The URL can be used to link to this page

All Hampden Storm Water Report 9-14-2020pp 9-14-2020 Northampton, MA 32 Perkins Ave Pioneer Development, LLC Prepeared For: Northampton, MA 36 Hampden Ave Location: Stormwater Report Notice Of Intent 413-626-8167 Chesterfield, MA 01012 PO Box 262 The Engineer Group, LLC The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Table of Contents Table of Contents ..... 1 List of Figures ............. 2 Checklist for Stormwater Report . 3 Stormwater Report Narrative 4 Project Description 4 Site Description and Existing Drainage Conditions 4 Proposed Drainage Conditions 6 Regulatory Compliance Massachusetts Department of Environmental Protection (DEP) - Stormwater Management Standards 8 Appendix .. Appendix A Standard 2 Peak Rate Calculations Hydrocad Appendix B Standard 3 Recharge Supporting Information Appendix C Standard 4 Water Quality Calculations Cultec ISO Appendix D Standard 8 CPPP and ES plan Appendix E Standard 9 Operation Maintenance Plan and Cultec Separator Row 9-14-2020 Page 1 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report List of Figures Figure No. Description 1 Site Locus Map 2 Site Survey 3 SCS Soils Map and Report 4 Wetland/Flood Plain Boundary Map 5 Existing Conditions, Proposed Conditions and Stormwater, See full Size Drawings 9-14-2020 Page 2 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Checklist for Stormwater Report 9-14-2020 Page 3 of 10 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include: ·The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report. ·Applicant/Project Name ·Project Address ·Name of Firm and Registered Professional Engineer that prepared the Report ·Long-Term Pollution Prevention Plan required by Standards 4-6 ·Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 ·Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report 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 Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 2 of 8 6/8/2020 6-8-2020 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe):Cultec “Separator Row”, Rain Barrels 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 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; 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 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. Hampden swchecklist 6-8-2020.odt • 04/01/08 Stormwater Report Checklist • Page 8 of 8 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Stormwater Report Narrative This Stormwater Report has been prepared to demonstrate compliance with the Massachusetts Stormwater Management Standards in accordance with the Massachusetts Wetlands Protection Act Regulations (310 CMR 10.00) and Water Quality Certification Regulations (314 CMR 9.00). This report also demonstrates compliance with the City of Northampton rules and regulations for wetlands, and stormwater design and mitigation. Project Description Pioneer Development LLC is proposing to construct 3 additional dwellings units, situated on a previously developed parcel at 36 Hampden St, Northampton Massachusetts (the Project) which has 2 dwelling units existing on the property at present time. The Project proposes 3 new units, a paved driveway with 5 new parking spaces, removal of a garage structure to create 3 new parking spaces on the remaining garage slab, ancillary landscape improvements. The project is not considered a Land Use with Higher Potential Pollutant Loads (LUHPPL) as defined in 3.10 CMR 10.04 and 314 CMR 9.02. The total disturbance is 0.323 acres which does not require a NPDS Construction General Permit. Site Description The Site is currently an approximately 1.77-acre parcel of land located at the end of Hampden St, Northampton, Massachusetts (See Figure 1, and 2). It is located near the intersection of Hampden Street and Reed Street, at the south- eastern terminus of Hampden St. The Site borders on the north side of Arcadia Wildlife Sanctuary, and borders an abandoned section of the old Mill River bed (See Figure2). Figure 2 shows old lot lines numbered 11, 12, 13, and 14. The site owners are proposing to donate the old parcel numbered 14 in Figure 2 to 9-14-2020 Page 4 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report the Mass Audubon Society to be added to the Arcadia Wildlife Sanctuary. This will bring the new lot size to 0.63 acres. The area inside the bounds of the Erosion Sediment Controls are proposed to be 0.323 acres. There is a Bordering Vegetated Wetland (BVW) resource and a 100 year flood plain on the south side of the existing site. Work is proposed within the 100' boundary of the BVW and within the 40' Northampton offset of the Flood Plain boundary on the site, as well as a section of the 35' Northampton BVW boundary to expand the paving for a parking space on the south side of the existing garage slab, and to mow some of the Japanese Knot Weed to be replaced with grass for erosion control, water filtration, and maintenance (figure 4). SCS Soil Survey map(Figure 3) shows the soils comprised of 745C, Hinckley- Merrimac-Urban land complex, 3 to 15 percent slopes, which is listed as Class A in the Soils Report, and 52A, Freetown muck, central lowland, 0 to 1 percent slopes, which is listed in the Soils Report as Hydrologic Soil Group (HSG) B/D Soils. Soils analysis in the lowland portion of the site for wetland delineation, confirm the soil type to be consistent with the Freetown Muck with exception that the muck layer below the peat is silty clay, instead of Muck. The HSG Group in the lowland area is HSG D. Probe soil tests of the upland portion of the site show the soil to be consistent with the Hinckley-Merrimac-Urban land complex, sandy gravel, sand, and loamy sand. The HSG of the upland portion of the site, and where all disturbance is proposed is HSG A. Existing hydrology of the upland sand and gravel soil allows water to infiltrate and seep downward until it encounters the underlying clay/silt layer where it is forced outward toward the old Mill River bed. In spring the water seeps along the bottom of the slope, and across the surface to the old Mill River Bed. There is an existing outfall of a Municipal stormwater pipe which measures approx 10'' dia. Located on the west side of the property, near the bottom of the slope. It is steel corrugated and collapsed at the end. Above the municipal pipe is an existing outfall of a privately owned storm 4" PVC drain coming from an existing basin located in the existing driveway to the site. There is some minor erosion to the wetland at the outfall of the municipal pipe. To the east of the lot, on the neighboring lot, near the existing garage, is a seep which is creating a visibly wet area as observed throughout the summer (Figure 4). The wet area drains into the wetland and runs toward the old Mill River bed. The BVW 9-14-2020 Page 5 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report generally follows the toe of the slope, until it runs east, where it disappears under debris, then reappears up the slope on the adjacent lot. (Figure 4). Proposed Drainage Conditions The Project is a redevelopment of the Site, so as stated in Standard 7 of the Massachusetts Stormwater Standards, it is subject to Standards 2, 3, 4, 5, and 6 to the maximum extent practicable. The Site is subject Standard 2; an overview of planned drainage is provided (Figure 6). Runoff on the site would be split between two drainage areas much as it exists currently. In the northern part of the Site, the grass areas, paved areas, and half the roofs of the existing and proposed buildings will be collected via a deep sump catch basin then piped through a water quality inlet deep sum hooded basin. Water quality will then be provided by a proprietary Cultec Separator Row System within 8 Galley type chambers, and 24 Galleys in standard fashion installed under the new proposed paved driveway. The Separator Row and other chambers will be installed in a bed of stone which will be wrapped with an HDPE membrane to prevent infiltration on the site and to keep stormwater separated form ground water. (figure 6) The chamber/stone system proposed will drain through an orifice outlet control located in a manhole, then connect to the municipal pipe which will outfall in the wetland in the existing location at the toe of the slope. The City of Northampton DPW has informed us that the collapsed drain will be repaired in the future. The stormwater for the southern part of the Site would be as it exists today. Roof leaders will drain to splash blocks which will overflow disconnected into mulched or grassy areas. The decks in the rear of the buildings will be also disconnected and run off into the grass area behind the building. The system has been designed to mitigate the 2, and 10 year storms for peak runoff rate. Standard 6 Recharge will not be accomplished due to lack of space on the site. When discounting the lot set backs, and setback from foundations listed in the Massachusetts Storm Water Manual, there is no space left to safely locate a recharge system. (See the appendix for drawing) 9-14-2020 Page 6 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Environmentally Sensitive and Low Impact Development (LID) Techniques Low Impact Development (LID) techniques and stormwater Best Management Practices (BMPs) implemented into the site design include: The new buildings are designed clustered to minimize impervious area, and maximize pervious. walkways and some parking areas have been designed to occupy the smallest footprint possible on the site. Rain barrels are proposed for the front of the building. Environmentally Sensitive Elements Environmentally sensitive elements include: A stand of Japanese Knot Weed (invasive species) on the south slope which is proposed to be partially mowed and replaced with grass, then maintained by mowing to provide a filter strip before overland waters enter the wetland. It should be noted that the Hydraulic analysis includes the neighbors property to the north, since it drains primarily to the inlet location existing and proposed. The drainage mitigation for 2 and 10 yr storms encompasses this additional property as well. Donation of the tract of land for conservation will add to the Arcadia Wildlife Sanctuary for public preservation. Stormwater runoff from all impervious surfaces in proposed conditions will receive treatment for stormwater quality prior to discharge to the BVW. Under existing conditions, there is no treatment provided for stormwater runoff. The Site has been designed with a stormwater management system to the maximum extent practicable that has been developed in accordance with the Massachusetts Stormwater Standards. 9-14-2020 Page 7 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Massachusetts Department of Environmental Protection (DEP) - Stormwater Management Standards As demonstrated below, the proposed Project complies with the DEP Stormwater Management Standards. Standard 1: No New Untreated Discharges or Erosion to Wetlands The Project has been designed to fully comply with Standard 1. The Best Management Practices (BMPs) included in the proposed stormwater management system have been designed in accordance with the Massachusetts Stormwater Handbook. Supporting information and computations demonstrating that no new untreated discharges will result from the Project are presented through compliance with Standards 4 through 6. Standard 2: Peak Rate Attenuation The project is a redevelopment, and it has been designed to comply with Standard 2 to account for the proposed increase in impervious area on the site. The rainfall-runoff response of the Site under existing and proposed conditions was evaluated for storm events with recurrence intervals of 2, 10, 25 and 100- years. Drainage areas used in the analyses are shown on page 4 of the drawings. The HydroCAD model is based on the NRCS Technical Release 20 (TR-20) Model for Project Formulation Hydrology. Printouts of the HydroCAD analyses are included in the Appendix. A table on Drawing 4 presents a summary of the existing and proposed conditions peak discharge rates. The results of the analysis indicate that there is no increase in peak discharge rates between the pre- and post-development for the 2yr, and 10 yr storms. Standard 3: Stormwater Recharge The project is a redevelopment, and has not been designed to comply with 9-14-2020 Page 8 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Standard 3. Though the soil analysis' showed recharge was possible, the limitations of lot size prohibit a system to be installed due to setback requirements in the Stormwater Manual which are required for recharge BMP's. In order to recharge as much as practical, we have designed parking in front of the existing building and all walkways with a minimal footprint, and clustered the buildings. Standard 4: Water Quality The Project has been designed to comply with Standard 4. The proposed stormwater management system implements a treatment train of BMPs that has been designed to provide >80% TSS removal of stormwater runoff from all proposed impervious surfaces. Computations and supporting information, including a Long-Term Pollution Prevention Plan, are included in the Appendix. Standard 5: Land Uses with Higher Potential Pollutant Loads (LUHPPLs) The project is not subject to uses with Higher Potential Pollutant Loads. Traffic is under 1000 trips per day. Standard 6: Critical Areas The Project will not discharge new stormwater near or to a critical area. The outfall in the BVW where the discharge is going, is existing. No new outfalls are proposed. Standard 7: Redevelopments and Other Projects Subject to the Standards only to the Maximum Extent Practicable Though the Project is a redevelopment, it has been designed to comply with Stormwater Management Standards 1,2,4,5,6. Standards 8-10 have been or will be met completely before construction begins. 9-14-2020 Page 9 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Controls The Project will disturb a maximum of 0.323 acres of land and is therefore not required to obtain coverage under the Environmental Protection Agency (EPA) National Pollutant Discharge Elimination System (NPDES) with a Construction General Permit. Construction Period Pollution Prevention and Erosion and Sediment Controls (CPPPES) are submitted in the plans. Recommended (CPPPES) controls are to be submitted, and approved by the Municipality before land disturbance begins. Standard 9: Operation and Maintenance Plan In compliance with Standard 9, a Post Construction Stormwater Operation and Maintenance (O&M) Plan has been developed for the Project. The O&M Plan is included in the Appendix. Standard 10: Prohibition of Illicit Discharges No Illicit Discharges exist, and none are proposed for this project. 