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HomeMy WebLinkAbout2024-10-07 Stormwater Report_reduced Prepared by: 349 Main Street - Route 28 West Yarmouth, MA 02649 STORMWATER REPORT TIDEWATER MOTOR LODGE 135 ROUTE 28 WEST YARMOUTH, MA NOVEMBER 2024 Owner/Applicant: HARI HOSPITALITY, INC. 135 Route 28 West Yarmouth, MA 02673 BSC Job Number: 50711.00 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA TABLE OF CONTENTS 1.0 PROJECT INFORMATION 1.01 PROJECT DESCRIPTION 1.02 PRE-DEVELOPMENT CONDITIONS 1.03 POST-DEVELOPMENT CONDITIONS 2.0 DRAINAGE SUMMARY 2.01 STORMWATER STANDARD 1 – NEW STORMWATER CONVEYANCES 2.02 STORMWATER STANDARD 2 – STORMWATER RUNOFF RATES 2.03 STORMWATER STANDARD 3 – GROUNDWATER RECHARGE 2.04 STORMWATER STANDARD 4 – TSS REMOVAL 2.05 STORMWATER STANDARD 5 – LUHPPL 2.06 STORMWATER STANDARD 6 – CRITICAL AREAS 2.07 STORMWATER STANDARD 7 – REDEVELOPMENT PROJECTS 2.08 STORMWATER STANDARD 8 – SEDIMENTATION & EROSION CONTROL PLAN 2.09 STORMWATER STANDARD 9 – LONG TERM O&M PLAN 2.10 STORMWATER STANDARD 10 – ILLICIT DISCHARGES 2.11 CONCLUSIONS 3.0 CONSTRUCTION PERIOD POLLUTION PREVENTION AND EROSION AND SEDIMENTATION CONTROL 4.0 LONG-TERM POLLUTION PREVENTION & OPERATION AND MAINTENANCE PLAN 5.0 HYDROLOGY CALCULATIONS 5.01 EXISTING WATERSHED PLAN 5.02 EXISTING HYDROLOGY CALCULATIONS (HYDROCAD™ PRINTOUTS) 5.03 PROPOSED WATERSHED PLAN 5.04 PROPOSED HYDROLOGY CALCULATIONS (HYDROCAD™ PRINTOUTS) 6.0 ADDITIONAL DRAINAGE CALCULATIONS 6.01 TSS REMOVAL CALCULATIONS 6.02 GROUNDWATER RECHARGE VOLUME CALCULATIONS 6.03 WATER QUALITY VOLUME CALCULATIONS 6.04 PIPE SIZING CALCULATIONS 6.05 WQU SIZING CALCULATIONS 6.06 ILLICIT DISCHARGE COMPLIANCE STATEMENT APPENDICES APPENDIX A – USGS LOCUS MAP APPENDIX B – FEMA MAP APPENDIX C – WEB SOIL SURVEY APPENDIX D – NOAA 14 PRECIPITATION TABLES APPENDIX E – STORMWATER CHECKLIST Stormwater Report Tidewater Motor Lodge West Yarmouth, MA SECTION 1.0 PROJECT INFORMATION Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 1.01 PROJECT DESCRIPTION Hari Hospitality, Inc. (The Applicant) is seeking to construct a 30’x30’ building overhang, concrete patio and a gravel walkway with paver stones in West Yarmouth, Massachusetts, hereinafter referred to as “the Project”. The total property area is approximately 3.92 acres and is located off Route 28 near the intersection with Baxter Avenue. The project is bounded on the north by Mill Pond, on the east by a privately owned inn and a wetland, on the west by Baxter Avenue, and bounded on the south by Gleason Avenue. The project consists of demolishing an existing shed and the construction of a 30’x30’ building overhang, a concrete patio, a gravel walkway with paver stones and a stormwater management system. A portion of the site is located within the 100-foot and 200-foot riverfront area. Due to the demolition of the existing shed, there will be an approximately 75 square foot decrease in impervious area within the 100-foot riverfront area. Due to the installation of the concrete patio, there is a 1,695 square foot increase to impervious area within the 200-foot riverfront area. However, by removing 798 square feet of concrete walkway, the net increase in impervious area within the 200-foot riverfront area is equal to 977 square feet. Riverfront mitigation is provided at a 2:1 ratio as required in 310 CMR 10.58(5)(g). 1.02 PRE-DEVELOPMENT CONDITIONS The existing site topography generally slopes southeast across the property towards the wetland located east of the property with slopes ranging from 0-19%. The current site is comprised of four buildings, an inground swimming pool, a large, paved parking area, and areas of vegetation. The primary soil classification identified by the NRCS Web Soil Survey is Carver coarse sand (252A), which accounts for the entire property and project area. Based on the soil classification identified, runoff calculations have been performed using curve numbers corresponding to Hydrologic Soil Group (HSG) A. The existing site consists of a series of leaching catch basins which capture the majority of stormwater runoff from the roof and parking area. South of the existing building located on the east edge of the property, there is a paved waterway which slopes down to a leaching catch basin. The paved waterway extends past the catch basin, allowing any overflow from the structure to sheet flow directly towards the wetland. A small portion of the site flows overland directly into the wetland east of the property. There are no proposed changes to any existing drainage features. 1.03 POST-DEVELOPMENT CONDITIONS The proposed stormwater management system has been designed in a manner that will meet or exceed the provisions of the Department of Environmental Protection (DEP) Stormwater Management Standards for a reconstruction project. Stormwater runoff from the proposed 30’x30’ (900 square feet) building overhang will be captured by a 4” polyvinyl chloride (PVC) roof drain, routing the runoff into the proposed infiltration system. In addition, a 48” diameter water quality unit at a low point in the lawn will capture any runoff from the concrete patio. This structure will remove 77% of total suspended solids prior to entering the underground infiltration system, exceeding the 44% TSS removal required by the Town of Yarmouth. This underground infiltration system provides recharge to groundwater and provides peak flow rate attenuation. The system has been designed to completely hold and infiltrate the 100-year, 24-hour storm event. Specifics of the project’s compliance with the Stormwater Standards are discussed in detail in the following sections. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA SECTION 2.0 DRAINAGE SUMMARY Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 2.01 Stormwater Standard 1 – New Stormwater Conveyances Per Massachusetts Stormwater Management Standard #1, no new outfalls may discharge untreated stormwater directly to or cause erosion in wetlands or waters of the Commonwealth. No new untreated stormwater discharges are proposed. 2.02 Stormwater Standard 2 – Stormwater Runoff Rates Watershed modeling was performed using HydroCAD Stormwater Modeling Software version 10.20, a computer aided design program that combines SCS runoff methodology with standard hydraulic calculations. A model of the site’s hydrology was developed for both pre- and post-development conditions to assess the effects of the proposed development on the project site and surrounding areas. Stormwater runoff was modeled using data from the NOAA 14 rainfall atlas. The following rainfall values have been used in our analysis and the NOAA 14 data is included in Appendix D: Storm Frequency NOAA 14 Rainfall (Inches) 2-year 3.38 10-year 4.93 25-year 5.89 50-year 6.62 100-year 7.38 The stormwater management system for the project has been designed such that the post-development conditions result in no increase to peak runoff rates off the property for the 2, 10, 25, 50, and 100-year, 24-hour storm events, as detailed in the table below. Peak Flow Discharge Rates Node DP1 – Flow to Catch Basins Storm Event Pre-Development Peak Discharge Rate (cfs) Post-Development Peak Discharge Rate (cfs) Change in Peak Discharge Rate (cfs) 2-Year 3.38 3.38 0.00 10-Year 6.59 6.59 0.00 25-Year 8.70 8.70 0.00 50-Year 10.33 10.33 0.00 100-Year 12.04 12.04 0.00 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Node DP2 – Flow Off-Site (North) Storm Event Pre-Development Peak Discharge Rate (cfs) Post-Development Peak Discharge Rate (cfs) Change in Peak Discharge Rate (cfs) 2-Year 2.16 2.16 0.00 10-Year 3.31 3.31 0.00 25-Year 4.02 4.02 0.00 50-Year 4.56 4.56 0.00 100-Year 5.12 5.12 0.00 Node DP3 – Flow Off-Site (Wetland) Storm Event Pre-Development Peak Discharge Rate (cfs) Post-Development Peak Discharge Rate (cfs) Change in Peak Discharge Rate (cfs) 2-Year 0.03 0.03 0.00 10-Year 0.41 0.38 -0.03 25-Year 0.91 0.85 -0.06 50-Year 1.35 1.27 -0.08 100-Year 1.87 1.76 -0.11 2.03 Stormwater Standard 3 – Groundwater Recharge Groundwater recharge is provided on site via an underground infiltration system beneath lawn northeast of the proposed building overhang. Overall, the project will result in no loss of annual recharge to groundwater as required by Standard 3. Refer to Section 6.0 of this Report for groundwater recharge information. 2.04 Stormwater Standard 4 – TSS Removal As a redevelopment, the Project stormwater management system will achieve a TSS removal equal to 80%, as required by the Town of Yarmouth. The proposed stormwater management system has been designed to provide treatment of runoff in order to reduce suspended solids prior to discharge off-site through the implementation of the following best management practices: · Underground Stormwater Infiltration Systems The water quality volume is defined as the runoff volume requiring TSS Removal for the site and is equal to 0.5-inches of runoff over the total impervious area of the post-development site. The required water quality volume for the project is provided in Section 6.0 of this Report. The underground infiltration system has been sized to treat the required water quality volume and calculations are included in Section 6.0 of this Report. A long-term pollution prevention plan complying with the requirements of Standard 4 is included in Section 4.0 of this Report. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 2.05 Stormwater Standard 5 – Land Uses with Higher Potential Pollutant Loads This standard is not applicable as the project site is not a land use with higher potential pollutant loads (LUHPPL). 2.06 Stormwater Standard 6 – Stormwater Discharges to a Critical Area This standard is not applicable as runoff from the project site does not discharge to a critical area. 2.07 Stormwater Standard 7 – Redevelopment Projects This project is a redevelopment and therefore is required to comply with the Stormwater Management Standards to the maximum extent practicable, however, this project has been designed to fully comply with the Stormwater Management Standards. 2.08 Stormwater Standard 8 – Sedimentation and Erosion Control Plan Erosion and sedimentation controls are shown on the Project Plans. Additionally, a Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan is included in Section 3.0 of this Report. 2.09 Stormwater Standard 9 – Long Term Operation and Maintenance Plan A Long-Term Operation and Maintenance Plan is included in Section 4.0 of this Report. 2.10 Stormwater Standard 10 – Illicit Discharges There are no known illicit discharges on the project site, and none are proposed. An illicit discharge compliance statement is included in Section 6.0 and will be signed by the Applicant prior to issuance of any permits. 2.11 Conclusion The project has been designed in accordance with DEP Stormwater Management Standards. Through the construction of the aforementioned stormwater systems, the project will provide peak rate attenuation, TSS removal and groundwater recharge. SECTION 3.0 CONSTRUCTION PERIOD POLLUTION PREVENTION AND EROSION AND SEDIMENTATION CONTROL PLAN Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 3.0 CONSTRUCTION PERIOD POLLUTION PREVENTION AND EROSION AND SEDIMENTATION CONTROL PLAN This Section specifies requirements and suggestions for implementation of a Stormwater Pollution Prevention Plan (SWPPP) for Tidewater Motor Lodge, in West Yarmouth, Massachusetts. The SWPPP shall be provided and maintained on-site by the Contractor(s) during all construction activities. The SWPPP shall be updated as required to reflect changes to construction activity. The stormwater pollution prevention measures contained in the SWPPP shall be at least the minimum required by Local Regulations. The Contractor shall provide additional measures to prevent pollution from stormwater discharges in compliance with the National Pollution Discharge Elimination System (NPDES) Phase II permit requirements and all other local, state and federal requirements. The SWPPP shall include provisions for, but not be limited to, the following: 1. Construction Trailers 2. Lay-down Areas 3. Equipment Storage Areas 4. Stockpile Areas 5. Disturbed Areas The Contractor shall NOT begin construction without submitting evidence that a NPDES Notice of Intent (NOI) governing the discharge of stormwater from the construction site for the entire construction period has been filed at least fourteen (14) days prior to construction. It is the Contractor's responsibility to complete and file the NOI, unless otherwise determined by the project team. The cost of any fines, construction delays and remedial actions resulting from the Contractor's failure to comply with all provisions of local regulations and Federal NPDES permit requirements shall be paid for by the Contractor at no additional cost to the Owner. As a requirement of the EPA’s NPDES permitting program, each Contractor and Subcontractor responsible for implementing and maintaining stormwater Best Management Practices shall execute a Contractor's Certification form. Erosion and Sedimentation Control The Contractor shall be solely responsible for erosion and sedimentation control at the site. The Contractor shall utilize a system of operations and all necessary erosion and sedimentation control measures, even if not specified herein or elsewhere, to minimize erosion damage at the site to prevent the migration of sediment into environmentally sensitive areas. Environmentally sensitive areas include all wetland resource areas within, and downstream of, the site, and those areas of the site that are not being altered. Erosion and sedimentation control shall be in accordance with this Section, the design drawings, and the following:  “National Pollutant Discharge Elimination System General Permit for Discharges from Construction Activities (EPA Construction General Permit February 16, 2017).  Massachusetts Stormwater Management Policy Handbook issued by the Massachusetts Department of Environmental Protection, January 2008.  Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas, A Guide for Planners, Designers and Municipal Officials, March 1997. The BMP's presented herein should be used as a guide for erosion and sedimentation control and are not intended to be considered specifications for construction. The most important BMP is maintaining a rapid construction process, resulting in prompt stabilization of surfaces, thereby reducing erosion potential. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Given the primacy of rapid construction, these guidelines have been designed to allow construction to progress with essentially no hindrance by the erosion control methods prescribed. These guidelines have also been designed with sufficient flexibility to allow the Contractor to modify the suggested methods as required to suit seasonal, atmospheric, and site-specific physical constraints. Another important BMP is the prevention of concentrated water flow. Sheet flow does not have the erosive potential of a concentrated rivulet. These guidelines recommend construction methods that allow localized erosion control and a system of construction, which inhibits the development of shallow concentrated flow. These BMP's shall be maintained throughout the construction process. CONTACT INFORMATION AND RESPONSIBLE PARTIES The following is a list of all project-associated parties: Owner Hari Hospitality, Inc. 135 Route 28 West Yarmouth, MA 02673 Contractor To be determined Environmental Consultant BSC Group, Inc. 803 Summer Street Boston, MA 02127 Contact: Brian G. Yergatian, P.E. Phone: (617) 896–4590 Email: byergatian@bscgroup.com Qualified SWPPP Inspectors To Be Determined 3.1 Procedural Conditions of the Construction General Permit (CGP) The following list outlines the Stormwater Responsibilities for all construction operators working on the Project. The operators below agree through a cooperative agreement to abide by the following conditions throughout the duration of the construction project, effective the date of signature of the required SWPPP. These conditions apply to all operators on the project site. The project is subject to EPA’s NPDES General Permit through the CGP. The goal of this permit is to prevent the discharge of pollutants associated with construction activity from entering the existing and proposed storm drain system or surface waters. All contractors/operators involved in clearing, grading and excavation construction activities must sign the appropriate certification statement required, which will remain with the SWPPP. The owner must also sign a certification, which is to remain with the SWPPP in accordance with the signatory requirements of the SWPPP. