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20-0518 - Burts Bog Dev SW Analysis w connection to BP
4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group May 18, 2020 Doug McDonald Stormwater Manager Northampton DPW RE: Burts Bog Conservation & Limited Development Project Burts Pit Road (Map 29, Lot 10) Stormwater Analysis with Connection to Burts Pit Storm Drain Dear Doug: Berkshire Design Group (BDG) has completed an analysis of the Burts Bog Development Project with a connection to the Burts Pit Road storm drain to reduce the stormwater volume runoff associated with the development. Previously we had submitted a plan which reduced the peak flows to pre-development rates but did not reduce volumes to pre-development conditions. The addition of dry wells to infiltrate the home roofs was considered to reduce volumes. However, because of the poor soils and high groundwater conditions at the site, the dry wells were very large and there was concern over their proper function as well as maintenance. Burts Pit Road Drainage System Capacity In March we began the discussion of connecting to the Burts Pit Road storm drain to reduce the volume of runoff from the site. We completed an analysis of the Burts Pit Road drainage system which showed that the storm drain has excess capacity throughout for the 25-year storm event. For the 100-year storm event, the system also has excess capacity with the exception of the 16’ outfall pipe. This section is currently under- capacity for the 100-year storm event and stormwater backs up into the upstream manhole. Modeling with hydroCAD, indicates that stormwater backs up into the upstream manhole to a depth of 4.4’ to elev 253.6. Since the as-built drawings show a depth from invert to cover of 6’ (rim at 255.2), it appears that the backup of flow in the 100-year storm event is contained within the drainage system. See Appendix A for the summary of flow and HydroCAD model. The model assumes a rounded edge connection of the pipe within the manhole. Current Subdivision Plan and Proposed Drainage In March, we also presented a draft revised plan with new footprints for the homes on lots 4, 6 and 8 along with the architectural rendering of the proposed homes. The revised plan showed a significant increase in impervious area based on those footprints. In conjunction with the developer and the architect, we have now revised the buildings and the parking to smaller footprints. Figure 1 shows the new building configurations, parking, and walkways. Proposed grading is shown on Figure 2. We have also reconfigured the drainage model to reflect this layout and recalculated all the impervious areas proposed. This layout results in an increase of less than 500 sf from the layout submitted in the fall of 2019. The increase includes walkways to the entrances of the new buildings. Because of the difficulty of siting dry wells within C and D soils and a shallow groundwater table, the dry wells are no longer proposed and are therefore not modeled. We do propose to maintain the gravel diaphragms on the edges of driveways for water quality. The large shallow (<2’) detention areas are maintained with some minor grading changes. Please see Figure 3 for the revised proposed hydrology. May 18, 2020 Burts Bog Conservation & Limited Development Project Burts Pit Road (Map 29, Lot 10) Stormwater Analysis with connection to Burts Pit Storm Drain Page 2 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Design of Flow diversion to Burts Pit Road Drainage System The revised drainage design includes a flow diversion to Burts Pit Road. The Design is detailed on Figure 1 and includes a diversion manhole within the Lot 3/4/6 