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2021-02-18 Stormwater Report - 1087 Westhampton Rd1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 1 Table of Contents I. Introduction 2 II. Existing Conditions 3 III. Proposed Conditions 3 IV. Calculations and Design 4 V. MADEP Stormwater Standards Compliance 6 Figures Figure 1 Existing Conditions and Hydrology Figure 2 Proposed Plan and Hydrology Appendices Appendix A NRCS Soil Report Appendix B Test Pit Report Appendix C Stormwater Hydrology Calculations Appendix D Groundwater Recharge Appendix E Water Quality Calculations Appendix F Stormwater Management System – Operation & Maintenance Plan Appendix G Massachusetts DEP Stormwater Checklist Appendix H Illicit Discharge Statement Referenced Documents Plans: SW-1: Existing Conditions SW-2: Lot 4 Stormwater Permit Plan 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 2 The proposed development is the construction of a single-family home and driveway on a vacant forested lot at 1087 Westhampton Road. Berkshire Design Group has prepared a Stormwater Management plan for the site in compliance with the Massachusetts Stormwater Handbook. This report summarizes the design of the system and documents how the design complies with those standards. I. Introduction The proposed site is a 17.5 acre mostly wooded parcel with some steep grades, wetlands to the south, east and northeast and a new development to the west. The proposed work will include the construction of an 875’ driveway to a single-family home. Stormwater improvements are proposed at the house site and along the driveway. The parcel is located on the north side of Westhampton Road about 900 ft west of Glendale Road. From Westhampton Road the planned driveway follows the eastern property line for approximately 400’ and then slopes up a steep gradient to the house site. Soil Data NRCS Soil Survey The NRCS Soil Survey reports that the on-site soils are variable with Hinckley loamy sand (Hydrologic Soil Group – HSG A) near Westhampton Road and various fine loamy sands (HSG B-D) on the remainder of the parcel. The USGS Surficial Geology survey indicates that the majority of the parcel is part of a drumlin landform making till the soil parent material. The portion of the property near Westhampton Road includes sand and gravel outwash coarse deposits. The NRCS Soil Report for the site is attached in Appendix A. Subsurface Exploration A total of six test pits were completed on January 22, 2021. The soil evaluation report is attached as Appendix B. The test pits indicated that the soils included loamy sand and sandy loam in the upper parts of the lot with varying depths to estimated seasonal high groundwater (ESHGW). At the top of the site relatively shallow ESHGW was found at 30”. Further down along the driveway ESHGW was deeper at about 60”. Just above and below the steeper portion of the site groundwater was just below the surface. Near Westhampton Road soils were sandy, characteristic of outwash, and ESHGW was estimated at 48”. Site Limits Site limits were based both on the parcel lines as well as the contributing drainage area to the west. Based on the site topography, runoff flows in three directions.. Study points were established west of the driveway at the wetland on Westhampton Road (Study Point 1), east of the driveway at the lower bordering vegetated wetland and behind the existing homes (Study Point 2) and on the north property line at the upper bordering vegetated wetland (Study Point 3) to model pre and post peak runoff (see Figures 1 and 2). 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 3 II. Existing Conditions An Existing Conditions and Hydrology Plan is shown on Figure 1. The existing hydrology was analyzed as four major drainage areas, E1 through E4 with 3 study points. Because runoff from the newly developed area to the west is a major contributor to the site runoff, it was included in the overall analysis. Drainage area E1 includes the area tributary to the Westhampton Road wetland. Area E1 is comprised of a portion of Westhampton Road, a portion of a common drive, steeply sloped forested areas as well as meadow within the wetland. The wetland includes two City of Northampton catch basins, one on the east side adjacent to the proposed driveway and a bigger structure to the west, designated as Study Point 1. Drainage area E2 includes two of the lots off the common drive as well as a portion of the common driveway, an area which is tributary to a detention basin located west of the proposed site and draining onto it. Although the detention basin outlet appears to currently drain to Study Point 2, its drainage area historically (prior to the development of the common drive) appears to have drained to the Westhampton Road wetland. As such, the existing modeling directs this flow to Study Point 1. Drainage area E3 includes the portion of the parcel which drains to Study Point 2, a bordering vegetated wetland located behind four homes on Westhampton Road. Drainage area E4 includes the northern part of the project site, an area which drains to Study Point 3, a bordering vegetated wetland which drains north and then (off the property) west. III. Proposed Conditions The proposed conditions plan is provided on Figure 2 along with the proposed hydrology. The proposed work maintains existing stormwater flow patterns and includes a rain garden, wet swale and three small infiltration basins to treat and infiltrate runoff from the driveway and portions of the proposed dwelling roof. The proposed site is modeled with four drainage areas matching the patterns found in existing conditions. Areas P1A and P1B replace area E1. Area P1A is the undisturbed area which includes part of the common drive and wetlands. Area P1B includes approximately 540’ of the new driveway and the stormwater improvements. Area P2 is equivalent to area E2, encompassing the drainage area to the existing common drive detention basin. As in the existing model this drainage area is routed to Study Point 1. Areas P3 (A-D) are tributary to Study Point 2. P3A is an undeveloped sloped area west of the driveway conveyed east through a culvert. P3D is the undeveloped area east of the driveway which sheet flows to the bordering vegetated wetland and Study Point 2. P3B and P3C include portions of the driveway draining to infiltration pools which treat, infiltrate. In large storm events, the pools will overflow and sheet flow to the Study Point. Drainage area P4A and P4B drain to Study Point 3. P4A includes the front of the house roof, the top of the driveway and apron. This area is directed to a filtering rain garden for treatment. The rain garden underdrain is directed to Study Point 3, as is the overflow weir. Area P4B is the remaining area which includes a portion of the house roof. This large area drains north to Study Point 3. 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 4 Detailed analysis of lower driveway In addition to the overall drainage area analysis presented above, a detailed analysis of the lower driveway area (540 linear feet) draining to Westhampton Road was completed to show that existing flows are not exceeded at this location. The study point for this analysis is an existing catch basin just east of the proposed driveway. The existing area draining to this location is shown on Figure 1 and the proposed area is shown on Figure 2. The area is bounded by the property line to the east and the top of the wet swale to the west. Results of the analysis are presented below. Water Quality Proposed development includes total impervious areas of 15,720 sf, of which 4,220 sf is the building roof. The proposed design provides treatment with sheet flow off of the driveway to a gravel diaphragm, followed by overland flow to several different BMPs including a filtering rain garden, infiltration areas, and a wet swale followed by infiltration. IV. Calculations and Design Water Quantity Drainage calculations were performed on HydroCAD Stormwater Modeling System version 10.0 using Soil Conservation Service (SCS) TR-20 methodology. The SCS method is based on rainfall observations, which were used to develop the Intensity-Duration-Frequency relationship, or IDF curve. The mass curve is a dimensionless distribution of rainfall over time, which indicates the fraction of the rainfall event that occurs at a given time within a 24-hour precipitation event. This synthetic distribution develops peak rates for storms of varying duration and intensities. The SCS distribution provides a cumulative rainfall at any point in time and allows volume-dependent routing runoff calculations to occur. These calculations are included in Appendix C. Rainfall values are taken from the latest NRCS-rain tables and are listed in Table 1. The watershed boundaries for calculation purposes are divided according to the proposed site grading and the parcel boundary. The curve numbers (CNs) for the existing and proposed sub- catchment area are based on the soil type and the existing and proposed cover conditions at the site. The time of concentration (Tc) for large sub-areas with extensive pervious areas is calculated using sheet flow, followed by shallow concentrated flow and channel flow if warranted. Small sub- area TCs are set at a minimum of 6 minutes. Reach routes are added for culvert discharges which occur at significant distances above study points. Conservatively the Storage-Indication method is used for reach routing. Calculations were performed for the 2-, 10-, and 100-year frequency storms under existing and proposed conditions. The results of the calculations are presented in Table 1 below. Appendix C presents the HydroCAD output reports. 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 5 Table 1. Runoff and Volume Summary Tables Point of Analysis 2-Year Storm 3.07” 10-Year Storm 4.47” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing – Study Pt 1 3.66 9.19 26.68 Proposed – Study Pt 1 3.63 8.83 27.09 Existing – Study Pt 2 1.17 3.50 10.45 Proposed – Study Pt 2 1.06 3.11 9.16 Existing – Study Pt 3 0.50 2.02 7.18 Proposed – Study Pt 3 0.43 1.78 6.84 Point of Analysis 2-Year Storm 3.07” 10-Year Storm 4.47” 100-Year Storm 7.68” Volume Volume Volume Existing – Study Pt 1 0.668 1.386 3.326 Proposed – Study Pt 1 0.657 1.336 3.264 Existing – Study Pt 2 0.183 0.446 1.236 Proposed – Study Pt 2 0.177 0.423 1.160 Existing – Study Pt 3 0.144 0.403 1.242 Proposed – Study Pt 3 0.145 0.383 1.149 The analysis shows that peak flow rates for the site are maintained below existing conditions with the exception of a slight increase for the 100-year storm at Study Point 1. All volumes are decreased in the post development condition due to the proposed stormwater infiltration practices 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 6 Detailed Driveway Analysis – Sta 0+00 to 5+90 The analysis of the lower portion of the driveway and its effect on flow into the existing city catch basin also shows a decrease in post development conditions. Table 2 provides the results of the peak runoff analysis. Volumes are decrease in a similar fashion to the peak flows since the 2 and 10-year storm runoff infiltrates in the proposed basin. (see model in Appendix C). Table 2. Driveway peak runoff results Point of Analysis 2-Year Storm 3.07” 10-Year Storm 4.47” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing CB on Westhampton Road 0.05 0.23 0.92 Proposed – Existing CB 0 0 0.73 Water Quality Water quality at the proposed site is addressed with a filtering rain garden, a wet swale and three separate infiltration areas. Roof area (approximately 1,975 sf) which is not conveyed to water quality practice, is conveyed to the wooded area around the building site via disconnected downspouts. The Total Suspended Solids removal for the site provided by the practices is calculated at an average of 91%. Water quality volume is provided by storage below the weirs within the rain garden and infiltration areas . Calculations supporting these conclusions are included in Appendix E. Erosion & Sedimentation Control The project plan set includes provisions for erosion control during construction. A stone tracking pad is proposed at the entrance of the driveway along with silt fence along both sides of the driveway at the limit of disturbance. V. MADEP Stormwater Standards Compliance The following section details how the project will meet the DEP Stormwater Management Policy’s ten stormwater management standards. LID By locating the driveway along the eastern property line, the project avoids disturbance of the wetland fronting the parcel. Disturbance to existing vegetation will be limited to the driveway corridor and house site area. Sheet flow and drainage swales are proposed to convey runoff. Several 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 7 small treatment and infiltration practices are provided below the house and along the driveway including a rain garden, wet swale, and three infiltration areas. Providing water quality treatment and infiltration at multiple locations provides for treatment and recharge throughout the site rather than at one central location. Standard 1 - Untreated Stormwater Discharge Through multiple treatment practices located along the proposed driveway, the proposed project provides treatment of runoff from new impervious surfaces. Proposed culvert and swale outlets have been designed to prevent scour and erosion. Standard 2 - Post-Development Peak Discharge Rates The proposed design and infiltration facilities provide attenuation of discharge rates such that 2 and 10-year post development discharge rates are less than pre-development peak discharge rates leaving the site. Post development 100-year peak flow rates are less than pre-development peak discharge rates for study points 2 and 3. For study point 1, the post 100-year peak flow rate exceeds the pre-development rate by 0.4 cfs (1.5%); the volume produced by the 100-year storm event is reduced by 2% in the post development condition. The analysis of the driveway construction shows that driveway runoff to study point 1 is below existing conditions runoff in all storm events. Based on this analysis, it is our opinion that the minimal increase in peak flow rates during the 100- year storm will not result in an increase in off-site flooding, and that the proposed design meets Standard 2. These results are discussed in detail under “Peak Runoff Rate” in Section IV, above. Standard 3 - Recharge to Groundwater The site is comprised of HSG soil group types A through D. Recharge of the increased impervious area is provided within the proposed infiltration areas. Although infiltration is limited to those site areas with HSG A and B, sufficient infiltration is provided to meet the requirements for the overall site. Calculations of recharge are included within Appendix D. Standard 4 – Water Quality Runoff from the driveway is treated with several practices including a gravel filter strip, rain garden, wet swale and infiltration areas providing an overall TSS removal of 91%. The water quality volume is calculated based on 0.5”. For the proposed impervious area, the required water quality volume is 655 cu. ft. At a total of 4,485 cu. ft. the proposed facilities provide more than 6 times the required volume. Further discussion of this standard is included under “Water Quality” in Section III and in Appendix E. Standard 5 - Higher Potential Pollutant Loads This is not applicable to this project. 1087 Westhampton Road, February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 8 Standard 6 - Protection of Critical Areas This is not applicable to this project. Standard 7 - Redevelopment Projects This is not applicable to this project. Standard 8 - Erosion/Sediment Control Proposed erosion and sediment controls are shown on the drainage plan for the site. Standard 9 - Operation/Maintenance Plan An Operation and Maintenance Plan for the proposed project is included in Appendix F. It includes general controls for construction and long term maintenance of the gravel filter strip, rain garden, wet swale and infiltration areas. Standard 10 – Prohibition of Illicit Discharges An Illicit Discharge Statement is attached in Appendix H. 