9-14-2020 Page 10 of 10 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX A Standard 2 Peak Rate Calculations HydroCAD 5-30-2020 1S S1 2S S2 1R Eroded Channel 1MH Drain in Drive 1L Flow over Parking Exist Total Runoff Routing Diagram for 36 Hampden Northampton r2 Prepared by The Engineer Group, LLC, Printed 9/14/2020 HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link Existing Table of Contents36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Rainfall Events Listing 3 Area Listing (all nodes) 4 Soil Listing (all nodes) 5 Ground Covers (all nodes) 6 Pipe Listing (all nodes) 2-Year Event 7 Node Listing 8 Subcat 1S: S1 10 Subcat 2S: S2 12 Reach 1R: Eroded Channel 13 Pond 1MH: Drain in Drive 15 Link 1L: Flow over Parking 16 Link Exist: Total Runoff 10-Year Event 17 Node Listing 18 Subcat 1S: S1 20 Subcat 2S: S2 22 Reach 1R: Eroded Channel 23 Pond 1MH: Drain in Drive 25 Link 1L: Flow over Parking 26 Link Exist: Total Runoff 25-Year Event 27 Node Listing 28 Subcat 1S: S1 30 Subcat 2S: S2 32 Reach 1R: Eroded Channel 33 Pond 1MH: Drain in Drive 35 Link 1L: Flow over Parking 36 Link Exist: Total Runoff 100-Year Event 37 Node Listing 38 Subcat 1S: S1 40 Subcat 2S: S2 42 Reach 1R: Eroded Channel 43 Pond 1MH: Drain in Drive 45 Link 1L: Flow over Parking 46 Link Exist: Total Runoff Existing 36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 2HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing Event#Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 1-Year Type III 24-hr Default 24.00 1 2.55 2 2 2-Year Type III 24-hr Default 24.00 1 3.09 2 3 5-Year Type III 24-hr Default 24.00 1 4.11 2 4 10-Year Type III 24-hr Default 24.00 1 4.95 2 5 25-Year Type III 24-hr Default 24.00 1 6.12 2 6 50-Year Type III 24-hr Default 24.00 1 6.97 2 7 100-Year Type III 24-hr Default 24.00 1 7.91 2 Existing 36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 3HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.148 39 >75% Grass cover, Good, HSG A (1S, 2S) 0.170 35 Brush, Fair, HSG A (2S) 0.237 77 Brush, Fair, HSG D (2S) 0.077 96 Gravel surface, HSG A (1S) 0.094 98 Paved parking, HSG A (1S) 0.037 98 Roofs, HSG A Unconnected (1S) 0.013 98 Unconnected pavement, HSG A (2S) 0.046 98 Unconnected roofs, HSG A (2S) 0.821 68 TOTAL AREA Existing 36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 4HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.584 HSG A 1S, 2S 0.000 HSG B 0.000 HSG C 0.237 HSG D 2S 0.000 Other 0.821 TOTAL AREA Existing 36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 5HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.148 0.000 0.000 0.000 0.000 0.148 >75% Grass cover, Good 1S, 2S 0.170 0.000 0.000 0.237 0.000 0.407 Brush, Fair 2S 0.077 0.000 0.000 0.000 0.000 0.077 Gravel surface 1S 0.094 0.000 0.000 0.000 0.000 0.094 Paved parking 1S 0.037 0.000 0.000 0.000 0.000 0.037 Roofs 1S 0.013 0.000 0.000 0.000 0.000 0.013 Unconnected pavement 2S 0.046 0.000 0.000 0.000 0.000 0.046 Unconnected roofs 2S 0.584 0.000 0.000 0.237 0.000 0.821 TOTAL AREA Existing 36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 6HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line#Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 1MH 135.00 115.30 137.0 0.1438 0.010 4.0 0.0 0.0 Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 7HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=12,343 sf 46.12% Impervious Runoff Depth=1.45"Subcatchment 1S: S1 Flow Length=172' Tc=2.4 min CN=82 Runoff=0.55 cfs 0.034 af Runoff Area=23,398 sf 10.80% Impervious Runoff Depth=0.33"Subcatchment 2S: S2 Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 Runoff=0.11 cfs 0.015 af Avg. Flow Depth=0.15' Max Vel=2.49 fps Inflow=0.53 cfs 0.034 afReach 1R: Eroded Channel n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs Outflow=0.53 cfs 0.034 af Peak Elev=137.76' Storage=6 cf Inflow=0.55 cfs 0.034 afPond 1MH: Drain in Drive Primary=0.53 cfs 0.034 af Secondary=0.00 cfs 0.000 af Outflow=0.53 cfs 0.034 af Inflow=0.00 cfs 0.000 afLink 1L: Flow over Parking Primary=0.00 cfs 0.000 af Inflow=0.62 cfs 0.049 afLink Exist: Total Runoff Primary=0.62 cfs 0.049 af Total Runoff Area = 0.821 ac Runoff Volume = 0.049 af Average Runoff Depth = 0.72" 77.00% Pervious = 0.632 ac 23.00% Impervious = 0.189 ac Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 8HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: S1 Runoff =0.55 cfs @ 12.04 hrs, Volume=0.034 af, Depth=1.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.09" Area (sf)CN Description 3,311 39 >75% Grass cover, Good, HSG A *633 98 Roofs, HSG A Unconnected 3,348 98 Paved parking, HSG A *3,339 96 Gravel surface, HSG A *967 98 Roofs, HSG A Unconnected *745 98 Paved parking, HSG A 12,343 82 Weighted Average 6,650 53.88% Pervious Area 5,693 46.12% Impervious Area 1,600 28.10% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.8 100 0.0250 0.90 Sheet Flow, parking => drain n= 0.020 P2= 3.00" 0.6 72 0.0174 2.12 Shallow Concentrated Flow, gar - drain2 Unpaved Kv= 16.1 fps 2.4 172 Total Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 9HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: S1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 2-Year Rainfall=3.09" Runoff Area=12,343 sf Runoff Volume=0.034 af Runoff Depth=1.45" Flow Length=172' Tc=2.4 min CN=82 0.55 cfs Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 10HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: S2 Runoff =0.11 cfs @ 12.10 hrs, Volume=0.015 af, Depth=0.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.09" Area (sf)CN Adj Description 1,249 98 Unconnected roofs, HSG A 3,145 39 >75% Grass cover, Good, HSG A 7,415 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 545 98 Unconnected pavement, HSG A *733 98 Unconnected roofs, HSG A 23,398 61 59 Weighted Average, UI Adjusted 20,871 89.20% Pervious Area 2,527 10.80% Impervious Area 2,527 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.4 35 0.2200 0.24 Sheet Flow, Drive to brush Grass: Dense n= 0.240 P2= 3.00" 1.3 93 0.2200 1.17 Shallow Concentrated Flow, Brush to Property edge Forest w/Heavy Litter Kv= 2.5 fps 3.7 128 Total Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 11HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.12 0.115 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 2-Year Rainfall=3.09" Runoff Area=23,398 sf Runoff Volume=0.015 af Runoff Depth=0.33" Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 0.11 cfs Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 12HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Reach 1R: Eroded Channel Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 1.45" for 2-Year event Inflow =0.53 cfs @ 12.05 hrs, Volume=0.034 af Outflow =0.53 cfs @ 12.04 hrs, Volume=0.034 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Max. Velocity= 2.49 fps, Min. Travel Time= 0.1 min Avg. Velocity = 0.89 fps, Avg. Travel Time= 0.4 min Peak Storage= 4 cf @ 12.04 hrs Average Depth at Peak Storage= 0.15' , Surface Width= 2.17' Bank-Full Depth= 2.00' Flow Area= 10.7 sf, Capacity= 138.47 cfs 8.00' x 2.00' deep Parabolic Channel, n= 0.040 Winding stream, pools & shoals Length= 20.0' Slope= 0.1000 '/' Inlet Invert= 114.00', Outlet Invert= 112.00' Reach 1R: Eroded Channel Inflow Outflow Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.283 ac Avg. Flow Depth=0.15' Max Vel=2.49 fps n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs 0.53 cfs 0.53 cfs Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 13HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1MH: Drain in Drive Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 1.45" for 2-Year event Inflow =0.55 cfs @ 12.04 hrs, Volume=0.034 af Outflow =0.53 cfs @ 12.05 hrs, Volume=0.034 af, Atten= 2%, Lag= 0.7 min Primary =0.53 cfs @ 12.05 hrs, Volume=0.034 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 137.76' @ 12.05 hrs Surf.Area= 7 sf Storage= 6 cf Plug-Flow detention time= 0.3 min calculated for 0.034 af (100% of inflow) Center-of-Mass det. time= 0.1 min ( 834.8 - 834.6 ) Volume Invert Avail.Storage Storage Description #1 135.00'131 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 135.00 2 0 0 137.75 2 6 6 138.00 200 25 31 138.20 800 100 131 Device Routing Invert Outlet Devices #1 Primary 135.00'4.0" Round Culvert L= 137.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 135.00' / 115.30' S= 0.1438 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf #2 Secondary 138.00'10.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.53 cfs @ 12.05 hrs HW=137.76' TW=114.15' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.53 cfs @ 6.12 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=135.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 14HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1MH: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.283 ac Peak Elev=137.76' Storage=6 cf 0.55 cfs 0.53 cfs 0.53 cfs 0.00 cfs Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 15HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Flow over Parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 1L: Flow over Parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Existing Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 16HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Exist: Total Runoff Inflow Area =0.821 ac,23.00% Impervious, Inflow Depth = 0.72" for 2-Year event Inflow =0.62 cfs @ 12.06 hrs, Volume=0.049 af Primary =0.62 cfs @ 12.06 hrs, Volume=0.049 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Exist: Total Runoff Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 Inflow Area=0.821 ac 0.62 cfs 0.62 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 17HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=12,343 sf 46.12% Impervious Runoff Depth=3.03"Subcatchment 1S: S1 Flow Length=172' Tc=2.4 min CN=82 Runoff=1.15 cfs 0.072 af Runoff Area=23,398 sf 10.80% Impervious Runoff Depth=1.21"Subcatchment 2S: S2 Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 Runoff=0.73 cfs 0.054 af Avg. Flow Depth=0.15' Max Vel=2.54 fps Inflow=0.57 cfs 0.067 afReach 1R: Eroded Channel n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs Outflow=0.57 cfs 0.067 af Peak Elev=138.07' Storage=67 cf Inflow=1.15 cfs 0.072 afPond 1MH: Drain in Drive Primary=0.57 cfs 0.067 af Secondary=0.55 cfs 0.004 af Outflow=1.11 cfs 0.072 af Inflow=0.55 cfs 0.004 afLink 1L: Flow over Parking Primary=0.55 cfs 0.004 af Inflow=1.82 cfs 0.126 afLink Exist: Total Runoff Primary=1.82 cfs 0.126 af Total Runoff Area = 0.821 ac Runoff Volume = 0.126 af Average Runoff Depth = 1.84" 77.00% Pervious = 0.632 ac 23.00% Impervious = 0.189 ac Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 18HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: S1 Runoff =1.15 cfs @ 12.04 hrs, Volume=0.072 af, Depth=3.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Description 3,311 39 >75% Grass cover, Good, HSG A *633 98 Roofs, HSG A Unconnected 3,348 98 Paved parking, HSG A *3,339 96 Gravel surface, HSG A *967 98 Roofs, HSG A Unconnected *745 98 Paved parking, HSG A 12,343 82 Weighted Average 6,650 53.88% Pervious Area 5,693 46.12% Impervious Area 1,600 28.10% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.8 100 0.0250 0.90 Sheet Flow, parking => drain n= 0.020 P2= 3.00" 0.6 72 0.0174 2.12 Shallow Concentrated Flow, gar - drain2 Unpaved Kv= 16.1 fps 2.4 172 Total Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 19HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: S1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 10-Year Rainfall=4.95" Runoff Area=12,343 sf Runoff Volume=0.072 af Runoff Depth=3.03" Flow Length=172' Tc=2.4 min CN=82 1.15 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 20HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: S2 Runoff =0.73 cfs @ 12.07 hrs, Volume=0.054 af, Depth=1.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Adj Description 1,249 98 Unconnected roofs, HSG A 3,145 39 >75% Grass cover, Good, HSG A 7,415 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 545 98 Unconnected pavement, HSG A *733 98 Unconnected roofs, HSG A 23,398 61 59 Weighted Average, UI Adjusted 20,871 89.20% Pervious Area 2,527 10.80% Impervious Area 2,527 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.4 35 0.2200 0.24 Sheet Flow, Drive to brush Grass: Dense n= 0.240 P2= 3.00" 1.3 93 0.2200 1.17 Shallow Concentrated Flow, Brush to Property edge Forest w/Heavy Litter Kv= 2.5 fps 3.7 128 Total Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 21HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type III 24-hr 10-Year Rainfall=4.95" Runoff Area=23,398 sf Runoff Volume=0.054 af Runoff Depth=1.21" Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 0.73 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 22HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Reach 1R: Eroded Channel Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 2.85" for 10-Year event Inflow =0.57 cfs @ 12.05 hrs, Volume=0.067 af Outflow =0.57 cfs @ 12.05 hrs, Volume=0.067 af, Atten= 0%, Lag= 0.1 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Max. Velocity= 2.54 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.05 fps, Avg. Travel Time= 0.3 min Peak Storage= 4 cf @ 12.05 hrs Average Depth at Peak Storage= 0.15' , Surface Width= 2.20' Bank-Full Depth= 2.00' Flow Area= 10.7 sf, Capacity= 138.47 cfs 8.00' x 2.00' deep Parabolic Channel, n= 0.040 Winding stream, pools & shoals Length= 20.0' Slope= 0.1000 '/' Inlet Invert= 114.00', Outlet Invert= 112.00' Reach 1R: Eroded Channel Inflow Outflow Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.283 ac Avg. Flow Depth=0.15' Max Vel=2.54 fps n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs 0.57 cfs 0.57 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 23HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1MH: Drain in Drive Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 3.03" for 10-Year event Inflow =1.15 cfs @ 12.04 hrs, Volume=0.072 af Outflow =1.11 cfs @ 12.05 hrs, Volume=0.072 af, Atten= 3%, Lag= 0.9 min Primary =0.57 cfs @ 12.05 hrs, Volume=0.067 af Secondary =0.55 cfs @ 12.05 hrs, Volume=0.004 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 138.07' @ 12.05 hrs Surf.Area= 418 sf Storage= 67 cf Plug-Flow detention time= 0.4 min calculated for 0.072 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 813.7 - 813.4 ) Volume Invert Avail.Storage Storage Description #1 135.00'131 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 135.00 2 0 0 137.75 2 6 6 138.00 200 25 31 138.20 800 100 131 Device Routing Invert Outlet Devices #1 Primary 135.00'4.0" Round Culvert L= 137.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 135.00' / 115.30' S= 0.1438 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf #2 Secondary 138.00'10.