driveway to capture a portion of the pond outflow. The water is then routed to Burts Pit Road. At Burts Pit Road the existing catch basin on the north side of the street is proposed to be relocated 10 feet upstream so that a new manhole can be installed in that location (in the shoulder) and reuse the existing piping within Burts Pit Road. Since Burts Pit road has been recently repaved this would result in very little disturbance of the new paving. Three manholes and the new or relocated catch basin would be required under this proposed design. Revised Peak Flows and Volumes for Development The following tables outline peak flows and volumes at the east and west control points with the diversion to the Burts Pit drainage system. Diverted flows and volumes are also listed. The HydroCAD models are attached in Appendix B. Table 1. Runoff Summary Table for Individual Control Points Condition & Point of Analysis 2-Year Storm 3.05” 10-Year Storm 4.47” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing To West Property Line (CP1) 2.56 6.12 15.84 Proposed To West Property Line (CP1) 2.34 5.08 12.57 Diverted to Burts Pit Road 0.34 0.79 1.02 Existing To East Property Line (CP2) 0.38 0.87 2.21 Proposed To East Property Line (CP2) 0.38 0.81 2.17 May 18, 2020 Burts Bog Conservation & Limited Development Project Burts Pit Road (Map 29, Lot 10) Stormwater Analysis with connection to Burts Pit Storm Drain Page 3 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 2. Runoff Summary Table For Each Discharge Point Condition & Point of Analysis 2-Year Storm 3.05” 10-Year Storm 4.47” 100-Year Storm 7.68” Runoff Volume (acre-feet) Runoff Volume (acre-feet) Runoff Volume (acre-feet) Existing (CP1) 0.260 0.559 1.393 Proposed (CP1) 0.242 0.489 1.163 Volume diverted 0.064 0.116 0.233 Existing (CP2) 0.034 0.073 0.182 Proposed (CP2) 0.059 0.125 0.303 The analysis shows that all peak flows and volumes to Control Point 1 are below the values in existing conditions. Peak flows to the east are controlled to existing conditions. However, as in the previous report, runoff volumes exceed conditions at this control point Analysis of flow diversion to the Burts Pit Road Drainage System As previously reported, the Burts Pit road drainage system has the excess capacity with the exception of the outfall pipe in the 100-year storm event. Calculations show an underszizing of the system for the last 16’ and pressure flow with ponding in the last manhole of 4.4’. The HydroCAD model was used to model conditions with an additional 1 cfs peak flow. (see Appendix C). The modeling shows that the elevation within the manhole increases 0.5’ to an elevation of 254.10, leaving approximately 1.1’ of freeboard. Assuming the catch basin rims are no lower than 1.1’ of the manhole rim, there should not be any significant ponding at the low point in Burts Pit Road because of the undercapacity of this pipe in the 100-year storm event. Conclusion The revised plan for the Burts Pit Road development results in a small increase to the impervious area total presented last September. The original design concept of two large shallow detention areas is maintained with the addition of a base flow diversion of the runoff to the west. It is proposed that this flow be diverted into the Burts Pit Road drainage system. The small diverted flow proposed can be accommodated within this drainage system with only minor change to existing conditions. If you have any questions or comments on this analysis, please do not hesitate to contact me. Sincerely, Lucy Conley, P.E. Berkshire Design Group Burts Pit RoadMHSSSWoodsWoodsWoodsWoodsWoodsWoodsPaintedWater LineSMHRim=310.29'TBM=Top SpindleOf HydrantEl: 312.49'TBM=Top