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Stormwater Drainage Report ............................................................................................................................ 1-1 .................................................................................................................... 2-1 ................................................................................................... 2-1 .......................................................................................................................... 2-1 ................................................................................................................................... 2-1 ..................................................... 2-2 ................................................................................................... 2-2 ............................................................................................................................................... 2-2 ................................................................................................ 2-2 ........................................................................ 3-1 ............................................................................................................. 3-1 .............................................................................................................................. 3-2 .................................................................................................. 3-2 ................................................................................................ 3-2 ............................................................................................................... 3-2 ..................................................................................................................... 3-3 ................................................................ 3-3 ............................................................................. 3-6 ....................................................................................... 3-6 .................................................................................................................. 3-6 ............. 3-6 ................. 3-7 .............................................................................. 3-7 ............................................ 3-7 .......................................................... 3-7 ................................................................................................................................ 4-1              R L A SCALE: DATE: JOB NO: ph: 413.568.0985 fax: 413.568.0986 rlaland.com 40 School Street · P.O. Box 640 · Westfield, MA 01086 R LEVESQUE ASSOCIATES, INC A Land Planning Services Company 210226 9/10/2021 AS NOTED Sovereign Builders Inc. c/o Todd Cellura 710 Southampton Rd. Westfield, MA Proposed Residential Development 29 Sherman Ave Northampton, MA 01060 SITE R L A SCALE: DATE: JOB NO: ph: 413.568.0985 fax: 413.568.0986 rlaland.com 40 School Street · P.O. Box 640 · Westfield, MA 01086 R LEVESQUE ASSOCIATES, INC A Land Planning Services Company 210226 9/10/2021 AS NOTED Sovereign Builders Inc. c/o Todd Cellura 710 Southampton Rd. Westfield, MA Proposed Residential Development 29 Sherman Ave Northampton, MA 01060 FIG-1 SITE LOCUS USGS MAP SITE R L A SCALE: DATE: JOB NO: ph: 413.568.0985 fax: 413.568.0986 rlaland.com 40 School Street · P.O. Box 640 · Westfield, MA 01086 R LEVESQUE ASSOCIATES, INC A Land Planning Services Company 210226 9/10/2021 AS NOTED Sovereign Builders Inc. c/o Todd Cellura 710 Southampton Rd. Westfield, MA Proposed Residential Development 29 Sherman Ave Northampton, MA 01060 FIG-2 FLOOD RATE INSURANCE MAP R L A SCALE: DATE: JOB NO: ph: 413.568.0985 fax: 413.568.0986 rlaland.com 40 School Street · P.O. Box 640 · Westfield, MA 01086 R LEVESQUE ASSOCIATES, INC A Land Planning Services Company 210226 9/10/2021 AS NOTED Sovereign Builders Inc. c/o Todd Cellura 710 Southampton Rd. Westfield, MA Proposed Residential Development 29 Sherman Ave Nothampton, MA 01060 SITE FIG-3 NHESP & Zone II Map NHESP BOUNDARY SHERMAN AVENUE 741A Amostown-Windsor Silty Substratum-Urban Land Complex Hydrologic Group: B SCALE: DATE: JOB NO.:ph: 413.568.0985 fax: 413.568.0986 rlaland.com40 School Street · P.O. Box 640 · Westfield, MA 01086R LEVESQUE ASSOCIATES, INCA Land Planning Services CompanyPre-DevelopmentWatershed PlanProposed Residential Complex29 sherman Ave.Northampton, MASovereign Builders710 Southampton RoadWestfield, MA 01085210226 09/10/2021 As Noted FIG-4 SHERMAN AVENUESHERMAN AVENUE 741A Amostown-Windsor Silty Substratum-Urban Land Complex Hydrologic Group: B SCALE: DATE: JOB NO.:ph: 413.568.0985 fax: 413.568.0986 rlaland.com40 School Street · P.O. Box 640 · Westfield, MA 01086R LEVESQUE ASSOCIATES, INCA Land Planning Services CompanyPost-DevelopmentWatershed PlanProposed Residential Complex29 sherman Ave.Northampton, MASovereign Builders710 Southampton RoadWestfield, MA 01085210226 07/16/2021 As Noted FIG-5 SHERMAN AVENUESHERMAN AVENUE 741A Amostown-Windsor Silty Substratum-Urban Land Complex Hydrologic Group: B SCALE: DATE: JOB NO.:ph: 413.568.0985 fax: 413.568.0986 rlaland.com40 School Street · P.O. Box 640 · Westfield, MA 01086R LEVESQUE ASSOCIATES, INCA Land Planning Services CompanyInlet AreaWatershed PlanProposed Residential Complex29 sherman Ave.Northampton, MASovereign Builders710 Southampton RoadWestfield, MA 01085210226 09/10/2021 As Noted FIG-6 MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report A. Introduction Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key. A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in Volume 3 of the Massachusetts Stormwater Handbook. The Stormwater Report must be prepared and certified by a Registered Professional Engineer (RPE) licensed in the Commonwealth. The Stormwater Report must include:  The Stormwater Checklist completed and stamped by a Registered Professional Engineer (see page 2) that certifies that the Stormwater Report contains all required submittals.1 This Checklist is to be used as the cover for the completed Stormwater Report.  Applicant/Project Name  Project Address  Name of Firm and Registered Professional Engineer that prepared the Report  Long-Term Pollution Prevention Plan required by Standards 4-6  Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82  Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 1 The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report, the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex projects, it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event, the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report. The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable (N.A.) and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer’s Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement (if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? New development Redevelopment Mix of New Development and Redevelopment MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Pervious Pavers 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. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 2: Peak Rate Attenuation Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge Soil Analysis provided. Required Recharge Volume calculation provided. Required Recharge volume reduced through use of the LID site Design Credits. Sizing the infiltration, BMPs is based on the following method: Check the method used. Static Simple Dynamic Dynamic Field1 Runoff from all impervious areas at the site discharging to the infiltration BMP. Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume. Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: Site is comprised solely of C and D soils and/or bedrock at the land surface M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 Solid Waste Landfill pursuant to 310 CMR 19.000 Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. Calculations showing that the infiltration BMPs will drain in 72 hours are provided. Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included. 1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following: Good housekeeping practices; Provisions for storing materials and waste products inside or under cover; Vehicle washing controls; Requirements for routine inspections and maintenance of stormwater BMPs; Spill prevention and response plans; Provisions for maintenance of lawns, gardens, and other landscaped areas; Requirements for storage and use of fertilizers, herbicides, and pesticides; Pet waste management provisions; Provisions for operation and management of septic systems; Provisions for solid waste management; Snow disposal and plowing plans relative to Wetland Resource Areas; Winter Road Salt and/or Sand Use and Storage restrictions; Street sweeping schedules; Provisions for prevention of illicit discharges to the stormwater management system; Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. Treatment BMPs subject to the 44% TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: is within the Zone II or Interim Wellhead Protection Area is near or to other critical areas is within soils with a rapid infiltration rate (greater than 2.4 inches per hour) involves runoff from land uses with higher potential pollutant loads. The Required Water Quality Volume is reduced through use of the LID site Design Credits. Calculations documenting that the treatment train meets the 80% TSS removal requirement and, if applicable, the 44% TSS removal pretreatment requirement, are provided. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 6 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 4: Water Quality (continued) The BMP is sized (and calculations provided) based on: The ½” or 1” Water Quality Volume or The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. The NPDES Multi-Sector General Permit does not cover the land use. LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. All exposure has been eliminated. All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease (e.g. all parking lots with >1000 vehicle trips per day) and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. Critical areas and BMPs are identified in the Stormwater Report. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: Limited Project Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff Bike Path and/or Foot Path Redevelopment Project Redevelopment portion of mix of new and redevelopment. Certain standards are not fully met (Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a) complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: Narrative; Construction Period Operation and Maintenance Plan; Names of Persons or Entity Responsible for Plan Compliance; Construction Period Pollution Prevention Measures; Erosion and Sedimentation Control Plan Drawings; Detail drawings and specifications for erosion control BMPs, including sizing calculations; Vegetation Planning; Site Development Plan; Construction Sequencing Plan; Sequencing of Erosion and Sedimentation Controls; Operation and Maintenance of Erosion and Sedimentation Controls; Inspection Schedule; Maintenance Schedule; Inspection and Maintenance Log Form. A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. MassDEP Stormwater Checklist - 2016-05-23.doc • 04/01/08 Stormwater Report Checklist • Page 8 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. The project is not covered by a NPDES Construction General Permit. The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: Name of the stormwater management system owners; Party responsible for operation and maintenance; Schedule for implementation of routine and non-routine maintenance tasks; Plan showing the location of all stormwater BMPs maintenance access areas; Description and delineation of public safety features; Estimated operation and maintenance budget; and Operation and Maintenance Log Form. The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: A copy of the legal instrument (deed, homeowner’s association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; An Illicit Discharge Compliance Statement is attached; NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. 