 1986. 5. Massachusetts DEP Stormwater Management Handbook, February 2008. 6. “Foundation Engineering Report- 307 Main Street” prepared by McPhail Associates, LLC and dated August 22, 2023. The report includes infiltration rates. List of Attachments 1. Proposed Conditions Hydrology Map and HydroCAD Model Reports 2. Infiltration of the 25-Year Storm REV CALC. BY DATE CHECKED BY DATE APPROVED BY DATE 0 K. Pritchard 04/04/2024 344700CS004A.docx PAT 04/05/2024 P. Thompson 04/11/2024 Calculation Summary 307 Main Street Hyannis, Massachusetts Attachment 1 Proposed Conditions Hydrology Figure2Watershed Map307 Main StreetHyannis, MassachusettsB+T Drawing No. 344700P018A-001Date: 04/04/2024 Scale: 1" = 50'Proposed Conditions Hydrology(NO HATCH)MAIN STREETO L D C O L O N Y R O A D PDA-1A Subcat PDA-1A PDA-2A Subcat PDA-2A PDA-2B Subcat PDA-2B PDA-2C Subcat PDA-2C 1R Main Street 4R On-site Stormwater Management System 1P Subsurface Infiltration System-1 2P Subsurface Infiltration System-2 3P Subsurface Infiltration System-3 Routing Diagram for 344700HC003A-definitive Prepared by Beals & Thomas Inc, Printed 4/4/2024 HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link Post-DevelopmentG:\Projdata\3447\Eng\ 344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 2HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.762 39 >75% Grass cover, Good, HSG A (PDA-1A, PDA-2A, PDA-2B, PDA-2C) 0.028 30 Brush, Good, HSG A (PDA-2C) 0.075 30 Meadow, non-grazed, HSG A (PDA-1A) 0.629 98 Paved parking, HSG A (PDA-1A, PDA-2A, PDA-2B, PDA-2C) 0.442 98 Roofs, HSG A (PDA-2C) 1.937 71 TOTAL AREA Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 2-Year Rainfall=3.32"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 3HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=7,363 sf 55.54% Impervious Runoff Depth>0.80"Subcatchment PDA-1A: Subcat PDA-1A Tc=6.0 min CN=68 Runoff=0.15 cfs 0.011 af Runoff Area=7,930 sf 89.35% Impervious Runoff Depth>2.46"Subcatchment PDA-2A: Subcat PDA-2A Tc=6.0 min CN=92 Runoff=0.53 cfs 0.037 af Runoff Area=6,304 sf 93.99% Impervious Runoff Depth>2.66"Subcatchment PDA-2B: Subcat PDA-2B Tc=6.0 min CN=94 Runoff=0.44 cfs 0.032 af Runoff Area=1.441 ac 47.11% Impervious Runoff Depth>0.75"Subcatchment PDA-2C: Subcat PDA-2C Tc=6.0 min CN=67 Runoff=1.20 cfs 0.090 af Inflow=0.15 cfs 0.011 afReach 1R: Main Street Outflow=0.15 cfs 0.011 af Inflow=0.00 cfs 0.000 afReach 4R: On-site Stormwater Management System Outflow=0.00 cfs 0.000 af Peak Elev=20.33' Storage=0.014 af Inflow=0.53 cfs 0.037 afPond 1P: Subsurface Infiltration System-1 Discarded=0.04 cfs 0.037 af Primary=0.00 cfs 0.000 af Outflow=0.04 cfs 0.037 af Peak Elev=24.58' Storage=0.007 af Inflow=0.44 cfs 0.032 afPond 2P: Subsurface Infiltration System-2 Discarded=0.08 cfs 0.032 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.032 af Peak Elev=25.53' Storage=0.020 af Inflow=1.20 cfs 0.090 afPond 3P: Subsurface Infiltration System-3 Discarded=0.23 cfs 0.090 af Primary=0.00 cfs 0.000 af Outflow=0.23 cfs 0.090 af Total Runoff Area = 1.937 ac Runoff Volume = 0.171 af Average Runoff Depth = 1.06" 44.68% Pervious = 0.865 ac 55.32% Impervious = 1.071 ac Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 10-Year Rainfall=4.89"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 9HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=7,363 sf 55.54% Impervious Runoff Depth>1.80"Subcatchment PDA-1A: Subcat PDA-1A Tc=6.0 min CN=68 Runoff=0.37 cfs 0.025 af Runoff Area=7,930 sf 89.35% Impervious Runoff Depth>3.98"Subcatchment PDA-2A: Subcat PDA-2A Tc=6.0 min CN=92 Runoff=0.82 cfs 0.060 af Runoff Area=6,304 sf 93.99% Impervious Runoff Depth>4.20"Subcatchment PDA-2B: Subcat PDA-2B Tc=6.0 min CN=94 Runoff=0.68 cfs 0.051 af Runoff Area=1.441 ac 47.11% Impervious Runoff Depth>1.72"Subcatchment PDA-2C: Subcat PDA-2C Tc=6.0 min CN=67 Runoff=3.01 cfs 0.207 af Inflow=0.37 cfs 0.025 afReach 1R: Main Street Outflow=0.37 cfs 0.025 af Inflow=0.00 cfs 0.000 afReach 4R: On-site Stormwater Management System Outflow=0.00 cfs 0.000 af Peak Elev=21.24' Storage=0.027 af Inflow=0.82 cfs 0.060 afPond 1P: Subsurface Infiltration System-1 Discarded=0.04 cfs 0.055 af Primary=0.00 cfs 0.000 af Outflow=0.04 cfs 0.055 af Peak Elev=25.59' Storage=0.015 af Inflow=0.68 cfs 0.051 afPond 2P: Subsurface Infiltration System-2 Discarded=0.08 cfs 0.051 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.051 af Peak Elev=26.45' Storage=0.081 af Inflow=3.01 cfs 0.207 afPond 3P: Subsurface Infiltration System-3 Discarded=0.23 cfs 0.206 af Primary=0.00 cfs 0.000 af Outflow=0.23 cfs 0.206 af Total Runoff Area = 1.937 ac Runoff Volume = 0.343 af Average Runoff Depth = 2.13" 44.68% Pervious = 0.865 ac 55.32% Impervious = 1.071 ac Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 25-Year Rainfall=6.10"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 15HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=7,363 sf 55.54% Impervious Runoff Depth>2.69"Subcatchment PDA-1A: Subcat PDA-1A Tc=6.0 min CN=68 Runoff=0.56 cfs 0.038 af Runoff Area=7,930 sf 89.35% Impervious Runoff Depth>5.16"Subcatchment PDA-2A: Subcat PDA-2A Tc=6.0 min CN=92 Runoff=1.05 cfs 0.078 af Runoff Area=6,304 sf 93.99% Impervious Runoff Depth>5.39"Subcatchment PDA-2B: Subcat PDA-2B Tc=6.0 min CN=94 Runoff=0.85 cfs 0.065 af Runoff Area=1.441 ac 47.11% Impervious Runoff Depth>2.60"Subcatchment PDA-2C: Subcat PDA-2C Tc=6.0 min CN=67 Runoff=4.60 cfs 0.312 af Inflow=0.56 cfs 0.038 afReach 1R: Main Street Outflow=0.56 cfs 0.038 af Inflow=0.00 cfs 0.000 afReach 4R: On-site Stormwater Management System Outflow=0.00 cfs 0.000 af Peak Elev=22.06' Storage=0.038 af Inflow=1.05 cfs 0.078 afPond 1P: Subsurface Infiltration System-1 Discarded=0.04 cfs 0.058 af Primary=0.00 cfs 0.000 af Outflow=0.04 cfs 0.058 af Peak Elev=26.53' Storage=0.021 af Inflow=0.85 cfs 0.065 afPond 2P: Subsurface Infiltration System-2 Discarded=0.08 cfs 0.065 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.065 af Peak Elev=27.37' Storage=0.149 af Inflow=4.60 cfs 0.312 afPond 3P: Subsurface Infiltration System-3 Discarded=0.23 cfs 0.246 af Primary=0.00 cfs 0.000 af Outflow=0.23 cfs 0.246 af Total Runoff Area = 1.937 ac Runoff Volume = 0.494 af Average Runoff Depth = 3.06" 44.68% Pervious = 0.865 ac 55.32% Impervious = 1.071 ac Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 21HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=7,363 sf 55.54% Impervious Runoff Depth>4.70"Subcatchment PDA-1A: Subcat PDA-1A Tc=6.0 min CN=68 Runoff=0.97 cfs 0.066 af Runoff Area=7,930 sf 89.35% Impervious Runoff Depth>7.58"Subcatchment PDA-2A: Subcat PDA-2A Tc=6.0 min CN=92 Runoff=1.51 cfs 0.115 af Runoff Area=6,304 sf 93.99% Impervious Runoff Depth>7.82"Subcatchment PDA-2B: Subcat PDA-2B Tc=6.0 min CN=94 Runoff=1.21 cfs 0.094 af Runoff Area=1.441 ac 47.11% Impervious Runoff Depth>4.58"Subcatchment PDA-2C: Subcat PDA-2C Tc=6.0 min CN=67 Runoff=8.09 cfs 0.550 af Inflow=0.97 cfs 0.066 afReach 1R: Main Street Outflow=0.97 cfs 0.066 af Inflow=0.00 cfs 0.000 afReach 4R: On-site Stormwater Management System Outflow=0.00 cfs 0.000 af Peak Elev=24.18' Storage=0.063 af Inflow=1.51 cfs 0.115 afPond 1P: Subsurface Infiltration System-1 Discarded=0.04 cfs 0.064 af Primary=0.00 cfs 0.000 af Outflow=0.04 cfs 0.064 af Peak Elev=29.31' Storage=0.036 af Inflow=1.21 cfs 0.094 afPond 2P: Subsurface Infiltration System-2 Discarded=0.08 cfs 0.094 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.094 af Peak Elev=30.10' Storage=0.323 af Inflow=8.09 cfs 0.550 afPond 3P: Subsurface Infiltration System-3 Discarded=0.23 cfs 0.266 af Primary=0.00 cfs 0.000 af Outflow=0.23 cfs 0.266 af Total Runoff Area = 1.937 ac Runoff Volume = 0.825 af Average Runoff Depth = 5.11" 44.68% Pervious = 0.865 ac 55.32% Impervious = 1.071 ac Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 22HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PDA-1A: Subcat PDA-1A Runoff =0.97 cfs @ 12.13 hrs, Volume=0.066 af, Depth>4.70" Routed to Reach 1R : Main Street Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Area (sf)CN Description 1 39 >75% Grass cover, Good, HSG A 3,273 30 Meadow, non-grazed, HSG A 4,089 98 Paved parking, HSG A 7,363 68 Weighted Average 3,274 44.46% Pervious Area 4,089 55.54% Impervious Area Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Summary for Subcatchment PDA-2A: Subcat PDA-2A Runoff =1.51 cfs @ 12.13 hrs, Volume=0.115 af, Depth>7.58" Routed to Pond 1P : Subsurface Infiltration System-1 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Area (sf)CN Description 845 39 >75% Grass cover, Good, HSG A 7,086 98 Paved parking, HSG A 7,930 92 Weighted Average 845 10.65% Pervious Area 7,086 89.35% Impervious Area Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Summary for Subcatchment PDA-2B: Subcat PDA-2B Runoff =1.21 cfs @ 12.13 hrs, Volume=0.094 af, Depth>7.82" Routed to Pond 2P : Subsurface Infiltration System-2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 23HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Area (sf)CN Description 379 39 >75% Grass cover, Good, HSG A 5,925 98 Paved parking, HSG A 6,304 94 Weighted Average 379 6.01% Pervious Area 5,925 93.99% Impervious Area Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Summary for Subcatchment PDA-2C: Subcat PDA-2C Runoff =8.09 cfs @ 12.13 hrs, Volume=0.550 af, Depth>4.58" Routed to Pond 3P : Subsurface Infiltration System-3 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=8.55" Area (ac)CN Description 0.734 39 >75% Grass cover, Good, HSG A 0.028 30 Brush, Good, HSG A 0.237 98 Paved parking, HSG A 0.442 98 Roofs, HSG A 1.441 67 Weighted Average 0.762 52.89% Pervious Area 0.679 47.11% Impervious Area Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 6.0 Direct Entry, Summary for Reach 1R: Main Street [40] Hint: Not Described (Outflow=Inflow) Inflow Area =0.169 ac,55.54% Impervious, Inflow Depth > 4.70" for 100-Year event Inflow =0.97 cfs @ 12.13 hrs, Volume=0.066 af Outflow =0.97 cfs @ 12.13 hrs, Volume=0.066 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Reach 4R: On-site Stormwater Management System [40] Hint: Not Described (Outflow=Inflow) Inflow Area =1.768 ac,55.30% Impervious, Inflow Depth = 0.00" for 100-Year event Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Outflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 24HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Pond 1P: Subsurface Infiltration System-1 Inflow Area =0.182 ac,89.35% Impervious, Inflow Depth > 7.58" for 100-Year event Inflow =1.51 cfs @ 12.13 hrs, Volume=0.115 af Outflow =0.04 cfs @ 9.40 hrs, Volume=0.064 af, Atten= 97%, Lag= 0.0 min Discarded =0.04 cfs @ 9.40 hrs, Volume=0.064 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 24.18' @ 15.67 hrs Surf.Area= 0.018 ac Storage= 0.063 af Plug-Flow detention time= 255.9 min calculated for 0.064 af (56% of inflow) Center-of-Mass det. time= 133.4 min ( 903.2 - 769.8 ) Volume Invert Avail.Storage Storage Description #1A 19.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field A 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #2A 19.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf 0.075 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 19.00'2.410 in/hr Exfiltration over Surface area #2 Primary 25.25'24.0" x 24.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.04 cfs @ 9.40 hrs HW=19.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.04 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=19.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 2P: Subsurface Infiltration System-2 Inflow Area =0.145 ac,93.99% Impervious, Inflow Depth > 7.82" for 100-Year event Inflow =1.21 cfs @ 12.13 hrs, Volume=0.094 af Outflow =0.08 cfs @ 10.90 hrs, Volume=0.094 af, Atten= 93%, Lag= 0.0 min Discarded =0.08 cfs @ 10.90 hrs, Volume=0.094 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 29.31' @ 13.44 hrs Surf.Area= 0.010 ac Storage= 0.036 af Plug-Flow detention time= 147.7 min calculated for 0.094 af (100% of inflow) Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 25HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Center-of-Mass det. time= 147.4 min ( 909.0 - 761.6 ) Volume Invert Avail.Storage Storage Description #1A 23.25'0.017 af 10.33'W x 40.42'L x 6.75'H Field A 0.065 af Overall - 0.022 af Embedded = 0.043 af x 40.0% Voids #2A 24.00'0.022 af ADS_StormTech MC-7200 +Cap x 5 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap Cap Storage= 39.5 cf x 2 x 1 rows = 79.0 cf 0.039 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 23.25'8.270 in/hr Exfiltration over Surface area #2 Primary 29.75'24.0" x 24.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.08 cfs @ 10.90 hrs HW=23.32' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=23.25' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 3P: Subsurface Infiltration System-3 Inflow Area =1.441 ac,47.11% Impervious, Inflow Depth > 4.58" for 100-Year event Inflow =8.09 cfs @ 12.13 hrs, Volume=0.550 af Outflow =0.23 cfs @ 10.80 hrs, Volume=0.266 af, Atten= 97%, Lag= 0.0 min Discarded =0.23 cfs @ 10.80 hrs, Volume=0.266 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 30.10' @ 17.06 hrs Surf.Area= 0.093 ac Storage= 0.323 af Plug-Flow detention time= 304.1 min calculated for 0.266 af (48% of inflow) Center-of-Mass det. time= 175.9 min ( 1,013.0 - 837.1 ) Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 26HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1A 25.00'0.036 af 19.42'W x 47.02'L x 6.75'H Field A 0.141 af Overall - 0.052 af Embedded = 0.089 af x 40.0% Voids #2A 25.75'0.052 af ADS_StormTech MC-7200 +Cap x 12 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 12 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #3B 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field B 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #4B 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #3 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #5C 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field C 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #6C 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #5 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #7D 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field D 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #8D 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #7 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #9E 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field E 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #10E 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #9 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf 0.388 af Total Available Storage Storage Group A created with Chamber Wizard Storage Group B created with Chamber Wizard Storage Group C created with Chamber Wizard Storage Group D created with Chamber Wizard Storage Group E created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 25.00'2.410 in/hr Exfiltration over Horizontal area #2 Primary 31.50'2.0" x 2.0" Horiz. Orifice/Grate X 7.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (29% open area) Discarded OutFlow Max=0.23 cfs @ 10.80 hrs HW=25.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.23 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=25.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) 3447.00 Proposed Hydrology Calculation Summary Attachment 2 Infiltration of the 25-Year Storm Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 25-Year Rainfall=6.10"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 15HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 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=7,363 sf 55.54% Impervious Runoff Depth>2.69"Subcatchment PDA-1A: Subcat PDA-1A Tc=6.0 min CN=68 Runoff=0.56 cfs 0.038 af Runoff Area=7,930 sf 89.35% Impervious Runoff Depth>5.16"Subcatchment PDA-2A: Subcat PDA-2A Tc=6.0 min CN=92 Runoff=1.05 cfs 0.078 af Runoff Area=6,304 sf 93.99% Impervious Runoff Depth>5.39"Subcatchment PDA-2B: Subcat PDA-2B Tc=6.0 min CN=94 Runoff=0.85 cfs 0.065 af Runoff Area=1.441 ac 47.11% Impervious Runoff Depth>2.60"Subcatchment PDA-2C: Subcat PDA-2C Tc=6.0 min CN=67 Runoff=4.60 cfs 0.312 af Inflow=0.56 cfs 0.038 afReach 1R: Main Street Outflow=0.56 cfs 0.038 af Inflow=0.00 cfs 0.000 afReach 4R: On-site Stormwater Management System Outflow=0.00 cfs 0.000 af Peak Elev=22.06' Storage=0.038 af Inflow=1.05 cfs 0.078 afPond 1P: Subsurface Infiltration System-1 Discarded=0.04 cfs 0.058 af Primary=0.00 cfs 0.000 af Outflow=0.04 cfs 0.058 af Peak Elev=26.53' Storage=0.021 af Inflow=0.85 cfs 0.065 afPond 2P: Subsurface Infiltration System-2 Discarded=0.08 cfs 0.065 af Primary=0.00 cfs 0.000 af Outflow=0.08 cfs 0.065 af Peak Elev=27.37' Storage=0.149 af Inflow=4.60 cfs 0.312 afPond 3P: Subsurface Infiltration System-3 Discarded=0.23 cfs 0.246 af Primary=0.00 cfs 0.000 af Outflow=0.23 cfs 0.246 af Total Runoff Area = 1.937 ac Runoff Volume = 0.494 af Average Runoff Depth = 3.06" 44.68% Pervious = 0.865 ac 55.32% Impervious = 1.071 ac Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 24HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Summary for Pond 1P: Subsurface Infiltration System-1 Inflow Area =0.182 ac,89.35% Impervious, Inflow Depth > 7.58" for 100-Year event Inflow =1.51 cfs @ 12.13 hrs, Volume=0.115 af Outflow =0.04 cfs @ 9.40 hrs, Volume=0.064 af, Atten= 97%, Lag= 0.0 min Discarded =0.04 cfs @ 9.40 hrs, Volume=0.064 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 24.18' @ 15.67 hrs Surf.Area= 0.018 ac Storage= 0.063 af Plug-Flow detention time= 255.9 min calculated for 0.064 af (56% of inflow) Center-of-Mass det. time= 133.4 min ( 903.2 - 769.8 ) Volume Invert Avail.Storage Storage Description #1A 19.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field A 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #2A 19.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf 0.075 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 19.00'2.410 in/hr Exfiltration over Surface area #2 Primary 25.25'24.0" x 24.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.04 cfs @ 9.40 hrs HW=19.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.04 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=19.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 2P: Subsurface Infiltration System-2 Inflow Area =0.145 ac,93.99% Impervious, Inflow Depth > 7.82" for 100-Year event Inflow =1.21 cfs @ 12.13 hrs, Volume=0.094 af Outflow =0.08 cfs @ 10.90 hrs, Volume=0.094 af, Atten= 93%, Lag= 0.0 min Discarded =0.08 cfs @ 10.90 hrs, Volume=0.094 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 29.31' @ 13.44 hrs Surf.Area= 0.010 ac Storage= 0.036 af Plug-Flow detention time= 147.7 min calculated for 0.094 af (100% of inflow) Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 25HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Center-of-Mass det. time= 147.4 min ( 909.0 - 761.6 ) Volume Invert Avail.Storage Storage Description #1A 23.25'0.017 af 10.33'W x 40.42'L x 6.75'H Field A 0.065 af Overall - 0.022 af Embedded = 0.043 af x 40.0% Voids #2A 24.00'0.022 af ADS_StormTech MC-7200 +Cap x 5 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap Cap Storage= 39.5 cf x 2 x 1 rows = 79.0 cf 0.039 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 23.25'8.270 in/hr Exfiltration over Surface area #2 Primary 29.75'24.0" x 24.