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23 Laurel Drainage report_Final Rev 07.14.202223 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 1 Table of Contents I. Introduction 2 II. Existing Conditions 2 III. Proposed Conditions 3 IV. Calculations and Design 4 V. MADEP Stormwater Standards Compliance 6 Figures Figure 1 Project Location Figure 2 Existing Hydrology Figure 3 Proposed Hydrology Appendix 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 Referenced Documents Plans: Valley Community Development – 23 Laurel Street, Northampton MA Permit drawings 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 2 Valley Community Development is proposing to develop the property at 23 Laurel Street with the construction of a 20-unit housing development, driveway and parking, sidewalks, walkways and common areas. 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 This project encompasses the 1.67-acre property at 23 Laurel Street which is currently a mixture of woods and open grass areas with a paved asphalt driveway. The project abuts Laurel Street to the west, a commercial development to the east and residential uses to the north and south. A one-way driveway with angled parking is proposed with two curb cuts onto Laurel Street. All units are planned for ADA accessibility. Overall drainage for the area is to the south where two infiltration/detention areas are proposed, one open basin and one subsurface. The project location is shown in Figure 1. Soil Data Seven test pits were dug at various locations throughout the site (see Figure 2 for locations). The test pits generally indicated fine to very fine loamy sand over fine to very fine sandy loam. Mottling indicating estimated high groundwater was observed in all test pits at relatively shallow depths ranging from 21” to 66”. The NRCS Soil Survey reports that the on-site soils consist of Hinckley loamy sand (HSG A) and Belgrade silt loam (HSG C). This conflicts somewhat with the subsurface exploration test pits where the material was found to be sandy in the upper layers and sandy loam in the lower layers. Based on the material found on site, HSG B is used in the hydrologic modeling. The NRCS Soil Report for the site is attached in Appendix A and the soil evaluation report is attached as Appendix B. Site Limits Site limits include the contributing drainage areas from the east (border of commercial parking lot) and the north (a portion of the adjacent lot). To the west and south, the property boundary is used as the drainage boundary. II. Existing Conditions An Existing Conditions Plan is shown on Figure 2. The existing site was analyzed as three drainage areas. Stormwater runoff is generally sheet flow. Drainage area E1A (0.1 acres) includes the portion of the site which currently sheet flows west to Laurel Street. Cover includes open space and wooded areas as well as a gravel apron and a small portion of the existing asphalt driveway. 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 3 Drainage area E1B (2.1 acres) includes most of the site and tributary area. Cover includes open space and wooded areas as well as the asphalt driveway and a small shed. Drainage throughout this area is from the northeast to the southwest with the low point of the site on the southwest corner adjacent to Laurel Street. Runoff has been observed at this location flowing into Laurel Street and down the curb line. Drainage area E2 (<0.1 acres) is a small portion of the site to the northeast which drains south to the adjacent lot and is currently mostly open space. III. Proposed Conditions The proposed hydrology and development are shown on Figure 3. The proposed work generally maintains existing stormwater flow patterns. The majority of the site development is directed to two stormwater facilities to the south and southwest via swales and french drains as well as piped networks. A water quality unit provides TSS removal for most of the driveway, parking and sidewalks. Area P1A (0.6 acres) to the north includes off-site contributing area comprised of open space as well as one of the proposed buildings and a walkway area. Runoff from P1A is captured in a low area and conveyed through piping to the infiltration basin. Area P1B (0.5 acres) to the north and east includes off-site contributing area and the four building roofs along the eastern site border. Runoff from P1B is conveyed to the infiltration basin with roof rain leaders and a swale/French drain on the east side. Area P1C (0.5 acres), the center of the site includes the majority of the driveway, walkways and patios. This area is directed to a Stormceptor water quality unit which discharges into the subsurface infiltration area. Area P1D (0.1 acres) includes the roofs of the buildings facing Laurel Street. These roofs are collected and conveyed to the subsurface infiltration area. Area P1E (0.2 acres) includes the site improvements in the common area (playground and pavilion), patios, and open space. This area is captured and conveyed to the infiltration basin. Area P1F (0.3 acres) includes the open space created over the subsurface system and the front yards/walkways of the units facing Laurel Street. Runoff from this area sheet flows into Laurel Street). Area P2A (<0.1 acres) is an open space area which sheet flows south to the abutter as in existing conditions. Water Quality Proposed impervious areas at the site total 32,725 sf. The proposed design provides treatment for the majority of the impervious area with a stormceptor water quality unit and two infiltration facilities. Most of the driveway and walkway surfaces are conveyed to the Stormceptor water quality unit followed by subsurface infiltration. The remaining impervious area is captured in roof leaders, connector pipes, swales and French drains and conveyed to an infiltration basin. 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 4 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 established using watershed boundaries to the north and east and parcel boundaries to the west and south. 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. For the smaller drainage areas, the site times of concentration was set to 6 minutes. The stormwater design includes two infiltration facilities. Calculations were performed for the 2-, 10-, 25-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. Table 1. Runoff Summary Table Point of Analysis 2-Year Storm 3.07” 10-Year Storm 4.47” 25-Year Storm 5.54” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing 0.27 1.48 2.71 5.63 Proposed 0.23 1.18 2.28 5.57 Runoff from the site shows a decrease in peak flow for all storms between pre and post conditions. Laurel Street Drainage System The proposed plan includes a connection to the existing Laurel Street drainage infrastructure at the beginning of this system. A stub was installed as part of the Laurel Street infrastructure project to accommodate this connection. Calculations are included to confirm that the on-site contribution to the Laurel Street system can be accommodated. The existing system in Laurel Street is comprised of two catch basins and a 15” trunk line running to the Grove Street intersection where additional catch basins connect. From there, the piped system 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 5 flows east within Grove Street. Under existing conditions, the majority of the site (drainage area E1B) drains to the corner of the property and flows as gutter flow to the catch basin at the corner of Laurel Street and Grove Street. The Laurel Street catch basins capture the uphill portion of Laurel Street up to Route 66 along with tributary areas to the east and west for a total of approximately 0.7 acres with 0.58 impervious acres. Peak flows from this drainage area are provided in Table 2. With the proposed development, stormwater runoff will be directed to the Laurel Street system rather than flowing as gutter flow to Grove Street. Calculations are provided within Table 2 to show that the Laurel Street system can accommodate the site overflows from the two site infiltration systems. The resulting peak flows are also shown in Table 2 and compared with the pipe capacity. The pipe does have the capacity to convey the existing flows and on-site overflows. Table 2. Laurel Street Storm Drain 2-Year Storm 3.07” 10-Year Storm 4.47” 25-Year Storm 5.54” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing 1.81 2.86 3.65 5.22 Proposed (from Table 1) 0.22 1.17 2.25 5.61 Total* 2.01 3.93 5.48 10.61 Pipe Capacity 11.7 11.7 11.7 11.7 *From hydroCAD model Water Quality Water quality is provided with a Stormceptor water quality unit rated at 85% TSS removal and two infiltration facilities. The Stormceptor is sited to capture the majority of the driveway and parking area as well as the majority of the walkways. Water quality volume is provided in both the infiltration facilities proportional to the tributary impervious area. The water quality volume is stored below the lowest outlet in each system and allowed to infiltrate. Overall, 94% of the site’s impervious area is tributary to the infiltration facilities. The water quality volume provided of 1,540 cf exceeds the required volume of 1,364 cf. Calculations supporting these conclusions are included in Appendix E. 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 6 Infiltration System Configuration Based on site topography and shallow groundwater present, the design is configured as two infiltration facilities with the basin elevation higher than the subsurface system. To reduce the potential for breakthrough between the two systems, low permeability material from the site will be used to build up the berm between the two systems. To evaluate the potential impacts due to groundwater mounding of these two systems, the site stormwater system was modeled assuming discharge of water exfiltrated from the basin into the subsurface system. In the 2-year storm event, peak flow rate from the site increased to 0.28 cfs. We conclude that under real life function peak flow rates would still be reduced even with interaction between these two systems. Erosion & Sedimentation Control The project plan set includes provisions for erosion control during construction. Erosion control barrier is included along Laurel Street and the southern boundary. A sediment trap with a piped outlet will be located at the corner of the southern entrance. This trap will be dewatered via a pipe under the driveway which will discharge to the new drainage manhole at the property line. Silt sacks will be installed within the manhole and catch basins on the east side of Laurel and the northeast side of Grove Street. 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 Low-impact design principles were considered during the development of the stormwater management plan for this project and have been implemented. The impervious area was limited with the use of a 16’ drive aisle and 4’ walkways throughout. An open infiltration basin is proposed for one of the stormwater features to reduce the use of plastic subsurface materials. And the stormwater facilities promote on-site infiltration of runoff to reduce the burden on the street systems and provide recharge on site. Standard 1 - Untreated Stormwater Discharge The proposed project includes a water quality unit, infiltration basin and subsurface infiltration designed to capture runoff from the additional impervious surfaces created and provide water quality treatment prior to discharge to the City system. Standard 2 - Post-Development Peak Discharge Rates The proposed stormwater improvements provide some attenuation of discharge rates such that post development discharge rates are less than pre-development peak discharge rates leaving the site. These results are discussed in detail under “Peak Runoff Rate” in Section IV, above. 