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1093 Westhampton Road Stormwater permit 8.17.2022 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group August 17, 2022 Doug McDonald Northampton DPW RE: 1093 Westhampton Road (Lot 1) TJDL Development – Common Drive & 3 Single Family Lots Stormwater Permit Dear Doug: Based on the Engineer’s Certificate of Compliance for the subdivision dated June 10, 2017, we have prepared the following plans for Lot 1 of the TJDL Development. The plan incorporates stormwater improvements to address the following items noted in the Certificate of Compliance:  Exception 2 regarding the grassed swale at the end of the common drive - during construction, the swale was constructed shorter than the design length: As part of Lot 1 construction the swale will be extended south to provide additional detention. In addition, a cutoff swale extends further south to capture additional runoff from Lot 1.  Inspection item 1 regarding the level spreader for the grassed swale outlet: As part of Lot 1 construction, the level spreader shall be re-installed so that it is level. In addition, any depressions down gradient of the spreader shall be filled with compacted crushed rock.  Provision 2 – allotments of clearing (20,000 sf) and impervious area (5,000 sf) for lot 1: The additional clearing and impervious area proposed for Lot 1 is addressed by increasing the storage area within grassed swale. In addition, a portion of the roof is conveyed to a subsurface storage chamber which will store and infiltrate the first inch of runoff.  Not noted – the stormwater swale was modeled with a 4” outlet pipe but a 6” pipe was installed. In order to reduce the flow out, as part of the Lot 1 development, a cap with a 4” orifice will be installed at the inlet of the 6” pipe and fastened with a Fernco. Taking the approved post-development HydroCAD model as a starting point, we modeled the proposed Lot 1 development as follows: · The approved model included 6,200 sf of building, driveway and common drive (5,000 sf allotment +1,200 sf). The proposed development includes 7,200 sf (6,000 sf building and driveway +1,200 sf) · The approved model included a drainage area of 33,953 sf associated with lot one, comprised as shown below. The proposed lot 1 development was modeled with the same overall drainage area and the covers shown below in Table 1. Table 1 – Drainage area components Impervious Woods Open space Total Approved model 6,200 sf 27,753 sf 0 33,953 sf Post development 7,200 sf 2,243 sf 24,610 sf 33,953 sf · Times of concentration are taken from the approved model with the exception of the cleared lot, driveway and majority of the building (area P1). This area is given a Tc of 6 minutes. August 17, 2022 1093 Westhampton Road Page 2 of 2 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The site is modeled as two drainage areas: Area P1 includes the area tributary to the stormwater swale. This includes the driveway, a portion of the common driveway and 2,600 sf of the proposed house. Also included is 18,800 sf of cleared area (grass) and 2,143 sf of wooded area. Area P2 includes a portion of the house roof (800 sf) which is directed to a subsurface chamber and 5,800 sf of cleared area. Area P2 is the portion of the development which sheet flows downstream. A leaching system (SC-740) is included in this area to store and infiltrate the roof runoff. The leaching system has a capacity of approximately 75 cf allowing it to capture and infiltrate more than 1” of runoff from the tributary roof area. For simplicity, the chamber is not modeled. Table 1 below summarizes the peak flows which result from the proposed Lot 1 development: Table 2 – ‘South’ Outflow Storm Event 1-year 2-year 10-year 100-year Pre-development 1.3 cfs 2.0 cfs 4.9 cfs 9.0 cfs Post-development 1.3 cfs 1.9 cfs 4.4 cfs 7.8 cfs The HydroCAD model results find that all peak flows from the development are below the pre-development levels. If you have any questions, please do not hesitate to contact me at (413) 582-7000 or lucy@berkshiredesign.com. Sincerely, Berkshire Design Group, Inc. Lucy Conley, P.E. Civil Engineer DD94 89 90 9192 93 X9 0 . 