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.08 cfs @ 10.90 hrs HW=23.32' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=23.25' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond 3P: Subsurface Infiltration System-3 Inflow Area =1.441 ac,47.11% Impervious, Inflow Depth > 4.58" for 100-Year event Inflow =8.09 cfs @ 12.13 hrs, Volume=0.550 af Outflow =0.23 cfs @ 10.80 hrs, Volume=0.266 af, Atten= 97%, Lag= 0.0 min Discarded =0.23 cfs @ 10.80 hrs, Volume=0.266 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routed to Reach 4R : On-site Stormwater Management System Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 30.10' @ 17.06 hrs Surf.Area= 0.093 ac Storage= 0.323 af Plug-Flow detention time= 304.1 min calculated for 0.266 af (48% of inflow) Center-of-Mass det. time= 175.9 min ( 1,013.0 - 837.1 ) Post-DevelopmentG:\Projdata\3447\Eng\ NRCC 24-hr C 100-Year Rainfall=8.55"344700HC003A-definitive Printed 4/4/2024Prepared by Beals & Thomas Inc Page 26HydroCAD® 10.20-4a s/n 04493 © 2023 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1A 25.00'0.036 af 19.42'W x 47.02'L x 6.75'H Field A 0.141 af Overall - 0.052 af Embedded = 0.089 af x 40.0% Voids #2A 25.75'0.052 af ADS_StormTech MC-7200 +Cap x 12 Inside #1 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 12 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #3B 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field B 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #4B 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #3 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #5C 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field C 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #6C 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #5 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #7D 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field D 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #8D 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #7 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf #9E 25.00'0.031 af 19.42'W x 40.42'L x 6.75'H Field E 0.122 af Overall - 0.044 af Embedded = 0.078 af x 40.0% Voids #10E 25.75'0.044 af ADS_StormTech MC-7200 +Cap x 10 Inside #9 Effective Size= 91.2"W x 60.0"H => 26.68 sf x 6.59'L = 175.9 cf Overall Size= 100.0"W x 60.0"H x 6.95'L with 0.36' Overlap 10 Chambers in 2 Rows Cap Storage= 39.5 cf x 2 x 2 rows = 158.0 cf 0.388 af Total Available Storage Storage Group A created with Chamber Wizard Storage Group B created with Chamber Wizard Storage Group C created with Chamber Wizard Storage Group D created with Chamber Wizard Storage Group E created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 25.00'2.410 in/hr Exfiltration over Horizontal area #2 Primary 31.50'2.0" x 2.0" Horiz. Orifice/Grate X 7.00 columns X 6 rows C= 0.600 in 24.0" x 24.0" Grate (29% open area) Discarded OutFlow Max=0.23 cfs @ 10.80 hrs HW=25.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.23 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=25.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) Attachment 4 Hydraulic Calculations Calculation Summary 307 Main Street Hyannis, Massachusetts 3447.00 Proposed Hydraulics Calculation Summary Objective 1. To design a stormwater collection system to capture and convey stormwater runoff under proposed conditions. Conclusion 1. The proposed stormwater collection system will adequately collect and convey stormwater runoff from the 50-year storm event. 2. The hydraulic grade lines from the proposed stormwater collection system do not exceed the proposed rim elevations. 3. Pipe velocities are greater than 3 fps and less than 10 fps, in compliance with the Barnstable Ordinance. 4. Pipes are sized to have capacities 25% greater than the model requires. Calculation Methods 1. Pipes, structures, and catchment areas were modeled in StormCAD. 2. To be conservative, the model uses the 50-year storm event for Barnstable County. Assumptions 1. Ground cover was modeled as 100% impervious, to be conservative. 2. A minimum Tc of 6 minutes was chosen for all subcatchments. REV CALC. BY DATE CHECKED BY DATE APPROVED BY DATE 0 K. Pritchard 04/04/2024 344700CS005A.docx PAT 04/05/2024 P. Thompson 4/11/2024 Scenario: Base CM-1 CM-2 CM-3 CM-4 CM-5 CO-2 C O -4CO-7 C O -9 O-3 DRYWELL O-1 O-2 CB-5 CB-1 CB-2 CB-3 CB-4 MH-1 MH-2 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755- 1666 4/3/2024 StormCAD [10.03.04.53]Bentley Systems, Inc. Haestad Methods Solution Center344700SC001A.stsw Conduit FlexTable: B+T Hydraulic Spreadsheet Manning's n Diameter (in) Invert (Downstrea m) (ft) Hydraulic Grade Line (Out) (ft) Elevation Ground (Stop) (ft) Invert (Upstream) (ft) Hydraulic Grade Line (In) (ft) Elevation Ground (Start) (ft) Flow (cfs) System Intensity (in/h) System CA (acres) Upstream Inlet Tc (hours) Stop NodeStart Node 0.01315.021.8022.1132.0022.0022.4126.831.076.5790.1610.000O-1MH-1 0.01312.022.0022.4126.8322.2822.5926.430.546.6000.0820.100MH-1CB-2 0.01312.022.1422.4026.8322.2822.5826.430.536.6000.0790.100MH-1CB-1 0.01312.025.1025.4630.1525.5725.8331.840.386.6000.0580.100MH-2CB-4 0.01315.024.9025.2331.0025.1025.4630.150.866.5450.1310.000O-2MH-2 0.01312.026.0026.1930.1526.4926.7830.660.486.6000.0730.100MH-2CB-3 0.01312.019.8020.0125.8020.0020.3125.570.566.6000.0840.100O-3 DRYWELLCB-5 Excess Capacity (Full Flow) (cfs) Velocity (ft/s) Capacity (Full Flow) (cfs) Flow / Capacity (Design) (%) Slope (Calculated) (ft/ft) 7.504.768.5712.50.018 4.123.974.6711.70.017 3.123.303.6414.50.010 3.703.274.099.40.013 4.773.325.6415.30.008 6.134.926.627.30.034 6.815.537.377.60.043 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755-16664/3/2024 StormCAD [10.03.04.53]Bentley Systems, Inc. Haestad Methods Solution Center344700SC001A.stsw Conduit FlexTable: B+T Pipe Properties Number of Barrels Diameter (in) Slope (Calculated) (ft/ft) Cover (Stop) (ft) Cover (Start) (ft) Invert (Stop) (ft) Invert (Start) (ft) Elevation Ground (Stop) (ft) Elevation Ground (Start) (ft) Stop NodeStart Node 115.00.0188.953.5821.8022.0032.0026.83O-1MH-1 112.00.0173.833.1522.0022.2826.8326.43MH-1CB-2 112.00.0103.693.1522.1422.2826.8326.43MH-1CB-1 112.00.0134.055.2725.1025.5730.1531.84MH-2CB-4 115.00.0084.853.8024.9025.1031.0030.15O-2MH-2 112.00.0343.153.1726.0026.4930.1530.66MH-2CB-3 112.00.0435.004.5719.8020.0025.8025.57O-3 DRYWELLCB-5 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755- 1666 4/3/2024 StormCAD [10.03.04.53]Bentley Systems, Inc. Haestad Methods Solution Center344700SC001A.stsw 307 Main StreetHyannis, MassachusettsB+T Drawing No. 344700P018A-002Date: 04/03/2024 Scale: 1" = 50'Proposed Conditions HydraulicsFigure3MAIN STREETO L D C O L O N Y R O A D Attachment 5 TSS Removal, Water Quality Volume, and Recharge Calculations INSTRUCTIONS:Non-automated: Mar. 4, 2008 1. Sheet is nonautomated. Print sheet and complete using hand calculations. Column A and B: See MassDEP Structural BMP Table 2. The calculations must be completed using the Column Headings specified in Chart and Not the Excel Column Headings 3. To complete Chart Column D, multiple Column B value within Row x Column C value within Row 4. To complete Chart Column E value, subtract Column D value within Row from Column C within Row 5. Total TSS Removal = Sum All Values in Column D Location: A B C D E TSS Removal Starting TSS Amount Remaining BMP1 Rate1 Load*Removed (B*C)Load (C-D) WQI MIN. 44%100%44%56% Subsurface Infiltration 80%56%45%11% Total TSS Removal =89% Separate Form Needs to be Completed for Each Outlet or BMP Train Project:3447.00 Prepared By:Katherine Pritchard *Equals remaining load from previous BMP (E) Date:4/4/2024 which enters the BMP Hyannis TSS Removal Calculation344700SWM002A.xlsx Groundwater Recharge Volume Required: Rv = F x Impervious Area, where: Rv =Required Recharge Volume [Ac-ft] F =Target Depth Factor associated with each Hydrologic Soil Group (HSG) [in] Impervious Area =Total Pavement and Rooftop Area under Post-development Conditions [Ac] Impervious Area [Acres] Required Recharge Volume [Ac-ft] HSG "A", use F =0.6 in 1.071 0.054 Total Required Recharge Volume (Rv) =0.054 Ac-ft Capture Area Adjustment: (Ref: DEP Handbook V.3 Ch.1 P.27-28) Total Site Impervious Area (Total)= 1.07 Acres Impervious Area Draining to Infiltrative BMPs (infil) = 1.07 Acres (PDA-01B Impervious Area) Percent Imp. Area Draining to Infiltrative BMPs =100.0% Capture Area Adjustment Factor = (Total)/(Infil) = Ca =1.00 Adjusted Required Recharge Volume = Ca x Rv 0.054 Ac-ft Groundwater Recharge Volume Provided : Provided Recharge Volume [Ac-ft] 0.075 0.039 0.388 Total Provided Recharge Volume = 0.502 Ac-ft JOB NO.COMPUTED BY:KJP CHECKED BY: JOB:DATE:04/04/24 DATE: BMP Standard 3: Groundwater Recharge 3447.00 307 Main Street - Hyannis PROVIDED GROUNDWATER RECHARGE VOLUME IS GREATER THAN OR EQUAL TO THE REQUIRED RECHARGE VOLUME, THEREFORE PROPOSED STORMWATER MANAGEMENT DESIGN IS IN COMPLIANCE WITH STANDARD 3. Subsurface Infiltration System-1 = Subsurface Infiltration System-3 = Subsurface Infiltration System-2 = 344700SWM002A.xlsx Rv = Storage Volume Below Outlet [Ac-ft] Subsurface Infiltration System-1 0.075 Ac-ft 2.410 in/hr 0.018 Acres 20.724 Hours Subsurface Infiltration System-2 0.039 Ac-ft 8.270 in/hr 0.010 Acres 5.904 Hours Subsurface Infiltration System-3 0.388 Ac-ft 8.270 in/hr 0.093 Acres 6.051 Hours Note: JOB NO.COMPUTED BY:CHECKED BY: JOB:DATE:DATE: K = Standard 3: Drawdown 3447.00 307 Main St - Hyannis KJP 04/04/24 Rv = Drawdown Time =where: Bottom Area= Bottom Area of Recharge System [Ac] K= Infiltration Rate [in/hr] Rv (K) (Bottom Area) Bottom Area = Drawdown Time =< 72 Hours, Design is in compliance with the standard. < 72 Hours, Design is in compliance with the standard. 1. The infiltration BMPs have been designed to fully drain within 72 hours, therefore the proposed stormwater management design is in compliance with Standard 3 . 2. Infiltration Rates based on geotechnical report prepared by McPhail Associates dated 08/22/2023. Rv = K = Bottom Area = Drawdown Time = Rv = K = Bottom Area = Drawdown Time =< 72 Hours, Design is in compliance with the standard. 344700SWM002A.xlsx VWQ = Required Water Quality Volume [CF] AIMP = Post-development Impervious Area; may exclude roof top areas [Ac] Required Water Quality Volume: Drainage Area/ Treatment Train AIMP [Ac] DWQ [in] VWQ Required [CF] PDA-1A 0.094 1 341 PDA-2A 0.163 1 591 PDA-2B 0.136 1 494 PDA-2C 0.237 1 860 2,285 Cubic Feet Provided Water Quality Volume: Drainage Area/ Treatment Train Water Quality Volume Provided [CF] PDA-2A 3,267 PDA-2B 1,699 PDA-2C 16,901 21,867 Cubic Feet JOB NO.3447.00 COMPUTED BY:KJP CHECKED BY: JOB: 307 Main Street - Hyannis DATE:04/04/24 DATE: Total Provided Water Quality Volume: Standard 4: Water Quality Volume Summary DWQ = Water Quality Depth : 1-inch for discharges within a Zone II or Interim Wellhead Protection Area, to or near critical areas, runoff from LUHPPL, or exfiltration to soil with infiltration rate 2.4 in/hr or greater; ½-inch for discharges to other areas. WATER QUALITY VOLUME PROVIDED IS GREATER THAN OR EQUAL TO THE REQUIRED WATER QUALITY VOLUME, THEREFORE PROPOSED STORMWATER MANAGEMENT DESIGN IS IN COMPLIANCE WITH STANDARD 4. Subsurface Infiltration System-1 Subsurface Infiltration System-3 VWQ = (DWQ /12 in/ft) x (AIMP x 43,560 SF/Ac) where: BMP Total Required Water Quality Volume: Subsurface Infiltration System-2 344700SWM002A.xlsx Attachment 6 Site Owner’s Manual Site Owner’s Manual Hyannis Multi-family 307 Main Street Hyannis, Massachusetts Prepared for: WinnDevelopment 1 Washington Mall, Suite 500 Boston, Massachusetts, 02108 Prepared by: July XX, 2023 344700RP002A Hyannis Multi-family Site Owner’s Manual Hyannis, Massachusetts 344700RP002A Table of Contents i TABLE OF CONTENTS 1.0 INTRODUCTION ......................................................................................................................................... 1-1 2.0 SITE OWNER’S AGREEMENT ....................................................................................................................... 2-1 2.1 OPERATION AND MAINTENANCE COMPLIANCE STATEMENT ...................................................................................... 2-1 2.2 STORMWATER MAINTENANCE EASEMENTS ........................................................................................................... 2-1 2.3 RECORD KEEPING ............................................................................................................................................. 2-1 2.4 TRAINING ....................................................................................................................................................... 2-2 3.0 LONG-TERM POLLUTION PREVENTION PLAN ............................................................................................. 3-1 3.1 STORAGE OF MATERIALS AND WASTE .................................................................................................................. 3-1 3.2 VEHICLE WASHING ........................................................................................................................................... 3-1 3.3 ROUTINE INSPECTIONS AND MAINTENANCE OF STORMWATER BMPS ......................................................................... 3-1 3.4 SPILL PREVENTION AND RESPONSE ....................................................................................................................... 3-1 3.5 MAINTENANCE OF LAWNS, GARDENS, AND OTHER LANDSCAPED AREAS ...................................................................... 3-1 3.6 STORAGE AND USE OF FERTILIZERS, HERBICIDES, AND PESTICIDES .............................................................................. 3-2 3.7 PET WASTE MANAGEMENT ................................................................................................................................ 3-2 3.8 OPERATION AND MANAGEMENT OF SEPTIC SYSTEMS .............................................................................................. 3-2 3.9 SNOW AND DEICING CHEMICAL MANAGEMENT ..................................................................................................... 3-2 3.10 NUTRIENT MANAGEMENT PLAN ..................................................................................................................... 3-2 4.0 LONG-TERM OPERATION AND MAINTENANCE PLAN ................................................................................. 4-1 4.1 STORMWATER MANAGEMENT SYSTEM COMPONENTS ............................................................................................. 4-1 4.2 INSPECTION AND MAINTENANCE SCHEDULES ......................................................................................................... 4-1 4.2.1 General Maintenance for Mosquito Control ...................................................................................... 4-1 4.2.2 Deep Sump and Hooded Catch Basins and Drain Manholes .............................................................. 4-1 4.2.3 Hydrodynamic Separators.................................................................................................................. 4-2 4.2.4 Subsurface Infiltration System ........................................................................................................... 4-2 4.3 ESTIMATED OPERATION AND MAINTENANCE BUDGET ............................................................................................. 4-3 4.4 PUBLIC SAFETY FEATURES ........................................................................................ ERROR! BOOKMARK NOT DEFINED. FIGURES FIGURE 1: GRADING AND DRAINAGE PLAN APPENDICES APPENDIX A: OPERATION AND MAINTENANCE LOG APPENDIX B: LIST OF EMERGENCY CONTACTS APPENDIX C: HYDRODYNAMIC SEPARATOR TECHNICAL MANUAL Introduction 1-1 1.0 INTRODUCTION The Site Owner’s Manual complies with the Long-Term Pollution Prevention Plan (Standard 4) and the Long-Term Operation and Maintenance Plan (Standard 9) requirements of the 2008 Massachusetts Department of Environmental Protection (DEP) Stormwater Handbook. The Manual outlines source control and pollution prevention measures and maintenance requirements of stormwater best management practices (BMPs) associated with the proposed development. Site Owner’s Agreement 2-1 2.0 SITE OWNER’S AGREEMENT 2.1 Operation and Maintenance Compliance Statement Site Owner: WinnDevelopment 1 Washington Mall, Suite 500 Boston, MA 02108 Responsible Party: WinnDevelopment WinnDevelopment or their successors shall maintain ownership of the on-site stormwater management system as well as the responsibility for operation and maintenance during the post-development stages of the project. The site has been inspected for erosion and appropriate measures have been taken to permanently stabilize any eroded areas. All aspects of stormwater best management practices (BMPs) have been inspected for damage, wear and malfunction, and appropriate steps have been taken to repair or replace the system or portions of the system so that the stormwater at the site may be managed in accordance with the Stormwater Management Standards. Future responsible parties shall be notified of their continuing legal responsibility to operate and maintain the BMPs. The operation and maintenance plan for the stormwater BMPs is being implemented. ___________________________ ___________ Responsible Party Signature Date 2.2 Stormwater Maintenance Easements There are no off-site areas utilized for stormwater control, therefore no stormwater management easements are required. The Site Owner will have access to all stormwater practices for inspection and maintenance, including direct maintenance access by heavy equipment to structures requiring regular maintenance. 2.3 Record Keeping The Site Owner shall maintain a rolling log in which all inspections and maintenance activities for the past three years shall be recorded. The Operation and Maintenance Log includes information pertaining to inspections, repairs, and disposal relevant to the project’s stormwater management system. The Log is located in Appendix A. The Operation and Maintenance Log shall be made available to the Conservation Commission and the DEP upon request. The Conservation Commission and the DEP shall be allowed to enter and inspect the premises to evaluate and ensure that the responsible party complies with the maintenance requirements for each BMP. Site Owner’s Agreement 2-2 2.4 Training Employees involved in grounds maintenance and emergency response will be educated on the general concepts of stormwater management and groundwater protection. The Site Owner’s Manual will be reviewed with the maintenance staff. The staff will be trained on the proper course of action for specific events expected to be incurred during routine maintenance or emergency situations. Long-Term Pollution Prevention Plan 3-1 3.0 LONG-TERM POLLUTION PREVENTION PLAN In compliance with Standard 4 of the 2008 DEP Stormwater Management Handbook, this section outlines source control and pollution prevention measures to be employed on-site after construction. 3.1 Storage of Materials and Waste The site shall be kept clear of trash and debris at all times. Certain materials and waste products shall be stored inside or outside upon an impervious surface and covered, as required by local and state regulations. 3.2 Vehicle Washing No commercial vehicle washing shall take place on site. 3.3 Routine Inspections and Maintenance of Stormwater BMPs See Section 4.0 Long-Term Operation and Maintenance Plan, for routine inspection and maintenance requirements for all proposed stormwater BMPs. 3.4 Spill Prevention and Response A contingency plan shall be implemented to address the spill or release of petroleum products and hazardous materials and will include the following measures: 1. Equipment necessary to quickly attend to inadvertent spills or leaks shall be stored on-site in a secure but accessible location. Such equipment shall include but not be limited to the following: safety goggles, chemically resistant gloves and overshoe boots, water and chemical fire extinguishers, sand and shovels, suitable absorbent materials, storage containers and first aid equipment (i.e. Indian Valley Industries, Inc. 55-gallon Spill Containment kit or approved equivalent). 