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Once the SWPPP is finalized, a signed copy, plus supporting documents, must be held at the project site during construction. A copy must remain available to EPA, State and Local agencies, and other interested parties during normal business hours. The following items associated with this SWPPP must be posted in a prominent place at the construction site until final stabilization has been achieved: · The completed/submitted NOI form · Location where the public can view the SWPPP during normal business hours · A copy of the signed/submitted NOI, permit number issued by the EPA and a copy of the current CGP. Project specific SWPPP documents are not submitted to the US EPA unless the agency specifically requests a copy for review. SWPPP documents requested by a permitting authority, the permitee(s) will submit it in a timely manner. EPA inspectors will be allowed free and unrestricted access to the project site and all related documentation and records kept under the conditions of the permit. The permitee is expected to keep all BMP’s and Stormwater controls operating correctly and maintained regularly. Any additions to the project which will significantly change the anticipated discharges of pollutants, must be reported to the EPA. The EPA should also be notified in advance of any anticipated events of noncompliance. The permitee must also orally inform the EPA of any discharge, which may endanger health or the environment within 24 hours, with a written report following within 5 days. In maintaining the SWPPP, all records and supporting documents will be compiled together in an orderly fashion. Inspection reports and amendments to the SWPPP must remain with the document. Federal regulations require permitee(s) to keep their Project Specific SWPPP and all reports and documents for at least three (3) years after the project is complete. 3.2 Existing Site and Soil Conditions The total project area is approximately 3.92 acres and is located off Route 28. The project is bounded on the north by Mill Pond, on the east by a privately owned in and a wetland, on the west by Baxter Avenue, and bounded on the south by Gleason Avenue. The current site is comprised of four buildings, an inground swimming pool, a large, paved parking area, and areas of vegetation. The primary soil classification identified by the NRCS Web Soil Survey is Carver coarse sand (252A), which accounts for the entire property and project area. Based on the soil classification identified, runoff calculations have been performed using curve numbers corresponding to Hydrologic Soil Group (HSG) A. 3.3 Project Description and Intended Construction Sequence The site is currently comprised of four buildings, a paved parking area and lawn. The proposed activities will include the following major components: · The construction of one (1) 30’x30’ building overhand, one (1) concrete patio with an associated walkway, · The construction of a stormwater management system, and · Site grading The proposed project will disturb a total of approximately 27,944± S.F. (0.64± acres). Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Soil disturbing activities will include site demolition, installation of erosion and sedimentation controls, grading, storm drain inlets, stormwater management systems, and preparation for final landscaping. Please refer to Table 1 for the projects anticipated construction timetable. A description of BMP’s associated with project timetable and construction-phasing elements is provided in this Erosion and Sediment Control Plan. Table 1 – Anticipated Construction Timetable Construction Phasing Activity Anticipated Timetable Grubbing and Stripping of Limits of Construction Phase To be determined Rough Site Grading and Site Utilities To be determined Landscaping To be determined 3.4 Potential Sources of Pollution Any project site activities that have the potential to add pollutants to runoff are subject to the requirements of the SWPPP. Listed below are a description of potential sources of pollution from both sedimentation to Stormwater runoff, and pollutants from sources other than sedimentation. Table 2 – Potential Sources of Sediment to Stormwater Runoff Potential Source Activities/Comments Construction Site Entrance and Site Vehicles Vehicles leaving the site can track soils onto public roadways. Site Vehicles can readily transport exposed soils throughout the site and off-site areas. Grading Operations Exposed soils have the potential for erosion and discharge of sediment to off-site areas. Material Excavation, Relocation, and Stockpiling Stockpiling of materials during excavation and relocation of soils can contribute to erosion and sedimentation. In addition, fugitive dust from stockpiled material, vehicle transport and site grading can be deposited in wetlands and waterway. Landscaping Operations Landscaping operations specifically associated with exposed soils can contribute to erosion and sedimentation. Hydroseeding, if not properly applied, can runoff to adjacent wetlands and waterways. Table 3 – Potential Pollutants and Sources, other than Sediment to Stormwater Runoff Potential Source Activities/Comments Staging Areas and Construction Vehicles Vehicle refueling, minor equipment maintenance, sanitary facilities and hazardous waste storage Materials Storage Area General building materials, solvents, adhesives, paving materials, paints, aggregates, trash, etc. Construction Activities Construction, paving, curb/gutter installation, concrete pouring/mortar/stucco 3.5 Erosion and Sedimentation Control Best Management Practices All construction activities will implement Best Management Practices (BMP’s) in order to minimize overall site disturbance and impacts to the sites natural features. Please refer to the following sections for a detailed description of site specific BMP’s. In addition, an Erosion and Sedimentation Control Plan is provided in the Site Plans. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 3.6 Timetable and Construction Phasing This section provides the Owner and Contractor with a suggested order of construction that shall minimize erosion and the transport of sediments. The individual objectives of the construction techniques described herein shall be considered an integral component of the project design intent of each project phase. The construction sequence is not intended to prescribe definitive construction methods and should not be interpreted as a construction specification document. However, the Contractor shall follow the general construction phase principles provided below: · Protect and maintain existing vegetation wherever possible. · Minimize the area of disturbance. · To the extent possible, route unpolluted flows around disturbed areas. · Install mitigation devices as early as possible. · Minimize the time disturbed areas are left unstabilized. · Maintain siltation control devices in proper condition. · The contractor should use the suggested sequence and techniques as a general guide and modify the suggested methods and procedures as required to best suit seasonal, atmospheric, and site specific physical constraints for the purpose of minimizing the environmental impact of construction. Demolition, Grubbing and Stripping of Limits of Construction Phase · Install Temporary Erosion Control (TEC) devices as required to prevent sediment transport into resource areas. · Place a ring of silt socks and/or haybales around stockpiles. · Stabilize all exposed surfaces that will not be under immediate construction. · Store and/or dispose all pavement and building demolition debris as indicated in accordance with all applicable local, state, and federal regulations. Driveway Area Sub-Base Construction · Install temporary culverts and diversion ditches and additional TEC devices as required by individual construction area constraints to direct potential runoff toward detention areas designated for the current construction phase. · Compact gravel as work progresses to control erosion potential. · Apply water to control air suspension of dust. · Avoid creating an erosive condition due to over-watering. · Install piped utility systems as required as work progresses, keeping all inlets sealed until all downstream drainage system components are functional. Binder Construction · Fine grade gravel base and install processed gravel to the design grades. · Compact pavement base as work progresses. · Install pavement binder coat starting from the downhill end of the site and work toward the top. Finish Paving · Repair and stabilize damaged side slopes. · Clean inverts of drainage structures. · Install final top coat of pavement. Final Clean-up · Clean inverts of culverts and catch basins. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA · Remove sediment and debris from rip-rap outlet areas. · Remove TEC devices only after permanent vegetation and erosion control has been fully established. 3.7 Site Stabilization Grubbing Stripping and Grading · Erosion control devices shall be in place as shown on the design plans before grading commences. · Stripping shall be done in a manner, which will not concentrate runoff. If precipitation is expected, earthen berms shall be constructed around the area being stripped, with a silt sock, silt fence or haybale dike situated in an arc at the low point of the berm. · If intense precipitation is anticipated, silt socks, haybales, dikes and /or silt fences shall be used as required to prevent erosion and sediment transport. The materials required shall be stored on site at all time. · If water is required for soil compaction, it shall be added in a uniform manner that does not allow excess water to flow off the area being compacted. · Dust shall be held at a minimum by sprinkling exposed soil with an appropriate amount of water. Maintenance of Disturbed Surfaces · Runoff shall be diverted from disturbed side slopes in both cut and fill. · Mulching may be used for temporary stabilization. · Silt sock, haybale or silt fences shall be set where required to trap products of erosion and shall be maintained on a continuing basis during the construction process. Loaming and Seeding · Loam shall not be placed unless it is to be seeded directly thereafter. · All disturbed areas shall have a minimum of 4” of loam placed before seeded and mulched. · Consideration shall be given to hydro-mulching, especially on slopes in excess of 3 to 1. · Loamed and seeded slopes shall be protected from washout by mulching or other acceptable slope protection until vegetation begins to grow. Stormwater Collection System Installation · The Stormwater drainage system shall be installed from the downstream end up and in a manner which will not allow runoff from disturbed areas to enter pipes. · Excavation for the drainage system shall not be left open when rainfall is expected overnight. If left open under other circumstances, pipe ends shall be closed by a staked board or by an equivalent method. · All catch basin openings shall be covered by a silt bag between the grate and the frame or protected from sediment by silt fence surrounding the catch basin grate. · During the installation of the infiltration systems, ensure that loose material from the construction of the town home roof shingles is swept and removed from the area prior to connecting the roof drains to the infiltration systems. No roof drains shall be connected to the infiltration systems until all tributary roof areas have been thoroughly cleared of debris that could impact the infiltration system functions. Completion of Paved Areas · During the placement of sub-base and pavement, the entrance to the Stormwater drainage systems shall be sealed when rain is expected. When these entrances are closed, consideration must be Stormwater Report Tidewater Motor Lodge West Yarmouth, MA given to the direction of run-off and measures shall be undertaken to minimize erosion and to provide for the collection of sediment. · In some situations, it may be necessary to keep catch basins open. · Appropriate arrangements shall be made downstream to remove all sediment deposition. Stabilization of Surfaces · Stabilization of surfaces includes the placement of pavement, rip-rap, wood bark mulch and the establishment of vegetated surfaces. · Upon completion of construction, all surfaces shall be stabilized even though it is apparent that future construction efforts will cause their disturbance. · Vegetated cover shall be established during the proper growing season and shall be enhanced by soil adjustment for proper pH, nutrients and moisture content. · Surfaces that are disturbed by erosion processes or vandalism shall be stabilized as soon as possible. · Areas where construction activities have permanently or temporarily ceased shall be stabilized within 14 days from the last construction activity, except when construction activity will resume within 21 days (e.g., the total time period that construction activity is temporarily ceased is less than 21 days). · Hydro-mulching of grass surfaces is recommended, especially if seeding of the surfaces is required outside the normal growing season. · Hay mulch is an effective method of temporarily stabilizing surfaces, but only if it is properly secured by branches, weighted snow fences or weighted chicken wire. 3.8 Temporary Structural Erosion Control Measures Temporary erosion control measures serve to minimize construction-associated impacts to wetland resource and undisturbed areas. Please refer to the following sections for a description of temporary erosion control measures implemented as part of the project and this sample SWPPP. 3.8.1 Silt Socks, Haybales, and Silt Fencing The siltation barriers will demarcate the limit of work, form a work envelope and provide additional assurance that construction equipment will not enter the adjacent wetlands or undisturbed portions of the site. All barriers will remain in place until disturbed areas are stabilized. 3.8.2 Temporary Stormwater Diversion Swale A temporary diversion swale is an effective practice for temporarily diverting stormwater flows and to reduce stormwater runoff velocities during storm events. The swale channel can be installed before infrastructure construction begins at the site, or as needed throughout the construction process. The diversion swale should be routinely compacted or seeded to minimize the amount of exposed soil. 3.8.3 Dewatering Basins Dewatering may be required during stormwater system, foundation construction and utility installation. Should the need for dewatering arise, groundwater will be pumped directly into a temporary settling basin, which will act as a sediment trap during construction. All temporary settling basins will be located within close proximity of daily work activities. Prior to discharge, all groundwater will be treated by means of the settling basin or acceptable substitute. Discharges from sediment basins will be free of visible floating, suspended and settleable solids that would impair the functions of a wetland or degrade the chemical composition of the wetland resource area receiving ground or surface water flows and will be to the combined system. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 3.8.4 Material Stockpiling Locations Piping and trench excavate associated with the subsurface utility work will be contained with a single row of silt socks and/or haybales. 3.9 Permanent Structural Erosion Control Measures Permanent erosion control measures serve to minimize post-construction impacts to wetland resource areas and undisturbed areas. Please refer to the Site Plans and Long-Term Operations and Maintenance Plan for a description of permanent erosion control measures implemented as part of the project and this SWPPP. 3.10 Good Housekeeping Best Management Practices 3.10.1 Street Sweeping Dorothy Road in front of the project property shall be swept clean on a daily basis at the conclusion of the work day of any soils tracked onto it from the project site. All sweepings shall be disposed of off-site in accordance with all applicable laws and regulations. 