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.57 cfs @ 12.05 hrs HW=138.07' TW=114.15' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 6.48 fps) Secondary OutFlow Max=0.55 cfs @ 12.05 hrs HW=138.07' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir (Weir Controls 0.55 cfs @ 0.75 fps) Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 24HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1MH: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.283 ac Peak Elev=138.07' Storage=67 cf 1.15 cfs 1.11 cfs 0.57 cfs 0.55 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 25HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Flow over Parking Inflow =0.55 cfs @ 12.05 hrs, Volume=0.004 af Primary =0.55 cfs @ 12.05 hrs, Volume=0.004 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 1L: Flow over Parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0.55 cfs 0.55 cfs Existing Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 26HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Exist: Total Runoff Inflow Area =0.821 ac,23.00% Impervious, Inflow Depth = 1.84" for 10-Year event Inflow =1.82 cfs @ 12.06 hrs, Volume=0.126 af Primary =1.82 cfs @ 12.06 hrs, Volume=0.126 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Exist: Total Runoff Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.821 ac 1.82 cfs 1.82 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 27HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=12,343 sf 46.12% Impervious Runoff Depth=4.10"Subcatchment 1S: S1 Flow Length=172' Tc=2.4 min CN=82 Runoff=1.54 cfs 0.097 af Runoff Area=23,398 sf 10.80% Impervious Runoff Depth=1.92"Subcatchment 2S: S2 Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 Runoff=1.23 cfs 0.086 af Avg. Flow Depth=0.15' Max Vel=2.54 fps Inflow=0.57 cfs 0.087 afReach 1R: Eroded Channel n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs Outflow=0.57 cfs 0.087 af Peak Elev=138.10' Storage=83 cf Inflow=1.54 cfs 0.097 afPond 1MH: Drain in Drive Primary=0.57 cfs 0.087 af Secondary=0.94 cfs 0.010 af Outflow=1.51 cfs 0.097 af Inflow=0.94 cfs 0.010 afLink 1L: Flow over Parking Primary=0.94 cfs 0.010 af Inflow=2.72 cfs 0.183 afLink Exist: Total Runoff Primary=2.72 cfs 0.183 af Total Runoff Area = 0.821 ac Runoff Volume = 0.183 af Average Runoff Depth = 2.67" 77.00% Pervious = 0.632 ac 23.00% Impervious = 0.189 ac Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 28HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: S1 Runoff =1.54 cfs @ 12.04 hrs, Volume=0.097 af, Depth=4.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.12" Area (sf)CN Description 3,311 39 >75% Grass cover, Good, HSG A *633 98 Roofs, HSG A Unconnected 3,348 98 Paved parking, HSG A *3,339 96 Gravel surface, HSG A *967 98 Roofs, HSG A Unconnected *745 98 Paved parking, HSG A 12,343 82 Weighted Average 6,650 53.88% Pervious Area 5,693 46.12% Impervious Area 1,600 28.10% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.8 100 0.0250 0.90 Sheet Flow, parking => drain n= 0.020 P2= 3.00" 0.6 72 0.0174 2.12 Shallow Concentrated Flow, gar - drain2 Unpaved Kv= 16.1 fps 2.4 172 Total Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 29HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: S1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 25-Year Rainfall=6.12" Runoff Area=12,343 sf Runoff Volume=0.097 af Runoff Depth=4.10" Flow Length=172' Tc=2.4 min CN=82 1.54 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 30HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: S2 Runoff =1.23 cfs @ 12.06 hrs, Volume=0.086 af, Depth=1.92" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.12" Area (sf)CN Adj Description 1,249 98 Unconnected roofs, HSG A 3,145 39 >75% Grass cover, Good, HSG A 7,415 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 545 98 Unconnected pavement, HSG A *733 98 Unconnected roofs, HSG A 23,398 61 59 Weighted Average, UI Adjusted 20,871 89.20% Pervious Area 2,527 10.80% Impervious Area 2,527 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.4 35 0.2200 0.24 Sheet Flow, Drive to brush Grass: Dense n= 0.240 P2= 3.00" 1.3 93 0.2200 1.17 Shallow Concentrated Flow, Brush to Property edge Forest w/Heavy Litter Kv= 2.5 fps 3.7 128 Total Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 31HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 25-Year Rainfall=6.12" Runoff Area=23,398 sf Runoff Volume=0.086 af Runoff Depth=1.92" Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 1.23 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 32HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Reach 1R: Eroded Channel Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 3.68" for 25-Year event Inflow =0.57 cfs @ 12.05 hrs, Volume=0.087 af Outflow =0.57 cfs @ 12.05 hrs, Volume=0.087 af, Atten= 0%, Lag= 0.1 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Max. Velocity= 2.54 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.12 fps, Avg. Travel Time= 0.3 min Peak Storage= 4 cf @ 12.05 hrs Average Depth at Peak Storage= 0.15' , Surface Width= 2.21' Bank-Full Depth= 2.00' Flow Area= 10.7 sf, Capacity= 138.47 cfs 8.00' x 2.00' deep Parabolic Channel, n= 0.040 Winding stream, pools & shoals Length= 20.0' Slope= 0.1000 '/' Inlet Invert= 114.00', Outlet Invert= 112.00' Reach 1R: Eroded Channel Inflow Outflow Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.283 ac Avg. Flow Depth=0.15' Max Vel=2.54 fps n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs 0.57 cfs 0.57 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 33HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1MH: Drain in Drive Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 4.10" for 25-Year event Inflow =1.54 cfs @ 12.04 hrs, Volume=0.097 af Outflow =1.51 cfs @ 12.05 hrs, Volume=0.097 af, Atten= 2%, Lag= 0.7 min Primary =0.57 cfs @ 12.05 hrs, Volume=0.087 af Secondary =0.94 cfs @ 12.05 hrs, Volume=0.010 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 138.10' @ 12.05 hrs Surf.Area= 513 sf Storage= 83 cf Plug-Flow detention time= 0.5 min calculated for 0.097 af (100% of inflow) Center-of-Mass det. time= 0.4 min ( 805.2 - 804.8 ) Volume Invert Avail.Storage Storage Description #1 135.00'131 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 135.00 2 0 0 137.75 2 6 6 138.00 200 25 31 138.20 800 100 131 Device Routing Invert Outlet Devices #1 Primary 135.00'4.0" Round Culvert L= 137.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 135.00' / 115.30' S= 0.1438 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf #2 Secondary 138.00'10.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.57 cfs @ 12.05 hrs HW=138.10' TW=114.15' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 6.51 fps) Secondary OutFlow Max=0.94 cfs @ 12.05 hrs HW=138.10' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir (Weir Controls 0.94 cfs @ 0.90 fps) Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 34HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1MH: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.283 ac Peak Elev=138.10' Storage=83 cf 1.54 cfs 1.51 cfs 0.57 cfs 0.94 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 35HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Flow over Parking Inflow =0.94 cfs @ 12.05 hrs, Volume=0.010 af Primary =0.94 cfs @ 12.05 hrs, Volume=0.010 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 1L: Flow over Parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.94 cfs 0.94 cfs Existing Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 36HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Exist: Total Runoff Inflow Area =0.821 ac,23.00% Impervious, Inflow Depth = 2.67" for 25-Year event Inflow =2.72 cfs @ 12.05 hrs, Volume=0.183 af Primary =2.72 cfs @ 12.05 hrs, Volume=0.183 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Exist: Total Runoff Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)3 2 1 0 Inflow Area=0.821 ac 2.72 cfs 2.72 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 37HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=12,343 sf 46.12% Impervious Runoff Depth=5.77"Subcatchment 1S: S1 Flow Length=172' Tc=2.4 min CN=82 Runoff=2.14 cfs 0.136 af Runoff Area=23,398 sf 10.80% Impervious Runoff Depth=3.16"Subcatchment 2S: S2 Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 Runoff=2.12 cfs 0.141 af Avg. Flow Depth=0.15' Max Vel=2.55 fps Inflow=0.57 cfs 0.114 afReach 1R: Eroded Channel n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs Outflow=0.57 cfs 0.114 af Peak Elev=138.14' Storage=103 cf Inflow=2.14 cfs 0.136 afPond 1MH: Drain in Drive Primary=0.57 cfs 0.114 af Secondary=1.54 cfs 0.022 af Outflow=2.11 cfs 0.136 af Inflow=1.54 cfs 0.022 afLink 1L: Flow over Parking Primary=1.54 cfs 0.022 af Inflow=4.20 cfs 0.278 afLink Exist: Total Runoff Primary=4.20 cfs 0.278 af Total Runoff Area = 0.821 ac Runoff Volume = 0.278 af Average Runoff Depth = 4.06" 77.00% Pervious = 0.632 ac 23.00% Impervious = 0.189 ac Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 38HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1S: S1 Runoff =2.14 cfs @ 12.04 hrs, Volume=0.136 af, Depth=5.77" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Description 3,311 39 >75% Grass cover, Good, HSG A *633 98 Roofs, HSG A Unconnected 3,348 98 Paved parking, HSG A *3,339 96 Gravel surface, HSG A *967 98 Roofs, HSG A Unconnected *745 98 Paved parking, HSG A 12,343 82 Weighted Average 6,650 53.88% Pervious Area 5,693 46.12% Impervious Area 1,600 28.10% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.8 100 0.0250 0.90 Sheet Flow, parking => drain n= 0.020 P2= 3.00" 0.6 72 0.0174 2.12 Shallow Concentrated Flow, gar - drain2 Unpaved Kv= 16.1 fps 2.4 172 Total Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 39HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1S: S1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=12,343 sf Runoff Volume=0.136 af Runoff Depth=5.77" Flow Length=172' Tc=2.4 min CN=82 2.14 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 40HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2S: S2 Runoff =2.12 cfs @ 12.06 hrs, Volume=0.141 af, Depth=3.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Adj Description 1,249 98 Unconnected roofs, HSG A 3,145 39 >75% Grass cover, Good, HSG A 7,415 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 545 98 Unconnected pavement, HSG A *733 98 Unconnected roofs, HSG A 23,398 61 59 Weighted Average, UI Adjusted 20,871 89.20% Pervious Area 2,527 10.80% Impervious Area 2,527 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.4 35 0.2200 0.24 Sheet Flow, Drive to brush Grass: Dense n= 0.240 P2= 3.00" 1.3 93 0.2200 1.17 Shallow Concentrated Flow, Brush to Property edge Forest w/Heavy Litter Kv= 2.5 fps 3.7 128 Total Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 41HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2S: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=23,398 sf Runoff Volume=0.141 af Runoff Depth=3.16" Flow Length=128' Slope=0.2200 '/' Tc=3.7 min UI Adjusted CN=59 2.12 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 42HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Reach 1R: Eroded Channel Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 4.83" for 100-Year event Inflow =0.57 cfs @ 12.04 hrs, Volume=0.114 af Outflow =0.57 cfs @ 12.05 hrs, Volume=0.114 af, Atten= 0%, Lag= 0.1 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Max. Velocity= 2.55 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.20 fps, Avg. Travel Time= 0.3 min Peak Storage= 4 cf @ 12.05 hrs Average Depth at Peak Storage= 0.15' , Surface Width= 2.21' Bank-Full Depth= 2.00' Flow Area= 10.7 sf, Capacity= 138.47 cfs 8.00' x 2.00' deep Parabolic Channel, n= 0.040 Winding stream, pools & shoals Length= 20.0' Slope= 0.1000 '/' Inlet Invert= 114.00', Outlet Invert= 112.00' Reach 1R: Eroded Channel Inflow Outflow Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.283 ac Avg. Flow Depth=0.15' Max Vel=2.55 fps n=0.040 L=20.0' S=0.1000 '/' Capacity=138.47 cfs 0.57 cfs 0.57 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 43HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1MH: Drain in Drive Inflow Area =0.283 ac,46.12% Impervious, Inflow Depth = 5.77" for 100-Year event Inflow =2.14 cfs @ 12.04 hrs, Volume=0.136 af Outflow =2.11 cfs @ 12.04 hrs, Volume=0.136 af, Atten= 1%, Lag= 0.5 min Primary =0.57 cfs @ 12.04 hrs, Volume=0.114 af Secondary =1.54 cfs @ 12.04 hrs, Volume=0.022 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 138.14' @ 12.04 hrs Surf.Area= 634 sf Storage= 103 cf Plug-Flow detention time= 0.5 min calculated for 0.136 af (100% of inflow) Center-of-Mass det. time= 0.4 min ( 795.6 - 795.2 ) Volume Invert Avail.Storage Storage Description #1 135.00'131 cf Custom Stage Data (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 135.00 2 0 0 137.75 2 6 6 138.00 200 25 31 138.20 800 100 131 Device Routing Invert Outlet Devices #1 Primary 135.00'4.0" Round Culvert L= 137.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 135.00' / 115.30' S= 0.1438 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf #2 Secondary 138.00'10.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.57 cfs @ 12.04 hrs HW=138.14' TW=114.15' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 6.56 fps) Secondary OutFlow Max=1.53 cfs @ 12.04 hrs HW=138.14' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir (Weir Controls 1.53 cfs @ 1.06 fps) Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 44HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1MH: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.283 ac Peak Elev=138.14' Storage=103 cf 2.14 cfs 2.11 cfs 0.57 cfs 1.54 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 45HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 1L: Flow over Parking Inflow =1.54 cfs @ 12.04 hrs, Volume=0.022 af Primary =1.54 cfs @ 12.04 hrs, Volume=0.022 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 1L: Flow over Parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 1.54 cfs 1.54 cfs Existing Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Northampton r2 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 46HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Exist: Total Runoff Inflow Area =0.821 ac,23.00% Impervious, Inflow Depth = 4.06" for 100-Year event Inflow =4.20 cfs @ 12.05 hrs, Volume=0.278 af Primary =4.20 cfs @ 12.05 hrs, Volume=0.278 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Exist: Total Runoff Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 Inflow Area=0.821 ac 4.20 cfs 4.20 cfs 1PS PS1 2PS S2 1P Drop Structure MHC1 Drain in Drive Y1 Yard MH 3L Flow over parking 4L Yard overflow Prop Total Proposed Routing Diagram for 36 Hampden Noho Proposed 8-31-2020 Prepared by The Engineer Group, LLC, Printed 9/14/2020 HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link Proposed Table of Contents36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC TABLE OF CONTENTS Project Reports 1 Routing Diagram 2 Rainfall Events Listing 3 Area Listing (all nodes) 4 Soil Listing (all nodes) 5 Ground Covers (all nodes) 6 Pipe Listing (all nodes) 2-Year Event 7 Node Listing 8 Subcat 1PS: PS1 10 Subcat 2PS: S2 12 Pond 1P: Drop Structure 14 Pond MHC1: Drain in Drive 17 Pond Y1: Yard MH 19 Link 3L: Flow over parking 20 Link 4L: Yard overflow 21 Link Prop: Total Proposed 10-Year Event 22 Node Listing 23 Subcat 1PS: PS1 25 Subcat 2PS: S2 27 Pond 1P: Drop Structure 29 Pond MHC1: Drain in Drive 32 Pond Y1: Yard MH 34 Link 3L: Flow over parking 35 Link 4L: Yard overflow 36 Link Prop: Total Proposed 25-Year Event 37 Node Listing 38 Subcat 1PS: PS1 40 Subcat 2PS: S2 42 Pond 1P: Drop Structure 44 Pond MHC1: Drain in Drive 47 Pond Y1: Yard MH 49 Link 3L: Flow over parking 50 Link 4L: Yard overflow 51 Link Prop: Total Proposed 100-Year Event 52 Node Listing 53 Subcat 1PS: PS1 55 Subcat 2PS: S2 Proposed Table of Contents36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC 57 Pond 1P: Drop Structure 59 Pond MHC1: Drain in Drive 62 Pond Y1: Yard MH 64 Link 3L: Flow over parking 65 Link 4L: Yard overflow 66 Link Prop: Total Proposed Proposed 36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 2HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing Event#Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 1-Year Type III 24-hr Default 24.00 1 2.55 2 2 2-Year Type III 24-hr Default 24.00 1 3.09 2 3 5-Year Type III 24-hr Default 24.00 1 4.11 2 4 10-Year Type III 24-hr Default 24.00 1 4.95 2 5 25-Year Type III 24-hr Default 24.00 1 6.12 2 6 50-Year Type III 24-hr Default 24.00 1 6.97 2 7 100-Year Type III 24-hr Default 24.00 1 7.91 2 Proposed 