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group FIGURES Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The Berkshire Design Group, Inc. c 1087 WESTHAMPTON ROAD NORTHAMPTON, MA Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Land Surveying FIG 1 FEBRUARY 18, 2021 1" = 150' LMC EXISTING CONDITIONS AND HYDROLOGY 0 30015075 450 IMPERVIOUS AREA PARCEL BOUNDARY DRAINAGE AREA BOUNDARY SOILS BOUNDARY 50'/100' WETLAND BUFFER TIME OF CONCENTRATION OR REACH GIS CONTOUR CMC PROPOSED INFILTRATION BASINOUTLET = EX CB GR ELEV = 309.21PR WET SWALE12' DRIVEWAY WITHGRAVEL FILTER STRIPPR INFILTRATION BASINSOVERFLOW WEIRPR FILTERING RAIN GARDEN12" HDPE CULVERT12"RCP CULVERT12" HDPE CULVERTChecked By:Drawn By:RevisionsScale:Date:Sheet NumberThis drawing is not intended nor shall it be used forconstruction purposes unless the signed professional seal of aregistered landscape architect, civil engineer or land surveyoremployed by The Berkshire Design Group, Inc. is affixed above.Do not scale drawing for quantity take-offs or construction. Usewritten dimensions only. If dimensions are incomplete, contactThe Berkshire Design Group Inc. for clarification.Copyright The Berkshire Design Group, Inc.This drawing and all of its contents are the express property ofThe Berkshire Design Group, Inc., and shall not be copied orused in any way without the written consent of The BerkshireDesign Group, Inc.cWeb: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignLand SurveyingFIG2February 18, 20211" = 150'LMCPROPOSED CONDITIONSAND HYDROLOGY030015075450CMC IMPERVIOUS AREAPARCEL BOUNDARYDRAINAGE AREA BOUNDARYSOILS BOUNDARY50'/100' WETLAND BUFFERTIME OF CONCENTRATIONOR REACHGIS CONTOUR 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix A– NRCS Soils Report 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 1087 Westhampton Road, Northampton, MA Natural Resources Conservation Service January 8, 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 Soil Map..................................................................................................................5 Soil Map................................................................................................................6 Legend..................................................................................................................7 Map Unit Legend..................................................................................................9 Map Unit Descriptions..........................................................................................9 Hampshire County, Massachusetts, Central Part............................................11 31A—Walpole sandy loam, 0 to 3 percent slopes.......................................11 51A—Swansea muck, 0 to 1 percent slopes...............................................12 253A—Hinckley loamy sand, 0 to 3 percent slopes....................................14 260A—Sudbury fine sandy loam, 0 to 3 percent slopes.............................15 306C—Paxton fine sandy loam, 8 to 15 percent slopes, very stony...........16 311B—Woodbridge fine sandy loam, 0 to 8 percent slopes, very stony.....18 406B—Charlton fine sandy loam, 3 to 8 percent slopes, very stony...........19 711E—Charlton-Rock outcrop-Hollis complex, steep.................................21 4 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. 5 6 Custom Soil Resource Report Soil Map 46851404685210468528046853504685420468549046855604685140468521046852804685350468542046854904685560687580 687650 687720 687790 687860 687930 688000 688070 688140 688210 687580 687650 687720 687790 687860 687930 688000 688070 688140 688210 42° 17' 59'' N 72° 43' 29'' W42° 17' 59'' N72° 42' 58'' W42° 17' 44'' N 72° 43' 29'' W42° 17' 44'' N 72° 42' 58'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 150 300 600 900 Feet 0 45 90 180 270 Meters Map Scale: 1:3,210 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: Mar 15, 2016—Oct 30, 2017 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Custom Soil Resource Report 7 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 8 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 31A Walpole sandy loam, 0 to 3 percent slopes 8.8 23.3% 51A Swansea muck, 0 to 1 percent slopes 0.9 2.3% 253A Hinckley loamy sand, 0 to 3 percent slopes 5.9 15.6% 260A Sudbury fine sandy loam, 0 to 3 percent slopes 2.4 6.2% 306C Paxton fine sandy loam, 8 to 15 percent slopes, very stony 14.3 37.8% 311B Woodbridge fine sandy loam, 0 to 8 percent slopes, very stony 0.0 0.1% 406B Charlton fine sandy loam, 3 to 8 percent slopes, very stony 5.4 14.3% 711E Charlton-Rock outcrop-Hollis complex, steep 0.1 0.3% Totals for Area of Interest 37.8 100.0% 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 Custom Soil Resource Report 9 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, 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 10 Hampshire County, Massachusetts, Central Part 31A—Walpole sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2svkl Elevation: 0 to 1,020 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 250 days Farmland classification: Not prime farmland Map Unit Composition Walpole and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Walpole Setting Landform:Deltas, depressions, outwash terraces, outwash plains, depressions Landform position (two-dimensional):Toeslope Landform position (three-dimensional):Tread, talf, dip Down-slope shape:Concave Across-slope shape:Concave Parent material:Sandy glaciofluvial deposits derived from igneous, metamorphic and sedimentary rock Typical profile Oe - 0 to 1 inches: mucky peat A - 1 to 7 inches: sandy loam Bg - 7 to 21 inches: sandy loam BC - 21 to 25 inches: gravelly sandy loam C - 25 to 65 inches: very gravelly sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Poorly drained Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.14 to 14.17 in/hr) Depth to water table:About 0 to 4 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water capacity:Moderate (about 6.4 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4w Hydrologic Soil Group: B/D Ecological site: F144AY028MA - Wet Outwash Hydric soil rating: Yes Custom Soil Resource Report 11 Minor Components Sudbury Percent of map unit:10 percent Landform:Deltas, outwash plains, terraces Landform position (two-dimensional):Footslope Landform position (three-dimensional):Tread, dip Down-slope shape:Concave Across-slope shape:Linear Hydric soil rating: No Scarboro Percent of map unit:10 percent Landform:Outwash terraces, deltas, outwash plains Landform position (two-dimensional):Toeslope Landform position (three-dimensional):Tread, dip Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes 51A—Swansea muck, 0 to 1 percent slopes Map Unit Setting National map unit symbol: 2trl2 Elevation: 0 to 1,140 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Not prime farmland Map Unit Composition Swansea and similar soils:80 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Swansea Setting Landform:Swamps, bogs Landform position (three-dimensional):Dip Down-slope shape:Concave Across-slope shape:Concave Parent material:Highly decomposed organic material over loose sandy and gravelly glaciofluvial deposits Typical profile Oa1 - 0 to 24 inches: muck Oa2 - 24 to 34 inches: muck Cg - 34 to 79 inches: coarse sand Custom Soil Resource Report 12 Properties and qualities Slope:0 to 1 percent Depth to restrictive feature:More than 80 inches Drainage class:Very poorly drained Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.14 to 14.17 in/hr) Depth to water table:About 0 to 6 inches Frequency of flooding:Rare Frequency of ponding:Frequent Available water capacity:Very high (about 16.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8w Hydrologic Soil Group: B/D Ecological site: F144AY043MA - Acidic Organic Wetlands Hydric soil rating: Yes Minor Components Freetown Percent of map unit:10 percent Landform:Bogs, swamps Landform position (three-dimensional):Dip Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes Whitman Percent of map unit:5 percent Landform:Depressions, drainageways Landform position (two-dimensional):Toeslope Landform position (three-dimensional):Base slope Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes Scarboro Percent of map unit:5 percent Landform:Drainageways, depressions Landform position (two-dimensional):Toeslope Landform position (three-dimensional):Base slope, tread, dip Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes Custom Soil Resource Report 13 253A—Hinckley loamy sand, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 2svm7 Elevation: 0 to 1,420 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Farmland of statewide importance Map Unit Composition Hinckley and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hinckley Setting Landform:Outwash plains, outwash terraces, outwash deltas, kame terraces Landform position (three-dimensional):Tread Down-slope shape:Linear, concave, convex Across-slope shape:Linear, convex, concave Parent material:Sandy and gravelly glaciofluvial deposits derived from gneiss and/or granite and/or schist Typical profile Oe - 0 to 1 inches: moderately decomposed plant material A - 1 to 8 inches: loamy sand Bw1 - 8 to 11 inches: gravelly loamy sand Bw2 - 11 to 16 inches: gravelly loamy sand BC - 16 to 19 inches: very gravelly loamy sand C - 19 to 65 inches: very gravelly sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Excessively drained Runoff class: Negligible Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very high (1.42 to 99.90 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water capacity:Low (about 3.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Custom Soil Resource Report 14 Ecological site: F144AY022MA - Dry Outwash Hydric soil rating: No Minor Components Merrimac Percent of map unit:5 percent Landform:Kame terraces, outwash terraces, outwash deltas Landform position (three-dimensional):Tread Down-slope shape:Convex, concave, linear Across-slope shape:Linear, convex, concave Hydric soil rating: No Windsor Percent of map unit:5 percent Landform:Outwash deltas, outwash terraces, kame terraces Landform position (three-dimensional):Tread Down-slope shape:Convex, linear, concave Across-slope shape:Convex, linear, concave Hydric soil rating: No Sudbury Percent of map unit:5 percent Landform:Kame terraces, outwash terraces, outwash deltas Landform position (three-dimensional):Tread Down-slope shape:Convex, concave, linear Across-slope shape:Linear, convex, concave Hydric soil rating: No 260A—Sudbury fine sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 9b1z Elevation: 0 to 2,100 feet Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 140 to 240 days Farmland classification: All areas are prime farmland Map Unit Composition Sudbury and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Sudbury Setting Landform:Outwash plains Landform position (two-dimensional):Footslope Landform position (three-dimensional):Tread Down-slope shape:Linear Custom Soil Resource Report 15 Across-slope shape:Concave Parent material:Friable loamy eolian deposits over loose sandy glaciofluvial deposits Typical profile H1 - 0 to 10 inches: fine sandy loam H2 - 10 to 16 inches: fine sandy loam H3 - 16 to 28 inches: gravelly loamy sand H4 - 28 to 60 inches: stratified gravelly sand to very gravelly loamy sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):High (2.00 to 6.00 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Low (about 4.8 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Ecological site: F144AY027MA - Moist Sandy Outwash Hydric soil rating: No Minor Components Hinckley Percent of map unit:5 percent Hydric soil rating: No Merrimac Percent of map unit:5 percent Hydric soil rating: No Walpole Percent of map unit:5 percent Landform:Terraces Hydric soil rating: Yes 306C—Paxton fine sandy loam, 8 to 15 percent slopes, very stony Map Unit Setting National map unit symbol: 2w677 Elevation: 0 to 1,330 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Custom Soil Resource Report 16 Farmland classification: Farmland of statewide importance Map Unit Composition Paxton, very stony, and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Paxton, Very Stony Setting Landform:Drumlins, hills, ground moraines Landform position (two-dimensional):Backslope Landform position (three-dimensional):Side slope Down-slope shape:Linear, convex Across-slope shape:Convex, linear Parent material:Coarse-loamy lodgment till derived from gneiss, granite, and/or schist Typical profile Oe - 0 to 2 inches: moderately decomposed plant material A - 2 to 10 inches: fine sandy loam Bw1 - 10 to 17 inches: fine sandy loam Bw2 - 17 to 28 inches: fine sandy loam Cd - 28 to 67 inches: gravelly fine sandy loam Properties and qualities Slope:8 to 15 percent Surface area covered with cobbles, stones or boulders:1.6 percent Depth to restrictive feature:20 to 43 inches to densic material Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately low (0.00 to 0.14 in/hr) Depth to water table:About 18 to 37 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water capacity:Low (about 4.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: C Ecological site: F144AY007CT - Well Drained Dense Till Uplands Hydric soil rating: No Minor Components Woodbridge, very stony Percent of map unit:8 percent Landform:Ground moraines, drumlins, hills Landform position (two-dimensional):Backslope, footslope Landform position (three-dimensional):Side slope Down-slope shape:Concave Across-slope shape:Linear Hydric soil rating: No Custom Soil Resource Report 17 Charlton, very stony Percent of map unit:5 percent Landform:Hills Landform position (two-dimensional):Backslope Landform position (three-dimensional):Side slope Down-slope shape:Convex Across-slope shape:Convex Hydric soil rating: No Ridgebury, very stony Percent of map unit:2 percent Landform:Drainageways, hills, ground moraines, depressions, drumlins Landform position (two-dimensional):Toeslope, footslope Landform position (three-dimensional):Base slope, head slope Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes 311B—Woodbridge fine sandy loam, 0 to 8 percent slopes, very stony Map Unit Setting National map unit symbol: 2t2qr Elevation: 0 to 1,440 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Farmland of statewide importance Map Unit Composition Woodbridge, very stony, and similar soils:82 percent Minor components:18 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Woodbridge, Very Stony Setting Landform:Drumlins, hills, ground moraines Landform position (two-dimensional):Backslope, footslope, summit Landform position (three-dimensional):Side slope Down-slope shape:Concave Across-slope shape:Linear Parent material:Coarse-loamy lodgment till derived from gneiss, granite, and/or schist Typical profile Oe - 0 to 2 inches: moderately decomposed plant material A - 2 to 9 inches: fine sandy loam Bw1 - 9 to 20 inches: fine sandy loam Bw2 - 20 to 32 inches: fine sandy loam Cd - 32 to 67 inches: gravelly fine sandy loam Custom Soil Resource Report 18 Properties and qualities Slope:0 to 8 percent Surface area covered with cobbles, stones or boulders:1.6 percent Depth to restrictive feature:20 to 43 inches to densic material Drainage class:Moderately well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately low (0.00 to 0.14 in/hr) Depth to water table:About 19 to 27 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water capacity:Low (about 4.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: C/D Ecological site: F144AY037MA - Moist Dense Till Uplands Hydric soil rating: No Minor Components Paxton, very stony Percent of map unit:10 percent Landform:Ground moraines, drumlins, hills Landform position (two-dimensional):Shoulder, backslope, summit Landform position (three-dimensional):Crest, side slope Down-slope shape:Convex, linear Across-slope shape:Convex, linear Hydric soil rating: No Ridgebury, very stony Percent of map unit:8 percent Landform:Ground moraines, depressions, drumlins, drainageways, hills Landform position (two-dimensional):Toeslope Landform position (three-dimensional):Head slope, base slope Down-slope shape:Concave Across-slope shape:Concave Hydric soil rating: Yes 406B—Charlton fine sandy loam, 3 to 8 percent slopes, very stony Map Unit Setting National map unit symbol: 2wh0r Elevation: 0 to 1,570 feet Mean annual precipitation: 36 to 71 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 240 days Farmland classification: Farmland of statewide importance Custom Soil Resource Report 19 Map Unit Composition Charlton, very stony, and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Charlton, Very Stony Setting Landform:Hills, ground moraines, ridges Landform position (two-dimensional):Backslope, shoulder, summit Landform position (three-dimensional):Crest, side slope, nose slope Down-slope shape:Linear, convex Across-slope shape:Convex Parent material:Coarse-loamy melt-out till derived from granite, gneiss, and/or schist Typical profile Oe - 0 to 2 inches: moderately decomposed plant material A - 2 to 4 inches: fine sandy loam Bw - 4 to 27 inches: gravelly fine sandy loam C - 27 to 65 inches: gravelly fine sandy loam Properties and qualities Slope:3 to 8 percent Surface area covered with cobbles, stones or boulders:1.6 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.14 to 14.17 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water capacity:Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6s Hydrologic Soil Group: B Ecological site: F142XB009VT - Acidic Till Upland Hydric soil rating: No Minor Components Sutton, very stony Percent of map unit:5 percent Landform:Hills, ground moraines Landform position (two-dimensional):Footslope Landform position (three-dimensional):Base slope Down-slope shape:Concave Across-slope shape:Linear Hydric soil rating: No Paxton, very stony Percent of map unit:5 percent Custom Soil Resource Report 20 Landform:Drumlins, hills, ground moraines Landform position (two-dimensional):Backslope, shoulder, summit Landform position (three-dimensional):Side slope, crest Down-slope shape:Linear, convex Across-slope shape:Convex Hydric soil rating: No Chatfield, very stony Percent of map unit:3 percent Landform:Hills, ridges Landform position (two-dimensional):Backslope, shoulder, summit Landform position (three-dimensional):Crest, side slope, nose slope Down-slope shape:Convex Across-slope shape:Linear, convex Hydric soil rating: No Leicester, very stony Percent of map unit:2 percent Landform:Drainageways, depressions Down-slope shape:Linear Across-slope shape:Concave Hydric soil rating: Yes 711E—Charlton-Rock outcrop-Hollis complex, steep Map Unit Setting National map unit symbol: 99zn Elevation: 150 to 1,460 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 Charlton and similar soils:35 percent Rock outcrop:25 percent Hollis and similar soils:20 percent Minor components:20 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Charlton Setting Landform:Hills Landform position (two-dimensional):Backslope Landform position (three-dimensional):Side slope Down-slope shape:Linear Across-slope shape:Convex Parent material:Friable loamy eolian deposits over friable loamy basal till derived from granite and gneiss Custom Soil Resource Report 21 Typical profile H1 - 0 to 7 inches: fine sandy loam H2 - 7 to 13 inches: fine sandy loam H3 - 13 to 22 inches: gravelly fine sandy loam H4 - 22 to 60 inches: gravelly sandy loam Properties and qualities Slope:25 to 45 percent Surface area covered with cobbles, stones or boulders:2.0 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.60 to 6.00 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Moderate (about 7.