3.10.2 Material Handling and Waste Management Solid waste generation during the construction period will be primarily construction debris. The debris will include scrap lumber (used forming and shoring pallets and other shipping containers), waste packaging materials (plastic sheeting and cardboard), scrap cable and wire, roll-off containers (or dumpsters) and will be removed by a contract hauler to a properly licensed landfill. The roll-off containers will be covered with a properly secured tarp before the hauler exits the site. In addition to construction debris, the construction work force will generate some amount of household-type wastes (food packing, soft drink containers, and other paper). Trash containers for these wastes will be located around the site and will be emptied regularly so as to prevent wind-blown litter. This waste will also be removed by a contract hauler. All hazardous waste material such as oil filters, petroleum products, paint and equipment maintenance fluids will be stored in structurally sound and sealed shipping containers in the hazardous-materials storage area and segregated from other non-waste materials. Secondary containment will be provided for all materials in the hazardous materials storage area and will consist of commercially available spill pallets. Additionally, all hazardous materials will be disposed of in accordance with federal, state and municipal regulations. Two temporary sanitary facilities (portable toilets) will be provided at the site in the combined staging area. The toilets will be away from a concentrated flow path and traffic flow and will have collection pans underneath as secondary treatment. All sanitary waste will be collected from an approved party at a minimum of three times per week. 3.10.3 Building Material Staging Areas Construction equipment and maintenance materials will be stored at the combined staging area and materials storage areas. Silt fence will be installed around the perimeter to designate the staging and materials storage area. A watertight shipping container will be used to store hand tools, small parts and other construction materials. Non-hazardous building materials such as packaging material (wood, plastic and glass) and construction scrap material (brick, wood, steel, metal scraps, and pine cuttings) will be stored in a separate covered storage facility adjacent to other stored materials. All hazardous-waste materials such as oil filters, petroleum products, paint and equipment maintenance fluids will be stored in structurally sound and sealed containers under cover within the hazardous materials storage area. Large items such as framing materials and stockpiled lumber will be stored in the open storage area. Such materials will be elevated on wood blocks to minimize contact with runoff. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA The combined storage areas are expected to remain clean, well-organized and equipped with ample cleaning supplies as appropriate for the materials being stored. Perimeter controls such as containment structures, covers and liners will be repaired or replaced as necessary to maintain proper function. 3.10.4 Designated Washout Areas Designated temporary, below-ground concrete washout areas will be constructed, as required, to minimize the pollution potential associated with concrete, paint, stucco, mixers etc. Signs will, if required, be posted marking the location of the washout area to ensure that concrete equipment operators use the proper facility. Concrete pours will not be conducted during or before an anticipated precipitation event. All excess concrete and concrete washout slurries from the concrete mixer trucks and chutes will be discharged to the washout area or hauled off-site for disposal. 3.10.5 Equipment/Vehicle Maintenance and Fueling Areas Several types of vehicles and equipment will 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 will be performed off-site. A small, 20-gallon pickup bed fuel tank will be kept on-site in the combined staging area. When vehicle fueling must occur on-site, the fueling activity will occur in the staging area. Only minor equipment maintenance will occur on-site. Vehicular refueling or maintenance shall not be allowed within the Adjacent Upland Resource Area (AURA) or in any protected wetland resource areas as defined by the Town of Arlington Regulations for Wetland Protection. All equipment fluids generated from maintenance activities will be disposed of into designated drums stored on spill pallets. Absorbent, spill-cleanup materials and spill kits will be available at the combined staging and materials storage area. Drip pans will be placed under all equipment receiving maintenance and vehicles and equipment parked overnight. 3.10.6 Equipment/Vehicle Wash down Area All equipment and vehicle washing will be performed off-site. 3.10.7 Spill Prevention Plan A spill containment kit will be kept on-site in the Contractor’s trailer and/or the designated staging area throughout the duration of construction. Should there be an accidental release of petroleum product into a resource area, the appropriate agencies will be immediately notified. 3.10.8 Inspections Maintenance of existing and proposed BMP’s to address stormwater management facilities during construction is an on-going process. The purpose of the inspections is to observe all sources of stormwater or non-stormwater discharge as identified in the SWPPP as well as the status of the receiving waters and fulfill the requirements of the Order of Conditions. The following sections describe the appropriate inspection measures to adequately implement the project’s SWPPP. A blank inspection form is provided at the end of this section. Completed inspection forms are to be maintained on site. Inspection Personnel The owner’s appointed representative will be responsible for performing regular inspections of erosion controls and ordering repairs as necessary. Inspection Frequency Inspections will be performed by qualified personnel once every 7 days, in accordance with the CGP. The inspections must be documented on the inspection form provided at the end of this section, and completed forms will be provided to the on-site supervisor and maintained at the Owner’s office throughout the entire duration of construction. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Inspection Reporting Each inspection report will summarize the scope of the inspection, name(s) and qualifications of personnel making the inspection, and major observations relating to the implementation of the SWPPP, including compliance and non-compliance items. Completed inspection reports will remain with the completed SWPPP on site. 3.10.9 Amendment Requirements The final SWPPP is intended to be a working document that is utilized regularly on the construction site, and provides guidance to the Contractor. It must reflect changes made to the originally proposed plan and will be updated to include project specific activities and ensure that they are in compliance with the NPDES General Permit and state and local laws and regulations. It should be amended whenever there is a change in design, construction, operation or maintenance that affects discharge of pollutants. The following items should be addressed should an amendment to the SWPPP occur: · Dates of certain construction activities such as major grading activities, clearing and initiation of and completion of stabilization measures should be recorded. · Future amendments to the SWPPP will be recorded as required. As this SWPPP is amended, all amendments will be kept on site and made part of the SWPPP. · Upon completion of site stabilization (completed as designed and/or 70% background vegetative cover), it can be documented and marked on the plans. Inspections are no longer required at this time. · Inspections often identify areas not included in the original SWPPP, which will require the SWPPP to be amended. These updates should be made within seven days of being recognized by the inspector. 3.11 SWPPP Inspection and Maintenance Report The following form is an example to be used for SWPPP Inspection Reporting. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Stormwater Construction Site Inspection and Maintenance Report TO BE COMPLETED AT LEAST EVERY 7 DAYS. AFTER SITE STABILIZATION, TO BE COMPLETED AT LEAST ONCE PER MONTH FOR THREE YEARS OR UNTIL A NOTICE OF TERMINATION IS FILED (IF APPLICABLE). General Information Project Name Tidewater Motor Lodge NPDES Tracking No. (if applicable) Location 135 Route 28 West Yarmouth, MA Date of Inspection Start/End Time Inspector’s Name(s) Inspector’s Title(s) Inspector’s Contact Information Inspector’s Qualifications Describe present phase of construction Type of Inspection:  Regular  Pre-storm event  During storm event  Post-storm event Weather Information Has there been a storm event since the last inspection? Yes No If yes, provide: Storm Start Date & Time: Storm Duration (hrs): Approximate Amount of Precipitation (in): Weather at time of this inspection?  Clear Cloudy  Rain  Sleet  Fog  Snowing  High Winds  Other: Temperature: Have any discharges occurred since the last inspection? Yes No If yes, describe: Are there any discharges at the time of inspection? Yes No If yes, describe: Site-specific BMPs · Number the structural and non-structural BMPs identified in your SWPPP on your site map and list them below (add as many BMPs as necessary). Carry a copy of the numbered site map with you during your inspections. This list will ensure that you are inspecting all required BMPs at your site. · Describe corrective actions initiated, date completed, and note the person that completed the work in the Corrective Action Log. BMP BMP Installed? BMP Maintenance Required? Corrective Action Needed and Notes Action required by whom and when 1 Catch Basin Protection Yes No Yes No 2 Haybale & Silt Fencing Yes No Yes No Stormwater Report Tidewater Motor Lodge West Yarmouth, MA BMP BMP Installed? BMP Maintenance Required? Corrective Action Needed and Notes Action required by whom and when 3 Straw Wattles Yes No Yes No 4 Construction Entrance Yes No Yes No 5 Sediment Basins Yes No Yes No 6 Dewatering Pit Yes No Yes No 7 Yes No Yes No Overall Site Issues Below are some general site issues that should be assessed during inspections. Customize this list as needed for conditions at your site. BMP/activity Implemented? Maintenance Required? Corrective Action Needed and Notes Action required by whom and when 1 Are all slopes and disturbed areas not actively being worked properly stabilized? Yes No Yes No 2 Are natural resource areas (e.g., streams, wetlands, mature trees, etc.) protected with barriers or similar BMPs? Yes No Yes No 3 Are perimeter controls and sediment barriers adequately installed (keyed into substrate) and maintained? Yes No Yes No Stormwater Report Tidewater Motor Lodge West Yarmouth, MA BMP/activity Implemented? Maintenance Required? Corrective Action Needed and Notes Action required by whom and when 4 Are discharge points and receiving waters free of any sediment deposits? Yes No Yes No 5 Are storm drain inlets properly protected? Yes No Yes No 6 Is the construction exit preventing sediment from being tracked into the street? Yes No Yes No 7 Is trash/litter from work areas collected and placed in covered dumpsters? Yes No Yes No 8 Are washout facilities (e.g., paint, stucco, concrete) available, clearly marked, and maintained? Yes No Yes No 9 Are vehicle and equipment fueling, cleaning, and maintenance areas free of spills, leaks, or any other deleterious material? Yes No Yes No Vehicle Maintenance not allowed on site 10 Are materials that are potential stormwater contaminants stored inside or under cover? Yes No Yes No 11 Are non-stormwater discharges (e.g., wash water, dewatering) properly controlled? Yes No Yes No 12 (Other) Yes No Yes No Non-Compliance Describe any incidents of non-compliance not described above: Stormwater Report Tidewater Motor Lodge West Yarmouth, MA CERTIFICATION STATEMENT “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.” Print name and title: . (Qualified Person Performing the Inspection) Signature:_____________________________________________________ Date: . Print name and title: __________________________________________________________________________ (Contractor/Operator) Signature:______________________________________________________ Date: Stormwater Report Tidewater Motor Lodge West Yarmouth, MA SECTION 4.0 LONG-TERM POLLUTION PREVENTION & OPERATION AND MAINTENANCE PLAN Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 4.0 LONG-TERM POLLUTION PREVENTION & OPERATION AND MAINTENANCE PLAN As required by Standard #4 of the Stormwater Management Policy, this Long-Term Pollution Prevention Plan has been developed for source control and pollution prevention at the site after construction. MAINTENANCE RESPONSIBILITY Ensuring that the provisions of the Long-Term Pollution Prevention Plan are followed will be the responsibility of The Applicant, Hari Hospitality, LLC. GOOD HOUSEKEEPING PRACTICES The site to be kept clean of trash and debris at all times. Trash, junk, etc. is not to be left outside. VEHICLE WASHING CONTROLS The following BMP’s, or equivalent measures, methods or practices are required if you are engaged in vehicle washing and/or steam cleaning: It is allowable to rinse down the body or a vehicle, including the bed of a truck, with just water without doing any wash water control BMP’s. If you wash (with mild detergents) on an area that infiltrates water, such as gravel, grass, or loose soil, it is acceptable to let the wash water infiltrate as long as you only wash the body of vehicles. However, if you wash on a paved area and use detergents or other cleansers, or if you wash/rinse the engine compartment or the underside of vehicles, you must take the vehicles to a commercial vehicle wash. REQUIREMENTS FOR ROUTINE INSPECTIONS AND MAINTENANCE OF STORMWATER BMPS All stormwater BMPs are to be inspected and maintain as follows; Haybales, Silt Fence, and other temporary measures The temporary erosion control measures will be installed up gradient of any wetland resource area where any disturbance or alteration might otherwise allow for erosion or sedimentation. They will be regularly inspected to ensure that they are functioning adequately. Additional supplies of these temporary measures will be stockpiled on site for any immediate needs or routine replacement. Water Quality Treatment Units The water quality treatment structures require periodic inspection and cleaning to maintain operation and function. Owners should have these units inspected on a semi-annual basis and after periods of intense precipitation. Inspections can be done by sing a clear Plexiglass tube (“sludge judge”) to extract a water column sample. When sediment accumulation reaches 15% of storage capacity, cleaning of the unit is required. These water quality structures must and will be checked and cleaned immediately after petroleum spills; contact appropriate regulatory agencies. Maintenance of these units should be done by a vacuum truck that will remove the water, sediment, debris, floating hydrocarbons and other materials in unit. Proper cleaning and disposal of the removed materials and liquid must be followed. Underground Infiltration Systems Maintenance is required for the proper operation of the underground infiltration system. Infiltration systems are prone to failure due to clogging if the upstream water quality units are not maintained. The use of pretreatment BMPs will minimize failure and maintenance requirements. After construction, the infiltration system shall be inspected after every major storm for the first few months to ensure proper stabilization and function. Water levels in the access ports shall be recorded over several days to check the Stormwater Report Tidewater Motor Lodge West Yarmouth, MA drainage of the systems. It is recommended that a log book be maintained showing the depth of water in the detention/infiltration systems at each observation in order to determine the rate at which the system dewaters after runoff producing storm events. Once the performance characteristics of the detention/infiltration have been verified, the monitoring schedule can be reduced to an annual basis, unless the performance data suggests that a more frequent schedule is required. Preventive maintenance on the infiltration system shall be performed at least twice a year, and sediment shall be removed from any and all pretreatment and collection structures. Sediment shall be removed when deposits approach within six inches of the invert heights of connecting pipes between unit rows, or in sumped inlet structures. Ponded water inside the systems (as visible from the access ports) that remains after several days most likely indicates that the bottom of the system is clogged and will require cleaning or replacement. The system is designed with a defined top portal area at the “down-flow” end of the chamber that can be cut out to accept up to a 10-inch diameter riser pipe. The 10-inch riser can be used as an observation well and as access for a vacuum truck tube for use in removing sediment. The “down flow” ends of the units have end walls that are closed on the bottom. The closed bottom functions like a coffer dam, with most of the sediment depositing prior to flowing into the next chamber, facilitating its removal through the riser pipe, which is positioned directly above this area. In addition to the routine maintenance described above, an operation and maintenance log. This log must be maintained for a minimum of three years after construction of the system, and include inspection reports and notes on any repairs, replacement, and disposal (including material and location). This log must be made available to MassDEP and the Conservation Commission upon request. In addition, members and agents of MassDEP shall be allowed to enter and inspect the property and drainage system to ensure compliance with this O&M plan. PROVISIONS FOR MAINTENANCE OF LAWNS, GARDENS AND OTHER LANDSCAPE AREAS Suggested Maintenance Operations A. Trees and Shrubs Disease and Pest Management - Prevention of disease or infestation is the first step of Pest Management. A plant that is in overall good health is far less susceptible to disease. Good general landscape maintenance can reduce problems from disease. Inspections of plant materials for signs of disease or infestation are to be performed monthly by the Landscape Maintenance Contractor’s Certified Arborist. This is a critical step for early diagnosis. Trees and Shrubs that have been diagnosed to have a plant disease or an infestation of insect pests are to be treated promptly with an appropriate material by a licensed applicator. Fertilization - Trees and shrubs live outside their natural environment and should be given proper care to maintain health and vigor. Fertilizing trees and shrubs provides the plants with nutrients needed to resist insect attack, to resist drought and to grow thicker foliage. Fertilizing of new and old trees may be done in one of three ways, in either the early spring or the late fall. · Systemic Injection of new and existing trees on trees 2 inches or greater in diameter. You must be licensed to apply this method. · Soil Injection – a liquid fertilizer with a product such as Arbor Green or Rapid Grow injected into the soil under the drip zone of a tree or shrub. Material must be used according to manufacturers’ specifications to be effective. Outside contracting is recommended. · Punch Bar Method – a dry fertilizer such as 10-10-10, may be used by punched holes in the drip zone of the tree 12-18” deep, two feet apart around the circumference, to the edge of the drip line. Three pounds of fertilizer should be used per diameter inch for trees with trunks six inches or more in diameter. · Fertilizer of shrubs – use a fertilizer such as 10-10-10, broadcast over the planting area according to the manufacturers’ rate and water in. · All fertilization must be noted on daily maintenance log. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Watering - Trees and Shrubs will need supplemental watering to remain in vigorous health. All new plants need to be watered once a week in cool weather, twice a week during warm weather, and up to three times in a week during periods of extreme heat and drought. Trees and shrubs should be watered in such a manner as to totally saturate the soil in the root zone area. Over-watering or constant saturation of the soil must be avoided as this could lead to root rot and other disease problems. The use of a soil moisture meter can help you monitor the soil’s water intake. Plant Replacement - Unhealthy plants that may cause widespread infestation of other nearby plants shall be immediately removed from the site. Any vegetation removed from the site must be recorded and submitted with the daily maintenance log. The area shall be treated to prevent further infestation. The plant shall then be replaced with a healthy specimen of the same species and size. This work shall have a pre-established budget allowance for the year. A spring inspection of all plant materials shall be performed to identify those plant materials that are not in vigorously healthy condition. Unhealthy plant materials shall be evaluated. If the problem is determined to be minor the plant material shall be given appropriate restorative care in accordance with this maintenance guideline until it is restored to a vigorously healthy condition. Unhealthy plant materials that do not respond to restorative care or are determined to be beyond saving shall be replaced with a healthy specimen of the same species and size. In the case of the necessity of replacing extremely large plant materials the Landscape Architect shall determine the size of the replacement plant. Pruning - Proper pruning is the selective removal of branches without changing the plant’s natural appearance, or habit of growth. All tree pruning is to be performed by a licensed Arborist. All branches that are dead, broken, scared or crossing should be removed. All cuts should be made at the collar and not cut flush with the base. Pruning on the site shall be done for the following purposes; · To maintain or reduce the size of a tree or shrub · To remove dead, diseased or damaged branches · To rejuvenate old shrubs and encourage new growth · To stimulate future flower and fruit development · To maximize the visibility of twig color · To prevent damage and reduce hazards to people and properties All shrubs are recommended to be pruned on an annual basis to prevent the shrub from becoming overgrown and eliminate the need for drastic pruning. There are several types of pruning for deciduous shrubs. Hand snips should be used to maintain a more natural look or hand shears can be used for a more formal appearance. Winter Protection - All trees and shrubs are to be watered, fertilized, and mulched before the first frost. All stakes should be checked and ties adjusted. Damaged branches should be pruned. Broadleaf and Coniferous Evergreen plant materials are to be sprayed with an anti-desiccant product to prevent winter burn. The application shall be repeated during a suitable mid-winter thaw. Shrubs located in areas likely to be piled with snow during snow removal (but not designated as Snow Storage Areas) shall be marked by six-foot high poles with bright green banner flags. Stockpiles of snow are not to be located in these areas due to potential damage to the plant materials from both the weight of the snow and the snow melting chemicals. At the fall landscape maintenance conference parameters will be discussed between the Landscape Maintenance Contractor and the snow removal contractor to assure minimal damage and loss of landscape amenities during the winter season. Seasonal Clean Up - A thorough spring cleanup is to be performed. This includes the removal and replacement of dead or unhealthy plant materials and the cleanup of plant debris and any general debris that has accumulated over the winter season. Mulch is to be lightly raked to clean debris from the surface without removing any mulch. Twigs and debris are to be removed from the planting beds throughout the growing season. Mulching - Planting beds shall be mulched with a treated shredded hardwood mulch free from dirt, debris, and insects. A sample of this mulch shall be given to the Owner for approval prior to installation. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Maintain a 2-3” maximum depth and keep free of weeds either by hand weeding or by the use of a pre-emergent weed control such as Treflan or Serfian. Seasonal re-mulching shall occur as necessary in the spring and the fall to maintain this minimum depth. When new mulch is added to the planting bed it shall be spread to create a total depth of no more than three inches. Edges should be maintained in a cleanly edged fashion. Mulch shall not be placed directly against the trunk of any tree or shrub. B. Groundcover and Perennials Disease and Pest Management – Pesticides and herbicides should be applied only as problems occur, with the proper chemical applied only by a trained professional or in the case of pesticide, a Certified Pesticide Applicator. Plants should be monitored weekly and treated accordingly. Fertilizer – The health of the plants can be maintained or improved, and their growth encouraged by an application of complete fertilizer. Apply a fertilizer such as 4-12-4 as growth becomes apparent and before mulching. Apply to all groundcover and perennial planting areas by hand and avoid letting the fertilizer come in contact with the foliage, or use a liquid fertilizer and apply by soaking the soil. Apply according to the manufacturers’ specifications. Fertilization shall stop at the end of July. Water – Groundcovers and Perennials will need supplemental watering in order to become established, healthy plants. All new plants need to be watered once a week in cool weather, twice a week during warm weather, and up to three times in a week during periods of extreme heat and drought. Until established, groundcovers and perennials should be watered in such a manner as to totally saturate the soil in the root zone area, to a depth of 6 inches. Once established, perennials shall continue to be watered as necessary to maintain them in a vigorous healthy condition. Over-watering or constant saturation of the soil must be avoided as this could lead to root rot and other disease problems. The use of a soil moisture meter can help you monitor the soil’s water intake. On-site water shall be furnished by the Owner. Hose and other watering equipment shall be furnished by the Landscape Maintenance Contractor. Replacement – Any unhealthy plant/s that may cause widespread infestation of other nearby plants shall be immediately removed from the site. Any vegetation removed from the site must be recorded and submitted with the landscape maintenance log. The area shall be treated to prevent further infestation. The plant/s shall then be replaced with healthy specimen/s of the same species and size. Old Forge shall have a pre-established budget allowance for this type of replacement, each year. Plant material that is damaged as a result of other landscape maintenance activities, such as mowing, shall be replaced with healthy specimens of the same species and size, at no additional cost to the owner. Deadheading – Perennials shall be checked on a weekly basis and dead-headed once flowers have faded or as necessary based on plant type and duration of flower. Spent flowers can be pinched off with the thumb and forefinger. Continue to remove all faded flowers until Fall. All associated debris shall be removed from site daily. Staking – Upright-growing perennials need support especially when in flower. Use of bamboo stakes, galvanized wire hoops or mesh may be necessary for their support. Supports should be put in place before they have become too difficult to handle. The supports should not be taller than the mature height of the perennial plant. Division of Perennials – Two or three-year-old perennials are easily divided in the spring if more plants are needed. To divide, cut out the entire section of plant to be divided, including roots. The larger divisions (those with three or more shoots), can be set out immediately in their permanent location, where they can be expected to bloom the same season. Smaller divisions are best planted in an out-of-the-way planting bed until the following autumn or spring, when they can be moved to their permanent location. Weeding – All planting beds should be kept weed-free. Weed either by hand or with a pre-emergent herbicide such as Treflen used according to manufacturers’ specifications. Manual weeding is to be used in combination with the use of spot applications of herbicides. Both live and dead weeds are to be pulled and removed from the site. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA All herbicide applications shall be documented in the Landscape Maintenance Log. The actual product label or the manufacturer’s product specification sheet for the specific product shall also be included in the Log. Only personnel with appropriate applicator licenses shall supervise and/or perform the application of pesticide products requiring a license. Winterizing – Perennial gardens should be cleaned-up when growth ceases in the fall. Remove foliage of plants that normally die down to the ground. Divide and replant over-grown clumps. C. Lawn Areas - Turf Systems Mowing – Proper mowing is an integral part of any good turf maintenance program. Without it, the finest in fertilization, watering and other vital maintenance practices would be completely ineffective. Proper mowing will help control dicot weeds; help the turf survive during periods of extreme heat, and gain strength and vigor to resist disease and other infestations. Mowing height – The proper mowing height will vary somewhat according to the type of grass. The most common type of seed & sod lawns contain a mixture of bluegrass, fine fescue and perennial rye, which should be mowed at 2-3 inches. Mowing frequency – The basic rule of thumb for mowing frequency is to never remove more than 1/3 of the grass blade in one mowing. Example: if you want to mow your turf at 2 inches, you should cut it when it reaches 3 inches. Removing more than ½ of the grass plant at a time can put the plant into shock, thus making it more susceptible to stress disease and weed infestation. Mowing frequency will vary with the growing season and should be set by the plant height and not a set date. It will often be necessary to mow twice a week during periods of surge growth to help maintain plant health and color. Mowing should be cut back during periods of stress. Grass clippings should be removed whenever they are thick enough to layer the turf. The return of clippings to the soil actually adds nutrients and helps retain moisture. Heavily clumped grass clippings are a sign of infrequent mowing, calling for an adjustment in the mowing schedule. When mowing any area, try to alternate mowing patterns. This tends to keep grass blades more erect and assures an even cut. A dull mower will cause color loss due to tearing of the turf plant, and since mowing will ultimately determine the appearance of any turf area there is an absolute necessity for a clean sharp cut. Weed & Pest Control and Fertilizing- In order to maintain turf grass health, vigor color, and nutrients, fertilizer must be added to the soil. Recommendations for fertilization of lawn areas are as follows; fertilize at the rate of one (1) pound of nitrogen per thousand square feet, per year is optimum. Fertilizer should be a balanced slow release, sulfur coated type fertilizer. Weed Control - All turf areas will require some weed control, for both weed grasses and dicot weeds. Weeds should be treated at the appropriate time and with a material labeled for the target weed. Please refer to the fertilizer weed and pest schedule for timing. Pest Control - All turf areas will require some pest control. Pests should be treated at the appropriate time with a material labeled for the target pest. Please refer to the fertilizer, weed and pest schedule for timing. Lime - A common cause for an unhealthy lawn is acidic soil. When the pH is below the neutral range (between 6-7) vital plant nutrients become fixed in the soil and cannot be absorbed by the grass plant. Lime corrects an acid soil condition, supplies calcium for plant growth and improves air and water circulation. Limestone applied at the rate of 50 lbs. per thousand square feet will adjust the soil pH one point over a period of 6-9 months. D. Fertilizer, Weed & Pest Control Schedule – Turf Systems Spring - Fertilize one (1) pound of nitrogen per 1,000 square feet (April) Pre-emergent weed grass control Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Broadleaf weed control Late Spring - Fertilize one (1) pound of nitrogen per 1,000 square feet (June) Pre-emergent weed grass control Broadleaf weed control Insect Control (if needed) *Summer - Fertilize one (1) pound of nitrogen per 1,000 square feet (August) Broadleaf weed control (if needed) Insect Control (if needed) Fall - Fertilize one (1) pound of nitrogen per 1,000 square feet (September) *Omit if area is not to be irrigated Lawn Maintenance Task Schedule MARCH (Weather permitting) · Clean up winter debris, sand, leaves, trash etc. · Re-edge mulch beds, maintain at 2-3” maximum. · Fertilize plants · Aerate and thatch turf (conditions permitting) APRIL · Reseed or sod all areas needing attention. · Fertilize and weed control · Lime · Start mowing when grass reaches 2-1/2”, mow to 2” MAY · Mow turf to 2-2-1/2” · Weed as necessary. · Check for disease and pest problems in both turf and plants. JUNE · Mow turf to 2-1/2” – 3” · Fertilize and weed control. · Weed · Check for disease and pest problems in both turf and plants, treat as necessary. PROVISIONS FOR SOLID WASTE MANAGEMENT (SITE TRASH) Trash will be placed in on-site dumpsters and the Owner will make provisions for its regular and timely removal. SNOW DISPOSAL AND PLOWING PLANS The purpose of the snow and snowmelt management plan is to provide guidelines regarding snow disposal site selection, site preparation and maintenance that are acceptable to the Department of Environmental Protection. For the areas that require snow removal, snow storage onsite will largely be accomplished by using pervious areas along the shoulder of the roadway and development as windrowed by plows. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA · Avoid dumping of snow into any water body, including rivers, ponds, or wetlands. In addition to water quality impacts and flooding, snow disposed of in open water can cause navigational hazards when it freezes into ice blocks. · Avoid disposing of snow on top of storm drain catch basins or in stormwater basins. Snow combined with sand and debris may block a storm drainage system, causing localized flooding. A high volume of sand, sediment, and litter released from melting snow also may be quickly transported through the system into surface water. · In significant storm events, the melting or off-site trucking of snow may be implemented. These activities shall be conducted in accordance with all local, state and federal regulations. · Snow shall be removed from the areas around on-site fire-hydrants to maintain emergency access to hydrants at all times. Removable flags or markers should be placed on hydrants to allow snow removal crews to more easily locate hydrants and not damage them with plows or other snow removal equipment. WINTER ROAD SALT AND/OR SAND USE AND STORAGE RESTRICTIONS The applicant will be responsible for sanding and salting the site. No storage on site. STREET SWEEPING SCHEDULES There are three types of sweepers: Mechanical, Regenerative Air, and Vacuum Filter. 1) Mechanical: Mechanical sweepers use brooms or rotary brushes to scour the pavement. 2) Regenerative Air: These sweepers blow air onto the road or parking lot surface, causing fines to rise where they are vacuumed. 3) Vacuum filter: These sweepers remove fines along roads. Two general types of vacuum filter sweepers are available - wet and dry. The dry type uses a broom in combination with the vacuum. The wet type uses water for dust suppression Regardless of the type chosen, the efficiency of street sweeping is increased when sweepers are operated in tandem. This project has not included street sweeping as part of the TSS removal calculations. However, it is recommended that street sweeping of the parking areas occur four times a year, including once after the spring snow melt. Reuse and Disposal of Street Sweepings Once removed from paved surfaces, the sweepings must be handled and disposed of properly. Mass DEP’s Bureau of Waste Prevention has issued a written policy regarding the reuse and disposal of street sweepings. These sweepings are regulated as a solid waste, and can be used in three ways: · In one of the ways already approved by Mass DEP (e.g., daily cover in a landfill, additive to compost, fill in a public way) · If approved under a Beneficial Use Determination · Disposed in a landfill TRAINING OF STAFF OR PERSONNEL INVOLVED WITH IMPLEMENTING LONG-TERM POLLUTION PREVENTION PLAN The Long-Term Pollution Prevention Plan is to be implemented by property owner of the site. Trained and, if required, licensed Professionals are to be hired by the owner as applicable to implement the Long-Term Pollution Prevention Plan. LIST OF EMERGENCY CONTACTS FOR IMPLEMENTING LONG-TERM POLLUTION PREVENTION PLAN The applicant will be required to implement the Long-Term Pollution Prevention Plan and will create and maintain a list of emergency contacts. Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Stormwater Report Tidewater Motor Lodge West Yarmouth, MA POST CONSTRUCTION PHASE INSPECTION SCHEDULE AND EVALUATION CHECKLIST Inspection Date Inspector BMP Inspected Inspection Frequency Requirement s Comments Recommendation Follow-up Inspection Required (yes/no) Water Quality Unit Four times a year Infiltration System Twice a year 1. Refer to the Massachusetts Stormwater Handbook Volume Two: Stormwater Technical Handbook (February 2008) for recommendations regarding frequency for inspections and maintenance of specific BMP’s 2. Inspections to be conducted by a qualified professional such as an environmental scientist or civil engineer. 3. Limited or no use of sodium chloride salts, fertilizers or pesticides recommended. 4. Other Notes: (Include deviations from Conservation Commission Approvals, Planning Board Approvals and Approved Plans) Stormwater Report Tidewater Motor Lodge West Yarmouth, MA SECTION 5.0 HYDROLOGY CALCULATIONS Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 5.01 EXISTING WATERSHED PLAN PUBLIC -- V A R I A B L E W I D T H MAIN ST R E E T - R O U T E 2 8 G G OHW OHW OHW OHW OHW OHW OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OHW OHW OHW OHW O H W O H W 33 ' W I D E B A X T E R A V E N U E 40' WIDE GLEASON A V E N U E OH W OH W OH W OH W OH W 349 Main Street - Route 28 West Yarmouth, Massachusetts 02673 508 778 8919 IN TIDEWATER MOTOR LODGE 135 ROUTE 28 WEST YARMOUTH MASSACHUSETTS (BARNSTABLE COUNTY) NOVEMBER 7, 2024 EXISTING CONDITIONS WATERSHED MAP V-1.0 ISSUED FOR PERMITTING NOT FOR CONSTRUCTION Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 5.02 EXISTING HYDROLOGY CALCULATIONS (HYDROCAD™ PRINTOUTS) DP1 To CBs DP2 Off-Site (North) DP3 Off-Site (Wetland) Routing Diagram for 5071100-EWAM Prepared by BSC Group, Printed 10/3/2024 HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link EWAM 5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 2HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-year Type III 24-hr Default 24.00 1 3.38 2 2 10-year Type III 24-hr Default 24.00 1 4.93 2 3 25-year Type III 24-hr Default 24.00 1 5.89 2 4 50-Year Type III 24-hr Default 24.00 1 6.62 2 5 100-year Type III 24-hr Default 24.00 1 7.38 2 EWAM 5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 3HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (sq-ft) CN Description (subcatchment-numbers) 73,272 39 >75% Grass cover, Good, HSG A (DP1, DP2, DP3) 72,365 98 Paved parking, HSG A (DP1, DP2, DP3) 24,601 98 Roofs, HSG A (DP1, DP2, DP3) 1,248 98 Water Surface, HSG A (DP2) 171,486 73 TOTAL AREA EWAM 5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 4HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (sq-ft) Soil Group Subcatchment Numbers 171,486 HSG A DP1, DP2, DP3 0 HSG B 0 HSG C 0 HSG D 0 Other 171,486 TOTAL AREA EWAM 5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 5HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (sq-ft) HSG-B (sq-ft) HSG-C (sq-ft) HSG-D (sq-ft) Other (sq-ft) Total (sq-ft) Ground Cover 73,272 0 0 0 0 73,272 >75% Grass cover, Good 72,365 0 0 0 0 72,365 Paved parking 24,601 0 0 0 0 24,601 Roofs 1,248 0 0 0 0 1,248 Water Surface 171,486 0 0 0 0 171,486 TOTAL AREA EWAM Type III 24-hr 2-year Rainfall=3.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 6HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.17% Impervious Runoff Depth=1.34"Subcatchment DP1: To CBs Tc=6.0 min CN=77 Runoff=3.38 cfs 10,676 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=2.62"Subcatchment DP2: Off-Site (North) Tc=6.0 min CN=93 Runoff=2.16 cfs 6,916 cf Runoff Area=44,331 sf 17.39% Impervious Runoff Depth=0.14"Subcatchment DP3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.03 cfs 532 cf Total Runoff Area = 171,486 sf Runoff Volume = 18,124 cf Average Runoff Depth = 1.27" 42.73% Pervious = 73,272 sf 57.27% Impervious = 98,214 sf EWAM Type III 24-hr 2-year Rainfall=3.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 7HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP1: To CBs Runoff = 3.38 cfs @ 12.09 hrs, Volume= 10,676 cf, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 46,685 98 Paved parking, HSG A 14,573 98 Roofs, HSG A 34,209 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,209 35.83% Pervious Area 61,258 64.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 3 2 1 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=95,467 sf Runoff Volume=10,676 cf Runoff Depth=1.34" Tc=6.0 min CN=77 3.38 cfs EWAM Type III 24-hr 2-year Rainfall=3.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 8HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP2: Off-Site (North) Runoff = 2.16 cfs @ 12.09 hrs, Volume= 6,916 cf, Depth= 2.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 2 1 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=31,688 sf Runoff Volume=6,916 cf Runoff Depth=2.62" Tc=6.0 min CN=93 2.16 cfs EWAM Type III 24-hr 2-year Rainfall=3.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 9HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP3: Off-Site (Wetland) Runoff = 0.03 cfs @ 12.46 hrs, Volume= 532 cf, Depth= 0.14" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 5,461 98 Roofs, HSG A 2,246 98 Paved parking, HSG A 36,624 39 >75% Grass cover, Good, HSG A 44,331 49 Weighted Average 36,624 82.61% Pervious Area 7,707 17.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.034 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=44,331 sf Runoff Volume=532 cf Runoff Depth=0.14" Tc=6.0 min CN=49 0.03 cfs EWAM Type III 24-hr 10-year Rainfall=4.93"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 10HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.17% Impervious Runoff Depth=2.56"Subcatchment DP1: To CBs Tc=6.0 min CN=77 Runoff=6.59 cfs 20,402 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=4.13"Subcatchment DP2: Off-Site (North) Tc=6.0 min CN=93 Runoff=3.31 cfs 10,904 cf Runoff Area=44,331 sf 17.39% Impervious Runoff Depth=0.61"Subcatchment DP3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.41 cfs 2,261 cf Total Runoff Area = 171,486 sf Runoff Volume = 33,567 cf Average Runoff Depth = 2.35" 42.73% Pervious = 73,272 sf 57.27% Impervious = 98,214 sf EWAM Type III 24-hr 10-year Rainfall=4.93"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 11HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP1: To CBs Runoff = 6.59 cfs @ 12.09 hrs, Volume= 20,402 cf, Depth= 2.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 46,685 98 Paved parking, HSG A 14,573 98 Roofs, HSG A 34,209 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,209 35.83% Pervious Area 61,258 64.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=95,467 sf Runoff Volume=20,402 cf Runoff Depth=2.56" Tc=6.0 min CN=77 6.59 cfs EWAM Type III 24-hr 10-year Rainfall=4.93"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 12HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP2: Off-Site (North) Runoff = 3.31 cfs @ 12.08 hrs, Volume= 10,904 cf, Depth= 4.13" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 3 2 1 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=31,688 sf Runoff Volume=10,904 cf Runoff Depth=4.13" Tc=6.0 min CN=93 3.31 cfs EWAM Type III 24-hr 10-year Rainfall=4.93"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 13HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP3: Off-Site (Wetland) Runoff = 0.41 cfs @ 12.13 hrs, Volume= 2,261 cf, Depth= 0.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 5,461 98 Roofs, HSG A 2,246 98 Paved parking, HSG A 36,624 39 >75% Grass cover, Good, HSG A 44,331 49 Weighted Average 36,624 82.61% Pervious Area 7,707 17.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=44,331 sf Runoff Volume=2,261 cf Runoff Depth=0.61" Tc=6.0 min CN=49 0.41 cfs EWAM Type III 24-hr 25-year Rainfall=5.89"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 14HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.17% Impervious Runoff Depth=3.38"Subcatchment DP1: To CBs Tc=6.0 min CN=77 Runoff=8.70 cfs 26,915 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=5.07"Subcatchment DP2: Off-Site (North) Tc=6.0 min CN=93 Runoff=4.02 cfs 13,399 cf Runoff Area=44,331 sf 17.39% Impervious Runoff Depth=1.02"Subcatchment DP3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.91 cfs 3,769 cf Total Runoff Area = 171,486 sf Runoff Volume = 44,083 cf Average Runoff Depth = 3.08" 42.73% Pervious = 73,272 sf 57.27% Impervious = 98,214 sf EWAM Type III 24-hr 25-year Rainfall=5.89"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 15HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP1: To CBs Runoff = 8.70 cfs @ 12.09 hrs, Volume= 26,915 cf, Depth= 3.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 46,685 98 Paved parking, HSG A 14,573 98 Roofs, HSG A 34,209 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,209 35.83% Pervious Area 61,258 64.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=95,467 sf Runoff Volume=26,915 cf Runoff Depth=3.38" Tc=6.0 min CN=77 8.70 cfs EWAM Type III 24-hr 25-year Rainfall=5.89"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 16HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP2: Off-Site (North) Runoff = 4.02 cfs @ 12.08 hrs, Volume= 13,399 cf, Depth= 5.07" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=31,688 sf Runoff Volume=13,399 cf Runoff Depth=5.07" Tc=6.0 min CN=93 4.02 cfs EWAM Type III 24-hr 25-year Rainfall=5.89"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 17HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP3: Off-Site (Wetland) Runoff = 0.91 cfs @ 12.11 hrs, Volume= 3,769 cf, Depth= 1.02" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 5,461 98 Roofs, HSG A 2,246 98 Paved parking, HSG A 36,624 39 >75% Grass cover, Good, HSG A 44,331 49 Weighted Average 36,624 82.61% Pervious Area 7,707 17.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 1 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=44,331 sf Runoff Volume=3,769 cf Runoff Depth=1.02" Tc=6.0 min CN=49 0.91 cfs EWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 18HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.17% Impervious Runoff Depth=4.03"Subcatchment DP1: To CBs Tc=6.0 min CN=77 Runoff=10.33 cfs 32,028 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=5.80"Subcatchment DP2: Off-Site (North) Tc=6.0 min CN=93 Runoff=4.56 cfs 15,303 cf Runoff Area=44,331 sf 17.39% Impervious Runoff Depth=1.38"Subcatchment DP3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=1.35 cfs 5,091 cf Total Runoff Area = 171,486 sf Runoff Volume = 52,422 cf Average Runoff Depth = 3.67" 42.73% Pervious = 73,272 sf 57.27% Impervious = 98,214 sf EWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 19HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP1: To CBs Runoff = 10.33 cfs @ 12.09 hrs, Volume= 32,028 cf, Depth= 4.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 46,685 98 Paved parking, HSG A 14,573 98 Roofs, HSG A 34,209 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,209 35.83% Pervious Area 61,258 64.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=95,467 sf Runoff Volume=32,028 cf Runoff Depth=4.03" Tc=6.0 min CN=77 10.33 cfs EWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 20HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP2: Off-Site (North) Runoff = 4.56 cfs @ 12.08 hrs, Volume= 15,303 cf, Depth= 5.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 5 4 3 2 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=31,688 sf Runoff Volume=15,303 cf Runoff Depth=5.80" Tc=6.0 min CN=93 4.56 cfs EWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 21HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP3: Off-Site (Wetland) Runoff = 1.35 cfs @ 12.11 hrs, Volume= 5,091 cf, Depth= 1.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 5,461 98 Roofs, HSG A 2,246 98 Paved parking, HSG A 36,624 39 >75% Grass cover, Good, HSG A 44,331 49 Weighted Average 36,624 82.61% Pervious Area 7,707 17.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=44,331 sf Runoff Volume=5,091 cf Runoff Depth=1.38" Tc=6.0 min CN=49 1.35 cfs EWAM Type III 24-hr 100-year Rainfall=7.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 22HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.17% Impervious Runoff Depth=4.71"Subcatchment DP1: To CBs Tc=6.0 min CN=77 Runoff=12.04 cfs 37,462 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=6.55"Subcatchment DP2: Off-Site (North) Tc=6.0 min CN=93 Runoff=5.12 cfs 17,290 cf Runoff Area=44,331 sf 17.39% Impervious Runoff Depth=1.79"Subcatchment DP3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=1.87 cfs 6,603 cf Total Runoff Area = 171,486 sf Runoff Volume = 61,355 cf Average Runoff Depth = 4.29" 42.73% Pervious = 73,272 sf 57.27% Impervious = 98,214 sf EWAM Type III 24-hr 100-year Rainfall=7.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 23HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP1: To CBs Runoff = 12.04 cfs @ 12.09 hrs, Volume= 37,462 cf, Depth= 4.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 46,685 98 Paved parking, HSG A 14,573 98 Roofs, HSG A 34,209 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,209 35.83% Pervious Area 61,258 64.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=95,467 sf Runoff Volume=37,462 cf Runoff Depth=4.71" Tc=6.0 min CN=77 12.04 cfs EWAM Type III 24-hr 100-year Rainfall=7.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 24HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP2: Off-Site (North) Runoff = 5.12 cfs @ 12.08 hrs, Volume= 17,290 cf, Depth= 6.55" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=31,688 sf Runoff Volume=17,290 cf Runoff Depth=6.55" Tc=6.0 min CN=93 5.12 cfs EWAM Type III 24-hr 100-year Rainfall=7.38"5071100-EWAM Printed 10/3/2024Prepared by BSC Group Page 25HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment DP3: Off-Site (Wetland) Runoff = 1.87 cfs @ 12.10 hrs, Volume= 6,603 cf, Depth= 1.