36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 3HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.195 39 >75% Grass cover, Good, HSG A (1PS, 2PS) 0.084 35 Brush, Fair, HSG A (2PS) 0.237 77 Brush, Fair, HSG D (2PS) 0.017 96 Gravel surface, HSG A (1PS) 0.016 98 Imp Decks (2PS) 0.086 98 Paved parking & Walks, HSG A (1PS) 0.081 98 Paved parking, HSG A (1PS, 2PS) 0.072 98 Unconnected roofs, HSG A (1PS, 2PS) 0.033 98 Unconnected roofs, HSG A Prop Bldg (2PS) 0.821 71 TOTAL AREA Proposed 36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 4HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.568 HSG A 1PS, 2PS 0.000 HSG B 0.000 HSG C 0.237 HSG D 2PS 0.016 Other 2PS 0.821 TOTAL AREA Proposed 36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 5HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.195 0.000 0.000 0.000 0.000 0.195 >75% Grass cover, Good 1PS, 2PS 0.084 0.000 0.000 0.237 0.000 0.321 Brush, Fair 2PS 0.017 0.000 0.000 0.000 0.000 0.017 Gravel surface 1PS 0.000 0.000 0.000 0.000 0.016 0.016 Imp Decks 2PS 0.081 0.000 0.000 0.000 0.000 0.081 Paved parking 1PS, 2PS 0.086 0.000 0.000 0.000 0.000 0.086 Paved parking & Walks 1PS 0.104 0.000 0.000 0.000 0.000 0.104 Unconnected roofs 1PS, 2PS 0.568 0.000 0.000 0.237 0.016 0.821 TOTAL AREA Proposed 36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 6HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line#Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 1P 120.50 119.00 10.0 0.1500 0.010 4.0 0.0 0.0 2 MHC1 132.60 130.00 48.0 0.0542 0.010 6.0 0.0 0.0 3 Y1 129.50 126.50 55.0 0.0545 0.013 6.0 0.0 0.0 Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 7HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=14,079 sf 67.26% Impervious Runoff Depth=1.45"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=0.63 cfs 0.039 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=0.47"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=0.20 cfs 0.020 af Peak Elev=121.06' Storage=7 cf Inflow=0.21 cfs 0.038 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.21 cfs 0.038 af Peak Elev=133.49' Storage=421 cf Inflow=0.63 cfs 0.039 afPond MHC1: Drain in Drive Primary=0.21 cfs 0.038 af Secondary=0.00 cfs 0.000 af Outflow=0.21 cfs 0.038 af Peak Elev=129.78' Storage=3 cf Inflow=0.21 cfs 0.038 afPond Y1: Yard MH Primary=0.21 cfs 0.038 af Secondary=0.00 cfs 0.000 af Outflow=0.21 cfs 0.038 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=0.39 cfs 0.057 afLink Prop: Total Proposed Primary=0.39 cfs 0.057 af Total Runoff Area = 0.821 ac Runoff Volume = 0.059 af Average Runoff Depth = 0.86" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 8HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =0.63 cfs @ 12.03 hrs, Volume=0.039 af, Depth=1.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.09" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 9HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 2-Year Rainfall=3.09" Runoff Area=14,079 sf Runoff Volume=0.039 af Runoff Depth=1.45" Flow Length=170' Tc=2.1 min CN=82 0.63 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 10HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =0.20 cfs @ 12.09 hrs, Volume=0.020 af, Depth=0.47" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.09" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 11HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 2-Year Rainfall=3.09" Runoff Area=21,662 sf Runoff Volume=0.020 af Runoff Depth=0.47" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 0.20 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 12HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 1.40" for 2-Year event Inflow =0.21 cfs @ 12.31 hrs, Volume=0.038 af Outflow =0.21 cfs @ 12.31 hrs, Volume=0.038 af, Atten= 0%, Lag= 0.1 min Primary =0.21 cfs @ 12.31 hrs, Volume=0.038 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 121.06' @ 12.31 hrs Surf.Area= 2 sf Storage= 7 cf Plug-Flow detention time= 2.9 min calculated for 0.038 af (100% of inflow) Center-of-Mass det. time= 0.8 min ( 859.2 - 858.4 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.21 cfs @ 12.31 hrs HW=121.06' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.21 cfs @ 2.40 fps) Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 13HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 Inflow Area=0.323 ac Peak Elev=121.06' Storage=7 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.21 cfs 0.21 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 14HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 1.45" for 2-Year event Inflow =0.63 cfs @ 12.03 hrs, Volume=0.039 af Outflow =0.21 cfs @ 12.31 hrs, Volume=0.038 af, Atten= 67%, Lag= 16.6 min Primary =0.21 cfs @ 12.31 hrs, Volume=0.038 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 133.49' @ 12.31 hrs Surf.Area= 1,249 sf Storage= 421 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 43.1 min calculated for 0.038 af (97% of inflow) Center-of-Mass det. time= 23.7 min ( 858.0 - 834.4 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.21 cfs @ 12.31 hrs HW=133.49' TW=129.78' (Dynamic Tailwater) 1=Culvert (Passes 0.21 cfs of 0.60 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.21 cfs @ 3.99 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 15HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 16HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 Inflow Area=0.323 ac Peak Elev=133.49' Storage=421 cf 0.63 cfs 0.21 cfs 0.21 cfs 0.00 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 17HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 1.40" for 2-Year event Inflow =0.21 cfs @ 12.31 hrs, Volume=0.038 af Outflow =0.21 cfs @ 12.31 hrs, Volume=0.038 af, Atten= 0%, Lag= 0.1 min Primary =0.21 cfs @ 12.31 hrs, Volume=0.038 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 129.78' @ 12.31 hrs Surf.Area= 4 sf Storage= 3 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 1.2 min calculated for 0.038 af (100% of inflow) Center-of-Mass det. time= 0.4 min ( 858.4 - 858.0 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.21 cfs @ 12.31 hrs HW=129.78' TW=121.06' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.21 cfs @ 1.82 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 18HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 Inflow Area=0.323 ac Peak Elev=129.78' Storage=3 cf 0.21 cfs 0.21 cfs 0.21 cfs 0.00 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 19HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 20HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 2-Year Rainfall=3.09"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 21HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 0.83" for 2-Year event Inflow =0.39 cfs @ 12.10 hrs, Volume=0.057 af Primary =0.39 cfs @ 12.10 hrs, Volume=0.057 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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=0.821 ac 0.39 cfs 0.39 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 22HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=14,079 sf 67.26% Impervious Runoff Depth=3.03"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=1.32 cfs 0.082 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=1.48"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=0.86 cfs 0.061 af Peak Elev=121.53' Storage=8 cf Inflow=0.31 cfs 0.080 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.31 cfs 0.080 af Peak Elev=134.27' Storage=1,040 cf Inflow=1.32 cfs 0.082 afPond MHC1: Drain in Drive Primary=0.31 cfs 0.080 af Secondary=0.00 cfs 0.000 af Outflow=0.31 cfs 0.080 af Peak Elev=129.86' Storage=3 cf Inflow=0.31 cfs 0.080 afPond Y1: Yard MH Primary=0.31 cfs 0.080 af Secondary=0.00 cfs 0.000 af Outflow=0.31 cfs 0.080 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=1.14 cfs 0.141 afLink Prop: Total Proposed Primary=1.14 cfs 0.141 af Total Runoff Area = 0.821 ac Runoff Volume = 0.143 af Average Runoff Depth = 2.09" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 23HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =1.32 cfs @ 12.03 hrs, Volume=0.082 af, Depth=3.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 24HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 10-Year Rainfall=4.95" Runoff Area=14,079 sf Runoff Volume=0.082 af Runoff Depth=3.03" Flow Length=170' Tc=2.1 min CN=82 1.32 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 25HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =0.86 cfs @ 12.07 hrs, Volume=0.061 af, Depth=1.48" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.95" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 26HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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 10-Year Rainfall=4.95" Runoff Area=21,662 sf Runoff Volume=0.061 af Runoff Depth=1.48" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 0.86 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 27HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 2.98" for 10-Year event Inflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af Outflow =0.31 cfs @ 12.41 hrs, Volume=0.080 af, Atten= 0%, Lag= 0.2 min Primary =0.31 cfs @ 12.41 hrs, Volume=0.080 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 121.53' @ 12.41 hrs Surf.Area= 2 sf Storage= 8 cf Plug-Flow detention time= 1.6 min calculated for 0.080 af (100% of inflow) Center-of-Mass det. time= 0.6 min ( 846.5 - 845.9 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.31 cfs @ 12.41 hrs HW=121.53' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.31 cfs @ 3.53 fps) Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 28HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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=0.323 ac Peak Elev=121.53' Storage=8 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.31 cfs 0.31 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 29HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 3.03" for 10-Year event Inflow =1.32 cfs @ 12.03 hrs, Volume=0.082 af Outflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af, Atten= 77%, Lag= 22.2 min Primary =0.31 cfs @ 12.40 hrs, Volume=0.080 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 134.27' @ 12.40 hrs Surf.Area= 1,249 sf Storage= 1,040 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 42.6 min calculated for 0.080 af (98% of inflow) Center-of-Mass det. time= 32.6 min ( 845.6 - 813.1 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.31 cfs @ 12.40 hrs HW=134.27' TW=129.86' (Dynamic Tailwater) 1=Culvert (Passes 0.31 cfs of 0.89 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.31 cfs @ 5.87 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 30HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 31HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.323 ac Peak Elev=134.27' Storage=1,040 cf 1.32 cfs 0.31 cfs 0.31 cfs 0.00 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 32HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 2.98" for 10-Year event Inflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af Outflow =0.31 cfs @ 12.40 hrs, Volume=0.080 af, Atten= 0%, Lag= 0.0 min Primary =0.31 cfs @ 12.40 hrs, Volume=0.080 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 129.86' @ 12.40 hrs Surf.Area= 4 sf Storage= 3 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 0.7 min calculated for 0.080 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 845.9 - 845.6 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.31 cfs @ 12.40 hrs HW=129.86' TW=121.53' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.31 cfs @ 2.04 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 33HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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=0.323 ac Peak Elev=129.86' Storage=3 cf 0.31 cfs 0.31 cfs 0.31 cfs 0.00 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 34HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 35HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 10-Year Rainfall=4.95"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 36HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 2.07" for 10-Year event Inflow =1.14 cfs @ 12.07 hrs, Volume=0.141 af Primary =1.14 cfs @ 12.07 hrs, Volume=0.141 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.821 ac 1.14 cfs 1.14 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 37HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=14,079 sf 67.26% Impervious Runoff Depth=4.10"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=1.77 cfs 0.110 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=2.26"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=1.37 cfs 0.094 af Peak Elev=121.83' Storage=9 cf Inflow=0.36 cfs 0.109 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.36 cfs 0.109 af Peak Elev=134.78' Storage=1,504 cf Inflow=1.77 cfs 0.110 afPond MHC1: Drain in Drive Primary=0.36 cfs 0.109 af Secondary=0.00 cfs 0.000 af Outflow=0.36 cfs 0.109 af Peak Elev=129.90' Storage=4 cf Inflow=0.36 cfs 0.109 afPond Y1: Yard MH Primary=0.36 cfs 0.109 af Secondary=0.00 cfs 0.000 af Outflow=0.36 cfs 0.109 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=1.68 cfs 0.203 afLink Prop: Total Proposed Primary=1.68 cfs 0.203 af Total Runoff Area = 0.821 ac Runoff Volume = 0.204 af Average Runoff Depth = 2.98" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 38HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =1.77 cfs @ 12.03 hrs, Volume=0.110 af, Depth=4.