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: A Ecological site: F144AY034CT - Well Drained Till Uplands Hydric soil rating: No Description of Rock Outcrop Setting Parent material:Granite and gneiss Properties and qualities Slope:25 to 45 percent Depth to restrictive feature:0 inches to lithic bedrock Runoff class: Very high Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8s Hydric soil rating: Unranked Description of Hollis Setting Landform:Hills Landform position (two-dimensional):Summit Landform position (three-dimensional):Side slope Down-slope shape:Linear Across-slope shape:Convex Parent material:Friable loamy basal till over granite and gneiss Typical profile H1 - 0 to 5 inches: fine sandy loam H2 - 5 to 19 inches: fine sandy loam H3 - 19 to 23 inches: bedrock Properties and qualities Slope:25 to 45 percent Custom Soil Resource Report 22 Surface area covered with cobbles, stones or boulders:2.0 percent Depth to restrictive feature:10 to 20 inches to lithic bedrock Drainage class:Well drained Runoff class: Very high Capacity of the most limiting layer to transmit water (Ksat):Very low to low (0.00 to 0.01 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water capacity:Very low (about 2.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 7s Hydrologic Soil Group: D Ecological site: F144AY033MA - Shallow Dry Till Uplands Hydric soil rating: No Minor Components Chatfield Percent of map unit:15 percent Hydric soil rating: No Woodbridge Percent of map unit:5 percent Hydric soil rating: No Custom Soil Resource Report 23 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix B – Test Pit Results DDTPTP15-2A15-2BTP15-2CTP15-3ATP15-3BTP15-1ATP15-1ADDDTPTP-1TPTP-2TPTP-3TPTP-4TPTP-5TPTP-6Drawn By:RevisionsScale:Date:Sheet NumberThis drawing is not intended nor shall it be used forconstruction purposes unless the signed professional seal of aregistered landscape architect, civil engineer or land surveyoremployed by The Berkshire Design Group, Inc. is affixed above.Web: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignDo not scale drawing for quantity take-offs or construction. Usewritten dimensions only. If dimensions are incomplete, contactThe Berkshire Design Group Inc. for clarification.Land SurveyingCopyright The Berkshire Design Group, Inc.This drawing and all of its contents are the express property ofThe Berkshire Design Group, Inc., and shall not be copied orused in any way without the written consent of The BerkshireDesign Group, Inc.cTim SeneyContracting, Inc.1087 Westhampton RdNorthapton, MassachusettsTPJANUARY 22, 20211"=80'CCTEST PITLOCATION PLANSCALE 1"=80'-0" (if printed full size @ 11" x 17")0160'80'40'240' Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-1 Date 1/22/2021 Time 8:30 am Weather Cloudy 30°F Location Description (See Plan) Back side of proposed house Land Use Woods Slope (%) 5-10% Surface Elevation at Hole 356 (±) Vegetation Mature Woods Surface Stones --- Soil Parent Material Till Landform Drumlin Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way --- Feet Wetlands 125 Feet Property Line 250 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-4 Ap Loamy Sand 10 YR 2/2 --- --- --- 5 --- Massive Friable 4-24 Bw Loamy Sand 10 YR 4/4 --- --- --- 5 --- Massive Friable 24-48 C Sandy Loam 2.5 Y 4/2 --- --- --- 10 2 Massive Firm Additional Notes: No redox observed, but weeping at 30”. Depth to Groundwater Weeping from Pit Face 30 Standing Water --- Mottling --- ESHGW Depth 30 ESHGW Elev. 353.5 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-2 Date 1/22/2021 Time 9:00 am Weather Cloudy 30°F Location Description (See Plan) Along northeast side of future driveway Land Use Woods Slope (%) 2-5% Surface Elevation at Hole 352 (±) Vegetation Mature Woods Surface Stones --- Soil Parent Material Till Landform Drumlin Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way --- Feet Wetlands 100 Feet Property Line 130 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-6 Ap Loamy Sand 10 YR 2/2 --- --- --- --- --- Massive Friable 6-30 Bw Loamy Sand 10 YR 4/6 --- --- --- 5 2 Massive Friable 30-42 C1 Loamy Sand 5 YR 3/4 --- --- --- 15 5 Massive Firm 42-96 C2 Sandy Loam 5 YR 4/3 --- --- --- 15 5 Massive Firm * Additional Notes: No redox observed, but weeping at 60”. *Larger cobbles Dense layer starting at 60” Depth to Groundwater Weeping from Pit Face 60 Standing Water --- Mottling --- ESHGW Depth 60 ESHGW Elev. 347 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-3 Date 1/22/2021 Time 9:45 am Weather Cloudy 30°F Location Description (See Plan) Ridge above wetlands on abutting property Land Use Woods Slope (%) 0-2 Surface Elevation at Hole 338 (±) Vegetation Mature Woods Surface Stones --- Soil Parent Material Till Landform Drumlin Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way --- Feet Wetlands 110 Feet Property Line 200 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☒ Yes ☐ No If Yes: ☐ Disturbed Soil/Fill ☒ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones Additional Notes: Refusal & weeping at 24” depth. Depth to Groundwater Weeping from Pit Face 24 Standing Water 24 Mottling --- ESHGW Depth 24 ESHGW Elev. 336 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-4 Date 1/22/2021 Time 10:00 am Weather Cloudy 35°F Location Description (See Plan) Approx. 40’ upslope from TP-3 Land Use Woods Slope (%) 2-5% Surface Elevation at Hole 343 (±) Vegetation Mature Woods Surface Stones --- Soil Parent Material Till Landform Drumlin Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way --- Feet Wetlands 80 Feet Property Line 230 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-6 Ap Loamy Sand 10 YR 2/2 --- --- --- --- --- Massive Friable 6-24 Bw Loamy Sand 10 YR 4/6 --- --- --- 10 2 Massive Friable 24-84 C1 Loamy Sand 5 YR 3/4 --- --- --- 15 5 Massive Firm * Additional Notes: *C layer becomes denser with depth Depth to Groundwater Weeping from Pit Face 30 Standing Water --- Mottling --- ESHGW Depth 30 ESHGW Elev. 343 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-5 Date 1/22/2021 Time 11:00 am Weather Cloudy 40°F Location Description (See Plan) At edge of woods line near Rt. 66 Land Use Field Slope (%) 0-2% Surface Elevation at Hole 310 Vegetation Grasses Surface Stones --- Soil Parent Material Outwash Landform Outwash Plain Position on Landscape (SU, SH, BS, FS, TS) TS Distances from: Open Water Body --- Feet Drainage way --- Feet Wetlands 50 Feet Property Line 40 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-12 Ap Loamy Sand 10 YR 3/3 --- --- --- --- --- Massive Friable 12-24 Bw Medium Sand 10 YR 3/6 --- --- --- 5 --- Single Grain Loose 24-36 C1 Medium Sand 7.5 YR 4/6 --- --- --- --- --- Single Grain Loose 36-48 C2 Fine Sand 7.5 YR 4/6 --- --- --- --- --- Single Grain Loose * Additional Notes: Soil samples retrieved with a 2” hand auger. *Soils are more saturated at 48”. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling --- ESHGW Depth 48 ESHGW Elev. 306 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 1087 Westhampton Road, Northampton, MA Performed By Chris Chamberland, PE Deep Hole Number TP-5 Date 1/22/2021 Time 12:00 am Weather Cloudy 40°F Location Description (See Plan) Survey marker T-1 UP Land Use Woods Slope (%) 0-2% Surface Elevation at Hole 321 Vegetation Trees Surface Stones --- Soil Parent Material Till Landform Outwash Plain Position on Landscape (SU, SH, BS, FS, TS) TS Distances from: Open Water Body 100 Feet Drainage way --- Feet Wetlands 50 Feet Property Line 70 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-6 Ap Sandy Loam 10 YR 2/2 --- --- --- --- --- Massive Friable 6-18 Bw Sandy Loam 10 YR 4/6 --- --- --- --- --- Massive Friable * Additional Notes: Soil samples retrieved with a 2” hand auger. *Fully saturated soils at 18” Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling --- ESHGW Depth 18 ESHGW Elev. 321 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Infiltration Test Log Site: 1087 Westhampton Road Date: 1/22/2021 Time: 9:30 am Test ID: TP-2 Weather: Cloudy, 30°F Recent Rainfall/Irrigation: <1” Snow on 1/21 Test Type: 12” Infiltrometer Infiltrometer Log Elapsed Time Cumulative Infiltration Incremental Infiltration Infiltration Rate Min Inch Inch Inch/Hr 2 0.25 0.25 5 0.5 0.25 10 0.8 0.3 15 1.1 0.3 20 1.5 0.4 25 1.7 0.2 30 2 0.3 35 2.3 0.3 Average: 3.9 Percolation Test Log Pre-Soak Start Time: Pre-Soak End Time: Time at 12”: Time at 9”: Time at 6”: Time (9” to 6”): Rate (Min./Inch): 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Infiltration Test Log Site: 1087 Westhampton Road Date: 1/22/2021 Time: 11:30 am Test ID: TP-5 Weather: Cloudy, 40°F Recent Rainfall/Irrigation: <1” Snow on 1/21 Test Type: 12” Infiltrometer Infiltrometer Log Elapsed Time Cumulative Infiltration Incremental Infiltration Infiltration Rate Min Inch Inch Inch/Hr 2 0.5 0.5 3 1 0.5 5 1.5 0.5 7 1.9 0.4 7.5 2 0.1 10 2.5 2.5 Average: 15 Percolation Test Log Pre-Soak Start Time: Pre-Soak End Time: Time at 12”: Time at 9”: Time at 6”: Time (9” to 6”): Rate (Min./Inch): 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix C – Stormwater Hydrology Calculations E1 lower common drive E2 common drive to pond E3 lower lot 4 E4 upper lot 4 1R route to route 66 wetland 1P existing detention pond SP1 Route 66 wetland SP2 bordering veg wetland - lower SP3 bordering veg wetland - upper Routing Diagram for ex cond 02-18 Prepared by Berkshire Design Group, Printed 2/18/2021 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Project Notes Rainfall events imported from "NRCS-Rain.txt" for 4213 MA Northampton Hampshire County ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.334 39 >75% Grass cover, Good, HSG A (E1) 0.491 61 >75% Grass cover, Good, HSG B (E1) 2.212 74 >75% Grass cover, Good, HSG C (E2) 1.148 78 Meadow, non-grazed, HSG D (E1) 5.397 55 Woods, Good, HSG B (E1, E3, E4) 4.740 70 Woods, Good, HSG C (E1, E3, E4) 2.273 77 Woods, Good, HSG D (E1, E3) 0.985 98 impervious off site (E1, E2) 17.580 68 TOTAL AREA ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.334 HSG A E1 5.888 HSG B E1, E3, E4 6.952 HSG C E1, E2, E3, E4 3.421 HSG D E1, E3 0.985 Other E1, E2 17.580 TOTAL AREA ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.334 0.491 2.212 0.000 0.000 3.037 >75% Grass cover, Good E1, E2 0.000 0.000 0.000 1.148 0.000 1.148 Meadow, non-grazed E1 0.000 5.397 4.740 2.273 0.000 12.410 Woods, Good E1, E3, E4 0.000 0.000 0.000 0.000 0.985 0.985 impervious off site E1, E2 0.334 5.888 6.952 3.421 0.985 17.580 TOTAL AREA ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 E2 0.00 0.00 100.0 0.0100 0.012 12.0 0.0 0.0 2 1P 360.00 359.00 10.0 0.1000 0.013 12.0 0.0 0.0 NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=264,378 sf 9.53% Impervious Runoff Depth=0.85"Subcatchment E1: lower common drive Flow Length=560' Tc=26.0 min CN=72 Runoff=3.28 cfs 0.430 af Runoff Area=114,037 sf 15.50% Impervious Runoff Depth=1.18"Subcatchment E2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=2.88 cfs 0.257 af Runoff Area=177,612 sf 0.00% Impervious Runoff Depth=0.54"Subcatchment E3: lower lot 4 Flow Length=430' Tc=25.3 min CN=65 Runoff=1.17 cfs 0.183 af Runoff Area=209,750 sf 0.00% Impervious Runoff Depth=0.36"Subcatchment E4: upper lot 4 Flow Length=635' Tc=48.4 min CN=60 Runoff=0.50 cfs 0.144 af Avg. Flow Depth=0.16' Max Vel=0.39 fps Inflow=0.94 cfs 0.239 afReach 1R: route to route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=0.85 cfs 0.239 af Peak Elev=361.74' Storage=3,388 cf Inflow=2.88 cfs 0.257 afPond 1P: existing detention pond Outflow=0.94 cfs 0.239 af Inflow=3.66 cfs 0.668 afLink SP1: Route 66 wetland Primary=3.66 cfs 0.668 af Inflow=1.17 cfs 0.183 afLink SP2: bordering veg wetland - lower Primary=1.17 cfs 0.183 af Inflow=0.50 cfs 0.144 afLink SP3: bordering veg wetland - upper Primary=0.50 cfs 0.144 af Total Runoff Area = 17.580 ac Runoff Volume = 1.014 af Average Runoff Depth = 0.69" 94.40% Pervious = 16.595 ac 5.60% Impervious = 0.985 ac NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: lower common drive Runoff = 3.28 cfs @ 12.40 hrs, Volume= 0.430 af, Depth= 0.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 25,208 98 impervious off site 14,530 39 >75% Grass cover, Good, HSG A 21,402 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 15,000 55 Woods, Good, HSG B 84,063 70 Woods, Good, HSG C 54,175 77 Woods, Good, HSG D 264,378 72 Weighted Average 239,170 90.47% Pervious Area 25,208 9.53% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment E2: common drive to pond Runoff = 2.88 cfs @ 12.22 hrs, Volume= 0.257 af, Depth= 1.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C 37,194 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 114,037 78 Weighted Average 96,357 84.50% Pervious Area 17,680 15.50% Impervious Area NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total Summary for Subcatchment E3: lower lot 4 Runoff = 1.17 cfs @ 12.42 hrs, Volume= 0.183 af, Depth= 0.54" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 51,963 70 Woods, Good, HSG C 44,846 77 Woods, Good, HSG D 80,803 55 Woods, Good, HSG B 177,612 65 Weighted Average 177,612 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.6 75 0.0900 0.08 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.1 145 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 70 0.3900 1.56 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 4.9 140 0.0360 0.47 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.3 430 Total Summary for Subcatchment E4: upper lot 4 Runoff = 0.50 cfs @ 12.89 hrs, Volume= 0.144 af, Depth= 0.36" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description 70,460 70 Woods, Good, HSG C 139,290 55 Woods, Good, HSG B 209,750 60 Weighted Average 209,750 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.4 75 0.0800 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.0 140 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 28.0 420 0.0100 0.25 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 48.4 635 Total Summary for Reach 1R: route to route 66 wetland Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth > 1.09" for 2-Year event Inflow = 0.94 cfs @ 12.58 hrs, Volume= 0.239 af Outflow = 0.85 cfs @ 13.07 hrs, Volume= 0.239 af, Atten= 10%, Lag= 29.1 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.39 fps, Min. Travel Time= 22.2 min Avg. Velocity = 0.13 fps, Avg. Travel Time= 66.4 min Peak Storage= 1,127 cf @ 13.07 hrs Average Depth at Peak Storage= 0.16' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 1.18" for 2-Year event Inflow = 2.88 cfs @ 12.22 hrs, Volume= 0.257 af Outflow = 0.94 cfs @ 12.58 hrs, Volume= 0.239 af, Atten= 67%, Lag= 21.8 min Primary = 0.94 cfs @ 12.58 hrs, Volume= 0.239 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev= 361.74' @ 12.58 hrs Surf.Area= 2,438 sf Storage= 3,388 cf Plug-Flow detention time= 99.2 min calculated for 0.239 af (93% of inflow) Center-of-Mass det. time= 61.1 min ( 931.5 - 870.3 ) Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=0.94 cfs @ 12.58 hrs HW=361.74' (Free Discharge) 1=Culvert (Passes 0.94 cfs of 4.21 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.94 cfs @ 4.79 fps) 3=Orifice/Grate ( Controls 0.00 cfs) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Link SP1: Route 66 wetland Inflow Area = 8.687 ac, 11.33% Impervious, Inflow Depth = 0.92" for 2-Year event Inflow = 3.66 cfs @ 12.42 hrs, Volume= 0.668 af Primary = 3.66 cfs @ 12.42 hrs, Volume= 0.668 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP2: bordering veg wetland - lower Inflow Area = 4.077 ac, 0.00% Impervious, Inflow Depth = 0.54" for 2-Year event Inflow = 1.17 cfs @ 12.42 hrs, Volume= 0.183 af Primary = 1.17 cfs @ 12.42 hrs, Volume= 0.183 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.815 ac, 0.00% Impervious, Inflow Depth = 0.36" for 2-Year event Inflow = 0.50 cfs @ 12.89 hrs, Volume= 0.144 af Primary = 0.50 cfs @ 12.89 hrs, Volume= 0.144 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 13HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=264,378 sf 9.53% Impervious Runoff Depth=1.80"Subcatchment E1: lower common drive Flow Length=560' Tc=26.0 min CN=72 Runoff=7.46 cfs 0.909 af Runoff Area=114,037 sf 15.50% Impervious Runoff Depth=2.27"Subcatchment E2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=5.65 cfs 0.495 af Runoff Area=177,612 sf 0.00% Impervious Runoff Depth=1.31"Subcatchment E3: lower lot 4 Flow Length=430' Tc=25.3 min CN=65 Runoff=3.50 cfs 0.446 af Runoff Area=209,750 sf 0.00% Impervious Runoff Depth=1.00"Subcatchment E4: upper lot 4 Flow Length=635' Tc=48.4 min CN=60 Runoff=2.02 cfs 0.403 af Avg. Flow Depth=0.26' Max Vel=0.55 fps Inflow=3.02 cfs 0.476 afReach 1R: route to route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=2.42 cfs 0.476 af Peak Elev=362.63' Storage=5,813 cf Inflow=5.65 cfs 0.495 afPond 1P: existing detention pond Outflow=3.02 cfs 0.476 af Inflow=9.19 cfs 1.386 afLink SP1: Route 66 wetland Primary=9.19 cfs 1.386 af Inflow=3.50 cfs 0.446 afLink SP2: bordering veg wetland - lower Primary=3.50 cfs 0.446 af Inflow=2.02 cfs 0.403 afLink SP3: bordering veg wetland - upper Primary=2.02 cfs 0.403 af Total Runoff Area = 17.580 ac Runoff Volume = 2.253 af Average Runoff Depth = 1.54" 94.40% Pervious = 16.595 ac 5.60% Impervious = 0.985 ac NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 14HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: lower common drive Runoff = 7.46 cfs @ 12.38 hrs, Volume= 0.909 af, Depth= 1.