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 5,461 98 Roofs, HSG A 2,246 98 Paved parking, HSG A 36,624 39 >75% Grass cover, Good, HSG A 44,331 49 Weighted Average 36,624 82.61% Pervious Area 7,707 17.39% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment DP3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 2 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=44,331 sf Runoff Volume=6,603 cf Runoff Depth=1.79" Tc=6.0 min CN=49 1.87 cfs Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 5.03 PROPOSED WATERSHED PLAN PUBLIC -- V A R I A B L E W I D T H MAIN ST R E E T - R O U T E 2 8 G G OHW OHW OHW OHW OHW OHW OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OH W OHW OHW OHW OHW O H W O H W 33 ' W I D E B A X T E R A V E N U E 40' WIDE GLEASON A V E N U E OH W OH W OH W OH W OH W S S S S S S S S SSSS S S S S S S S S S SSS S S S S S S S S S S S S S S S S S S SS S S S S S S S S S S S S S S S S RD RD RD 349 Main Street - Route 28 West Yarmouth, Massachusetts 02673 508 778 8919 IN TIDEWATER MOTOR LODGE 135 ROUTE 28 WEST YARMOUTH MASSACHUSETTS (BARNSTABLE COUNTY) NOVEMBER 7, 2024 PROPOSED CONDITIONS WATERSHED MAP 1 OF 1 ISSUED FOR PERMITTING NOT FOR CONSTRUCTION Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 5.04 PROPOSED HYDROLOGY CALCULATIONS (HYDROCAD™ PRINTOUTS) PR1 To CBs PR2 Off-Site (North) PR3 Off-Site (Wetland) PR4 Patio PR4a Roof 1P R-Tank Routing Diagram for 5071100-PWAM Prepared by BSC Group, Printed 10/3/2024 HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Subcat Reach Pond Link PWAM 5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 2HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Rainfall Events Listing Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-year Type III 24-hr Default 24.00 1 3.38 2 2 10-year Type III 24-hr Default 24.00 1 4.93 2 3 25-year Type III 24-hr Default 24.00 1 5.89 2 4 50-Year Type III 24-hr Default 24.00 1 6.62 2 5 100-year Type III 24-hr Default 24.00 1 7.38 2 PWAM 5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 3HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (sq-ft) CN Description (subcatchment-numbers) 71,403 39 >75% Grass cover, Good, HSG A (PR1, PR2, PR3) 72,755 98 Paved parking, HSG A (PR1, PR2, PR3) 24,384 98 Roofs, HSG A (PR1, PR2, PR3, PR4a) 1,696 98 Unconnected pavement, HSG A (PR4) 1,248 98 Water Surface, HSG A (PR2) 171,486 73 TOTAL AREA PWAM 5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 4HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (sq-ft) Soil Group Subcatchment Numbers 171,486 HSG A PR1, PR2, PR3, PR4, PR4a 0 HSG B 0 HSG C 0 HSG D 0 Other 171,486 TOTAL AREA PWAM 5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 5HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (sq-ft) HSG-B (sq-ft) HSG-C (sq-ft) HSG-D (sq-ft) Other (sq-ft) Total (sq-ft) Ground Cover 71,403 0 0 0 0 71,403 >75% Grass cover, Good 72,755 0 0 0 0 72,755 Paved parking 24,384 0 0 0 0 24,384 Roofs 1,696 0 0 0 0 1,696 Unconnected pavement 1,248 0 0 0 0 1,248 Water Surface 171,486 0 0 0 0 171,486 TOTAL AREA PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 6HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.16% Impervious Runoff Depth=1.34"Subcatchment PR1: To CBs Tc=6.0 min CN=77 Runoff=3.38 cfs 10,676 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=2.62"Subcatchment PR2: Off-Site (North) Tc=6.0 min CN=93 Runoff=2.16 cfs 6,916 cf Runoff Area=41,735 sf 16.74% Impervious Runoff Depth=0.14"Subcatchment PR3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.03 cfs 501 cf Runoff Area=1,696 sf 100.00% Impervious Runoff Depth=3.15"Subcatchment PR4: Patio Tc=6.0 min CN=98 Runoff=0.13 cfs 445 cf Runoff Area=900 sf 100.00% Impervious Runoff Depth=3.15"Subcatchment PR4a: Roof Tc=6.0 min CN=98 Runoff=0.07 cfs 236 cf Peak Elev=8.03' Storage=136 cf Inflow=0.20 cfs 681 cfPond 1P: R-Tank Outflow=0.05 cfs 681 cf Total Runoff Area = 171,486 sf Runoff Volume = 18,774 cf Average Runoff Depth = 1.31" 41.64% Pervious = 71,403 sf 58.36% Impervious = 100,083 sf PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 7HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: To CBs Runoff = 3.38 cfs @ 12.09 hrs, Volume= 10,676 cf, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 46,897 98 Paved parking, HSG A 14,356 98 Roofs, HSG A 34,214 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,214 35.84% Pervious Area 61,253 64.16% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 3 2 1 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=95,467 sf Runoff Volume=10,676 cf Runoff Depth=1.34" Tc=6.0 min CN=77 3.38 cfs PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 8HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Off-Site (North) Runoff = 2.16 cfs @ 12.09 hrs, Volume= 6,916 cf, Depth= 2.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 2 1 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=31,688 sf Runoff Volume=6,916 cf Runoff Depth=2.62" Tc=6.0 min CN=93 2.16 cfs PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 9HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR3: Off-Site (Wetland) Runoff = 0.03 cfs @ 12.46 hrs, Volume= 501 cf, Depth= 0.14" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 4,561 98 Roofs, HSG A 2,424 98 Paved parking, HSG A 34,750 39 >75% Grass cover, Good, HSG A 41,735 49 Weighted Average 34,750 83.26% Pervious Area 6,985 16.74% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.032 0.03 0.028 0.026 0.024 0.022 0.02 0.018 0.016 0.014 0.012 0.01 0.008 0.006 0.004 0.002 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=41,735 sf Runoff Volume=501 cf Runoff Depth=0.14" Tc=6.0 min CN=49 0.03 cfs PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 10HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4: Patio Runoff = 0.13 cfs @ 12.08 hrs, Volume= 445 cf, Depth= 3.15" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 1,696 98 Unconnected pavement, HSG A 1,696 100.00% Impervious Area 1,696 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4: Patio Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=1,696 sf Runoff Volume=445 cf Runoff Depth=3.15" Tc=6.0 min CN=98 0.13 cfs PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 11HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4a: Roof Runoff = 0.07 cfs @ 12.08 hrs, Volume= 236 cf, Depth= 3.15" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 2-year Rainfall=3.38" Area (sf) CN Description 900 98 Roofs, HSG A 900 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4a: Roof Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 2-year Rainfall=3.38" Runoff Area=900 sf Runoff Volume=236 cf Runoff Depth=3.15" Tc=6.0 min CN=98 0.07 cfs PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 12HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: R-Tank Inflow Area = 2,596 sf,100.00% Impervious, Inflow Depth = 3.15" for 2-year event Inflow = 0.20 cfs @ 12.08 hrs, Volume= 681 cf Outflow = 0.05 cfs @ 11.75 hrs, Volume= 681 cf, Atten= 76%, Lag= 0.0 min Discarded = 0.05 cfs @ 11.75 hrs, Volume= 681 cf Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 8.03' @ 12.46 hrs Surf.Area= 245 sf Storage= 136 cf Plug-Flow detention time= 14.0 min calculated for 681 cf (100% of inflow) Center-of-Mass det. time= 14.0 min ( 769.3 - 755.3 ) Volume Invert Avail.Storage Storage Description #1A 7.11' 217 cf 15.48'W x 15.81'L x 4.03'H Field A 987 cf Overall - 445 cf Embedded = 542 cf x 40.0% Voids #2A 7.36' 400 cf Ferguson R-Tank XD 20 x 42 Inside #1 Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 42 Chambers in 7 Rows 617 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 7.11'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.05 cfs @ 11.75 hrs HW=7.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 13HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank - Chamber Wizard Field A Chamber Model = Ferguson R-Tank XD 20 (Ferguson R-Tank XD) Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 6 Chambers/Row x 1.97' Long = 11.81' Row Length +24.0" End Stone x 2 = 15.81' Base Length 7 Rows x 19.7" Wide + 24.0" Side Stone x 2 = 15.48' Base Width 3.0" Stone Base + 39.4" Chamber Height + 6.0" Stone Cover = 4.03' Field Height 42 Chambers x 9.5 cf = 400.5 cf Chamber Storage 42 Chambers x 10.6 cf = 445.0 cf Displacement 986.8 cf Field - 445.0 cf Chambers = 541.8 cf Stone x 40.0% Voids = 216.7 cf Stone Storage Chamber Storage + Stone Storage = 617.2 cf = 0.014 af Overall Storage Efficiency = 62.5% Overall System Size = 15.81' x 15.48' x 4.03' 42 Chambers 36.5 cy Field 20.1 cy Stone PWAM Type III 24-hr 2-year Rainfall=3.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 14HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank Inflow Discarded Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=2,596 sf Peak Elev=8.03' Storage=136 cf 0.20 cfs 0.05 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 15HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.16% Impervious Runoff Depth=2.56"Subcatchment PR1: To CBs Tc=6.0 min CN=77 Runoff=6.59 cfs 20,402 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=4.13"Subcatchment PR2: Off-Site (North) Tc=6.0 min CN=93 Runoff=3.31 cfs 10,904 cf Runoff Area=41,735 sf 16.74% Impervious Runoff Depth=0.61"Subcatchment PR3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.38 cfs 2,129 cf Runoff Area=1,696 sf 100.00% Impervious Runoff Depth=4.69"Subcatchment PR4: Patio Tc=6.0 min CN=98 Runoff=0.19 cfs 663 cf Runoff Area=900 sf 100.00% Impervious Runoff Depth=4.69"Subcatchment PR4a: Roof Tc=6.0 min CN=98 Runoff=0.10 cfs 352 cf Peak Elev=8.80' Storage=263 cf Inflow=0.29 cfs 1,015 cfPond 1P: R-Tank Outflow=0.05 cfs 1,015 cf Total Runoff Area = 171,486 sf Runoff Volume = 34,450 cf Average Runoff Depth = 2.41" 41.64% Pervious = 71,403 sf 58.36% Impervious = 100,083 sf PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 16HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: To CBs Runoff = 6.59 cfs @ 12.09 hrs, Volume= 20,402 cf, Depth= 2.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 46,897 98 Paved parking, HSG A 14,356 98 Roofs, HSG A 34,214 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,214 35.84% Pervious Area 61,253 64.16% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 7 6 5 4 3 2 1 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=95,467 sf Runoff Volume=20,402 cf Runoff Depth=2.56" Tc=6.0 min CN=77 6.59 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 17HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Off-Site (North) Runoff = 3.31 cfs @ 12.08 hrs, Volume= 10,904 cf, Depth= 4.13" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 3 2 1 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=31,688 sf Runoff Volume=10,904 cf Runoff Depth=4.13" Tc=6.0 min CN=93 3.31 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 18HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR3: Off-Site (Wetland) Runoff = 0.38 cfs @ 12.13 hrs, Volume= 2,129 cf, Depth= 0.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 4,561 98 Roofs, HSG A 2,424 98 Paved parking, HSG A 34,750 39 >75% Grass cover, Good, HSG A 41,735 49 Weighted Average 34,750 83.26% Pervious Area 6,985 16.74% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=41,735 sf Runoff Volume=2,129 cf Runoff Depth=0.61" Tc=6.0 min CN=49 0.38 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 19HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4: Patio Runoff = 0.19 cfs @ 12.08 hrs, Volume= 663 cf, Depth= 4.69" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 1,696 98 Unconnected pavement, HSG A 1,696 100.00% Impervious Area 1,696 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4: Patio Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=1,696 sf Runoff Volume=663 cf Runoff Depth=4.69" Tc=6.0 min CN=98 0.19 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 20HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4a: Roof Runoff = 0.10 cfs @ 12.08 hrs, Volume= 352 cf, Depth= 4.69" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 10-year Rainfall=4.93" Area (sf) CN Description 900 98 Roofs, HSG A 900 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4a: Roof Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 10-year Rainfall=4.93" Runoff Area=900 sf Runoff Volume=352 cf Runoff Depth=4.69" Tc=6.0 min CN=98 0.10 cfs PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 21HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: R-Tank Inflow Area = 2,596 sf,100.00% Impervious, Inflow Depth = 4.69" for 10-year event Inflow = 0.29 cfs @ 12.08 hrs, Volume= 1,015 cf Outflow = 0.05 cfs @ 11.66 hrs, Volume= 1,015 cf, Atten= 84%, Lag= 0.0 min Discarded = 0.05 cfs @ 11.66 hrs, Volume= 1,015 cf Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 8.80' @ 12.55 hrs Surf.Area= 245 sf Storage= 263 cf Plug-Flow detention time= 30.3 min calculated for 1,015 cf (100% of inflow) Center-of-Mass det. time= 30.3 min ( 778.6 - 748.3 ) Volume Invert Avail.Storage Storage Description #1A 7.11' 217 cf 15.48'W x 15.81'L x 4.03'H Field A 987 cf Overall - 445 cf Embedded = 542 cf x 40.0% Voids #2A 7.36' 400 cf Ferguson R-Tank XD 20 x 42 Inside #1 Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 42 Chambers in 7 Rows 617 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 7.11'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.05 cfs @ 11.66 hrs HW=7.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 22HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank - Chamber Wizard Field A Chamber Model = Ferguson R-Tank XD 20 (Ferguson R-Tank XD) Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 6 Chambers/Row x 1.97' Long = 11.81' Row Length +24.0" End Stone x 2 = 15.81' Base Length 7 Rows x 19.7" Wide + 24.0" Side Stone x 2 = 15.48' Base Width 3.0" Stone Base + 39.4" Chamber Height + 6.0" Stone Cover = 4.03' Field Height 42 Chambers x 9.5 cf = 400.5 cf Chamber Storage 42 Chambers x 10.6 cf = 445.0 cf Displacement 986.8 cf Field - 445.0 cf Chambers = 541.8 cf Stone x 40.0% Voids = 216.7 cf Stone Storage Chamber Storage + Stone Storage = 617.2 cf = 0.014 af Overall Storage Efficiency = 62.5% Overall System Size = 15.81' x 15.48' x 4.03' 42 Chambers 36.5 cy Field 20.1 cy Stone PWAM Type III 24-hr 10-year Rainfall=4.93"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 23HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank Inflow Discarded Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=2,596 sf Peak Elev=8.80' Storage=263 cf 0.29 cfs 0.05 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 24HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.16% Impervious Runoff Depth=3.38"Subcatchment PR1: To CBs Tc=6.0 min CN=77 Runoff=8.70 cfs 26,915 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=5.07"Subcatchment PR2: Off-Site (North) Tc=6.0 min CN=93 Runoff=4.02 cfs 13,399 cf Runoff Area=41,735 sf 16.74% Impervious Runoff Depth=1.02"Subcatchment PR3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=0.85 cfs 3,548 cf Runoff Area=1,696 sf 100.00% Impervious Runoff Depth=5.65"Subcatchment PR4: Patio Tc=6.0 min CN=98 Runoff=0.22 cfs 799 cf Runoff Area=900 sf 100.00% Impervious Runoff Depth=5.65"Subcatchment PR4a: Roof Tc=6.0 min CN=98 Runoff=0.12 cfs 424 cf Peak Elev=9.30' Storage=346 cf Inflow=0.34 cfs 1,223 cfPond 1P: R-Tank Outflow=0.05 cfs 1,223 cf Total Runoff Area = 171,486 sf Runoff Volume = 45,085 cf Average Runoff Depth = 3.15" 41.64% Pervious = 71,403 sf 58.36% Impervious = 100,083 sf PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 25HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: To CBs Runoff = 8.70 cfs @ 12.09 hrs, Volume= 26,915 cf, Depth= 3.