SpindleOf HydrantEl: 314.83'OHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWCBRim=311.61'CBRim=311.48'MHRim=311.72'SMHRim=312.64'TBM=Railroad SpikeSouth Side UP#72/72El: 315.77'SMHRim=313.51'BituminousDriveway BituminousDrivewayBituminousDrivewayBituminousDrivewayEdge Of PavementEdge Of PavementEdge Of PavementEdge Of PavementBituminous CurbBituminous Concrete3203153163173183193143153103113123133073083093 1 4 3 1 5 3 1 6317318 3 1 9 3 2 0 321 3 2 2 3 2 3 313314312313314315320323312312313314315308309310311312 313314314313314314313312311310313310309Single FamHouseSingle FamHouseWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSShedShedShedShedGarage GarageUNIT 2900 SF2 BEDUNIT 1800 SF1 BEDUNIT 31000 SF3 BEDSingle Fam w/accessory AptGarageSingle FamHouseShedShedShedGarageSingle FamHouseSingle FamHouse (2 bed)Single FamHouse (1 bed)Single FamHouse (3 bed)Lot 1Lot 2Lot 3Lot 4Lot 5Lot 6Lot 7Lot 9Lot 8Lot 10FFE 312.75FFE 313.75FFE 315.75FFE 313.75FFE 314.75FFE 314.75FFE 315.0GFE 314.25Single Fam w/accessory AptSingle Fam w/accessory AptDDDDDDDCity Of NorthamptonBurts Bog Greenway114.76 Acres4999121.41 Sq. FeetRAINGARDEN(3) 8" DUCTILE IRON DRAIN PIPESINVERT IN = 307.8INVERT OUT = 307.5 (EXIST.)6" COVER (MIN.)RIPRAP OUTLET PROTECTION2' WIDE x 1' DEEPTRENCH FILLED WITH3/4" CRUSHED STONEEDGE OF WOODS TO REMAINSEE LIMIT OF WORK PLAN(1) 12" HDPE PIPE INVERT IN = 309.75INVERT OUT = 309.50RIPRAP OUTLETPROTECTION3'X3' OPEN CONCRETE BOXOUTLET CONTROL5" ORIFICE INV=309.80TOP OF BOX=311.0012" CULVERT OUT INV=309.753'X3' OPEN CONCRETE BOXOUTLET CONTROL5" ORIFICE INV=312.008" X 6" SLOT INV=312.50TOP OF WALL=313.20(1) 12" HDPE PIPE INVERT IN = 311.90INVERT OUT = 311.80RIPRAP OUTLET PROTECTION2' WIDE x 1' DEEPTRENCH FILLED WITH3/4" CRUSHED STONE2' WIDE x 1' DEEPTRENCH FILLED WITH3/4" CRUSHED STONEPROP. PLANTINGS(SEE SHEET L-1)NO DISTURB ZONE FORSTORMWATER MANAGEMENTPROTECT DURING CONSTRUCTIONEND PROP. ASPHALT CURBTIE TO EXISTING.(APPROX. LOCATION)INSTALL ASPHALT CURB ATEDGE OF PAVEMENT (TYP.ALL FRONTAGE)BEGIN PROPOSED ASPHALTCURB. TIE TO EXISTING CURB.APPROX. LOCATION.2' WIDE x 1' DEEPTRENCH FILLED WITH3/4" CRUSHED STONEPR DMH #2 INVERT IN = 308.30INVERT OUT = 308.20 PR DMH #1 INVERT IN = 309.7INVERT OUT (12")= 309.6INVERT OUT (10") W/ 6" ORIFICEPLATE=309.6130 LF 10" H D P E @ 1 %PR DMH #3INVERT IN (2)= 307.60INVERT OUT = 307.3060 LF 10" HDPE @ 1%PR REPLACEMENT CB10"INVERT OUT = 307.70EX. CB RIM 311.48 - INV 307.15 (DPW RECORDS)RELOCATE EXISTING CATCHBASIN 10' EASTEXTEND 10" RCP TO PR DMH #3 AT EX. SLOPE (2.5%±)MH INV 305.0 (BASEDON DPW CHECK)10" INV IN 306.4Checked 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 EngineeringPlanningDo 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.cLOT 29-10BURTS PIT ROADBerkshireGroupDesignPROPOSED DRAINAGEIMPROVEMENTSFIG 1MAY 17, 20201"=40'LMCMBD0804020120 Single FamHouseSingle FamHouseWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSShedShedShedShedGarage GarageSingle Fam w/accessory AptGarageSingle FamHouseShedShedShedGarageSingle FamHouseSingle FamHouse (2 bed)Single FamHouse (1 bed)Single FamHouse (3 bed)FFE 312.75FFE 313.75FFE 315.75FFE 313.75FFE 314.75FFE 314.75FFE 315.0GFE 314.25Single Fam w/accessory AptSingle Fam w/accessory AptDDDDDDDBurts Pit RoadMHSSSDirtPileDirtPileDirtPileArea OfMultipleDebris PilesPaintedWater LineSMHRim=310.29'GuyPoleUP #73.5/73-50TBM=Top SpindleOf HydrantEl: 312.49'OHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWOHWCBRim=311.61'CBRim=311.48'MHRim=311.72'UP #73/73SMHRim=312.64'UP #72/72TBM=Railroad SpikeSouth Side UP#72/72El: 315.77'SMHRim=313.51'(NEW) UP #71w/Transformer& Utility BoxesGuyWires(Old) UP #714" Gas LineAs MarkedBituminousDriveway