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 Natural Resources Conservation Service July 13, 2021 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 741A—Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes....................................................................................14 References............................................................................................................16 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 468929046893004689310468932046893304689340468935046893604689300468931046893204689330468934046893504689360695660 695670 695680 695690 695700 695710 695720 695730 695740 695750 695760 695660 695670 695680 695690 695700 695710 695720 695730 695740 695750 695760 695770 42° 19' 54'' N 72° 37' 30'' W42° 19' 54'' N72° 37' 25'' W42° 19' 52'' N 72° 37' 30'' W42° 19' 52'' N 72° 37' 25'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 25 50 100 150 Feet 0 5 10 20 30 Meters Map Scale: 1:534 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:15,800. 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 15, Jun 9, 2020 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 741A Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes 0.7 100.0% Totals for Area of Interest 0.7 100.0% 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 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, Custom Soil Resource Report 12 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 741A—Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 99z2 Elevation: 100 to 330 feet Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 120 to 240 days Farmland classification: Not prime farmland Map Unit Composition Amostown and similar soils:35 percent Windsor, silty substratum, and similar soils:25 percent Urban land:25 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Amostown Setting Landform:Deltas, outwash plains, terraces Landform position (two-dimensional):Summit, footslope Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Friable sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 7 inches: fine sandy loam H2 - 7 to 32 inches: fine sandy loam H3 - 32 to 60 inches: stratified very fine sand to silt loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:High (about 9.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Ecological site: F145XY005MA - Moist Lake Plain Hydric soil rating: No Custom Soil Resource Report 14 Description of Windsor, Silty Substratum Setting Landform:Outwash plains Landform position (two-dimensional):Footslope Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Loose sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 8 inches: loamy sand H2 - 8 to 21 inches: loamy sand H3 - 21 to 45 inches: sand H4 - 45 to 60 inches: silt loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to 0.60 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F144AY022MA - Dry Outwash Hydric soil rating: No Minor Components Enosburg Percent of map unit:10 percent Landform:Terraces Hydric soil rating: Yes Maybid Percent of map unit:5 percent Landform:Depressions Hydric soil rating: Yes Custom Soil Resource Report 15 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 16 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 17 ES-1 ES-2 Subcat ES-2 DP-1 On Site Low Point DP-2 Offsite to West/Southwest & Sherman Ave Routing Diagram for 210226 - PRE Prepared by {enter your company name here}, Printed 7/27/2021 HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcat Reach Pond Link 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 2HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=21,582 sf 26.77% Impervious Runoff Depth=1.10"Subcatchment ES-1: Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ Runoff=0.35 cfs 1,970 cf Runoff Area=7,079 sf 48.57% Impervious Runoff Depth=1.62"Subcatchment ES-2: Subcat ES-2 Flow Length=258' Tc=14.6 min CN=WQ Runoff=0.20 cfs 957 cf Inflow=0.35 cfs 1,970 cfLink DP-1: On Site Low Point Primary=0.35 cfs 1,970 cf Inflow=0.20 cfs 957 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.20 cfs 957 cf Total Runoff Area = 28,662 sf Runoff Volume = 2,926 cf Average Runoff Depth = 1.23" 67.84% Pervious = 19,445 sf 32.16% Impervious = 9,217 sf 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 3HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-1: Runoff = 0.35 cfs @ 12.27 hrs, Volume= 1,970 cf, Depth= 1.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 14,783 61 >75% Grass cover, Good, HSG B 867 96 Gravel surface, HSG B 658 98 Paved parking, HSG B 5,120 98 Roofs, HSG B 155 55 Woods, Good, HSG B 21,582 Weighted Average 15,804 63 73.23% Pervious Area 5,779 98 26.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 19.4 151 0.0090 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" Subcatchment ES-1: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=21,582 sf Runoff Volume=1,970 cf Runoff Depth=1.10" Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ 0.35 cfs 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 4HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-2: Subcat ES-2 Runoff = 0.20 cfs @ 12.20 hrs, Volume= 957 cf, Depth= 1.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 3,336 61 >75% Grass cover, Good, HSG B 290 96 Gravel surface, HSG B 1,778 98 Paved parking, HSG B 1,661 98 Roofs, HSG B 14 55 Woods, Good, HSG B 7,079 Weighted Average 3,641 64 51.43% Pervious Area 3,439 98 48.57% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.7 152 0.0260 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.6 25 0.0080 0.70 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.00" 1.3 81 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 14.6 258 Total 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 5HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcatchment ES-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=3.00" Runoff Area=7,079 sf Runoff Volume=957 cf Runoff Depth=1.62" Flow Length=258' Tc=14.6 min CN=WQ 0.20 cfs 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 6HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 21,582 sf, 26.77% Impervious, Inflow Depth = 1.10" for 2-Year event Inflow = 0.35 cfs @ 12.27 hrs, Volume= 1,970 cf Primary = 0.35 cfs @ 12.27 hrs, Volume= 1,970 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=21,582 sf 0.35 cfs 0.35 cfs 210226 - PRE Type III 24-hr 2-Year Rainfall=3.00"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 7HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 7,079 sf, 48.57% Impervious, Inflow Depth = 1.62" for 2-Year event Inflow = 0.20 cfs @ 12.20 hrs, Volume= 957 cf Primary = 0.20 cfs @ 12.20 hrs, Volume= 957 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Inflow Area=7,079 sf 0.20 cfs 0.20 cfs 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 8HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=21,582 sf 26.77% Impervious Runoff Depth=2.12"Subcatchment ES-1: Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ Runoff=0.74 cfs 3,809 cf Runoff Area=7,079 sf 48.57% Impervious Runoff Depth=2.83"Subcatchment ES-2: Subcat ES-2 Flow Length=258' Tc=14.6 min CN=WQ Runoff=0.36 cfs 1,667 cf Inflow=0.74 cfs 3,809 cfLink DP-1: On Site Low Point Primary=0.74 cfs 3,809 cf Inflow=0.36 cfs 1,667 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.36 cfs 1,667 cf Total Runoff Area = 28,662 sf Runoff Volume = 5,476 cf Average Runoff Depth = 2.29" 67.84% Pervious = 19,445 sf 32.16% Impervious = 9,217 sf 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 9HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-1: Runoff = 0.74 cfs @ 12.27 hrs, Volume= 3,809 cf, Depth= 2.12" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 10-Year Rainfall=4.60" Area (sf) CN Description 14,783 61 >75% Grass cover, Good, HSG B 867 96 Gravel surface, HSG B 658 98 Paved parking, HSG B 5,120 98 Roofs, HSG B 155 55 Woods, Good, HSG B 21,582 Weighted Average 15,804 63 73.23% Pervious Area 5,779 98 26.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 19.4 151 0.0090 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" Subcatchment ES-1: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=4.60" Runoff Area=21,582 sf Runoff Volume=3,809 cf Runoff Depth=2.12" Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ 0.74 cfs 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 10HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-2: Subcat ES-2 Runoff = 0.36 cfs @ 12.20 hrs, Volume= 1,667 cf, Depth= 2.83" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 10-Year Rainfall=4.60" Area (sf) CN Description 3,336 61 >75% Grass cover, Good, HSG B 290 96 Gravel surface, HSG B 1,778 98 Paved parking, HSG B 1,661 98 Roofs, HSG B 14 55 Woods, Good, HSG B 7,079 Weighted Average 3,641 64 51.43% Pervious Area 3,439 98 48.57% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.7 152 0.0260 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.6 25 0.0080 0.70 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.00" 1.3 81 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 14.6 258 Total 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 11HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcatchment ES-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Type III 24-hr 10-Year Rainfall=4.60" Runoff Area=7,079 sf Runoff Volume=1,667 cf Runoff Depth=2.83" Flow Length=258' Tc=14.6 min CN=WQ 0.36 cfs 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 12HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 21,582 sf, 26.77% Impervious, Inflow Depth = 2.12" for 10-Year event Inflow = 0.74 cfs @ 12.27 hrs, Volume= 3,809 cf Primary = 0.74 cfs @ 12.27 hrs, Volume= 3,809 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Inflow Area=21,582 sf 0.74 cfs 0.74 cfs 210226 - PRE Type III 24-hr 10-Year Rainfall=4.60"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 13HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 7,079 sf, 48.57% Impervious, Inflow Depth = 2.83" for 10-Year event Inflow = 0.36 cfs @ 12.20 hrs, Volume= 1,667 cf Primary = 0.36 cfs @ 12.20 hrs, Volume= 1,667 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=7,079 sf 0.36 cfs 0.36 cfs 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 14HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=21,582 sf 26.77% Impervious Runoff Depth=3.54"Subcatchment ES-1: Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ Runoff=1.28 cfs 6,365 cf Runoff Area=7,079 sf 48.57% Impervious Runoff Depth=4.40"Subcatchment ES-2: Subcat ES-2 Flow Length=258' Tc=14.6 min CN=WQ Runoff=0.57 cfs 2,595 cf Inflow=1.28 cfs 6,365 cfLink DP-1: On Site Low Point Primary=1.28 cfs 6,365 cf Inflow=0.57 cfs 2,595 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.57 cfs 2,595 cf Total Runoff Area = 28,662 sf Runoff Volume = 8,960 cf Average Runoff Depth = 3.75" 67.84% Pervious = 19,445 sf 32.16% Impervious = 9,217 sf 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 15HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-1: Runoff = 1.28 cfs @ 12.27 hrs, Volume= 6,365 cf, Depth= 3.54" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 14,783 61 >75% Grass cover, Good, HSG B 867 96 Gravel surface, HSG B 658 98 Paved parking, HSG B 5,120 98 Roofs, HSG B 155 55 Woods, Good, HSG B 21,582 Weighted Average 15,804 63 73.23% Pervious Area 5,779 98 26.77% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 19.4 151 0.0090 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" Subcatchment