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 25,208 98 impervious off site 14,530 39 >75% Grass cover, Good, HSG A 21,402 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 15,000 55 Woods, Good, HSG B 84,063 70 Woods, Good, HSG C 54,175 77 Woods, Good, HSG D 264,378 72 Weighted Average 239,170 90.47% Pervious Area 25,208 9.53% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment E2: common drive to pond Runoff = 5.65 cfs @ 12.22 hrs, Volume= 0.495 af, Depth= 2.27" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C 37,194 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 114,037 78 Weighted Average 96,357 84.50% Pervious Area 17,680 15.50% Impervious Area NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 15HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total Summary for Subcatchment E3: lower lot 4 Runoff = 3.50 cfs @ 12.39 hrs, Volume= 0.446 af, Depth= 1.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 51,963 70 Woods, Good, HSG C 44,846 77 Woods, Good, HSG D 80,803 55 Woods, Good, HSG B 177,612 65 Weighted Average 177,612 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.6 75 0.0900 0.08 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.1 145 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 70 0.3900 1.56 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 4.9 140 0.0360 0.47 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.3 430 Total Summary for Subcatchment E4: upper lot 4 Runoff = 2.02 cfs @ 12.75 hrs, Volume= 0.403 af, Depth= 1.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 16HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description 70,460 70 Woods, Good, HSG C 139,290 55 Woods, Good, HSG B 209,750 60 Weighted Average 209,750 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.4 75 0.0800 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.0 140 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 28.0 420 0.0100 0.25 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 48.4 635 Total Summary for Reach 1R: route to route 66 wetland Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 2.18" for 10-Year event Inflow = 3.02 cfs @ 12.40 hrs, Volume= 0.476 af Outflow = 2.42 cfs @ 12.61 hrs, Volume= 0.476 af, Atten= 20%, Lag= 12.3 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.55 fps, Min. Travel Time= 16.1 min Avg. Velocity = 0.15 fps, Avg. Travel Time= 57.6 min Peak Storage= 2,329 cf @ 12.61 hrs Average Depth at Peak Storage= 0.26' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 2.27" for 10-Year event Inflow = 5.65 cfs @ 12.22 hrs, Volume= 0.495 af Outflow = 3.02 cfs @ 12.40 hrs, Volume= 0.476 af, Atten= 47%, Lag= 11.3 min Primary = 3.02 cfs @ 12.40 hrs, Volume= 0.476 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 17HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev= 362.63' @ 12.40 hrs Surf.Area= 3,032 sf Storage= 5,813 cf Plug-Flow detention time= 72.7 min calculated for 0.476 af (96% of inflow) Center-of-Mass det. time= 51.2 min ( 900.5 - 849.3 ) Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=3.02 cfs @ 12.40 hrs HW=362.63' (Free Discharge) 1=Culvert (Passes 3.02 cfs of 5.52 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.30 cfs @ 6.60 fps) 3=Orifice/Grate (Orifice Controls 1.72 cfs @ 3.16 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Link SP1: Route 66 wetland Inflow Area = 8.687 ac, 11.33% Impervious, Inflow Depth = 1.91" for 10-Year event Inflow = 9.19 cfs @ 12.42 hrs, Volume= 1.386 af Primary = 9.19 cfs @ 12.42 hrs, Volume= 1.386 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP2: bordering veg wetland - lower Inflow Area = 4.077 ac, 0.00% Impervious, Inflow Depth = 1.31" for 10-Year event Inflow = 3.50 cfs @ 12.39 hrs, Volume= 0.446 af Primary = 3.50 cfs @ 12.39 hrs, Volume= 0.446 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 18HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.815 ac, 0.00% Impervious, Inflow Depth = 1.00" for 10-Year event Inflow = 2.02 cfs @ 12.75 hrs, Volume= 0.403 af Primary = 2.02 cfs @ 12.75 hrs, Volume= 0.403 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 19HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=264,378 sf 9.53% Impervious Runoff Depth=4.41"Subcatchment E1: lower common drive Flow Length=560' Tc=26.0 min CN=72 Runoff=18.73 cfs 2.233 af Runoff Area=114,037 sf 15.50% Impervious Runoff Depth=5.10"Subcatchment E2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=12.55 cfs 1.112 af Runoff Area=177,612 sf 0.00% Impervious Runoff Depth=3.64"Subcatchment E3: lower lot 4 Flow Length=430' Tc=25.3 min CN=65 Runoff=10.45 cfs 1.236 af Runoff Area=209,750 sf 0.00% Impervious Runoff Depth=3.10"Subcatchment E4: upper lot 4 Flow Length=635' Tc=48.4 min CN=60 Runoff=7.18 cfs 1.242 af Avg. Flow Depth=0.45' Max Vel=0.79 fps Inflow=11.42 cfs 1.093 afReach 1R: route to route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=8.04 cfs 1.093 af Peak Elev=363.62' Storage=9,145 cf Inflow=12.55 cfs 1.112 afPond 1P: existing detention pond Outflow=11.42 cfs 1.093 af Inflow=26.68 cfs 3.326 afLink SP1: Route 66 wetland Primary=26.68 cfs 3.326 af Inflow=10.45 cfs 1.236 afLink SP2: bordering veg wetland - lower Primary=10.45 cfs 1.236 af Inflow=7.18 cfs 1.242 afLink SP3: bordering veg wetland - upper Primary=7.18 cfs 1.242 af Total Runoff Area = 17.580 ac Runoff Volume = 5.823 af Average Runoff Depth = 3.97" 94.40% Pervious = 16.595 ac 5.60% Impervious = 0.985 ac NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 20HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: lower common drive Runoff = 18.73 cfs @ 12.37 hrs, Volume= 2.233 af, Depth= 4.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 25,208 98 impervious off site 14,530 39 >75% Grass cover, Good, HSG A 21,402 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 15,000 55 Woods, Good, HSG B 84,063 70 Woods, Good, HSG C 54,175 77 Woods, Good, HSG D 264,378 72 Weighted Average 239,170 90.47% Pervious Area 25,208 9.53% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment E2: common drive to pond Runoff = 12.55 cfs @ 12.21 hrs, Volume= 1.112 af, Depth= 5.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C 37,194 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 114,037 78 Weighted Average 96,357 84.50% Pervious Area 17,680 15.50% Impervious Area NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 21HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total Summary for Subcatchment E3: lower lot 4 Runoff = 10.45 cfs @ 12.37 hrs, Volume= 1.236 af, Depth= 3.64" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 51,963 70 Woods, Good, HSG C 44,846 77 Woods, Good, HSG D 80,803 55 Woods, Good, HSG B 177,612 65 Weighted Average 177,612 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 16.6 75 0.0900 0.08 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.1 145 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 70 0.3900 1.56 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 4.9 140 0.0360 0.47 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.3 430 Total Summary for Subcatchment E4: upper lot 4 Runoff = 7.18 cfs @ 12.68 hrs, Volume= 1.242 af, Depth= 3.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 22HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description 70,460 70 Woods, Good, HSG C 139,290 55 Woods, Good, HSG B 209,750 60 Weighted Average 209,750 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.4 75 0.0800 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.0 140 0.1000 0.79 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 28.0 420 0.0100 0.25 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 48.4 635 Total Summary for Reach 1R: route to route 66 wetland Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 5.01" for 100-Year event Inflow = 11.42 cfs @ 12.27 hrs, Volume= 1.093 af Outflow = 8.04 cfs @ 12.40 hrs, Volume= 1.093 af, Atten= 30%, Lag= 7.5 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.79 fps, Min. Travel Time= 11.1 min Avg. Velocity = 0.18 fps, Avg. Travel Time= 47.6 min Peak Storage= 5,351 cf @ 12.40 hrs Average Depth at Peak Storage= 0.45' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 5.10" for 100-Year event Inflow = 12.55 cfs @ 12.21 hrs, Volume= 1.112 af Outflow = 11.42 cfs @ 12.27 hrs, Volume= 1.093 af, Atten= 9%, Lag= 3.8 min Primary = 11.42 cfs @ 12.27 hrs, Volume= 1.093 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 23HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev= 363.62' @ 12.27 hrs Surf.Area= 3,724 sf Storage= 9,145 cf Plug-Flow detention time= 48.7 min calculated for 1.092 af (98% of inflow) Center-of-Mass det. time= 39.2 min ( 862.8 - 823.7 ) Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=10.99 cfs @ 12.27 hrs HW=363.60' (Free Discharge) 1=Culvert (Passes 4.70 cfs of 6.66 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.60 cfs @ 8.13 fps) 3=Orifice/Grate (Orifice Controls 3.11 cfs @ 5.69 fps) 4=Broad-Crested Rectangular Weir (Weir Controls 6.29 cfs @ 1.58 fps) Summary for Link SP1: Route 66 wetland Inflow Area = 8.687 ac, 11.33% Impervious, Inflow Depth = 4.59" for 100-Year event Inflow = 26.68 cfs @ 12.38 hrs, Volume= 3.326 af Primary = 26.68 cfs @ 12.38 hrs, Volume= 3.326 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP2: bordering veg wetland - lower Inflow Area = 4.077 ac, 0.00% Impervious, Inflow Depth = 3.64" for 100-Year event Inflow = 10.45 cfs @ 12.37 hrs, Volume= 1.236 af Primary = 10.45 cfs @ 12.37 hrs, Volume= 1.236 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"ex cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 24HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.815 ac, 0.00% Impervious, Inflow Depth = 3.10" for 100-Year event Inflow = 7.18 cfs @ 12.68 hrs, Volume= 1.242 af Primary = 7.18 cfs @ 12.68 hrs, Volume= 1.242 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs P1A lower common drive P1B Lot 4 dw P2 common drive to pond P2B ex uphill of driveway below ex pond P3A ex uphill of driveway above ex pond outlet P3B driveway P3C driveway P3D P3 remaining area P4A house and driveway P4B undisturbed P4 1R route to Route 66 wetland 2R Reach through bordering wetland 3R Reach to Study Point 3 1P existing detention pond 2P infiltration pond at entrance 3P infiltration pond edge of drive 4P infiltration pond edge of drive 5P filtering rain garden SP1 Route 66 wetland SP2 bordering veg wetland - lower SP3 bordering veg wetland - upper Routing Diagram for pr cond 02-18 Prepared by Berkshire Design Group, Printed 2/18/2021 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Project Notes Rainfall events imported from "NRCS-Rain.txt" for 4213 MA Northampton Hampshire County pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.313 39 >75% Grass cover, Good, HSG A (P1A, P1B) 0.565 61 >75% Grass cover, Good, HSG B (P1A, P1B, P2B, P3C) 2.807 74 >75% Grass cover, Good, HSG C (P1B, P2, P2B, P3A, P3B, P3C, P4A, P4B) 0.025 80 >75% Grass cover, Good, HSG D (P1B, P2B) 1.148 78 Meadow, non-grazed, HSG D (P1A) 5.254 55 Woods, Good, HSG B (P1A, P1B, P2B, P3D, P4B) 3.967 70 Woods, Good, HSG C (P1A, P2B, P3A, P3D, P4B) 2.157 77 Woods, Good, HSG D (P1A, P1B, P2B, P3D) 0.019 98 driveway (P3B) 0.051 98 imperviou roof (P4A) 0.420 98 impervious (P1A) 0.136 98 impervious driveway (P1B, P3C, P4A) 0.406 98 impervious off site (P2) 0.268 98 impervious on and off site (P1B) 0.045 98 impervious roof (P4B) 17.581 69 TOTAL AREA pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.313 HSG A P1A, P1B 5.818 HSG B P1A, P1B, P2B, P3C, P3D, P4B 6.775 HSG C P1A, P1B, P2, P2B, P3A, P3B, P3C, P3D, P4A, P4B 3.329 HSG D P1A, P1B, P2B, P3D 1.345 Other P1A, P1B, P2, P3B, P3C, P4A, P4B 17.581 TOTAL AREA pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.313 0.565 2.807 0.025 0.000 3.710 >75% Grass cover, Good P1A, P1B, P2, P2B, P3A, P3B, P3C, P4A, P4B 0.000 0.000 0.000 1.148 0.000 1.148 Meadow, non-grazed P1A 0.000 5.254 3.967 2.157 0.000 11.377 Woods, Good P1A, P1B, P2B, P3A, P3D, P4B 0.000 0.000 0.000 0.000 0.019 0.019 driveway P3B 0.000 0.000 0.000 0.000 0.051 0.051 imperviou roof P4A 0.000 0.000 0.000 0.000 0.420 0.420 impervious P1A 0.000 0.000 0.000 0.000 0.136 0.136 impervious driveway P1B, P3C, P4A 0.000 0.000 0.000 0.000 0.406 0.406 impervious off site P2 0.000 0.000 0.000 0.000 0.268 0.268 impervious on and off site P1B 0.000 0.000 0.000 0.000 0.045 0.045 impervious roof P4B 0.313 5.818 6.775 3.329 1.345 17.581 TOTAL AREA pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 P2 0.00 0.00 100.0 0.0100 0.012 12.0 0.0 0.0 2 1P 360.00 359.00 10.0 0.1000 0.013 12.0 0.0 0.0 NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=215,306 sf 8.49% Impervious Runoff Depth=0.95"Subcatchment P1A: lower common drive Flow Length=560' Tc=26.0 min CN=74 Runoff=3.08 cfs 0.393 af Runoff Area=56,385 sf 25.67% Impervious Runoff Depth=0.80"Subcatchment P1B: Lot 4 dw Tc=6.0 min CN=71 Runoff=1.20 cfs 0.086 af Runoff Area=114,036 sf 15.50% Impervious Runoff Depth=1.18"Subcatchment P2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=2.88 cfs 0.257 af Runoff Area=17,845 sf 0.00% Impervious Runoff Depth=0.75"Subcatchment P2B: ex uphill of driveway Tc=6.0 min CN=70 Runoff=0.35 cfs 0.026 af Runoff Area=50,498 sf 0.00% Impervious Runoff Depth=0.80"Subcatchment P3A: ex uphill of driveway Tc=6.0 min CN=71 Runoff=1.07 cfs 0.077 af Runoff Area=3,057 sf 26.50% Impervious Runoff Depth=1.30"Subcatchment P3B: driveway Tc=6.0 min CN=80 Runoff=0.11 cfs 0.008 af Runoff Area=4,705 sf 19.43% Impervious Runoff Depth=0.95"Subcatchment P3C: driveway Tc=6.0 min CN=74 Runoff=0.12 cfs 0.009 af Runoff Area=113,020 sf 0.00% Impervious Runoff Depth=0.46"Subcatchment P3D: P3 remaining area Flow Length=375' Tc=25.7 min CN=63 Runoff=0.58 cfs 0.100 af Runoff Area=10,682 sf 41.89% Impervious Runoff Depth=1.57"Subcatchment P4A: house and driveway Tc=6.0 min CN=84 Runoff=0.47 cfs 0.032 af Runoff Area=180,289 sf 1.10% Impervious Runoff Depth=0.33"Subcatchment P4B: undisturbed P4 Flow Length=535' Tc=42.0 min CN=59 Runoff=0.39 cfs 0.113 af Avg. Flow Depth=0.17' Max Vel=0.41 fps Inflow=1.03 cfs 0.264 afReach 1R: route to Route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=0.93 cfs 0.264 af Avg. Flow Depth=0.14' Max Vel=0.42 fps Inflow=1.07 cfs 0.077 afReach 2R: Reach through bordering n=0.240 L=220.0' S=0.1091 '/' Capacity=51.99 cfs Outflow=0.75 cfs 0.077 af Avg. Flow Depth=0.06' Max Vel=0.11 fps Inflow=0.06 cfs 0.032 afReach 3R: Reach to Study Point 3 n=0.240 L=580.0' S=0.0276 '/' Capacity=26.14 cfs Outflow=0.05 cfs 0.032 af Peak Elev=361.74' Storage=3,388 cf Inflow=2.88 cfs 0.257 afPond 1P: existing detention pond Outflow=0.94 cfs 0.239 af Peak Elev=308.48' Storage=696 cf Inflow=1.20 cfs 0.086 afPond 2P: infiltration pond at entrance Discarded=0.28 cfs 0.086 af Primary=0.00 cfs 0.000 af Outflow=0.28 cfs 0.086 af Peak Elev=351.33' Storage=98 cf Inflow=0.11 cfs 0.008 afPond 3P: infiltration pond edge of drive Discarded=0.02 cfs 0.008 af Primary=0.00 cfs 0.000 af Outflow=0.02 cfs 0.008 af NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev=345.11' Storage=71 cf Inflow=0.12 cfs 0.009 afPond 4P: infiltration pond edge of drive Discarded=0.03 cfs 0.009 af Primary=0.00 cfs 0.000 af Outflow=0.03 cfs 0.009 af Peak Elev=358.59' Storage=477 cf Inflow=0.47 cfs 0.032 afPond 5P: filtering rain garden Primary=0.00 cfs 0.000 af Secondary=0.06 cfs 0.032 af Outflow=0.06 cfs 0.032 af Inflow=3.63 cfs 0.657 afLink SP1: Route 66 wetland Primary=3.63 cfs 0.657 af Inflow=1.06 cfs 0.177 afLink SP2: bordering veg wetland - lower Primary=1.06 cfs 0.177 af Inflow=0.43 cfs 0.145 afLink SP3: bordering veg wetland - upper Primary=0.43 cfs 0.145 af Total Runoff Area = 17.581 ac Runoff Volume = 1.100 af Average Runoff Depth = 0.75" 92.35% Pervious = 16.235 ac 7.65% Impervious = 1.345 ac NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1A: lower common drive Runoff = 3.08 cfs @ 12.39 hrs, Volume= 0.393 af, Depth= 0.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 18,279 98 impervious 5,750 39 >75% Grass cover, Good, HSG A 9,214 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 10,000 55 Woods, Good, HSG B 82,436 70 Woods, Good, HSG C 39,627 77 Woods, Good, HSG D 215,306 74 Weighted Average 197,027 91.51% Pervious Area 18,279 8.49% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment P1B: Lot 4 dw Runoff = 1.20 cfs @ 12.14 hrs, Volume= 0.086 af, Depth= 0.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 11,694 98 impervious on and off site 7,905 39 >75% Grass cover, Good, HSG A 12,941 61 >75% Grass cover, Good, HSG B 13,650 77 Woods, Good, HSG D 5,673 55 Woods, Good, HSG B * 2,778 98 impervious driveway 1,270 74 >75% Grass cover, Good, HSG C 474 80 >75% Grass cover, Good, HSG D 56,385 71 Weighted Average 41,913 74.33% Pervious Area 14,472 25.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: common drive to pond Runoff = 2.88 cfs @ 12.22 hrs, Volume= 0.257 af, Depth= 1.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 37,193 74 >75% Grass cover, Good, HSG C 114,036 78 Weighted Average 96,356 84.50% Pervious Area 17,680 15.