BituminousDrivewayBituminousDrivewayBituminousDrivewayEdge Of PavementEdge Of PavementEdge Of PavementEdge Of PavementBituminous CurbBituminous Concrete3153163173183193143153103113123133073083093 1 4 3 1 5 3 1 6317 31 8 31 9 32 0 321 3223 2 3 313314312313314315320323312312313314315308309310311312 313314314313314314313312311310313310309City Of NorthamptonBurts Bog Greenway114.76 Acres4999121.41 Sq. FeetMAINTAINNATURALSWALEMAINTAIN NATURAL SWALEEXCEPT AT DRIVEWAY CROSSINGS312.30313.75313.5312.5312.50312.50312.30314.0313.0312.1312.25312.5312.75313.25313.75312309308309 3133 1 3 312313311 3143153123133103113123103113 1 2 312312311313314314313312.5312.5312.8DRIVEWAYS SHALL SLOPE UP FROM CURB LINETO PROPERTY LINE AT 3% (MIN.)TO PREVENT STORMWATERRUN-ON FROM ROADWAY; DRIVEWAYSWITHIN THE PROPERTY SHALL BE GRADED TODRAIN TO INTERIOR OF THE SITE (TYP. OF ALL)ALL FRONT YARD AREAS SHALL BEGRADED TO DRAIN TO THEINTERIOR OF THE SITE.2' WIDE, 12" DEEP TRENCHFILLED WITH 3/4" CRUSHED STONESHALLOW DETENTION AREA 2BERM ELEV = 313.50SLOPE DRIVEWAY EAST TODETENTION AREASLOPE DRIVEWAY EAST TODETENTION AREA.SHALLOW DETENTIONAREA 1DRIVEWAY AREA NORTH OF THIS LINE SHALL DRAIN TO DETENTION AREA 1.DRIVEWAY AREA SOUTH OF THIS LINE SHALLDRAIN WEST.DRIVEWAY SHALL SLOPE NORTH AND SHEETFLOW TO DETENTION AREA 1.Lot 1Lot 3Lot 5Lot 7Lot 9Lot 10Lot 8Lot 6Lot 4Lot 22' WIDE, 12" DEEP TRENCHFILLED WITH 3/4" CRUSHED STONENO DISTURB ZONE FORSTORMWATER MANAGEMENTPROTECT DURING CONSTRUCTIONSLOPE DRIVEWAY WESTPROPOSED SHRUBS/SCREENING (TYP)0' ZONING SETBACK15' ZONING SETBACK20' ADDITIONAL SETBACK45' ADDITIONAL SETBACK30' ZONING SETBACK40' ADDITIONAL SETBACK PROPOSED SHRUBS/SCREENING (TYP)0804020120Checked 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 EngineeringPlanningDo 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.cLOT 29-10BURTS PIT ROADBerkshireGroupDesignMAY 17, 20201"=40'LMCMBDFIG 2PROPOSED GRADING Single Fam House Single Fam House ShedSh e d Shed Sh e d GarageGarage D D D Singl e F a m w / acces s o r y A p t Ga r a g e Sin g l e F a m Ho u s e Sh e d Sh e d Sh e d Ga r a g e Sin g l e F a m Ho u s e Sin g l e F a m Ho u s e ( 2 b e d ) Sin g l e F a m Ho u s e ( 1 b e d ) Sin g l e F a m Ho u s e ( 3 b e d ) D FFE 3 1 2 . 7 5 FFE 3 1 3 . 7 5 FF E 3 1 5 . 7 5 FFE 3 1 3 . 7 5 FF E 3 1 4 . 7 5 FFE 3 1 4 . 7 5 FF E 3 1 5 . 0 GF E 3 1 4 . 2 5 Si n g l e F a m w / ac c e s s o r y A p t Singl e F a m w / acces s o r y A p t DDDDDDDDDD D D D Burts Pit Road Public Right Of Way ~ 49.5' Wide MH S S S Painted Water Line SMH Rim=310.29' Gas Test Valve Guy Wire Guy Pole UP #73.5/73-50 OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW CBRim=311.61' CB Rim=311.48' MHRim=311.72' UP #73/73 SMHRim=312.64' UP #72/72 SMHRim=313.51' (NEW) UP #71 w/Transformer & Utility Boxes Guy Wires (Old) UP #71 4" Gas Line As Marked BituminousDrivewayBituminousDrivewayBituminousDrivewayBituminousDrivewayEdge Of Pavement Edge Of Pavement Edge Of Pavement Edge Of Pavement Bituminous Curb Bituminous Concrete 320 315 316 317 318 319 3 1 4 3 1 5 3103113 1 2 3 1 3 30730 8 309314 315 316 317 318319320321322323 313 314 312 313 314 315 320 323312312313314315308309310311 312313 314 314 3 1 3 314 314313 312 311 3 1 0 3 0 9 313 3 1 0 30 9 Burts Pit Road Public Right Of Way ~ 49.5' Wide MH S S S Painted Water Line SMH Rim=310.29' Gas Test Valve Guy Wire Guy Pole UP #73.5/73-50 OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW OHW CBRim=311.61' CB Rim=311.48' MHRim=311.72' UP #73/73 SMHRim=312.64' UP #72/72 SMHRim=313.51' (NEW) UP #71 w/Transformer & Utility Boxes Guy Wires (Old) UP #71 4" Gas Line As Marked BituminousDrivewayBituminousDrivewayBituminousDrivewayBituminousDrivewayEdge Of Pavement