ES-1: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 100-Year Rainfall=6.50" Runoff Area=21,582 sf Runoff Volume=6,365 cf Runoff Depth=3.54" Flow Length=151' Slope=0.0090 '/' Tc=19.4 min CN=WQ 1.28 cfs 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 16HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ES-2: Subcat ES-2 Runoff = 0.57 cfs @ 12.20 hrs, Volume= 2,595 cf, Depth= 4.40" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 3,336 61 >75% Grass cover, Good, HSG B 290 96 Gravel surface, HSG B 1,778 98 Paved parking, HSG B 1,661 98 Roofs, HSG B 14 55 Woods, Good, HSG B 7,079 Weighted Average 3,641 64 51.43% Pervious Area 3,439 98 48.57% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.7 152 0.0260 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.6 25 0.0080 0.70 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.00" 1.3 81 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 14.6 258 Total 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 17HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcatchment ES-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 100-Year Rainfall=6.50" Runoff Area=7,079 sf Runoff Volume=2,595 cf Runoff Depth=4.40" Flow Length=258' Tc=14.6 min CN=WQ 0.57 cfs 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 18HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 21,582 sf, 26.77% Impervious, Inflow Depth = 3.54" for 100-Year event Inflow = 1.28 cfs @ 12.27 hrs, Volume= 6,365 cf Primary = 1.28 cfs @ 12.27 hrs, Volume= 6,365 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=21,582 sf 1.28 cfs 1.28 cfs 210226 - PRE Type III 24-hr 100-Year Rainfall=6.50"210226 - PRE Printed 7/27/2021Prepared by {enter your company name here} Page 19HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 7,079 sf, 48.57% Impervious, Inflow Depth = 4.40" for 100-Year event Inflow = 0.57 cfs @ 12.20 hrs, Volume= 2,595 cf Primary = 0.57 cfs @ 12.20 hrs, Volume= 2,595 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=7,079 sf 0.57 cfs 0.57 cfs PS-1A PS-1B PS-2 Subcat ES-2 1P Bioretention Area DP-1 On Site Low Point DP-2 Offsite to West/Southwest & Sherman Ave Routing Diagram for 210226 - POST_2 Prepared by {enter your company name here}, Printed 9/14/2021 HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcat Reach Pond Link 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 2HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=5,875 sf 100.00% Impervious Runoff Depth=2.77"Subcatchment PS-1A: Tc=6.0 min CN=WQ Runoff=0.39 cfs 1,355 cf Runoff Area=16,550 sf 14.79% Impervious Runoff Depth=0.75"Subcatchment PS-1B: Flow Length=152' Tc=11.8 min CN=WQ Runoff=0.20 cfs 1,039 cf Runoff Area=6,236 sf 33.19% Impervious Runoff Depth=1.16"Subcatchment PS-2: Subcat ES-2 Flow Length=244' Tc=13.6 min CN=WQ Runoff=0.12 cfs 604 cf Peak Elev=129.76' Storage=631 cf Inflow=0.39 cfs 1,355 cfPond 1P: Bioretention Area Discarded=0.02 cfs 1,355 cf Primary=0.00 cfs 0 cf Outflow=0.02 cfs 1,355 cf Inflow=0.20 cfs 1,039 cfLink DP-1: On Site Low Point Primary=0.20 cfs 1,039 cf Inflow=0.12 cfs 604 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.12 cfs 604 cf Total Runoff Area = 28,661 sf Runoff Volume = 2,999 cf Average Runoff Depth = 1.26" 63.74% Pervious = 18,268 sf 36.26% Impervious = 10,393 sf 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 3HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1A: Runoff = 0.39 cfs @ 12.08 hrs, Volume= 1,355 cf, Depth= 2.77" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 0 61 >75% Grass cover, Good, HSG B 3,325 98 Paved parking, HSG B 2,550 98 Roofs, HSG B 5,875 Weighted Average 0 61 0.00% Pervious Area 5,875 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PS-1A: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=5,875 sf Runoff Volume=1,355 cf Runoff Depth=2.77" Tc=6.0 min CN=WQ 0.39 cfs 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 4HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1B: Runoff = 0.20 cfs @ 12.18 hrs, Volume= 1,039 cf, Depth= 0.75" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 13,854 61 >75% Grass cover, Good, HSG B 248 96 Gravel surface, HSG B 345 98 Paved parking, HSG B 1,411 98 Roofs, HSG B 692 98 Water Surface, HSG B 16,550 Weighted Average 14,102 62 85.21% Pervious Area 2,448 98 14.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 143 0.0280 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.0 9 0.3330 9.29 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 11.8 152 Total Subcatchment PS-1B: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=3.00" Runoff Area=16,550 sf Runoff Volume=1,039 cf Runoff Depth=0.75" Flow Length=152' Tc=11.8 min CN=WQ 0.20 cfs 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 5HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-2: Subcat ES-2 Runoff = 0.12 cfs @ 12.19 hrs, Volume= 604 cf, Depth= 1.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 4,166 61 >75% Grass cover, Good, HSG B 2,070 98 Paved parking, HSG B 6,236 Weighted Average 4,166 61 66.81% Pervious Area 2,070 98 33.19% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 125 0.0220 0.18 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 2.0 119 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 13.6 244 Total Subcatchment PS-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)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=3.00" Runoff Area=6,236 sf Runoff Volume=604 cf Runoff Depth=1.16" Flow Length=244' Tc=13.6 min CN=WQ 0.12 cfs 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 6HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Pond 1P: Bioretention Area Inflow Area = 5,875 sf,100.00% Impervious, Inflow Depth = 2.77" for 2-Year event Inflow = 0.39 cfs @ 12.08 hrs, Volume= 1,355 cf Outflow = 0.02 cfs @ 13.79 hrs, Volume= 1,355 cf, Atten= 94%, Lag= 102.1 min Discarded = 0.02 cfs @ 13.79 hrs, Volume= 1,355 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 129.76' @ 13.79 hrs Surf.Area= 967 sf Storage= 631 cf Plug-Flow detention time= 256.0 min calculated for 1,355 cf (100% of inflow) Center-of-Mass det. time= 255.9 min ( 1,013.7 - 757.8 ) Volume Invert Avail.Storage Storage Description #1 129.00' 4,061 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 129.00 692 123.0 0 0 692 130.00 1,062 133.0 870 870 933 131.00 1,490 152.0 1,270 2,140 1,386 132.00 2,387 251.0 1,921 4,061 4,568 Device Routing Invert Outlet Devices #1 Discarded 129.00'1.020 in/hr Exfiltration over Surface area #2 Primary 123.41'16.0" Round Culvert L= 10.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 123.41' / 123.31' S= 0.0100 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.40 sf #3 Device 2 130.66'8.0" Horiz. OCS-1 X 0.75 C= 0.600 Limited to weir flow at low heads #4 Device 2 131.62'24.0" x 24.0" Horiz. Existing Catch Basin C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.02 cfs @ 13.79 hrs HW=129.76' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' (Free Discharge) 2=Culvert (Passes 0.00 cfs of 11.78 cfs potential flow) 3=OCS-1 ( Controls 0.00 cfs) 4=Existing Catch Basin ( Controls 0.00 cfs) 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 7HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Pond 1P: Bioretention Area Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=5,875 sf Peak Elev=129.76' Storage=631 cf 0.39 cfs 0.02 cfs 0.02 cfs 0.00 cfs 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 8HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 22,425 sf, 37.12% Impervious, Inflow Depth = 0.56" for 2-Year event Inflow = 0.20 cfs @ 12.18 hrs, Volume= 1,039 cf Primary = 0.20 cfs @ 12.18 hrs, Volume= 1,039 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Inflow Area=22,425 sf 0.20 cfs 0.20 cfs 210226 - POST Type III 24-hr 2-Year Rainfall=3.00"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 9HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 6,236 sf, 33.19% Impervious, Inflow Depth = 1.16" for 2-Year event Inflow = 0.12 cfs @ 12.19 hrs, Volume= 604 cf Primary = 0.12 cfs @ 12.19 hrs, Volume= 604 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)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=6,236 sf 0.12 cfs 0.12 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 10HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=5,875 sf 100.00% Impervious Runoff Depth=4.36"Subcatchment PS-1A: Tc=6.0 min CN=WQ Runoff=0.60 cfs 2,137 cf Runoff Area=16,550 sf 14.79% Impervious Runoff Depth=1.66"Subcatchment PS-1B: Flow Length=152' Tc=11.8 min CN=WQ Runoff=0.53 cfs 2,287 cf Runoff Area=6,236 sf 33.19% Impervious Runoff Depth=2.21"Subcatchment PS-2: Subcat ES-2 Flow Length=244' Tc=13.6 min CN=WQ Runoff=0.25 cfs 1,147 cf Peak Elev=130.23' Storage=1,126 cf Inflow=0.60 cfs 2,137 cfPond 1P: Bioretention Area Discarded=0.03 cfs 2,137 cf Primary=0.00 cfs 0 cf Outflow=0.03 cfs 2,137 cf Inflow=0.53 cfs 2,287 cfLink DP-1: On Site Low Point Primary=0.53 cfs 2,287 cf Inflow=0.25 cfs 1,147 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.25 cfs 1,147 cf Total Runoff Area = 28,661 sf Runoff Volume = 5,570 cf Average Runoff Depth = 2.33" 63.74% Pervious = 18,268 sf 36.26% Impervious = 10,393 sf 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 11HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1A: Runoff = 0.60 cfs @ 12.08 hrs, Volume= 2,137 cf, Depth= 4.36" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 10-Year Rainfall=4.60" Area (sf) CN Description 0 61 >75% Grass cover, Good, HSG B 3,325 98 Paved parking, HSG B 2,550 98 Roofs, HSG B 5,875 Weighted Average 0 61 0.00% Pervious Area 5,875 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PS-1A: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Type III 24-hr 10-Year Rainfall=4.60" Runoff Area=5,875 sf Runoff Volume=2,137 cf Runoff Depth=4.36" Tc=6.0 min CN=WQ 0.60 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 12HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1B: Runoff = 0.53 cfs @ 12.17 hrs, Volume= 2,287 cf, Depth= 1.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 10-Year Rainfall=4.60" Area (sf) CN Description 13,854 61 >75% Grass cover, Good, HSG B 248 96 Gravel surface, HSG B 345 98 Paved parking, HSG B 1,411 98 Roofs, HSG B 692 98 Water Surface, HSG B 16,550 Weighted Average 14,102 62 85.21% Pervious Area 2,448 98 14.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 143 0.0280 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.0 9 0.3330 9.29 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 11.8 152 Total Subcatchment PS-1B: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)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=4.60" Runoff Area=16,550 sf Runoff Volume=2,287 cf Runoff Depth=1.66" Flow Length=152' Tc=11.8 min CN=WQ 0.53 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 13HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-2: Subcat ES-2 Runoff = 0.25 cfs @ 12.19 hrs, Volume= 1,147 cf, Depth= 2.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 10-Year Rainfall=4.60" Area (sf) CN Description 4,166 61 >75% Grass cover, Good, HSG B 2,070 98 Paved parking, HSG B 6,236 Weighted Average 4,166 61 66.81% Pervious Area 2,070 98 33.19% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 125 0.0220 0.18 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 2.0 119 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 13.6 244 Total Subcatchment PS-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 10-Year Rainfall=4.60" Runoff Area=6,236 sf Runoff Volume=1,147 cf Runoff Depth=2.21" Flow Length=244' Tc=13.6 min CN=WQ 0.25 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 14HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Pond 1P: Bioretention Area Inflow Area = 5,875 sf,100.00% Impervious, Inflow Depth = 4.36" for 10-Year event Inflow = 0.60 cfs @ 12.08 hrs, Volume= 2,137 cf Outflow = 0.03 cfs @ 14.56 hrs, Volume= 2,137 cf, Atten= 95%, Lag= 148.3 min Discarded = 0.03 cfs @ 14.56 hrs, Volume= 2,137 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 130.23' @ 14.56 hrs Surf.Area= 1,154 sf Storage= 1,126 cf Plug-Flow detention time= 405.8 min calculated for 2,135 cf (100% of inflow) Center-of-Mass det. time= 405.9 min ( 1,155.3 - 749.4 ) Volume Invert Avail.Storage Storage Description #1 129.00' 4,061 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 129.00 692 123.0 0 0 692 130.00 1,062 133.0 870 870 933 131.00 1,490 152.0 1,270 2,140 1,386 132.00 2,387 251.0 1,921 4,061 4,568 Device Routing Invert Outlet Devices #1 Discarded 129.00'1.020 in/hr Exfiltration over Surface area #2 Primary 123.41'16.0" Round Culvert L= 10.