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.12" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 39HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 25-Year Rainfall=6.12" Runoff Area=14,079 sf Runoff Volume=0.110 af Runoff Depth=4.10" Flow Length=170' Tc=2.1 min CN=82 1.77 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 40HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =1.37 cfs @ 12.07 hrs, Volume=0.094 af, Depth=2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 25-Year Rainfall=6.12" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 41HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 25-Year Rainfall=6.12" Runoff Area=21,662 sf Runoff Volume=0.094 af Runoff Depth=2.26" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 1.37 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 42HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 4.05" for 25-Year event Inflow =0.36 cfs @ 12.43 hrs, Volume=0.109 af Outflow =0.36 cfs @ 12.44 hrs, Volume=0.109 af, Atten= 0%, Lag= 0.2 min Primary =0.36 cfs @ 12.44 hrs, Volume=0.109 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 121.83' @ 12.44 hrs Surf.Area= 2 sf Storage= 9 cf Plug-Flow detention time= 1.3 min calculated for 0.109 af (100% of inflow) Center-of-Mass det. time= 0.5 min ( 844.8 - 844.2 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.36 cfs @ 12.44 hrs HW=121.83' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.36 cfs @ 4.10 fps) Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 43HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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=0.323 ac Peak Elev=121.83' Storage=9 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.36 cfs 0.36 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 44HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 4.10" for 25-Year event Inflow =1.77 cfs @ 12.03 hrs, Volume=0.110 af Outflow =0.36 cfs @ 12.43 hrs, Volume=0.109 af, Atten= 80%, Lag= 24.0 min Primary =0.36 cfs @ 12.43 hrs, Volume=0.109 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 134.78' @ 12.43 hrs Surf.Area= 1,249 sf Storage= 1,504 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 47.1 min calculated for 0.109 af (99% of inflow) Center-of-Mass det. time= 39.4 min ( 844.0 - 804.5 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.36 cfs @ 12.43 hrs HW=134.78' TW=129.90' (Dynamic Tailwater) 1=Culvert (Passes 0.36 cfs of 1.04 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.36 cfs @ 6.83 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 45HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 46HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.323 ac Peak Elev=134.78' Storage=1,504 cf 1.77 cfs 0.36 cfs 0.36 cfs 0.00 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 47HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 4.05" for 25-Year event Inflow =0.36 cfs @ 12.43 hrs, Volume=0.109 af Outflow =0.36 cfs @ 12.43 hrs, Volume=0.109 af, Atten= 0%, Lag= 0.1 min Primary =0.36 cfs @ 12.43 hrs, Volume=0.109 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 129.90' @ 12.43 hrs Surf.Area= 4 sf Storage= 4 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 0.5 min calculated for 0.109 af (100% of inflow) Center-of-Mass det. time= 0.3 min ( 844.2 - 844.0 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.36 cfs @ 12.43 hrs HW=129.90' TW=121.83' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.36 cfs @ 2.14 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 48HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)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=0.323 ac Peak Elev=129.90' Storage=4 cf 0.36 cfs 0.36 cfs 0.36 cfs 0.00 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 49HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 50HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 25-Year Rainfall=6.12"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 51HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 2.96" for 25-Year event Inflow =1.68 cfs @ 12.07 hrs, Volume=0.203 af Primary =1.68 cfs @ 12.07 hrs, Volume=0.203 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.821 ac 1.68 cfs 1.68 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 52HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Time span=0.00-38.00 hrs, dt=0.01 hrs, 3801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Runoff Area=14,079 sf 67.26% Impervious Runoff Depth=5.77"Subcatchment 1PS: PS1 Flow Length=170' Tc=2.1 min CN=82 Runoff=2.46 cfs 0.156 af Runoff Area=21,662 sf 14.06% Impervious Runoff Depth=3.60"Subcatchment 2PS: S2 Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 Runoff=2.24 cfs 0.149 af Peak Elev=123.64' Storage=12 cf Inflow=0.57 cfs 0.154 afPond 1P: Drop Structure 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' Outflow=0.57 cfs 0.154 af Peak Elev=137.81' Storage=2,192 cf Inflow=2.46 cfs 0.156 afPond MHC1: Drain in Drive Primary=0.57 cfs 0.154 af Secondary=0.00 cfs 0.000 af Outflow=0.57 cfs 0.154 af Peak Elev=130.12' Storage=4 cf Inflow=0.57 cfs 0.154 afPond Y1: Yard MH Primary=0.57 cfs 0.154 af Secondary=0.00 cfs 0.000 af Outflow=0.57 cfs 0.154 af Inflow=0.00 cfs 0.000 afLink 3L: Flow over parking Primary=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afLink 4L: Yard overflow Primary=0.00 cfs 0.000 af Inflow=2.60 cfs 0.303 afLink Prop: Total Proposed Primary=2.60 cfs 0.303 af Total Runoff Area = 0.821 ac Runoff Volume = 0.305 af Average Runoff Depth = 4.46" 64.98% Pervious = 0.533 ac 35.02% Impervious = 0.287 ac Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 53HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 1PS: PS1 Runoff =2.46 cfs @ 12.03 hrs, Volume=0.156 af, Depth=5.77" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Description 3,853 39 >75% Grass cover, Good, HSG A 1,420 98 Unconnected roofs, HSG A 967 98 Unconnected roofs, HSG A *3,735 98 Paved parking & Walks, HSG A *3,348 98 Paved parking, HSG A 756 96 Gravel surface, HSG A 14,079 82 Weighted Average 4,609 32.74% Pervious Area 9,470 67.26% Impervious Area 2,387 25.21% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 1.5 80 0.0250 0.86 Sheet Flow, gar - drain n= 0.020 P2= 3.00" 0.6 90 0.0174 2.68 Shallow Concentrated Flow, gar - drain2 Paved Kv= 20.3 fps 2.1 170 Total Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 54HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 1PS: PS1 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=14,079 sf Runoff Volume=0.156 af Runoff Depth=5.77" Flow Length=170' Tc=2.1 min CN=82 2.46 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 55HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment 2PS: S2 Runoff =2.24 cfs @ 12.06 hrs, Volume=0.149 af, Depth=3.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=7.91" Area (sf)CN Adj Description *1,420 98 Unconnected roofs, HSG A Prop Bldg 733 98 Unconnected roofs, HSG A 4,633 39 >75% Grass cover, Good, HSG A 3,672 35 Brush, Fair, HSG A 10,311 77 Brush, Fair, HSG D 186 98 Paved parking, HSG A *707 98 Imp Decks 21,662 65 63 Weighted Average, UI Adjusted 18,616 85.94% Pervious Area 3,046 14.06% Impervious Area 2,153 70.68% Unconnected Tc Length Slope Velocity Capacity Description (min)(feet)(ft/ft)(ft/sec)(cfs) 2.8 42 0.2200 0.25 Sheet Flow, Gar to Brush Grass: Dense n= 0.240 P2= 3.00" 1.2 86 0.2200 1.17 Shallow Concentrated Flow, Brush to Botom Forest w/Heavy Litter Kv= 2.5 fps 4.0 128 Total Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 56HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Subcatchment 2PS: S2 Runoff Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Type III 24-hr 100-Year Rainfall=7.91" Runoff Area=21,662 sf Runoff Volume=0.149 af Runoff Depth=3.60" Flow Length=128' Slope=0.2200 '/' Tc=4.0 min UI Adjusted CN=63 2.24 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 57HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond 1P: Drop Structure Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.72" for 100-Year event Inflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af Outflow =0.57 cfs @ 12.40 hrs, Volume=0.154 af, Atten= 0%, Lag= 0.4 min Primary =0.57 cfs @ 12.40 hrs, Volume=0.154 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 123.64' @ 12.40 hrs Surf.Area= 2 sf Storage= 12 cf Plug-Flow detention time= 1.0 min calculated for 0.154 af (100% of inflow) Center-of-Mass det. time= 0.5 min ( 842.5 - 842.0 ) Volume Invert Avail.Storage Storage Description #1 117.50'28 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 117.50 2 0 0 131.50 2 28 28 Device Routing Invert Outlet Devices #1 Primary 120.50'4.0" Round Culvert L= 10.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 120.50' / 119.00' S= 0.1500 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.09 sf Primary OutFlow Max=0.57 cfs @ 12.40 hrs HW=123.64' TW=0.00' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 6.56 fps) Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 58HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond 1P: Drop Structure Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.323 ac Peak Elev=123.64' Storage=12 cf 4.0" Round Culvert n=0.010 L=10.0' S=0.1500 '/' 0.57 cfs 0.57 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 59HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond MHC1: Drain in Drive Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.77" for 100-Year event Inflow =2.46 cfs @ 12.03 hrs, Volume=0.156 af Outflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af, Atten= 77%, Lag= 21.4 min Primary =0.57 cfs @ 12.39 hrs, Volume=0.154 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 137.81' @ 12.39 hrs Surf.Area= 1,582 sf Storage= 2,192 cf Flood Elev= 138.01' Surf.Area= 2,729 sf Storage= 2,371 cf Plug-Flow detention time= 52.5 min calculated for 0.154 af (99% of inflow) Center-of-Mass det. time= 46.9 min ( 841.8 - 794.9 ) Volume Invert Avail.Storage Storage Description #1A 132.79'1,144 cf 14.50'W x 84.75'L x 3.04'H Field A 3,738 cf Overall - 877 cf Embedded = 2,861 cf x 40.0% Voids #2A 133.79'877 cf Cultec R-150XLHD x 32 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows #3 129.75'350 cf Manhole (Prismatic) Listed below (Recalc) 2,371 cf Total Available Storage Storage Group A created with Chamber Wizard Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.75 20 0 0 137.75 20 160 160 138.00 1,500 190 350 Device Routing Invert Outlet Devices #1 Primary 132.60'6.0" Round Culvert L= 48.0' CPP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 132.60' / 130.00' S= 0.0542 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #2 Device 1 132.70'3.1" Vert. Orifice 1 C= 0.610 Limited to weir flow at low heads #3 Secondary 137.95'8.0' long (Profile 6) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 Coef. (English) 3.12 3.41 3.59 Primary OutFlow Max=0.57 cfs @ 12.39 hrs HW=137.81' TW=130.12' (Dynamic Tailwater) 1=Culvert (Passes 0.57 cfs of 1.66 cfs potential flow) 2=Orifice 1 (Orifice Controls 0.57 cfs @ 10.92 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.75' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 60HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive - Chamber Wizard Field A Chamber Model = Cultec R-150XLHD (Cultec Recharger® 150XLHD) Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 4 rows 33.0" Wide + 6.0" Spacing = 39.0" C-C Row Spacing 8 Chambers/Row x 10.25' Long +0.75' Row Adjustment = 82.75' Row Length +12.0" End Stone x 2 = 84.75' Base Length 4 Rows x 33.0" Wide + 6.0" Spacing x 3 + 12.0" Side Stone x 2 = 14.50' Base Width 12.0" Stone Base + 18.5" Chamber Height + 6.0" Stone Cover = 3.04' Field Height 32 Chambers x 27.2 cf +0.75' Row Adjustment x 2.65 sf x 4 Rows = 876.8 cf Chamber Storage 3,737.8 cf Field - 876.8 cf Chambers = 2,861.0 cf Stone x 40.0% Voids = 1,144.4 cf Stone Storage Chamber Storage + Stone Storage = 2,021.2 cf = 0.046 af Overall Storage Efficiency = 54.1% Overall System Size = 84.75' x 14.50' x 3.04' 32 Chambers 138.4 cy Field 106.0 cy Stone 1 Membrane Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 61HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond MHC1: Drain in Drive Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.323 ac Peak Elev=137.81' Storage=2,192 cf 2.46 cfs 0.57 cfs 0.57 cfs 0.00 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 62HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Pond Y1: Yard MH Inflow Area =0.323 ac,67.26% Impervious, Inflow Depth = 5.72" for 100-Year event Inflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af Outflow =0.57 cfs @ 12.39 hrs, Volume=0.154 af, Atten= 0%, Lag= 0.1 min Primary =0.57 cfs @ 12.39 hrs, Volume=0.154 af Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Peak Elev= 130.12' @ 12.39 hrs Surf.Area= 4 sf Storage= 4 cf Flood Elev= 133.00' Surf.Area= 4 sf Storage= 14 cf Plug-Flow detention time= 0.4 min calculated for 0.154 af (100% of inflow) Center-of-Mass det. time= 0.2 min ( 842.0 - 841.8 ) Volume Invert Avail.Storage Storage Description #1 129.00'14 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet)(sq-ft)(cubic-feet)(cubic-feet) 129.00 4 0 0 132.50 4 14 14 Device Routing Invert Outlet Devices #1 Primary 129.50'6.0" Round Culvert L= 55.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 129.50' / 126.50' S= 0.0545 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.20 sf #2 Secondary 132.25'8.0' long Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 1.48 1.97 2.46 2.95 3.94 Coef. (English) 2.61 2.64 2.81 2.83 3.06 3.19 3.33 Primary OutFlow Max=0.57 cfs @ 12.39 hrs HW=130.12' TW=123.64' (Dynamic Tailwater) 1=Culvert (Inlet Controls 0.57 cfs @ 2.92 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 63HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Pond Y1: Yard MH Inflow Outflow Primary Secondary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.323 ac Peak Elev=130.12' Storage=4 cf 0.57 cfs 0.57 cfs 0.57 cfs 0.00 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 64HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 3L: Flow over parking Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 3L: Flow over parking Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 65HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link 4L: Yard overflow Inflow =0.00 cfs @ 0.00 hrs, Volume=0.000 af Primary =0.00 cfs @ 0.00 hrs, Volume=0.000 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link 4L: Yard overflow Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)1 0 0.00 cfs 0.00 cfs Proposed Type III 24-hr 100-Year Rainfall=7.91"36 Hampden Noho Proposed 8-31-2020 Printed 9/14/2020Prepared by The Engineer Group, LLC Page 66HydroCAD® 10.10-3a s/n 11174 © 2020 HydroCAD Software Solutions LLC Summary for Link Prop: Total Proposed Inflow Area =0.821 ac,35.02% Impervious, Inflow Depth = 4.43" for 100-Year event Inflow =2.60 cfs @ 12.06 hrs, Volume=0.303 af Primary =2.60 cfs @ 12.06 hrs, Volume=0.303 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-38.00 hrs, dt= 0.01 hrs Link Prop: Total Proposed Inflow Primary Hydrograph Time (hours) 38373635343332313029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.821 ac 2.60 cfs 2.60 cfs The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX B Standard 3 Recharge Supporting Information Drawing Showing insufficient room on site to locate recharge practice due to Setback Requirements 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX C Standard 4 Water Quality Calculations, Cultec ISO and TSS Removal Form 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report Water Quality Volume for Proprietary Systems Required WQ volume = post total impervious area: (Paving, walks, roofs) = 3921+1265+1574+2(119)+ 469 = 7467sf Total VWQ 0.5" = 7467sf (0.5") (1ft/12") = 311 CF = 0.007 Af 3921 sf Tot Prop. Imp. Parking Walkways on site = 0.0001406 sm Tc = 2.1m = 0.35h qu, Ia/P, 0.58 =820 csm/in Q 0.5 =qu (A)(0.5") =0.0576cfs Check using Hydrocad cutting time of 100 yr storm at 0.007 Af ; WQ0.5" = 0.06 cfs = 27 g/min Using Cultec Separator Row Flow Efficiency Charts 48gpm = 76.9% 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX D Standard 8 CPPP and ES Plan See Full Size Plan and Notes on Page 4 of 5 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report APPENDIX E Standard 9 Operation Maintenance Plan and Cultec Separator Row 5-30-2020 Pioneer Development, LLC 32 Perkins Ave Stormwater Management System Operation and Maintenance Plan (O&M) and Long Term Pollution Prevention Plan (LTPPP) This Stormwater Management System Operation and Maintenance Plan provides for the inspection and maintenance of structural Best Management Practices (BMPs) and for measures to prevent pollution associated with the Proposed Multi Family Housing Project located at 36 Hampden St, Northampton, MA. This document has been prepared in accordance with the requirements of the Stormwater Regulations included in the Massachusetts Wetlands Protection Act Regulations (310 CMR 10). Stormwater Management System Owner: Pioneer Development, LLC 32 Perkins Ave Northampton, MA 413-320-7208 A complete and thorough inspection of the stormwater management system shall be performed once a month during the first six months of operation and then as prescribed below. The Inspection and Maintenance Forms provided in Attachments A and B shall be prepared by qualified personnel. The stormwater management system will be maintained properly to assure its continued performance, as follows. 