5 91X91.5X91.9DA-P1DA-P2DA-P1 +P2 extents matchesapproved drainage model (33,953 sf)Existing swale and overflowProposed swale extensionExisting 6" low flow outlet pipeand level spreader - see stormwaterplan for required improvementsInstall HDPE cap with 4" orifice toend of 6" HDPE pipe.Tie to 6" pipe Fernco.92 Checked 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.Web: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignDo not scale drawing for quantity take-offs or construction. Usewritten dimensions only. If dimensions are incomplete, contactThe Berkshire Design Group Inc. for clarification.Land SurveyingCopyright The Berkshire Design Group, Inc.This drawing and all of its contents are the express property ofThe Berkshire Design Group, Inc., and shall not be copied orused in any way without the written consent of The BerkshireDesign Group, Inc.cTimothy J. Seney1093 Westhampton RoadFlorence, MA1093 Westhampton RoadStormwater AnalysisFigure 1Figure 1August 17, 20221" = 30'LCCC 1TS DA-TS(s) P1 Pr bldg, driveway and common drive P2 Pr bldg part, septic field 1Sa OF - Slope 1Sb LS - Slope 9CS Combined south 1Pa Drive swale Routing Diagram for Proposed model Prepared by Berkshire Design Group, Printed 8/17/2022 HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type III 24-hr 1-year Rainfall=2.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 2HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1TS: DA-TS(s) Runoff = 0.79 cfs @ 12.35 hrs, Volume= 0.101 af, Depth= 0.57" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 1-year Rainfall=2.50" Area (sf) CN Description * 93,171 73 Woods, fair, HSG C 93,171 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Subcatchment P1: Pr bldg, driveway and common drive Runoff = 0.75 cfs @ 12.10 hrs, Volume= 0.055 af, Depth= 1.06" Routed to Pond 1Pa : Drive swale Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 1-year Rainfall=2.50" Area (sf) CN Description * 2,143 73 woods, fair, HSG C * 6,400 98 impervious 18,760 79 50-75% Grass cover, Fair, HSG C 27,303 83 Weighted Average 20,903 76.56% Pervious Area 6,400 23.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: Pr bldg part, septic field Runoff = 0.11 cfs @ 12.31 hrs, Volume= 0.012 af, Depth= 0.94" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 1-year Rainfall=2.50" Area (sf) CN Description * 800 98 imp lot & common drives 5,850 79 50-75% Grass cover, Fair, HSG C 6,650 81 Weighted Average 5,850 87.97% Pervious Area 800 12.03% Impervious Area Type III 24-hr 1-year Rainfall=2.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 3HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Reach 1Sa: OF - Slope Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.00 fps, Min. Travel Time= 0.0 min Avg. Velocity = 0.00 fps, Avg. Travel Time= 0.0 min Peak Storage= 0 cf @ 0.00 hrs Average Depth at Peak Storage= 0.00' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 99.59 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 250.0' Slope= 0.2200 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' ‡ Summary for Reach 1Sb: LS - Slope Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 1.06" for 1-year event Inflow = 0.39 cfs @ 12.27 hrs, Volume= 0.055 af Outflow = 0.39 cfs @ 12.31 hrs, Volume= 0.055 af, Atten= 0%, Lag= 2.4 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 2.87 fps, Min. Travel Time= 1.3 min Avg. Velocity = 1.31 fps, Avg. Travel Time= 2.8 min Peak Storage= 30 cf @ 12.28 hrs Average Depth at Peak Storage= 0.07' , Surface Width= 2.72' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 106.17 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 220.0' Slope= 0.2500 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' Type III 24-hr 1-year Rainfall=2.