23 Laurel Street June 24, 2022 – rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Page 7 Standard 3 - Recharge to Groundwater Recharge of the impervious area is provided within the proposed infiltration facilities based on the target depth factor of 0.35”. For the proposed increase in impervious area, the required recharge volume is 955 cf. The design includes capacity to recharge 1,540 cf which exceeds the required volume. Calculations of recharge are included within Appendix D. Standard 4 – Water Quality The majority of the driveway, parking area and walkways is captured by a Stormceptor water quality unit. Overall TSS removal is estimated at 85%. The water quality volume is calculated based on 0.5”. For the proposed impervious area, the required water quality volume is 1,364 cu. ft. The infiltration basins store 1,540 cf below the lowest outlet thereby providing more than the required water quality 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. Standard 6 - Protection of Critical Areas The project is not located within a critical area. Standard 7 - Redevelopment Projects The project is not a redevelopment. 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 stormwater components. Standard 10 – Prohibition of Illicit Discharges No Illicit Discharge Compliance Statement is included with this report. It will be the responsibility of the owner to submit a statement prior to the discharge of any stormwater to post-construction BMPs. 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group FIGURES PROJECTLOCATIONChecked 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 incomp lete, 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.c23 Laurel StreetNorthampton, MAWeb: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignLand SurveyingValley Community Development256 Pleasant Street, Suite ANorthampton MA 01060FIG1JUNE 24, 20221"=1,000'LCLOCUS0200010005003000CC OHWOHWOHWOHWOHWOHWOHWOHWOHWDDDSSS6" WaterWaterValve DMHRim = 184.54'WWWWWWWW8" Water Line (r)8" Water Line As MarkedGasValveGasValveUPUP 5w/LightUP 6StreetSigns"Slow Children"SignChapel StreetBituminousDrivewayBituminousApronGasValvesBit. Conc. SidewalkBit. Conc. SidewalkCBRim:184.48'Sump:179.1'WWWWWBituminous Driveway Bit. Conc SidewalkW WWWWWWWWXXXXXXXXXXXXXXXXXXGranite CurbGasTest ValveBituminous ConcreteConcreteBit. Conc. SidewalkBit. Conc.SidewalkConcreteBituminousDriveway Granite CurbGranite CurbGuyWireGranite CurbPaperBoxGranite CurbGranite CurbMailBoxWaterValveBituminousDrivewayWaterValveGranite CurbTimberBorderConcreteStairsGranite CurbGranite CurbWDDDDDBituminousDriveway Granite CurbOHWOHWOHWOHWOHWOHWOHWCOBit. ApronWWaterValvesDDWWWWWWStoneRetainingWallPeastone72871 Sq. Ft.1.673 Acres198 197196195 1 9 0 191 192 19 3194 189189 187 188 191192193190185186187188184183197195194 191 192 193 1 9 0 189 188187186185200199198197196199199198197196194195193192191190189188187186185 1841831821831821831841851871881891861 9 0 191 192193194195196198199198 StopSignCBRim:199.69'Sump:193.7'WaterValvesDMHRim:199.52'DMHRim:199.29'"32"SignLaurel StreetBituminous Concrete1" WaterBit. Conc. Sidewalk8" Water Line (r)CBRim:184.42'Sump:178.3'GuyWire182 StoneRetainingWallGranite CurbMail BoxGravelWaterValveTP-7TP-5TP-4TP-2TP-1TP-3TP-6GW192.6GW188.6GW184.4GW181.0GW182.8GW183.2GW181.2EXISTING DRAINAGE AREA BOUNDARYE-2192 Shelburne RoadE-1B23 Laurel Street andtributary area tonorthStudy PointLaurel Street andSouth Property lineE-2 23 Laurel Streetdrainage to southwoodedareaopen spaceopenspacegravelasphalt23 Laurel Street PL1 9 0 1 8 5 195 200 DMH inv in=181E-1A23 Laurel StreetSheet flowChecked 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 incomp lete, 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.c23 Laurel StreetNorthampton, MAWeb: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignLand SurveyingValley Community Development256 Pleasant Street, Suite ANorthampton MA 01060FIG2June 24, 20221"=40'GH/LCEXISTING CONDITIONSAND HYDROLOGY0804020120CC OHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWDDDWaterValveDMHRim = 184.54'GasValve GasValveStreetSigns"Slow Children"SignGasValvesCBRim:184.48'Sump:179.1'XXXXXXXXXXXXXXXXXXGasTest ValveConcreteConcrete WaterValveWaterValveTimberBorderConcreteStairsDDDDDDDDDDOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWDD WaterValvesDDDDDDStoneRetainingWallPeastone198 197196195 1 9 0 191 192 19 3194 189189 187 188 191192193190185186187188184 183197195194 191 192 193 1 9 0 189 188187186185200199198197196199198197196194195193192191190189188187186185 1841831821831821831841851871881891861 9 0 191 192193194195196198 StopSignCBRim:199.69'Sump:193.7'WaterValvesDMHRim:199.52'DMHRim:199.29'"32"SignLaurel StreetCBRim:184.42'Sump:178.3'182 StoneRetainingWallGravelWaterValveTP-7TP-5TP-4TP-2TP-1TP-3TP-6GW192.6GW188.6GW184.4GW181.0GW182.8GW183.2GW181.2 DRAINAGE AREA BOUNDARY23 Laurel Street PL19 3 DDDDDDDDDDDD D DDDDDDDDDDDDDDDDDDDDDDDDDDD D DDDDDDDDDDDD D D D D D D D D D 100' WETLAND BUFFERXXXXXXXW W D DDDDDDDDDDDDD D DDDDDDDDDDDDDDDDDDDDDDDD8 YD TOTE6'L X 6'W X 7'H 8 YD TOTE6'L X 6'W X 7'HUPUP DD DDDDDDDD D DD DDD DDD FFE=192.8FFE=191.5FFE=190.5FFE=191.5FFE=190.5FFE=192FFE=192.0FFE=194.0FFE=193.5FFE=194.5FFE=193.5x 193.5x 192.5x 193.5FFE=188.5±x188.5FFE=189.5FFE=190.5FFE=191.5H. P.186.85 x186.8 x186.8 x187.5 x187.25 xW W x185.75x187.8189 1 9 0191 191 185 1 9 0191192196195194193192 192 1 9 3 197196 1891 8 7 193 186187184188190188188 18 7 187186185189190189187.5 x 187.5 x 6" DIPR STORMCEPTORinv in = 184.44inv out = 184.2Rim = 186.7Study PointLaurel Street andSouth Property linePR SUBSURFACEINFILTRATIONCultec 150 HD40.5'x 74.5'x2.58'bottom of stone =183.5chambers=184-185.5top of stone=186PR INFILTRATIONBASINfloor = 185top of berm = 187.5inv in = 186.5P1C TO SUBSURFACEP1A TO BASINP1FTOLAURELP1B TO BASINP2TOSOUTHP1D TO SUBSURFACEP1E TO BASINPR FRENCH DRAIN/SWALEPR 10" DRAINAGE/RAIN LEADERChecked 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 incomp lete, 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.c23 Laurel StreetNorthampton, MAWeb: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignLand SurveyingValley Community Development256 Pleasant Street, Suite ANorthampton MA 01060FIG3JUNE 24, 20221"=40'LCPROPOSEDDEVELOPMENT ANDHYDROLOGY0804020120CCJULY 14, 2022 - DPW STORMWATER COMMENTS 23 Laurel Street Northampton, 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 Natural Resources Conservation Service May 9, 2022 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 220C—Boxford silt loam, 8 to 15 percent slopes........................................11 225A—Belgrade silt loam, 0 to 3 percent slopes........................................12 225B—Belgrade silt loam, 3 to 8 percent slopes........................................13 253A—Hinckley loamy sand, 0 to 3 percent slopes....................................14 253B—Hinckley loamy sand, 3 to 8 percent slopes....................................15 258A—Amostown fine sandy loam, 0 to 3 percent slopes..........................17 741A—Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes....................................................................................18 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 468664046866904686740468679046868404686890468694046866404686690468674046867904686840468689046869404686990693670 693720 693770 693820 693870 693920 693970 694020 694070 694120 694170 693670 693720 693770 693820 693870 693920 693970 694020 694070 694120 694170 42° 18' 39'' N 72° 39' 1'' W42° 18' 39'' N72° 38' 37'' W42° 18' 28'' N 72° 39' 1'' W42° 18' 28'' N 72° 38' 37'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 100 200 400 600 Feet 0 35 70 140 210 Meters Map Scale: 1:2,490 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 16, Sep 3, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 29, 2013—Oct 16, 2016 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Custom Soil Resource Report 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 220C Boxford silt loam, 8 to 15 percent slopes 8.8 26.8% 225A Belgrade silt loam, 0 to 3 percent slopes 9.5 29.0% 225B Belgrade silt loam, 3 to 8 percent slopes 2.3 7.0% 253A Hinckley loamy sand, 0 to 3 percent slopes 4.7 14.5% 253B Hinckley loamy sand, 3 to 8 percent slopes 3.7 11.1% 258A Amostown fine sandy loam, 0 to 3 percent slopes 2.7 8.2% 741A Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes 1.1 3.3% Totals for Area of Interest 32.8 100.0% 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 are identified by a special symbol on the maps. If included in the database for a Custom Soil Resource Report 9 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 220C—Boxford silt loam, 8 to 15 percent slopes Map Unit Setting National map unit symbol: 99z7 Elevation: 100 to 250 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: Farmland of statewide importance Map Unit Composition Boxford and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Boxford Setting Landform:Terraces Landform position (two-dimensional):Summit Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear Parent material:Hard silty and clayey glaciolacustrine deposits derived from granite and gneiss Typical profile H1 - 0 to 8 inches: silt loam H2 - 8 to 21 inches: silt loam H3 - 21 to 37 inches: silty clay H4 - 37 to 60 inches: silty clay Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately high (0.00 to 0.20 in/hr) Depth to water table:About 19 to 36 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 9.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: D Ecological site: F145XY006CT - Semi-Rich Moist Lake Plain Hydric soil rating: No Custom Soil Resource Report 11 Minor Components Unnamed Percent of map unit:15 percent Hydric soil rating: No 225A—Belgrade silt loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 99z3 Elevation: 110 to 540 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 Belgrade and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Belgrade Setting Landform:Terraces Landform position (two-dimensional):Summit Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Coarse-silty glaciolacustrine deposits Typical profile H1 - 0 to 10 inches: silt loam H2 - 10 to 51 inches: very fine sandy loam H3 - 51 to 60 inches: loamy very fine sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.06 to 2.00 in/hr) Depth to water table:About 18 to 42 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 10.7 inches) Interpretive groups Land capability classification (irrigated): None specified Custom Soil Resource Report 12 Land capability classification (nonirrigated): 2w Hydrologic Soil Group: C Ecological site: F145XY006CT - Semi-Rich Moist Lake Plain Hydric soil rating: No Minor Components Raynham Percent of map unit:15 percent Landform:Depressions Hydric soil rating: Yes 225B—Belgrade silt loam, 3 to 8 percent slopes Map Unit Setting National map unit symbol: 99z4 Elevation: 100 to 850 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 Belgrade and similar soils:85 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Belgrade Setting Landform:Terraces Landform position (two-dimensional):Summit Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Coarse-silty glaciolacustrine deposits Typical profile H1 - 0 to 10 inches: silt loam H2 - 10 to 51 inches: very fine sandy loam H3 - 51 to 60 inches: loamy very fine sand Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to high (0.06 to 2.00 in/hr) Depth to water table:About 18 to 42 inches Frequency of flooding:None Custom Soil Resource Report 13 Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 10.7 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: C Ecological site: F145XY006CT - Semi-Rich Moist Lake Plain Hydric soil rating: No Minor Components Raynham Percent of map unit:15 percent Landform:Depressions Hydric soil rating: Yes 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:Kame terraces, outwash deltas, outwash terraces, outwash plains Landform position (three-dimensional):Tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, 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 Custom Soil Resource Report 14 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 supply, 0 to 60 inches: Low (about 3.1 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F144AY022MA - Dry Outwash Hydric soil rating: No Minor Components Merrimac Percent of map unit:5 percent Landform:Outwash deltas, outwash terraces, kame terraces Landform position (three-dimensional):Tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, concave Hydric soil rating: No Windsor Percent of map unit:5 percent Landform:Outwash deltas, kame terraces, outwash terraces Landform position (three-dimensional):Tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, concave Hydric soil rating: No Sudbury Percent of map unit:5 percent Landform:Outwash deltas, outwash terraces, kame terraces Landform position (three-dimensional):Tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, concave Hydric soil rating: No 253B—Hinckley loamy sand, 3 to 8 percent slopes Map Unit Setting National map unit symbol: 2svm8 Custom Soil Resource Report 15 Elevation: 0 to 1,430 feet Mean annual precipitation: 36 to 53 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 250 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 deltas, outwash terraces, kames, kame terraces, moraines, eskers, outwash plains Landform position (two-dimensional):Summit, backslope, footslope, shoulder Landform position (three-dimensional):Nose slope, side slope, base slope, crest, riser, tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, 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:3 to 8 percent Depth to restrictive feature:More than 80 inches Drainage class:Excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to very high (1.42 to 99.90 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline (0.0 to 1.9 mmhos/cm) Available water supply, 0 to 60 inches: Very low (about 3.