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 123.41' / 123.31' S= 0.0100 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.40 sf #3 Device 2 130.66'8.0" Horiz. OCS-1 X 0.75 C= 0.600 Limited to weir flow at low heads #4 Device 2 131.62'24.0" x 24.0" Horiz. Existing Catch Basin C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.03 cfs @ 14.56 hrs HW=130.23' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=129.00' (Free Discharge) 2=Culvert (Passes 0.00 cfs of 11.78 cfs potential flow) 3=OCS-1 ( Controls 0.00 cfs) 4=Existing Catch Basin ( Controls 0.00 cfs) 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 15HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Pond 1P: Bioretention Area Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=5,875 sf Peak Elev=130.23' Storage=1,126 cf 0.60 cfs 0.03 cfs 0.03 cfs 0.00 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 16HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 22,425 sf, 37.12% Impervious, Inflow Depth = 1.22" for 10-Year event Inflow = 0.53 cfs @ 12.17 hrs, Volume= 2,287 cf Primary = 0.53 cfs @ 12.17 hrs, Volume= 2,287 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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=22,425 sf 0.53 cfs 0.53 cfs 210226 - POST Type III 24-hr 10-Year Rainfall=4.60"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 17HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 6,236 sf, 33.19% Impervious, Inflow Depth = 2.21" for 10-Year event Inflow = 0.25 cfs @ 12.19 hrs, Volume= 1,147 cf Primary = 0.25 cfs @ 12.19 hrs, Volume= 1,147 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)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=6,236 sf 0.25 cfs 0.25 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 18HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=5,875 sf 100.00% Impervious Runoff Depth=6.26"Subcatchment PS-1A: Tc=6.0 min CN=WQ Runoff=0.85 cfs 3,066 cf Runoff Area=16,550 sf 14.79% Impervious Runoff Depth=2.98"Subcatchment PS-1B: Flow Length=152' Tc=11.8 min CN=WQ Runoff=1.02 cfs 4,112 cf Runoff Area=6,236 sf 33.19% Impervious Runoff Depth=3.65"Subcatchment PS-2: Subcat ES-2 Flow Length=244' Tc=13.6 min CN=WQ Runoff=0.44 cfs 1,895 cf Peak Elev=130.68' Storage=1,691 cf Inflow=0.85 cfs 3,066 cfPond 1P: Bioretention Area Discarded=0.03 cfs 2,966 cf Primary=0.02 cfs 100 cf Outflow=0.05 cfs 3,066 cf Inflow=1.02 cfs 4,212 cfLink DP-1: On Site Low Point Primary=1.02 cfs 4,212 cf Inflow=0.44 cfs 1,895 cfLink DP-2: Offsite to West/Southwest & Sherman Ave Primary=0.44 cfs 1,895 cf Total Runoff Area = 28,661 sf Runoff Volume = 9,072 cf Average Runoff Depth = 3.80" 63.74% Pervious = 18,268 sf 36.26% Impervious = 10,393 sf 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 19HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1A: Runoff = 0.85 cfs @ 12.08 hrs, Volume= 3,066 cf, Depth= 6.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 0 61 >75% Grass cover, Good, HSG B 3,325 98 Paved parking, HSG B 2,550 98 Roofs, HSG B 5,875 Weighted Average 0 61 0.00% Pervious Area 5,875 98 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment PS-1A: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 100-Year Rainfall=6.50" Runoff Area=5,875 sf Runoff Volume=3,066 cf Runoff Depth=6.26" Tc=6.0 min CN=WQ 0.85 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 20HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-1B: Runoff = 1.02 cfs @ 12.17 hrs, Volume= 4,112 cf, Depth= 2.98" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 13,854 61 >75% Grass cover, Good, HSG B 248 96 Gravel surface, HSG B 345 98 Paved parking, HSG B 1,411 98 Roofs, HSG B 692 98 Water Surface, HSG B 16,550 Weighted Average 14,102 62 85.21% Pervious Area 2,448 98 14.79% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 143 0.0280 0.20 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 0.0 9 0.3330 9.29 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 11.8 152 Total Subcatchment PS-1B: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 100-Year Rainfall=6.50" Runoff Area=16,550 sf Runoff Volume=4,112 cf Runoff Depth=2.98" Flow Length=152' Tc=11.8 min CN=WQ 1.02 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 21HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PS-2: Subcat ES-2 Runoff = 0.44 cfs @ 12.19 hrs, Volume= 1,895 cf, Depth= 3.65" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 4,166 61 >75% Grass cover, Good, HSG B 2,070 98 Paved parking, HSG B 6,236 Weighted Average 4,166 61 66.81% Pervious Area 2,070 98 33.19% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.6 125 0.0220 0.18 Sheet Flow, Grass: Short n= 0.150 P2= 3.00" 2.0 119 0.0025 1.02 Shallow Concentrated Flow, Paved Kv= 20.3 fps 13.6 244 Total Subcatchment PS-2: Subcat ES-2 Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 100-Year Rainfall=6.50" Runoff Area=6,236 sf Runoff Volume=1,895 cf Runoff Depth=3.65" Flow Length=244' Tc=13.6 min CN=WQ 0.44 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 22HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Pond 1P: Bioretention Area Inflow Area = 5,875 sf,100.00% Impervious, Inflow Depth = 6.26" for 100-Year event Inflow = 0.85 cfs @ 12.08 hrs, Volume= 3,066 cf Outflow = 0.05 cfs @ 13.72 hrs, Volume= 3,066 cf, Atten= 94%, Lag= 98.4 min Discarded = 0.03 cfs @ 13.72 hrs, Volume= 2,966 cf Primary = 0.02 cfs @ 13.72 hrs, Volume= 100 cf Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 130.68' @ 13.72 hrs Surf.Area= 1,347 sf Storage= 1,691 cf Plug-Flow detention time= 521.4 min calculated for 3,064 cf (100% of inflow) Center-of-Mass det. time= 521.7 min ( 1,265.6 - 744.0 ) Volume Invert Avail.Storage Storage Description #1 129.00' 4,061 cf Custom Stage Data (Irregular) Listed below (Recalc) Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 129.00 692 123.0 0 0 692 130.00 1,062 133.0 870 870 933 131.00 1,490 152.0 1,270 2,140 1,386 132.00 2,387 251.0 1,921 4,061 4,568 Device Routing Invert Outlet Devices #1 Discarded 129.00'1.020 in/hr Exfiltration over Surface area #2 Primary 123.41'16.0" Round Culvert L= 10.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 123.41' / 123.31' S= 0.0100 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.40 sf #3 Device 2 130.66'8.0" Horiz. OCS-1 X 0.75 C= 0.600 Limited to weir flow at low heads #4 Device 2 131.62'24.0" x 24.0" Horiz. Existing Catch Basin C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.03 cfs @ 13.72 hrs HW=130.68' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.02 cfs @ 13.72 hrs HW=130.68' (Free Discharge) 2=Culvert (Passes 0.02 cfs of 13.64 cfs potential flow) 3=OCS-1 (Weir Controls 0.02 cfs @ 0.37 fps) 4=Existing Catch Basin ( Controls 0.00 cfs) 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 23HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Pond 1P: Bioretention Area Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (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 Inflow Area=5,875 sf Peak Elev=130.68' Storage=1,691 cf 0.85 cfs 0.05 cfs 0.03 cfs 0.02 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 24HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-1: On Site Low Point Inflow Area = 22,425 sf, 37.12% Impervious, Inflow Depth = 2.25" for 100-Year event Inflow = 1.02 cfs @ 12.17 hrs, Volume= 4,212 cf Primary = 1.02 cfs @ 12.17 hrs, Volume= 4,212 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-1: On Site Low Point Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=22,425 sf 1.02 cfs 1.02 cfs 210226 - POST Type III 24-hr 100-Year Rainfall=6.50"210226 - POST_2 Printed 9/14/2021Prepared by {enter your company name here} Page 25HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Area = 6,236 sf, 33.19% Impervious, Inflow Depth = 3.65" for 100-Year event Inflow = 0.44 cfs @ 12.19 hrs, Volume= 1,895 cf Primary = 0.44 cfs @ 12.19 hrs, Volume= 1,895 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link DP-2: Offsite to West/Southwest & Sherman Ave Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=6,236 sf 0.44 cfs 0.44 cfs PWQU-1ROOF Routing Diagram for 210226 - INLET Prepared by {enter your company name here}, Printed 7/27/2021 HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Subcat Reach Pond Link 210226 - INLET Type III 24-hr 100-Year Rainfall=6.50"210226 - INLET Printed 7/27/2021Prepared by {enter your company name here} Page 8HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-Q Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=5,898 sf 100.00% Impervious Runoff Depth=6.26"Subcatchment PWQU-1: Tc=0.0 min CN=WQ Runoff=1.02 cfs 3,078 cf Runoff Area=1,728 sf 100.00% Impervious Runoff Depth=6.26"Subcatchment ROOF: Tc=0.0 min CN=98 Runoff=0.30 cfs 902 cf Total Runoff Area = 7,626 sf Runoff Volume = 3,979 cf Average Runoff Depth = 6.26" 0.00% Pervious = 0 sf 100.00% Impervious = 7,626 sf 210226 - INLET Type III 24-hr 100-Year Rainfall=6.50"210226 - INLET Printed 7/27/2021Prepared by {enter your company name here} Page 9HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment PWQU-1: Runoff = 1.02 cfs @ 12.00 hrs, Volume= 3,078 cf, Depth= 6.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 0 61 >75% Grass cover, Good, HSG B 4,560 98 Paved parking, HSG B 1,338 98 Roofs, HSG B 5,898 Weighted Average 0 61 0.00% Pervious Area 5,898 98 100.00% Impervious Area Subcatchment PWQU-1: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type III 24-hr 100-Year Rainfall=6.50" Runoff Area=5,898 sf Runoff Volume=3,078 cf Runoff Depth=6.26" Tc=0.0 min CN=WQ 1.02 cfs 210226 - INLET Type III 24-hr 100-Year Rainfall=6.50"210226 - INLET Printed 7/27/2021Prepared by {enter your company name here} Page 10HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Summary for Subcatchment ROOF: Runoff = 0.30 cfs @ 12.00 hrs, Volume= 902 cf, Depth= 6.