Edge Of Pavement Edge Of Pavement Edge Of Pavement Bituminous Curb Bituminous Concrete 320 315 316 317 318 319 3 1 4 3 1 5 3103113 1 2 3 1 3 30730 8 309314 315 316 317 318319320321322323 313 314 312 313 314 315 320 323312312313314315308309310311 312313 314 314 3 1 3 314 314313 312 311 3 1 0 3 0 9 313 3 1 0 30 9 X (3) 8" D.I. DRAIN PIPES 314313 OUTLET CONTROL OUTLET CONTROL LIMIT OF WOODS TO REMAIN Lot 1 Lot 2 Lot 3 Lot 4 Lot 5 Lot 6 Lot 7 Lot 9 Lot 8 Lot 10 313.5312.5312309 308309313313312313311314 31 5 312313310 311 312 310 31 1 312312312 31131331 4 31 4 313 CP1 A2 TOT: 35,100 SF IM: 2,055 SF WD: 26,605 SF GR: 6,440 SF A1 TOT: 22,050SF IM: 5,292 SF WD: 4,064 SF GR: 12,694 SF A4 TOT: 7,295 SF IM: 2,337 SF GR: 4,958 SF A5 TOT: 77,645 SF IMP: 12,815 SF WD: 29,024 SF GR: 35,806 SF A6 TOT: 35,330 SF IMP: 3,660 SF WD: 18,659 SF GR: 13,011 SF CP2 DETENTION - 1 A3 TOT: 9,300 SF IM: 1,808 SF GR: 7,492 SF DETENTION - 2 SWALE 1 SWALE 2 IM: 770 SF I M : 5 4 2 S F IM: 2,060SF IM : 1 , 2 6 4 S F I M : 1, 0 0 0 S F I M : 90 0 S F IM:3,020 SF I M : 4 0 0 S F IM : 2, 3 0 0 S F I M : 4 0 0 S F IM: 1,030 SFIM : 7 2 2 S F IM: 2,180 SFIM : 1, 4 2 0 S F IM: 2,180 SFIM: 695SFIM: 530 SFIM : 1 , 6 5 2 S F IM: 1 , 6 5 2 S F IM: 1 , 6 5 2 S F Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The Berkshire Design Group, Inc. c LOT 29-10 BURTS PIT ROAD Landscape Architecture Civil Engineering Planning Berkshire Group Design Land Surveying FIG 3 MAY 17, 2020 1"=50' LMC PROPOSED HYDROLOGY 0 1005025 150 LEGEND TOT: TOTAL AREA IM: IMPERVIOUS WD: WOODED GR: GRASS CP: CONTROL POINT (ALL AREAS SHOWN IN SQUARE FEET) MBD Appendix A Burts Pit Drainage System 100-year Storm Capacity Summary and HydroCAD Model 3. Existing Flow and Capacity Calculations - 100 year stormContributing Areas/StructuresTotal Area(sf)Impervious Area(sf)% ImperviousRunoff Coefficient 'C'Coefficient Ca 5RainfallIntensity 'I'(100-Year Storm)DrainageArea 'A'(acres)Flow Rate (cfs) Q=CaCIASize(in)Length(ft)Slope 3(%)Capacity(cfs)Excess Capacity (cfs)DMH1DMH2A850380960.950.871.258.80.201.86123192.9%6.084.22DMH2DMH3A+B23718187840.790.751.258.50.544.36123503.9%7.052.69DMH3DMH4A+B+C65154349950.540.581.258.31.508.94153602.6%10.521.59DMH4DMH5A+B+C+D78082462270.590.611.2581.7911.01152553.5%12.151.14DMH5DMH6A+B+C+D+E92894551120.590.621.257.82.1312.79153314.7%14.041.25DMH6OutletA+B+C+D+E+F121443698980.580.601.257.62.7915.9715164.7%14.04-1.933 from 1969 as-built4 rainfall intensity from Exhibit 8-15 IDF curve for Springfield, MA (Chapter 8, MDOT Design Guide)5 Ca is an additional factor for storm events over the 10-year storm (see Chapter 8, MADOT Design Guide). Rainfall Duration=8 min, Inten=7.60 in/hrrational Printed 5/18/2020Prepared by Berkshire Design Group Page 1HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond DMH: Drainage MH #6 Burts Pit Road Inflow Area = 121,532 sf, 0.00% Impervious, Inflow Depth = 0.76" Inflow = 15.86 cfs @ 0.13 hrs, Volume= 7,695 cf Outflow = 15.73 cfs @ 0.13 hrs, Volume= 7,695 cf, Atten= 1%, Lag= 0.1 min Primary = 15.73 cfs @ 0.13 hrs, Volume= 7,695 cf Routing by Stor-Ind method, Time Span= 0.00-3.00 hrs, dt= 0.01 hrs Peak Elev= 253.63' @ 0.13 hrs Surf.Area= 13 sf Storage= 56 cf Plug-Flow detention time= 0.0 min calculated for 7,669 cf (100% of inflow) Center-of-Mass det. time= 0.0 min ( 8.0 - 8.0 ) Volume Invert Avail.Storage Storage Description #1 249.20' 75 cf 4.00'D x 6.00'H Vertical Cone/Cylinder Device Routing Invert Outlet Devices #1 Primary 249.20'15.0" Round Culvert L= 16.