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F144AY022MA - Dry Outwash Hydric soil rating: No Minor Components Windsor Percent of map unit:8 percent Custom Soil Resource Report 16 Landform:Outwash deltas, outwash terraces, moraines, eskers, kames, outwash plains, kame terraces Landform position (two-dimensional):Summit, shoulder, backslope, footslope Landform position (three-dimensional):Nose slope, side slope, base slope, crest, riser, tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, concave Hydric soil rating: No Sudbury Percent of map unit:5 percent Landform:Outwash deltas, outwash terraces, moraines, outwash plains, kame terraces Landform position (two-dimensional):Backslope, footslope Landform position (three-dimensional):Head slope, base slope, side slope, tread Down-slope shape:Concave, linear Across-slope shape:Concave, linear Hydric soil rating: No Agawam Percent of map unit:2 percent Landform:Outwash deltas, outwash terraces, moraines, eskers, kames, outwash plains, kame terraces Landform position (two-dimensional):Summit, shoulder, backslope, footslope Landform position (three-dimensional):Nose slope, side slope, base slope, crest, riser, tread Down-slope shape:Concave, convex, linear Across-slope shape:Convex, linear, concave Hydric soil rating: No 258A—Amostown fine sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 99z0 Elevation: 110 to 280 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 Amostown and similar soils:75 percent Minor components:25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Amostown Setting Landform:Terraces, deltas, outwash plains Landform position (two-dimensional):Summit, footslope Custom Soil Resource Report 17 Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Friable sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 7 inches: fine sandy loam H2 - 7 to 32 inches: fine sandy loam H3 - 32 to 60 inches: stratified very fine sand to silt loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 9.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Ecological site: F145XY005MA - Moist Lake Plain Hydric soil rating: No Minor Components Pollux Percent of map unit:15 percent Hydric soil rating: No Agawam Percent of map unit:10 percent Hydric soil rating: No 741A—Amostown-Windsor silty substratum-Urban land complex, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 99z2 Elevation: 100 to 330 feet Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 120 to 240 days Farmland classification: Not prime farmland Custom Soil Resource Report 18 Map Unit Composition Amostown and similar soils:35 percent Windsor, silty substratum, and similar soils:25 percent Urban land:25 percent Minor components:15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Amostown Setting Landform:Terraces, outwash plains, deltas Landform position (two-dimensional):Summit, footslope Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Friable sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 7 inches: fine sandy loam H2 - 7 to 32 inches: fine sandy loam H3 - 32 to 60 inches: stratified very fine sand to silt loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table:About 18 to 36 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: High (about 9.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Ecological site: F145XY005MA - Moist Lake Plain Hydric soil rating: No Description of Windsor, Silty Substratum Setting Landform:Outwash plains Landform position (two-dimensional):Footslope Landform position (three-dimensional):Tread Down-slope shape:Convex Across-slope shape:Convex Parent material:Loose sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 8 inches: loamy sand H2 - 8 to 21 inches: loamy sand Custom Soil Resource Report 19 H3 - 21 to 45 inches: sand H4 - 45 to 60 inches: silt loam Properties and qualities Slope:0 to 3 percent Depth to restrictive feature:More than 80 inches Drainage class:Somewhat excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to 0.60 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Available water supply, 0 to 60 inches: Low (about 5.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Ecological site: F144AY022MA - Dry Outwash Hydric soil rating: No Minor Components Enosburg Percent of map unit:10 percent Landform:Terraces Hydric soil rating: Yes Maybid Percent of map unit:5 percent Landform:Depressions Hydric soil rating: Yes Custom Soil Resource Report 20 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Appendix B – Test Pit Results Laurel Street 180181182183184185186187188189190191192193 194 195196197 TP-5 TP-4 TP-3 TP-2 TP-1 TP-6 TP-7 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. 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 Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contactThe Berkshire Design Group Inc. for clarification. Land Surveying 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 orused in any way without the written consent of The Berkshire Design Group, Inc. c sĂůůĞLJ 23>ĂƵƌĞů^ƚƌĞĞƚ EŽƌƚŚĂŵƉƚŽŶ͕DĂƐƐĂĐŚƵƐĞƚƚƐ TP JUNE 30, 2021 1"=40' CC SCALE 1"=40'-0" (if printed full size @ 11" x 17") 0 80'40'20'120' TEST PIT LOCATION PLAN 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-1 Date 5/27/2021 Time 10:00 am Weather Sunny, 70°F Location Description (See Plan) Southwest corner of Lot Land Use Field/Vacant Slope (%) 0-2 Surface Elevation at Hole 184 Vegetation Grass Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 90 (Catch Basin) Feet Wetlands --- Feet Property Line 10 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 0-10 F --- --- --- --- --- --- --- --- --- --- 10-15 Ap Fine Loamy Sand 10 YR 3/3 --- --- --- --- --- Massive Friable --- 15-120 C Very Fine Loamy Sand 10 YR 3/6 42 7.5 YR 3/4 10 --- --- Massive Friable * Additional Notes: *Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 42 ESHGW Depth 42 ESHGW Elev. 180.5 184.5 181.0 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-2 Date 5/27/2021 Time 9:30 am Weather Sunny, 70°F Location Description (See Plan) Just south of woods line Land Use Field/Vacant Slope (%) 0-2 Surface Elevation at Hole 184.5 Vegetation Grass Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 50 (Catch Basin) Feet Wetlands --- Feet Property Line 25 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 0-16 Ap Fine Loamy Sand 10 YR 3/2 --- --- --- --- --- Massive Very Friable --- 16-30 C1 Fine Sand 10 YR 4/4 --- --- --- --- --- Massive Very Friable --- 30-48 C2 * 10 YR 4/2 33 5 YR 5/6 30 --- --- Massive Very Friable --- 48-108 C3 Very Fine Loamy Sand 10 YR 4/1 --- --- Massive Very Friable ** Additional Notes: *Alternating layers of fine sand and fine sandy loam. Each layer approx. 1-2” thick. **Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 42 ESHGW Depth 42 ESHGW Elev. 187.5 181.2 184.7 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-3 Date 5/27/2021 Time 10:30 am Weather Sunny, 70°F Location Description (See Plan) Near southern property line Land Use Field/Vacant Slope (%) 0-2 Surface Elevation at Hole 185 Vegetation Grass Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 120 (Catch Basin) Feet Wetlands --- Feet Property Line 20 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 Fine Loamy Sand 10 YR 3/3 --- --- --- --- --- Massive Very Friable --- 12-36 C1 Fine Loamy Sand 10 YR 4/4 --- --- --- --- --- Massive Very Friable --- 36-60 C2 * 10 YR 4/1 33 5 YR 5/6 30 --- --- Massive Very Friable --- 48-108 C3 Very Fine Loamy Sand 10 YR 3/2 --- --- Massive Very Friable ** Additional Notes: *Alternating layers of fine sand and fine sandy loam. Each layer approx. 1-2” thick. **Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 33 ESHGW Depth 33 ESHGW Elev. 182.25 182.8 185.6 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-4 Date 5/27/2021 Time 9:00 am Weather Sunny, 70°F Location Description (See Plan) South end of wooded portion of lot Land Use Woods/Vacant Slope (%) 2-5 Surface Elevation at Hole 186 Vegetation Trees/Vines (Invasives) Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 100 (Catch Basin) Feet Wetlands --- Feet Property Line 85 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 Very Fine Loamy Sand 10 YR 2/2 --- --- --- --- --- Massive Very Friable --- 12-24 C1 Very Fine Loamy Sand 10 YR 3/4 21 5 YR 3/4 30 --- --- Massive Very Friable --- 24-120 C2 Very Fine Loamy Sand 10 YR 3/2 --- --- Massive Very Friable * Additional Notes: *Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 21 ESHGW Depth 21 ESHGW Elev. 184.25 186.2 184.4 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-5 Date 5/27/2021 Time 8:30 am Weather Sunny, 70°F Location Description (See Plan) Center of wooded portion of lot Land Use Woods/Vacant Slope (%) 2-5 Surface Elevation at Hole 191 Vegetation Trees/Vines (Invasives) Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 150 (Catch Basin) Feet Wetlands --- Feet Property Line 85 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 Very Fine Loamy Sand 10 YR 3/3 --- --- --- --- --- Massive Very Friable --- 12-36 C1 Very Fine Loamy Sand 10 YR 3/4 30 5 YR 3/4 20 --- --- Massive Very Friable --- 36-120 C2 Very Fine Loamy Sand 10 YR 4/1 --- --- Massive Very Friable * Additional Notes: *Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 30 ESHGW Depth 30 ESHGW Elev. 188.5 188.6 191.1 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-6 Date 6/30/2021 Time 10:30 am Weather Sunny, 90°F Location Description (See Plan) Southeast corner of site Land Use Field/Vacant Slope (%) 0-2 Surface Elevation at Hole 188.5 Vegetation Grass Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 175 (Catch Basin) Feet Wetlands --- Feet Property Line 20 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 Fine Loamy Sand 10 YR 4/3 --- --- --- --- --- Massive Very Friable --- 12-66 C1 Fine Sand 10 YR 4/4 --- --- --- --- --- Single Grain Loose --- 66-114 C2 Fine Sandy Loam 10 YR 3/1 66 5 YR 5/3 10 --- --- Massive Very Friable * Additional Notes: *Lake bed layering of FSL and silt loam Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 66 ESHGW Depth 66 ESHGW Elev. 183 188.7 183.2 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. 