2. Spills or leaks shall be treated properly according to material type, volume of spillage and location of spill. Mitigation shall include preventing further spillage, containing the spilled material in the smallest practical area, removing spilled material in a safe and environmentally-friendly manner, and remediation of any damage to the environment. 3. For large spills, Massachusetts DEP Hazardous Waste Incident Response Group shall be notified immediately at 888-304-1133 and an emergency response contractor shall be consulted. 3.5 Maintenance of Lawns, Gardens, and other Landscaped Areas Lawns, gardens, and other landscaped areas shall be maintained regularly by the site owner. Vegetated and landscaped BMPs will be maintained as outlined in Section 4.0. Long-Term Pollution Prevention Plan 3-2 3.6 Storage and Use of Fertilizers, Herbicides, and Pesticides All fertilizers, herbicides, and pesticides shall be stored in accordance with local, state, and federal regulations. The application rate and use of fertilizers, herbicides, and pesticides on the site shall at no time exceed local, state, or federal specifications. 3.7 Pet Waste Management Pet owners shall be required to pick up after their animals and dispose of waste in the trash. 3.8 Operation and Management of Septic Systems The proposed development will be serviced by Town sewer and there are no proposed septic systems. 3.9 Snow and Deicing Chemical Management Snow removal and use of deicing chemicals at the proposed development shall comply with the following requirements:  Plowed snow shall be placed within landscape areas to the maximum extent practicable. The following maintenance measures shall be undertaken at all snow disposal sites:  Debris shall be cleared from an area prior to using it for snow disposal.  Debris and accumulated sediments shall be cleared from the site and properly disposed of at the end of the snow season and no later than May 15.  In accordance with the Massachusetts General Laws, Chapter 85, Section 7A, salt and other de-icing chemicals will be stored at an indoor location. Salt and other deicing chemicals shall be stored in accordance with Massachusetts General Law.  Sand piles shall be contained and stabilized to prevent the discharge of sand to wetlands or water bodies, and, where feasible, covered.  Salt storage piles shall be located outside of the 100-year floodplain.  The application of salt on the proposed parking areas and driveway shall at no time exceed state or local requirements. 3.10 Nutrient Management Plan A nutrient management plan is required if a Total Maximum Daily Load (TMDL) has been developed that indicates that use of fertilizers containing nutrients or other specific pollutants must be reduced. The Project is located within the Cape Cod Watershed which has a TMDL for Pathogens and is also located in the vicinity of Lewis Bat and Halls Creek which has a TMDL for Total Nitrogen. Nitrogen is a nutrient that is a natural part of an aquatic ecosystem; it is also the most abundant element in the air we breathe. In unaltered natural processes most nitrogen is Long-Term Pollution Prevention Plan 3-3 absorbed or retained by natural forest and wetland vegetation. In most marine and coastal waters the limiting nutrient for plant growth is nitrogen. Nitrogen concentrations beyond those expected naturally contribute to undesirable conditions, including the promotion of excessive growth of plants, algae and nuisance vegetation. Excessive nitrogen can also contribute to periodic extreme decreases in dissolved oxygen concentrations that can threaten aquatic life. Nitrogen enters coastal waters typically from the natural background of the watershed, combined sewer overflows, septic systems, fertilizers, atmospheric deposition, animal feeding operations, and stormwater runoff. Stormwater can pick-up nitrogen from fertilizers, pet and yard waste. The proposed stormwater management system will provide more than 1-inch of runoff retention from the impervious area on-site. Per the table 3-10 of Appendix F of the Massachusetts MS4 permit this will mitigate 100% of the total nitrogen in the stormwater runoff from the Project. 4.0 LONG-TERM OPERATION AND MAINTENANCE PLAN This section outlines the stormwater best management practices (BMPs) associated with the proposed stormwater management system and identifies the long-term inspection and maintenance requirements for each BMP. 4.1 Stormwater Management System Components The following table outlines the type and quantity of the BMPs and their general location. Please reference the site plan(s) provided in the Figures section for exact location. All stormwater best management practices are accessible for maintenance from either the development driveway or parking areas. BMP Type Quantity Location Catch Basins/Drain Manholes 6 Throughout paved parking area. Hydrodynamic Separators 3 Throughout paved parking area. Subsurface Infiltration System 3 Throughout paved parking area. 4.2 Inspection and Maintenance Schedules 4.2.1 General Maintenance for Mosquito Control If necessary to minimize mosquito breeding, a licensed pesticide applicator shall apply larvicides, such as Bacillus sphaericus (Bs) to all catch basins sumps, and water quality inlets. Larvicides shall be applied in compliance with all pesticide label requirements, and will be applied during or immediately after wet weather, unless the product used can withstand extended dry periods. Ensure all manhole covers, and inspection ports are secure to reduce the likelihood of mosquitoes laying eggs in standing water. 4.2.2 Deep Sump and Hooded Catch Basins and Drain Manholes Catch basins and drain manholes shall be inspected four times per year, including after the foliage season. Other inspection and maintenance requirements include:  Units shall be cleaned (organic material, sediment and hydrocarbons removed) four times per year or whenever the depth of deposits is greater than or equal to one half the depth from the bottom of the invert of the lowest pipe in the basin.  Cleanout shall always occur after street sweeping.  If any evidence of hydrocarbons is found during inspection, the material shall be immediately removed using absorbent pads or other suitable measures and disposed of legally.  Remove other accumulated debris as necessary.  Transport and disposal of accumulated sediment off-site shall be in accordance with applicable local, state and federal guidelines and regulations. 4.2.3 Hydrodynamic Separators Maintenance of hydrodynamic separators shall be performed according the recommendations set forth by the manufacturer (see Appendix C. Hydrodynamic Separator Technical Manual for complete installation, operation and maintenance procedures). Inspection and maintenance procedures for proprietary devices are provided below:  Units shall be inspected post-construction, prior to being put into service.  Units shall be inspected not less than twice per year following installation and no less than once per year thereafter.  Units shall be inspected immediately after any oil, fuel or chemical spill.  All inspections shall include checking the oil level and sediment depth in the unit.  Removal of sediments/oils shall occur per manufacturer recommendations.  A licensed waste management company shall remove captured petroleum waste products from any oil, chemical or fuel spills and dispose.  OSHA confined space entry protocols shall be followed if entry into the unit is required. 4.2.4 Subsurface Infiltration System The subsurface infiltration system shall be inspected twice per year. The inlets shall be inspected, and all debris that may clog the system shall be removed. 4.3 Estimated Operation and Maintenance Budget An operations and maintenance budget was prepared to approximate the annual cost of the inspections required in compliance with the DEP Stormwater Management Policy. The table below estimates the annual cost to inspect and maintain each proposed BMP, based on the requirements in Section 4.2. BMP Type # of BMPS Annual O&M Cost (per BMP)1 Total Cost Mosquito Control 19 $50-$100 $950-$1,900 Catch Basins and Drain Manholes 6 $200-$400 $1,200-$2,400 Hydrodynamic Separators 3 $100-$300 $300-$900 Subsurface Infiltration Systems 3 $200-$400 $600-$1200 Total $3,050-$6,400 Figures Figure 1: Grading and Drainage Plan 1 Annual maintenance cost is based on estimate of the cost to complete all inspection and maintenance measures outlined in Section 4.2. For BMPs that require sediment removal at regular intervals (i.e. every 5 or 10 years), the annual cost includes the annual percentage of that cost. Appendices Appendix A Operation and Maintenance Log Hyannis Multi-family Operation and Maintenance Log Hyannis, Massachusetts 344700RP002A OPERATION AND MAINTENANCE LOG This template is intended to comply with the operation and maintenance log requirements of the 2008 DEP Stormwater Management Handbook. Copies of this log should be made for all inspections and kept on file for three years from the inspection date. Name/Company of Inspector: Date/Time of Inspection: Weather Conditions: (Note current weather and any recent precipitation events) Stormwater BMP Inspection Observations Actions Required Appendix B List of Emergency Contacts Hyannis Multi-family Operation and Maintenance Log Hyannis, Massachusetts 344700RP002A List of Emergency Contacts Dial 911 in case of emergency Massachusetts DEP Hazardous Waste Incident Response Group (888)304-1133 Town of Barnstable Fire Department Emergencies: Dial 911 3249 Main Street Barnstable, MA 02630 Tel: (508) 362-3312 Fire Chief: Christopher A. Beal Hyannis Fire Department Emergencies: Dial 911 95 High School Road Ext. Hyannis, MA 02601 Tel: (508) 775-1300 Chief of Department: Peter J. Burke, Jr. Town of Barnstable Police Department Emergencies: Dial 911 1200 Phinney’s Lane Hyannis, MA 02601 Tel: (508) 790-4167 Police Chief: Matthew K. Sonnabend Appendix C Hydrodynamic Separator Technical Manual Attachment 7 Draft Stormwater Pollution Prevention Plan DRAFT DRAFT Stormwater Pollution Prevention Plan 307 Main Street 307 Main Street Hyannis, Massachusetts Prepared for: WinnDevelopment 1 Washington Mall, Suite 500 Boston, Massachusetts, 02108 Prepared by: SWPPP Preparation Date: Draft April 2024 Estimated Project Start Date: TBD Estimated Project Completion Date: TBD 344700RP005A.docx DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Table of Contents i Table of Contents 1.0 CONTACT INFORMATION/RESPONSIBLE PARTIES ..................................................... 1 1.1 Operator(s) / Subcontractor(s) ........................................................................................ 1 1.2 Stormwater Team ............................................................................................................ 2 2.0 SITE EVALUATION, ASSESSMENT, AND PLANNING .................................................... 4 2.1 Project/Site Information .................................................................................................. 4 2.2 Discharge Information ..................................................................................................... 5 2.3 Nature of the Construction Activities .............................................................................. 7 2.4 Sequence and Estimated Dates of Construction Activities .............................................. 8 2.5 Authorized Non-Stormwater Discharges ......................................................................... 9 2.6 Site Plans ........................................................................................................................ 10 3.0 DOCUMENTATION OF COMPLIANCE WITH OTHER FEDERAL REQUIREMENTS.......... 12 3.1 Endangered Species Protection ..................................................................................... 12 3.2 Historic Property Screening Process .............................................................................. 13 3.3 Safe Drinking Water Act Underground Injection Control Requirements ...................... 13 4.0 EROSION AND SEDIMENT CONTROLS AND DEWATERING PRACTICES ...................... 14 4.1 Natural Buffers or Equivalent Sediment Controls ......................................................... 14 4.2 Perimeter Controls ......................................................................................................... 15 4.3 Sediment Track-Out ....................................................................................................... 16 4.4 Stockpiles or Debris Piles Comprised of Sediment or Soil ............................................. 17 4.5 Minimize Dust ................................................................................................................ 18 4.6 Minimize Steep Slope Disturbances .............................................................................. 18 4.7 Topsoil ............................................................................................................................ 19 4.8 Soil Compaction ............................................................................................................. 19 4.9 Storm Drain Inlets .......................................................................................................... 20 4.10 Sediment Basins or Similar Impoundments ................................................................... 21 4.11 Chemical Treatment....................................................................................................... 21 4.12 Dewatering Practices ..................................................................................................... 22 4.13 Site Stabilization ............................................................................................................. 24 5.0 POLLUTION PREVENTION CONTROLS ..................................................................... 26 5.1 Potential Sources of Pollution........................................................................................ 26 5.2 Spill Prevention and Response ....................................................................................... 28 5.3 Fueling and Maintenance of Equipment or Vehicles ..................................................... 29 5.4 Washing of Equipment and Vehicles ............................................................................. 29 5.5 Storage, Handling, and Disposal of Building Products, Materials, and Wastes............. 30 5.6 Washing of Applicators and Containers used for Stucco, Paint, Concrete, Form Release Oils, Cutting Compounds, or Other Materials ........................................................................ 35 DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Table of Contents ii 5.7 Application of Fertilizers ................................................................................................ 37 6.0 INSPECTION, MAINTENANCE, AND CORRECTIVE ACTION ........................................ 39 6.1 Inspection Personnel and Procedures ........................................................................... 39 6.2 Corrective Action ........................................................................................................... 40 6.3 Delegation of Authority ................................................................................................. 42 7.0 Recordkeeping and Training .................................................................................. 43 7.1 Recordkeeping ............................................................................................................... 43 7.2 Log of Changes to the SWPPP ........................................................................................ 43 7.3 General Training Requirements for Stormwater Team Members ................................ 43 7.4 Training Requirements for Persons Conducting Inspections ........................................ 44 8.0 CERTIFICATION AND NOTIFICATION ....................................................................... 45 8.1 Signature, Plan Review, and Making Plans Available .................................................... 45 8.2 Notice of Permit Coverage ............................................................................................. 45 8.3 Operator CERTIFICATION ............................................................................................... 46 9.0 SWPPP APPENDICES .............................................................................................. 47 DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Table of Contents iii LIST OF APPENDICES APPENDIX A: SITE PLANS APPENDIX B: COPY OF 2022 CGP APPENDIX C: NOI AND EPA AUTHORIZATION EMAIL APPENDIX D: SITE INSPECTION FORM AND DEWATERING INSPECTION FORM APPENDIX E: CORRECTIVE ACTION LOG APPENDIX F: SWPPP AMENDMENT LOG APPENDIX G: SUBCONTRACTOR CERTIFICATIONS/AGREEMENTS APPENDIX H: GRADING AND STABILIZATION ACTIVITIES LOG APPENDIX I: TRAINING DOCUMENTATION APPENDIX J: DELEGATION OF AUTHORITY APPENDIX K: ENDANGERED SPECIES DOCUMENTATION APPENDIX L: HISTORIC PRESERVATION DOCUMENTATION APPENDIX M: RAINFALL GAUGE RECORDING APPENDIX N: TURBIDITY MONITORING SAMPLING DOCUMENTATION APPENDIX O: TEMPORARY SEDIMENT BASIN SIZING CALCULATION DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Contact Information 1 1.0 CONTACT INFORMATION/RESPONSIBLE PARTIES 1.1 OPERATOR(S) / SUBCONTRACTOR(S) Operator(s): Company: Contractor Name TBD Name: Address: City: State: ZIP Code: Telephone: Email: Subcontractor(s): Company: TBD Name: Address: City: State: ZIP Code: Telephone: Email: Area of Control: Site Work Contractor Emergency 24-Hour Contact: Company: TBD Name: Telephone: DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Contact Information 2 1.2 STORMWATER TEAM Name and/or Position, and Contact Responsibilities I Have Completed Training Required by CGP Part 6.2 I Read/Understand the Applicable Requirements of the CGP Beals and Thomas Katherine Pritchard 508.366.0560 kpritchard@bealsandthomas.com SWPPP Preparer ☒ Yes ☐ No ☒ Yes Date: 6/12/2023 TBD Personnel Responsible for Installation & Maintenance of Stormwater BMPs ☐ Yes ☐ No ☐ Yes Date: Click here to enter a date. TBD Personnel Responsible for the Application and Storage of Treatment Chemicals ☐ Yes ☐ No ☐ Yes Date: Click here to enter a date. TBD Inspection Personnel ☐ Yes ☐ No ☐ Yes Date: Click here to enter a date. TBD Personnel Responsible for Taking Corrective Actions ☐ Yes ☐ No ☐ Yes Date: Click here to enter a date. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Contact Information 3 Stormwater Team Members Who Conduct Inspections Pursuant to CGP Part 4 Name and/or Position and Contact Training(s) Received Date Training(s) Completed If Training is a Non-EPA Training, Confirm that it Satisfies the Minimum Elements of CGP Part 6.3.b TBD Insert Title of Training Received Date: Click here to enter a date. ☐ Principles and practices of erosion and sediment control and pollution prevention practices at construction sites ☐ Proper installation and maintenance of erosion and sediment controls and pollution prevention practices used at construction sites ☐ Performance of inspections, including the proper completion of required reports and documentation, consistent with the requirements of Part 4 TBD Insert Title of Training Received Date: Click here to enter a date. ☐ Principles and practices of erosion and sediment control and pollution prevention practices at construction sites ☐ Proper installation and maintenance of erosion and sediment controls and pollution prevention practices used at construction sites ☐ Performance of inspections, including the proper completion of required reports and documentation, consistent with the requirements of Part 4 DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 4 2.0 SITE EVALUATION, ASSESSMENT, AND PLANNING 2.1 PROJECT/SITE INFORMATION Project Name and Address Project/Site Name: 307 Main Street Street/Location: 307 Main Street City: Hyannis State: MA ZIP Code: 02601 County or Similar Government Division: Barnstable Project Latitude/Longitude Latitude: 41.6536079º N (decimal degrees) Longitude: - -70.2816045 º W (decimal degrees) Latitude/longitude data source: ☐ Map ☐ GPS ☒ Other (please specify): Google Maps Horizontal Reference Datum: ☐ NAD 27 ☐ NAD 83 ☒ WGS 84 Additional Site Information Is your site located on Indian country lands, or on a property of religious or cultural significance to an Indian Tribe? ☐ Yes ☒ No Is this project considered a federal facility? Yes No Are you applying for permit coverage as a “federal operator” as defined in Appendix A of the 2022 CGP? Yes No NPDES project or permit tracking number: TBD DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 5 2.2 DISCHARGE INFORMATION Does your project/site discharge stormwater into a Municipal Separate Storm Sewer System (MS4)? ☒ Yes ☐ No Are there any waters of the U.S. within 50 feet of your project’s earth disturbances? ☐ Yes ☒ No DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 6 For each point of discharge, provide a point of discharge ID (a unique 3-digit ID, e.g., 001, 002), the name of the first receiving water that receives stormwater directly from the point of discharge and/or from the MS4 that the point of discharge discharges to, and the following receiving water information, if applicable: Point of Discharge ID Name of receiving water that receives stormwater discharge: Is the receiving water impaired (on the CWA 303(d) list)? If yes, list the pollutants that are causing the impairment: Has a TMDL been completed for this receiving waterbody? If yes, list TMDL Name and ID: Pollutant(s) for which there is a TMDL: Is this receiving water designated as a Tier 2, Tier 2.5, or Tier 3 water? If yes, specify which Tier (2, 2.5, or 3)? 001 Barnstable MS4 ☐ Yes ☒ No ☒ Yes ☐ No Noted Below Noted Below ☐ Yes ☒ No MassDEP has issued a TMDL for the Cape Cod Watershed for Pathogens and further has issued a TMDL for Lewis Bay and Halls Creek for Total Nitrogen. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 7 2.3 NATURE OF THE CONSTRUCTION ACTIVITIES General Description of Project Provide a general description of the nature of your construction activities, including the age or dates of past renovations for structures that are undergoing demolition: The Project proposes to construct a 120-unit mixed income housing complex and supporting site improvements at the gateway of Hyannis’ unique walkable downtown. In alignment with the goals of the Downtown Hyannis Rezoning effort, the Barnstable Local Comprehensive Plan, and the Housing Production Plan, the Project proposes to demolish an existing vacant bank building having a brutalist architectural design at the key junction of Main Street and Old Colony Road. In its place a new mixed income multifamily residential building will be constructed, featuring curated public space at the intersection of Main Street and Old Colony. Is this project in response to a public emergency? Yes No Business days and hours for the project: Per Town Regulations Size of Construction Site Size of Property 1.75 acres Total Area Expected to be Disturbed by Construction Activities 1.75 acres Maximum Area Expected to be Disturbed at Any One Time, Including On-site and Off-site Construction Support Areas 1.75 acres Type of Construction Site (check all that apply): ☐ Single-Family Residential ☒ Multi-Family Residential ☐ Commercial ☐ Industrial ☐ Institutional ☐ Highway or Road ☐ Utility ☐ Other ____________________________ Will you be discharging dewatering water from your site? ☐ Yes ☒ No If yes, will you be discharging dewatering water from a current or former Federal or State remediation site? ☐ Yes ☐ No DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 8 2.4 SEQUENCE AND ESTIMATED DATES OF CONSTRUCTION ACTIVITIES Estimated Timeline of Activity Construction Activity and BMP Descriptions TBD Before any site grading activities begin 1. Stake Limit of Construction. Workers shall be informed that no construction activity is to occur beyond this limit at any time. 2. Clear vegetation as necessary within the limits of construction. 3. Grub the areas where silt fence is required, removing stumps and roots as necessary. The existing ground surface shall be disturbed as little as possible prior to the start of construction. 4. Install silt fence and straw bales as shown on the plans. An adequate stockpile of erosion control materials shall be on site at all times for emergency or routine replacement and shall include materials to repair silt fences, straw bales, or any other devices planned for use during construction. 5. Install storm drain inlet protection. 6. Construct stabilized construction exits. 7. Construct staging and materials storage area. 8. Install temporary sanitary facilities and dumpsters or enclosed trash container if a dumpster is not feasible for the project. TBD Site grading 1. Begin site clearing and grubbing operations. 2. Commence excavation of stormwater management basins to act as temporary sedimentation basins during construction. 3. Commence construction of temporary drainage channels to direct runoff to sedimentation basin(s) during construction. Check dams shall be installed along the temporary drainage channels to reduce velocities and collect sediment. 4. Begin overall site grading and topsoil stripping. 5. Establish topsoil stockpile. 6. Install silt fences around stockpile and cover stockpiles. 7. Disturbed areas where construction will cease for more than 14 days shall be stabilized with erosion controls. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 9 TBD Infrastructure (utilities, parking lot, etc.) 1. Construct temporary concrete washout area. 2. Install utilities, storm drains, sanitary sewers, and water services. 3. Install gutters, curbs, and prepare pavement subgrade. TBD Building Construction 1. Begin construction of building foundations and structures. 2. Roadway paved, exterior building constructed 3. Remove temporary concrete washout area. 4. Implement winter stabilization procedures. TBD Final stabilization and landscaping 1. Finalize pavement activities. 2. Remove all temporary control BMPs and stabilize any areas disturbed by their removal with erosion controls 3. Prepare final seeding and landscaping. 4. Monitor stabilized areas until final stabilization is reached. 2.5 AUTHORIZED NON-STORMWATER DISCHARGES List of Authorized Non-Stormwater Discharges Present at the Site Authorized Non-Stormwater Discharge Will or May Occur at Your Site? Discharges from emergency fire-fighting activities ☒ Yes ☐ No Fire hydrant flushings ☒ Yes ☐ No Landscape irrigation ☒ Yes ☐ No Water used to wash vehicles and equipment ☐ Yes ☒ No Water used to control dust ☒ Yes ☐ No Potable water including uncontaminated water line flushings ☒ Yes ☐ No External building washdown (soaps/solvents are not used and external surfaces do not contain hazardous substances) ☐ Yes ☒ No Pavement wash waters ☐ Yes ☒ No Uncontaminated air conditioning or compressor condensate ☒ Yes ☐ No Uncontaminated, non-turbid discharges of ground water or spring water ☐ Yes ☒ No Foundation or footing drains ☐ Yes ☒ No Uncontaminated construction dewatering water ☐ Yes ☒ No DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 10 2.6 SITE PLANS See Appendix A for the Site Plans. The Topographic Plan shows the existing site conditions and its current features. The Site Plans show the developed site. The Site Plans include: Boundaries of the property and of the locations where construction will occur, including:  Approximate slopes before and after major grading activities. Note any areas of steep slopes, as defined in CGP Appendix A;  Locations where sediment, soil, or other construction materials will be stockpiled;  Locations of any crossings of receiving waters;  Designated points where vehicles will exit onto paved roads;  Locations of structures and other impervious surfaces upon completion of construction; and  Locations of on-site and off-site construction support activity areas covered by the permit (see CGP Part 1.2.1.c). Locations of any receiving waters, including wetlands, within your site and all receiving waters within one mile downstream of the site’s discharge point(s). Indicate which receiving waters are listed as impaired, and which are identified by your State, Tribe, or EPA as Tier 2, Tier 2.5, or Tier 3 waters. Any areas of Federally-listed critical habitat for endangered or threatened species within the action area of the site as defined in CGP Appendix A (Helpful resources: CGP Appendix D and www.epa.gov/npdes/construction-general-permit-cgp-threatened-and-endangered-species- eligibility). Type and extent of pre-construction cover on the site (e.g., vegetative cover, forest, pasture, pavement, structures). Drainage pattern(s) of stormwater and authorized non-stormwater before and after major grading activities. Stormwater and authorized non-stormwater discharge locations, including:  Locations where stormwater and/or authorized non-stormwater will be discharged to storm drain inlets, including a notation of whether the inlet conveys stormwater to a sediment basin, sediment trap, or similarly effective control; and  Locations where stormwater or allowable non-stormwater will be discharged directly to receiving waters, including wetlands (i.e., not via a storm drain inlet). DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Site Evaluation, Assessment and Planning 11  Locations where turbidity benchmark monitoring will take place to comply with Part 3.3, if applicable to your site.  Locations of all potential pollutant-generating activities identified in Part 7.2.3g (note: you should have those identified in Section 2.3 (Nature of the Construction Activities) in this SWPPP Template).  Designated areas where construction wastes that are covered by the exception in Part 2.3.3e.ii (i.e., they are not pollutant-generating) will be stored. Locations of all potential pollutant-generating activities identified in Part 7.2.3g (note: you should have those identified in Section 2.3 (Nature of the Construction Activities) in this SWPPP Template). Designated areas where construction wastes that are covered by the exception in Part 2.3.3e.ii (i.e., they are not pollutant-generating) will be stored. Locations of stormwater controls, including natural buffer areas and any shared controls utilized to comply with the permit. Locations where polymers, flocculants, or other treatment chemicals will be used and stored. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Documentation of Compliance 12 3.0 DOCUMENTATION OF COMPLIANCE WITH OTHER FEDERAL REQUIREMENTS 3.1 ENDANGERED SPECIES PROTECTION Eligibility Criterion Following the process outlined in Appendix D, under which criterion are you eligible for coverage under this permit? ☒ Criterion A: No ESA-listed species and/or designated critical habitat present in action area. Using the process outlined in Appendix D of the CGP, you certify that ESA-listed species and designated critical habitat(s) under the jurisdiction of the USFWS or NMFS are not likely to occur in your site’s “action area” as defined in Appendix A of the CGP. Please Note: NMFS’ jurisdiction includes ESA-listed marine and estuarine species that spawn in inland rivers. ☐ Check to confirm you have provided documentation in your SWPPP as required by CGP Appendix D (Note: reliance on State resources is not acceptable; see CGP Appendix D). To be determined. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Documentation of Compliance 13 3.2 HISTORIC PROPERTY SCREENING PROCESS Appendix E, Step 1 Do you plan on installing any stormwater controls that require subsurface earth disturbance, including, but not limited to, any of the following stormwater controls at your site? Check all that apply below, and proceed to Appendix E, Step 2. ☐ Dike ☐ Berm ☒ Catch Basin ☐ Pond ☒ Constructed Site Drainage Feature (e.g., ditch, trench, perimeter drain, swale, etc.) ☐ Culvert ☐ Channel ☐ Other type of ground-disturbing stormwater control Appendix E, Step 2 If you answered yes in Step 1, have prior professional cultural resource surveys or other evaluations determined that historic properties do not exist, or have prior disturbances at the site have precluded the existence of historic properties? ☒ YES ☐ NO  If yes, no further documentation is required for Section 3.2 of the Template and you may provide the prior documentation in your SWPPP. 3.3 SAFE DRINKING WATER ACT UNDERGROUND INJECTION CONTROL REQUIREMENTS Do you plan to install any of the following controls? Check all that apply below. ☐ Infiltration trenches (if stormwater is directed to any bored, drilled, driven shaft or dug hole that is deeper than its widest surface dimension, or has a subsurface fluid distribution system) ☒ Commercially manufactured pre-cast or pre-built proprietary subsurface detention vaults, chambers, or other devices designed to capture and infiltrate stormwater flow ☐ Drywells, seepage pits, or improved sinkholes (if stormwater is directed to any bored, drilled, driven shaft or dug hole that is deeper than its widest surface dimension, or has a subsurface fluid distribution system) DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 14 4.0 EROSION AND SEDIMENT CONTROLS AND DEWATERING PRACTICES This SWPPP contains a listing of the erosion and sediment control best management practices (BMPs) that will be implemented to control pollutants in stormwater discharges. The BMPs are categorized under one of the areas of BMP activity as described below:  Establish perimeter controls and sediment barriers  Minimize disturbed area and protect natural features and soil  Control stormwater flowing onto and through the project  Stabilize soils  Protect slopes  Protect storm drain inlets  Retain sediment on-site and control dewatering practices  Establish stabilized construction exits 4.1 NATURAL BUFFERS OR EQUIVALENT SEDIMENT CONTROLS Buffer Compliance Alternatives Are there any receiving waters within 50 feet of your project’s earth disturbances? ☐ YES ☒ NO DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 15 4.2 PERIMETER CONTROLS General  Perimeter controls will be installed along any perimeter areas of the site that are downslope from any exposed soil or other disturbed areas. Specific Perimeter Controls Sediment Control Barrier Description: A Sediment Control Barrier, consisting of entrenched straw bales, straw wattles, compost socks and siltation fencing, shall be installed along the downgradient side of the proposed project to decrease the velocity of sheet flows and intercept and detain small amounts of sediment from disturbed areas. Installation Sediment Control Barrier shall be installed prior to clearing and grubbing. Maintenance Requirements Damaged fencing shall be replaced. Concentrated flows shall be intercepted and rerouted. Sediment accumulations shall be removed before reaching a depth of 6 inches, or one-half of the above-ground height of the barrier, whichever is less. Deteriorated fencing material shall be replaced. Used fencing shall be properly disposed of. After a storm event, if there is evidence of stormwater circumventing or undercutting the perimeter control, extend controls and/or repair undercut areas to fix the problem. Design Specifications For more information, see plans and specifications. To prevent stormwater from circumventing the edge of the perimeter control, install the perimeter control on the contour of the slope and extend both ends of the control up slope (e.g., at 45 degrees) forming a crescent rather than a straight line. Silt Fence Description: Entrenched silt fence shall be installed to decrease the velocity of sheet flows and intercept and detain small amounts of sediment from disturbed areas. Installation Silt fence shall be installed prior to clearing and grubbing. Maintenance Requirements Damaged fencing shall be replaced. Concentrated flows shall be intercepted and rerouted. Sediment accumulations shall be removed before reaching a depth of 6 inches, or one-half of the above-ground height of the barrier, whichever is less. Deteriorated fencing material shall be replaced. Used fencing shall be properly disposed of. After a storm event, if there is evidence of stormwater circumventing or undercutting the perimeter control, extend controls and/or repair undercut areas to fix the problem. Design Specifications For more information, see plans and specifications. To prevent stormwater from circumventing the edge of the perimeter control, install the perimeter control on the contour of the slope and extend both ends of the control up slope (e.g., at 45 degrees) forming a crescent rather than a straight line. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 16 4.3 SEDIMENT TRACK-OUT General  Vehicle use shall be restricted to properly designated exit points;  Appropriate stabilization techniques shall be used at all points that exit onto paved roads;  Additional track-out controls shall be implemented as necessary to ensure that sediment removal occurs prior to vehicle exit; and  Where sediment has been tracked-out from the site onto paved roads, sidewalks, or other paved areas outside of the site, the deposited sediment shall be removed by the end of the next business day if track-out occurs on a non-business day. Track-out shall be removed by sweeping, shoveling, or vacuuming these surfaces, or by using similarly effective means of sediment removal. Specific Track-Out Controls Stabilized Construction Entrance/Exit Description: Temporary gravel or crushed stone construction entrances/exits or other means shall be used to minimize off-site movement of soil with vehicles. Construction access points shall be maintained to minimize tracking of soil onto public roads and existing parking lots to remain. If the rock entrance is not working to keep streets clean, then install wheel wash, sweep streets, or wash streets if wash water can be collected. Installation Stabilized construction entrance shall be installed prior to clearing and grubbing. Maintenance Requirements Stabilized construction entrances shall be inspected daily. Gravel or crushed stone shall be added if the pad is no longer in accordance with the specifications. If the construction entrance/ exit is not working to keep streets clean, then install wheel wash, sweep streets, or wash streets if wash water can be collected. Where sediment has been tracked off of the site, it shall be removed by the end of the same working day, or by the end of the next working day if track-out occurs on a non-work day. Remove sediment by sweeping, shoveling, or vacuuming roadways where sediment has been tracked out. Under no circumstances will tracked-out sediment be hosed or swept into any constructed or natural site drainage feature, storm drain inlet, or receiving water. Design Specifications For more information, see plans and specifications. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 17 4.4 STOCKPILES OR DEBRIS PILES COMPRISED OF SEDIMENT OR SOIL General  Locate the piles away from any constructed drainage features, storm drain inlets, and areas where stormwater flow is concentrated;  Install a sediment barrier along all downgradient perimeter areas of stockpiled soil or land clearing debris piles;  For piles that will be unused for 14 or more days, provide cover or appropriate temporary stabilization (consistent with Part 2.2.14);  You are prohibited from hosing down or sweeping soil or sediment accumulated on pavement or other impervious surfaces into any constructed or natural site drainage feature, storm drain inlet, or receiving water.  