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 4HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC ‡ Summary for Reach 9CS: Combined south Inflow Area = 2.918 ac, 5.66% Impervious, Inflow Depth = 0.69" for 1-year event Inflow = 1.28 cfs @ 12.34 hrs, Volume= 0.168 af Outflow = 1.28 cfs @ 12.34 hrs, Volume= 0.168 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6P Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Pond 1Pa: Drive swale Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 1.06" for 1-year event Inflow = 0.75 cfs @ 12.10 hrs, Volume= 0.055 af Outflow = 0.39 cfs @ 12.27 hrs, Volume= 0.055 af, Atten= 48%, Lag= 10.4 min Primary = 0.39 cfs @ 12.27 hrs, Volume= 0.055 af Routed to Reach 1Sb : LS - Slope Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Reach 1Sa : OF - Slope Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 89.62' @ 12.27 hrs Surf.Area= 658 sf Storage= 280 cf Plug-Flow detention time= 5.9 min calculated for 0.055 af (100% of inflow) Center-of-Mass det. time= 5.4 min ( 850.6 - 845.2 ) Volume Invert Avail.Storage Storage Description #1 88.50' 1,252 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) 88.50 10 14.0 0 0 10 89.00 176 146.0 38 38 1,691 90.00 1,110 336.0 576 614 8,983 90.50 1,448 342.0 638 1,252 9,348 Device Routing Invert Outlet Devices #1 Device 2 88.60'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 88.52'6.0" Round Culvert L= 100.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 88.52' / 85.52' S= 0.0300 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #3 Secondary 89.95'17.0' long (Profile 16) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 Coef. (English) 3.80 4.26 Type III 24-hr 1-year Rainfall=2.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 5HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Primary OutFlow Max=0.39 cfs @ 12.27 hrs HW=89.62' (Free Discharge) 2=Culvert (Passes 0.39 cfs of 0.87 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.39 cfs @ 4.44 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=88.50' (Free Discharge) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 2-year Rainfall=3.00"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 6HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1TS: DA-TS(s) Runoff = 1.28 cfs @ 12.33 hrs, Volume= 0.153 af, Depth= 0.86" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 2-year Rainfall=3.00" Area (sf) CN Description * 93,171 73 Woods, fair, HSG C 93,171 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Subcatchment P1: Pr bldg, driveway and common drive Runoff = 1.04 cfs @ 12.09 hrs, Volume= 0.076 af, Depth= 1.45" Routed to Pond 1Pa : Drive swale Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 2-year Rainfall=3.00" Area (sf) CN Description * 2,143 73 woods, fair, HSG C * 6,400 98 impervious 18,760 79 50-75% Grass cover, Fair, HSG C 27,303 83 Weighted Average 20,903 76.56% Pervious Area 6,400 23.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: Pr bldg part, septic field Runoff = 0.15 cfs @ 12.31 hrs, Volume= 0.017 af, Depth= 1.31" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 2-year Rainfall=3.00" Area (sf) CN Description * 800 98 imp lot & common drives 5,850 79 50-75% Grass cover, Fair, HSG C 6,650 81 Weighted Average 5,850 87.97% Pervious Area 800 12.03% Impervious Area Type III 24-hr 2-year Rainfall=3.00"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 7HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Reach 1Sa: OF - Slope Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 0.00 fps, Min. Travel Time= 0.0 min Avg. Velocity = 0.00 fps, Avg. Travel Time= 0.0 min Peak Storage= 0 cf @ 0.00 hrs Average Depth at Peak Storage= 0.00' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 99.59 