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-Q, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type III 24-hr 100-Year Rainfall=6.50" Area (sf) CN Description 1,728 98 Roofs, HSG B 1,728 98 100.00% Impervious Area Subcatchment ROOF: Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 100-Year Rainfall=6.50" Runoff Area=1,728 sf Runoff Volume=902 cf Runoff Depth=6.26" Tc=0.0 min CN=98 0.30 cfs 9,217 SF 9,701 SF 484 SF 5,875 SF Total New Impervious Area Total Existing Impervious Area Total Proposed Impervious Area Total Impervious Area Tributary to Recharge Facilities ½ Type III 24-hr 100-Year Rainfall=6.50"210226 - POST Printed 7/26/2021Prepared by {enter your company name here} HydroCAD® 10.00-25 s/n 02175 © 2019 HydroCAD Software Solutions LLC Stage-Area-Storage for Pond 1P: Bioretention Area Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 129.00 692 0 129.05 708 35 129.10 725 71 129.15 742 108 129.20 759 145 129.25 776 183 129.30 793 223 129.35 811 263 129.40 828 304 129.45 846 346 129.50 864 388 129.55 883 432 129.60 901 477 129.65 920 522 129.70 939 569 129.75 958 616 129.80 977 664 129.85 997 714 129.90 1,016 764 129.95 1,036 815 130.00 1,056 868 130.05 1,075 921 130.10 1,095 975 130.15 1,115 1,030 130.20 1,135 1,087 130.25 1,155 1,144 130.30 1,175 1,202 130.35 1,195 1,261 130.40 1,216 1,322 130.45 1,237 1,383 130.50 1,258 1,445 130.55 1,279 1,509 130.60 1,300 1,573 130.65 1,322 1,639 130.70 1,343 1,705 130.75 1,365 1,773 130.80 1,387 1,842 130.85 1,409 1,912 130.90 1,432 1,983 130.95 1,454 2,055 131.00 1,477 2,128 131.05 1,515 2,203 131.10 1,554 2,280 131.15 1,594 2,358 131.20 1,633 2,439 131.25 1,674 2,522 131.30 1,715 2,607 131.35 1,756 2,693 131.40 1,798 2,782 131.45 1,840 2,873 131.50 1,883 2,966 131.55 1,926 3,061 Elevation (feet) Surface (sq-ft) Storage (cubic-feet) 131.60 1,970 3,159 131.65 2,014 3,258 131.70 2,059 3,360 131.75 2,104 3,464 131.80 2,150 3,571 131.85 2,196 3,679 131.90 2,243 3,790 131.95 2,290 3,904 132.00 2,338 4,019 MassDEP Q Rate - Sept. 10, 2013 - Page 4 Figure 2: For First ½-inch of Runoff, Table of qu values for Ia/P Curve = 0.0.058, listed by tc, for Type III Storm Distribution Tc qu Tc qu Tc qu Tc qu (Hours) (csm/in) (Hours) (csm/in) (Hours) (csm/in) (Hours) (csm/in) 0.01 821 1.8 246 5.3 116 8.8 77 0.03 821 1.9 238 5.4 115 8.9 76 0.05 813 2 230 5.5 113 9 76 0.067 794 2.1 223 5.6 112 9.1 75 0.083 773 2.2 217 5.7 110 9.2 74 0.1 752 2.3 211 5.8 109 9.3 74 0.116 733 2.4 205 5.9 107 9.4 73 0.133 713 2.5 200 6 106 9.5 72 0.15 694 2.6 194 6.1 104 9.6 72 0.167 677 2.7 190 6.2 103 9.7 71 0.183 662 2.8 185 6.3 102 9.8 70 0.2 646 2.9 181 6.4 100 9.9 70 0.217 632 3 176 6.5 99 10 69 0.233 619 3.1 173 6.6 98 0.25 606 3.2 169 6.7 97 0.3 572 3.3 165 6.8 96 0.333 552 3.4 162 6.9 94 0.35 542 3.5 158 7 93 0.4 516 3.6 155 7.1 92 0.416 508 3.7 152 7.2 91 0.5 472 3.8 149 7.3 90 0.583 443 3.9 147 7.4 89 0.6 437 4 144 7.5 88 0.667 417 4.1 141 7.6 87 0.7 408 4.2 139 7.7 86 0.8 383 4.3 136 7.8 85 0.9 361 4.4 134 7.9 84 1 342 4.5 132 8 84 1.1 325 4.6 130 8.1 83 1.2 311 4.7 128 8.2 82 1.3 297 4.8 126 8.3 81 1.4 285 4.9 124 8.4 80 1.5 274 5 122 8.5 79 1.6 264 5.1 120 8.6 79 1.7 254 5.2 118 8.7 78 SHEET OFDATE:PROJECT #:DRAWN:CHECKED:THIS DRAWING HAS BEEN PREPARED BASED ON INFORMATION PROVIDED TO ADS UNDER THE DIRECTION OF THE SITE DESIGN ENGINEER OR OTHER PROJECT REPRESENTATIVE. THE SITE DESIGN ENGINEER SHALL REVIEW THIS DRAWING PRIOR TO CONSTRUCTION. IT IS THE ULTIMATERESPONSIBILITY OF THE SITE DESIGN ENGINEER TO ENSURE THAT THE PRODUCT(S) DEPICTED AND ALL ASSOCIATED DETAILS MEET ALL APPLICABLE LAWS, REGULATIONS, AND PROJECT REQUIREMENTS.4640 TRUEMAN BLVDHILLIARD, OH 43026ADVANCED DRAINAGE SYSTEMS, INC.R1 13/22/19 EKH----STANDARD DETAILREVDWNCKDDESCRIPTIONBARRACUDA S3NOT TO SCALE1030 Deer Hollow DriveMount Airy, MD 217711-800-BAYSAVER1-800-229-72831030 Deer Hollow DriveMount Airy, MD 217711-800-BAYSAVER1-800-229-728336" CONCRETE MANHOLE ----" FRAME & COVER ----" OUTLET PIPE ----" INLET PIPE PLAN VIEW NTS INTEGRATED INTERNAL WEIR FIN ARRAY (TYP 4 PLACES) 95.00 SUMP 100.00 INLET 103.00 RIM 100.00 OUTLET SECTION VIEW A-A NTS ASPHALT INSTALLATION ----" FRAME & COVER TURF INSTALLATION 36.0" (36.0" MIN) 60" ----" INLET PIPE (----" OUTLET PIPE NOT SHOWN FOR CLARITY ) BOWL FIN ARRAY (TYP 4 PLACES) SECTION VIEW B-B NTS 12" (MIN) BARRACUDA S3 UNIT ID PEAK FLOW RATE TREATMENT FLOW RATE (CFS) (CFS) 8.00' [96.00"] FIN ARRAY (TYP 4 PLACES) BOWL INTEGRATED INTERNAL WEIR INTEGRATED INTERNAL WEIR 7.00± VARIABLE OUTLET LOCATIONS VARIABLE INLET LOCATIONS 1 KIM GUADAGNO Lt. Governor September 18, 2017 Daniel J. Figola, P.E. General Manager BaySaver Technologies, LLC 1030 Deer Hollow Drive Mt. Airy, MD 21771 Re: MTD Lab Certification BaySaver BarracudaTM Hydrodynamic Separator by BaySaver Technologies, LLC Online Installation TSS Removal Rate 50% Dear Mr. Figola: The Stormwater Management rules under N.J.A.C. 7:8-5.5(b) and 5.7 (c) allow the use of manufactured treatment devices (MTDs) for compliance with the design and performance standards at N.J.A.C. 7:8-5 if the pollutant removal rates have been verified by the New Jersey Corporation for Advanced Technology (NJCAT) and have been certified by the New Jersey Department of Environmental Protection (NJDEP). BaySaver Technologies, LLC has requested an MTD Laboratory Certification for the BaySaver BarracudaTM Hydrodynamic Separator (BaySaver Barracuda). The project falls under the “Procedure for Obtaining Verification of a Stormwater Manufactured Treatment Device from New Jersey Corporation for Advance Technology” dated January 25, 2013. The applicable protocol is the “New Jersey Laboratory Testing Protocol to Assess Total Suspended Solids Removal by a Hydrodynamic Sedimentation Manufactured Treatment Device” dated January 25, 2013. NJCAT verification documents submitted to the NJDEP indicate that the requirements of the aforementioned protocol have been met or exceeded. The NJCAT letter also included a recommended certification TSS removal rate and the required maintenance plan. The NJCAT Verification Report with the Verification Appendix (dated September 2017) for this device is published online at http://www.njcat.org/verification-process/technology-verification-database.html. DEPARTMENT OF ENVIRONMENTAL PROTECTION CHRIS CHRISTIE BOB MARTIN Governor Commissioner New Jersey is an Equal Opportunity Employer Printed on Recycled Paper and Recyclable Bureau of Nonpoint Pollution Control Division of Water Quality 401-02B Post Office Box 420 Trenton, New Jersey 08625-0420 609-633-7021 Fax: 609-777-0432 http://www.state.nj.us/dep/dwq/bnpc_home.htm 2 The NJDEP certifies the use of the BaySaver Barracuda by BaySaver Technologies, LLC at a TSS removal rate of 50% when designed, operated, and maintained in accordance with the information provided in the Verification Appendix and the following conditions: 1. The maximum treatment flow rate (MTFR) for the manufactured treatment device (MTD) is calculated using the New Jersey Water Quality Design Storm (1.25 inches in 2 hrs) in N.J.A.C. 7:8-5.5. 2. The BaySaver Barracuda shall be installed using the same configuration reviewed by NJCAT and shall be sized in accordance with the criteria specified in item 6 below. 3. This BaySaver Barracuda cannot be used in series with another MTD or a media filter (such as a sand filter) to achieve an enhanced removal rate for total suspended solids (TSS) removal under N.J.A.C. 7:8-5.5. 4. Additional design criteria for MTDs can be found in Chapter 9.6 of the New Jersey Stormwater Best Management Practices (NJ Stormwater BMP) Manual, which can be found online at www.njstormwater.org. 5. The maintenance plan for a site using this device shall incorporate, at a minimum, the maintenance requirements for the BaySaver Barracuda. A copy of the maintenance plan is attached to this certification. However, it is recommended to review the maintenance website at http://www.ads-pipe.com/pdf/en/Barracuda_Maintenance_07_17.pdf for any changes to the maintenance requirements. 6. Sizing Requirement: The example below demonstrates the sizing procedure for the BaySaver Barracuda: Example: A 0.25-acre impervious site is to be treated to 50% TSS removal using a BaySaver Barracuda. The impervious site runoff (Q) based on the New Jersey Water Quality Design Storm was determined to be 0.79 cfs. Maximum Treatment Flow Rate (MTFR) Evaluation: The site runoff (Q) was based on the following: time of concentration = 10 minutes i = 3.2 in/hr (page 5-8, Fig. 5-3 of the NJ Stormwater BMP Manual) c = 0.99 (curve number for impervious) Q = ciA = 0.99 x 3.2 x 0.25 = 0.79 cfs Given the site runoff is 0.79 cfs and based on Table 1 below, the Barracuda Model S4 with a MTFR of 1.25 cfs could be used for this site to remove 50% of the TSS from the impervious area without exceeding the MTFR. The sizing table corresponding to the available system models is noted below. Additional specifications regarding each model can be found in the Verification Appendix under Table A-1. 3 Table 1 BaySaver Barracuda Sizing Information Barracuda Model NJDEP 50% TSS Maximum Treatment Flow Rate (cfs) Treatment Area (ft2) Hydraulic Loading Rate (gpm/ft2) 50% Maximum Sediment Storage (ft3) S3 0.70 7.07 44.6 5.89 S4 1.25 12.57 44.6 10.47 S5 1.95 19.63 44.6 16.36 S6 2.80 28.27 44.6 23.56 S8 5.00 50.27 44.6 41.89 S10 7.80 78.54 44.6 65.45 A detailed maintenance plan is mandatory for any project with a Stormwate r BMP subject to the Stormwater Management Rules, N.J.A.C. 7:8. The plan must include all of the items identified in the Stormwater Management Rules, N.J.A.C. 7:8-5.8. Such items include, but are not limited to, the list of inspection and maintenance equipment and tools, specific corrective and preventative maintenance tasks, indication of problems in the system, and training of maintenance personnel. Additional information can be found in Chapter 8: Maintenance and Retrofit of Stormwater Management Measures. If you have any questions regarding the above information, please contact Mr. Shashi Nayak of my office at (609) 633-7021. Sincerely, James J. Murphy, Chief Bureau of Nonpoint Pollution Control Attachment: Maintenance Plan cc: Chron File Richard Magee, NJCAT Vince Mazzei, NJDEP - DLUR Ravi Patraju, NJDEP - BES Gabriel Mahon, NJDEP - BNPC Shashi Nayak, NJDEP - BNPC 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 1 MG1.01 ©ADS 2017 One of the advantages of the BaySaver Barracuda is the ease of maintenance. Like any system that collects pollutants, the BaySaver Barracuda must be maintained for continued effectiveness. Maintenance is a simple procedure performed using a vacuum truck or similar equipment. The systems were designed to minimize the volume of water removed during routine maintenance, reducing disposal costs. Contractors can access the pollutants stored in the manhole through the manhole cover. This allows them to gain vacuum hose access to the bottom of the manhole to remove sediment and trash. There is no confined space entry necessary for inspection or maintenance. The entire maintenance procedure typically takes from 2 to 4 hours, depending on the size of the system, the captured material, and the capacity of the vacuum truck. Local regulations may apply to the maintenance procedure. Safe an d legal disposal of pollutants is the responsibility of the maintenance contractor. Maintenance should be performed only by a qualified contractor. Inspection and Cleaning Cycle Periodic inspection is needed to determine the need for and frequency of maint enance. You should begin inspecting as soon as construction is complete and thereafter on an annual basis. Typically, the system needs to be cleaned every 1-3 years. Excessive oils, fuels or sediments may reduce the maintenance cycle. Periodic inspection is important. Determining When to Clean To determine the sediment depth, the maintenance contractor should lower a stadia rod into the manhole until it contacts the top of the captured sediment and mark that spot on the rod. Then push the probe through to the bottom of the sump and mark that spot to determine sediment depth. Maintenance should occur when the sediment has reached the levels indicated in the Storage Capacity Chart. BaySaver Barracuda Storage Capacities Model Manhole Diameter Treatment Chamber Capacity Standard Sediment Capacity (20” depth) NJDEP Sediment Capacity (50% of standard depth) S3 36” 212 gallons 0.44 cubic yards 0.22 cubic yards S4 48” 564 gallons 0.78 cubic yards 0.39 cubic yards S5 60” 881 gallons 1.21 cubic yards 0.61 cubic yards S6 72” 1269 gallons 1.75 cubic yards 0.88 cubic yards S8 96” 3835 gallons 3.10 cubic yards 1.55 cubic yards S10 120” 7496 gallons 4.85 cubic yards 2.43 cubic yards Maintenance Instructions 1. Remove the manhole cover to provide access to the pollutant storage. Pollutants are stored in the sump, below the bowl assembly visible from the surface. You’ll access this area through the 10” diameter access cylinder. Maintenance Guide BaySaver Barracuda July 2017 2 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com MG1.01 ©ADS 2017 2. Use a vacuum truck or other similar equipment to remove all water, debris, oils and sediment. See figure 1. 