Topsoil stockpiles shall be established during grading activities. The silt fence and temporary erosion controls shall be installed immediately after the stockpile has been established. For piles that will be unused for 14 or more days provide cover over the stockpile or temporary stabilization to avoid direct contract with precipitation and wind. Install a sediment barrier along all downgradient perimeter areas of stockpiles. Specific Stockpile Controls Stockpiling Topsoil Description: Topsoil stripped from the immediate construction area shall be stockpiled as identified on the Site Plans and Sitework Specifications or as approved by the SWPPP preparer. Stockpiles shall be located outside of any natural buffers and away from any stormwater conveyances, drain inlets, and areas where stormwater flow is concentrated. Installation Topsoil stockpiles shall be established during grading activities. The silt fence and temporary erosion controls shall be installed immediately after the stockpile has been established. For piles that will be unused for 14 or more days provide cover over the stockpile or temporary stabilization to avoid direct contract with precipitation and wind. Install a sediment barrier along all downgradient perimeter areas of stockpiles. Maintenance Requirements The area shall be inspected weekly for erosion and immediately after storm events. Areas on or around the stockpile that have eroded shall be stabilized immediately with erosion controls. See following Silt Fence section for Maintenance and inspection procedures. Under no circumstances will soil or sediment accumulated on pavement or other impervious surfaces be hosed or swept into any constructed or natural site drainage feature, storm drain inlet, or receiving water. Design Specifications For more information, see plans and specifications. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 18 4.5 MINIMIZE DUST General  On areas of exposed soil, dust will be minimized through the appropriate application of water or other dust suppression techniques to control the generation of pollutants that could be discharged in stormwater from the site. Specific Dust Controls Mobile Dust Control Description: Dust from the site shall be controlled by using a mobile pressure-type distributor truck to apply water to disturbed areas. The mobile unit shall apply water at a rate of 300 gallons per acre and minimized as necessary to prevent runoff and ponding. Installation Dust control shall be implemented as needed once site grading has been initiated and during windy conditions (forecasted or actual wind conditions of 20 mph or greater) while site grading is occurring. Spraying of water shall be performed no more than three times a day during the months of May– September and once per day during the months of October–April or whenever the dryness of the soil warrants it. Maintenance Requirements At least one mobile unit shall be available at all times to distribute water to control dust on the project area. Each mobile unit shall be equipped with a positive shutoff valve to prevent over watering of the disturbed area. Design Specifications For more information, see plans and specifications. 4.6 MINIMIZE STEEP SLOPE DISTURBANCES General  The disturbance of steep slopes shall be minimized. Specific Steep Slope Controls Erosion Control Blanket Description: Erosion control blankets shall be used to provide stabilization for the slopes in the grass drainage channels and sediment basins, and on slopes greater than 3:1 throughout the site. Installation The erosion control blankets shall be installed in areas that have reached final grades (e.g., grass drainage channels, sediment basins). Maintenance Requirements The erosion control blanket shall be inspected weekly and immediately after storm events to determine if cracks, tears, or breaches have formed in the fabric; if so, the blanket shall be repaired or replaced immediately. Good contact with the soil shall be maintained and erosion shall not occur under the blanket. Any areas where the blanket is not in close contact with the ground shall be repaired or replaced. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 19 Erosion Control Blanket Design Specifications For more information, see plans and specifications. 4.7 TOPSOIL General  Native topsoil shall be preserved, unless infeasible. Specific Topsoil Controls Preserve Existing Vegetation Description: The preserved area of existing vegetation shall be as identified on the Site Plans and Sitework Specifications. Installation The preserved area of existing vegetation shall be surrounded with the orange-colored plastic mesh fence, and trees shall be marked before construction begins at the site. Maintenance Requirements The area shall be inspected weekly to ensure the temporary fence is intact and the trees are clearly marked. During construction, preserved areas of existing vegetation shall be surrounded by the orange-colored mesh fence and clearly marked at all times. Design Specifications For more information, see plans and specifications. 4.8 SOIL COMPACTION General In areas of the site where final vegetative stabilization will occur or where infiltration practices will be installed:  Vehicle and equipment use shall be restricted in areas where final vegetative stabilization will occur or where infiltration practices will be installed.  A Sediment Control Barrier shall be installed around the perimeter of all proposed infiltration areas to prevent construction vehicles from impacting the area. Specific Soil Compaction Controls Protect Proposed Infiltration Areas Description: A Sediment Control Barrier shall be installed around the perimeter of all proposed infiltration areas to prevent construction vehicles from impacting the area, to decrease the velocity of sheet flows, and to intercept and detain small amounts of sediment from disturbed areas. Installation The Sediment Control Barrier shall be installed after clearing and grubbing. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 20 Protect Proposed Infiltration Areas Maintenance Requirements Silt fence shall be inspected weekly, following storms, and daily during rainy periods. Damaged fencing shall be replaced. Concentrated flows shall be intercepted and rerouted. Sediment accumulations shall be removed before reaching a depth of 6 inches. Deteriorated fencing material shall be replaced. Used fencing shall be properly disposed of. Design Specifications For more information, see plans and specifications. 4.9 STORM DRAIN INLETS General  Install inlet protection measures that remove sediment from discharges prior to entry into any storm drain inlet that carries stormwater from your site to a receiving water, provided you have authority to access the storm drain inlet. Inlet protection measures are not required for storm drain inlets that are conveyed to a sediment basin, sediment trap, or similarly effective control; and  Clean, or remove and replace, the inlet protection measures as sediment accumulates, the filter becomes clogged, and/or performance is compromised. Where there is evidence of sediment accumulation adjacent to the inlet protection measure, remove the deposited sediment by the end of the same business day in which it is found or by the end of the following business day if removal by the same business day is not feasible. Specific Storm Drain Inlet Controls Filter Bags Description: Filter bag manufactured specifically for controlling sediment flow into all storm drain inlets to prevent coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Installation Filter Bags shall be installed prior to clearing and grubbing. Maintenance Requirements Filter Bags shall be cleaned, or removed and replaced, as sediment accumulates, the filter becomes clogged, and/or performance is compromised. Where there is evidence of sediment accumulation adjacent to the inlet protection measure, deposited sediment shall be removed by the end of the same business day in which it is found or by the end of the following business day if removal by the same business day is not feasible. Collected sediments shall NOT be washed into storm drains. Design Specifications For more information, see plans and specifications. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 21 4.10 SEDIMENT BASINS OR SIMILAR IMPOUNDMENTS General  Situate the basin or impoundment outside of any receiving water, and any natural buffers;  Design the basin or impoundment to avoid collecting water from wetlands;  Design the basin or impoundment to provide storage for either (1) the calculated volume of runoff from a 2-year, 24-hour storm, or (2) 3,600 cubic feet per acre drained.  Utilize outlet structures that withdraw water from the surface of the sediment basin or similar impoundment, unless infeasible.  Use erosion controls and velocity dissipation devices to prevent erosion at inlets and outlets.  Remove accumulated sediment to maintain at least one-half of the design capacity and conduct all other approximate maintenance to ensure the basin or impoundment remains in effective operation condition. Specific Sediment Basin Controls Temporary Sediment Basins Description: Temporary sediment basins are located throughout the site between construction and wetland resource areas. Refer to the Temporary Sediment Basin Sizing Calculation located in Appendix O. Several temporary sediment basins will be utilized as sediment forebays following construction. Installation Temporary Sediment Basins shall be installed during grading activities. Maintenance Requirements Temporary Sediment Basins shall be inspected weekly and following storms. Accumulated sediment shall be removed to maintain at least one-half of the design capacity. Damage to basin embankments and slopes shall be repaired. Conduct all other appropriate maintenance to ensure the basin/impoundment remains in effective operating condition. Design Specifications These basins provide 3,600 cubic feet of storage per acre drained, as required by the EPA. 4.11 CHEMICAL TREATMENT No chemical treatment will be used at the site. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 22 4.12 DEWATERING PRACTICES General Description: All groundwater or accumulated stormwater discharged from excavations, trenches, foundations, vaults, or other similar points of accumulation shall be routed to a sediment control (e.g., sediment basins, sediment traps, pumped water filter bag) designed to prevent discharges with visual turbidity. Visual turbidity is present when there is a sediment plume in the discharge or the discharge appears cloudy, or opaque, or has a visible contrast that can be identified by an observer. All dewatering practices shall conform to the following:  Visible floating solids or foam shall not be discharged;  The discharge must not cause the formation of a visible sheen on the water surface, or visible oily deposits on the bottom or shoreline of the receiving water. An oil- water separator or suitable filtration device (such as a cartridge filter) designed to remove oil, grease, or other products if dewatering water is found to or expected to contain these materials shall be used;  To the extent feasible, utilize well-vegetated (e.g., grassy or wooded), upland areas of the site to infiltrate dewatering water before discharge. In no case will surface waters be considered part of the treatment area;  Stable, erosion-resistant surfaces (e.g., well-vegetated grassy areas, clean filter stone, geotectile underlayment) shall be used to discharge from dewatering controls;  Dewatering controls, such as pumped water filter bags, shall not be placed on steep slopes;  Velocity dissipaters shall be installed at all points where dewatering activities are discharged to the surface.  With backwash water, either haul it away for disposal or return it to the beginning of the treatment process; and  Replace and clean the filter media used in dewatering devices when the pressure differential equals or exceeds the manufacturer’s specifications.  Construction dewatering effluent shall not be discharged into stormwater infiltration systems. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 23 Installation Schedule: Install settling or filtration methods prior to commencing dewatering. Engineer is required to provide or approve settling of filtration method design prior to installation. Maintenance and Inspection: Settling of filtration controls shall be inspected weekly and following storms. Sediment shall be removed when it reaches a depth of one foot, or half the design capacity whichever is less. Dewatering practices shall be inspected during the discharge once per day on which the discharge occurs. A dewatering inspection report must be completed within 24 hours of completing the inspection. If discharging dewatering water to a sensitive water, the operator is required to conduct turbidity benchmark monitoring and report the data to the EPA. See CGP Part 3.3. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 24 4.13 SITE STABILIZATION Total Amount of Land Disturbance Occurring at Any One Time ☒ Five Acres or less ☐ More than Five Acres Temporary Stabilization ☒ Vegetative ☐ Non-Vegetative ☒ Temporary ☐ Permanent Description:  Initiation of temporary vegetative cover shall occur immediately where construction will cease for more than 14 days. It shall be established using hydroseeding for areas of exposed soil (including stockpiles). Installation Initiate the installation of stabilization measures immediately in any areas of exposed soil where construction activities have permanently ceased or will be temporarily inactive for 14 or more calendar days. Completion Must be completed as soon as practicable, but no later than 7 calendar days after stabilization has been initiated. Maintenance Requirements Stabilized areas shall be inspected until a dense cover of vegetation has become established. If failure is noticed at the seeded area, the area shall be reseeded, fertilized, and mulched immediately. Design Specifications For more information, see plans and specifications. Mulching ☐ Vegetative ☒ Non-Vegetative ☒ Temporary ☐ Permanent Description:  Hydromulching shall provide immediate protection to exposed soils during short periods of disturbance. Hydromulch shall also be applied in areas that have been seeded for temporary or permanent stabilization. Installation Initiate the installation of stabilization measures immediately in any areas of exposed soil where construction activities have permanently ceased or will be temporarily inactive for 14 or more calendar days. Completion Must be completed as soon as practicable, but no later than 7 calendar days after stabilization has been initiated. Maintenance Requirements Mulched areas shall be inspected to check for movement of mulch or erosion. If washout, breakage, or erosion occurs, the surface shall be repaired, and new mulch shall be applied to the damaged area. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Erosion and Sediment Controls 25 Mulching Design Specifications For more information, see plans and specifications. Final Stabilization ☒ Vegetative ☐ Non-Vegetative ☐ Temporary ☒ Permanent Description:  Initiation of permanent stabilization measures shall occur immediately after the final design grades are achieved and earth moving activities cease. Vegetative cover shall be used to stabilize exposed soils.  Establish uniform, perennial vegetation (i.e., evenly distributed, without large bare areas) to provide 70 percent or more of the vegetative cover native to local undisturbed areas. Installation Initiate the installation of stabilization measures immediately in any areas of exposed soil where construction activities have permanently ceased. Completion Must be completed as soon as practicable, but no later than 7 calendar days after stabilization has been initiated. Maintenance Requirements All seeded areas shall be inspected weekly during construction activities and after storm events until a dense cover of vegetation has been established. If failure is noticed at the seeded area, the area shall be reseeded, fertilized, and mulched immediately. Care shall be taken to avoid compacting newly placed topsoil. After construction is completed at the site, permanently stabilized areas shall be monitored until final stabilization is reached. Design Specifications For more information, see plans and specifications. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 26 5.0 POLLUTION PREVENTION CONTROLS 5.1 POTENTIAL SOURCES OF POLLUTION Construction Site Pollutants Potential sources of sediment include clearing and grubbing operations, grading and site excavation operations, vehicle tracking, topsoil stripping and stockpiling, and landscaping operations. Potential sources of non-sediment pollutants:  Combined Staging Area — small fueling activities, minor equipment maintenance, sanitary facilities, and hazardous waste storage.  Materials Storage Area — general building materials, solvents, adhesives, paving materials, paints, aggregates, trash, and so on.  Construction Activity — paving, curb/gutter installation, concrete pouring/mortar/stucco, and building construction.  Concrete Washout Area Material/ Chemical Physical Description Stormwater Pollutants Location[1] Pesticides/ Herbicides Various colored to colorless liquid, powder, pellets, or grains Chlorinated hydrocarbons, organophosphates, carbamates, arsenic Pesticides used in outdoor locations to control insects. Herbicides used for noxious weed control [2]Fertilizer Liquid or solid grains Nitrogen, phosphorous Newly seeded areas Cleaning solvents Colorless, blue, or yellow-green liquid Perchloroethylene, methylene chloride, trichloroethylene, petroleum distillates No equipment cleaning allowed in project limits Asphalt Black solid Oil, petroleum distillates Streets, parking areas, and roofing Glue/ adhesives White or yellow liquid Polymers, epoxies Building construction DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 27 Material/ Chemical Physical Description Stormwater Pollutants Location[1] Paints Various colored liquids Metal oxides, Stoddard solvent, talc, calcium carbonate, arsenic Building construction Curing compounds Creamy white liquid Naphtha Curb and gutter, walkways Wood preservative s Clear amber or dark brown liquid Stoddard solvent, petroleum distillates, arsenic, copper, chromium Timber pads and building construction Hydraulic oil/fluids Brown oily petroleum hydrocarbon Mineral oil Leaks or broken hoses from equipment Gasoline Colorless, pale brown or pink petroleum hydrocarbon Benzene, ethyl benzene, toluene, xylene, MTBE Secondary containment/ staging area Diesel Fuel Clear, blue-green to yellow liquid Petroleum distillate, oil & grease, naphthalene, xylenes Secondary containment/ staging area Kerosene Pale yellow liquid petroleum hydrocarbon Coal oil, petroleum distillates Secondary containment/ staging area Antifreeze/ coolant Clear green/yellow liquid Ethylene glycol, propylene glycol, heavy metals (copper, lead, zinc) Leaks or broken hoses from equipment Sanitary toilets Various colored liquid Bacteria, parasites, and viruses Staging area DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 28 5.2 SPILL PREVENTION AND RESPONSE Description: i. Employee Training: All employees shall be trained as detailed in the Inspection and Maintenance section of this report. ii. Vehicle Maintenance: Vehicles and equipment shall be maintained off-site. All vehicles and equipment including subcontractor vehicles shall be checked for leaking oil and fluids. Vehicles leaking fluids shall not be allowed on-site. iii. Hazardous Material Storage: Hazardous materials shall be stored in accordance with this report and federal and municipal regulations. iv. Spill Kits: Spill kits shall be kept within the materials storage area. Spills: All spills shall be cleaned up immediately upon discovery. Spent absorbent materials and rags shall be hauled off-site immediately after the spill is cleaned up for disposal at an approved landfill. Spills large enough to discharge to surface water shall be reported to the National Response Center at 1-800-424-8802 and MA DEP at 888-304- 1133. v. Material safety data sheets: A material inventory and emergency contact information shall be maintained at the on- site project trailer. Installation Schedule: The spill prevention and control procedures shall be implemented once construction begins on-site. Maintenance and Inspection: All personnel shall be instructed on the correct procedures for spill prevention and control. Notices that state these practices shall be posted in the office trailer, and the individual who manages day-to- day site operations shall be responsible for seeing that these procedures are followed. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 29 5.3 FUELING AND MAINTENANCE OF EQUIPMENT OR VEHICLES General Description: Several types of vehicles and equipment will likely be used on-site throughout the project, including graders, scrapers, excavators, loaders, paving equipment, rollers, trucks and trailers, backhoes, and forklifts. All major equipment/ vehicle fueling and maintenance shall be performed outside of wetland buffer zones. When vehicle fueling must occur on-site, the fueling activity shall occur in the staging area. Only minor equipment maintenance shall occur on-site. All equipment fluids generated from maintenance activities shall be disposed of into designated drums stored on spill pallets in accordance with the Material Handling and Waste Management Section. Absorbent, spill-cleanup materials and spill kits shall be available at the combined staging and materials storage area. Drip pans shall be placed under all equipment receiving maintenance and vehicles and equipment parked overnight. Installation Schedule: BMPs implemented for equipment and vehicle maintenance and fueling activities shall begin at the start of the project. Maintenance and Inspection: Inspect equipment/vehicle storage areas weekly and after storm events. Vehicles and equipment shall be inspected on each day of use. Leaks shall be repaired immediately, using dry cleanup measures where possible and eliminating the source of the discharge. Problem vehicle(s) or equipment shall be removed from the project site. Keep ample supply of spill- cleanup materials on-site and immediately clean up spills and dispose of materials properly. Do not clean surfaces by hosing-down the area 5.4 WASHING OF EQUIPMENT AND VEHICLES General  All equipment and vehicle washing shall be performed off site, except as required for wheel washes and concrete washout areas. See Concrete Washout in section 5.6 of this SWPPP. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 30 5.5 STORAGE, HANDLING, AND DISPOSAL OF BUILDING PRODUCTS, MATERIALS, AND WASTES 5.5.1 Building Materials and Building Products General  Provide either (1) cover (e.g., plastic sheeting, temporary roofs) to minimize the exposure of these products to precipitation and to stormwater, or (2) a similarly effective means designed to minimize the discharge of pollutants from these areas.  Exception: Minimization of exposure is not required in cases where the exposure to precipitation and to stormwater will not result in a discharge of pollutants, or where exposure of a specific material or product poses little risk of stormwater contamination (such as final products and materials intended for outdoor use). Specific Pollution Prevention Practices Establish Proper Building Material Staging Areas Description: Construction equipment and maintenance materials shall be stored at the combined staging area and materials storage areas. A watertight shipping container shall be used to store hand tools, small parts, and other construction materials. Nonhazardous building materials such as packaging material (wood, plastic, and glass), and construction scrap material (brick, wood, steel, metal scraps, and pipe cuttings) shall be stored in a separate covered storage facility adjacent to the shipping container. Very large items, such as framing materials and stockpiled lumber, shall be stored in the open in the materials storage area. Such materials shall be elevated on wood blocks to minimize contact with runoff. Implementation The materials storage area shall be installed after grading and before any infrastructure is constructed at the site. Maintenance Requirements The storage area shall be inspected weekly and after storm events. The storage area shall be kept clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. Perimeter controls, containment structures, covers, and liners shall be repaired or replaced as needed to maintain proper function. Design Specifications For more information, see plans and specifications. 5.5.2 Pesticides, Herbicides, Insecticides, Fertilizers, and Landscape Materials General  In storage areas, provide either (1) cover (e.g., plastic sheeting, temporary roofs) to minimize the exposure of these chemicals to precipitation and to stormwater, or (2) a DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 31 similarly effective means designed to minimize the discharge of pollutants from these areas; and  Comply with all application and disposal requirements included on the registered pesticide, herbicide, insecticide, and fertilizer label (see also Part 2.3.5). Specific Pollution Prevention Practices Establish Proper Pesticide, Herbicide, Insecticide, Fertilizer, and Landscape Material Staging Areas Description: All fertilizers, herbicides, insecticides and pesticides shall be stored in accordance with local, state, and federal regulations. At a minimum these materials shall be covered with plastic sheeting or a temporary roof to prevent contact with rainwater. Implementation The storage area shall be installed after grading and before any infrastructure is constructed at the site. Maintenance Requirements The storage area shall be inspected weekly and after storm events. The storage area shall be kept clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. Perimeter controls, containment structures, covers, and liners shall be repaired or replaced as needed to maintain proper function. Design Specifications 5.5.3 Diesel Fuel, Oil, Hydraulic Fluids, Other Petroleum Products, and Other Chemicals General For ALL chemical containers:  The containers shall be water-tight, and shall be kept closed, sealed, and secured when not being actively used;  A spill kit shall be available on site that is in good working condition (i.e., not damaged, expired, or used up). Personnel shall be available to respond immediately in the event of a leak or spill. If any chemical container has a storage capacity less than 55 gallons:  If stored outside, a spill containment pallet or similar device shall be used to capture small leaks or spills, If any chemical container has a storage capacity of 55 gallons or more:  Containers shall be stored a minimum of 50 feet from receiving waters, constructed or natural site drainage features, and storm drain inlets.  Either (1) cover (e.g., temporary roofs) to minimize the exposure of these containers to precipitation and to stormwater or (2) secondary containment (e.g., curbing, spill berms, DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 32 dikes, spill containment pallets, double-wall, above-ground storage tank) shall be provided.  Have a spill kit available on site that is in good working condition (i.e., not damaged, expired, or used up) and ensure personnel are available to respond immediately in the event of a leak or spill. If site constraints prevent you from storing chemical containers 50 feet away from receiving waters or the other site drainage features as required in CGP Part 2.3.3c.ii(b), document the specific reasons why the 50-foot setback is not feasible, and how you will store containers as far away as the site permits. 5.5.4 Hazardous or Toxic Waste General  Separate hazardous or toxic waste from construction and domestic waste;  Store waste in sealed containers, constructed of suitable materials to prevent leakage and corrosion, and labeled in accordance with applicable Resource Conservation and Recovery Act (RCRA) requirements and all other applicable Federal, State, Tribal, or local requirements;  Store all outside containers within appropriately-sized secondary containment (e.g., spill berms, dikes, spill containment pallets) to prevent spills from being discharged, or provide a similarly effective means designed to prevent the discharge of pollutants from these areas (e.g., storing chemicals in a covered area, having a spill kit available on site)  Dispose of hazardous or toxic waste in accordance with the manufacturer’s recommended method of disposal and in compliance with Federal, State, Tribal, and local requirements;  Clean up spills immediately, using dry clean-up methods, and dispose of used materials properly. You are prohibited from hosing the area down to clean surfaces or spills. Eliminate the source of the spill to prevent a discharge or a furtherance of an ongoing discharge; and  Follow all other Federal, State, Tribal, and local requirements regarding hazardous or toxic waste Insert general description of how you wil comply with CGP Part 2.3.3.d DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 33 Hazardous Materials and Waste Description: All hazardous waste materials such as oil filters, petroleum products, paint, and equipment maintenance fluids shall be stored in structurally sound and sealed shipping containers, within the hazardous materials storage area. Hazardous waste materials shall be stored in appropriate and clearly marked containers and segregated from other non-waste materials. Secondary containment shall be provided for all waste materials in the hazardous materials storage area and shall consist of commercially available spill pallets. Additionally, all hazardous waste materials shall be disposed of in accordance with federal, state, and municipal regulations. Hazardous waste materials shall not be disposed of into the on-site dumpsters. All personnel shall be instructed regarding proper procedures for hazardous waste disposal. Notices that state these procedures shall be posted in the office trailer and the individual who manages day-to-day site operations shall be responsible for seeing that these procedures are followed. Implementation Shipping containers used to store hazardous waste materials shall be installed once the site materials storage area has been installed. Maintenance Requirements The hazardous waste material storage areas shall be inspected weekly and after storm events. The storage areas shall be kept clean, well organized, and equipped with ample cleanup supplies as appropriate for the materials being stored. Material safety data sheets, material inventory, and emergency contact numbers shall be maintained in the office trailer. Design Specifications For more information, see plans and specifications. 5.5.5 Construction and Domestic Waste General  Provide waste containers (e.g., dumpster, trash receptacle) of sufficient size and number to contain construction and domestic wastes: o For waste containers with lids, keep waste container lids closed when not in use, and close lids at the end of the business day and during storm events. For waste containers without lids, provide either (1) cover (e.g., a tarp, plastic sheeting, temporary roof) to minimize exposure of wastes to precipitation, or (2) a similarly effective means designed to minimize the discharge of pollutants (e.g., secondary containment). o On business days, clean up and dispose of waste in designated waste containers; and o Clean up immediately if containers overflow, and if there is litter elsewhere on the site from escaped trash.  If there are wastes that are subject to the exception in Part 2.3.3.e.ii, describe the specific wastes that will be stored on your site. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 34 Specific Pollution Prevention Practices Solid or Construction Waste Disposal Description: All waste materials shall be collected and disposed of into metal trash dumpsters or enclosed trash containers in the materials storage area. Dumpsters shall have a secure watertight lid, be placed away from stormwater conveyances and drains, and meet all federal, state, and municipal regulations. Only trash and construction debris from the site shall be deposited in the dumpster. No construction materials shall be buried on-site unless authorized by a program for recycling/beneficial use. All personnel shall be instructed regarding the correct disposal of trash and construction debris. Notices that state these practices shall be posted in the office trailer and the individual who manages day-today site operations shall be responsible for seeing that these practices are followed. Implementation Trash dumpsters shall be installed once the materials storage area has been established. Maintenance Requirements The dumpsters shall be inspected weekly and immediately after storm events. The dumpsters shall be emptied weekly and taken to an approved landfill or recycling facility. If trash and construction debris are exceeding the dumpsters’ capacity, the dumpsters shall be emptied more frequently. Waste container lids shall be closed when not in use and at the end of the business day. For waste containers that do not have lids, provide cover or a similarly effective means to minimize the discharge of pollutants. Design Specifications For more information, see plans and specifications. Recycling Description: Wood pallets, cardboard boxes, and other recyclable construction scraps shall be disposed of in a designated dumpster for recycling. The dumpster shall have a secure watertight lid, be placed away from stormwater conveyances and drains and meet all local and state solid- waste management regulations. Only solid recyclable construction scraps from the site shall be deposited in the dumpster. All personnel shall be instructed regarding the correct procedure for disposal of recyclable construction scraps. Notices that state these procedures shall be posted in the office trailer, and the individual who manages day-to-day site operations shall be responsible for seeing that these procedures are followed. Implementation Designated recycling dumpsters shall be installed once the area has been established. Maintenance Requirements The recycling dumpster shall be inspected weekly and immediately after storm events. The recycling dumpster shall be emptied weekly and taken to an approved recycling center. If recyclable construction wastes are exceeding the dumpsters’ capacity, the dumpsters shall be emptied more frequently. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 35 Recycling Design Specifications For more information, see plans and specifications. 5.5.6 Sanitary Waste General  Temporary sanitary facilities (portable toilets) will be positioned so they are secure and will not be tipped or knocked over, and will be located away from receiving waters, storm drain inlets, and constructed or natural site drainage features. Specific Pollution Prevention Practices Temporary Sanitary Facilities Description: Temporary sanitary facilities (portable toilets) shall be provided at the site throughout the construction phase. The portable toilets shall be located in the staging area, away from concentrated flow paths and traffic flow. Implementation The portable toilets shall be brought to the site once the staging area has been established. Maintenance Requirements All sanitary waste shall be collected from the portable facilities on a regular basis. The portable toilets shall be inspected weekly for evidence of leaking holding tanks. Toilets with leaking holding tanks shall be removed from the site and replaced with new portable toilets. Design Specifications For more information, see plans and specifications. 5.6 WASHING OF APPLICATORS AND CONTAINERS USED FOR STUCCO, PAINT, CONCRETE, FORM RELEASE OILS, CUTTING COMPOUNDS, OR OTHER MATERIALS General  Direct wash water into a leak-proof container or leak-proof and lined pit designed so no overflows can occur due to inadequate sizing or precipitation;  Handle washout or cleanout wastes as follows: o For liquid wastes:  Do not dump liquid wastes or allow them to enter into constructed or natural site drainage features, storm inlets, or receiving waters;  Do not allow liquid wastes to be disposed of through infiltration or to otherwise be disposed of on the ground;  Comply with applicable State, Tribal, or local requirements for disposal o Remove and dispose of hardened concrete waste consistent with your handling o of other construction wastes in CGP Part 2.3.3e; and  Locate any washout or cleanout activities as far away as possible from receiving waters, constructed or natural site drainage features, and storm drain inlets, and, to the extent DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 36 feasible, designate areas to be used for these activities and conduct such activities only in these areas. Specific Pollution Prevention Practices Concrete Washout Description: A designated temporary, above-grade concrete washout area shall be constructed. The temporary concrete washout area shall be constructed with a recommended minimum length and minimum width of 10 feet, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. The washout area shall be lined with plastic sheeting at least 10 mils thick and free of any holes or tears. Signs shall be posted marking the location of the washout area to ensure that concrete equipment operators use the proper facility. Concrete pours shall not be conducted during or before an anticipated storm event. Concrete mixer trucks and chutes shall be washed in the designated area or concrete wastes shall be properly disposed of off-site. When the temporary washout area is no longer needed for the construction project, the hardened concrete and materials used to construct the area shall be removed and disposed of according to the maintenance section below, and the area shall be stabilized. Implementation The washout area shall be constructed before concrete pours occur at the site. Maintenance Requirements The washout areas shall be inspected daily to ensure that all concrete washing is being discharged into the washout area, no leaks or tears are present, and to identify when concrete wastes need to be removed. The washout areas shall be cleaned out once the area is filled to 75 percent of the holding capacity. Once the area’s holding capacity has been reached, the concrete wastes shall be allowed to harden; the concrete shall be broken up, removed, and taken to an approved landfill for disposal or recycled on-site or off-site in accordance with applicable laws. The plastic sheeting shall be replaced if tears occur during removal of concrete wastes from the washout area. Design Specifications 1. Temporary concrete washout type Above Grade shall be constructed as shown above, with a recommended minimum length and minimum width of 10 feet. 2. The washout shall be a minimum of 50 feet from storm drain inlets. 3. Plastic lining shall be free of holes, tears, or other defects that compromise the impermeability of the material. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 37 Applicators, Containers, and Paint Washout Description: A designated temporary, above-grade washout area shall be constructed as needed for the washout and cleanout of stucco, paint, or other non-hazardous construction materials. The temporary washout area shall be a leak-proof container with sufficient volume to contain all liquid and waste generated by washout operations. The temporary washout shall be sited outside of all buffer zones. Implementation The washout area shall be constructed as needed. Maintenance Requirements The washout areas shall be inspected daily to ensure that all washing is being discharged into the washout area, no leaks or tears are present, and to identify when wastes need to be removed. The washout areas shall be cleaned out once the area is filled to 75 percent of the holding capacity. Washout wastes shall be handled as follows: For Liquid Wastes: • Do not dump liquid wastes or allow them to enter into constructed or natural site drainage features, storm inlets, or receiving waters; • Do not allow liquid wastes to be disposed of through infiltration or to otherwise be disposed of on the ground; • Comply with applicable State, Tribal, or local requirements for disposal. Design Specifications For more information, see plans and specifications. 5.7 APPLICATION OF FERTILIZERS General  Apply at a rate and in amounts consistent with manufacturer’s specifications, or document in the SWPPP departures from the manufacturer specifications where appropriate;  Apply at the appropriate time of year for your location, and preferably timed to coincide as closely as possible to the period of maximum vegetation uptake and growth;  Avoid applying before heavy rains that could cause excess nutrients to be discharged;  Never apply to frozen ground;  Never apply to constructed or natural site drainage features; and  Follow all other Federal, State, Tribal, and local requirements regarding fertilizer application. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Pollution Prevention Controls 38 Specific Pollution Prevention Practices Fertilizer Discharge Restrictions Description: Discharges from fertilizers containing nitrogen and phosphorus shall be minimized. Fertilizers shall be applied at rates and amounts consistent with the manufacture’s specification, and shall at no time exceed local, state, or federal specifications. See project landscape specifications for acceptable fertilizers that can be used for the project. Implementation Fertilizers shall be applied at an appropriate time of year, timed to coincide as closely as possible to the period of maximum vegetation uptake and growth. Fertilizers shall be applied at a rate and in amounts consistent with manufacturer’s specifications. Avoid applying fertilizers before heavy rains. Do not apply fertilizers to frozen ground or stormwater conveyance channels flowing with water. Maintenance Requirements Design Specifications For more information, see plans and specifications. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Turbidity Benchmark Monitoring for Dewatering Discharges 39 6.0 INSPECTION, MAINTENANCE, AND CORRECTIVE ACTION 6.1 INSPECTION PERSONNEL AND PROCEDURES Site Inspection Schedule Select the inspection frequency(ies) that applies, based on CGP Parts 4.2, 4.3, or 4.4 Increased Frequency (if applicable): For areas of sites discharging to sediment or nutrient-impaired waters or to waters designated as Tier 2, Tier 2.5, or Tier 3 ☒ Every 7 days and within 24 hours of either:  A storm event that produces 0.25 inches or more of rain within a 24-hour period, or  A discharge caused by snowmelt from a storm event that produces 3.25 inches or more of snow within a 24-hour period. Reduced Frequency (if applicable) For stabilized areas ☐ Twice during first month, no more than 14 calendar days apart; then once per month after first month until permit coverage is terminated consistent with Part 9 in any area of your site where the stabilization steps in 2.2.14.a have been completed.  For frozen conditions where construction activities are being conducted ☐ Once per month Insert beginning and ending dates of frozen conditions on your site:  Beginning date of frozen conditions: Click or tap to enter a date.  Ending date of frozen conditions: Click or tap to enter a date. For frozen conditions where construction activities are suspended ☐ Inspections are temporarily suspended Insert beginning and ending dates of frozen conditions on your site:  Beginning date of frozen conditions: Click or tap to enter a date.  Ending date of frozen conditions: Click or tap to enter a date. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Turbidity Benchmark Monitoring for Dewatering Discharges 40 Dewatering Inspection Schedule Select the inspection frequency that applies based on CGP Part 4.3.2 Dewatering Inspection ☒ Once per day on which the discharge of dewatering water occurs. Rain Gauge Location (if applicable) TBD Inspection Report Forms Inspection Report Forms are in Appendix D of this SWPPP. (Note: EPA has developed a sample inspection form that CGP operators can use. The form is available at https://www.epa.gov/npdes/stormwater-discharges-construction- activities#resources) 6.2 CORRECTIVE ACTION The corrective action log describes repairs, replacements, and maintenance of BMPs undertaken as a result of the inspections and maintenance procedures. Additionally, remedies of permit violations and clean and proper disposal of spills, releases, or other deposits should be recorded. Conditions Triggering Corrective Action: 1. A stormwater control needs a significant repair or a new or replacement control is needed, or, in accordance with CGP Part 2.1.4c, you find it necessary to repeatedly (i.e., 3 or more times) conduct the same routine maintenance fix to the same control at the same location (unless you document in your inspection report under CGP Part 4.7.1c that the specific reoccurrence of this same problem should still be addressed as a routine maintenance fix under CGP Part 2.1.4); 2. A stormwater control necessary to comply with the requirements of this permit was never installed, or was installed incorrectly; 3. The site’s discharges are not meeting applicable water quality standards; 4. A prohibited discharge has occurred; 5. During discharge from site dewatering activities: a. The weekly average of the turbidity monitoring results exceeds the 50 NTU benchmark (or alternate benchmark if approved by EPA pursuant to CGP Part 3.3.2b); or b. The observation of the presence of any of the following at the point of discharge to a receiving water flowing through or immediately adjacent to DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Turbidity Benchmark Monitoring for Dewatering Discharges 41 the site and/or to constructed or natural site drainage features or storm drain inlets: i. A sediment plume, suspended solids, unusual color, presence of odor, decreased clarity, or presence of foam; and/or ii. A visible sheen on the water surface or visible oily deposits on the bottom or shoreline of the receiving water If responding to any of the first four triggering conditions listed above, the operator must: 1. Immediately take all reasonable steps to address the condition, including cleaning up any contaminated surfaces so the material will not discharge in subsequent storm events; and 2. When the problem does not require a new or replacement control or significant repair, the corrective action must be completed by the close of the next business day; or 3. When the problem requires a new or replacement control or significant repair, install the new or modified control and make it operational, or complete the repair, by no later than seven (7) calendar days from the time of discovery. If it is infeasible to complete the installation or repair within seven (7) calendar days, you must document in your records why it is infeasible to complete the installation or repair within the 7-day timeframe and document your schedule for installing the stormwater control(s) and making it operational as soon as feasible after the 7-day timeframe. Where these actions result in changes to any of the stormwater controls or procedures documented in your SWPPP, you must modify your SWPPP accordingly within seven (7) calendar days of completing this work. If a corrective action is in response to either of the triggering conditions related to site dewatering activities, the operator must: 1. Immediately take all reasonable steps to minimize or prevent the discharge of pollutants until a solution can be implemented, including shutting off the dewatering discharge as soon as possible depending on the severity of the condition taking safety considerations into account; 2. Determine whether the dewatering controls are operating effectively and whether they are causing the conditions; and 3. Make any necessary adjustments, repairs, or replacements to the dewatering controls to lower the turbidity levels below the benchmark or remove the visible plume or sheen. When these steps have been completed and any necessary changes have been made, discharging from the dewatering activities may resume. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Turbidity Benchmark Monitoring for Dewatering Discharges 42 Personnel Responsible for Corrective Actions TBD Corrective Action Logs Corrective Action Forms and the Corrective Action Logs are in Appendix E of this SWPPP. (Note: EPA has developed a sample corrective action log that CGP operators can use. The form is available at https://www.epa.gov/npdes/stormwater-discharges-construction- activities#resources) 6.3 DELEGATION OF AUTHORITY Duly Authorized Representative(s) or Position(s): TBD DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Record Keeping and Training 43 7.0 RECORDKEEPING AND TRAINING 7.1 RECORDKEEPING A copy of the SWPPP, along with all inspection reports and corrective action logs are required to be stored at an accessible location at the site, and shall be made available upon request of the EPA, or state or local agency approving stormwater management plans. If an on-site location is unavailable to keep the SWPPP when no personnel are present, notice of the plan’s location must be posted near the main entrance of your construction site. The SWPPP may be prepared, signed, and kept electronically, rather than in paper form, if the records are: (a) in a format that can be read in a similar manner as a paper record; (b) legally dependable with no less evidentiary value than their paper equivalent; and (c) immediately accessible to the inspector during an inspection to the same extent as a paper copy stored at the site would be, if the records were stored in paper form. The following records shall be kept at the project site (or posted location) and shall be available for inspectors to review. These records shall be retained for a minimum period of at least 3 years after the permit is terminated. In Appendix I – Grading and Stabilization Activities Log, record (1) the date(s) when major grading activities occur, (2) date(s) when construction activities temporarily or permanently cease on a portion of the site, and (3) date(s) when an area is either temporarily or permanently stabilized. 7.2 LOG OF CHANGES TO THE SWPPP The log of changes to the SWPPP is maintained in Appendix G and includes additions of new BMPs, replacement of failed BMPs, significant changes in the activities or their timing on the project, changes in personnel, changes in inspection and maintenance procedures and update to site plans. 7.3 GENERAL TRAINING REQUIREMENTS FOR STORMWATER TEAM MEMBERS Prior to the commencement of construction activities, all persons assigned to the stormwater team must understand the requirements of the CGP and their specific responsibilities with respect to those requirements, including the following related to the scope of their job duties: 1. The permit requirements and deadlines associated with installation, maintenance, and removal of stormwater controls, as well as site stabilization; 2. The location of all stormwater controls on the site required by the CGP and how they are to be maintained; 3. The proper procedures to follow with respect to the CGP’s pollution prevention requirements; and DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Record Keeping and Training 44 4. When and how to conduct inspections, record applicable findings, and take corrective actions. training on the pollution prevention measures outlined in this SWPPP shall be provided to staff and subcontractors. maintained in Appendix G and includes additions of new BMPs, replacement 7.4 TRAINING REQUIREMENTS FOR PERSONS CONDUCTING INSPECTIONS For projects that obtain coverage under the 2022 CGP on or after February 17, 2023, any personnel conducting site inspections must, at a minimum, either:  Complete EPA’s construction inspection training program, or  Hold a current valid construction inspection certification or license from a program that, at a minimum, covers the following: (1) principles and practices of erosion and sediment control and pollution prevention practices at construction sites; (2) proper installation and maintenance of erosion and sediment controls and pollution prevention practices used at construction sites; and (3) performance of inspections, including the proper completion of required reports and documentation. Inspection certificates from the training program must be included in Appendix I. DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Certification and Notification 45 8.0 CERTIFICATION AND NOTIFICATION 8.1 SIGNATURE, PLAN REVIEW, AND MAKING PLANS AVAILABLE A copy of the SWPPP including a copy of the Construction General Permit, NOI, and acknowledgement letter from EPA shall be retained at the construction site (or other location easily accessible during normal business hours to EPA, a state, tribal or local agency approving sediment and erosion plans, grading plans, or storm water management plans; local government officials; the operator of a municipal separate storm sewer receiving discharges from the site; and representatives of the U.S. Fish and Wildlife Service or the National Marine Fisheries Service) from the date of commencement of construction activities to the date of final stabilization. A copy of the SWPPP shall be available at a central location on-site for the use of all those identified as having responsibilities under the SWPPP. If an on-site location is unavailable to store the SWPPP when no personnel are present, notice of the plan’s location shall be posted near the main entrance at the construction site. 8.2 NOTICE OF PERMIT COVERAGE A sign must be posted at a safe, publicly accessible location in close proximity to the construction site detailing the permit coverage. The notice must be located so that it is visible from the public road that is nearest to the active part of the construction site, and it must use a font large enough to be readily viewed from a public right-of-way. At a minimum, the notice must include:  The NPDES Permit Tracking Number and the EPA webpage where a copy of the NOI can be found (https://permitsearch.epa.gov/epermit-search/ui/search)),  A contact name and phone number for obtaining additional construction site information,  The Uniform Resource Locator (URL) for the SWPPP (if available), or the following statement: “If you would like to obtain a copy of the Stormwater Pollution Prevention Plan (SWPPP) for this site, contact the EPA Regional 1 Office at (617) 918-1038,  The following statement “If you observe indicators of stormwater pollutants in the discharge or in the receiving waterbody, contact the EPA through the following website: https://www.epa.gov/enforcement/report-environmental-violations.” DRAFT307 Main Street DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts Certification and Notification 46 8.3 OPERATOR CERTIFICATION I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I have no personal knowledge that the information submitted is other than true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Name: Title: Signature: Date: DRAFT 9.0 SWPPP APPENDICES Attach the following documentation to the SWPPP: Appendix A – Site Plans Appendix B – Copy of 2022 CGP Appendix C – NOI and EPA Authorization Email Appendix D – Site Inspection Form and Dewatering Inspection Form (if applicable) Appendix E – Corrective Action Log Appendix F – SWPPP Amendment Log Appendix G – Subcontractor Certifications/Agreements Appendix H – Grading and Stabilization Activities Log Appendix I – Training Documentation Appendix J – Delegation of Authority Appendix K – Endangered Species Documentation Appendix L – Historic Preservation Documentation Appendix M – Rainfall Gauge Recording Appendix N – Turbidity Monitoring Sampling Documentation Appendix O – Temporary Sediment Basin Sizing Calculation DRAFT Appendix A Site Plans DRAFT Appendix B Copy of 2022 Construction General Permit (CGP) https://www.epa.gov/npdes/2022-construction-general-permit-cgp DRAFT Appendix C NOI and EPA Authorization Email DRAFT Appendix D Site and Dewatering Inspection Forms The following pages should be copied and completed for each inspection. All inspection forms should be compiled in a binder to prove compliance with this SWPPP. Further instructions and general tips on how to properly complete the site and dewatering inspection forms can be found in the templates that the EPA has developed. The templates are available at: https://www.epa.gov/npdes/construction-general-permit-resources-tools-and-templates DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 1 of 7 Section A – General Information (If necessary, complete additional inspection reports for each separate inspection location.) Inspector Information Inspector Name: Title: Company Name: Email: Address: Phone Number: Inspection Details Inspection Date: Inspection Location: Inspection Start Time: Inspection End Time: Current Phase of Construction: Weather Conditions During Inspection: Did you determine that any portion of your site was unsafe for inspection per CGP Part 4.5? ☐ Yes ☐ No If “Yes,” provide the following information: Location of unsafe conditions: The conditions that prevented you inspecting this location: Indicate the required inspection frequency: (Check all that apply. You may be subject to different inspection frequencies in different areas of the site.) Standard Frequency (CGP Part 4.2): ☐ At least once every 7 calendar days; OR ☐ Once every 14 calendar days and within 24 hours of the occurrence of either:  A storm event that produces 0.25 inches or more of rain within a 24-hour period, or  A snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period Increased Frequency (CGP Part 4.3.1) (If site discharges to sediment or nutrient-impaired waters or to waters designated as Tier 2, Tier 2.5, or Tier 3): ☐ Once every 7 calendar days and within 24 hours of the occurrence of either:  A storm event that produces 0.25 inches or more of rain within a 24-hour period, or  A snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 2 of 7 Reduced Frequency (CGP Part 4.4): ☐ For stabilized areas: Twice during first month, no more than 14 calendar days apart; then once per month after first month until permit coverage is terminated ☐ For stabilized areas on “linear construction sites”: Twice during first month, no more than 14 calendar days apart; then once more within 24 hours of the occurrence of either:  A storm event that produces 0.25 inches or more of rain within a 24-hour period, or  A snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period ☐ For arid, semi-arid, or drought-stricken areas during seasonally dry periods or during drought: Once per month and within 24 hours of the occurrence of either:  A storm event that produces 0.25 inches or more of rain within a 24-hour period, or  