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 250.0' Slope= 0.2200 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' ‡ Summary for Reach 1Sb: LS - Slope Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 1.45" for 2-year event Inflow = 0.45 cfs @ 12.33 hrs, Volume= 0.076 af Outflow = 0.45 cfs @ 12.37 hrs, Volume= 0.076 af, Atten= 0%, Lag= 2.2 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 2.99 fps, Min. Travel Time= 1.2 min Avg. Velocity = 1.40 fps, Avg. Travel Time= 2.6 min Peak Storage= 33 cf @ 12.35 hrs Average Depth at Peak Storage= 0.08' , Surface Width= 2.82' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 106.17 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 220.0' Slope= 0.2500 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' Type III 24-hr 2-year Rainfall=3.00"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 8HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC ‡ Summary for Reach 9CS: Combined south Inflow Area = 2.918 ac, 5.66% Impervious, Inflow Depth = 1.01" for 2-year event Inflow = 1.88 cfs @ 12.33 hrs, Volume= 0.245 af Outflow = 1.88 cfs @ 12.33 hrs, Volume= 0.245 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6P Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Pond 1Pa: Drive swale Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 1.45" for 2-year event Inflow = 1.04 cfs @ 12.09 hrs, Volume= 0.076 af Outflow = 0.45 cfs @ 12.33 hrs, Volume= 0.076 af, Atten= 57%, Lag= 14.2 min Primary = 0.45 cfs @ 12.33 hrs, Volume= 0.076 af Routed to Reach 1Sb : LS - Slope Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routed to Reach 1Sa : OF - Slope Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 89.89' @ 12.33 hrs Surf.Area= 968 sf Storage= 500 cf Plug-Flow detention time= 8.0 min calculated for 0.075 af (100% of inflow) Center-of-Mass det. time= 7.6 min ( 843.7 - 836.0 ) Volume Invert Avail.Storage Storage Description #1 88.50' 1,252 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) 88.50 10 14.0 0 0 10 89.00 176 146.0 38 38 1,691 90.00 1,110 336.0 576 614 8,983 90.50 1,448 342.0 638 1,252 9,348 Device Routing Invert Outlet Devices #1 Device 2 88.60'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 88.52'6.0" Round Culvert L= 100.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 88.52' / 85.52' S= 0.0300 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #3 Secondary 89.95'17.0' long (Profile 16) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 Coef. (English) 3.80 4.26 Type III 24-hr 2-year Rainfall=3.00"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 9HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Primary OutFlow Max=0.45 cfs @ 12.33 hrs HW=89.89' (Free Discharge) 2=Culvert (Passes 0.45 cfs of 1.00 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.45 cfs @ 5.10 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=88.50' (Free Discharge) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10-year Rainfall=4.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 10HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1TS: DA-TS(s) Runoff = 3.05 cfs @ 12.31 hrs, Volume= 0.338 af, Depth= 1.90" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 10-year Rainfall=4.50" Area (sf) CN Description * 93,171 73 Woods, fair, HSG C 93,171 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Subcatchment P1: Pr bldg, driveway and common drive Runoff = 1.96 cfs @ 12.09 hrs, Volume= 0.142 af, Depth= 2.73" Routed to Pond 1Pa : Drive swale Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 10-year Rainfall=4.50" Area (sf) CN Description * 2,143 73 woods, fair, HSG C * 6,400 98 impervious 18,760 79 50-75% Grass cover, Fair, HSG C 27,303 83 Weighted Average 20,903 76.56% Pervious Area 6,400 23.