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 46,897 98 Paved parking, HSG A 14,356 98 Roofs, HSG A 34,214 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,214 35.84% Pervious Area 61,253 64.16% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=95,467 sf Runoff Volume=26,915 cf Runoff Depth=3.38" Tc=6.0 min CN=77 8.70 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 26HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Off-Site (North) Runoff = 4.02 cfs @ 12.08 hrs, Volume= 13,399 cf, Depth= 5.07" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 4 3 2 1 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=31,688 sf Runoff Volume=13,399 cf Runoff Depth=5.07" Tc=6.0 min CN=93 4.02 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 27HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR3: Off-Site (Wetland) Runoff = 0.85 cfs @ 12.11 hrs, Volume= 3,548 cf, Depth= 1.02" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 4,561 98 Roofs, HSG A 2,424 98 Paved parking, HSG A 34,750 39 >75% Grass cover, Good, HSG A 41,735 49 Weighted Average 34,750 83.26% Pervious Area 6,985 16.74% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=41,735 sf Runoff Volume=3,548 cf Runoff Depth=1.02" Tc=6.0 min CN=49 0.85 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 28HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4: Patio Runoff = 0.22 cfs @ 12.08 hrs, Volume= 799 cf, Depth= 5.65" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 1,696 98 Unconnected pavement, HSG A 1,696 100.00% Impervious Area 1,696 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4: Patio Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=1,696 sf Runoff Volume=799 cf Runoff Depth=5.65" Tc=6.0 min CN=98 0.22 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 29HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4a: Roof Runoff = 0.12 cfs @ 12.08 hrs, Volume= 424 cf, Depth= 5.65" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 25-year Rainfall=5.89" Area (sf) CN Description 900 98 Roofs, HSG A 900 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4a: Roof Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 25-year Rainfall=5.89" Runoff Area=900 sf Runoff Volume=424 cf Runoff Depth=5.65" Tc=6.0 min CN=98 0.12 cfs PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 30HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: R-Tank Inflow Area = 2,596 sf,100.00% Impervious, Inflow Depth = 5.65" for 25-year event Inflow = 0.34 cfs @ 12.08 hrs, Volume= 1,223 cf Outflow = 0.05 cfs @ 11.62 hrs, Volume= 1,223 cf, Atten= 86%, Lag= 0.0 min Discarded = 0.05 cfs @ 11.62 hrs, Volume= 1,223 cf Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 9.30' @ 12.59 hrs Surf.Area= 245 sf Storage= 346 cf Plug-Flow detention time= 42.6 min calculated for 1,222 cf (100% of inflow) Center-of-Mass det. time= 42.6 min ( 788.0 - 745.4 ) Volume Invert Avail.Storage Storage Description #1A 7.11' 217 cf 15.48'W x 15.81'L x 4.03'H Field A 987 cf Overall - 445 cf Embedded = 542 cf x 40.0% Voids #2A 7.36' 400 cf Ferguson R-Tank XD 20 x 42 Inside #1 Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 42 Chambers in 7 Rows 617 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 7.11'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.05 cfs @ 11.62 hrs HW=7.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 31HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank - Chamber Wizard Field A Chamber Model = Ferguson R-Tank XD 20 (Ferguson R-Tank XD) Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 6 Chambers/Row x 1.97' Long = 11.81' Row Length +24.0" End Stone x 2 = 15.81' Base Length 7 Rows x 19.7" Wide + 24.0" Side Stone x 2 = 15.48' Base Width 3.0" Stone Base + 39.4" Chamber Height + 6.0" Stone Cover = 4.03' Field Height 42 Chambers x 9.5 cf = 400.5 cf Chamber Storage 42 Chambers x 10.6 cf = 445.0 cf Displacement 986.8 cf Field - 445.0 cf Chambers = 541.8 cf Stone x 40.0% Voids = 216.7 cf Stone Storage Chamber Storage + Stone Storage = 617.2 cf = 0.014 af Overall Storage Efficiency = 62.5% Overall System Size = 15.81' x 15.48' x 4.03' 42 Chambers 36.5 cy Field 20.1 cy Stone PWAM Type III 24-hr 25-year Rainfall=5.89"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 32HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank Inflow Discarded Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=2,596 sf Peak Elev=9.30' Storage=346 cf 0.34 cfs 0.05 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 33HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.16% Impervious Runoff Depth=4.03"Subcatchment PR1: To CBs Tc=6.0 min CN=77 Runoff=10.33 cfs 32,028 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=5.80"Subcatchment PR2: Off-Site (North) Tc=6.0 min CN=93 Runoff=4.56 cfs 15,303 cf Runoff Area=41,735 sf 16.74% Impervious Runoff Depth=1.38"Subcatchment PR3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=1.27 cfs 4,793 cf Runoff Area=1,696 sf 100.00% Impervious Runoff Depth=6.38"Subcatchment PR4: Patio Tc=6.0 min CN=98 Runoff=0.25 cfs 902 cf Runoff Area=900 sf 100.00% Impervious Runoff Depth=6.38"Subcatchment PR4a: Roof Tc=6.0 min CN=98 Runoff=0.13 cfs 479 cf Peak Elev=9.69' Storage=411 cf Inflow=0.39 cfs 1,380 cfPond 1P: R-Tank Outflow=0.05 cfs 1,380 cf Total Runoff Area = 171,486 sf Runoff Volume = 53,505 cf Average Runoff Depth = 3.74" 41.64% Pervious = 71,403 sf 58.36% Impervious = 100,083 sf PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 34HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: To CBs Runoff = 10.33 cfs @ 12.09 hrs, Volume= 32,028 cf, Depth= 4.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 46,897 98 Paved parking, HSG A 14,356 98 Roofs, HSG A 34,214 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,214 35.84% Pervious Area 61,253 64.16% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=95,467 sf Runoff Volume=32,028 cf Runoff Depth=4.03" Tc=6.0 min CN=77 10.33 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 35HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Off-Site (North) Runoff = 4.56 cfs @ 12.08 hrs, Volume= 15,303 cf, Depth= 5.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 5 4 3 2 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=31,688 sf Runoff Volume=15,303 cf Runoff Depth=5.80" Tc=6.0 min CN=93 4.56 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 36HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR3: Off-Site (Wetland) Runoff = 1.27 cfs @ 12.11 hrs, Volume= 4,793 cf, Depth= 1.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 4,561 98 Roofs, HSG A 2,424 98 Paved parking, HSG A 34,750 39 >75% Grass cover, Good, HSG A 41,735 49 Weighted Average 34,750 83.26% Pervious Area 6,985 16.74% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 1 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=41,735 sf Runoff Volume=4,793 cf Runoff Depth=1.38" Tc=6.0 min CN=49 1.27 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 37HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4: Patio Runoff = 0.25 cfs @ 12.08 hrs, Volume= 902 cf, Depth= 6.38" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 1,696 98 Unconnected pavement, HSG A 1,696 100.00% Impervious Area 1,696 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4: Patio Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=1,696 sf Runoff Volume=902 cf Runoff Depth=6.38" Tc=6.0 min CN=98 0.25 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 38HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4a: Roof Runoff = 0.13 cfs @ 12.08 hrs, Volume= 479 cf, Depth= 6.38" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 50-Year Rainfall=6.62" Area (sf) CN Description 900 98 Roofs, HSG A 900 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4a: Roof Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 50-Year Rainfall=6.62" Runoff Area=900 sf Runoff Volume=479 cf Runoff Depth=6.38" Tc=6.0 min CN=98 0.13 cfs PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 39HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: R-Tank Inflow Area = 2,596 sf,100.00% Impervious, Inflow Depth = 6.38" for 50-Year event Inflow = 0.39 cfs @ 12.08 hrs, Volume= 1,380 cf Outflow = 0.05 cfs @ 11.58 hrs, Volume= 1,380 cf, Atten= 88%, Lag= 0.0 min Discarded = 0.05 cfs @ 11.58 hrs, Volume= 1,380 cf Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 9.69' @ 12.64 hrs Surf.Area= 245 sf Storage= 411 cf Plug-Flow detention time= 52.8 min calculated for 1,380 cf (100% of inflow) Center-of-Mass det. time= 52.8 min ( 796.5 - 743.7 ) Volume Invert Avail.Storage Storage Description #1A 7.11' 217 cf 15.48'W x 15.81'L x 4.03'H Field A 987 cf Overall - 445 cf Embedded = 542 cf x 40.0% Voids #2A 7.36' 400 cf Ferguson R-Tank XD 20 x 42 Inside #1 Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 42 Chambers in 7 Rows 617 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 7.11'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.05 cfs @ 11.58 hrs HW=7.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 40HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank - Chamber Wizard Field A Chamber Model = Ferguson R-Tank XD 20 (Ferguson R-Tank XD) Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 6 Chambers/Row x 1.97' Long = 11.81' Row Length +24.0" End Stone x 2 = 15.81' Base Length 7 Rows x 19.7" Wide + 24.0" Side Stone x 2 = 15.48' Base Width 3.0" Stone Base + 39.4" Chamber Height + 6.0" Stone Cover = 4.03' Field Height 42 Chambers x 9.5 cf = 400.5 cf Chamber Storage 42 Chambers x 10.6 cf = 445.0 cf Displacement 986.8 cf Field - 445.0 cf Chambers = 541.8 cf Stone x 40.0% Voids = 216.7 cf Stone Storage Chamber Storage + Stone Storage = 617.2 cf = 0.014 af Overall Storage Efficiency = 62.5% Overall System Size = 15.81' x 15.48' x 4.03' 42 Chambers 36.5 cy Field 20.1 cy Stone PWAM Type III 24-hr 50-Year Rainfall=6.62"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 41HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank Inflow Discarded Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=2,596 sf Peak Elev=9.69' Storage=411 cf 0.39 cfs 0.05 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 42HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Time span=0.00-36.00 hrs, dt=0.01 hrs, 3601 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=95,467 sf 64.16% Impervious Runoff Depth=4.71"Subcatchment PR1: To CBs Tc=6.0 min CN=77 Runoff=12.04 cfs 37,462 cf Runoff Area=31,688 sf 92.30% Impervious Runoff Depth=6.55"Subcatchment PR2: Off-Site (North) Tc=6.0 min CN=93 Runoff=5.12 cfs 17,290 cf Runoff Area=41,735 sf 16.74% Impervious Runoff Depth=1.79"Subcatchment PR3: Off-Site (Wetland) Tc=6.0 min CN=49 Runoff=1.76 cfs 6,216 cf Runoff Area=1,696 sf 100.00% Impervious Runoff Depth=7.14"Subcatchment PR4: Patio Tc=6.0 min CN=98 Runoff=0.28 cfs 1,009 cf Runoff Area=900 sf 100.00% Impervious Runoff Depth=7.14"Subcatchment PR4a: Roof Tc=6.0 min CN=98 Runoff=0.15 cfs 536 cf Peak Elev=10.11' Storage=481 cf Inflow=0.43 cfs 1,545 cfPond 1P: R-Tank Outflow=0.05 cfs 1,545 cf Total Runoff Area = 171,486 sf Runoff Volume = 62,513 cf Average Runoff Depth = 4.37" 41.64% Pervious = 71,403 sf 58.36% Impervious = 100,083 sf PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 43HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: To CBs Runoff = 12.04 cfs @ 12.09 hrs, Volume= 37,462 cf, Depth= 4.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 46,897 98 Paved parking, HSG A 14,356 98 Roofs, HSG A 34,214 39 >75% Grass cover, Good, HSG A 95,467 77 Weighted Average 34,214 35.84% Pervious Area 61,253 64.16% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR1: To CBs Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=95,467 sf Runoff Volume=37,462 cf Runoff Depth=4.71" Tc=6.0 min CN=77 12.04 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 44HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Off-Site (North) Runoff = 5.12 cfs @ 12.08 hrs, Volume= 17,290 cf, Depth= 6.55" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 1,248 98 Water Surface, HSG A 4,567 98 Roofs, HSG A 23,434 98 Paved parking, HSG A 2,439 39 >75% Grass cover, Good, HSG A 31,688 93 Weighted Average 2,439 7.70% Pervious Area 29,249 92.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR2: Off-Site (North) Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 5 4 3 2 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=31,688 sf Runoff Volume=17,290 cf Runoff Depth=6.55" Tc=6.0 min CN=93 5.12 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 45HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR3: Off-Site (Wetland) Runoff = 1.76 cfs @ 12.10 hrs, Volume= 6,216 cf, Depth= 1.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 4,561 98 Roofs, HSG A 2,424 98 Paved parking, HSG A 34,750 39 >75% Grass cover, Good, HSG A 41,735 49 Weighted Average 34,750 83.26% Pervious Area 6,985 16.74% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR3: Off-Site (Wetland) Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 1 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=41,735 sf Runoff Volume=6,216 cf Runoff Depth=1.79" Tc=6.0 min CN=49 1.76 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 46HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4: Patio Runoff = 0.28 cfs @ 12.08 hrs, Volume= 1,009 cf, Depth= 7.14" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 1,696 98 Unconnected pavement, HSG A 1,696 100.00% Impervious Area 1,696 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4: Patio Runoff Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=1,696 sf Runoff Volume=1,009 cf Runoff Depth=7.14" Tc=6.0 min CN=98 0.28 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 47HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Subcatchment PR4a: Roof Runoff = 0.15 cfs @ 12.08 hrs, Volume= 536 cf, Depth= 7.14" Routed to Pond 1P : R-Tank Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Type III 24-hr 100-year Rainfall=7.38" Area (sf) CN Description 900 98 Roofs, HSG A 900 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PR4a: Roof Runoff Hydrograph Time (hours) 3635343332313029282726252423222120191817161514131211109876543210 Flo w ( c f s ) 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 100-year Rainfall=7.38" Runoff Area=900 sf Runoff Volume=536 cf Runoff Depth=7.14" Tc=6.0 min CN=98 0.15 cfs PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 48HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Summary for Pond 1P: R-Tank Inflow Area = 2,596 sf,100.00% Impervious, Inflow Depth = 7.14" for 100-year event Inflow = 0.43 cfs @ 12.08 hrs, Volume= 1,545 cf Outflow = 0.05 cfs @ 11.49 hrs, Volume= 1,545 cf, Atten= 89%, Lag= 0.0 min Discarded = 0.05 cfs @ 11.49 hrs, Volume= 1,545 cf Routing by Stor-Ind method, Time Span= 0.00-36.00 hrs, dt= 0.01 hrs Peak Elev= 10.11' @ 12.74 hrs Surf.Area= 245 sf Storage= 481 cf Plug-Flow detention time= 64.3 min calculated for 1,545 cf (100% of inflow) Center-of-Mass det. time= 64.3 min ( 806.5 - 742.2 ) Volume Invert Avail.Storage Storage Description #1A 7.11' 217 cf 15.48'W x 15.81'L x 4.03'H Field A 987 cf Overall - 445 cf Embedded = 542 cf x 40.0% Voids #2A 7.36' 400 cf Ferguson R-Tank XD 20 x 42 Inside #1 Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 42 Chambers in 7 Rows 617 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 7.11'8.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.05 cfs @ 11.49 hrs HW=7.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.05 cfs) PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 49HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank - Chamber Wizard Field A Chamber Model = Ferguson R-Tank XD 20 (Ferguson R-Tank XD) Inside= 19.7"W x 39.4"H => 4.84 sf x 1.97'L = 9.5 cf Outside= 19.7"W x 39.4"H => 5.38 sf x 1.97'L = 10.6 cf 6 Chambers/Row x 1.97' Long = 11.81' Row Length +24.0" End Stone x 2 = 15.81' Base Length 7 Rows x 19.7" Wide + 24.0" Side Stone x 2 = 15.48' Base Width 3.0" Stone Base + 39.4" Chamber Height + 6.0" Stone Cover = 4.03' Field Height 42 Chambers x 9.5 cf = 400.5 cf Chamber Storage 42 Chambers x 10.6 cf = 445.0 cf Displacement 986.8 cf Field - 445.0 cf Chambers = 541.8 cf Stone x 40.0% Voids = 216.7 cf Stone Storage Chamber Storage + Stone Storage = 617.2 cf = 0.014 af Overall Storage Efficiency = 62.5% Overall System Size = 15.81' x 15.48' x 4.03' 42 Chambers 36.5 cy Field 20.1 cy Stone PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/3/2024Prepared by BSC Group Page 50HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Pond 1P: R-Tank Inflow Discarded Hydrograph Time (hours)3635343332313029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=2,596 sf Peak Elev=10.11' Storage=481 cf 0.43 cfs 0.05 cfs Stormwater Report Tidewater Motor Lodge West Yarmouth, MA SECTION 6.0 ADDITIONAL DRAINAGE CALCULATIONS Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.01 TSS REMOVAL CALCULATIONS Stormwater Report Tidewater Motor Lodge West Yarmouth, MA PRIOR TO ENTERING INFILTRATION SYSTEM TSS Removal Calculation Worksheet Location: Tidewater Motor Lodge Project: 50711.00 Prepared By: M. Morrison Date: 10/07/2024 AREA 1 - New Impervious Total Impervious Area, Acres= 0.039 A B C D E BMP TSS Removal Rate Starting TSS Load* Amount Removed (BxC) Remaining Load (C-D) Water Quality Unit 0.77 1.00 0.77 0.23 TSS Removal = 0.77 Weighted Annual Average TSS Removal Rate [TSS Removal-1 (Area-1) + TSS Revoval-2 (Area-2)+ ….] / [Area-1 + Area-2 + ...] = 0.77 Project Site TSS Removal =0.77 Prj\2290800\Design\Drainage\2024-10-07 Pretreatment - Weighted Average TSS Calculation.xls 10/7/2024 12:24 PM Stormwater Report Tidewater Motor Lodge West Yarmouth, MA TOTAL REMOVAL TSS Removal Calculation Worksheet Location: Tidewater Motor Lodge Project: 50711.00 Prepared By: M. Morrison Date: 10/07/2024 AREA 1 - New Impervious (Concrete Patio) Total Impervious Area, Acres= 0.039 A B C D E BMP TSS Removal Rate Starting TSS Load* Amount Removed (BxC) Remaining Load (C-D) Water Quality Unit 0.77 1 0.77 0.23 R-Tank XD 0.8 0.23 0.18 0.05 TSS Removal = 0.95 Weighted Annual Average TSS Removal Rate [TSS Removal-1 (Area-1) + TSS Revoval-2 (Area-2)+ ….] / [Area-1 + Area-2 + ...] = 0.95 Project Site TSS Removal =0.95 Prj\2290800\Design\Drainage\2024-10-07 Weighted Average TSS Calculation.xls 10/7/2024 12:23 PM Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.02 GROUNDWATER RECHARGE VOLUME CALCULATIONS Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Required Recharge Volume Rv = F x Impervious Area Where: Rv = Recharge Volume F=Target Depth Factor associated with each Hydrologic Soil Group (F=0.25-inch for Soil Type C) Impervious Area = Proposed Pavement and Rooftop area on-site = 