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 249.20' / 248.45' S= 0.0469 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=15.57 cfs @ 0.13 hrs HW=253.56' (Free Discharge) 1=Culvert (Inlet Controls 15.57 cfs @ 12.69 fps) Pond DMH: Drainage MH #6 Burts Pit Road Inflow Primary Hydrograph Time (hours) 3210Flow (cfs)17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=121,532 sf Peak Elev=253.63' Storage=56 cf 15.0" Round Culvert n=0.013 L=16.0' S=0.0469 '/' 15.86 cfs15.73 cfs Appendix B Burts Pit Development Revised HydroCAD Models A6 General Drainage Area CP2 CP2 2P DETENTION AREA - EAST Routing Diagram for Burts Meadow PR EAST 2020 Prepared by Berkshire Design Group, Printed 5/18/2020 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.299 74 >75% Grass cover, Good, HSG C (A6) 0.084 98 IMPERVIOUS (A6) 0.428 70 Woods, Good, HSG C (A6) 0.811 74 TOTAL AREA Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 0.000 HSG A 0.000 HSG B 0.727 HSG C A6 0.000 HSG D 0.084 Other A6 0.811 TOTAL AREA NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A6: General Drainage Area Runoff = 0.81 cfs @ 12.18 hrs, Volume= 0.064 af, Depth= 0.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description * 3,660 98 IMPERVIOUS 13,011 74 >75% Grass cover, Good, HSG C 18,659 70 Woods, Good, HSG C 35,330 74 Weighted Average 31,670 89.64% Pervious Area 3,660 10.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.6 430 0.0405 0.75 Lag/CN Method, Contour Length= 1,431' Interval= 1' Subcatchment A6: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=35,330 sf Runoff Volume=0.064 af Runoff Depth=0.95" Flow Length=430' Slope=0.0405 '/' Tc=9.6 min CN=74 0.81 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP2: CP2 Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 0.88" for 2-Year event Inflow = 0.38 cfs @ 12.35 hrs, Volume= 0.059 af Outflow = 0.38 cfs @ 12.35 hrs, Volume= 0.059 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Reach CP2: CP2 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.811 ac 0.38 cfs0.38 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: DETENTION AREA - EAST Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 0.95" for 2-Year event Inflow = 0.81 cfs @ 12.18 hrs, Volume= 0.064 af Outflow = 0.39 cfs @ 12.35 hrs, Volume= 0.064 af, Atten= 52%, Lag= 10.3 min Discarded = 0.01 cfs @ 12.35 hrs, Volume= 0.005 af Primary = 0.38 cfs @ 12.35 hrs, Volume= 0.059 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Peak Elev= 312.52' @ 12.35 hrs Surf.Area= 1,891 sf Storage= 518 cf Plug-Flow detention time= 35.3 min calculated for 0.064 af (100% of inflow) Center-of-Mass det. time= 35.1 min ( 916.4 - 881.3 ) Volume Invert Avail.Storage Storage Description #1 312.00' 3,249 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 312.00 248 71.0 0 0 248 312.50 1,824 163.0 457 457 1,962 313.00 3,200 230.0 1,240 1,697 4,060 313.40 4,600 280.0 1,552 3,249 6,092 Device Routing Invert Outlet Devices #1 Primary 311.90'12.0" Round Culvert L= 10.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 311.90' / 311.80' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 312.00'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 312.50'8.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 313.20'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #5 Discarded 312.00'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.01 cfs @ 12.35 hrs HW=312.52' (Free Discharge) 5=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.38 cfs @ 12.35 hrs HW=312.52' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 0.38 cfs of 1.18 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.37 cfs @ 2.71 fps) 3=Orifice/Grate (Orifice Controls 0.01 cfs @ 0.50 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: DETENTION AREA - EAST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.811 ac Peak Elev=312.52' Storage=518 cf 0.81 cfs 0.39 cfs 0.01 cfs 0.38 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A6: General Drainage Area Runoff = 1.73 cfs @ 12.17 hrs, Volume= 0.132 af, Depth= 1.95" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description * 3,660 98 IMPERVIOUS 13,011 74 >75% Grass cover, Good, HSG C 18,659 70 Woods, Good, HSG C 35,330 74 Weighted Average 31,670 89.64% Pervious Area 3,660 10.