3. Use a high pressure hose to clean the manhole of all the remaining sediment and debris. Then, use the vacuum truck to remove the water. 4. Fill the cleaned manhole with water until the level reaches the invert of the outlet pipe. 5. Replace the manhole cover. 6. Dispose of the polluted water, oils, sediment and trash at an approved facility. • Local regulations prohibit the discharge of solid material into the sanitary system. Check with the local sewer authority for authority to discharge the liquid. • Some localities treat the pollutants as leachate. Check with local regulators about disposal requirements. • Additional local regulations may apply to the maintenance procedure. Figure 1 Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 1 The project shall implement a construction period erosion control plan. The following provides descriptions and guidelines to ensure that the areas surrounding the project site will be protected from excessive sedimentation and runoff during construction. 1.1 Construction Period Pollution Prevention And Erosion Control Measures 1.1.1 Preconstruction Notifications And Meetings Prior to the start of construction, the contractor shall call together a pre-construction meeting including a representative from the City, the design engineer, contractor, and any pertinent persons that should be in attendance. These requirements shall be the responsibility of the Contractor to arrange, attend, and document. 1.1.2 Sediment Barrier And Work Limit Before installation of the sediment barriers, the location shall be staked in the field for review and approval by the owner or their representative. To facilitate sediment barrier installation, woody vegetation may then be removed and any required trench may be cut by machine, provided all other ground cover is left intact. No excavation, grading, filling, or removal of vegetative ground cover shall begin until sediment barriers have been installed as shown on the plans and have been inspected by the owner or their representative. 1.1.3 Silt Fence The bottom of the fence shall be trenched into the ground a minimum of 6" and back-filled with compacted soil. Where trenching is not feasible, silt fence skirt shall be covered with compacted soil or crushed stone. The top of the fabric shall be stretched as tightly as is practical, with intermediate stakes added to correct excessive sags. Stakes shall be driven at least 12" into the ground. Splices between sections shall be made by rolling end stakes together one complete turn and driving into the ground together. 1.1.4 Straw Bales Straw bales may be used as temporary and moveable control measures, temporary check dams, or as reinforcement for silt fence in areas of concentrated runoff or high fills. Bales shall be tightly butted and staked 12" into the ground. Where used without silt fence in front, the bales shall be trenched 4" into the ground, back-filled with compacted soil, and the spaces between bales shall be chinked with loose hay. 1.1.5 Filter Sock (Filtrexx Or Equivalent) In areas of expected sheet flow, filter sock may be placed directly on the ground without trenching or stakes. In areas of expected concentrated flow, mulch or crushed stone shall be placed along the up-slope face to control and filter underflow. Additional layers of Filter Sock may be required for adequate freeboard. The filter sock shall be staked at 10 feet on-center or in cases where they cannot be staked, utilize heavy concrete blocks to hold in place. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 2 1.1.6 Temporary Sedimentation Basins Temporary sediment basins may be excavations or bermed stormwater detention structu res (depending on grading) that will retain runoff for a sufficient period of time to allow suspended soil particles to settle out prior to discharge. These temporary basins will be located based on construction needs as determined by the contractor and outlet devices will be designed to control velocity and sediment. Points of discharge from sediment basins will be stabilized to minimize erosion. If the temporary basin is to be located within an area of future infiltration as part of the stormwater management system, the excavation for the temporary sedimentation basin shall be limited to one foot above final grade of the infiltration structure. 1.1.7 Stocking Additional Materials A stock of additional erosion control materials shall be available on the site for emergency repairs and temporary measures. Stock shall be replenished when decreased to 50% of the numbers below. Stock shall include: Straw Bales – 10 (kept dry) with 20 oak stakes Or Silt Fence – 30 Linear feet. Or Filter Sock – 4 – 8 foot sections (kept dry) Washed Stone – One (1) cubic yard, ¾” to 2” diameter 1.1.8 Trench Protection Open trenches shall be protected from accumulation of surface water or groundwater that could result in erosion of the trench and discharge of sediment. Where feasible, spoil shall be stockpiled on the up-slope side of the trench to prevent entrance of surface runoff. Backfill shall be crowned to allow for settlement and to avoid concentration of runoff on top of the trench. 1.1.9 Site Stabilization – Temporary Where a portion of the site will not be subject to construction activity for over 14 days, measures shall be taken to provide temporary stabilization of that inactive portion of the site, within 14 days of the cessation of construction activity. Stabilization measures may include seeding for temporary cover, mulching, or other measures to protect exposed soil from erosion and prevent sediment movement. 1.1.10 Site Stabilization – Permanent Within 14 days of completion of loaming and finish grading on any portion of the site, that area shall be seeded or planted for permanent cover (season permitting) in accordance with USDA NRCS guidelines or equivalent. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 3 1.1.11 Roadway Sweeping The entrance to the site and affected portions of the access drive or paved project areas shall be swept as needed to control sediment runoff into storm drains or waterways and to control blowing dust. 1.2 Short-Term Erosion Control Maintenance The following provides short-term erosion control maintenance guidelines and requirements. 1. The contractor or subcontractor will be responsible for implementing each control shown on the sedimentation and erosion control plan. 2. All erosion and sediment control devices shall be properly maintained during all phases of construction until the completion of all construction activities and all disturbed areas have been stabilized. Additional control measures will be installed during construction in order to control erosion and/or off-site sedimentation if deemed necessary by on-site inspection. 3. Effective erosion control measures shall be initiated prior to the commencement of clearing, grading, excavation, or other operations that will disturb the natural protection. 4. All sediment and erosion control devices shall be inspected at least once every seven (7) calendar days and after any storm event greater than 0.5 inches of precipitation during any 24-hour period, and the inspection shall be documented in writing. Damaged or ineffective devices shall be repaired or replaced, as necessary. 5. The contractor shall take all reasonable precautions to avoid excess erosion of the site due to the construction of this project. 6. Silt shall be removed from behind barriers if greater than 6-inches deep or as needed. Sediment that is collected in structures shall be disposed of properly and covered if stored on-site 7. Damaged or deteriorated items will be repaired immediately after identification. 8. All ditches shall be stabilized as soon as is practicable to minimize erosion. 9. The contractor shall maintain all erosion control devices in a good, working state of repair. Upon complete stabilization of any tributary areas, the erosion control devices shall be removed and disposed of so as to cause no off-site siltation. 10. Inspect and maintain construction entrance stone such that sediment does not track onto the street. Any sediment tracked onto the street shall be swept daily. 11. After catch basins have been constructed, the contractor shall protect the inlets by constructing inlet protection as shown on the plans. 12. Once the site has been paved, all catch basin inlets shall receive a silt sack type protection. 13. Erosion control measures shall remain in place until all disturbed earth has been substantially stabilized. After removal of structures, disturbed areas shall be regraded and stabilized as necessary. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Appendix G: Long-Term Operation and Maintenance Plan - Long-Term Operation & Maintenance Plan Narrative - Barracuda Installation Guide - Barracuda Maintenance Guide - O&M Checklist Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 2 2. Inspection and Maintenance Program: Regular inspection and routine maintenance are necessary to ensure that the stormwater management system continues to control and treat runoff. The following lists the inspection schedule and maintenance procedures for the proposed stormwater Best Management Practices: BMP Inspection Schedule Maintenance Schedule Maintenance Procedures Bituminous Concrete Pavement Four times per year Twice per year • Roadway to be swept in March or April following snow melt and again in late November or early December to remove fallen leaves and debris Bio-Retention Areas Once per month Twice per year (Spring and Fall) • Inspect bio-retention areas for sediment build- up, structural damage, and standing water; • Inspect and repair eroded areas monthly; • Re-mulch void areas as needed; • Remove litter and debris monthly; • Treat diseased or distressed vegetation as needed; • Remove and replace dead vegetation twice per year (Spring and Fall); • Remove invasive species as needed; • Replace mulch every two years. Stormwater Piping Once per year Once per year • Inspect pipe entrances in catch basins and manholes and remove any blockages Roof Leaders Once per year Once per year • Inspect downspout connections at grade and remove any blockages • Open and inspect cleanout locations and remove any blockages Barracuda Water Quality Unit* As specified by the manufacturer As specified by the manufacturer • Clean the unit using the method specified by the manufacturer. Vactor trucks are typically used to clean these units. *See attached Device Operation and Maintenance Guides See the attached Long-Term O&M Inspection Checklist for record keeping purposes. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 3 3. Additional Long-Term Operation and Maintenance Items The following is a list of additional operation and maintenance items to be implemented by the owner/governing group to maintain the features proposed in this project. A. Proper storage, use, and disposal of hazardous chemicals, including automobile fluids, pesticides, paints, solvents, etc. shall be required. Information should be provided on chemicals of concern, proper use, and disposal options. Recycling programs for used motor oil, antifreeze, and other products should be developed. B. Vehicle Washing. This management measure involves educating the owner on the water quality impacts of the outdoor washing of vehicles and how to avoid allowing polluted runoff to enter the storm drain system. Outdoor vehicle washing has the potential to result in high loads of nutrients, metals, and hydrocarbons which is conveyed by the detergent-rich water into storm drains. C. Recycling, spill prevention and response plans, and proper material storage and disposal of potentially hazardous materials shall be implemented. It will be the responsibility of the owner to contain and legally remove any materials that are spilled onsite. The use of dry floor cleaners and absorbent materials and limiting the use of water to clean pavement is encouraged. Care should be taken to avoid accidental disposal of hazardous materials. D. Provisions for storing trash and waste products shall be implemented. The waste materials shall be collected by the owner and all materials shall be properly disposed of. E. Requirements for routine inspections and maintenance of stormwater best management practices. Routine inspections shall be performed to ensure the correct functioning of stormwater best management practices. See the specific maintenance criteria for detail regarding inspections and maintenance frequency. F. Requirements for Storage and Use of Fertilizers, Herbicides, and Pesticides. Fertilizers, pesticides, herbicides, lawn care chemicals, or other leachable materials shall be used in accordance with the Lawn Care Regulations of the Massachusetts Pesticide Board, 33 CMR 10.03 (30,31), as amended, with manufacturer’s label instructions and all other necessary precautions to minimize adverse impacts on surface and groundwater. The storage of any such materials shall be within structure designed to prevent the escape of contaminat ed runoff or leachate. G. Provisions for prevention of illicit discharges to the stormwater management system shall be implemented. Any illicit discharges to the stormwater management system shall be prohibited. It will be the owner’s responsibility to ensure compliance with the legal disposal of all materials and containment/cleanup of any illicit discharges. H. Training for staff or personnel involved with implementation of the Long-Term Pollution Prevention Plan shall be required. The owner/governing group will be responsible for the implementation of the measures set forth in the Long-Term Pollution Prevention Plan. Documentation that personnel and owners involved with the implementation of the Long-Term Pollution Prevention Plan have been trained to conduct such tasks shall be documented. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 4 4. Winter and Snow Conditions The following is a list of additional operation and maintenance items to be implemented by the owner during winter and snow conditions. A. Snowfall shall be stored on the grassed areas surrounding the pavement areas, excluding any areas utilized for stormwater management practices. As needed, any snow that cannot be stored on site shall be trucked off site and disposed of properly. B. Winter road salt and/or sand use and storage restrictions shall be implemented based on any restrictions issued for the project. Sodium chloride for ice control shall be used at the minimum salt to sand ratio which is consistent with the Massachusetts Department of Environmental Protections guidelines. Sodium chloride, calcium chloride, chemically treated abrasives or other chemicals used for the removal of ice and snow on roads/drives shall not be stored on site. 5. Public Safety Features The proposed site design utilizes the following features which have been incorporated to ensure the safety of the public: A. Control and collection of stormwater runoff through positive drainage and curbing directing it towards the drainage inlets; B. Heavy-duty stormwater drain manhole covers and catch basin grates have been designed to withstand H20 loading; C. Reduction of peak discharge rates from the site in the post-development condition as compared to the pre-developed conditions; D. Development and implementation of an Operations & Maintenance Plan to ensure the stormwater management system continues to function as designed. Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 5 6. Estimated Cost of Maintenance The following budget was prepared as an estimate of inspection and maintenance costs for the stormwater management system. The budget is an estimate only as the costs may vary depending on the level of sediment accumulation and frequency of maintenance tasks required. BMP Inspections Number of Occurrences Maintenance Cost Number of Structures Sum Bio-Retention Areas 12/year $50 1 $600 Barracuda Water Quality Unit 2/year $100 1 $200 Total Estimated Annual Cost of Inspections $800 BMP Maintenance Number of Occurrences Maintenance Cost Number of Structures Sum Bio-Retention Areas 2/year $500 1 $1,000 Barracuda Water Quality Unit 2/year $800 1 $800 Total Estimated Annual Cost of Maintenance $1,800 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 1 IG1.08 ©ADS 2020 This installation guide is reference for installing the Barracuda S4, S6, S8 Water Quality Units into a precast concrete structure in the field. The components of the Barracuda Concrete Package are as follows: Please check that all components are on site. Below is a list of tools that may be required for installation. Installation Guide BaySaver Barracuda® S4, S6, S8 Concrete Installation Guide February 2020 (2) A/C Stainless Steel Tooth Set (2) B/D Stainless Steel Tooth Set (1) Barracuda Plastic Funnel (4) Stainless Steel Funnel Mounting Flanges (1) Roll of Conseal (14) Concrete Anchor ¼ x 2¼” S4 (4) Stainless Steel Funnel Mounting Flanges (3) Roll of Conseal (14) Concrete Anchor ¼ x 2¼” S6 (8) Stainless Steel Funnel Mounting Flanges (4) Roll of Conseal (18) Concrete Anchor ¼ x 2¼” S8 □ 1/4” Diameter Carbide Tipped Concrete Bit □ Standard Electrical or Battery Operated Drill □ Adjustable Wrench □ Marker for writing on the concrete wall □ Hammer Drill for Concrete (Fits the 1/4” Diameter Concrete Drill Bit) □ 7/16” Driver or deep socket for installation of provided ¼” Concrete Wedge Anchors. □ Hammer □ Level □ Ladder that will extend to bottom of the structure □ Safety Glasses □ Hard Hat □ Protective Gloves □ Site Drawings □ ADS Design Layout 2 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com IG1.08 ©ADS 2020 Installation Instructions (These directions assume the manhole base and riser have been assembled, but that the top slab has not been set). *Do not insert the inlet or outlet pipes until after the Barracuda internals have been installed. If pipes must be inserted in advance, the pipes should not protrude into the structure as they will interfere with installation of the bowl. 1. Mount the four sets of teeth vertically inside the manhole sump. Using the engineer’s plans or the ADS layout, determine the correct orientation for the plastic funnel outlet hole in relation to the outlet pipe (Figures 1 and 4). The first set of teeth will be mounted under the center of the outlet hole. Mark that location with a plumb vertical line, this will serve as the “12 o’ clock” landmark in the manhole. Repeat this process to mark lines at the 3, 6, and 9 o’ clock positions for a total of four. 2. Each kit includes four sets of teeth. Two of these sets are stamped with the letters A and C. The other two sets are stamped B and D. The ADS layout w ill label each tooth set location with the letter A, B, C, or D (Figure 4). You will install each set of teeth in the correct location, with the indicated letter facing up (figure 3). See Table 1 for the correct elevation for the top anchor location of each tooth set, measured from the sump floor. For example, for an S4 Barracuda the top anchor of an A or D indicated set of teeth will be 50” off the sump floor. Mark the top anchor elevations on each of your four vertical lines (figure 2), noting that A or D sets of teeth will be at a different height that B or C sets. 3. To fasten the sets of the teeth to the manhole, use the ¼” concrete drill bit and drill holes approximately 1.25” deep at your marked top anchor locations. Using a hammer, lightly tap the concrete anchors into the drilled holes (figure 3). Hang the tooth set on the top anchor with the correct letter facing up and use a locking nut to loosely secure the tooth set to the wall (do not fully tighten the locking nut at this point). With the set of teeth hanging from the top anchor, line up and mark the bottom anchor location and drill the the hole. Then hammer the bottom anchor in place and secure the teeth with a lock nut. Use an adjustable or socket wrench to tighten the top and bottom locking nuts so that the teeth are firmly secured to the wall (figure 5). Use the same process for all four sets of teeth. Figure 1 Outlet Figure 4 Figure 2 Figure 3 Figure 5 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 3 IG1.08 ©ADS 2020 4. Next, you’ll install mounting flanges for the Barracuda plastic funnel. These flanges need to be installed at the same height, as indicated by model in Table 1. For example, the anchor holes for S4 flanges should be drilled 80” from the sump floor. S4 and S6 models have four flanges and the need to be evenly spaced at 12, 3, 6, and 9 o’clock positions. S8 funnels require eight flanges that als o need to be evenly spaced around the inside of the manhole. Use the same anchor procedure as before, using the ¼” concrete drill bit to drill 1.25” deep holes. Hammer the anchors in place and use locking nuts to firmly secure the flanges (figure 6). 5. Lower the plastic funnel into the structure (figure 7), orienting the weir and outlet hole as depicted in the ADS layout (as identified in step 1). S6 and S8 units have eyebolts on the top of the funnel to assist in lifting. If the eyebolts are misplaced, S6 units have 3/8”-16 threads and S8 units utilize ½”-13 threads. 6. Next, you’ll use Conseal to fill any gaps around the funnel. S6 and S8 units are provided with a metal funnel plug. This plug is placed in the funnel opening for worker safety and must be utilized ANYTIME SOMEONE ENTERS THE STRUCTURE. Unroll the Conseal and wedge it between the funnel and manhole to create a seal (figure 8). Conseal should also be used to seal between the vertical edges of the weir wall and the manhole. The plastic funnel can expand with high temperature. Installing the funnel during cooler parts of the day, or keeping the funnel shaded until installation can mitigate fitment issues. Once the Conseal is installed, the internal component installation is complete. The funnel plug may be discarded (if applicable), and the top slab can be set. If the application calls for a grated inlet, orient the slab so the grate is above the inlet (large bowl) side of the plastic funnel. For maintenance details, please refer to the Barracuda Maintenance Manual. If the application requires a trash rack or oil boom, reference the appropriate supplementary installation instructions. Table 1 S4 S6 S8 Top Anchor Elevation from Sump Floor (A or D tooth indication) 50” (1270 mm) 58” (1475 mm) 74” (1880 mm) Top Anchor Elevation from Sump Floor (B or C tooth indication) 60” (1525 mm) 68” (1725 mm) 90” (2285 mm) Funnel Flange Anchor Elevation from Sump Floor 80” (2030 mm) 80” (2030 mm) 130” (3300 mm) Note: distances can be +/- 1-2inches (25-50mm) from these locations for the A, D, B, and C teeth, but flange elevations should be adhered to as much as possible and can only be lowered a maximum of 1inch (25mm) from these values listed above. This guide is intended for field installations of Barracuda S4, S6, and S8 water quality units into precast manholes. For pre - casters installing internal components prior to jobsite delivery, contact ADS for possible modifications to component elevati ons. Figure 8 Figure 6 Figure 7 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com 1 MG1.01 ©ADS 2017 One of the advantages of the BaySaver Barracuda is the ease of maintenance. Like any system that collects pollutants, the BaySaver Barracuda must be maintained for continued effectiveness. Maintenance is a simple procedure performed using a vacuum truck or similar equipment. The systems were designed to minimize the volume of water removed during routine maintenance, reducing disposal costs. Contractors can access the pollutants