0.60 12 2,596 = Rv = 130 cf (required recharge volume) Storage Provided o Underground Infiltration System = 617 cubic feet provided. Refer to the HydroCAD storage table provided for more information. PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/7/2024Prepared by BSC Group Page 1HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: R-Tank Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 7.11 245 0 7.12 245 1 7.13 245 2 7.14 245 3 7.15 245 4 7.16 245 5 7.17 245 6 7.18 245 7 7.19 245 8 7.20 245 9 7.21 245 10 7.22 245 11 7.23 245 12 7.24 245 13 7.25 245 14 7.26 245 15 7.27 245 16 7.28 245 17 7.29 245 18 7.30 245 19 7.31 245 20 7.32 245 21 7.33 245 22 7.34 245 23 7.35 245 24 7.36 245 24 7.37 245 26 7.38 245 28 7.39 245 29 7.40 245 31 7.41 245 33 7.42 245 34 7.43 245 36 7.44 245 38 7.45 245 39 7.46 245 41 7.47 245 43 7.48 245 44 7.49 245 46 7.50 245 48 7.51 245 49 7.52 245 51 7.53 245 53 7.54 245 54 7.55 245 56 7.56 245 58 7.57 245 59 7.58 245 61 7.59 245 63 7.60 245 64 7.61 245 66 7.62 245 68 7.63 245 69 7.64 245 71 7.65 245 73 7.66 245 74 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 7.67 245 76 7.68 245 78 7.69 245 79 7.70 245 81 7.71 245 82 7.72 245 84 7.73 245 86 7.74 245 87 7.75 245 89 7.76 245 91 7.77 245 92 7.78 245 94 7.79 245 96 7.80 245 97 7.81 245 99 7.82 245 101 7.83 245 102 7.84 245 104 7.85 245 106 7.86 245 107 7.87 245 109 7.88 245 111 7.89 245 112 7.90 245 114 7.91 245 116 7.92 245 117 7.93 245 119 7.94 245 121 7.95 245 122 7.96 245 124 7.97 245 126 7.98 245 127 7.99 245 129 8.00 245 131 8.01 245 132 8.02 245 134 8.03 245 136 8.04 245 137 8.05 245 139 8.06 245 140 8.07 245 142 8.08 245 144 8.09 245 145 8.10 245 147 8.11 245 149 8.12 245 150 8.13 245 152 8.14 245 154 8.15 245 155 8.16 245 157 8.17 245 159 8.18 245 160 8.19 245 162 8.20 245 164 8.21 245 165 8.22 245 167 PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/7/2024Prepared by BSC Group Page 2HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: R-Tank (continued) Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8.23 245 169 8.24 245 170 8.25 245 172 8.26 245 174 8.27 245 175 8.28 245 177 8.29 245 179 8.30 245 180 8.31 245 182 8.32 245 184 8.33 245 185 8.34 245 187 8.35 245 189 8.36 245 190 8.37 245 192 8.38 245 194 8.39 245 195 8.40 245 197 8.41 245 198 8.42 245 200 8.43 245 202 8.44 245 203 8.45 245 205 8.46 245 207 8.47 245 208 8.48 245 210 8.49 245 212 8.50 245 213 8.51 245 215 8.52 245 217 8.53 245 218 8.54 245 220 8.55 245 222 8.56 245 223 8.57 245 225 8.58 245 227 8.59 245 228 8.60 245 230 8.61 245 232 8.62 245 233 8.63 245 235 8.64 245 237 8.65 245 238 8.66 245 240 8.67 245 242 8.68 245 243 8.69 245 245 8.70 245 247 8.71 245 248 8.72 245 250 8.73 245 252 8.74 245 253 8.75 245 255 8.76 245 257 8.77 245 258 8.78 245 260 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 8.79 245 261 8.80 245 263 8.81 245 265 8.82 245 266 8.83 245 268 8.84 245 270 8.85 245 271 8.86 245 273 8.87 245 275 8.88 245 276 8.89 245 278 8.90 245 280 8.91 245 281 8.92 245 283 8.93 245 285 8.94 245 286 8.95 245 288 8.96 245 290 8.97 245 291 8.98 245 293 8.99 245 295 9.00 245 296 9.01 245 298 9.02 245 300 9.03 245 301 9.04 245 303 9.05 245 305 9.06 245 306 9.07 245 308 9.08 245 310 9.09 245 311 9.10 245 313 9.11 245 315 9.12 245 316 9.13 245 318 9.14 245 319 9.15 245 321 9.16 245 323 9.17 245 324 9.18 245 326 9.19 245 328 9.20 245 329 9.21 245 331 9.22 245 333 9.23 245 334 9.24 245 336 9.25 245 338 9.26 245 339 9.27 245 341 9.28 245 343 9.29 245 344 9.30 245 346 9.31 245 348 9.32 245 349 9.33 245 351 9.34 245 353 PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/7/2024Prepared by BSC Group Page 3HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: R-Tank (continued) Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 9.35 245 354 9.36 245 356 9.37 245 358 9.38 245 359 9.39 245 361 9.40 245 363 9.41 245 364 9.42 245 366 9.43 245 368 9.44 245 369 9.45 245 371 9.46 245 373 9.47 245 374 9.48 245 376 9.49 245 377 9.50 245 379 9.51 245 381 9.52 245 382 9.53 245 384 9.54 245 386 9.55 245 387 9.56 245 389 9.57 245 391 9.58 245 392 9.59 245 394 9.60 245 396 9.61 245 397 9.62 245 399 9.63 245 401 9.64 245 402 9.65 245 404 9.66 245 406 9.67 245 407 9.68 245 409 9.69 245 411 9.70 245 412 9.71 245 414 9.72 245 416 9.73 245 417 9.74 245 419 9.75 245 421 9.76 245 422 9.77 245 424 9.78 245 426 9.79 245 427 9.80 245 429 9.81 245 431 9.82 245 432 9.83 245 434 9.84 245 435 9.85 245 437 9.86 245 439 9.87 245 440 9.88 245 442 9.89 245 444 9.90 245 445 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 9.91 245 447 9.92 245 449 9.93 245 450 9.94 245 452 9.95 245 454 9.96 245 455 9.97 245 457 9.98 245 459 9.99 245 460 10.00 245 462 10.01 245 464 10.02 245 465 10.03 245 467 10.04 245 469 10.05 245 470 10.06 245 472 10.07 245 474 10.08 245 475 10.09 245 477 10.10 245 479 10.11 245 480 10.12 245 482 10.13 245 484 10.14 245 485 10.15 245 487 10.16 245 489 10.17 245 490 10.18 245 492 10.19 245 494 10.20 245 495 10.21 245 497 10.22 245 498 10.23 245 500 10.24 245 502 10.25 245 503 10.26 245 505 10.27 245 507 10.28 245 508 10.29 245 510 10.30 245 512 10.31 245 513 10.32 245 515 10.33 245 517 10.34 245 518 10.35 245 520 10.36 245 522 10.37 245 523 10.38 245 525 10.39 245 527 10.40 245 528 10.41 245 530 10.42 245 532 10.43 245 533 10.44 245 535 10.45 245 537 10.46 245 538 PWAM Type III 24-hr 100-year Rainfall=7.38"5071100-PWAM Printed 10/7/2024Prepared by BSC Group Page 4HydroCAD® 10.20-5b s/n 00904 © 2023 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: R-Tank (continued) Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 10.47 245 540 10.48 245 542 10.49 245 543 10.50 245 545 10.51 245 547 10.52 245 548 10.53 245 550 10.54 245 552 10.55 245 553 10.56 245 555 10.57 245 556 10.58 245 558 10.59 245 560 10.60 245 561 10.61 245 563 10.62 245 565 10.63 245 566 10.64 245 568 10.65 245 569 10.66 245 570 10.67 245 571 10.68 245 572 10.69 245 573 10.70 245 574 10.71 245 575 10.72 245 576 10.73 245 577 10.74 245 578 10.75 245 579 10.76 245 580 10.77 245 581 10.78 245 582 10.79 245 583 10.80 245 584 10.81 245 585 10.82 245 586 10.83 245 587 10.84 245 588 10.85 245 589 10.86 245 590 10.87 245 591 10.88 245 592 10.89 245 593 10.90 245 594 10.91 245 595 10.92 245 596 10.93 245 597 10.94 245 598 10.95 245 598 10.96 245 599 10.97 245 600 10.98 245 601 10.99 245 602 11.00 245 603 11.01 245 604 11.02 245 605 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 11.03 245 606 11.04 245 607 11.05 245 608 11.06 245 609 11.07 245 610 11.08 245 611 11.09 245 612 11.10 245 613 11.11 245 614 11.12 245 615 11.13 245 616 11.14 245 617 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Drawdown Within 72-Hours Pond 1P Rv = Recharge Volume, cu.ft. (see above) K = Saturated Hydraulic Conductivity, in/hr (from Rawls Table) Bottom Area = Area of Infiltration System Bottom, sq.ft. = !"# = 130 %&. . 0.69 /ℎ) 244 +. . = = 0.77 ℎ-&) o 0.77 hours < 72 hours Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.03 WATER QUALITY VOLUME CALCULATIONS Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Water Quality Volume Calculation VWQ = (DWQ/12 inches/foot) * (AIMP square feet) VWQ = Required Water Quality Volume (in cubic feet) DWQ = Water Quality Depth: 0.5-inch AIMP = Total Impervious Area (in acres) used for driveways, parking, etc. Underground Infiltration Systems and Bio-Retention Areas AIMP = 2,596 sq.ft. VWQ = (0.5 inches/12 inches/foot) * (2,596 sq.ft.) VWQ = 108 cubic feet (required volume), provided volume = 617 cubic feet in Underground Infiltration System (refer to the HydroCAD storage tables provided in groundwater recharge section). Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.04 PIPE SIZING CALCULATIONS PROJECT NAME:#REF! DATE:#REF! CALCS BY:#REF! CHECKED BY:#REF! Rational Method Flow Rate Pipe Capacity Analysis Total Area, A (ac) =0.02 Design Flow Rate, Q (cfs) =0.12 Manning's Equation Q = VA = (1.49/n )AR2/3S1/2 [cfs] Area Impervious (ac) =0.02 Pipe Material (HDPE, RCP, PVC) =PVC (1.49/n )AR2/3S1/2 =0.21 cfs Area Grass (ac) =0.00 Pipe Size (in) =4 Area Woods (ac) = 0.00 Pipe Slope, S (%) =1.00%Pipe Sufficiently Sized:Yes Time of Concentration, Tc (min) =6.0 Manning's Roughness Coefficient, n =0.012 Return Frequency Period (years) =25 Wetted Area, A (sf) =0.09 Cover Characteristics, C =0.90 Wetted Perimeter, P (ft) = 1.05 Rainfall Intensity, i (in/hr) =5.89 Hydraulic Radius, R [A/P] (ft) = 0.08 R2/3 =0.191 Q = CiA [cfs] Pipe Slope, S (ft/ft) = 0.010 Flow Rate, Q (cfs) =0.12 S1/2 =0.10 Velocity, V (ft/s) = 2.37 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.05 WQU SIZING CALCULATIONS PROPRIETARY STORMWATER SIZING CALCULATION Project No.Calc By Subject Date Location Checked by Date WQU-1 Q50 = (qu)(A)(WQV) Q50 = peak flow rate assocated with the first 1/2-inch of runoff qu = the unit peak discharge (csm/in) A = imprevious surface drainage area (square miles) WQV = water quality volume in watershed Step 1:Determine WQV Impervious Area = 1,696 sf 0.0001 square miles WQV = 848 cf Step 2:Determine tc tc = 6 min Step 3:Determine qu using DEP figure 2 qu = 774 csm/in Step 4: Calculate Q50 Q50 =0.02 cfs 50711.00 WQU Peak Flow Rate Calc Tidewater Motor Lodge M/ Morrison 10/7/2024 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA 6.06 ILLICIT DISCHARGE COMPLIANCE STATEMENT Stormwater Report Tidewater Motor Lodge West Yarmouth, MA Illicit Discharge Compliance Statement This statement is to document that, to the best of my knowledge and belief, there are no and will be no illicit discharges to the stormwater management systems or protected wetland resource areas for the improvements to Tidewater Motor Lodge in West Yarmouth, Massachusetts. Authorized Signature/Title Date Stormwater Report Tidewater Motor Lodge West Yarmouth, MA APPENDIX A USGS LOCUS MAP Stormwater Report Tidewater Motor Lodge West Yarmouth, MA APPENDIX B FEMA MAP Stormwater Report Tidewater Motor Lodge West Yarmouth, MA APPENDIX C WEB SOIL SURVEY Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/7/2024 Page 1 of 4 46 1 2 2 3 0 46 1 2 2 7 0 46 1 2 3 1 0 46 1 2 3 5 0 46 1 2 3 9 0 46 1 2 4 3 0 46 1 2 4 7 0 46 1 2 5 1 0 46 1 2 5 5 0 46 1 2 5 9 0 46 1 2 2 3 0 46 1 2 2 7 0 46 1 2 3 1 0 46 1 2 3 5 0 46 1 2 3 9 0 46 1 2 4 3 0 46 1 2 4 7 0 46 1 2 5 1 0 46 1 2 5 5 0 46 1 2 5 9 0 394830 394870 394910 394950 394990 395030 395070 394830 394870 394910 394950 394990 395030 395070 41° 39' 29'' N 70 ° 1 5 ' 4 7 ' ' W 41° 39' 29'' N 70 ° 1 5 ' 3 5 ' ' W 41° 39' 17'' N 70 ° 1 5 ' 4 7 ' ' W 41° 39' 17'' N 70 ° 1 5 ' 3 5 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 19N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:1,810 if printed on A portrait (8.5" x 11") 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 20, Sep 12, 2023 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 10, 2022—Jun 30, 2022 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/7/2024 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 1 Water 0.3 2.0% 66A Ipswich - Pawcatuck - Matunuck complex, 0 to 2 percent slopes, very frequently flooded A/D 0.8 5.1% 252A Carver coarse sand, 0 to 3 percent slopes A 0.9 5.5% 252B Carver coarse sand, 3 to 8 percent slopes A 13.2 80.5% 607 Water, saline 0.9 5.6% 665 Udipsamments, smoothed 0.2 1.4% Totals for Area of Interest 16.4 100.0% Hydrologic Soil Group—Barnstable County, Massachusetts Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 8/7/2024 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 8/7/2024 Page 4 of 4 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA APPENDIX D NOAA 14 PRECIPITATION TABLES NOAA Atlas 14, Volume 10, Version 3 Location name: West Yarmouth, Massachusetts, USA* Latitude: 41.6566°, Longitude: -70.2617° Elevation: 13 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Sandra Pavlovic, Michael St. Laurent, Carl Trypaluk, Dale Unruh, Orlan Wilhite NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.265 (0.216‑0.324) 0.336 (0.273‑0.410) 0.452 (0.367‑0.554) 0.547 (0.440‑0.675) 0.679 (0.526‑0.882) 0.777 (0.588‑1.03) 0.882 (0.646‑1.22) 1.01 (0.687‑1.42) 1.20 (0.779‑1.75) 1.36 (0.862‑2.02) 10-min 0.376 (0.306‑0.459) 0.476 (0.387‑0.582) 0.640 (0.518‑0.783) 0.775 (0.623‑0.956) 0.962 (0.745‑1.25) 1.10 (0.833‑1.46) 1.25 (0.916‑1.74) 1.43 (0.973‑2.01) 1.70 (1.10‑2.48) 1.93 (1.22‑2.87) 15-min 0.442 (0.360‑0.540) 0.560 (0.455‑0.684) 0.753 (0.610‑0.923) 0.912 (0.733‑1.12) 1.13 (0.876‑1.47) 1.30 (0.979‑1.72) 1.47 (1.08‑2.04) 1.68 (1.14‑2.36) 2.00 (1.30‑2.91) 2.27 (1.44‑3.37) 30-min 0.657 (0.535‑0.802) 0.828 (0.673‑1.01) 1.11 (0.897‑1.36) 1.34 (1.08‑1.65) 1.66 (1.28‑2.15) 1.89 (1.43‑2.52) 2.15 (1.57‑2.98) 2.45 (1.67‑3.45) 2.92 (1.90‑4.25) 3.31 (2.10‑4.92) 60-min 0.872 (0.710‑1.06) 1.10 (0.891‑1.34) 1.46 (1.18‑1.79) 1.76 (1.42‑2.17) 2.18 (1.69‑2.83) 2.49 (1.88‑3.31) 2.82 (2.07‑3.92) 3.22 (2.20‑4.54) 3.84 (2.49‑5.59) 4.36 (2.76‑6.48) 2-hr 1.23 (1.01‑1.49) 1.52 (1.25‑1.85) 2.01 (1.64‑2.45) 2.41 (1.95‑2.95) 2.96 (2.31‑3.81) 3.37 (2.57‑4.44) 3.82 (2.82‑5.24) 4.35 (2.99‑6.05) 5.16 (3.39‑7.43) 5.85 (3.74‑8.59) 3-hr 1.47 (1.21‑1.77) 1.81 (1.49‑2.19) 2.36 (1.94‑2.87) 2.83 (2.30‑3.45) 3.46 (2.71‑4.43) 3.93 (3.01‑5.15) 4.44 (3.30‑6.06) 5.05 (3.49‑6.97) 5.97 (3.94‑8.53) 6.75 (4.34‑9.83) 6-hr 1.92 (1.59‑2.31) 2.34 (1.93‑2.80) 3.01 (2.48‑3.62) 3.56 (2.92‑4.32) 4.33 (3.42‑5.49) 4.90 (3.78‑6.34) 5.52 (4.11‑7.41) 6.23 (4.34‑8.50) 7.30 (4.87‑10.3) 8.19 (5.32‑11.8) 12-hr 2.41 (2.01‑2.87) 2.88 (2.40‑3.44) 3.65 (3.03‑4.37) 4.29 (3.53‑5.16) 5.17 (4.10‑6.47) 5.83 (4.52‑7.44) 6.52 (4.88‑8.62) 7.30 (5.14‑9.84) 8.43 (5.69‑11.7) 9.36 (6.14‑13.3) 24-hr 2.87 (2.40‑3.39) 3.38 (2.84‑4.01) 4.23 (3.53‑5.02) 4.93 (4.09‑5.88) 5.89 (4.70‑7.30) 6.62 (5.16‑8.35) 7.38 (5.55‑9.60) 8.20 (5.84‑10.9) 9.35 (6.37‑12.8) 10.3 (6.81‑14.4) 2-day 3.26 (2.76‑3.84) 3.81 (3.22‑4.48) 4.71 (3.96‑5.56) 5.46 (4.56‑6.46) 6.48 (5.21‑7.94) 7.26 (5.70‑9.05) 8.06 (6.10‑10.3) 8.90 (6.40‑11.7) 10.1 (6.93‑13.6) 11.0 (7.36‑15.1) 3-day 3.54 (3.00‑4.14) 4.10 (3.47‑4.80) 5.00 (4.22‑5.88) 5.76 (4.83‑6.80) 6.80 (5.49‑8.29) 7.59 (5.99‑9.41) 8.40 (6.39‑10.7) 9.26 (6.70‑12.1) 10.4 (7.23‑14.0) 11.4 (7.66‑15.5) 4-day 3.78 (3.21‑4.40) 4.34 (3.68‑5.06) 5.25 (4.44‑6.15) 6.01 (5.05‑7.07) 7.05 (5.72‑8.57) 7.85 (6.21‑9.69) 8.66 (6.62‑11.0) 9.54 (6.92‑12.4) 10.7 (7.48‑14.4) 11.7 (7.92‑15.9) 7-day 4.41 (3.77‑5.11) 4.97 (4.25‑5.78) 5.90 (5.02‑6.87) 6.67 (5.64‑7.80) 7.73 (6.30‑9.31) 8.53 (6.80‑10.4) 9.36 (7.20‑11.8) 10.2 (7.49‑13.2) 11.4 (8.03‑15.1) 12.4 (8.46‑16.7) 10-day 5.00 (4.29‑5.78) 5.59 (4.79‑6.46) 6.54 (5.59‑7.59) 7.34 (6.23‑8.55) 8.43 (6.91‑10.1) 9.27 (7.42‑11.3) 10.1 (7.81‑12.6) 11.0 (8.10‑14.1) 12.2 (8.63‑16.0) 13.2 (9.04‑17.6) 20-day 6.81 (5.88‑7.81) 7.49 (6.46‑8.61) 8.61 (7.40‑9.91) 9.54 (8.15‑11.0) 10.8 (8.92‑12.8) 11.8 (9.50‑14.2) 12.8 (9.91‑15.7) 13.7 (10.2‑17.3) 15.0 (10.7‑19.3) 15.8 (11.0‑20.8) 30-day 8.37 (7.26‑9.57) 9.14 (7.92‑10.5) 10.4 (8.99‑11.9) 11.5 (9.84‑13.2) 12.9 (10.7‑15.2) 14.0 (11.3‑16.7) 15.1 (11.8‑18.4) 16.2 (12.1‑20.2) 17.4 (12.5‑22.3) 18.3 (12.8‑23.8) 45-day 10.4 (9.04‑11.8) 11.3 (9.80‑12.8) 12.7 (11.0‑14.5) 13.9 (12.0‑16.0) 15.6 (12.9‑18.2) 16.9 (13.7‑20.0) 18.1 (14.1‑21.8) 19.2 (14.5‑23.9) 20.5 (14.8‑26.1) 21.4 (15.0‑27.6) 60-day 12.1 (10.6‑13.8) 13.1 (11.4‑14.9) 14.7 (12.8‑16.7) 16.0 (13.8‑18.3) 17.8 (14.9‑20.8) 19.3 (15.7‑22.7) 20.6 (16.1‑24.7) 21.8 (16.5‑26.9) 23.2 (16.9‑29.3) 24.1 (17.0‑30.9) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequencyestimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates atupper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical 10/3/24, 12:20 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=41.6566&lon=-70.2617&data=depth&units=english&series=pds 1/4 Back to Top Maps & aerials Small scale terrain 10/3/24, 12:20 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=41.6566&lon=-70.2617&data=depth&units=english&series=pds 2/4 Large scale terrain Large scale map Large scale aerial + – 3km 2mi + – 100km 60mi + – 100km 60mi 10/3/24, 12:20 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=41.6566&lon=-70.2617&data=depth&units=english&series=pds 3/4 Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer + – 100km 60mi 10/3/24, 12:20 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=41.6566&lon=-70.2617&data=depth&units=english&series=pds 4/4 Stormwater Report Tidewater Motor Lodge West Yarmouth, MA APPENDIX E STORMWATER CHECKLIST Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A. Introduction 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 2 of 8 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 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 3 of 8 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 4 of 8 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 5 of 8 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 6 of 8 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 7 of 8 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. Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report swcheck.doc • 04/01/08 Stormwater Report Checklist • Page 8 of 8 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.