23 Laurel Street, Northampton, MA Performed By Chris Chamberland P.E. Deep Hole Number TP-7 Date 6/30/2021 Time 10:30 am Weather Sunny, 90°F Location Description (See Plan) Northwest corner of site Land Use Woods/Vacant Slope (%) 2-5 Surface Elevation at Hole 195 Vegetation Trees/Vines (Invasives) Surface Stones --- Soil Parent Material Outwash Landform Glacial Lake/Floodplain Position on Landscape (SU, SH, BS, FS, TS) BS Distances from: Open Water Body --- Feet Drainage way 150 (Catch Basin) Feet Wetlands --- Feet Property Line 85 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 0-9 Ap Sandy Loam 10 YR 3/3 --- --- --- --- --- Massive Very Friable --- 9-24 Bw Sandy Loam 10 YR 3/4 27 5 YR 5/4 --- --- --- Massive Very Friable --- 24-60 C1 Very Fine Sand 10 YR 3/4 --- --- Single Grain Loose --- 60-90 C2 Sandy Loam 10 YR 4/1 --- --- Massive Very Friable * Additional Notes: *Well sorted soils with most particles near the sand/silt boundary. Depth to Groundwater Weeping from Pit Face --- Standing Water --- Mottling 30 ESHGW Depth 30 ESHGW Elev. 188.5 27 192.6 194.9 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Infiltration Test Log Site: 23 Laurel Street, Northampton, MA (TP-1) Date: 5/27/2021 Time: 10:45 am Test ID: TP-5 Weather: Sunny, 70°F Recent Rainfall/Irrigation: 0.5 inch previous day Test Type: 12” Infiltrometer Infiltrometer Log Elapsed Time Cumulative Infiltration Incremental Infiltration Infiltration Rate Min. Inch inch Inch/hr 5 0.25 0.25 3.0 10 0.5 0.25 3.0 15 0.75 0.25 3.0 20 1.0 0.25 3.0 25 1.25 0.25 3.0 30 1.5 0.25 3.0 35 1.75 0.25 3.0 Average: 3.0 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: 23 Laurel Street, Northampton, MA (TP-5) Date: 5/27/2021 Time: 8:45 am Test ID: TP-5 Weather: Sunny, 70°F Recent Rainfall/Irrigation: 0.5 inch previous day Test Type: 12” Infiltrometer Infiltrometer Log Elapsed Time Cumulative Infiltration Incremental Infiltration Infiltration Rate Min. Inch inch Inch/hr 10 0.5 0.5 3.0 16 0.875 0.375 3.8 20 1.0 0.125 1.9 25 1.25 0.25 3.0 30 1.5 0.25 3.0 Average: 3.0 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): 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Appendix C – Stormwater Hydrology Calculations E1A Laurel St direct sheet flow E1B To Laurel St bottom of site E2 To Southern Abutter LS To Laurel St Drainage System P1A Drainage to low point P1B rear of lot house roofs P1C Driveway and contributing P1D Laurel St frontage homes P1E East Site improvements P1F Overland to Laurel St P2 To Southern Abutter CPE1 Laurel St Drainage System CPP1 Laurel St Drainage System BAS Infiltration Basin CUL cultec YD yard drain at low point SP - E Total DA SP-LS Laurel Street catch basins SP-P Total DA P Routing Diagram for 23 Laurel Street FINAL rev Prepared by Berkshire Design Group, Printed 7/13/2022 HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Subcat Reach Pond Link NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 2HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment E1A: Laurel St direct sheet flow Runoff = 0.03 cfs @ 12.15 hrs, Volume= 140 cf, Depth= 0.43" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,040 61 >75% Grass cover, Good, HSG B 2,429 55 Woods, Good, HSG B * 400 96 gravel * 71 98 impervious 3,940 62 Weighted Average 3,869 98.20% Pervious Area 71 1.80% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment E1B: To Laurel St bottom of site Runoff = 0.25 cfs @ 12.32 hrs, Volume= 2,213 cf, Depth= 0.30" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 1,761 98 Roofs & Pavement 34,287 61 >75% Grass cover, Good, HSG B * 42 96 Gravel surface 53,386 55 Woods, Good, HSG B 89,476 58 Weighted Average 87,715 98.03% Pervious Area 1,761 1.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.2 520 0.0586 0.61 Lag/CN Method, Contour Length= 5,240' Interval= 1' Summary for Subcatchment E2: To Southern Abutter Runoff = 0.01 cfs @ 12.16 hrs, Volume= 53 cf, Depth= 0.36" Routed to Link SP - E : Total DA Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 3HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description 1,614 61 >75% Grass cover, Good, HSG B 164 55 Woods, Good, HSG B 1,778 60 Weighted Average 1,778 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment LS: To Laurel St Drainage System Runoff = 1.81 cfs @ 12.13 hrs, Volume= 5,519 cf, Depth= 2.14" Routed to Link SP-LS : Laurel Street catch basins Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 25,300 98 Roofs & Pavement 5,700 61 >75% Grass cover, Good, HSG B 31,000 91 Weighted Average 5,700 18.39% Pervious Area 25,300 81.61% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1A: Drainage to low point Runoff = 0.30 cfs @ 12.15 hrs, Volume= 1,100 cf, Depth= 0.54" Routed to Pond YD : yard drain at low point Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 2,870 98 Roof patio 21,600 61 >75% Grass cover, Good, HSG B * 40 98 shed 24,510 65 Weighted Average 21,600 88.13% Pervious Area 2,910 11.87% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.6 200 0.0408 0.50 Lag/CN Method, Contour Length= 1,000' Interval= 1' NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 4HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P1B: rear of lot house roofs Runoff = 0.47 cfs @ 12.16 hrs, Volume= 1,566 cf, Depth= 0.90" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 6,800 98 Roofs 700 55 Woods, Good, HSG B 13,310 61 >75% Grass cover, Good, HSG B * 50 98 shed 20,860 73 Weighted Average 14,010 67.16% Pervious Area 6,850 32.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 500 0.0815 1.06 Lag/CN Method, Contour Length= 1,700' Interval= 1' Summary for Subcatchment P1C: Driveway and contributing Runoff = 1.07 cfs @ 12.13 hrs, Volume= 3,180 cf, Depth= 1.65" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 14,280 98 impervious dw, walk, patio 8,085 61 >75% Grass cover, Good, HSG B * 800 98 future impervious 23,165 85 Weighted Average 8,085 34.90% Pervious Area 15,080 65.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1D: Laurel St frontage homes Runoff = 0.18 cfs @ 12.13 hrs, Volume= 597 cf, Depth= 2.84" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 5HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description * 2,525 98 Roofs 2,525 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1E: East Site improvements Runoff = 0.32 cfs @ 12.14 hrs, Volume= 951 cf, Depth= 1.18" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 2,160 98 Roofs & Sidewalks 5,120 61 >75% Grass cover, Good, HSG B * 1,200 98 water * 1,200 98 playground 9,680 78 Weighted Average 5,120 52.89% Pervious Area 4,560 47.11% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1F: Overland to Laurel St Runoff = 0.20 cfs @ 12.14 hrs, Volume= 664 cf, Depth= 0.62" Routed to Reach CPP1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 10,764 61 >75% Grass cover, Good, HSG B * 2,090 98 impervious 12,854 67 Weighted Average 10,764 83.74% Pervious Area 2,090 16.26% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 6HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P2: To Southern Abutter Runoff = 0.01 cfs @ 12.16 hrs, Volume= 52 cf, Depth= 0.39" Routed to Link SP-P : Total DA P Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,600 61 >75% Grass cover, Good, HSG B 1,600 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach CPE1: Laurel St Drainage System Inflow Area = 93,416 sf, 1.96% Impervious, Inflow Depth = 0.30" for 2-Year event Inflow = 0.26 cfs @ 12.31 hrs, Volume= 2,353 cf Outflow = 0.26 cfs @ 12.31 hrs, Volume= 2,353 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP - E : Total DA Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Reach CPP1: Laurel St Drainage System Inflow Area = 93,594 sf, 36.34% Impervious, Inflow Depth = 0.21" for 2-Year event Inflow = 0.23 cfs @ 12.61 hrs, Volume= 1,615 cf Outflow = 0.23 cfs @ 12.61 hrs, Volume= 1,615 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-P : Total DA P Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Pond BAS: Infiltration Basin Inflow Area = 55,050 sf, 26.01% Impervious, Inflow Depth = 0.79" for 2-Year event Inflow = 1.08 cfs @ 12.15 hrs, Volume= 3,616 cf Outflow = 0.22 cfs @ 12.67 hrs, Volume= 3,616 cf, Atten= 80%, Lag= 30.9 min Discarded = 0.07 cfs @ 12.67 hrs, Volume= 2,831 cf Primary = 0.15 cfs @ 12.67 hrs, Volume= 786 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 185.73' @ 12.67 hrs Surf.Area= 1,607 sf Storage= 1,043 cf Plug-Flow detention time= 116.0 min calculated for 3,610 cf (100% of inflow) Center-of-Mass det. time= 115.9 min ( 1,004.5 - 888.6 ) NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 7HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 185.00' 4,844 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) 185.00 1,251 177.0 0 0 1,251 186.00 1,748 210.0 1,493 1,493 2,286 187.00 2,335 194.0 2,034 3,527 2,838 187.50 2,944 212.0 1,317 4,844 3,429 Device Routing Invert Outlet Devices #1 Primary 185.50'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 186.60'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 185.00'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 183.00' Phase-In= 0.01' #4 Primary 187.25'5.0' long + 3.0 '/' SideZ x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.07 cfs @ 12.67 hrs HW=185.73' (Free Discharge) 3=Exfiltration ( Controls 0.07 cfs) Primary OutFlow Max=0.15 cfs @ 12.67 hrs HW=185.73' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.15 cfs @ 1.64 fps) 2=Orifice/Grate ( Controls 0.00 cfs) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond CUL: cultec Inflow Area = 25,690 sf, 68.53% Impervious, Inflow Depth = 1.76" for 2-Year event Inflow = 1.25 cfs @ 12.13 hrs, Volume= 3,777 cf Outflow = 0.18 cfs @ 12.69 hrs, Volume= 3,777 cf, Atten= 86%, Lag= 33.7 min Discarded = 0.14 cfs @ 12.69 hrs, Volume= 3,612 cf Primary = 0.04 cfs @ 12.69 hrs, Volume= 165 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 184.24' @ 12.69 hrs Surf.Area= 3,017 sf Storage= 1,182 cf Plug-Flow detention time= 61.0 min calculated for 3,771 cf (100% of inflow) Center-of-Mass det. time= 60.9 min ( 886.2 - 825.3 ) Volume Invert Avail.Storage Storage Description #1B 183.50' 2,146 cf 40.50'W x 74.50'L x 2.54'H Field B 7,669 cf Overall - 2,305 cf Embedded = 5,364 cf x 40.0% Voids #2B 184.00' 2,305 cf Cultec R-150XLHD x 84 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 12 rows 4,450 cf Total Available Storage NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 8HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Storage Group B created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 184.10'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 185.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 183.50'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 181.20' Phase-In= 0.01' Discarded OutFlow Max=0.14 cfs @ 12.69 hrs HW=184.24' (Free Discharge) 3=Exfiltration ( Controls 0.14 cfs) Primary OutFlow Max=0.04 cfs @ 12.69 hrs HW=184.24' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.04 cfs @ 1.25 fps) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond YD: yard drain at low point Inflow Area = 24,510 sf, 11.87% Impervious, Inflow Depth = 0.54" for 2-Year event Inflow = 0.30 cfs @ 12.15 hrs, Volume= 1,100 cf Outflow = 0.29 cfs @ 12.16 hrs, Volume= 1,100 cf, Atten= 2%, Lag= 0.6 min Primary = 0.29 cfs @ 12.16 hrs, Volume= 1,100 cf Routed to Pond BAS : Infiltration Basin Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 191.59' @ 12.16 hrs Surf.Area= 160 sf Storage= 12 cf Plug-Flow detention time= 1.1 min calculated for 1,098 cf (100% of inflow) Center-of-Mass det. time= 1.1 min ( 917.6 - 916.5 ) Volume Invert Avail.Storage Storage Description #1 191.50' 855 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) 191.50 99 35.0 0 0 99 192.00 600 135.0 157 157 1,452 193.00 800 150.0 698 855 1,821 Device Routing Invert Outlet Devices #1 Primary 191.50'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.28 cfs @ 12.16 hrs HW=191.59' (Free Discharge) 1=Orifice/Grate (Weir Controls 0.28 cfs @ 0.99 fps) NRCC 24-hr C 2-Year Rainfall=3.07"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 9HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Link SP - E: Total DA Inflow Area = 95,194 sf, 1.92% Impervious, Inflow Depth = 0.30" for 2-Year event Inflow = 0.27 cfs @ 12.31 hrs, Volume= 2,406 cf Primary = 0.27 cfs @ 12.31 hrs, Volume= 2,406 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-LS: Laurel Street catch basins Inflow Area = 126,194 sf, 47.00% Impervious, Inflow Depth = 0.68" for 2-Year event Inflow = 2.01 cfs @ 12.13 hrs, Volume= 7,186 cf Primary = 2.01 cfs @ 12.13 hrs, Volume= 7,186 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-P: Total DA P Inflow Area = 95,194 sf, 35.73% Impervious, Inflow Depth = 0.21" for 2-Year event Inflow = 0.23 cfs @ 12.60 hrs, Volume= 1,667 cf Primary = 0.23 cfs @ 12.60 hrs, Volume= 1,667 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-LS : Laurel Street catch basins Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 10HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment E1A: Laurel St direct sheet flow Runoff = 0.12 cfs @ 12.14 hrs, Volume= 369 cf, Depth= 1.12" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,040 61 >75% Grass cover, Good, HSG B 2,429 55 Woods, Good, HSG B * 400 96 gravel * 71 98 impervious 3,940 62 Weighted Average 3,869 98.20% Pervious Area 71 1.80% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment E1B: To Laurel St bottom of site Runoff = 1.39 cfs @ 12.25 hrs, Volume= 6,634 cf, Depth= 0.89" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 1,761 98 Roofs & Pavement 34,287 61 >75% Grass cover, Good, HSG B * 42 96 Gravel surface 53,386 55 Woods, Good, HSG B 89,476 58 Weighted Average 87,715 98.03% Pervious Area 1,761 1.