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2B: ex uphill of driveway below ex pond Runoff = 0.35 cfs @ 12.14 hrs, Volume= 0.026 af, Depth= 0.75" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,437 55 Woods, Good, HSG B 12,729 70 Woods, Good, HSG C 1,879 77 Woods, Good, HSG D 600 61 >75% Grass cover, Good, HSG B 600 74 >75% Grass cover, Good, HSG C 600 80 >75% Grass cover, Good, HSG D 17,845 70 Weighted Average 17,845 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3A: ex uphill of driveway above ex pond outlet Runoff = 1.07 cfs @ 12.14 hrs, Volume= 0.077 af, Depth= 0.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 8,665 74 >75% Grass cover, Good, HSG C 41,833 70 Woods, Good, HSG C 50,498 71 Weighted Average 50,498 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3B: driveway Runoff = 0.11 cfs @ 12.13 hrs, Volume= 0.008 af, Depth= 1.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 810 98 driveway 2,247 74 >75% Grass cover, Good, HSG C 3,057 80 Weighted Average 2,247 73.50% Pervious Area 810 26.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3C: driveway Runoff = 0.12 cfs @ 12.14 hrs, Volume= 0.009 af, Depth= 0.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 914 98 impervious driveway 1,845 61 >75% Grass cover, Good, HSG B 1,946 74 >75% Grass cover, Good, HSG C 4,705 74 Weighted Average 3,791 80.57% Pervious Area 914 19.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3D: P3 remaining area Runoff = 0.58 cfs @ 12.45 hrs, Volume= 0.100 af, Depth= 0.46" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 72,650 55 Woods, Good, HSG B 1,585 70 Woods, Good, HSG C 38,785 77 Woods, Good, HSG D 113,020 63 Weighted Average 113,020 100.00% Pervious Area NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 13HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.7 75 0.0670 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.7 200 0.1300 0.90 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 3.3 100 0.0400 0.50 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.7 375 Total Summary for Subcatchment P4A: house and driveway Runoff = 0.47 cfs @ 12.13 hrs, Volume= 0.032 af, Depth= 1.57" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 2,225 98 imperviou roof 6,207 74 >75% Grass cover, Good, HSG C * 2,250 98 impervious driveway 10,682 84 Weighted Average 6,207 58.11% Pervious Area 4,475 41.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P4B: undisturbed P4 Runoff = 0.39 cfs @ 12.80 hrs, Volume= 0.113 af, Depth= 0.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 1,975 98 impervious roof 139,090 55 Woods, Good, HSG B 34,224 70 Woods, Good, HSG C 5,000 74 >75% Grass cover, Good, HSG C 180,289 59 Weighted Average 178,314 98.90% Pervious Area 1,975 1.10% Impervious Area NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 14HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 75 0.0700 0.26 Sheet Flow, Grass: Short n= 0.150 P2= 3.07" 3.5 140 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 33.7 320 0.0040 0.16 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 42.0 535 Total Summary for Reach 1R: route to Route 66 wetland Inflow Area = 3.028 ac, 13.41% Impervious, Inflow Depth > 1.05" for 2-Year event Inflow = 1.03 cfs @ 12.53 hrs, Volume= 0.264 af Outflow = 0.93 cfs @ 12.98 hrs, Volume= 0.264 af, Atten= 10%, Lag= 27.2 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.41 fps, Min. Travel Time= 21.6 min Avg. Velocity = 0.13 fps, Avg. Travel Time= 65.3 min Peak Storage= 1,197 cf @ 12.98 hrs Average Depth at Peak Storage= 0.17' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Reach 2R: Reach through bordering wetland Inflow Area = 1.337 ac, 2.96% Impervious, Inflow Depth = 0.69" for 2-Year event Inflow = 1.07 cfs @ 12.14 hrs, Volume= 0.077 af Outflow = 0.75 cfs @ 12.21 hrs, Volume= 0.077 af, Atten= 30%, Lag= 4.4 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.42 fps, Min. Travel Time= 8.7 min Avg. Velocity = 0.15 fps, Avg. Travel Time= 24.1 min Peak Storage= 388 cf @ 12.21 hrs Average Depth at Peak Storage= 0.14' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 51.99 cfs NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 15HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 220.0' Slope= 0.1091 '/' Inlet Invert= 337.00', Outlet Invert= 313.00' ‡ Summary for Reach 3R: Reach to Study Point 3 Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 1.57" for 2-Year event Inflow = 0.06 cfs @ 12.97 hrs, Volume= 0.032 af Outflow = 0.05 cfs @ 14.79 hrs, Volume= 0.032 af, Atten= 10%, Lag= 109.1 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.11 fps, Min. Travel Time= 84.4 min Avg. Velocity = 0.06 fps, Avg. Travel Time= 171.0 min Peak Storage= 251 cf @ 14.79 hrs Average Depth at Peak Storage= 0.06' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 26.14 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 580.0' Slope= 0.0276 '/' Inlet Invert= 353.00', Outlet Invert= 337.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 1.18" for 2-Year event Inflow = 2.88 cfs @ 12.22 hrs, Volume= 0.257 af Outflow = 0.94 cfs @ 12.58 hrs, Volume= 0.239 af, Atten= 67%, Lag= 21.8 min Primary = 0.94 cfs @ 12.58 hrs, Volume= 0.239 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 361.74' @ 12.58 hrs Surf.Area= 2,438 sf Storage= 3,388 cf Plug-Flow detention time= 98.0 min calculated for 0.238 af (93% of inflow) Center-of-Mass det. time= 61.1 min ( 931.5 - 870.3 ) NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 16HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=0.94 cfs @ 12.58 hrs HW=361.74' (Free Discharge) 1=Culvert (Passes 0.94 cfs of 4.21 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.94 cfs @ 4.79 fps) 3=Orifice/Grate ( Controls 0.00 cfs) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 2P: infiltration pond at entrance Inflow Area = 1.294 ac, 25.67% Impervious, Inflow Depth = 0.80" for 2-Year event Inflow = 1.20 cfs @ 12.14 hrs, Volume= 0.086 af Outflow = 0.28 cfs @ 12.54 hrs, Volume= 0.086 af, Atten= 76%, Lag= 24.1 min Discarded = 0.28 cfs @ 12.54 hrs, Volume= 0.086 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 308.48' @ 12.54 hrs Surf.Area= 1,607 sf Storage= 696 cf Plug-Flow detention time= 15.8 min calculated for 0.086 af (100% of inflow) Center-of-Mass det. time= 15.8 min ( 905.2 - 889.4 ) Volume Invert Avail.Storage Storage Description #1 308.00' 4,765 cf Custom Stage Data (Irregular) Listed below (Recalc) NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 17HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 308.00 1,325 145.0 0 0 1,325 309.00 1,950 170.0 1,627 1,627 1,971 310.00 4,500 320.0 3,137 4,765 7,825 Device Routing Invert Outlet Devices #1 Discarded 308.00'7.500 in/hr Exfiltration over Wetted area Phase-In= 0.01' #2 Primary 309.21'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 309.80'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Discarded OutFlow Max=0.28 cfs @ 12.54 hrs HW=308.48' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.28 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=308.00' (Free Discharge) 2=Orifice/Grate ( Controls 0.00 cfs) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 3P: infiltration pond edge of drive Inflow Area = 0.070 ac, 26.50% Impervious, Inflow Depth = 1.30" for 2-Year event Inflow = 0.11 cfs @ 12.13 hrs, Volume= 0.008 af Outflow = 0.02 cfs @ 12.82 hrs, Volume= 0.008 af, Atten= 86%, Lag= 41.2 min Discarded = 0.02 cfs @ 12.82 hrs, Volume= 0.008 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 351.33' @ 12.82 hrs Surf.Area= 351 sf Storage= 98 cf Plug-Flow detention time= 50.8 min calculated for 0.008 af (100% of inflow) Center-of-Mass det. time= 50.8 min ( 907.1 - 856.3 ) Volume Invert Avail.Storage Storage Description #1 351.00' 785 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) 351.00 257 72.0 0 0 257 352.00 594 97.0 414 414 604 352.50 900 110.0 371 785 824 Device Routing Invert Outlet Devices #1 Primary 352.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 18HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC #2 Discarded 351.00'1.900 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.02 cfs @ 12.82 hrs HW=351.33' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=351.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 4P: infiltration pond edge of drive Inflow Area = 0.108 ac, 19.43% Impervious, Inflow Depth = 0.95" for 2-Year event Inflow = 0.12 cfs @ 12.14 hrs, Volume= 0.009 af Outflow = 0.03 cfs @ 12.45 hrs, Volume= 0.009 af, Atten= 75%, Lag= 18.7 min Discarded = 0.03 cfs @ 12.45 hrs, Volume= 0.009 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 345.11' @ 12.45 hrs Surf.Area= 689 sf Storage= 71 cf Plug-Flow detention time= 16.0 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= 15.9 min ( 893.9 - 878.0 ) Volume Invert Avail.Storage Storage Description #1 345.00' 1,477 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) 345.00 650 90.0 0 0 650 346.00 1,067 118.0 850 850 1,125 346.50 1,450 136.0 627 1,477 1,494 Device Routing Invert Outlet Devices #1 Primary 346.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Discarded 345.00'1.900 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Discarded OutFlow Max=0.03 cfs @ 12.45 hrs HW=345.11' (Free Discharge) 2=Exfiltration ( Controls 0.03 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=345.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 19HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 5P: filtering rain garden Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 1.57" for 2-Year event Inflow = 0.47 cfs @ 12.13 hrs, Volume= 0.032 af Outflow = 0.06 cfs @ 12.97 hrs, Volume= 0.032 af, Atten= 88%, Lag= 50.4 min Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Secondary = 0.06 cfs @ 12.97 hrs, Volume= 0.032 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 358.59' @ 12.97 hrs Surf.Area= 1,037 sf Storage= 477 cf Plug-Flow detention time= 75.8 min calculated for 0.032 af (100% of inflow) Center-of-Mass det. time= 75.7 min ( 917.3 - 841.6 ) Volume Invert Avail.Storage Storage Description #1 358.00' 1,749 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) 358.00 590 110.0 0 0 590 359.00 1,413 144.0 972 972 1,289 359.50 1,700 150.0 777 1,749 1,447 Device Routing Invert Outlet Devices #1 Primary 359.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Secondary 358.00'2.410 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=358.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Secondary OutFlow Max=0.06 cfs @ 12.97 hrs HW=358.59' (Free Discharge) 2=Exfiltration ( Controls 0.06 cfs) Summary for Link SP1: Route 66 wetland Inflow Area = 9.265 ac, 12.50% Impervious, Inflow Depth = 0.85" for 2-Year event Inflow = 3.63 cfs @ 12.42 hrs, Volume= 0.657 af Primary = 3.63 cfs @ 12.42 hrs, Volume= 0.657 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 20HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP2: bordering veg wetland - lower Inflow Area = 3.932 ac, 1.01% Impervious, Inflow Depth = 0.54" for 2-Year event Inflow = 1.06 cfs @ 12.33 hrs, Volume= 0.177 af Primary = 1.06 cfs @ 12.33 hrs, Volume= 0.177 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.384 ac, 3.38% Impervious, Inflow Depth = 0.40" for 2-Year event Inflow = 0.43 cfs @ 12.81 hrs, Volume= 0.145 af Primary = 0.43 cfs @ 12.81 hrs, Volume= 0.145 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 21HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=215,306 sf 8.49% Impervious Runoff Depth=1.95"Subcatchment P1A: lower common drive Flow Length=560' Tc=26.0 min CN=74 Runoff=6.65 cfs 0.803 af Runoff Area=56,385 sf 25.67% Impervious Runoff Depth=1.72"Subcatchment P1B: Lot 4 dw Tc=6.0 min CN=71 Runoff=2.72 cfs 0.186 af Runoff Area=114,036 sf 15.50% Impervious Runoff Depth=2.27"Subcatchment P2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=5.65 cfs 0.495 af Runoff Area=17,845 sf 0.00% Impervious Runoff Depth=1.65"Subcatchment P2B: ex uphill of driveway Tc=6.0 min CN=70 Runoff=0.82 cfs 0.056 af Runoff Area=50,498 sf 0.00% Impervious Runoff Depth=1.72"Subcatchment P3A: ex uphill of driveway Tc=6.0 min CN=71 Runoff=2.44 cfs 0.167 af Runoff Area=3,057 sf 26.50% Impervious Runoff Depth=2.44"Subcatchment P3B: driveway Tc=6.0 min CN=80 Runoff=0.21 cfs 0.014 af Runoff Area=4,705 sf 19.43% Impervious Runoff Depth=1.95"Subcatchment P3C: driveway Tc=6.0 min CN=74 Runoff=0.26 cfs 0.018 af Runoff Area=113,020 sf 0.00% Impervious Runoff Depth=1.18"Subcatchment P3D: P3 remaining area Flow Length=375' Tc=25.7 min CN=63 Runoff=1.94 cfs 0.256 af Runoff Area=10,682 sf 41.89% Impervious Runoff Depth=2.79"Subcatchment P4A: house and driveway Tc=6.0 min CN=84 Runoff=0.83 cfs 0.057 af Runoff Area=180,289 sf 1.10% Impervious Runoff Depth=0.95"Subcatchment P4B: undisturbed P4 Flow Length=535' Tc=42.0 min CN=59 Runoff=1.73 cfs 0.326 af Avg. Flow Depth=0.27' Max Vel=0.56 fps Inflow=3.24 cfs 0.533 afReach 1R: route to Route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=2.71 cfs 0.533 af Avg. Flow Depth=0.22' Max Vel=0.56 fps Inflow=2.44 cfs 0.167 afReach 2R: Reach through bordering n=0.240 L=220.0' S=0.1091 '/' Capacity=51.99 cfs Outflow=1.91 cfs 0.167 af Avg. Flow Depth=0.06' Max Vel=0.13 fps Inflow=0.10 cfs 0.057 afReach 3R: Reach to Study Point 3 n=0.240 L=580.0' S=0.0276 '/' Capacity=26.14 cfs Outflow=0.07 cfs 0.057 af Peak Elev=362.63' Storage=5,813 cf Inflow=5.65 cfs 0.495 afPond 1P: existing detention pond Outflow=3.02 cfs 0.476 af Peak Elev=309.24' Storage=2,154 cf Inflow=2.72 cfs 0.186 afPond 2P: infiltration pond at entrance Discarded=0.53 cfs 0.185 af Primary=0.04 cfs 0.001 af Outflow=0.57 cfs 0.186 af Peak Elev=351.66' Storage=234 cf Inflow=0.21 cfs 0.014 afPond 3P: infiltration pond edge of drive Discarded=0.02 cfs 0.014 af Primary=0.00 cfs 0.000 af Outflow=0.02 cfs 0.014 af NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 22HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev=345.32' Storage=228 cf Inflow=0.26 cfs 0.018 afPond 4P: infiltration pond edge of drive Discarded=0.03 cfs 0.018 af Primary=0.00 cfs 0.000 af Outflow=0.03 cfs 0.018 af Peak Elev=359.01' Storage=985 cf Inflow=0.83 cfs 0.057 afPond 5P: filtering rain garden Primary=0.03 cfs 0.001 af Secondary=0.07 cfs 0.056 af Outflow=0.10 cfs 0.057 af Inflow=8.83 cfs 1.336 afLink SP1: Route 66 wetland Primary=8.83 cfs 1.336 af Inflow=3.11 cfs 0.423 afLink SP2: bordering veg wetland - lower Primary=3.11 cfs 0.423 af Inflow=1.78 cfs 0.383 afLink SP3: bordering veg wetland - upper Primary=1.78 cfs 0.383 af Total Runoff Area = 17.581 ac Runoff Volume = 2.378 af Average Runoff Depth = 1.62" 92.35% Pervious = 16.235 ac 7.65% Impervious = 1.345 ac NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 23HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1A: lower common drive Runoff = 6.65 cfs @ 12.38 hrs, Volume= 0.803 af, Depth= 1.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 18,279 98 impervious 5,750 39 >75% Grass cover, Good, HSG A 9,214 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 10,000 55 Woods, Good, HSG B 82,436 70 Woods, Good, HSG C 39,627 77 Woods, Good, HSG D 215,306 74 Weighted Average 197,027 91.51% Pervious Area 18,279 8.49% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment P1B: Lot 4 dw Runoff = 2.72 cfs @ 12.14 hrs, Volume= 0.186 af, Depth= 1.72" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 24HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 11,694 98 impervious on and off site 7,905 39 >75% Grass cover, Good, HSG A 12,941 61 >75% Grass cover, Good, HSG B 13,650 77 Woods, Good, HSG D 5,673 55 Woods, Good, HSG B * 2,778 98 impervious driveway 1,270 74 >75% Grass cover, Good, HSG C 474 80 >75% Grass cover, Good, HSG D 56,385 71 Weighted Average 41,913 74.33% Pervious Area 14,472 25.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: common drive to pond Runoff = 5.65 cfs @ 12.22 hrs, Volume= 0.495 af, Depth= 2.27" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 37,193 74 >75% Grass cover, Good, HSG C 114,036 78 Weighted Average 96,356 84.50% Pervious Area 17,680 15.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 25HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2B: ex uphill of driveway below ex pond Runoff = 0.82 cfs @ 12.14 hrs, Volume= 0.056 af, Depth= 1.65" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,437 55 Woods, Good, HSG B 12,729 70 Woods, Good, HSG C 1,879 77 Woods, Good, HSG D 600 61 >75% Grass cover, Good, HSG B 600 74 >75% Grass cover, Good, HSG C 600 80 >75% Grass cover, Good, HSG D 17,845 70 Weighted Average 17,845 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3A: ex uphill of driveway above ex pond outlet Runoff = 2.44 cfs @ 12.14 hrs, Volume= 0.167 af, Depth= 1.72" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 8,665 74 >75% Grass cover, Good, HSG C 41,833 70 Woods, Good, HSG C 50,498 71 Weighted Average 50,498 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3B: driveway Runoff = 0.21 cfs @ 12.13 hrs, Volume= 0.014 af, Depth= 2.44" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 26HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 810 98 driveway 2,247 74 >75% Grass cover, Good, HSG C 3,057 80 Weighted Average 2,247 73.50% Pervious Area 810 26.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3C: driveway Runoff = 0.26 cfs @ 12.13 hrs, Volume= 0.018 af, Depth= 1.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 914 98 impervious driveway 1,845 61 >75% Grass cover, Good, HSG B 1,946 74 >75% Grass cover, Good, HSG C 4,705 74 Weighted Average 3,791 80.57% Pervious Area 914 19.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3D: P3 remaining area Runoff = 1.94 cfs @ 12.40 hrs, Volume= 0.256 af, Depth= 1.