1. Catch basins and area drains a. Inspect quarterly for the first year (January, April, July, October), then semi annually, (April, October after leaf fall) thereafter, and after any storm greater than 3”. Clean if sediment accumulation has reached 18” depth. b. Sumps should be cleaned of sediment a minimum of once per year. 2. Cultec Separator Row Chambers, follow manufacturer’s recommendations (see Attachment B) including at a minimum: a. Inspect twice a year (spring and fall) minimum. One of the inspections should occur after a storm event greater than or equal to one inch in a 24-hour period, occurring within 8 hours following the cessation of the storm as reasonably practicable. b. Jet and Pump once per year to remove oils and sediment from catch basin, and isolator chamber row. If Engineer inspection shows a lesser frequency may be used then this document shall be revised and copies to all parties involved, including the Municipality. c. Confirm system components are in working order and there are no obstructions in the inlet or Drain Basin or in the overflow Hood. d. Measure depth to sediment/pollutant accumulation with a sediment probe, tape measure, or other measuring device. System should be cleaned when the level of sediment has reached the depth specified in the manufacturers literature or once per year, whichever is sooner. See (b) above for frequency revision. e. Remove floatable trash, debris and oil in accordance with the Catch Basin and Drains Section above. f. Cleaning should be done during dry weather. A vacuum truck and Jet is the recommended method of removing pollutants from the system (see O&M manual attached). Insert vacuum hose into the sump and jet the isolator row back into the drain basin. The system should be completely drained down and the sump fully evacuated of sediment and debris. 3. Outlet Control Structures ( man hole near the Bike Rack) a. Inspect quarterly (January, April, July, October) first year, twice per year thereafter, (April, October) . 4. Driveway and Parking Lots a. Driveway and parking lot shall be cleaned with vacuum sweepers, leaf blowers, or other means twice per year (generally May and November). b. Material shall be removed from the pavement by landscaping crews using leaf blowers or sweeping during the growing season, immediately following each lawn trimming. The lot should be swept or vacuumed of sand debris every spring (April). See 3. below for lawn trimming frequency. c. Curbing, guard rails, and parking stops shall be inspected and repaired each spring as necessary. d. Any grass creeping over the curbing shall be edged back, and sediment deposits built up higher than the the curb shall be removed flush to the curb, and lawn re- seeded immediately as necessary 5. Building gutters a. Cleaned twice annually (typically during the spring and after the fall foliage has dropped from the trees). Alternatively, gutter guard screens may be installed. b. Rain Barrels shall be emptied into the planting areas after each rain event so they are able to capture the next storm. c. Rain barrel screens, valves and components to be inspected and repaired as needed. See Attachment D Practices for Long Term Pollution Prevention 1. Litter Clean-up The Owner will conduct litter clean-up from the stormwater management facilities in conjunction with routine maintenance activities. 2. Routine Inspection and Maintenance of Stormwater BMPs The Owner will conduct inspection and maintenance of the stormwater management practices in accordance with the guidelines discussed above. 3. Maintenance of Landscaped Areas The Owner shall minimize use of herbicides, pesticides for the maintenance of facilities covered by this plan. Fertilizer use will follow the 330 CMR 31.05 regulations for “Requirements for the Application of Nutrients to Land Not Used for Agricultural Purposes.” If not removed from the site, landscaping waste products such as leaves and grass clippings should be composted in a designated area, no closer than 35-feet from a wetland resource. Such material should not be pushed into wetland areas under any circumstance, at any time. Areas designated as grass shall be mowed to maintain a length between 4” and 6” high. 4. Snow and Ice Management Snow piles shall not be placed over drain inlets or to areas on the site where it could melt and flow into the wetland area. A snow storage plan is provided in Attachment C. `5. The following methods of de-icing or anti-icing shall be acceptable, methods may be combined: a. Use of a sand/salt mix (with or without additives) consisting of not more than 20% salt by weight b. Use of calcium magnesium acetate (CMA) or potassium acetate (KAc), or blends thereof c. Use of rock salt (with or without additives), granular or brine, if placed/spread by a calibrated spreader and spread as light application is necessary to promote melting. 6. Prohibition of Illicit Discharges The DEP Stormwater Management Standards prohibit illicit discharges to the storm water management system. Illicit discharges are discharges that do not entirely consist of stormwater, except for certain specified non-stormwater discharges. Discharges from the following activities are not considered illicit discharges: firefighting, foundation drains, water line flushing, footing drains, landscape irrigation, individual resident car washing, uncontaminated groundwater, flows from riparian habitats and wetlands, potable water sources, dechlorinated water from swimming pools, water used to clean residential buildings without detergents, water used for street washing, air conditioning condensation, Pool water (when applicable) will be dechlorinated and within a pH range of 7.2 to 7.8 prior to discharge to the stormwater system. There are no known or proposed illicit discharges associated with this project. 7. Pet waste Pet waste shall not be left on the property, and should be cleaned up immediately after it is produced, and disposed of properly. 8. Household Trash Household trash shall be placed in the covered trash bin and a refuse collection company shall remove it as the bin gets full, or weekly, whichever comes first. At no time shall trash be placed on the property outside of the enclosed container. Items such as tires, furniture, or other bulky items shall not be stored on the property. Record Keeping An “Inspection and Maintenance Form” shall be filled out for each stormwater management system inspection or when maintenance work is required. A binder shall be kept by the Owner or designated representative that contains all the completed inspection forms. Any photographs and related material shall be kept when required and related to the task. The Owner shall engage, on an annual basis, a Professional Engineer (P.E.) registered in Massachusetts with expertise in stormwater management to review the operation and maintenance records from the previous year. The Engineer shall perform an independent inspection of the stormwater management system to ensure that these Stormwater BMPs are being taken care of in the manner illustrated in this Operation & Maintenance Plan. The P.E. will do an annual summary report that includes their observations, maintenance recommendations, or suggested revisions for the stormwater management system, and plan. All operation and maintenance records shall be retained for at least three (3) years and be provided to the Town of Northampton upon request. Stormwater Operations and Maintenance Agreement 36 Hampden Street, Northampton, Massachusetts By signing this statement, I confirm that Pioneer Development, LLC is responsible for the operation and maintenance of the stormwater management facilities and associated stormwater management features proposed by the Multi Family Housing Project at 36 Hampden St, and has read and understands the requirements of this Operation and Maintenance Plan. Maintenance will be conducted in accordance with this Operation and Maintenance Plan and with the MassDEP Stormwater Policy Manual. This Agreement shall be binding upon Pioneer Development, LLC and its successors and assigns. Written notice of the transfer of all its rights and obligations under this Agreement must be provided to the Town of Northampton by the Owner: Signed By Owner: Pioneer Development LLC Signature: ___________________________________________________________ Print Name:___________________________________________________________ Title: ___________________________________________________________ Attachment A Maintenance and Inspection Forms Inspection and Maintenance Form Stormwater BMP’s Practice/System__Deep Sump Basin at Entrance_ Date_______________ Time_________________ Weather/Temp________/____ Last Precip Date___________ Last Precip:Type___________ Amount (inches)_________ Circle one :N/A = Not Applicable, O= OK, F = Future problems may occur, revisit, M = Maintenance Required, E= Emergency Repair Necessary 1. StormwaterStructuresSediment accumulation >12” depth? No Yes O F M E Depth: _______ in. Evidence of oil/grease accumulation No Yes O F M E Other _________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. Pipes:Broken N/A O F M E Clogged N/A O F M E Submerged Outlet Pipe N/A O F M E Inspector’s Summary / additional comments: __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ ___________ Inspection and Maintenance Form Stormwater BMP’s Practice/System__CULTEC CHAMBERS_ Date_______________ Time_________________ Weather/Temp________/____ Last Precip Date___________ Last Precip:Type___________ Amount (inches)_________ Circle one :N/A = Not Applicable, O= OK, F = Future problems may occur, revisit, M = Maintenance Required, E= Emergency Repair Necessary 1. Chamber Sediment Accumulation at inflow Pipe?No Yes O F M E Depth: _______ in. Chamber Sediment Accumulation at inspection port? No Yes O F M E Depth: _______ in. Evidence of oil/grease accumulation No Yes O F M E Other _________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. Pipes:Broken N/A O F M E Clogged N/A O F M E Submerged Outlet Pipe N/A O F M E 3. Standing Water Depth No Yes Depth: _______ in. 4. Time required to fully drain? Hours____________Minutes_______________________ Inspector’s Summary / additional comments: __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ _____________ Inspection and Maintenance Form Stormwater BMP’s Practice/System__Man Hole / Outlet Control at Bike Rack_ Date_______________ Time_________________ Weather/Temp________/____ Last Precip Date___________ Last Precip:Type___________ Amount (inches)_________ Circle one :N/A = Not Applicable, O= OK, F = Future problems may occur, revisit, M = Maintenance Required, E= Emergency Repair Necessary 1. StormwaterStructuresSediment accumulation ? No Yes O F M E Depth: _______ in. Evidence of oil/grease accumulation No Yes O F M E Other _________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. Pipes:Broken N/A O F M E Clogged N/A O F M E Submerged Outlet Pipe O F M E orifices all clear O F M E Inspector’s Summary / additional comments: __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ ____________________________ Inspection and Maintenance Form Stormwater BMP’s Practice/System__Grate Basin / rear yard Date_______________ Time_________________ Weather/Temp________/____ Last Precip Date___________ Last Precip:Type___________ Amount (inches)_________ Circle one :N/A = Not Applicable, O= OK, F = Future problems may occur, revisit, M = Maintenance Required, E= Emergency Repair Necessary 1. StormwaterStructuresSediment accumulation ? No Yes O F M E Depth: _______ in. Evidence of oil/grease accumulation No Yes O F M E Other _________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. Pipes:Broken N/A O F M E Clogged N/A O F M E Submerged Outlet Pipe O F M E Inspector’s Summary / additional comments: __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ ____________________________ Attachment B Cultec Chamber Maintenance Instructions 1 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 Operation & Maintenance Guide for CULTEC Stormwater Management Systems CULTEC Separator™ Row Water Quality System The Founder of Plastic Chamber Technology www.cultec.com | 1(800) 4-CULTEC | 2 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide Doc ID: CULG046 03-16 March 2016 Published by CULTEC, Inc. P.O. Box 280 878 Federal Road Brookfield, Connecticut 06804 USA www.cultec.com Copyright Notice © 2016 CULTEC, Inc. All rights reserved. Printed in the USA. This document and any accompanying CULTEC products are copyrighted by CULTEC, Inc. Any reproduc- tion and/or distribution without prior written consent from CULTEC, Inc. is strictly prohibited. Disclaimers: The drawings, photographs and illustrations shown in this document are for illustrative purposes only and are not necessarily to scale. Actual designs may vary. CULTEC reserves the right to make design and/or specification changes at any time without notice at CULTEC’s sole discretion. CULTEC is not responsible for typographical errors. Protected by one or more of the following patents: Protected by one or more of the following patents: U.S. Patents 6,129,482; 6,322,288; 6,854,925; 7,226,241; 7,806,627; 8,366,346; 8,425,148; and oth- ers; U.S. Designs D613819; D638,095; D668,318 and others; Canadian Patent 2,591,255 and others; Community Designs 1092191; 1745209; and others. CULTEC, the CULTEC logo, RECHARGER, CONTACTOR, HVLV, PAC, STORMFILTER, STORMGENIE and The Chamber with The Stripe are registered trademarks of CULTEC, Inc. Chamber of Choice, 902, HD, 100, 125, 150, 150XL, 180, 280, 330, 330XL, V8, 902, Field Drain Panel, C-1, C-2, C-3, C-4, EZ-24, Landscape Series are trademarks of CULTEC, Inc. All rights reserved. Contact Information: For general information on our other products and services, please contact our offices within the United States at (800)428-5832, (203)775-4416 ext. 202, or e-mail us at custservice@cultec.com. For technical support, please call (203)775-4416 ext. 203 or e-mail tech@cultec.com. Visit www.cultec.com/downloads.html for Product Downloads and CAD details. 8 oz 30 mil pvc or hdpe liner 8 oz 3 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide Introduction CULTEC’s Separator™ Row is an inexpensive means of removing Total Suspended Solids from the CULTEC chamber system, as well as provid- ing easier access for inspection and maintenance. The Separator Row is designed to capture the First Flush of a rain event and is typically included as part of the “Treatment Train” for water quality. The CULTEC Separator Row is a row of CULTEC Contactor or Recharger Chambers that are sur- rounded on all sides by filter fabric. Two layers of CULTEC No. 66 Woven Geotextile are placed be- tween the clean foundation stone and the chamber feet. The chambers are then completely wrapped with CULTEC No. 410 non-woven geotextile. This configuration is designed to trap any sediment and/or debris that may pass through the upstream water-quality structures and into the chamber system. A manhole is typically located adjacent to the separator row for ease of inspection and main- tenance. This manhole is placed upstream of the system and can include a high-flow bypass pipe to pass peak-flows onto adjacent rows of chambers. The upstream manhole is designed with a sump to trap heavier sediment and allow for proper clean- ing of the Separator Row. A JetVac process with a high pressure water nozzle is introduced down the Separator Row via the access manhole to clean all sediment and debris from the Separator Row. Captured pollutants are flushed into the sumped access manhole for vacuuming, and the process is repeated until the Separator Row is completely free of sediment and debris. 