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.2 520 0.0586 0.61 Lag/CN Method, Contour Length= 5,240' Interval= 1' Summary for Subcatchment E2: To Southern Abutter Runoff = 0.05 cfs @ 12.14 hrs, Volume= 149 cf, Depth= 1.00" Routed to Link SP - E : Total DA Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 11HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description 1,614 61 >75% Grass cover, Good, HSG B 164 55 Woods, Good, HSG B 1,778 60 Weighted Average 1,778 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment LS: To Laurel St Drainage System Runoff = 2.86 cfs @ 12.13 hrs, Volume= 8,962 cf, Depth= 3.47" Routed to Link SP-LS : Laurel Street catch basins Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 25,300 98 Roofs & Pavement 5,700 61 >75% Grass cover, Good, HSG B 31,000 91 Weighted Average 5,700 18.39% Pervious Area 25,300 81.61% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1A: Drainage to low point Runoff = 0.86 cfs @ 12.14 hrs, Volume= 2,679 cf, Depth= 1.31" Routed to Pond YD : yard drain at low point Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 2,870 98 Roof patio 21,600 61 >75% Grass cover, Good, HSG B * 40 98 shed 24,510 65 Weighted Average 21,600 88.13% Pervious Area 2,910 11.87% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.6 200 0.0408 0.50 Lag/CN Method, Contour Length= 1,000' Interval= 1' NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 12HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P1B: rear of lot house roofs Runoff = 1.03 cfs @ 12.15 hrs, Volume= 3,256 cf, Depth= 1.87" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 6,800 98 Roofs 700 55 Woods, Good, HSG B 13,310 61 >75% Grass cover, Good, HSG B * 50 98 shed 20,860 73 Weighted Average 14,010 67.16% Pervious Area 6,850 32.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 500 0.0815 1.06 Lag/CN Method, Contour Length= 1,700' Interval= 1' Summary for Subcatchment P1C: Driveway and contributing Runoff = 1.85 cfs @ 12.13 hrs, Volume= 5,563 cf, Depth= 2.88" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 14,280 98 impervious dw, walk, patio 8,085 61 >75% Grass cover, Good, HSG B * 800 98 future impervious 23,165 85 Weighted Average 8,085 34.90% Pervious Area 15,080 65.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1D: Laurel St frontage homes Runoff = 0.26 cfs @ 12.13 hrs, Volume= 891 cf, Depth= 4.23" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 13HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description * 2,525 98 Roofs 2,525 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1E: East Site improvements Runoff = 0.62 cfs @ 12.13 hrs, Volume= 1,830 cf, Depth= 2.27" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 2,160 98 Roofs & Sidewalks 5,120 61 >75% Grass cover, Good, HSG B * 1,200 98 water * 1,200 98 playground 9,680 78 Weighted Average 5,120 52.89% Pervious Area 4,560 47.11% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1F: Overland to Laurel St Runoff = 0.51 cfs @ 12.14 hrs, Volume= 1,547 cf, Depth= 1.44" Routed to Reach CPP1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 10,764 61 >75% Grass cover, Good, HSG B * 2,090 98 impervious 12,854 67 Weighted Average 10,764 83.74% Pervious Area 2,090 16.26% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 14HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P2: To Southern Abutter Runoff = 0.04 cfs @ 12.14 hrs, Volume= 142 cf, Depth= 1.06" Routed to Link SP-P : Total DA P Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,600 61 >75% Grass cover, Good, HSG B 1,600 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach CPE1: Laurel St Drainage System Inflow Area = 93,416 sf, 1.96% Impervious, Inflow Depth = 0.90" for 10-Year event Inflow = 1.45 cfs @ 12.25 hrs, Volume= 7,002 cf Outflow = 1.45 cfs @ 12.25 hrs, Volume= 7,002 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP - E : Total DA Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Reach CPP1: Laurel St Drainage System Inflow Area = 93,594 sf, 36.34% Impervious, Inflow Depth = 0.88" for 10-Year event Inflow = 1.15 cfs @ 12.22 hrs, Volume= 6,897 cf Outflow = 1.15 cfs @ 12.22 hrs, Volume= 6,897 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-P : Total DA P Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Pond BAS: Infiltration Basin Inflow Area = 55,050 sf, 26.01% Impervious, Inflow Depth = 1.69" for 10-Year event Inflow = 2.48 cfs @ 12.15 hrs, Volume= 7,765 cf Outflow = 0.81 cfs @ 12.37 hrs, Volume= 7,765 cf, Atten= 67%, Lag= 13.5 min Discarded = 0.10 cfs @ 12.37 hrs, Volume= 3,864 cf Primary = 0.71 cfs @ 12.37 hrs, Volume= 3,900 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 186.31' @ 12.37 hrs Surf.Area= 1,923 sf Storage= 2,069 cf Plug-Flow detention time= 91.1 min calculated for 7,765 cf (100% of inflow) Center-of-Mass det. time= 91.0 min ( 954.4 - 863.4 ) NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 15HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 185.00' 4,844 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) 185.00 1,251 177.0 0 0 1,251 186.00 1,748 210.0 1,493 1,493 2,286 187.00 2,335 194.0 2,034 3,527 2,838 187.50 2,944 212.0 1,317 4,844 3,429 Device Routing Invert Outlet Devices #1 Primary 185.50'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 186.60'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 185.00'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 183.00' Phase-In= 0.01' #4 Primary 187.25'5.0' long + 3.0 '/' SideZ x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.10 cfs @ 12.37 hrs HW=186.31' (Free Discharge) 3=Exfiltration ( Controls 0.10 cfs) Primary OutFlow Max=0.71 cfs @ 12.37 hrs HW=186.31' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.71 cfs @ 3.61 fps) 2=Orifice/Grate ( Controls 0.00 cfs) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond CUL: cultec Inflow Area = 25,690 sf, 68.53% Impervious, Inflow Depth = 3.01" for 10-Year event Inflow = 2.10 cfs @ 12.13 hrs, Volume= 6,454 cf Outflow = 0.40 cfs @ 12.52 hrs, Volume= 6,454 cf, Atten= 81%, Lag= 23.3 min Discarded = 0.16 cfs @ 12.52 hrs, Volume= 5,004 cf Primary = 0.24 cfs @ 12.52 hrs, Volume= 1,450 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 184.61' @ 12.52 hrs Surf.Area= 3,017 sf Storage= 2,069 cf Plug-Flow detention time= 65.9 min calculated for 6,443 cf (100% of inflow) Center-of-Mass det. time= 65.8 min ( 876.4 - 810.5 ) Volume Invert Avail.Storage Storage Description #1B 183.50' 2,146 cf 40.50'W x 74.50'L x 2.54'H Field B 7,669 cf Overall - 2,305 cf Embedded = 5,364 cf x 40.0% Voids #2B 184.00' 2,305 cf Cultec R-150XLHD x 84 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 12 rows 4,450 cf Total Available Storage NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 16HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Storage Group B created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 184.10'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 185.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 183.50'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 181.20' Phase-In= 0.01' Discarded OutFlow Max=0.16 cfs @ 12.52 hrs HW=184.61' (Free Discharge) 3=Exfiltration ( Controls 0.16 cfs) Primary OutFlow Max=0.24 cfs @ 12.52 hrs HW=184.61' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.24 cfs @ 2.81 fps) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond YD: yard drain at low point Inflow Area = 24,510 sf, 11.87% Impervious, Inflow Depth = 1.31" for 10-Year event Inflow = 0.86 cfs @ 12.14 hrs, Volume= 2,679 cf Outflow = 0.84 cfs @ 12.15 hrs, Volume= 2,679 cf, Atten= 2%, Lag= 0.6 min Primary = 0.84 cfs @ 12.15 hrs, Volume= 2,679 cf Routed to Pond BAS : Infiltration Basin Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 191.69' @ 12.15 hrs Surf.Area= 239 sf Storage= 31 cf Plug-Flow detention time= 0.9 min calculated for 2,675 cf (100% of inflow) Center-of-Mass det. time= 0.9 min ( 883.2 - 882.2 ) Volume Invert Avail.Storage Storage Description #1 191.50' 855 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) 191.50 99 35.0 0 0 99 192.00 600 135.0 157 157 1,452 193.00 800 150.0 698 855 1,821 Device Routing Invert Outlet Devices #1 Primary 191.50'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.83 cfs @ 12.15 hrs HW=191.69' (Free Discharge) 1=Orifice/Grate (Weir Controls 0.83 cfs @ 1.42 fps) NRCC 24-hr C 10-Year Rainfall=4.47"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 17HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Link SP - E: Total DA Inflow Area = 95,194 sf, 1.92% Impervious, Inflow Depth = 0.90" for 10-Year event Inflow = 1.48 cfs @ 12.25 hrs, Volume= 7,151 cf Primary = 1.48 cfs @ 12.25 hrs, Volume= 7,151 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-LS: Laurel Street catch basins Inflow Area = 126,194 sf, 47.00% Impervious, Inflow Depth = 1.52" for 10-Year event Inflow = 3.93 cfs @ 12.14 hrs, Volume= 16,000 cf Primary = 3.93 cfs @ 12.14 hrs, Volume= 16,000 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-P: Total DA P Inflow Area = 95,194 sf, 35.73% Impervious, Inflow Depth = 0.89" for 10-Year event Inflow = 1.18 cfs @ 12.21 hrs, Volume= 7,038 cf Primary = 1.18 cfs @ 12.21 hrs, Volume= 7,038 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-LS : Laurel Street catch basins Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 18HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment E1A: Laurel St direct sheet flow Runoff = 0.19 cfs @ 12.14 hrs, Volume= 585 cf, Depth= 1.78" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description 1,040 61 >75% Grass cover, Good, HSG B 2,429 55 Woods, Good, HSG B * 400 96 gravel * 71 98 impervious 3,940 62 Weighted Average 3,869 98.20% Pervious Area 71 1.80% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment E1B: To Laurel St bottom of site Runoff = 2.57 cfs @ 12.24 hrs, Volume= 11,015 cf, Depth= 1.48" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 1,761 98 Roofs & Pavement 34,287 61 >75% Grass cover, Good, HSG B * 42 96 Gravel surface 53,386 55 Woods, Good, HSG B 89,476 58 Weighted Average 87,715 98.03% Pervious Area 1,761 1.