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 72,650 55 Woods, Good, HSG B 1,585 70 Woods, Good, HSG C 38,785 77 Woods, Good, HSG D 113,020 63 Weighted Average 113,020 100.00% Pervious Area NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 27HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.7 75 0.0670 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.7 200 0.1300 0.90 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 3.3 100 0.0400 0.50 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.7 375 Total Summary for Subcatchment P4A: house and driveway Runoff = 0.83 cfs @ 12.13 hrs, Volume= 0.057 af, Depth= 2.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 2,225 98 imperviou roof 6,207 74 >75% Grass cover, Good, HSG C * 2,250 98 impervious driveway 10,682 84 Weighted Average 6,207 58.11% Pervious Area 4,475 41.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P4B: undisturbed P4 Runoff = 1.73 cfs @ 12.66 hrs, Volume= 0.326 af, Depth= 0.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 1,975 98 impervious roof 139,090 55 Woods, Good, HSG B 34,224 70 Woods, Good, HSG C 5,000 74 >75% Grass cover, Good, HSG C 180,289 59 Weighted Average 178,314 98.90% Pervious Area 1,975 1.10% Impervious Area NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 28HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 75 0.0700 0.26 Sheet Flow, Grass: Short n= 0.150 P2= 3.07" 3.5 140 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 33.7 320 0.0040 0.16 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 42.0 535 Total Summary for Reach 1R: route to Route 66 wetland Inflow Area = 3.028 ac, 13.41% Impervious, Inflow Depth = 2.11" for 10-Year event Inflow = 3.24 cfs @ 12.38 hrs, Volume= 0.533 af Outflow = 2.71 cfs @ 12.59 hrs, Volume= 0.533 af, Atten= 16%, Lag= 12.5 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.56 fps, Min. Travel Time= 15.5 min Avg. Velocity = 0.15 fps, Avg. Travel Time= 57.0 min Peak Storage= 2,517 cf @ 12.59 hrs Average Depth at Peak Storage= 0.27' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Reach 2R: Reach through bordering wetland Inflow Area = 1.337 ac, 2.96% Impervious, Inflow Depth = 1.49" for 10-Year event Inflow = 2.44 cfs @ 12.14 hrs, Volume= 0.167 af Outflow = 1.91 cfs @ 12.19 hrs, Volume= 0.167 af, Atten= 22%, Lag= 3.4 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.56 fps, Min. Travel Time= 6.5 min Avg. Velocity = 0.18 fps, Avg. Travel Time= 20.5 min Peak Storage= 743 cf @ 12.19 hrs Average Depth at Peak Storage= 0.22' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 51.99 cfs NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 29HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 220.0' Slope= 0.1091 '/' Inlet Invert= 337.00', Outlet Invert= 313.00' ‡ Summary for Reach 3R: Reach to Study Point 3 Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 2.79" for 10-Year event Inflow = 0.10 cfs @ 12.89 hrs, Volume= 0.057 af Outflow = 0.07 cfs @ 14.39 hrs, Volume= 0.057 af, Atten= 29%, Lag= 90.0 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.13 fps, Min. Travel Time= 76.0 min Avg. Velocity = 0.06 fps, Avg. Travel Time= 151.1 min Peak Storage= 319 cf @ 14.39 hrs Average Depth at Peak Storage= 0.06' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 26.14 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 580.0' Slope= 0.0276 '/' Inlet Invert= 353.00', Outlet Invert= 337.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 2.27" for 10-Year event Inflow = 5.65 cfs @ 12.22 hrs, Volume= 0.495 af Outflow = 3.02 cfs @ 12.40 hrs, Volume= 0.476 af, Atten= 47%, Lag= 11.3 min Primary = 3.02 cfs @ 12.40 hrs, Volume= 0.476 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 362.63' @ 12.40 hrs Surf.Area= 3,032 sf Storage= 5,813 cf Plug-Flow detention time= 72.7 min calculated for 0.476 af (96% of inflow) Center-of-Mass det. time= 51.2 min ( 900.5 - 849.3 ) NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 30HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=3.02 cfs @ 12.40 hrs HW=362.63' (Free Discharge) 1=Culvert (Passes 3.02 cfs of 5.52 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.30 cfs @ 6.60 fps) 3=Orifice/Grate (Orifice Controls 1.72 cfs @ 3.16 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 2P: infiltration pond at entrance Inflow Area = 1.294 ac, 25.67% Impervious, Inflow Depth = 1.72" for 10-Year event Inflow = 2.72 cfs @ 12.14 hrs, Volume= 0.186 af Outflow = 0.57 cfs @ 12.54 hrs, Volume= 0.186 af, Atten= 79%, Lag= 24.3 min Discarded = 0.53 cfs @ 12.54 hrs, Volume= 0.185 af Primary = 0.04 cfs @ 12.54 hrs, Volume= 0.001 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 309.24' @ 12.54 hrs Surf.Area= 2,465 sf Storage= 2,154 cf Plug-Flow detention time= 41.0 min calculated for 0.186 af (100% of inflow) Center-of-Mass det. time= 40.9 min ( 904.1 - 863.1 ) Volume Invert Avail.Storage Storage Description #1 308.00' 4,765 cf Custom Stage Data (Irregular) Listed below (Recalc) NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 31HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 308.00 1,325 145.0 0 0 1,325 309.00 1,950 170.0 1,627 1,627 1,971 310.00 4,500 320.0 3,137 4,765 7,825 Device Routing Invert Outlet Devices #1 Discarded 308.00'7.500 in/hr Exfiltration over Wetted area Phase-In= 0.01' #2 Primary 309.21'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 309.80'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Discarded OutFlow Max=0.53 cfs @ 12.54 hrs HW=309.24' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.53 cfs) Primary OutFlow Max=0.04 cfs @ 12.54 hrs HW=309.24' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.04 cfs @ 0.56 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 3P: infiltration pond edge of drive Inflow Area = 0.070 ac, 26.50% Impervious, Inflow Depth = 2.44" for 10-Year event Inflow = 0.21 cfs @ 12.13 hrs, Volume= 0.014 af Outflow = 0.02 cfs @ 13.11 hrs, Volume= 0.014 af, Atten= 90%, Lag= 58.8 min Discarded = 0.02 cfs @ 13.11 hrs, Volume= 0.014 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 351.66' @ 13.11 hrs Surf.Area= 463 sf Storage= 234 cf Plug-Flow detention time= 106.0 min calculated for 0.014 af (100% of inflow) Center-of-Mass det. time= 106.0 min ( 942.3 - 836.3 ) Volume Invert Avail.Storage Storage Description #1 351.00' 785 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) 351.00 257 72.0 0 0 257 352.00 594 97.0 414 414 604 352.50 900 110.0 371 785 824 Device Routing Invert Outlet Devices #1 Primary 352.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 32HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC #2 Discarded 351.00'1.900 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.02 cfs @ 13.11 hrs HW=351.66' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=351.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 4P: infiltration pond edge of drive Inflow Area = 0.108 ac, 19.43% Impervious, Inflow Depth = 1.95" for 10-Year event Inflow = 0.26 cfs @ 12.13 hrs, Volume= 0.018 af Outflow = 0.03 cfs @ 12.86 hrs, Volume= 0.018 af, Atten= 86%, Lag= 43.6 min Discarded = 0.03 cfs @ 12.86 hrs, Volume= 0.018 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 345.32' @ 12.86 hrs Surf.Area= 773 sf Storage= 228 cf Plug-Flow detention time= 51.6 min calculated for 0.018 af (100% of inflow) Center-of-Mass det. time= 51.6 min ( 905.8 - 854.3 ) Volume Invert Avail.Storage Storage Description #1 345.00' 1,477 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) 345.00 650 90.0 0 0 650 346.00 1,067 118.0 850 850 1,125 346.50 1,450 136.0 627 1,477 1,494 Device Routing Invert Outlet Devices #1 Primary 346.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Discarded 345.00'1.900 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Discarded OutFlow Max=0.03 cfs @ 12.86 hrs HW=345.32' (Free Discharge) 2=Exfiltration ( Controls 0.03 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=345.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 33HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 5P: filtering rain garden Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 2.79" for 10-Year event Inflow = 0.83 cfs @ 12.13 hrs, Volume= 0.057 af Outflow = 0.10 cfs @ 12.89 hrs, Volume= 0.057 af, Atten= 88%, Lag= 45.6 min Primary = 0.03 cfs @ 12.89 hrs, Volume= 0.001 af Secondary = 0.07 cfs @ 12.89 hrs, Volume= 0.056 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 359.01' @ 12.89 hrs Surf.Area= 1,418 sf Storage= 985 cf Plug-Flow detention time= 131.5 min calculated for 0.057 af (100% of inflow) Center-of-Mass det. time= 131.4 min ( 954.8 - 823.4 ) Volume Invert Avail.Storage Storage Description #1 358.00' 1,749 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) 358.00 590 110.0 0 0 590 359.00 1,413 144.0 972 972 1,289 359.50 1,700 150.0 777 1,749 1,447 Device Routing Invert Outlet Devices #1 Primary 359.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Secondary 358.00'2.410 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Primary OutFlow Max=0.02 cfs @ 12.89 hrs HW=359.01' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.02 cfs @ 0.23 fps) Secondary OutFlow Max=0.07 cfs @ 12.89 hrs HW=359.01' (Free Discharge) 2=Exfiltration ( Controls 0.07 cfs) Summary for Link SP1: Route 66 wetland Inflow Area = 9.265 ac, 12.50% Impervious, Inflow Depth = 1.73" for 10-Year event Inflow = 8.83 cfs @ 12.42 hrs, Volume= 1.336 af Primary = 8.83 cfs @ 12.42 hrs, Volume= 1.336 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 34HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP2: bordering veg wetland - lower Inflow Area = 3.932 ac, 1.01% Impervious, Inflow Depth = 1.29" for 10-Year event Inflow = 3.11 cfs @ 12.27 hrs, Volume= 0.423 af Primary = 3.11 cfs @ 12.27 hrs, Volume= 0.423 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.384 ac, 3.38% Impervious, Inflow Depth = 1.05" for 10-Year event Inflow = 1.78 cfs @ 12.66 hrs, Volume= 0.383 af Primary = 1.78 cfs @ 12.66 hrs, Volume= 0.383 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 35HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=215,306 sf 8.49% Impervious Runoff Depth=4.64"Subcatchment P1A: lower common drive Flow Length=560' Tc=26.0 min CN=74 Runoff=16.02 cfs 1.911 af Runoff Area=56,385 sf 25.67% Impervious Runoff Depth=4.30"Subcatchment P1B: Lot 4 dw Tc=6.0 min CN=71 Runoff=6.80 cfs 0.464 af Runoff Area=114,036 sf 15.50% Impervious Runoff Depth=5.10"Subcatchment P2: common drive to pond Flow Length=625' Tc=13.4 min CN=78 Runoff=12.55 cfs 1.112 af Runoff Area=17,845 sf 0.00% Impervious Runoff Depth=4.19"Subcatchment P2B: ex uphill of driveway Tc=6.0 min CN=70 Runoff=2.10 cfs 0.143 af Runoff Area=50,498 sf 0.00% Impervious Runoff Depth=4.30"Subcatchment P3A: ex uphill of driveway Tc=6.0 min CN=71 Runoff=6.09 cfs 0.416 af Runoff Area=3,057 sf 26.50% Impervious Runoff Depth=5.33"Subcatchment P3B: driveway Tc=6.0 min CN=80 Runoff=0.44 cfs 0.031 af Runoff Area=4,705 sf 19.43% Impervious Runoff Depth=4.64"Subcatchment P3C: driveway Tc=6.0 min CN=74 Runoff=0.61 cfs 0.042 af Runoff Area=113,020 sf 0.00% Impervious Runoff Depth=3.42"Subcatchment P3D: P3 remaining area Flow Length=375' Tc=25.7 min CN=63 Runoff=6.18 cfs 0.739 af Runoff Area=10,682 sf 41.89% Impervious Runoff Depth=5.79"Subcatchment P4A: house and driveway Tc=6.0 min CN=84 Runoff=1.66 cfs 0.118 af Runoff Area=180,289 sf 1.10% Impervious Runoff Depth=2.99"Subcatchment P4B: undisturbed P4 Flow Length=535' Tc=42.0 min CN=59 Runoff=6.45 cfs 1.031 af Avg. Flow Depth=0.48' Max Vel=0.82 fps Inflow=12.26 cfs 1.236 afReach 1R: route to Route 66 wetland n=0.240 L=525.0' S=0.0800 '/' Capacity=44.52 cfs Outflow=9.11 cfs 1.236 af Avg. Flow Depth=0.35' Max Vel=0.76 fps Inflow=6.08 cfs 0.421 afReach 2R: Reach through bordering n=0.240 L=220.0' S=0.1091 '/' Capacity=51.99 cfs Outflow=5.20 cfs 0.421 af Avg. Flow Depth=0.15' Max Vel=0.22 fps Inflow=1.54 cfs 0.118 afReach 3R: Reach to Study Point 3 n=0.240 L=580.0' S=0.0276 '/' Capacity=26.14 cfs Outflow=0.41 cfs 0.118 af Peak Elev=363.62' Storage=9,145 cf Inflow=12.55 cfs 1.112 afPond 1P: existing detention pond Outflow=11.42 cfs 1.093 af Peak Elev=309.90' Storage=4,317 cf Inflow=6.80 cfs 0.464 afPond 2P: infiltration pond at entrance Discarded=1.22 cfs 0.347 af Primary=2.84 cfs 0.117 af Outflow=4.07 cfs 0.464 af Peak Elev=352.04' Storage=440 cf Inflow=0.44 cfs 0.031 afPond 3P: infiltration pond edge of drive Discarded=0.03 cfs 0.026 af Primary=0.22 cfs 0.005 af Outflow=0.24 cfs 0.031 af NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 36HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Peak Elev=345.91' Storage=757 cf Inflow=0.61 cfs 0.042 afPond 4P: infiltration pond edge of drive Discarded=0.05 cfs 0.042 af Primary=0.00 cfs 0.000 af Outflow=0.05 cfs 0.042 af Peak Elev=359.16' Storage=1,202 cf Inflow=1.66 cfs 0.118 afPond 5P: filtering rain garden Primary=1.47 cfs 0.039 af Secondary=0.08 cfs 0.079 af Outflow=1.54 cfs 0.118 af Inflow=27.09 cfs 3.264 afLink SP1: Route 66 wetland Primary=27.09 cfs 3.264 af Inflow=9.16 cfs 1.160 afLink SP2: bordering veg wetland - lower Primary=9.16 cfs 1.160 af Inflow=6.84 cfs 1.149 afLink SP3: bordering veg wetland - upper Primary=6.84 cfs 1.149 af Total Runoff Area = 17.581 ac Runoff Volume = 6.007 af Average Runoff Depth = 4.10" 92.35% Pervious = 16.235 ac 7.65% Impervious = 1.345 ac NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 37HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1A: lower common drive Runoff = 16.02 cfs @ 12.37 hrs, Volume= 1.911 af, Depth= 4.64" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 18,279 98 impervious 5,750 39 >75% Grass cover, Good, HSG A 9,214 61 >75% Grass cover, Good, HSG B 50,000 78 Meadow, non-grazed, HSG D 10,000 55 Woods, Good, HSG B 82,436 70 Woods, Good, HSG C 39,627 77 Woods, Good, HSG D 215,306 74 Weighted Average 197,027 91.51% Pervious Area 18,279 8.49% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 11.8 75 0.2100 0.11 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 0.3 20 0.2200 1.17 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 0.7 80 0.0750 1.96 2.94 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 1.5 120 0.2800 1.32 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 2.9 115 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 8.8 150 0.0130 0.29 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 26.0 560 Total Summary for Subcatchment P1B: Lot 4 dw Runoff = 6.80 cfs @ 12.13 hrs, Volume= 0.464 af, Depth= 4.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 38HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 11,694 98 impervious on and off site 7,905 39 >75% Grass cover, Good, HSG A 12,941 61 >75% Grass cover, Good, HSG B 13,650 77 Woods, Good, HSG D 5,673 55 Woods, Good, HSG B * 2,778 98 impervious driveway 1,270 74 >75% Grass cover, Good, HSG C 474 80 >75% Grass cover, Good, HSG D 56,385 71 Weighted Average 41,913 74.33% Pervious Area 14,472 25.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: common drive to pond Runoff = 12.55 cfs @ 12.21 hrs, Volume= 1.112 af, Depth= 5.10" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 15,680 98 impervious off site 59,163 74 >75% Grass cover, Good, HSG C * 2,000 98 impervious off site 37,193 74 >75% Grass cover, Good, HSG C 114,036 78 Weighted Average 96,356 84.50% Pervious Area 17,680 15.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 75 0.0900 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.07" 0.7 100 0.2000 2.24 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 0.3 100 0.0100 4.91 3.86 Pipe Channel, 12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25' n= 0.012 2.9 350 0.0800 2.02 3.03 Trap/Vee/Rect Channel Flow, Bot.W=2.00' D=0.50' Z= 2.0 '/' Top.W=4.00' n= 0.104 Riprap, 6-inch 13.4 625 Total NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 39HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2B: ex uphill of driveway below ex pond Runoff = 2.10 cfs @ 12.13 hrs, Volume= 0.143 af, Depth= 4.19" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,437 55 Woods, Good, HSG B 12,729 70 Woods, Good, HSG C 1,879 77 Woods, Good, HSG D 600 61 >75% Grass cover, Good, HSG B 600 74 >75% Grass cover, Good, HSG C 600 80 >75% Grass cover, Good, HSG D 17,845 70 Weighted Average 17,845 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3A: ex uphill of driveway above ex pond outlet Runoff = 6.09 cfs @ 12.13 hrs, Volume= 0.416 af, Depth= 4.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 8,665 74 >75% Grass cover, Good, HSG C 41,833 70 Woods, Good, HSG C 50,498 71 Weighted Average 50,498 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3B: driveway Runoff = 0.44 cfs @ 12.13 hrs, Volume= 0.031 af, Depth= 5.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 40HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area (sf) CN Description * 810 98 driveway 2,247 74 >75% Grass cover, Good, HSG C 3,057 80 Weighted Average 2,247 73.50% Pervious Area 810 26.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3C: driveway Runoff = 0.61 cfs @ 12.13 hrs, Volume= 0.042 af, Depth= 4.64" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 914 98 impervious driveway 1,845 61 >75% Grass cover, Good, HSG B 1,946 74 >75% Grass cover, Good, HSG C 4,705 74 Weighted Average 3,791 80.57% Pervious Area 914 19.