4 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide There is no single design to achieve a high level of water quality. The CULTEC Separator Row should be designed as part of an overall best manage- ment practices water quality system. Pre-treat- ment devices such as sump catch basins, inlet baffles and proprietary oil-grit separators and filter systems can all be incorporated upstream of the CULTEC Separator Row. Sumped access/ diversion manholes should be installed directly upstream of the Separator Row. The following is a list of recommended design practices to ensure proper maintenance for the life of the system: • Install sumped access/diversion manholes, including a minimum 24” (600 mm) sump, directly upstream of the Separator Row. • Include a high-flow bypass pipe to divert peak flows that exceed the capacity of the Separator Row to adjacent rows. • Connect the access manhole to the Sepa- rator Row with the largest diameter pipe allowable based on the CULTEC chamber model used. • Maintain a minimum distance between the access manhole and the Separator Row to promote efficient maintenance. • Include at least one inspection port per Separator Row for periodic inspection. Note: Typical JetVac maintenance reels have a maximum of 400 feet (121.9 m) of available hose. Consider this when designing the length of the CULTEC Separator Rows. Design 5 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide Table SR/3.0 Description Contactor 100HD Recharger 150XLHD Recharger 280HD Recharger 330XLHD Recharger 902HD A Min. depth of stone base 6” 152 mm 6” 152 mm 6” 152 mm 6” 152 mm 9” 229 m B Chamber height 12.5” 318 mm 18.5” 470 mm 26.5” 673 mm 30.5” 775 mm 48” 1219 mm C Min. depth of stone required above units for traffic applications 6” 152 mm 6” 152 mm 6” 152 mm 6” 152 mm 12” 305 mm D Min. depth required of 95% com- pacted fill for paved traffic application 8” 203 mm 8” 203 mm 8” 203 mm 10” 254 mm 12” 3305 mm E Max. depth of cover allowed above crown of chamber 12’ 3.65 m 12’ 3.65 m 12’ 3.65 m 12’ 3.65 m 8.5’ 2.59 m Max. allowable pipe size into chamber end wall/end cap 10” 250 mm 12” 300 mm 18” 450 mm 24” 600 mm 24” 600 mm 6 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide CULTEC recommends inspection of the Separa- tor Row to be performed every six months for the first year of service. Future inspection frequency can be adjusted based upon previous inspection observations. However annual inspections are rec- ommended. Inspection of the Separator Row can be achieved via an inspection port riser installed during construction. This inspection port riser will connect the top of the Separator Row chambers to finished grade with a removable lid. Alterna- tively the Separator Row may be inspected via the manhole(s) located at the end(s) of the Separator Row. However this method of inspection requires confined space entry. If entry into the manhole is required, all local and OSHA rules for confined space entries must be strictly followed. To inspect: • Remove the inspection port lid from the floor box frame. • Remove the riser pipe cap. • With a flashlight and stadia rod, measure the depth of sediment. • Record results in a maintenance log. • When depth of sediment exceeds 3” (76 mm), use the JetVac procedure described below. The JetVac process utilizes a high pressure water nozzle controlled from the surface. The high pressure nozzle is introduced down the Separator Row via the access manhole(s). The high pres- sure water cleans all sediment and debris from the Separator Row as the nozzle is retrieved. Captured pollutants are flushed into the sumped access manhole for vacuuming. This process is repeated until the Separator Row is completely free of sediment and debris. A small diameter culvert cleaning nozzle is recommended for this procedure. Inspection and Maintenance High pressure water nozzle Cleaning Separator Row and pipes with high pressure water nozzle SEPARATOR ROW: Separator Row prior to cleaning ADJACENT ROW: When the Separator Row is working properly, the adjacent rows will not show signs of sediment. 7 For more information, contact CULTEC at (203) 775-4416 or visit www.cultec.com. © CULTEC, Inc., March 2016 CULTEC Separator Row Operation & Maintenance Guide CULG046 03-16 CULTEC Separator Row™ Operation & Maintenance Guide DateMode of AccessFrequencyDepth of SedimentActionsExpensesInspectorNotesEx. Inspection PortSemi-annually2”Measure sediment depth with stadia rod. Visually inspect$100DPGDepth of Sediment was mea-sured via Northeast Inspec-tion Port Adjacent to MH-1. Sediment depth was found to be 2”. No further action required at this time.Ex.Access ManholeAnnuallyInspection and Maintenance Record The Founder of Plastic Chamber Technology www.cultec.com | 1(800) 4-CULTEC | 878 Federal Road | P.O. Box 280 | Brookfield , CT 06804 USA CULG046 03-16 Attachment C Snow Storage Area Plan See Page 2 of 5 in Full Size plans Attachment D Rain Barrel Components February 2010 Revision 03 FLAT-BACK RAIN BARREL INSTRUCTIONS PAGE 1/1RTS Companies Inc. | 1027 Industrial Place, P.O. Box 179, St. Clements, Ontario N0B 2M0 | 1-800-663-2803 RTS Companies US Inc. | 2900 Industrial Park Drive, P.O. Box 183, Austinburg, Ohio 44010 | 1-440-275-3077 Spigot Assembly Installation du robinet Screen Installation Installation de l’écran protecteur Screw spigot (end with hexagonal feature) into pre- threaded opening in front of the Flat Back Rain Barrel. Thread spigot until the hex face touches the barrel. Do not over tighten beyond the point where another turn is not possible. Adjust spigot until vertical relative to the barrel. 1.1 1.2 1.3 1.1 1.2 1.3 Visser le robinet (le côté avec le butoir hexagonal) dans le trou fi leté au bas du baril. Continuer à fi leter le robinet jusqu’à ce que le butoir s’emboîte parfaitement à la surface plate. Ne pas trop serrer. Ajuster le robinet jusqu’à ce qu’il soit vertical relativement au baril. Localiser l’écran et insérer dans la section encastrée du baril. Appuyer fermement sur le cadre de l’écran pour verrouiller l’écran au baril. NOTE: If you plan to leave your Rain Barrel outside over the winter it is very important to winterize your Flat-Back Rain Barrel as follows: a) Drain your Rain Barrel. b) Remove the screen and place inside the Rain Barrel. c) Turn the Rain Barrel upside down and set in desired location, preferably in a garage or basement. Failure to comply with these winterization instructions may result in a voided warranty. Standard RTS Companies Inc. Terms & Conditions apply. NOTE : Si vous planifi ez de laisser votre Baril à l’extérieur pendant l’hiver, il est très important de l’aménager pour l’hiver. La garantie sera nul si cette procédure n’est pas suivie : a) Vider votre baril b) Enlever l’écran protecteur et le placer à l’intérieur du baril c) Tourner le baril à l’envers et placer à l’endroit désiré, de préférence. Termes et Conditions de RTS Companies Inc s’appliquent. Locate the screen and press/fi t into recessed section on top of the Flat-Back Rain Barrel. Press down fi rmly onto the screen to secure screen to barrel. 2.1 2.2 2.1 2.2 RTS Home Accents 1027 Industrial Place, | St. Clements, ON | N0B 2M0 t. 800.663.2803 | 519.699.0022 | f. 519.699.0027 | www.rtshomeaccents.com Embrace nature’s solution to our emerging water shortage and explore all the opportunities that fresh, soft, and free rainwater has to offer! Rain Barrel Our authentic oak barrel texture is molded into each barrel and will not fade, rot or risk insect infestation. The RTS Rain Barrel has many unique features including: a flat back to sit flush against a wall, linkable to other rain barrels for increased capacity, screen to keep out debris and insects, and a shut off valve for hose hook-up with dual overflow! Optional barrel stands create a larger offset between the spigot and the ground, making it easier to fill watering cans and for general use. Rain Barrel 5510-000900-56-XX (Brown) 5510-000900-54-XX (Oak) 5510-000900-42-XX (Green) 5510-000600-56-XX (Woodgrain - shown) 5510-000650-56-XX (Woodgrain Dual Spigot) Specifications Length: 24” (609.6 mm) Width: 19” (482.6mm) Height: 34” (863.6 mm) Volume: 50 US Gal. (189 L) Rain Barrel Stand 5510-00021T-80-xx Rain Barrel Link Kit 5510-000138-00-XX (12” pc of 1” clear hose w/ clip) The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report FIGURE 1 Site Locus 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report FIGURE 2 Survey 5-30-2020 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report FIGURE 3 SCS Soils Map and Report 5-30-2020 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Hampshire County, Massachusetts, Central Part 36 Hampden Street, Northampton, MA Natural Resources Conservation Service November 10, 2019 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................12 Map Unit Descriptions........................................................................................12 Hampshire County, Massachusetts, Central Part...........................................14 1—Water.....................................................................................................14 52A—Freetown muck, central lowland, 0 to 1 percent slopes....................14 745C—Hinckley-Merrimac-Urban land complex, 3 to 15 percent slopes....15 References............................................................................................................19 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 468641046864304686450468647046864904686510468653046865504686570468641046864304686450468647046864904686510468653046865504686570694490 694510 694530 694550 694570 694590 694610 694490 694510 694530 694550 694570 694590 694610 42° 18' 25'' N 72° 38' 25'' W42° 18' 25'' N72° 38' 19'' W42° 18' 20'' N 72° 38' 25'' W42° 18' 20'' N 72° 38' 19'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 40 80 160 240 Feet 0 10 20 40 60 Meters Map Scale: 1:886 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 Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:15,800. 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: Hampshire County, Massachusetts, Central Part Survey Area Data: Version 14, Sep 13, 2019 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 29, 2013—Oct 16, 2016 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Custom Soil Resource Report 10 MAP LEGEND MAP INFORMATION imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 11 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 1 Water 0.0 0.0% 52A Freetown muck, central lowland, 0 to 1 percent slopes 0.5 27.0% 745C Hinckley-Merrimac-Urban land complex, 3 to 15 percent slopes 1.4 73.0% Totals for Area of Interest 1.9 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or Custom Soil Resource Report 12 landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 13 Hampshire County, Massachusetts, Central Part 1—Water Map Unit Setting National map unit symbol: 9b24 Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 120 to 200 days Farmland classification: Not prime farmland Map Unit Composition Water: 100 percent Estimates are based on observations, descriptions, and transects of the mapunit. 52A—Freetown muck, central lowland, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2t2qf Elevation: 90 to 580 feet Mean annual precipitation: 36 to 53 inches Mean annual air temperature: 41 to 54 degrees F Frost-free period: 140 to 220 days Farmland classification: Not prime farmland Map Unit Composition Freetown and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Freetown Setting Landform: Swamps, kettles, bogs, depressions, marshes, depressions Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Tread, dip Down-slope shape: Concave Across-slope shape: Concave Parent material: Highly decomposed organic material Typical profile Oe - 0 to 2 inches: mucky peat Oa - 2 to 79 inches: muck Properties and qualities Slope: 0 to 1 percent Percent of area covered with surface fragments: 0.0 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Very poorly drained Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat): Moderately low to high (0.14 to 14.17 in/hr) Custom Soil Resource Report 14 Depth to water table: About 0 to 6 inches Frequency of flooding: Rare Frequency of ponding: Frequent Available water storage in profile: Very high (about 19.2 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 5w Hydrologic Soil Group: B/D Hydric soil rating: Yes Minor Components Whitman Percent of map unit: 5 percent Landform: Drainageways, depressions Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope Down-slope shape: Concave Across-slope shape: Concave Hydric soil rating: Yes Scarboro Percent of map unit: 5 percent Landform: Depressions, drainageways Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope, tread, dip Down-slope shape: Concave Across-slope shape: Concave Hydric soil rating: Yes Swansea Percent of map unit: 5 percent Landform: Marshes, bogs, swamps, kettles, depressions, depressions Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Tread, dip Down-slope shape: Concave Across-slope shape: Concave Hydric soil rating: Yes 745C—Hinckley-Merrimac-Urban land complex, 3 to 15 percent slopes Map Unit Setting National map unit symbol: 2tx0b Elevation: 0 to 410 feet Mean annual precipitation: 36 to 53 inches Mean annual air temperature: 41 to 54 degrees F Frost-free period: 140 to 220 days Farmland classification: Not prime farmland Custom Soil Resource Report 15 Map Unit Composition Hinckley and similar soils: 30 percent Merrimac and similar soils: 25 percent Urban land: 25 percent Minor components: 20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hinckley Setting Landform: Kame terraces, outwash plains, moraines, outwash deltas, outwash terraces, kames, eskers Landform position (two-dimensional): Shoulder, backslope, footslope, toeslope Landform position (three-dimensional): Side slope, crest, nose slope, head slope Down-slope shape: Linear, convex, concave Across-slope shape: Convex, linear, concave Parent material: Sandy and gravelly glaciofluvial deposits derived from gneiss and/or granite and/or schist Typical profile A - 0 to 8 inches: loamy sand Bw1 - 8 to 11 inches: gravelly loamy sand Bw2 - 11 to 16 inches: gravelly loamy sand BC - 16 to 19 inches: very gravelly loamy sand C - 19 to 65 inches: very gravelly sand Properties and qualities Slope: 3 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to very high (1.42 to 99.90 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Salinity, maximum in profile: Nonsaline (0.0 to 1.9 mmhos/cm) Available water storage in profile: Very low (about 2.9 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4e Hydrologic Soil Group: A Hydric soil rating: No Description of Merrimac Setting Landform: Eskers, outwash terraces, moraines, outwash plains, kames Landform position (two-dimensional): Shoulder, backslope, footslope, toeslope Landform position (three-dimensional): Side slope, crest, nose slope, head slope, riser, tread Down-slope shape: Convex Across-slope shape: Convex Custom Soil Resource Report 16 Parent material: Loamy glaciofluvial deposits derived from granite, schist, and gneiss over sandy and gravelly glaciofluvial deposits derived from granite, schist, and gneiss Typical profile Ap - 0 to 10 inches: fine sandy loam Bw1 - 10 to 22 inches: fine sandy loam Bw2 - 22 to 26 inches: stratified gravel to gravelly loamy sand 2C - 26 to 65 inches: stratified gravel to very gravelly sand Properties and qualities Slope: 3 to 15 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to very high (1.42 to 99.90 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum in profile: 2 percent Salinity, maximum in profile: Nonsaline (0.0 to 1.4 mmhos/cm) Sodium adsorption ratio, maximum in profile: 1.0 Available water storage in profile: Low (about 4.