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.2 520 0.0586 0.61 Lag/CN Method, Contour Length= 5,240' Interval= 1' Summary for Subcatchment E2: To Southern Abutter Runoff = 0.08 cfs @ 12.14 hrs, Volume= 241 cf, Depth= 1.63" Routed to Link SP - E : Total DA Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 19HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description 1,614 61 >75% Grass cover, Good, HSG B 164 55 Woods, Good, HSG B 1,778 60 Weighted Average 1,778 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment LS: To Laurel St Drainage System Runoff = 3.65 cfs @ 12.13 hrs, Volume= 11,645 cf, Depth= 4.51" Routed to Link SP-LS : Laurel Street catch basins Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 25,300 98 Roofs & Pavement 5,700 61 >75% Grass cover, Good, HSG B 31,000 91 Weighted Average 5,700 18.39% Pervious Area 25,300 81.61% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1A: Drainage to low point Runoff = 1.36 cfs @ 12.14 hrs, Volume= 4,131 cf, Depth= 2.02" Routed to Pond YD : yard drain at low point Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 2,870 98 Roof patio 21,600 61 >75% Grass cover, Good, HSG B * 40 98 shed 24,510 65 Weighted Average 21,600 88.13% Pervious Area 2,910 11.87% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.6 200 0.0408 0.50 Lag/CN Method, Contour Length= 1,000' Interval= 1' NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 20HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P1B: rear of lot house roofs Runoff = 1.50 cfs @ 12.15 hrs, Volume= 4,713 cf, Depth= 2.71" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 6,800 98 Roofs 700 55 Woods, Good, HSG B 13,310 61 >75% Grass cover, Good, HSG B * 50 98 shed 20,860 73 Weighted Average 14,010 67.16% Pervious Area 6,850 32.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 500 0.0815 1.06 Lag/CN Method, Contour Length= 1,700' Interval= 1' Summary for Subcatchment P1C: Driveway and contributing Runoff = 2.45 cfs @ 12.13 hrs, Volume= 7,471 cf, Depth= 3.87" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 14,280 98 impervious dw, walk, patio 8,085 61 >75% Grass cover, Good, HSG B * 800 98 future impervious 23,165 85 Weighted Average 8,085 34.90% Pervious Area 15,080 65.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1D: Laurel St frontage homes Runoff = 0.32 cfs @ 12.13 hrs, Volume= 1,116 cf, Depth= 5.30" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 21HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description * 2,525 98 Roofs 2,525 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1E: East Site improvements Runoff = 0.86 cfs @ 12.13 hrs, Volume= 2,562 cf, Depth= 3.18" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description * 2,160 98 Roofs & Sidewalks 5,120 61 >75% Grass cover, Good, HSG B * 1,200 98 water * 1,200 98 playground 9,680 78 Weighted Average 5,120 52.89% Pervious Area 4,560 47.11% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1F: Overland to Laurel St Runoff = 0.79 cfs @ 12.13 hrs, Volume= 2,344 cf, Depth= 2.19" Routed to Reach CPP1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description 10,764 61 >75% Grass cover, Good, HSG B * 2,090 98 impervious 12,854 67 Weighted Average 10,764 83.74% Pervious Area 2,090 16.26% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 22HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P2: To Southern Abutter Runoff = 0.07 cfs @ 12.14 hrs, Volume= 227 cf, Depth= 1.70" Routed to Link SP-P : Total DA P Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 25-Year Rainfall=5.54" Area (sf) CN Description 1,600 61 >75% Grass cover, Good, HSG B 1,600 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach CPE1: Laurel St Drainage System Inflow Area = 93,416 sf, 1.96% Impervious, Inflow Depth = 1.49" for 25-Year event Inflow = 2.67 cfs @ 12.24 hrs, Volume= 11,600 cf Outflow = 2.67 cfs @ 12.24 hrs, Volume= 11,600 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP - E : Total DA Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Reach CPP1: Laurel St Drainage System Inflow Area = 93,594 sf, 36.34% Impervious, Inflow Depth = 1.54" for 25-Year event Inflow = 2.25 cfs @ 12.27 hrs, Volume= 12,005 cf Outflow = 2.25 cfs @ 12.27 hrs, Volume= 12,005 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-P : Total DA P Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Pond BAS: Infiltration Basin Inflow Area = 55,050 sf, 26.01% Impervious, Inflow Depth = 2.49" for 25-Year event Inflow = 3.68 cfs @ 12.15 hrs, Volume= 11,406 cf Outflow = 1.70 cfs @ 12.29 hrs, Volume= 11,406 cf, Atten= 54%, Lag= 8.8 min Discarded = 0.12 cfs @ 12.29 hrs, Volume= 4,376 cf Primary = 1.58 cfs @ 12.29 hrs, Volume= 7,030 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 186.76' @ 12.29 hrs Surf.Area= 2,183 sf Storage= 2,974 cf Plug-Flow detention time= 76.5 min calculated for 11,406 cf (100% of inflow) Center-of-Mass det. time= 76.4 min ( 927.8 - 851.4 ) NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 23HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 185.00' 4,844 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) 185.00 1,251 177.0 0 0 1,251 186.00 1,748 210.0 1,493 1,493 2,286 187.00 2,335 194.0 2,034 3,527 2,838 187.50 2,944 212.0 1,317 4,844 3,429 Device Routing Invert Outlet Devices #1 Primary 185.50'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 186.60'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 185.00'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 183.00' Phase-In= 0.01' #4 Primary 187.25'5.0' long + 3.0 '/' SideZ x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.12 cfs @ 12.29 hrs HW=186.75' (Free Discharge) 3=Exfiltration ( Controls 0.12 cfs) Primary OutFlow Max=1.56 cfs @ 12.29 hrs HW=186.75' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.95 cfs @ 4.82 fps) 2=Orifice/Grate (Weir Controls 0.62 cfs @ 1.28 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond CUL: cultec Inflow Area = 25,690 sf, 68.53% Impervious, Inflow Depth = 4.01" for 25-Year event Inflow = 2.77 cfs @ 12.13 hrs, Volume= 8,587 cf Outflow = 0.52 cfs @ 12.51 hrs, Volume= 8,587 cf, Atten= 81%, Lag= 22.8 min Discarded = 0.17 cfs @ 12.51 hrs, Volume= 5,957 cf Primary = 0.35 cfs @ 12.51 hrs, Volume= 2,630 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 184.97' @ 12.51 hrs Surf.Area= 3,017 sf Storage= 2,870 cf Plug-Flow detention time= 70.2 min calculated for 8,573 cf (100% of inflow) Center-of-Mass det. time= 70.1 min ( 872.6 - 802.5 ) Volume Invert Avail.Storage Storage Description #1B 183.50' 2,146 cf 40.50'W x 74.50'L x 2.54'H Field B 7,669 cf Overall - 2,305 cf Embedded = 5,364 cf x 40.0% Voids #2B 184.00' 2,305 cf Cultec R-150XLHD x 84 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 12 rows 4,450 cf Total Available Storage NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 24HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Storage Group B created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 184.10'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 185.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 183.50'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 181.20' Phase-In= 0.01' Discarded OutFlow Max=0.17 cfs @ 12.51 hrs HW=184.96' (Free Discharge) 3=Exfiltration ( Controls 0.17 cfs) Primary OutFlow Max=0.35 cfs @ 12.51 hrs HW=184.96' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.35 cfs @ 4.02 fps) 2=Orifice/Grate ( Controls 0.00 cfs) Summary for Pond YD: yard drain at low point Inflow Area = 24,510 sf, 11.87% Impervious, Inflow Depth = 2.02" for 25-Year event Inflow = 1.36 cfs @ 12.14 hrs, Volume= 4,131 cf Outflow = 1.34 cfs @ 12.15 hrs, Volume= 4,131 cf, Atten= 2%, Lag= 0.6 min Primary = 1.34 cfs @ 12.15 hrs, Volume= 4,131 cf Routed to Pond BAS : Infiltration Basin Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 191.76' @ 12.15 hrs Surf.Area= 304 sf Storage= 49 cf Plug-Flow detention time= 0.8 min calculated for 4,125 cf (100% of inflow) Center-of-Mass det. time= 0.8 min ( 868.4 - 867.5 ) Volume Invert Avail.Storage Storage Description #1 191.50' 855 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) 191.50 99 35.0 0 0 99 192.00 600 135.0 157 157 1,452 193.00 800 150.0 698 855 1,821 Device Routing Invert Outlet Devices #1 Primary 191.50'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.33 cfs @ 12.15 hrs HW=191.76' (Free Discharge) 1=Orifice/Grate (Weir Controls 1.33 cfs @ 1.65 fps) NRCC 24-hr C 25-Year Rainfall=5.54"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 25HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Link SP - E: Total DA Inflow Area = 95,194 sf, 1.92% Impervious, Inflow Depth = 1.49" for 25-Year event Inflow = 2.71 cfs @ 12.23 hrs, Volume= 11,841 cf Primary = 2.71 cfs @ 12.23 hrs, Volume= 11,841 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-LS: Laurel Street catch basins Inflow Area = 126,194 sf, 47.00% Impervious, Inflow Depth = 2.27" for 25-Year event Inflow = 5.48 cfs @ 12.14 hrs, Volume= 23,877 cf Primary = 5.48 cfs @ 12.14 hrs, Volume= 23,877 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-P: Total DA P Inflow Area = 95,194 sf, 35.73% Impervious, Inflow Depth = 1.54" for 25-Year event Inflow = 2.28 cfs @ 12.27 hrs, Volume= 12,232 cf Primary = 2.28 cfs @ 12.27 hrs, Volume= 12,232 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-LS : Laurel Street catch basins Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 26HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment E1A: Laurel St direct sheet flow Runoff = 0.37 cfs @ 12.13 hrs, Volume= 1,087 cf, Depth= 3.31" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,040 61 >75% Grass cover, Good, HSG B 2,429 55 Woods, Good, HSG B * 400 96 gravel * 71 98 impervious 3,940 62 Weighted Average 3,869 98.20% Pervious Area 71 1.80% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment E1B: To Laurel St bottom of site Runoff = 5.35 cfs @ 12.23 hrs, Volume= 21,492 cf, Depth= 2.88" Routed to Reach CPE1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 1,761 98 Roofs & Pavement 34,287 61 >75% Grass cover, Good, HSG B * 42 96 Gravel surface 53,386 55 Woods, Good, HSG B 89,476 58 Weighted Average 87,715 98.03% Pervious Area 1,761 1.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.2 520 0.0586 0.61 Lag/CN Method, Contour Length= 5,240' Interval= 1' Summary for Subcatchment E2: To Southern Abutter Runoff = 0.15 cfs @ 12.13 hrs, Volume= 459 cf, Depth= 3.10" Routed to Link SP - E : Total DA Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 27HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description 1,614 61 >75% Grass cover, Good, HSG B 164 55 Woods, Good, HSG B 1,778 60 Weighted Average 1,778 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment LS: To Laurel St Drainage System Runoff = 5.22 cfs @ 12.13 hrs, Volume= 17,072 cf, Depth= 6.61" Routed to Link SP-LS : Laurel Street catch basins Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 25,300 98 Roofs & Pavement 5,700 61 >75% Grass cover, Good, HSG B 31,000 91 Weighted Average 5,700 18.39% Pervious Area 25,300 81.61% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1A: Drainage to low point Runoff = 2.48 cfs @ 12.14 hrs, Volume= 7,429 cf, Depth= 3.64" Routed to Pond YD : yard drain at low point Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 2,870 98 Roof patio 21,600 61 >75% Grass cover, Good, HSG B * 40 98 shed 24,510 65 Weighted Average 21,600 88.13% Pervious Area 2,910 11.87% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.6 200 0.0408 0.50 Lag/CN Method, Contour Length= 1,000' Interval= 1' NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 28HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P1B: rear of lot house roofs Runoff = 2.49 cfs @ 12.15 hrs, Volume= 7,870 cf, Depth= 4.53" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 6,800 98 Roofs 700 55 Woods, Good, HSG B 13,310 61 >75% Grass cover, Good, HSG B * 50 98 shed 20,860 73 Weighted Average 14,010 67.16% Pervious Area 6,850 32.