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P3D: P3 remaining area Runoff = 6.18 cfs @ 12.37 hrs, Volume= 0.739 af, Depth= 3.42" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 72,650 55 Woods, Good, HSG B 1,585 70 Woods, Good, HSG C 38,785 77 Woods, Good, HSG D 113,020 63 Weighted Average 113,020 100.00% Pervious Area NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 41HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.7 75 0.0670 0.07 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 3.7 200 0.1300 0.90 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 3.3 100 0.0400 0.50 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 25.7 375 Total Summary for Subcatchment P4A: house and driveway Runoff = 1.66 cfs @ 12.13 hrs, Volume= 0.118 af, Depth= 5.79" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 2,225 98 imperviou roof 6,207 74 >75% Grass cover, Good, HSG C * 2,250 98 impervious driveway 10,682 84 Weighted Average 6,207 58.11% Pervious Area 4,475 41.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P4B: undisturbed P4 Runoff = 6.45 cfs @ 12.60 hrs, Volume= 1.031 af, Depth= 2.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 1,975 98 impervious roof 139,090 55 Woods, Good, HSG B 34,224 70 Woods, Good, HSG C 5,000 74 >75% Grass cover, Good, HSG C 180,289 59 Weighted Average 178,314 98.90% Pervious Area 1,975 1.10% Impervious Area NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 42HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 75 0.0700 0.26 Sheet Flow, Grass: Short n= 0.150 P2= 3.07" 3.5 140 0.0700 0.66 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 33.7 320 0.0040 0.16 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 42.0 535 Total Summary for Reach 1R: route to Route 66 wetland Inflow Area = 3.028 ac, 13.41% Impervious, Inflow Depth = 4.90" for 100-Year event Inflow = 12.26 cfs @ 12.27 hrs, Volume= 1.236 af Outflow = 9.11 cfs @ 12.38 hrs, Volume= 1.236 af, Atten= 26%, Lag= 6.6 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.82 fps, Min. Travel Time= 10.7 min Avg. Velocity = 0.19 fps, Avg. Travel Time= 47.2 min Peak Storage= 5,833 cf @ 12.38 hrs Average Depth at Peak Storage= 0.48' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 44.52 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 525.0' Slope= 0.0800 '/' Inlet Invert= 350.00', Outlet Invert= 308.00' ‡ Summary for Reach 2R: Reach through bordering wetland Inflow Area = 1.337 ac, 2.96% Impervious, Inflow Depth = 3.78" for 100-Year event Inflow = 6.08 cfs @ 12.13 hrs, Volume= 0.421 af Outflow = 5.20 cfs @ 12.17 hrs, Volume= 0.421 af, Atten= 14%, Lag= 2.6 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.76 fps, Min. Travel Time= 4.8 min Avg. Velocity = 0.22 fps, Avg. Travel Time= 16.7 min Peak Storage= 1,491 cf @ 12.17 hrs Average Depth at Peak Storage= 0.35' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 51.99 cfs NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 43HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 220.0' Slope= 0.1091 '/' Inlet Invert= 337.00', Outlet Invert= 313.00' ‡ Summary for Reach 3R: Reach to Study Point 3 Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 5.79" for 100-Year event Inflow = 1.54 cfs @ 12.16 hrs, Volume= 0.118 af Outflow = 0.41 cfs @ 12.43 hrs, Volume= 0.118 af, Atten= 73%, Lag= 16.0 min Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.22 fps, Min. Travel Time= 44.1 min Avg. Velocity = 0.07 fps, Avg. Travel Time= 129.1 min Peak Storage= 1,096 cf @ 12.43 hrs Average Depth at Peak Storage= 0.15' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 26.14 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.240 Sheet flow over Dense Grass Length= 580.0' Slope= 0.0276 '/' Inlet Invert= 353.00', Outlet Invert= 337.00' ‡ Summary for Pond 1P: existing detention pond Inflow Area = 2.618 ac, 15.50% Impervious, Inflow Depth = 5.10" for 100-Year event Inflow = 12.55 cfs @ 12.21 hrs, Volume= 1.112 af Outflow = 11.42 cfs @ 12.27 hrs, Volume= 1.093 af, Atten= 9%, Lag= 3.8 min Primary = 11.42 cfs @ 12.27 hrs, Volume= 1.093 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 363.62' @ 12.27 hrs Surf.Area= 3,724 sf Storage= 9,145 cf Plug-Flow detention time= 48.7 min calculated for 1.092 af (98% of inflow) Center-of-Mass det. time= 39.2 min ( 862.8 - 823.7 ) NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 44HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 360.00' 10,625 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) 360.00 1,500 144.0 0 0 1,500 361.00 2,000 169.0 1,744 1,744 2,142 362.00 2,600 192.0 2,293 4,037 2,827 363.00 3,300 216.0 2,943 6,981 3,632 364.00 4,000 240.0 3,644 10,625 4,533 Device Routing Invert Outlet Devices #1 Primary 360.00'12.0" Round Culvert L= 10.0' CMP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 360.00' / 359.00' S= 0.1000 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 360.50'6.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 362.20'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #4 Primary 363.20'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Primary OutFlow Max=10.99 cfs @ 12.27 hrs HW=363.60' (Free Discharge) 1=Culvert (Passes 4.70 cfs of 6.66 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.60 cfs @ 8.13 fps) 3=Orifice/Grate (Orifice Controls 3.11 cfs @ 5.69 fps) 4=Broad-Crested Rectangular Weir (Weir Controls 6.29 cfs @ 1.58 fps) Summary for Pond 2P: infiltration pond at entrance Inflow Area = 1.294 ac, 25.67% Impervious, Inflow Depth = 4.30" for 100-Year event Inflow = 6.80 cfs @ 12.13 hrs, Volume= 0.464 af Outflow = 4.07 cfs @ 12.22 hrs, Volume= 0.464 af, Atten= 40%, Lag= 5.4 min Discarded = 1.22 cfs @ 12.22 hrs, Volume= 0.347 af Primary = 2.84 cfs @ 12.22 hrs, Volume= 0.117 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 309.90' @ 12.22 hrs Surf.Area= 4,189 sf Storage= 4,317 cf Plug-Flow detention time= 34.5 min calculated for 0.464 af (100% of inflow) Center-of-Mass det. time= 34.4 min ( 868.3 - 833.9 ) Volume Invert Avail.Storage Storage Description #1 308.00' 4,765 cf Custom Stage Data (Irregular) Listed below (Recalc) NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 45HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 308.00 1,325 145.0 0 0 1,325 309.00 1,950 170.0 1,627 1,627 1,971 310.00 4,500 320.0 3,137 4,765 7,825 Device Routing Invert Outlet Devices #1 Discarded 308.00'7.500 in/hr Exfiltration over Wetted area Phase-In= 0.01' #2 Primary 309.21'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 309.80'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Discarded OutFlow Max=1.21 cfs @ 12.22 hrs HW=309.89' (Free Discharge) 1=Exfiltration (Exfiltration Controls 1.21 cfs) Primary OutFlow Max=2.74 cfs @ 12.22 hrs HW=309.89' (Free Discharge) 2=Orifice/Grate (Orifice Controls 2.16 cfs @ 3.96 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.58 cfs @ 0.68 fps) Summary for Pond 3P: infiltration pond edge of drive Inflow Area = 0.070 ac, 26.50% Impervious, Inflow Depth = 5.33" for 100-Year event Inflow = 0.44 cfs @ 12.13 hrs, Volume= 0.031 af Outflow = 0.24 cfs @ 12.26 hrs, Volume= 0.031 af, Atten= 45%, Lag= 7.6 min Discarded = 0.03 cfs @ 12.26 hrs, Volume= 0.026 af Primary = 0.22 cfs @ 12.26 hrs, Volume= 0.005 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 352.04' @ 12.26 hrs Surf.Area= 618 sf Storage= 440 cf Plug-Flow detention time= 141.0 min calculated for 0.031 af (100% of inflow) Center-of-Mass det. time= 140.9 min ( 952.5 - 811.6 ) Volume Invert Avail.Storage Storage Description #1 351.00' 785 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) 351.00 257 72.0 0 0 257 352.00 594 97.0 414 414 604 352.50 900 110.0 371 785 824 Device Routing Invert Outlet Devices #1 Primary 352.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 46HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC #2 Discarded 351.00'1.900 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.03 cfs @ 12.26 hrs HW=352.04' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.20 cfs @ 12.26 hrs HW=352.04' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.20 cfs @ 0.48 fps) Summary for Pond 4P: infiltration pond edge of drive Inflow Area = 0.108 ac, 19.43% Impervious, Inflow Depth = 4.64" for 100-Year event Inflow = 0.61 cfs @ 12.13 hrs, Volume= 0.042 af Outflow = 0.05 cfs @ 13.37 hrs, Volume= 0.042 af, Atten= 92%, Lag= 74.2 min Discarded = 0.05 cfs @ 13.37 hrs, Volume= 0.042 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 345.91' @ 13.37 hrs Surf.Area= 1,026 sf Storage= 757 cf Plug-Flow detention time= 154.3 min calculated for 0.042 af (100% of inflow) Center-of-Mass det. time= 154.2 min ( 980.9 - 826.7 ) Volume Invert Avail.Storage Storage Description #1 345.00' 1,477 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) 345.00 650 90.0 0 0 650 346.00 1,067 118.0 850 850 1,125 346.50 1,450 136.0 627 1,477 1,494 Device Routing Invert Outlet Devices #1 Primary 346.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Discarded 345.00'1.900 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Discarded OutFlow Max=0.05 cfs @ 13.37 hrs HW=345.91' (Free Discharge) 2=Exfiltration ( Controls 0.05 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=345.00' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 47HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 5P: filtering rain garden Inflow Area = 0.245 ac, 41.89% Impervious, Inflow Depth = 5.79" for 100-Year event Inflow = 1.66 cfs @ 12.13 hrs, Volume= 0.118 af Outflow = 1.54 cfs @ 12.16 hrs, Volume= 0.118 af, Atten= 7%, Lag= 2.0 min Primary = 1.47 cfs @ 12.16 hrs, Volume= 0.039 af Secondary = 0.08 cfs @ 12.16 hrs, Volume= 0.079 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 359.16' @ 12.16 hrs Surf.Area= 1,501 sf Storage= 1,202 cf Plug-Flow detention time= 99.4 min calculated for 0.118 af (100% of inflow) Center-of-Mass det. time= 99.3 min ( 899.9 - 800.6 ) Volume Invert Avail.Storage Storage Description #1 358.00' 1,749 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) 358.00 590 110.0 0 0 590 359.00 1,413 144.0 972 972 1,289 359.50 1,700 150.0 777 1,749 1,447 Device Routing Invert Outlet Devices #1 Primary 359.00'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 #2 Secondary 358.00'2.410 in/hr Exfiltration over Wetted area Conductivity to Groundwater Elevation = 300.00' Phase-In= 0.01' Primary OutFlow Max=1.41 cfs @ 12.16 hrs HW=359.15' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 1.41 cfs @ 0.92 fps) Secondary OutFlow Max=0.08 cfs @ 12.16 hrs HW=359.15' (Free Discharge) 2=Exfiltration ( Controls 0.08 cfs) Summary for Link SP1: Route 66 wetland Inflow Area = 9.265 ac, 12.50% Impervious, Inflow Depth = 4.23" for 100-Year event Inflow = 27.09 cfs @ 12.37 hrs, Volume= 3.264 af Primary = 27.09 cfs @ 12.37 hrs, Volume= 3.264 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"pr cond 02-18 Printed 2/18/2021Prepared by Berkshire Design Group Page 48HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP2: bordering veg wetland - lower Inflow Area = 3.932 ac, 1.01% Impervious, Inflow Depth = 3.54" for 100-Year event Inflow = 9.16 cfs @ 12.24 hrs, Volume= 1.160 af Primary = 9.16 cfs @ 12.24 hrs, Volume= 1.160 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Link SP3: bordering veg wetland - upper Inflow Area = 4.384 ac, 3.38% Impervious, Inflow Depth = 3.15" for 100-Year event Inflow = 6.84 cfs @ 12.60 hrs, Volume= 1.149 af Primary = 6.84 cfs @ 12.60 hrs, Volume= 1.149 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs EIB Existing DA P1B Lot 4 dw 2P infiltration pond at entrance SP1 Route 66 wetland CB SP1p Route 66 wetland CB Routing Diagram for Sub Area 1B analysis Prepared by Berkshire Design Group, Printed 2/18/2021 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Project Notes Rainfall events imported from "NRCS-Rain.txt" for 4213 MA Northampton Hampshire County Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.262 39 >75% Grass cover, Good, HSG A (EIB, P1B) 0.115 61 >75% Grass cover, Good, HSG B (P1B) 0.011 74 >75% Grass cover, Good, HSG C (P1B) 0.313 55 Woods, Good, HSG B (EIB, P1B) 0.351 77 Woods, Good, HSG D (EIB, P1B) 0.169 98 impervious on and off site (P1B) 1.221 65 TOTAL AREA Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.262 HSG A EIB, P1B 0.427 HSG B EIB, P1B 0.011 HSG C P1B 0.351 HSG D EIB, P1B 0.169 Other P1B 1.221 TOTAL AREA Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 0.262 0.115 0.011 0.000 0.000 0.388 >75% Grass cover, Good EIB, P1B 0.000 0.313 0.000 0.351 0.000 0.664 Woods, Good EIB, P1B 0.000 0.000 0.000 0.000 0.169 0.169 impervious on and off site P1B 0.262 0.427 0.011 0.351 0.169 1.221 TOTAL AREA NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Time span=0.00-48.00 hrs, dt=0.05 hrs, 961 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Runoff Area=22,325 sf 0.00% Impervious Runoff Depth=2.88"Subcatchment EIB: Existing DA Flow Length=285' Tc=30.7 min CN=58 Runoff=0.92 cfs 0.123 af Runoff Area=30,848 sf 23.82% Impervious Runoff Depth=4.08"Subcatchment P1B: Lot 4 dw Tc=6.0 min CN=69 Runoff=3.54 cfs 0.241 af Peak Elev=309.40' Storage=2,589 cf Inflow=3.54 cfs 0.241 afPond 2P: infiltration pond at entrance Discarded=0.68 cfs 0.220 af Primary=0.73 cfs 0.021 af Outflow=1.40 cfs 0.241 af Inflow=0.92 cfs 0.123 afLink SP1: Route 66 wetland CB Primary=0.92 cfs 0.123 af Inflow=0.73 cfs 0.021 afLink SP1p: Route 66 wetland CB Primary=0.73 cfs 0.021 af Total Runoff Area = 1.221 ac Runoff Volume = 0.364 af Average Runoff Depth = 3.58" 86.18% Pervious = 1.052 ac 13.82% Impervious = 0.169 ac NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment EIB: Existing DA Runoff = 0.92 cfs @ 12.45 hrs, Volume= 0.123 af, Depth= 2.88" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 6,078 39 >75% Grass cover, Good, HSG A 7,653 77 Woods, Good, HSG D 8,594 55 Woods, Good, HSG B 22,325 58 Weighted Average 22,325 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 75 0.0400 0.05 Sheet Flow, Woods: Dense underbrush n= 0.800 P2= 3.07" 7.7 210 0.0330 0.45 Shallow Concentrated Flow, Forest w/Heavy Litter Kv= 2.5 fps 30.7 285 Total Subcatchment EIB: Existing DA Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=22,325 sf Runoff Volume=0.123 af Runoff Depth=2.88" Flow Length=285' Tc=30.7 min CN=58 0.92 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1B: Lot 4 dw Runoff = 3.54 cfs @ 12.13 hrs, Volume= 0.241 af, Depth= 4.08" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 7,349 98 impervious on and off site 5,346 39 >75% Grass cover, Good, HSG A 5,000 61 >75% Grass cover, Good, HSG B 7,658 77 Woods, Good, HSG D 5,020 55 Woods, Good, HSG B 475 74 >75% Grass cover, Good, HSG C 30,848 69 Weighted Average 23,499 76.18% Pervious Area 7,349 23.82% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Subcatchment P1B: Lot 4 dw Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=30,848 sf Runoff Volume=0.241 af Runoff Depth=4.08" Tc=6.0 min CN=69 3.54 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: infiltration pond at entrance Inflow Area = 0.708 ac, 23.82% Impervious, Inflow Depth = 4.08" for 100-Year event Inflow = 3.54 cfs @ 12.13 hrs, Volume= 0.241 af Outflow = 1.40 cfs @ 12.28 hrs, Volume= 0.241 af, Atten= 60%, Lag= 9.1 min Discarded = 0.68 cfs @ 12.28 hrs, Volume= 0.220 af Primary = 0.73 cfs @ 12.28 hrs, Volume= 0.021 af Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Peak Elev= 309.40' @ 12.28 hrs Surf.Area= 2,851 sf Storage= 2,589 cf Plug-Flow detention time= 37.4 min calculated for 0.240 af (100% of inflow) Center-of-Mass det. time= 37.4 min ( 876.0 - 838.6 ) Volume Invert Avail.Storage Storage Description #1 308.00' 4,765 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) 308.00 1,325 145.0 0 0 1,325 309.00 1,950 170.0 1,627 1,627 1,971 310.00 4,500 320.0 3,137 4,765 7,825 Device Routing Invert Outlet Devices #1 Discarded 308.00'7.500 in/hr Exfiltration over Wetted area Phase-In= 0.01' #2 Primary 309.21'10.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Primary 309.80'10.0' long x 5.