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: Pr bldg part, septic field Runoff = 0.30 cfs @ 12.30 hrs, Volume= 0.032 af, Depth= 2.55" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 10-year Rainfall=4.50" Area (sf) CN Description * 800 98 imp lot & common drives 5,850 79 50-75% Grass cover, Fair, HSG C 6,650 81 Weighted Average 5,850 87.97% Pervious Area 800 12.03% Impervious Area Type III 24-hr 10-year Rainfall=4.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 11HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Reach 1Sa: OF - Slope Inflow = 1.54 cfs @ 12.12 hrs, Volume= 0.022 af Outflow = 1.29 cfs @ 12.16 hrs, Volume= 0.022 af, Atten= 16%, Lag= 2.8 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 4.13 fps, Min. Travel Time= 1.0 min Avg. Velocity = 1.76 fps, Avg. Travel Time= 2.4 min Peak Storage= 89 cf @ 12.15 hrs Average Depth at Peak Storage= 0.14' , Surface Width= 3.77' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 99.59 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 250.0' Slope= 0.2200 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' ‡ Summary for Reach 1Sb: LS - Slope Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 2.29" for 10-year event Inflow = 0.47 cfs @ 12.12 hrs, Volume= 0.120 af Outflow = 0.47 cfs @ 12.17 hrs, Volume= 0.120 af, Atten= 0%, Lag= 2.9 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 3.04 fps, Min. Travel Time= 1.2 min Avg. Velocity = 1.59 fps, Avg. Travel Time= 2.3 min Peak Storage= 34 cf @ 12.13 hrs Average Depth at Peak Storage= 0.08' , Surface Width= 2.85' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 106.17 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 220.0' Slope= 0.2500 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' Type III 24-hr 10-year Rainfall=4.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 12HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC ‡ Summary for Reach 9CS: Combined south Inflow Area = 2.918 ac, 5.66% Impervious, Inflow Depth = 2.10" for 10-year event Inflow = 4.40 cfs @ 12.24 hrs, Volume= 0.512 af Outflow = 4.40 cfs @ 12.24 hrs, Volume= 0.512 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6P Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Pond 1Pa: Drive swale Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 2.73" for 10-year event Inflow = 1.96 cfs @ 12.09 hrs, Volume= 0.142 af Outflow = 2.02 cfs @ 12.12 hrs, Volume= 0.141 af, Atten= 0%, Lag= 1.5 min Primary = 0.47 cfs @ 12.12 hrs, Volume= 0.120 af Routed to Reach 1Sb : LS - Slope Secondary = 1.54 cfs @ 12.12 hrs, Volume= 0.022 af Routed to Reach 1Sa : OF - Slope Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 90.04' @ 12.12 hrs Surf.Area= 1,132 sf Storage= 653 cf Plug-Flow detention time= 11.7 min calculated for 0.141 af (99% of inflow) Center-of-Mass det. time= 7.8 min ( 825.6 - 817.8 ) Volume Invert Avail.Storage Storage Description #1 88.50' 1,252 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) 88.50 10 14.0 0 0 10 89.00 176 146.0 38 38 1,691 90.00 1,110 336.0 576 614 8,983 90.50 1,448 342.0 638 1,252 9,348 Device Routing Invert Outlet Devices #1 Device 2 88.60'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 88.52'6.0" Round Culvert L= 100.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 88.52' / 85.52' S= 0.0300 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #3 Secondary 89.95'17.0' long (Profile 16) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 Coef. (English) 3.80 4.26 Type III 24-hr 10-year Rainfall=4.50"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 13HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Primary OutFlow Max=0.47 cfs @ 12.12 hrs HW=90.03' (Free Discharge) 2=Culvert (Passes 0.47 cfs of 1.06 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.47 cfs @ 5.40 fps) Secondary OutFlow Max=1.35 cfs @ 12.12 hrs HW=90.03' (Free Discharge) 3=Broad-Crested Rectangular Weir (Weir Controls 1.35 cfs @ 1.05 fps) Type III 24-hr 100-year Rainfall=6.40"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 14HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Summary for Subcatchment 1TS: DA-TS(s) Runoff = 5.61 cfs @ 12.30 hrs, Volume= 0.610 af, Depth= 3.42" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 100-year Rainfall=6.40" Area (sf) CN Description * 93,171 73 Woods, fair, HSG C 93,171 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Subcatchment P1: Pr bldg, driveway and common drive Runoff = 3.16 cfs @ 12.09 hrs, Volume= 0.233 af, Depth= 4.46" Routed to Pond 1Pa : Drive swale Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 100-year Rainfall=6.40" Area (sf) CN Description * 2,143 73 woods, fair, HSG C * 6,400 98 impervious 18,760 79 50-75% Grass cover, Fair, HSG C 27,303 83 Weighted Average 20,903 76.56% Pervious Area 6,400 23.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment P2: Pr bldg part, septic field Runoff = 0.49 cfs @ 12.29 hrs, Volume= 0.054 af, Depth= 4.25" Routed to Reach 9CS : Combined south Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type III 24-hr 100-year Rainfall=6.40" Area (sf) CN Description * 800 98 imp lot & common drives 5,850 79 50-75% Grass cover, Fair, HSG C 6,650 81 Weighted Average 5,850 87.97% Pervious Area 800 12.03% Impervious Area Type III 24-hr 100-year Rainfall=6.40"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 15HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 21.4 Direct Entry, From approved model Summary for Reach 1Sa: OF - Slope Inflow = 2.61 cfs @ 12.10 hrs, Volume= 0.062 af Outflow = 2.49 cfs @ 12.12 hrs, Volume= 0.062 af, Atten= 5%, Lag= 1.4 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 4.91 fps, Min. Travel Time= 0.8 min Avg. Velocity = 2.38 fps, Avg. Travel Time= 1.8 min Peak Storage= 132 cf @ 12.11 hrs Average Depth at Peak Storage= 0.18' , Surface Width= 4.30' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 99.59 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 250.0' Slope= 0.2200 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' ‡ Summary for Reach 1Sb: LS - Slope Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 3.28" for 100-year event Inflow = 0.48 cfs @ 12.10 hrs, Volume= 0.171 af Outflow = 0.48 cfs @ 12.14 hrs, Volume= 0.171 af, Atten= 0%, Lag= 2.2 min Routed to Reach 9CS : Combined south Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Max. Velocity= 3.06 fps, Min. Travel Time= 1.2 min Avg. Velocity = 1.75 fps, Avg. Travel Time= 2.1 min Peak Storage= 34 cf @ 12.11 hrs Average Depth at Peak Storage= 0.08' , Surface Width= 2.86' Bank-Full Depth= 1.00' Flow Area= 6.7 sf, Capacity= 106.17 cfs 10.00' x 1.00' deep Parabolic Channel, n= 0.035 Earth, dense weeds Length= 220.0' Slope= 0.2500 '/' Inlet Invert= 85.00', Outlet Invert= 30.00' Type III 24-hr 100-year Rainfall=6.40"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 16HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC ‡ Summary for Reach 9CS: Combined south Inflow Area = 2.918 ac, 5.66% Impervious, Inflow Depth = 3.69" for 100-year event Inflow = 7.75 cfs @ 12.25 hrs, Volume= 0.898 af Outflow = 7.75 cfs @ 12.25 hrs, Volume= 0.898 af, Atten= 0%, Lag= 0.0 min Routed to nonexistent node 6P Routing by Stor-Ind+Trans method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Summary for Pond 1Pa: Drive swale Inflow Area = 0.627 ac, 23.44% Impervious, Inflow Depth = 4.46" for 100-year event Inflow = 3.16 cfs @ 12.09 hrs, Volume= 0.233 af Outflow = 3.09 cfs @ 12.10 hrs, Volume= 0.234 af, Atten= 2%, Lag= 0.5 min Primary = 0.48 cfs @ 12.10 hrs, Volume= 0.171 af Routed to Reach 1Sb : LS - Slope Secondary = 2.61 cfs @ 12.10 hrs, Volume= 0.062 af Routed to Reach 1Sa : OF - Slope Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 90.07' @ 12.10 hrs Surf.Area= 1,153 sf Storage= 691 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 6.3 min ( 810.1 - 803.8 ) Volume Invert Avail.Storage Storage Description #1 88.50' 1,252 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) 88.50 10 