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 500 0.0815 1.06 Lag/CN Method, Contour Length= 1,700' Interval= 1' Summary for Subcatchment P1C: Driveway and contributing Runoff = 3.64 cfs @ 12.13 hrs, Volume= 11,399 cf, Depth= 5.90" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 14,280 98 impervious dw, walk, patio 8,085 61 >75% Grass cover, Good, HSG B * 800 98 future impervious 23,165 85 Weighted Average 8,085 34.90% Pervious Area 15,080 65.10% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1D: Laurel St frontage homes Runoff = 0.44 cfs @ 12.13 hrs, Volume= 1,566 cf, Depth= 7.44" Routed to Pond CUL : cultec Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 29HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Area (sf) CN Description * 2,525 98 Roofs 2,525 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1E: East Site improvements Runoff = 1.36 cfs @ 12.13 hrs, Volume= 4,111 cf, Depth= 5.10" Routed to Pond BAS : Infiltration Basin Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 2,160 98 Roofs & Sidewalks 5,120 61 >75% Grass cover, Good, HSG B * 1,200 98 water * 1,200 98 playground 9,680 78 Weighted Average 5,120 52.89% Pervious Area 4,560 47.11% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P1F: Overland to Laurel St Runoff = 1.40 cfs @ 12.13 hrs, Volume= 4,132 cf, Depth= 3.86" Routed to Reach CPP1 : Laurel St Drainage System Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 10,764 61 >75% Grass cover, Good, HSG B * 2,090 98 impervious 12,854 67 Weighted Average 10,764 83.74% Pervious Area 2,090 16.26% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 30HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Subcatchment P2: To Southern Abutter Runoff = 0.14 cfs @ 12.13 hrs, Volume= 427 cf, Depth= 3.20" Routed to Link SP-P : Total DA P Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,600 61 >75% Grass cover, Good, HSG B 1,600 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Reach CPE1: Laurel St Drainage System Inflow Area = 93,416 sf, 1.96% Impervious, Inflow Depth = 2.90" for 100-Year event Inflow = 5.55 cfs @ 12.23 hrs, Volume= 22,579 cf Outflow = 5.55 cfs @ 12.23 hrs, Volume= 22,579 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP - E : Total DA Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Reach CPP1: Laurel St Drainage System Inflow Area = 93,594 sf, 36.34% Impervious, Inflow Depth = 3.06" for 100-Year event Inflow = 5.45 cfs @ 12.25 hrs, Volume= 23,849 cf Outflow = 5.45 cfs @ 12.25 hrs, Volume= 23,849 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-P : Total DA P Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Pond BAS: Infiltration Basin Inflow Area = 55,050 sf, 26.01% Impervious, Inflow Depth = 4.23" for 100-Year event Inflow = 6.19 cfs @ 12.15 hrs, Volume= 19,410 cf Outflow = 4.20 cfs @ 12.23 hrs, Volume= 19,410 cf, Atten= 32%, Lag= 4.9 min Discarded = 0.15 cfs @ 12.23 hrs, Volume= 5,024 cf Primary = 4.05 cfs @ 12.23 hrs, Volume= 14,385 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 187.19' @ 12.23 hrs Surf.Area= 2,561 sf Storage= 3,998 cf Plug-Flow detention time= 55.6 min calculated for 19,378 cf (100% of inflow) Center-of-Mass det. time= 55.9 min ( 890.9 - 834.9 ) NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 31HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Volume Invert Avail.Storage Storage Description #1 185.00' 4,844 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) 185.00 1,251 177.0 0 0 1,251 186.00 1,748 210.0 1,493 1,493 2,286 187.00 2,335 194.0 2,034 3,527 2,838 187.50 2,944 212.0 1,317 4,844 3,429 Device Routing Invert Outlet Devices #1 Primary 185.50'6.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 186.60'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 185.00'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 183.00' Phase-In= 0.01' #4 Primary 187.25'5.0' long + 3.0 '/' SideZ x 10.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.49 2.56 2.70 2.69 2.68 2.69 2.67 2.64 Discarded OutFlow Max=0.15 cfs @ 12.23 hrs HW=187.18' (Free Discharge) 3=Exfiltration ( Controls 0.15 cfs) Primary OutFlow Max=4.02 cfs @ 12.23 hrs HW=187.18' (Free Discharge) 1=Orifice/Grate (Orifice Controls 1.13 cfs @ 5.76 fps) 2=Orifice/Grate (Orifice Controls 2.89 cfs @ 3.67 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond CUL: cultec Inflow Area = 25,690 sf, 68.53% Impervious, Inflow Depth = 6.06" for 100-Year event Inflow = 4.09 cfs @ 12.13 hrs, Volume= 12,964 cf Outflow = 1.29 cfs @ 12.32 hrs, Volume= 12,964 cf, Atten= 68%, Lag= 11.7 min Discarded = 0.22 cfs @ 12.32 hrs, Volume= 7,633 cf Primary = 1.07 cfs @ 12.32 hrs, Volume= 5,332 cf Routed to Reach CPP1 : Laurel St Drainage System Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 185.93' @ 12.32 hrs Surf.Area= 3,017 sf Storage= 4,318 cf Plug-Flow detention time= 74.7 min calculated for 12,943 cf (100% of inflow) Center-of-Mass det. time= 74.6 min ( 865.6 - 791.0 ) Volume Invert Avail.Storage Storage Description #1B 183.50' 2,146 cf 40.50'W x 74.50'L x 2.54'H Field B 7,669 cf Overall - 2,305 cf Embedded = 5,364 cf x 40.0% Voids #2B 184.00' 2,305 cf Cultec R-150XLHD x 84 Inside #1 Effective Size= 29.8"W x 18.0"H => 2.65 sf x 10.25'L = 27.2 cf Overall Size= 33.0"W x 18.5"H x 11.00'L with 0.75' Overlap Row Length Adjustment= +0.75' x 2.65 sf x 12 rows 4,450 cf Total Available Storage NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 32HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Storage Group B created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 184.10'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 185.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 183.50'1.500 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 181.20' Phase-In= 0.01' Discarded OutFlow Max=0.22 cfs @ 12.32 hrs HW=185.92' (Free Discharge) 3=Exfiltration ( Controls 0.22 cfs) Primary OutFlow Max=1.04 cfs @ 12.32 hrs HW=185.92' (Free Discharge) 1=Orifice/Grate (Orifice Controls 0.54 cfs @ 6.20 fps) 2=Orifice/Grate (Weir Controls 0.50 cfs @ 1.36 fps) Summary for Pond YD: yard drain at low point Inflow Area = 24,510 sf, 11.87% Impervious, Inflow Depth = 3.64" for 100-Year event Inflow = 2.48 cfs @ 12.14 hrs, Volume= 7,429 cf Outflow = 2.38 cfs @ 12.15 hrs, Volume= 7,429 cf, Atten= 4%, Lag= 0.9 min Primary = 2.38 cfs @ 12.15 hrs, Volume= 7,429 cf Routed to Pond BAS : Infiltration Basin Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Peak Elev= 191.89' @ 12.15 hrs Surf.Area= 459 sf Storage= 101 cf Plug-Flow detention time= 0.8 min calculated for 7,416 cf (100% of inflow) Center-of-Mass det. time= 0.8 min ( 849.3 - 848.5 ) Volume Invert Avail.Storage Storage Description #1 191.50' 855 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) 191.50 99 35.0 0 0 99 192.00 600 135.0 157 157 1,452 193.00 800 150.0 698 855 1,821 Device Routing Invert Outlet Devices #1 Primary 191.50'12.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=2.36 cfs @ 12.15 hrs HW=191.89' (Free Discharge) 1=Orifice/Grate (Orifice Controls 2.36 cfs @ 3.01 fps) NRCC 24-hr C 100-Year Rainfall=7.68"23 Laurel Street FINAL rev Printed 7/13/2022Prepared by Berkshire Design Group Page 33HydroCAD® 10.10-7b s/n 10759 © 2022 HydroCAD Software Solutions LLC Summary for Link SP - E: Total DA Inflow Area = 95,194 sf, 1.92% Impervious, Inflow Depth = 2.90" for 100-Year event Inflow = 5.65 cfs @ 12.22 hrs, Volume= 23,037 cf Primary = 5.65 cfs @ 12.22 hrs, Volume= 23,037 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-LS: Laurel Street catch basins Inflow Area = 126,194 sf, 47.00% Impervious, Inflow Depth = 3.93" for 100-Year event Inflow = 10.61 cfs @ 12.15 hrs, Volume= 41,348 cf Primary = 10.61 cfs @ 12.15 hrs, Volume= 41,348 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Summary for Link SP-P: Total DA P Inflow Area = 95,194 sf, 35.73% Impervious, Inflow Depth = 3.06" for 100-Year event Inflow = 5.57 cfs @ 12.15 hrs, Volume= 24,276 cf Primary = 5.57 cfs @ 12.15 hrs, Volume= 24,276 cf, Atten= 0%, Lag= 0.0 min Routed to Link SP-LS : Laurel Street catch basins Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Appendix D – Groundwater Recharge Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group June 24, 2022 Northampton – 23 Laurel Street Stormwater Standard 3 – Recharge Calculations Impervious Area of proposed project Table 1 shows the existing and proposed impervious areas. Table 1. Existing and Proposed Impervious Area Existing Area (sf) Proposed Area (sf) Impervious 2,203 32,725 Proposed New Impervious Area & Required Recharge Volume Table 2 shows the required recharge volume. Required Recharge Volume is calculated by applying the following equation: Required Recharge Volume, = × Where, = Target Depth Factor, 0.35” (for HSG B) = Impervious Area Table 2. Proposed Increase in Impervious Area and Required Recharge Volume Impervious area (sq. ft.) Required Recharge Volume (cu. ft.) Provided Recharge Volume (cu. ft.) 32,725 955 1,540 The storage volume provided in Table 2 is provided by ponding below the outlet of each stormwater facility. For the open infiltration area, the storage volume was calculated by average end area applied to contours, as shown on the Grading Plan. For the subsurface system, the volume was calculated through the chamber wizard within the HydroCAD program. This analysis utilizes the “Static Method” for determining required storage volume for infiltration features. Therefore, the minimum required storage volume is equal to the Required Recharge Volume, tabulated above. The provided infiltration storage volume of 1,540 cu. ft. exceeds the required recharge volume of 955 cu. ft. (considering all new impervious surfaces at the future site). June 24, 2022 Northampton – 23 Laurel Street Stormwater Standard 3 – Recharge Calculations Page 2 of 2 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com 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 23 Laurel Street site, portions of the driveway and patios and walkways fronting Laurel Street cannot be captured by the on-site stormwater facilities. 1. Required recharge volume (static): 955 cu. ft. (all impervious surfaces) 2. Impervious area draining to recharge facilities: 30,635 sq. ft. 3. Total impervious/impervious draining to facilities: 32725/30,635= 1.07 4. 1.07*955 = 1,020 cu. ft. Provided recharge of 1,540 cu. ft. > 1,020 cu. ft. The provided recharge exceeds the required recharge with the capture area adjustment. Drawdown Time The Rawls infiltration rate for the underlying soils found at the site is used to calculate the drainage time for the recharge facilities. At 23 Laurel Street an infiltration rate of 3”/hr was measured in on-site test pits. For these calculations one half that rate or 1.5 “/hr is used. The open basin will pond approximately 6” (the depth below the lowest outlet. 6 1.5 /ℎ = 4 ℎ Drawdown for the open infiltration basin is estimated at 4 hours. The subsurface system will allow approximately 7.2” of ponding. Drawdown for that system is estimated at 5 hours. 7.2 1.5 /ℎ = 4.8 ℎ 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Appendix E – Water Quality Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group June 24, 2022 23 Laurel Street, Northampton, MA Stormwater Standard 4 – Water Quality Volume Existing conditions include impervious areas of 2,203 sf within the project site. Proposed conditions include 32,965 sf of impervious area. The increase in impervious area is 30,725 sq. ft. (Table 1). Table 1. Existing and Proposed Impervious Areas Existing Area (sf) Proposed Area (sf) Increase in Area (sf) Impervious 2,203 32,725 30,522 Required Water Quality Volume is calculated by applying the following equation: Required Water Quality Volume, = × Where, = Depth Factor, .5”; = Impervious Area Infiltration capacity for the site is the total volume stored below the outlets of the systems. For the open basin the volume was calculated by average end area applied to contours, as shown on the Grading and Drainage Plan. Table 2. Required and Provided WQv Impervious Area (sf) Water Quality Volume (cf) Water Quality Volume Provided (cf) 32,725 1,364 1,540 The water quality volume provided exceeds the water quality volume required on the increase in impervious area (Table 2). Water Quality Volume by drainage area Table 3. Proposed Impervious Areas and Water Quality Volume Location (See Figure 3) Proposed Impervious Area (Ia) (sf) Stormwater Facility WQV Required/provided P1A, P1B, P1E 13,030 Infiltration basin 543 cf / 688 cf P1C, P1D 17,605 Subsurface infiltration 734 cf / 852 cf June 24, 2022 Northampton – 23 Laurel Street Stormwater Standard 4 – Water Quality Volume Page 2 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com P2 2,090 Not captured – flows to Laurel Street 87 cf / 0 cf TSS Removal: The design for the site provides TSS removal with a Stormceptor water quality unit (driveway, parking, walkways and some patios) and infiltration. The majority of the driveway, parking, and walkway surfaces (91%) is directed to a Stormceptor water quality unit rated by the manufacturer at 85% TSS removal. The runoff from the stormceptor is directed to subsurface infiltration which provides 80% removal. The remaining impervious surfaces comprised of roofs, patios, and playground are directed to an infiltration basin providing 80% TSS removal. Overall, 94% of the site impervious area is infiltrated in two facilities. 