stored in the manhole through the manhole cover. This allows them to gain vacuum hose access to the bottom of the manhole to remove sediment and trash. There is no confined space entry necessary for inspection or maintenance. The entire maintenance procedure typically takes from 2 to 4 hours, depending on the size of the system, the captured material, and the capacity of the vacuum truck. Local regulations may apply to the maintenance procedure. Safe an d legal disposal of pollutants is the responsibility of the maintenance contractor. Maintenance should be performed only by a qualified contractor. Inspection and Cleaning Cycle Periodic inspection is needed to determine the need for and frequency of maint enance. You should begin inspecting as soon as construction is complete and thereafter on an annual basis. Typically, the system needs to be cleaned every 1-3 years. Excessive oils, fuels or sediments may reduce the maintenance cycle. Periodic inspection is important. Determining When to Clean To determine the sediment depth, the maintenance contractor should lower a stadia rod into the manhole until it contacts the top of the captured sediment and mark that spot on the rod. Then push the probe through to the bottom of the sump and mark that spot to determine sediment depth. Maintenance should occur when the sediment has reached the levels indicated in the Storage Capacity Chart. BaySaver Barracuda Storage Capacities Model Manhole Diameter Treatment Chamber Capacity Standard Sediment Capacity (20” depth) NJDEP Sediment Capacity (50% of standard depth) S3 36” 212 gallons 0.44 cubic yards 0.22 cubic yards S4 48” 564 gallons 0.78 cubic yards 0.39 cubic yards S5 60” 881 gallons 1.21 cubic yards 0.61 cubic yards S6 72” 1269 gallons 1.75 cubic yards 0.88 cubic yards S8 96” 3835 gallons 3.10 cubic yards 1.55 cubic yards S10 120” 7496 gallons 4.85 cubic yards 2.43 cubic yards Maintenance Instructions 1. Remove the manhole cover to provide access to the pollutant storage. Pollutants are stored in the sump, below the bowl assembly visible from the surface. You’ll access this area through the 10” diameter access cylinder. Maintenance Guide BaySaver BarracudaTM July 2017 2 4640 TRUEMAN BLVD. HILLIARD, OH 43026 (800) 821-6710 www.ads-pipe.com MG1.01 ©ADS 2017 2. Use a vacuum truck or other similar equipment to remove all water, debris, oils and sediment. See figure 1. 3. Use a high pressure hose to clean the manhole of all the remaining sediment and debris. Then, use the vacuum truck to remove the water. 4. Fill the cleaned manhole with water until the level reaches the invert of the outlet pipe. 5. Replace the manhole cover. 6. Dispose of the polluted water, oils, sediment and trash at an approved facility. • Local regulations prohibit the discharge of solid material into the sanitary system. Check with the local sewer authority for authority to discharge the liquid. • Some localities treat the pollutants as leachate. Check with local regulators about disposal requirements. • Additional local regulations may apply to the maintenance procedure. Figure 1 Project: Responsible Party: Address: Date: BPM Name:Page: 1 of 2 Operation & Maintenance Inspection Checklist BMP Element:Potential Problem:Pass Fail Recommended Remediation Bituminous Concrete Roadway Build-up of sediment over the winter months and collection of leaves during the fall months. Sediment has accumulated over mulched surface. Erosion has occurred at inlets. Areas are devoid of mulch. Litter and/or debris has accumulated in bio-retention area. Vegetation has died or is distressed. Stormwater Piping Blockage of inlet/outlet pipes due to debris or sediment accumulation. Inspector's Signature Date Bio-Retention Areas Remove sediment and mulch mixture and replace mulch. Repair any eroded areas and replace with appropriate materials. Replace mulch as necessary. Remove litter and/or debris. Replace vegetation as necessary. Resolution: Sweep roadway using a high-efficiency street sweeper. Remove any debris and sediment via proper means. Dispose of debris/sediment in accordance with local & state regulations Downspout connections have been damaged or disconnected. Roof leaders are surcharging at the downspout connections Barracuda Water Quality Unit Sediment has accumulated to a depth greater that the original design depth for sediment storage. Roof Leaders Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 1 Introduction Per the Massachusetts Stormwater Handbook, project proponents must consider environmentally sensitive site design and low impact development techniques to effectively manage stormwater. As a part of the proposed project, the proponent has considered a number of environmentally sensitive, low impact development techniques to prevent the generation of stormwater and non- point source pollution. The following is a detailed description of the considerations for each low impact development measure. For ease of review, RLA has provided the consideration of each measure as detailed in the Massachusetts Stormwater Report Checklist. Low Impact Development (LID) Measures 1. Environmentally Sensitive Project Approach The property where the project is proposed has been previously developed as a multi-use building. The project proposes to demolish the existing buildings and construct 3 new residential buildings. Two significant beech trees are existing on the site. Pro posed work has been designed to retain these trees. Tree protection in compliance with city standards will be used during construction. No vegetation clearing is proposed as part of the project. Additionally, no stormwater management system exists on the site. Under current conditions, untreated stormwater flows directly into city stormwater infrastructure. Under proposed conditions a new stormwater management system will be installed in conformance with municipal regulations. This stormwater management system has been designed to incorporate various environmentally sensitive site design techniques including bio-retention areas and pervious paver parking areas. There are no wetland resource areas located on or adjacent to the property. 2. No disturbance to any Wetland Resource Areas There are no wetland resource areas or buffer zone located on the property. No disturbance to any wetland areas, or their associated buffer zones, is proposed as part of this project. 3. Site Design Practices (e.g. clustered development, reduced frontage setbacks) No alteration are proposed to the parcel boundaries as part of this project therefore no opportunities are available for clustered development or frontage reduction. 4. Reduced Impervious Area (Redevelopment Only) The project has been designed to limit new impervious areas to functional minimums. Unfortunately the project could not be designed to reduce on-site impervious areas. 5. Minimizing disturbance to existing trees and shrubs The existing parcel has been historically developed with the various existing buildings, associated driveway/parking paved areas, and landscaped areas. All existing vegetation, including two specimen beech trees will be retained. Additionally, the project proposes a Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 2 bioretention area planted with native plants with high wildlife characteristics. This area will provide habitat not currently available on site. 6. LID Site Design Credit Requested No LID Site Design Credit is requested for the proposed project. 7. Use of “country drainage” versus curb and gutter conveyance and pipe Roadside swales are best management practices that require a greater footprint of development to facilitate the grading of the conveyance channel. Due to the urban nature or this project, gutter conveyance methods may pose a hazard to drivers and pedestrians. In order to provide a stormwater management system in conformance with the city and state regulations water quality regulations, and reduce the overall development footprint, underground conveyance piping is being utilized to convey stormwater. 8. Bioretention Cells (includes Rain Gardens) The proposed stormwater management system has incorporated a bio-retention area on-site. The bio-retention area has been designed with an overflow inlet and an underdrain system to promote infiltration. The bioretention area includes native plants with high wildlife characteristics. This area will provide habitat not currently available on site. Additionally, in an effort to minimize any sediment reaching the bioretention area, the treatment train process includes a proprietary sedimentation device. 9. Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Constructed stormwater wetlands require very specific design scenarios such as proximity to existing wetland areas, large tributary areas to support wetland characteristics and high groundwater elevations among others. Local groundwater elevations on site are not favorable and there are no wetland impacts proposed, therefore, a constructed wetland has not been proposed. 10. Treebox Filter Treebox filters were considered for the project during the conceptual design phase, however, the stormwater management system is utilizing other environmentally sensitive site design best management practices such as bio-retention areas and pervious pavers which complement the site design layout in a more efficient manner. Trees have been proposed adjacent to proposed paved areas in order to satisfy the intent of this LID measure. 11. Water Quality Swale Water quality swales require a site design that lends itself to providing hydraulic residence times within the swale to allow for the suspended solids to settle out of the runoff. Due to the layout of the site and the utilization of other environmentally sensitive site design best management practices, a feasible location to convey runoff for treatment within a water quality swale was not readily available. Therefore, a water quality swale has not been included as part of the treatment train process for the stormwater management system. 12. Grass Channel Proposed Residential Development Stormwater Drainage Report 29 Sherman Avenue Northampton, Massachusetts R Levesque Associates, Inc. Page 3 Grassed channels, as well as water quality swales, are best management practices that require a greater footprint of development in order to facilitate the grading of the swale. Projects located in urban environments typically do not have excess area to be utilized for surface conveyance of runoff. Furthermore, grassed channels do not provide any water quality treatment characteristics and are strictly used as a conveyance practice. Due to the layout of the site and the constraints imposed by the urban nature of the property, a feasible location to convey runoff via a grass channel while providing a stormwater management system which meets the requirements of the MassDEP Handbook was not feasible. 13. Green Roof Green roofs are typically associated with flat roofed structures where roof access can be readily incorporated into the architecture. Based on the proposed building layouts, green roofs are not suitable for the buildings associated with the project. 14. Other Please see the Stormwater Report for more information. Northampton DPW Inspection Schedule Sign-Off Sheet Inspection Schedule Description Date of Inspection Inspector Passed Failed Notes Initial Inspection Prior to approval of any plan. After site clearing Rough Grading Final Grading Bury Inspection Prior to backfilling of any underground drainage or stormwater conveyance structures. Final Inspection Conducted when all work, inlcuding construction of stormwater management facilities and landscaping have been completed. Final inspection shall include a full, dated TV inspcetion of all stormwater pipes installed. Erosion and Sediment Control Inspections