14.0 0 0 10 89.00 176 146.0 38 38 1,691 90.00 1,110 336.0 576 614 8,983 90.50 1,448 342.0 638 1,252 9,348 Device Routing Invert Outlet Devices #1 Device 2 88.60'4.0" Vert. Orifice/Grate C= 0.600 Limited to weir flow at low heads #2 Primary 88.52'6.0" Round Culvert L= 100.0' CPP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 88.52' / 85.52' S= 0.0300 '/' Cc= 0.900 n= 0.010 PVC, smooth interior, Flow Area= 0.20 sf #3 Secondary 89.95'17.0' long (Profile 16) Broad-Crested Rectangular Weir Head (feet) 0.49 0.98 Coef. (English) 3.80 4.26 Type III 24-hr 100-year Rainfall=6.40"Proposed model Printed 8/17/2022Prepared by Berkshire Design Group Page 17HydroCAD® 10.20-2d s/n 00752 © 2021 HydroCAD Software Solutions LLC Primary OutFlow Max=0.48 cfs @ 12.10 hrs HW=90.07' (Free Discharge) 2=Culvert (Passes 0.48 cfs of 1.08 cfs potential flow) 1=Orifice/Grate (Orifice Controls 0.48 cfs @ 5.49 fps) Secondary OutFlow Max=2.59 cfs @ 12.10 hrs HW=90.07' (Free Discharge) 3=Broad-Crested Rectangular Weir (Weir Controls 2.59 cfs @ 1.30 fps) D D D EXTEND STORMWATER SWALE TO SOUTH BASEMENT FFE=96.0 GFE = 102.5 FFE = 103.5 94 8990919293X90.5TOP OF BERM ELEV = 90.5 MIN 91X91.5 PR GRASS SWALE PR SEPTIC SYSTEM (SEE SEPTIC SYSTEM DESIGN PLAN) PR BUILDING EX LIMITS OF CLEARING ////////////////X91.9 INSTALL CAP WITH 4" ORIFICE ON END OF EXISTING 6" HDPE PIPE REBUILD EXISTING LEVEL SPREADER WITH LEVEL OUTLET. FILL DEPRESSIONS DOWNSTREAM WITH COMPACTED CRUSHED ROCK. INSTALL EROSION CONTROL FENCE OR FILTER BERM INSTALL ONE SC-740 CHAMBER FOR ROOF DRAINAGE. SEE SEPTIC SYSTEM NOTES 92Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. © Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The Berkshire Design Group, Inc.F:\NORTHAMPTON - 1093 WESTHAMPTON RD\02-DESIGN PROCESS\04-DRAWINGS\1093 WESTHAMPTON STORMWATER PERMIT PLAN.DWG PLOT DATE: 8/17/20221093 Westhampton Road Site Stormwater Plan Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Land Surveying Timothy J. Seney 1093 Westhampton Road Florence, MA 0 40'20'10'60' C-1August 17, 2022 1" =20' LC CC EXISTING CONDITIONS NOTES 1.THE EXISTING CONDITIONS DEPICTED HEREON WERE OBTAINED BY A FIELD SURVEY IN 2018 BY JAMES GRACIA. 2.LOCATION OF 6" LOW FLOW OUTLET AND LEVEL SPREADER WERE NOT SURVEYED AND ARE APPROXIMATE. 3.THIS PLAN IS PREPARED AS A SITE DESIGN AND IS NOT INTENDED TO BE USED FOR DETERMINATION OF PROPERTY LINES. 4.THE CONTRACTOR SHALL FIELD VERIFY ALL EXISTING CONDITIONS. IF A DISCREPANCY IS FOUND BETWEEN THIS PLAN AND THE ACTUAL FIELD CONDITION, THE CONTRACTOR SHALL IMMEDIATELY NOTIFY THE LANDSCAPE ARCHITECT. EROSION CONTROL NOTES 1.THE CONTRACTOR SHALL INSTALL EROSION CONTROL DEVICES AS NECESSARY TO PREVENT EROSION WITHIN THE SITE AND MIGRATION OF SEDIMENT OUT OF THE SITE, OR AS DIRECTED BY THE ENGINEER. ALL DEVICES SHALL COMPLY WITH THE MASSACHUSETTS EROSION AND SEDIMENT CONTROL GUIDELINES, CURRENT VERSION. 2.THE PROPOSED PROJECT IS SUBJECT TO PERMITTING BY THE CITY OF NORTHAMPTON UNDER THE NORTHAMPTON STORMWATER PERMIT. THE CONTRACTOR SHALL COMPLY WITH ALL CONDITIONS OF THE STORMWATER PERMIT. 3.THE CONTRACTOR SHALL INSPECT ALL INSTALLED EROSION CONTROL DEVICES AT LEAST WEEKLY AND AFTER EACH STORM. IF ANY DEVICE IS FOUND TO BE DAMAGED, THE CONTRACTOR SHALL REPAIR IT IMMEDIATELY. IF SEDIMENT IS FOUND TO FILL MORE THAN HALF THE HEIGHT OF THE DEVICE, THE SEDIMENT SHALL BE REMOVED OR THE DEVICE REPLACED. 4.ALL VEHICLES ENTERING AND EXITING THE SITE SHALL BE REQUIRED TO CROSS A TRACKING PAD TO PREVENT TRACKING OF SEDIMENT ONTO PUBLIC ROADWAYS. IF SEDIMENT IS FOUND ON ROADWAYS, THE SEDIMENT SHALL BE REMOVED IMMEDIATELY. 5.THE CONTRACTOR SHALL INSTALL EROSION CONTROL BARRIER ALONG ALL DOWN-SLOPE SITE LIMITS TO PREVENT THE MIGRATION OF SEDIMENT OFF-SITE. 6.ALL SEDIMENT STOCKPILES SHALL BE SURROUNDED BY A CONTINUOUS SILT FENCE. IF THE STOCKPILE WILL REMAIN UNUSED FOR MORE THAN 30 DAYS, THE STOCKPILE SHALL BE STABILIZED BY SEEDING. 