A snowmelt discharge from a storm event that produces 3.25 inches or more of snow within a 24-hour period ☐ For frozen conditions where construction activities are being conducted: Once per month Was this inspection triggered by a storm event producing 0.25 inches or more of rain within a 24-hour period? ☐ Yes ☐ No If “Yes,” how did you determine whether the storm produced 0.25 inches or more of rain? ☐ On-site rain gauge ☐ Weather station representative of site. Weather station location: Total rainfall amount that triggered the inspection (inches): Was this inspection triggered by a snowmelt discharge from a storm event producing 3.25 inches or more of snow within a 24-hour period? ☐ Yes ☐ No If “Yes,” how did you determine whether the storm produced 3.25 inches or more of snow? ☐ On-site rain gauge ☐ Weather station representative of site. Weather station location: Total snowfall amount that triggered the inspection (inches): DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 3 of 7 Section B – Condition and Effectiveness of Erosion and Sediment (E&S) Controls (CGP Part 2.2) (Insert additional rows if needed) Type and Location of E&S Control Conditions Requiring Routine Maintenance?1 If “Yes,” How Many Times (Including This Occurrence) Has This Condition Been Identified? Conditions Requiring Corrective Action?2, 3 Date on Which Condition First Observed (If Applicable)? Description of Conditions Observed 1. ☐ Yes ☐ No ☐ Yes ☐ No 2. ☐ Yes ☐ No ☐ Yes ☐ No 3. ☐ Yes ☐ No ☐ Yes ☐ No 4. ☐ Yes ☐ No ☐ Yes ☐ No 5. ☐ Yes ☐ No ☐ Yes ☐ No If the same routine maintenance was found to be necessary three or more times for the same control at the same location (including this occurrence), follow the corrective action requirements and record the required information in your corrective action log, or describe here why you believe the specific condition should still be addressed as routine maintenance: 1 Routine maintenance includes minor repairs or other upkeep performed to ensure that the site’s stormwater controls remain in effective operating condition, not including significant repairs or the need to install a new or replacement control. Routine maintenance is also required for specific conditions: (1) for perimeter controls, whenever sediment has accumulated to half or more the above-ground height of the control (CGP Part 2.2.3.c.i); (2) where sediment has been tracked-out from the site onto paved roads, sidewalks, or other paved areas (CGP Part 2.2.4.d); (3) for inlet protection measures, when sediment accumulates, the filter becomes clogged, and/or performance is compromised (CGP Part 2.2.10.b); and (4) for sediment basins, as necessary to maintain at least half of the design capacity of the basin (CGP Part 2.2.12.f) 2 Corrective actions are triggered only for specific conditions (CGP Part 5.1): 1. A stormwater control needs a significant repair or a new or replacement control is needed, or, in accordance with Part 2.1.4.c, you find it necessary to repeatedly (i.e., three (3) or more times) conduct the same routine maintenance fix to the same control at the same location (unless you document in your inspection report under Part 4.7.1.c that the specific reoccurrence of this same problem should still be addressed as a routine maintenance fix under 2.1.4); or 2. A stormwater control necessary to comply with the requirements of this permit was never installed, or was installed incorrectly; or 3. Your discharges are not meeting applicable water quality standards; or 4. A prohibited discharge has occurred (see CGP Part 1.3); or 5. During the discharge from site dewatering activities: a. The weekly average of your turbidity monitoring results exceeds the 50 NTU benchmark (or alternate benchmark if approved by EPA pursuant to Part 3.3.2.b); or b. You observe or you are informed by EPA, State, or local authorities of the presence of the conditions specified in Part 4.6.3.e. 3 If a condition on your site requires a corrective action, you must also fill out a corrective action log found at https://www.epa.gov/npdes/construction-general-permit-resources-tools-and-templates. See CGP Part 5.4 for more information. DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 4 of 7 Section C – Condition and Effectiveness of Pollution Prevention (P2) Practices and Controls (CGP Part 2.3) (Insert additional rows if needed) Type and Location of P2 Practices and Controls Conditions Requiring Routine Maintenance?1 If “Yes,” How Many Times (Including This Occurrence) Has This Condition Been Identified? Conditions Requiring Corrective Action?2, 3 Date on Which Condition First Observed (If Applicable)? Description of Conditions Observed 1. ☐ Yes ☐ No ☐ Yes ☐ No 2. ☐ Yes ☐ No ☐ Yes ☐ No 3. ☐ Yes ☐ No ☐ Yes ☐ No 4. ☐ Yes ☐ No ☐ Yes ☐ No 5. ☐ Yes ☐ No ☐ Yes ☐ No If the same routine maintenance was found to be necessary three or more times for the same control at the same location (including this occurrence), follow the corrective action requirements and record the required information in your corrective action log, or describe here why you believe the specific condition should still be addressed as routine maintenance: DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 5 of 7 Section D – Stabilization of Exposed Soil (CGP Part 2.2.14) (Insert additional rows if needed) Specific Location That Has Been or Will Be Stabilized Stabilization Method and Applicable Deadline Stabilization Initiated? Final Stabilization Criteria Met? Final Stabilization Photos Taken? Notes 1. ☐ Yes ☐ No If “Yes,” date initiated: ☐ Yes ☐ No If “Yes,” date criteria met: ☐ Yes ☐ No 2. ☐ Yes ☐ No If “Yes,” date initiated: ☐ Yes ☐ No If “Yes,” date criteria met: ☐ Yes ☐ No 3. ☐ Yes ☐ No If “Yes,” date initiated: ☐ Yes ☐ No If “Yes,” date criteria met: ☐ Yes ☐ No 4. ☐ Yes ☐ No If “Yes,” date initiated: ☐ Yes ☐ No If “Yes,” date criteria met: ☐ Yes ☐ No 5. ☐ Yes ☐ No If “Yes,” date initiated: ☐ Yes ☐ No If “Yes,” date criteria met: ☐ Yes ☐ No DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 6 of 7 4 If a dewatering discharge was occurring, you must conduct a dewatering inspection pursuant to CGP Part 4.3.2 and complete a separate dewatering inspection report. Section E – Description of Discharges (CGP Part 4.6.2) (Insert additional rows if needed) Was a discharge (not including dewatering) occurring from any part of your site at the time of the inspection?4 ☐ Yes ☐ No If “Yes,” for each point of discharge, document the following:  The visual quality of the discharge.  The characteristics of the discharge, including color; odor; floating, settled, or suspended solids; foam; oil sheen; and other indicators of stormwater pollutants.  Signs of the above pollutant characteristics that are visible from your site and attributable to your discharge in receiving waters or in other constructed or natural site drainage features. Discharge Location Observations 1. 2. 3. 4. 5. DRAFT2022 Construction General Permit Site Inspection Report Project Name: _______________________________________ NPDES ID Number: ________________________________ Page 7 of 7 Section F – Signature and Certification (CGP Part 4.7.2) “I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information contained therein. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information contained is, to the best of my knowledge and belief, true, accurate, and complete. I have no personal knowledge that the information submitted is other than true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.” MANDATORY: Signature of Operator or “Duly Authorized Representative:” Signature: Date: Printed Name: Affiliation: OPTIONAL: Signature of Contractor or Subcontractor Signature: Date: Printed Name: Affiliation: DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 SWPPP PHOTOGRAPHIC LOG Client Name: Photo Location: Project No: Photo No: 1 Date: Description: Client Name: Photo Location: Project No: Photo No: 2 Date: Description: DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 Client Name: Photo Location: Project No: Photo No: 3 Date: Description: Client Name: Photo Location: Project No: Photo No: 4 Date: Description: DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 Client Name: Photo Location: Project No: Photo No: 5 Date: Description: Client Name: Photo Location: Project No: Photo No: 6 Date: Description: DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 Client Name: Photo Location: Project No: Photo No: 7 Date: Description: Client Name: Photo Location: Project No: Photo No: 8 Date: Description: DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 Section A – Dewatering Discharges (CGP Part 4.6.3) Complete this section within 24 hours of completing the inspection. (If necessary, complete additional inspection reports for each separate inspection location.) Inspector Information Inspector Name: Title: Company Name: Email: Address: Phone Number: Inspection Details Inspection Date: Inspection Location: Discharge Start Time: Discharge End Time: Rate of Discharge (gallons per day): Corrective Action Required?1 ☐ Yes ☐ No Describe Indicators of Pollutant Discharge at Point of Dewatering Discharge:1 Attach Photographs of: 1. Dewatering water prior to treatment by a dewatering control(s) and the final discharge after treatment; and 2. Dewatering control(s); and 3. Point of discharge to any receiving waters flowing through or immediately adjacent to the site and/or to constructed or natural site drainage features, storm drain inlets, and other conveyances to receiving waters. 1 If you observe any of the following indicators of pollutant discharge, you are required to take corrective action under Part 5.1.5.b:  a sediment plume, suspended solids, unusual color, presence of odor, decreased clarity, or presence of foam; or  a visible sheen on the water surface or visible oily deposits on the bottom or shoreline of the receiving water. DRAFTProject Name DRAFT Stormwater Pollution Prevention Plan (SWPPP) Hyannis, Massachusetts 000000RP000 Section B – Signature and Certification (CGP Part 4.7.2) “I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information contained therein. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information contained is, to the best of my knowledge and belief, true, accurate, and complete. I have no personal knowledge that the information submitted is other than true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.” MANDATORY: Signature of Operator or “Duly Authorized Representative:” Signature: Date: Printed Name: Affiliation: OPTIONAL: Signature of Contractor or Subcontractor Signature: Date: Printed Name: Affiliation: DRAFT Appendix E Corrective Action Log Further instructions and general tips on how to properly complete the corrective action log can be found in the template that the EPA has developed. The template is available at: https://www.epa.gov/npdes/construction-general-permit-resources-tools-and-templates DRAFT 2022 CGP Corrective Action Log Project Name: ______________________________________________ NPDES ID Number: __________________________________________ Section A – Individual Completing this Log Name: Title: Company Name: Email: Address: Phone Number: Section B – Details of the Problem (CGP Part 5.4.1.a) Complete this section within 24 hours of discovering the condition that triggered corrective action. Date problem was first identified: Time problem was first identified: What site conditions triggered this corrective action? (Check the box that applies. See instructions for a description of each triggering condition (1 thru 6).) ☐ 1 ☐ 2 ☐ 3 ☐ 4 ☐ 5a ☐ 5b ☐ 6 Specific location where problem identified: Provide a description of the specific condition that triggered the need for corrective action and the cause (if identifiable): Section C – Corrective Action Completion (CGP Part 5.4.1.b) Complete this section within 24 hours after completing the corrective action. For site condition # 1, 2, 3, 4, or 6 (those not related to a dewatering discharge) confirm that you met the following deadlines (CGP Part 5.2.1): ☐ Immediately took all reasonable steps to address the condition, including cleaning up any contaminated surfaces so the material will not discharge in subsequent storm events. AND ☐ Completed corrective action by the close of the next business day, unless a new or replacement control, or significant repair, was required. OR ☐ Completed corrective action within seven (7) calendar days from the time of discovery because a new or replacement control, or significant repair, was necessary to complete the installation of the new or modified control or complete the repair. OR ☐ It was infeasible to complete the installation or repair within 7 calendar days from the time of discovery. Provide the following additional information: Explain why 7 calendar days was infeasible to complete the installation or repair: Provide your schedule for installing the stormwater control and making it operational as soon as feasible after the 7 calendar days: For site condition # 5a, 5b, or 6 (those related to a dewatering discharge), confirm that you met the following deadlines: ☐ Immediately took all reasonable steps to minimize or prevent the discharge of pollutants until a solution could be implemented, including shutting off the dewatering discharge as soon as possible depending on the severity of the condition taking safety considerations into account. DRAFT ☐ Determined whether the dewatering controls were operating effectively and whether they were causing the conditions. ☐ Made any necessary adjustments, repairs, or replacements to the dewatering controls to lower the turbidity levels below the benchmark or remove the visible plume or sheen. Describe any modification(s) made as part of corrective action: (Insert additional rows below if applicable) Date of completion: SWPPP update necessary? If yes, date SWPPP was updated: 1. ☐ Yes ☐ No 2. ☐ Yes ☐ No Section D - Signature and Certification (CGP Part 5.4.2) “I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information contained therein. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information contained is, to the best of my knowledge and belief, true, accurate, and complete. I have no personal knowledge that the information submitted is other than true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations.” MANDATORY: Signature of Operator or “Duly Authorized Representative:” Signature: Date: Printed Name: Affiliation: OPTIONAL: Signature of Contractor or Subcontractor Signature: Date: Printed Name: Affiliation: DRAFT Appendix F SWPPP Amendment Log The SWPPP, including the site plans, shall be amended whenever there is a change in design, construction, operation, or maintenance at the construction site that has or could have a significant effect on the discharge of pollutants to the waters of the United States that has not been previously addressed in the SWPPP. The SWPPP shall be amended if during inspections or investigations by site staff, or by local, state, tribal or federal officials, it is determined that the SWPPP is ineffective in eliminating or significantly minimizing pollutants in storm water discharges from the construction site. DRAFT SWPPP Amendment Log No. Description of the Amendment Date of Amendment Amendment Prepared by [Name(s) and Title] DRAFT Appendix G Subcontractor Certifications/Agreements DRAFT Sample Subcontractor Certifications/Agreements SUBCONTRACTOR CERTIFICATION STORMWATER POLLUTION PREVENTION PLAN Project Number: Project Title: Operator(s): As a subcontractor, you are required to comply with the Stormwater Pollution Prevention Plan (SWPPP) for any work that you perform on-site. Any person or group who violates any condition of the SWPPP may be subject to substantial penalties or loss of contract. You are encouraged to advise each of your employees working on this project of the requirements of the SWPPP. A copy of the SWPPP is available for your review at the office trailer. Each subcontractor engaged in activities at the construction site that could impact stormwater must be identified and sign the following certification statement: I certify under the penalty of law that I have read and understand the terms and conditions of the SWPPP for the above designated project and agree to follow the practices described in the SWPPP. This certification is hereby signed in reference to the above named project: Company: Address: Telephone Number: Type of construction service to be provided: Signature: Title: Date: DRAFT Appendix H Grading and Stabilization Activities Log Site Plans in Appendix A should be annotated to indicate areas where final stabilization has been accomplished and no further construction-phase permit requirements apply. DRAFT Grading and Stabilization Activities Log The following records are to be kept by each Site Operator throughout the construction period and maintained in the SWPPP. Insert additional documentation for record keeping as necessary. Date Grading Activity Initiated Description of Grading Activity Description of Stabilization Measure and Location Date Grading Activity Ceased (Indicate Temporary or Permanent) Date When Stabilization Measures Initiated INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE INSERT DATE INSERT DATE ☐ Temporary ☐ Permanent INSERT DATE DRAFT Appendix I Training Documentation DRAFT Training Log Date Training Topic Attendee Signature of Training Coordinator DRAFT Appendix J Delegation of Authority Form DRAFT Sample Delegation of Authority Form Delegation of Authority I, _______________________ (name), hereby designate the person or specifically described position below to be a duly authorized representative for the purpose of overseeing compliance with environmental requirements, including the EPA’s Construction General Permit (CGP), at the ____________________________________ construction site. The designee is authorized to sign any reports, stormwater pollution prevention plans and all other documents required by the permit. ________________________________________ (name of person or position) ________________________________________ (company) ________________________________________ (address) ________________________________________ (city, state, zip) ________________________________________ (phone) By signing this authorization, I confirm that I meet the requirements to make such a designation as set forth in Appendix G of EPA’s Construction General Permit (CGP), and that the designee above meets the definition of a “duly authorized representative” as set forth in Appendix G. I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Name: Company: Title: Signature: Date: DRAFT Appendix K Endangered Species Documentation DRAFT Appendix L Historic Preservation Documentation DRAFT Appendix M Rainfall Gauge Recording DRAFT Rainfall Gauge Recording Use the table below to record the rainfall gauge readings at the beginning and end of each work day. An example table follows. Month/Year Month/Year Month/Year Day Start time End time Day Start time End time Day Start time End time 1 1 1 2 2 2 3 3 3 4 4 4 5 5 5 6 6 6 7 7 7 8 8 8 9 9 9 10 10 10 11 11 11 12 12 12 13 13 13 14 14 14 15 15 15 16 16 16 17 17 17 18 18 18 19 19 19 20 20 20 21 21 21 22 22 22 23 23 23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 30 30 30 31 31 31 DRAFT Example Rainfall Gauge Recording April 2022 May 2022 June 2022 Day 7:00 am 4:400 pm Day 7:00 am 4:00 pm Day 7:00 am 4:00 pm 1 -- -- 1 0.2 0 1 0 0.4 2 -- -- 2 0 0 2 0 0 3 0 0 3 0.1 0.3 3 -- -- 4 0 0.3 4 0 0 4 -- -- 5 0 0 5 0 0 5 0 0 In this example (for only partial months), 0.25-inch rainfall inspections would have been conducted on April 4 and June 1. DRAFT Appendix N Turbidity Monitoring Sampling Documentation DRAFT Appendix O Temporary Sediment Basin Sizing Calculations