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88 Discarded OutFlow Max=0.68 cfs @ 12.28 hrs HW=309.40' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.68 cfs) Primary OutFlow Max=0.72 cfs @ 12.28 hrs HW=309.40' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.72 cfs @ 1.43 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: infiltration pond at entrance Inflow Outflow Discarded Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)3 2 1 0 Inflow Area=0.708 ac Peak Elev=309.40' Storage=2,589 cf 3.54 cfs 1.40 cfs 0.68 cfs0.73 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP1: Route 66 wetland CB Inflow Area = 0.513 ac, 0.00% Impervious, Inflow Depth = 2.88" for 100-Year event Inflow = 0.92 cfs @ 12.45 hrs, Volume= 0.123 af Primary = 0.92 cfs @ 12.45 hrs, Volume= 0.123 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Link SP1: Route 66 wetland CB Inflow Primary Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Inflow Area=0.513 ac 0.92 cfs0.92 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Sub Area 1B analysis Printed 2/18/2021Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link SP1p: Route 66 wetland CB Inflow Area = 0.708 ac, 23.82% Impervious, Inflow Depth = 0.35" for 100-Year event Inflow = 0.73 cfs @ 12.28 hrs, Volume= 0.021 af Primary = 0.73 cfs @ 12.28 hrs, Volume= 0.021 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Link SP1p: Route 66 wetland CB 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=0.708 ac 0.73 cfs0.73 cfs 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix D – Groundwater Recharge Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The Berkshire Design Group, Inc. February 18, 2021 Northampton, 1087 Westhampton Road Stormwater Standard 3 – Recharge Proposed Impervious Area & Required Recharge Volume Table 1 shows the impervious area created, the soil type of the underlying soil, and the required recharge volume. Required Recharge Volume is calculated by applying the following equation: Required Recharge Volume, = × Where, = Target Depth Factor, varies – see table = Impervious Area Table 1. Proposed Impervious Area and required recharge Soil Type Impervious Area (sq. ft.) F – Target Depth Factor (in) Required Recharge Volume (cu. ft.) A 875 0.60 44 B 2,895 0.35 84 C 4,545 (driveway) 4,220 (dwelling) 0.25 0.25 95 88 D 3,185 0.10 27 Total 15,720 337 Storage Volume Provided Because of the site topography, soil types and shallow estimated high groundwater, recharge is only feasible in certain locations. Two infiltration areas have been sited within B soils along the driveway and one within the A soils at the beginning of the driveway. The rain garden is designed as a filtering rain garden given the shallow groundwater in that area. February 18, 2021 1087 Westhampton Road - Northampton Stormwater Standard 3 – Recharge Calculations Page 2 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 2 summarizes the storage volume provided for the infiltration features Table 3. Proposed Increase in Impervious Area Drainage Area (See Figure 2) Proposed Impervious Area (Ia) (sf) Stormwater practice Recharge volume P1B - driveway Sta 0+00 – 5+90 4,768 wet swale and infiltration 2,059 P3C – driveway Sta 5+90 – 6+70 914 infiltration 850 P3B – driveway Sta 6+70 – 7+40 810 infiltration 604 P4A driveway and front roofs 7+40 – 8+75 4,475 filtering rain garden 0 TOTAL 13,745 - 3,513 P4C – rear roofs 1975 disconnected downspouts - Minimum Storage Volume This analysis utilizes the “Static Method” for determining required storage volume for infiltration features. The provided infiltration storage volume of 3,513 cu. ft. exceeds the Required Recharge Volume of 337 cu. ft. The infiltration features were designed to infiltrate large storm events to mitigate for the areas which cannot be infiltrated due to topography or poor soils and high groundwater. Capture Area Adjustment The Massachusetts Stormwater Handbook requires an increase in storage capacity of infiltration features if only a portion of the site’s impervious area is tributary to the stormwater practices. At the 1087 Westhampton Road site, the house and top of driveway as well as a portion of the driveway through steep terrain are not tributary to infiltration features. 1. Required recharge volume (static): 337 cu. ft. (all impervious surfaces) 2. Impervious area draining to recharge facilities: 6,492 sq. ft. 3. Total impervious/impervious draining to facilities: 15,720/6,492 = 2.4 4. 2.4*337 = 809 cu. ft. Provided recharge of 3,513 cu. ft. > 809 cu. ft. The provided recharge exceeds the required recharge with the capture area adjustment. February 18, 2021 1087 Westhampton Road - Northampton Stormwater Standard 3 – Recharge Calculations Page 3 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The Massachusetts Stormwater Handbook requires also requires that more than 65% of the site’s impervious area cover be directed to the infiltration stormwater practices. At 1087 Westhampton Road, the existence of large areas of C and D soils and the shallow groundwater in those areas preclude infiltration. The design does direct 100% of the impervious areas within A and B soils to infiltration facilities. Drawdown Time The Massachusetts Stormwater Handbook requires that infiltration features empty in a time of less than 72 hours. The proposed infiltration features are in areas where soil evaluations have determined that in-situ soils are classified as sandy loam and loamy sand. The Rawls infiltration rates used are 1.02 inches per hour and 2.41 in/hour. 12 1.02 ℎ = 12 ℎ All infiltration practices drain in less than 72 hours. Infiltration area (See Figure 2) Maximum depth (in) Rawl’s rate Time to drain 1 Sta 0+00 15 2.41 in/hr 6 hours 2 Sta 6+00 12 1.02 in/hr 12 hours 3 Sta 7+00 12 1.02 in/hr 12 hours 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix E – Water Quality Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The Berkshire Design Group, Inc. February 18, 2021 Northampton, 1087 Westhampton Road Stormwater Standard 4 – Water Quality Volume Proposed Impervious Area Table 1 shows the proposed impervious surface areas for the proposed site. Required Water Quality Volume is calculated by applying the following equation: Required Water Quality Volume, = × Where, = Depth Factor, .5” = Impervious Area The water quality volume for the impervious area created at the site is: WQV = 0.5”* 15,720 sf/12”/ft = 655 cf. The water quality volume provided (as shown below per facility) is 4,485 cf. The volume provided by each practice is also listed. Storage volume was calculated by average end area applied to contours, as shown on the Grading & Drainage Plan. Table 1. Proposed Impervious Areas, Required and Provided WQv Drainage Area (See Figure 2) Proposed Impervious Area (Ia) (sf) WQv Required (cf) WQv provided P1B - driveway Sta 0+00 – 5+90 7,546 315 2,059 P3C – driveway Sta 5+90 – 6+70 914 38 850 P3B – driveway Sta 6+70 – 7+40 810 34 604 P4A driveway and front roofs 7+40 – 8+75 4,475 186 972 P4B – rear roofs 1975 82 0 February 18, 2021 Northampton – 1087 Westhampton Road Stormwater Standard 4 – Water Quality Volume Page 2 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 2 provides the TSS removal by drainage area. Roofs draining N/NE(1,975 sf) are not captured and not included in the calculation. A portion of the roof drains into P4B rain garden and is included in the calculation. Also note that the driveway edge includes a gravel diaphragm for pretreatment. Table 2. Proposed Impervious Areas and TSS Removal Drainage Area (See Figure 2) Proposed Impervious Area (Ia) (sf) Stormwater practice TSS Removal (%) P1B - driveway Sta 0+00 – 5+90 7,546 wet swale and infiltration 94 P3C – driveway Sta 5+90 – 6+70 914 infiltration 80 P3B – driveway Sta 6+70 – 7+40 810 infiltration 80 P4A driveway and front roofs 7+40 – 8+75 4,475 rain garden 90 TOTAL 13,745 - 91 P4B – rear roofs 1,975 Disconnected downspouts - The overall TSS removal for this site is 91 percent which meets the requirement of 80%. VINSTRUCTIONS:Version 1, Automated: Mar. 4, 20081. In BMP Column, click on Blue Cell to Activate Drop Down Menu2. Select BMP from Drop Down Menu3. After BMP is selected, TSS Removal and other Columns are automatically completed.Location: B C D E FTSS Removal Starting TSS Amount RemainingBMP1Rate1Load* Removed (C*D) Load (D-E)Water Quality Swale - Wet 0.701.00 0.70 0.30Infiltration Basin 0.800.30 0.24 0.060.000.06 0.00 0.060.000.06 0.00 0.060.000.06 0.00 0.06Total TSS Removal =94%Separate Form Needs to be Completed for Each Outlet or BMP TrainProject:1087 Westhampton RoadPrepared By:Berkshire Design Grp*Equals remaining load from previous BMP (E)Date:1/26/2021which enters the BMPLower driveway - 0+00 to 5+90TSS Removal Calculation WorksheetNon-automated TSS Calculation Sheetmust be used if Proprietary BMP Proposed1. From MassDEP Stormwater Handbook Vol. 1Mass. Dept. of Environmental Protection VINSTRUCTIONS:Version 1, Automated: Mar. 4, 20081. In BMP Column, click on Blue Cell to Activate Drop Down Menu2. Select BMP from Drop Down Menu3. After BMP is selected, TSS Removal and other Columns are automatically completed.Location: B C D E FTSS Removal Starting TSS Amount RemainingBMP1Rate1Load* Removed (C*D) Load (D-E)Infiltration Basin 0.801.00 0.80 0.200.000.20 0.00 0.200.000.20 0.00 0.200.000.20 0.00 0.200.000.20 0.00 0.20Total TSS Removal =80%Separate Form Needs to be Completed for Each Outlet or BMP TrainProject:1087 Westhampton RoadPrepared By:Berkshire Design Grp*Equals remaining load from previous BMP (E)Date:2/18/2021which enters the BMPDRIVEWAY STA 5+90 to 7+40TSS Removal Calculation WorksheetNon-automated TSS Calculation Sheetmust be used if Proprietary BMP Proposed1. From MassDEP Stormwater Handbook Vol. 1Mass. Dept. of Environmental Protection VINSTRUCTIONS:Version 1, Automated: Mar. 4, 20081. In BMP Column, click on Blue Cell to Activate Drop Down Menu2. Select BMP from Drop Down Menu3. After BMP is selected, TSS Removal and other Columns are automatically completed.Location: B C D E FTSS Removal Starting TSS Amount RemainingBMP1Rate1Load* Removed (C*D) Load (D-E)Rain Garden 0.901.00 0.90 0.100.000.10 0.00 0.100.000.10 0.00 0.100.000.10 0.00 0.100.000.10 0.00 0.10Total TSS Removal =90%Separate Form Needs to be Completed for Each Outlet or BMP TrainProject:1087 Westhampton RoadPrepared By:Berkshire Design Grp*Equals remaining load from previous BMP (E)Date:2/18/2021which enters the BMPDriveway 7+40 to 8+75TSS Removal Calculation WorksheetNon-automated TSS Calculation Sheetmust be used if Proprietary BMP Proposed1. From MassDEP Stormwater Handbook Vol. 1Mass. Dept. of Environmental Protection 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix F – Stormwater Management System – Operation & Maintenance Plan 1087 Westhampton Road February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 1 Stormwater Management System Operation & Maintenance Plan During Construction The Contractor shall be responsible for inspection and maintenance during construction. At all times, siltation fabric fencing, stakes and straw bales/wattles, sufficient to construct a sedimentation control barrier a minimum of 50 feet long, shall be stockpiled on the site in order to repair established barriers which may be damaged or breached. An inspection of all erosion control and stormwater management systems shall be conducted by the Contractor at least once a week and during all rain storms until the completion of construction. In case of any noted breach or failure, the Contractor shall immediately make appropriate repairs to any erosion control system and notify the engineer of any problems involving stormwater management systems. A rain storm shall be defined as any of the following: · A storm in which rain is predicted to last for twelve consecutive hours or more. · A storm for which a flash flood watch or warning is issued. · A single storm predicted to have a cumulative rainfall of greater than one-half inch. · A storm not meeting the previous three thresholds but which would mark a third consecutive day of measurable rainfall. The Contractor shall also inspect the erosion control and stormwater management systems at times of significant increase in surface water runoff due to rapid thawing when the risk of failure of erosion control measures is elevated. In such instances as remedial action is necessary, the Contractor shall repair any and all significant deficiencies in erosion control systems within two days. The Northampton Department of Public Works shall be notified of any significant failure of stormwater management systems or erosion and sediment control measures, and shall be notified of any release of pollutants to a water body (stream, brook, pond, etc.). The Contractor shall remove the sediment from behind the fence of the sedimentation control barrier when the accumulated sediment has reached one-half of the original installed height of the barrier. 1087 Westhampton Road February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 2 Post-Construction Stormwater Management System Owner: Timothy J. Seney 371 Prospect Street Northampton, MA 01060 Tim Seney timseney@gmail.com Party Responsible for Operation & Maintenance: Same as owner Inspection & Maintenance Schedule: 1) Stone Apron/gravel diaphragm The stone apron shall be inspected annually for sediment or debris buildup and evidence of bypassing. If debris or sediment have built up on top of the filter strip resulting in flow bypass, the sediment and debris shall be removed so that sheet flow off the driveway is restored. Sediment/debris shall be disposed of in accordance with local, state and federal guidelines and regulations. Inspections shall identify any damage or signs of erosion within and adjacent to diaphragm, which shall be repaired immediately. It is recommended that sediment/debris removal be performed after the completion of the spring snow melt. 2) Rain Garden The rain garden shall be inspected at least four times per year for sediment accumulation and signs of damage or erosion. Sediment shall be removed any time it has accumulated more than 1”. Sediment shall be removed annually, preferably during spring cleanup. At that time, sediment and the previous year’s mulch shall be removed and new mulch installed. Failure of the system to drain (ponding 48 hours after the end of the storm) shall result in inspection and cleaning. Sediments shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. It is recommended that sediment removal be performed after the completion of the spring snow melt. Inspections shall identify any damage or signs of erosion within basins or the overflow berm. Damage shall be repaired immediately. Plantings shall be maintained (weeding, clipping, mowing if applicable) yearly at a minimum. Clippings and other organic matter shall be removed from the rain garden and disposed of appropriately. 3) Infiltration Basin The infiltration basins shall be inspected at least four times per year for sediment accumulation and signs of damage or erosion. Sediment shall be removed any time it has accumulated more than 1”. Sediment shall be removed annually, preferably during spring cleanup. Failure of the system to drain (ponding 48 hours after the end of the storm) shall result in inspection and 1087 Westhampton Road February 18, 2021 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 3 cleaning. Sediments shall be removed and disposed of in accordance with local, state, and federal guidelines and regulations. It is recommended that sediment removal be performed after the completion of the spring snow melt. Inspections shall identify any damage or signs of erosion within basins or the overflow berm. Damage shall be repaired immediately. Plantings shall be maintained (weeding, clipping, mowing if applicable) yearly at a minimum. Clippings and other organic matter shall be removed from the infiltration area and disposed of appropriately. 4) Level Lip Spreader The level lip spreader shall be inspected annually for sediment buildup and evidence of bypassing. It shall be cleaned by removing and replacing stone and removing any sediment. Stone may be washed and re-used. Sediments shall be removed and disposed of in accordance with local, state, and federal guidelines and regulations. Inspections shall identify any damage or signs of erosion within and adjacent to the level lip spreader, which shall be repaired immediately. It is recommended that sediment removal, if any, be performed after the completion of the spring snow melt. 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix G – Massachusetts DEP Stormwater Checklist swchecklist.docx • 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 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. B. Stormwater Checklist and Certification swchecklist.docx • 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 LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: No disturbance to any Wetland Resource Areas Site Design Practices (e.g. clustered development, reduced frontage setbacks) Reduced Impervious Area (Redevelopment Only) Minimizing disturbance to existing trees and shrubs LID Site Design Credit Requested: Credit 1 Credit 2 Credit 3 Use of “country drainage” versus curb and gutter conveyance and pipe Bioretention Cells (includes Rain Gardens) Constructed Stormwater Wetlands (includes Gravel Wetlands designs) Treebox Filter Water Quality Swale Grass Channel Green Roof Other (describe): Standard 1: No New Untreated Discharges No new untreated discharges Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. Checklist (continued) swchecklist.docx • 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 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. Checklist (continued) swchecklist.docx • 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 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. Checklist (continued) swchecklist.docx • 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 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. Checklist (continued) swchecklist.docx • 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 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. Checklist (continued) swchecklist.docx • 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 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. 20-22 Amherst Road Pelham, Massachusetts Stormwater Management Report Berkshire Design Group Appendix H – Illicit Discharge Statement February 17, 2021 Illicit Discharge Statement The stormwater management system outlined in these plans is the system for conveying, treating, and infiltrating stormwater on site including stormwater best management practices intended to transport stormwater to the ground water. The control measures that have been included in the attached plans will be strictly followed to ensure that only storm water related discharges occur. By definition, an illicit discharge does not include discharges from the following activities or facilities: firefighting, water line flushing, landscape irrigation, uncontaminated ground water, potable water sources, foundation drains, air conditioning condensation, footing drains, individual resident car washing, flows from riparian habitats and wetlands, de-chlorinated water from swimming pools, water used for street washing and water used to clean residential buildings without detergents. Illicit discharges, if they exist currently, will be contained and eliminated in accordance with local, state and federal regulations and will be prohibited in the proposed project. Christopher Chamberland, PE for Tim Seney Contracting, Inc.