6.THE CONTRACTOR SHALL MAINTAIN A STOCKPILE OF EXTRA EROSION CONTROL MATERIALS ON SITE AT ALL TIMES. 7.THE CONTRACTOR SHALL IMPLEMENT SPILL-PREVENTION PROCEDURES AND MAINTAIN A SPILL PREVENTION AND CLEANUP PLAN FOR THE SITE. ALL MATERIALS THAT ARE CAPABLE OF SPILLING, LEAKING, DISSOLVING OR OTHERWISE POLLUTING STORMWATER RUNOFF SHALL BE COVERED WHILE STORED AT THE SITE. 8.ALL MATERIALS THAT ARE CAPABLE OF SPILLING, LEAKING, DISSOLVING OR OTHERWISE POLLUTING STORMWATER RUNOFF SHALL BE COVERED WHILE STORED AT THE SITE. 9.ALL SEDIMENT REMOVED FROM THE SITE SHALL BE HANDLED IN ACCORDANCE WITH STATE AND LOCAL REGULATIONS. 10.ALL TEMPORARY EROSION CONTROLS SHALL BE REMOVED FROM THE SITE PRIOR TO THE COMPLETION OF THE WORK, EXCEPT WHERE DEGRADABLE MATERIALS ARE TO REMAIN IN-PLACE PERMANENTLY. 11.ALL SLOPES OVER 3:1 SLOPE SHALL BE COVERED WITH ECSC-2B DOUBLE STRAW NET AND SEEDED WITH AN EROSION CONTROL MIX FOR DRY SITES. BOTH AVAILABLE FROM NEW ENGLAND WETLAND PLANTS, AMHERST, MA. 50' min. 8"min. PUBLIC ROAD GEOTEXTILE SEPARATION FABRIC 2"-3'' WASHED COARSE EXIST. GROUND FOR FULL WIDTH AND LENGTH AGGREGATE STABILIZED CONSTRUCTION ACCESS NOTES: 1. DIMENSIONS:WIDTH: 15' FLARED TO 25' AT ROADWAY LENGTH: 50' MIN. GRADE AND CROSS SLOPE: 2% 2. CLEAR ACCESS OF ALL VEGETATION, ROOTS, AND OTHER OBJECTIONAL MATERIAL. 3. GRAVEL PAD SUBGRADE SHALL BE GRADED SO THAT THE ACCESS WILL NOT DRAIN OFF SITE. 4. MAINTAIN THE GRAVEL PAD IN A CONDITION TO PREVENT MUD, SEDIMENT, ETC. FROM LEAVING THE SITE. SHOULD MUD/SEDIMENT BE TRACKED OR WASHED INTO THE PUBLIC ROAD IT SHALL BE REMOVED IMMEDIATELY. SECTION ORGANIC FILTER BERM4NOT TO SCALE ORGANIC FILTER BERM NOTES: 1.ORGANIC FILTER BERMS MAY BE UTILIZED IN LIEU OF SILT FENCE. 2.THE EROSION CONTROL MIX USED IN THE FILTER BERMS SHALL BE A WELL-GRADED MIXTURE OF PARTICLE SIZES, MAY CONTAIN ROCKS LESS THAN 4 IN DIAMETER, STUMP GRINDINGS, SHREDDED OR COMPOSED BARK, OR ACCEPTABLE MANUFACTURED PRODUCTS, AND SHALL BE FREE OF REFUSE AND PHYSICAL CONTAMINANTS, AND MATERIAL TOXIC TO PLAN GROWTH. IT SHALL MEET THE FOLLOWING STANDARDS: A.THE ORGANIC CONTENT SHALL BE 80-100% BY DRY WEIGHT. B.PARTICLE SIZE BY WEIGHT SHALL BE 100% PASSING A 6" SCREEN AND 70-85% PASSING A 0.75" SCREEN. C.THE ORGANIC PORTION SHALL BE FIBROUS AND ELONGATED. D.LARGE PORTIONS OF SILTS, CLAYS, OR FINE SANDS SHALL NOT BE INCLUDED IN THE MIXTURES. 3.ORGANIC FILTER BERMS SHALL BE INSTALLED ALONG A RELATIVELY LEVEL CONTOUR. IT MAY BE NECESSARY TO CUT TALL GRASSES OR WOODY VEGETATION TO AVOID CREATING VOIDS AND BRIDGES THAT WOULD ENABLE FINES TO WASH UNDER THE BERM. 4.FROZEN GROUND, OUTCROPS OF BEDROCK, AND VERY ROOTED FORESTED AREAS PRESENT THE MOST PRACTICAL AND EFFECTIVE LOCATIONS FOR ORGANIC FILTER BERMS. OTHER BMPS SHOULD BE USED AT LOW POINTS OF CONCENTRATED RUNOFF, BELOW CULVERT OUTLET APRONS, AROUND CATCH BASINS AND AT THE BOTTOM OF STEEP PERIMETER SLOPES THAT HAVE A LARGE CONTRIBUTING AREA. 5.SEDIMENT SHALL BE REMOVED FROM BEHIND THE STRUCTURES WHEN IT HAS ACCUMULATED TO ONE HALF THE ORIGINAL HEIGHT OF THE STRUCTURE. 6.STRUCTURES MAY BE LEFT IN PLACE ONE THE SITE IS STABILIZED. ADJACENT ROLLS SHALLTIGHTLY ABUT 12" DIA. STRAW WATTLES SECTION SILT FENCE TUCKED UNDER STRAW WATTLE SILT FENCE SILT FENCE ENTRENCHED 3" FLOW EROSION CONTROL BARRIER2NOT TO SCALE STABILIZED CONSTRUCTION ENTRANCE1NOT TO SCALE WORK AREA AREA TO BE PROTECTED 3' (MIN)1.5'MIN1 1 ELEV. VARIES 3" SIDESLOPE (SEE PLAN) LOAM & SEED (SEE NOTE) STORMWATER SWALE3NOT TO SCALE NOTES: 1.SEED SIDES AND BOTTOM OF SWALE WITH "NEW ENGLAND EROSION CONTROL/RESTORATION MIX FOR DETENTION BASINS AND MOIST SITES" MIX FROM NEW ENGLAND WETLANDS PLANTS. 2.PROTECT BASIN FROM RUNOFF UNTIL THE TRIBUTARY AREA IS STABILIZED AND A VIABLE VEGETATIVE COVER HAS BEEN ACHIEVED WITHIN THE RAIN GARDEN. 3.LOAM FOR BOTTOM OF SWALE SHALL BE A MIX OF 40% CLEAN SAND, 20% TOPSOIL, 40% COMPOST.