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:Northampton - 23 LaurelPrepared By:Berkshire Design Grp*Equals remaining load from previous BMP (E)Date:6/24/2022which enters the BMPDA P1A/B/ETSS 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)Subsurface Infiltration Structure 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:Northampton - 23 LaurelPrepared By:Berkshire Design Grp*Equals remaining load from previous BMP (E)Date:6/24/2022which enters the BMPDA P1DTSS Removal Calculation WorksheetNon-automated TSS Calculation Sheetmust be used if Proprietary BMP Proposed1. From MassDEP Stormwater Handbook Vol. 1Mass. Dept. of Environmental Protection INSTRUCTIONS:Non-automated: Mar. 4, 20081. Sheet is nonautomated. Print sheet and complete using hand calculations. Column A and B: See MassDEP Structural BMP Table2. The calculations must be completed using the Column Headings specified in Chart and Not the Excel Column Headings3. To complete Chart Column D, multiple Column B value within Row x Column C value within Row4. To complete Chart Column E value, subtract Column D value within Row from Column C within Row5. Total TSS Removal = Sum All Values in Column DLocation: A B C D ETSS Removal Starting TSS Amount RemainingBMP1Rate1Load* Removed (B*C) Load (C-D)1.00Total TSS Removal =Separate Form Needs to be Completed for Each Outlet or BMP TrainProject:Prepared By:*Equals remaining load from previous BMP (E)Date:which enters the BMPTSS Removal Calculation WorksheetNon-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed1. From MassDEP Stormwater Handbook Vol. 1Mass. Dept. of Environmental Protection Project Information & Location Project Name 23 Laurel Street Project Number 49569 City State/ Province Massachusetts Country United States of America Date 6/16/2022 Designer Information EOR Information (optional) Name Lucy Conley Name Company Berkshire Design Group Company Phone #413-582-7000 Phone # Email lucy@berkshiredesign.com Email Brief Stormceptor Sizing Report - 23 Laurel Street Site Name Target TSS Removal (%)80 TSS Removal (%) Provided 85 Recommended Stormceptor Model STC 450i Stormceptor Sizing Summary Stormceptor Model % TSS Removal Provided STC 450i 85 STC 900 91 STC 1200 91 STC 1800 91 STC 2400 93 STC 3600 94 STC 4800 95 STC 6000 96 STC 7200 97 STC 11000 98 STC 13000 98 STC 16000 98 The recommended Stormceptor Model achieves the water quality objectives based on the selected inputs, historical rainfall records and selected particle size distribution. Stormwater Treatment Recommendation The recommended Stormceptor Model(s) which achieve or exceed the user defined water quality objective for each site within the project are listed in the below Sizing Summary table. Stormceptor Brief Sizing Report ±Page 1 of 2 Notes ‡Stormceptor performance estimates are based on simulations using PCSWMM for Stormceptor, which uses the EPA Rainfall and Runoff modules. ‡Design estimates listed are only representative of specific project requirements based on total suspended solids (TSS) removal defined by the selected PSD, and based on stable site conditions only, after construction is completed. ‡For submerged applications or sites specific to spill control, please contact your local Stormceptor representative for further design assistance. Drainage Area Total Area (acres)0.53 Imperviousness %65.1 Water Quality Objective TSS Removal (%)80.0 Runoff Volume Capture (%) Oil Spill Capture Volume (Gal) Peak Conveyed Flow Rate (CFS) Water Quality Flow Rate (CFS) Rainfall Station Name KNIGHTVILLE DAM State/Province Massachusetts Station ID #3985 Years of Records 14 Latitude 42°10'12"N Longitude 72°31'12"W Up Stream Storage Storage (ac-ft)Discharge (cfs) 0.000 0.000 Particle Size Distribution (PSD) The selected PSD defines TSS removal Fine Distribution Particle Diameter (microns) Distribution % Specific Gravity 20.0 20.0 1.30 60.0 20.0 1.80 150.0 20.0 2.20 400.0 20.0 2.65 2000.0 20.0 2.65 Up Stream Flow Diversion Max. Flow to Stormceptor (cfs) Sizing Details For Stormceptor Specifications and Drawings Please Visit: https://www.conteches.com/technical-guides/search?filter=1WBC0O5EYX Stormceptor Brief Sizing Report ±Page 2 of 2 23 Laurel Street Northampton, Massachusetts Stormwater Management Report Berkshire Design Group Appendix F – Stormwater Management System – Operation & Maintenance Plan 23 Laurel Street June 24, 2022 Rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. 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 rainstorms 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 rainstorm 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. 23 Laurel Street June 24, 2022 Rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 2 Post-Construction Stormwater Management System Owner: Valley Community Development Corporation Party Responsible for Operation & Maintenance: Valley Community Development Corporation Inspection & Maintenance Schedule: 1) Yard Drains Yard drains should be inspected quarterly and cleaned annually or more often if required. Oil and sediments should be removed and disposed of in accordance with local, state and federal guidelines and regulations. In the case of an oil or bulk pollutant release, the system must be cleaned immediately following the spill and the proper authorities notified. 2) Catch basins Structures shall be inspected four times per year and cleaned if sediment build up exceeds 6” but no less than every 2 years. Oil and sediments shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. In the case of an oil or bulk pollutant release, the system must be cleaned immediately following the spill and the proper authorities notified. 3) Water Quality Unit The stormwater treatment chamber is a Stormceptor manufactured by Contech. This unit provides water quality for the parking lot expansion. The stormwater treatment chamber should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The system shall be inspected at least four times during the first year and at least twice per year thereafter. Sediment shall be removed any time it has built up to more than 6” deep. If sediment accumulates fast enough to require removal more than once per year, the inspection frequency shall be increased. The visual inspection should ascertain that the system components are in working order and that there are no blockages or obstructions in the inlet and separation screen. The inspection should also quantify the accumulation of hydrocarbons, trash, and sediment in the system. Measuring pollutant accumulation can be done with a calibrated dipstick, tape measure or other measuring instrument. The hydrodynamic separator system should be cleaned when the level of sediment has reached 6 inches or when an appreciable level of hydrocarbons and trash covers over 50% of the water surface of the separator. The level of sediment is easily determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than 23 Laurel Street June 24, 2022 Rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 3 consolidated particles toward the bottom of the pile. Sediment shall be removed by a vacuum truck and disposed of in accordance with applicable regulations. 4) Sediment Forebay The sediment forebay shall be inspected monthly for sediment accumulation and signs of damage or erosion. Sediment shall be removed four times per year with one event after the completion of spring snow melt. Sediment shall be disposed of in accordance with local, state, and federal guidelines and regulations. When mowing grasses, keep the height no greater than 6 inches. Set the mower blades no lower than 4 inches. Check for signs of rilling and gullying and repair as needed. After removing the sediment, replace any vegetation damaged during the clean-out by either reseeding or re-sodding. When reseeding, incorporate practices such as hydroseeding with a tackifier, blanket, or similar practice to ensure that no scour occurs in the forebay, while the seeds germinate and develop roots. 5) Subsurface detention and Infiltration System A. Check all inlets and outlets through inspection ports for clogging and remove any debris quarterly in the first year and at least yearly thereafter. All materials removed from the outlet control structure shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. B. Sediment accumulation: The subsurface detention and infiltration system includes a separator row designed to capture the first flush of a rain event. The Cultec Separator row is a row of chambers surrounded on all sides by filter fabric. This configuration is designed to trap any sediment or debris that may pass through the upstream pretreatment and into the chamber system. As recommended by Cultec, the Separator row shall be inspected every six months for the first year of service and annually thereafter. Inspection of the Separator row is achieved via an inspection port riser installed on one end. When the sediment depth exceeds 3” in the Separator row, the JetVac procedure described in the attached Cultec literature shall be used to remove the sediment from the Separator row. Sediment-laden water can be filtered through a Dirtbag® or approved equivalent if permitted by the locality. All materials removed from the outlet control structure shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. C. If additional sediment is observed in the infiltration basin beyond the Separator row or if ponding is observed within the chamber system more than 72-hours after a storm, the owner should contact a professional engineer to evaluate the impact to the detention basin, recommend changes to the pre-treatment devices or maintenance procedures, and to determine if remedial action is necessary. 6) Infiltration basin The infiltration basin shall be inspected after every major storm for the first three months and two times per year thereafter. Failure of the system to drain (ponding 48 hours after the end of the storm) shall result in inspection and cleaning. Inspections shall identify any damage or signs of erosion within basins or the overflow berm. Damage shall be repaired immediately. At least twice per year, mow the buffer area, side slopes, and basin bottom. Remove grass clippings and 23 Laurel Street June 24, 2022 Rev July 14, 2022 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 4 accumulated organic matter to prevent an impervious organic mat from forming. Remove trash and debris at the same time. Use deep tilling to break up any clogged surfaces and revegetate immediately. Remove sediment from the basin as necessary but wait until the floor is thoroughly dry. Use light equipment to remove the top layer so as to not compact the underlying soil. Deeply till the remaining soil and revegetate as soon as possible. Rake sediment from stone areas and remove. It is recommended that sediment removal be performed after the completion of the spring snow melt. 7) Outlet Control Structure The outlet control structure for the Cultec system shall be inspected quarterly and after large storms (greater than 2” in 24-hours) to ensure no debris is prohibiting flow through the outlet orifices in the riser pipe. Inspections should confirm that there is no standing water in the structure and that the bottom is visible. All materials removed from the outlet control structure shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. 23 Laurel Street Northampton, 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.