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: A Hydric soil rating: No Description of Urban Land Typical profile M - 0 to 10 inches: cemented material Properties and qualities Slope: 0 to 8 percent Depth to restrictive feature: 0 inches to manufactured layer Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat): Very low (0.00 to 0.00 in/hr) Available water storage in profile: Very low (about 0.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Hydrologic Soil Group: D Hydric soil rating: Unranked Minor Components Sudbury Percent of map unit: 10 percent Landform: Terraces, deltas, outwash plains Landform position (two-dimensional): Toeslope, backslope, summit, footslope Landform position (three-dimensional): Base slope, tread, dip Down-slope shape: Concave Custom Soil Resource Report 17 Across-slope shape: Linear Hydric soil rating: No Windsor Percent of map unit: 10 percent Landform: Outwash plains, deltas, outwash terraces, dunes Landform position (two-dimensional): Backslope, summit, footslope, toeslope Landform position (three-dimensional): Tread, riser Down-slope shape: Linear, convex Across-slope shape: Linear, convex Hydric soil rating: No Custom Soil Resource Report 18 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 19 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 20 The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report FIGURE 4 Wetland/Flood Plain Boundary Map See Full Size Drawings Pg 1 of 5 5-30-2020 MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 1 1 J. Knot Weed Polygonum cuspidatum Siebold & Zucc 30 Y FACU25 .....OBLY5060Skunk Cabbage Symplocarpus foetidus FACW.810Jewel Weed Impatiens capensis Meerb. FACW.810Garlic Mustard Alliaria petiolata (M. Bieb.) Cavara & Grande FACW.810Sens. Fern Onoclea sensibilis ...1Unknown Shrub ?, Exposed Roots, Wind ThrownY7680Norway Maple Acer platanoides L FACWY2425Silver Maple Acer saccharinum L ..... ..... ..... ..... ..... ..... ..... 3 1 36 Hampden St Northampton 7-15-2019 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Wind thrown trees, exposed roots, and water seep observed. Yes Web Soil Survey, Attached O 0-6 10YR 2/1 10YR 5/1 O Histic 0-6 A Fat Clay 6-12 10YR 5/8 X X Water running over surface, from seep 0 0X X MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 2 1 J. Knot Weed Polygonum cuspidatum Siebold & Zucc 30 .FACU10 .....FACWY2370Canadian Clearweed Pilea pumila (L.) A. Gray FACWY2060Jewel Weed Impatiens capensis Meerb. OBL.1030Buttercup (swamp?) yellw watr buttercup Ranunculus flabellaris FACU.310Canada Goldenrod Solidago canadensis L FACW.1340Grove Bluegrass Poa alsodes A. Gray ?.620Unknown herb FACW.825Skunk Cab Symplocarpus foetidus MA Indicator.1340Sphagnum FACW Exp rootsY3140Black Ash Fraxinus nigra Marshall FACWY3950Silv Maple Acer saccharinum L FACUY3140Black Locust Robinia pseudoacacia L FACWY2525Silver Maple Sap Acer saccharinum L FACU.55Multiflora Rose Rosa Multiflora ..... 5 1 36 Hampden St Northampton 300/ 130/ 7-15-2019 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Wind thrown trees, exposed roots, and water seep observed at toe of slope Yes Web Soil Survey, Attached O 0-6 10YR 3/1 O organic 0-0.5 A Silt Loam 0.5-4 None 4X B Sandy Loam 4-13 10YR 4/1 2 additional pits labeled 2A and 2B were dug moving up the slope. 2A at 2-10" 10YR 4/1 w 5YR 5/6 mottles for 50%, and 2B showed Ahoriz 1/2-2 10YR2/2, Bhoriz 2-20" 10YR4/2 Loamy Sand, no Mottles MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 3 1 J. Knot Weed Polygonum cuspidatum Siebold & Zucc 60 Y FACU36 .....FACU.35Canadian goldenrod Solidago canadensis L FACWY2440Jewel Weed Impatiens capensis Meerb. FACU.1830Garlic mustard Alliaria petiolata (M. Bieb.) Cavara & Grande MA Indicator.1830Sphagnum FACUY7340Multiflora Rose Rosa Multiflora ..1810Woody Shrub? ..... FACU.55Virginia Creeper . .... FACWY2630Silv Maple Acer saccharinum L FACUY2630Black Locust Robinia pseudoacacia L FAC.1315Northern Catalpa FACWY3540Black Ash Fraxinus nigra Marshall ..... 3 3 36 Hampden St Northampton /165 /115 /55 7-15-2019 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/2 O organic 0-0.5 A .0.5.-1.5 Many 10YR 4/4/& 3/6 .. B 1.5-5 10YR 4/1 . Faint/Few 10YR4/6 None 10YR 4/15-15B1 Wind thrown trees MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 4 .1and 2 J. Knot Weed Polygonum cuspidatum Siebold & Zucc 40 Y FACU17 .....FACWY2250Canadian Clearweed Pilea pumila (L.) A. Gray FACWY2660Jewel Weed Impatiens capensis Meerb. ?.1330Virginia Knotweed Polygonum virginianum L FAC.410Avens white Geum canadense Jacq . ... Poison Ivy Toxicodendron radicans MA Indicator ... Sphagnum FACY335 . FACUY6710 N Catalpa exp roots FACWY4460Black Ash Fraxinus nigra Marshall FACW.1115Silv Maple Acer saccharinum L FACU.1520Black Locust Robinia pseudoacacia L FACY2525N Catalpa Exp Roots Catalpa speciosa FACWY3040 Multiflora Rose Rosa Multiflora .... .3 or 4 36 Hampden St Northampton /15 /135 Black Ash Sap Fraxinus nigra Marshall 40 30 Y V Creeper Parthenocissus quinquefolia 30 40 Y FACU MA Indicator . ..MA Indicator..MA IndicatorY1740/230 /70 6 7-15-2019 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/1O organic 0-1 A Sandy Loam 1-6 None . B Silt Loam 6-14 10YR 3/2 None 10YR 5/1 Wind Thrown trees and exposed roots MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 5 .2 J. Knot Weed, Polygonum cuspidatum Siebold & Zucc 80 Y FACU81 .....FACWN.2Canadian Clearweed, Pilea pumila (L.) A. Gray FACWN1010Jewel Weed, Impatiens capensis Meerb. FACUN88Garlic Mustard, Alliaria petiolata (M. Bieb.) Cavara & Grande ..... . ... Grapevine Vitis aestivalis MA Indicator ... . FACU Not absolute on speciesY1005 . .... N Catalpa exp roots FACWY6060Black Ash, Fraxinus nigra Marshall ..... FACUY2020Black Locust, Robinia pseudoacacia L .Y2525. FACUY4040 ..... .4 36 Hampden St Northampton . . Black Walnut, Juglans nigra L. ... . .... MA Indicator . ..MA Indicator...... /98 . 1 7-15-2019 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/1O organic 0-1 A Sandy Loam 1-6 None . B Loamy Sand 6-15 10YR 4/1 None 10YR 4/3 Motteling beginning about 8" down for the depth. >6" MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 6 .2 See second page for ground cover herbaceous layer .... ........... ??5030Unknown Honeysuckle FACUN5030Multiflora Rose Rosa Multiflora ..... FACW ... Sap Black Ash, Fraxinus nigra Marshall MA Indicator .2510 Sap Blk Walnut, Juglans nigra L. FACW Y5020 Sap Norway Mapl, Acer platanoides L. ..... FACWN920Black Ash, Fraxinus nigra Marshall FACWY3270Green ash Fraxinus pennsilvanica Marshall UPLN920 Black Locust, Robinia pseudoacacia L FACWY2525Silver Maple Acer saccharinum L FACUN920 Catalpia Catalpa speciosa .... .6 36 Hampden St Northampton /40 . Black Walnut, Juglans nigra L. 20 9 N Norway Maple, Acer platanoides L 70 32 Y FAC This tree uprooting MA Indicator Y ..MA Indicator..FACUY2510 /60 /220 4 7-15-2019 . MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 6 .2 J. Knot Weed, Polygonum cuspidatum Siebold & Zucc 30 Y FACU16 .....FACN610Virginia Knotweed Polygonum Virginianum L. FACWY4480Can Clearweed Pilea Pumila FACUN610Common Ragweed, Ambrosia artemisiifolia OBLN610Skunk cabbage Symplocarpus foetidus FAC ... Mustard Garlic Alliaria petiolata .610 Sphagnum Moss FACU N1120 Jack in Pulpit, Ambrosia artemisiifolia .... N Catalpa exp roots FACUY6020Virginia Creeper Parthenocissus quinquefolia FACY255Poison Ivy, Toxicodendron radicans ?Y (assume)5010Unknown Vine FACUY2525Grape Vitis aestivalis .... ..... .See previous page 36 Hampden St Northampton . . . 5 25 Y . .... N ..MA IndicatorN.N610 /180 . See previous page 7-15-2019 /20 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/1O organic 0-0.5 A Silty Loam 0.5-20 None 4" X . .. 10YR 4/1 2.5YR 5/8 faint @4" 20% 12-20. X Wind Thrown Trees observed MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 7 .2 See second page for ground cover herbaceous layer .... ........... ?N95Unknown Honeysuckle FACUY9050Multiflora Rose Rosa Multiflora ..... ...MA Indicator ... ... ..... ..... FACWY2030Green ash Fraxinus pennsilvanica Marshall UPLN1320 Black Locust, Robinia pseudoacacia L FACWY2525Silver Maple Acer saccharinum L .... Catalpia Catalpa speciosa .... .4 36 Hampden St Northampton . . . 50 33 Y Norway Maple, Acer platanoides L 50 33 Y FAC This tree uprooting . ..MA Indicator..... /55 /150 6 7-15-2019 . MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 7 .2 Sensitive fern, Onoclea sensibilis 50 Y FACU5 ......... FACWY2020Can Clearweed Pilea Pumila FACWY2020Jewelweed, Impatiens pallida OBLN55Small Spike False Nettle, Boehmeria cylindrica FAC ... . .55 . . ... Jack in Pulpit, Ambrosia artemisiifolia .... N Catalpa exp roots FACUY4315Virginia Creeper Parthenocissus quinquefolia FACY2810Poison Ivy, Toxicodendron radicans ..... FACUY2525Grape Vitis aestivalis .... ..... .See previous page 36 Hampden St Northampton . . . 10 28 Y . .... N ...N.... /100 . See previous page 7-15-2019 /35 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/1O Silty Muck 0-4 A Silty Loam 4-18 None X Earlier in spring . X . .. 10YR 4/2 2.5YR 4/6 few Dark Surface streaking. Observed flooding earlier in spring, and water stained leaves MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 8 .2 ..... ........... FAC Water stain on trunkY2325Cottonwood, Populus deltoides FACUN1415Black Locust, Robinia pseudoacacia L FACWY6470Silver Maple Acer saccharinum L UPL ... Multiflora Rose, Rosa Multiflora MA Indicator .6015 FACU Y4010 Sap Norway Mapl, Acer platanoides L. ..... .... FACWY5050Sensitive Fern Onoclea sensibilis L. FACWY2020 Black Locust, Robinia pseudoacacia L FACUY2525Mustard Garlic Alliaria petiolata .... J. Knot Weed, Polygonum cuspidatum Siebold & Zucc .... .3 36 Hampden St Northampton /25 . . 10 10 N Canada Wood Nettle? Laportea canadensis? 20 20 Y FACU MA Indicator Y ..MA Indicator..... /110 /100 4 7-15-2019 . Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X . X X . Web Soil Survey, Attached X . . ... X X MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 9 3 See second page for ground cover herbaceous layer .... .......... ..... ..... ..... FACW ... Sap Black Ash, Fraxinus nigra Marshall MA Indicator .145 . FACW Y2910 Sap Norway Mapl, Acer platanoides L. FACWY5720. FACWN1720Black Ash, Fraxinus nigra Marshall N910Black Locust, Robinia pseudoacacia FACN1315 Black Locust, Robinia pseudoacacia L FACWY2525Silver Maple Acer saccharinum L .... ..... .2 36 Hampden St Northampton /35 . . 70 61 Y Eastern Cottonwood, Populus Deltoides .... MA Indicator N ..MA Indicator...... . /115 3 7-15-2019 . Sap Silver Maple Acer saccharinum L FACU MassDEP Bordering Vegetated Wetland (310 CMR 10.55) Delineation Field Data Form Applicant:_________________________ Prepared by:______________________ Project location:__________________ DEP File #:_______________ Check all that apply: Vegetation alone presumed adequate to delineate BVW boundary: fill out Section I only Vegetation and other indicators of hydrology usedto delineateBVW boundary: fill out Sections I and II Method other than dominance test used (attach additional information) Section I. Vegetation Observation Plot Number:Transect Number:Date of Delineation: A. Sample Layer & Plant Species (by common/scientific name) B. Percent Cover (or basal Area) C. Percent Dominance D. Dominant Plant (yes or no)E. Wetland Indicator Category* * Use an asterisk to mark wetland indicator plants: plant species listed in the Wetlands Protection Act (MGL c.131, s.40); plants in the genus Sphagnum; plants listed as FAC, FAC+, FACW-, FACW, FACW+, or OBL; or plants with physiological or morphological adaptations. If any plants are identified as wetland indicator plants due t o physiological or morphological adaptations, describe the adaptation next to the asterisk. Vegetation conclusion: Number of dominant wetland indicator plants: Number of dominant non-wetland indicator plants: Pioneer Development, LLC John Wallen PE The Engineer Group, LLC X 9 3 J. Knot Weed, Polygonum cuspidatum Siebold & Zucc 85 Y FACU70 .....FACN45Virginia Knotweed Polygonum Virginianum L. FACWN45Skunk Cabage, Symplocarpus foetidus FACWN45Jewelweed, Impatiens pallida ..... ... Mustard Garlic Alliaria petiolata .. Sphagnum Moss FACU N45 .... N Catalpa exp roots FACUY10010Virginia Creeper Parthenocissus quinquefolia ..... ..... .Y2525. .... ..... .See previous page 36 Hampden St Northampton . . . ... . .... ..MA Indicator.N1215 /120 . See previous page 7-15-2019 /10 Is the number of dominant wetland plants equal to or greater than the number of dominant non-wetland plants? yes no If vegetation alone is presumed adequate to delineate the BVW boundary, submit this form with the Request for Determination of Applicability or Notice of Intent Section II. Indicators of Hydrology Hydric Soil Interpretation 1. Soil Survey Is there a published soil survey for this site? yes no title/date: map number: soil type mapped: hydric soil inclusions: Are field observations consistent with soil survey? yes no Remarks: 2. Soil Description Horizon Depth Matrix Color Mottles Color Remarks: 3. Other: Conclusion: Is soil hydric? yes no Other Indicators of Hydrology: (check all that apply & describe) Site Inundated: __________________________________ Depth to free water in observation hole: _______________ Depth to soil saturation in observation hole: ____________ Water marks: ____________________________________ Drift lines: _______________________________________ Sediment Deposits: ________________________________ Drainage patterns in BVW: __________________________ Oxidized rhizospheres: _____________________________ Water-stained leaves: ______________________________ Recorded Data (streams, lake, or tidal gauge; aerial photo; other): ________________________________________________________ ________________________________________________________ ________________________________________________________ Other: __________________________________________________ Vegetation and Hydrology Conclusion Yes No Number of wetland indicator plants > # of non-wetland indicator plants ____ ____ Wetland hydrology present: Hydric soil present _________ Other indicators of hydrology present _________ Sample location is in a BVW _________ Submit this form with the Request for Determination of Applicability or Notice of Intent. X X X X Yes Web Soil Survey, Attached O 0-6 10YR 3/1O Silty Muck 0-1 A1 Silty Loam 1-3 None X . .A2 Silty loam . .3-18 10YR 4/1 Soil moist, no mottles .10YR 4/3 Seeping water traverses the area in spring, and blown down trees in area The Engineer Group LLC 413-626-8167 36 Hampden St Northampton, MA MA Notice Of Intent Storm Water Report FIGURE 5 Existing , Proposed Conditions and Stormwater See Full Size Drawings 1-5 5-30-2020