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.6 430 0.0405 0.75 Lag/CN Method, Contour Length= 1,431' Interval= 1' Subcatchment A6: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=35,330 sf Runoff Volume=0.132 af Runoff Depth=1.95" Flow Length=430' Slope=0.0405 '/' Tc=9.6 min CN=74 1.73 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP2: CP2 Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 1.85" for 10-Year event Inflow = 0.81 cfs @ 12.33 hrs, Volume= 0.125 af Outflow = 0.81 cfs @ 12.33 hrs, Volume= 0.125 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Reach CP2: CP2 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.811 ac 0.81 cfs0.81 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: DETENTION AREA - EAST Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 1.95" for 10-Year event Inflow = 1.73 cfs @ 12.17 hrs, Volume= 0.132 af Outflow = 0.82 cfs @ 12.33 hrs, Volume= 0.132 af, Atten= 52%, Lag= 9.7 min Discarded = 0.02 cfs @ 12.33 hrs, Volume= 0.007 af Primary = 0.81 cfs @ 12.33 hrs, Volume= 0.125 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Peak Elev= 312.78' @ 12.33 hrs Surf.Area= 2,586 sf Storage= 1,144 cf Plug-Flow detention time= 29.7 min calculated for 0.132 af (100% of inflow) Center-of-Mass det. time= 29.5 min ( 887.1 - 857.6 ) Volume Invert Avail.Storage Storage Description #1 312.00' 3,249 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 312.00 248 71.0 0 0 248 312.50 1,824 163.0 457 457 1,962 313.00 3,200 230.0 1,240 1,697 4,060 313.40 4,600 280.0 1,552 3,249 6,092 Device Routing Invert Outlet Devices #1 Primary 311.90'12.0" Round Culvert L= 10.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 311.90' / 311.80' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 312.00'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 312.50'8.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 313.20'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #5 Discarded 312.00'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.02 cfs @ 12.33 hrs HW=312.78' (Free Discharge) 5=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.81 cfs @ 12.33 hrs HW=312.78' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 0.81 cfs of 2.06 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.49 cfs @ 3.63 fps) 3=Orifice/Grate (Orifice Controls 0.31 cfs @ 1.69 fps) 4=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: DETENTION AREA - EAST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=0.811 ac Peak Elev=312.78' Storage=1,144 cf 1.73 cfs 0.82 cfs 0.02 cfs 0.81 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A6: General Drainage Area Runoff = 4.11 cfs @ 12.17 hrs, Volume= 0.314 af, Depth= 4.64" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description * 3,660 98 IMPERVIOUS 13,011 74 >75% Grass cover, Good, HSG C 18,659 70 Woods, Good, HSG C 35,330 74 Weighted Average 31,670 89.64% Pervious Area 3,660 10.36% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.6 430 0.0405 0.75 Lag/CN Method, Contour Length= 1,431' Interval= 1' Subcatchment A6: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=35,330 sf Runoff Volume=0.314 af Runoff Depth=4.64" Flow Length=430' Slope=0.0405 '/' Tc=9.6 min CN=74 4.11 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 13HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP2: CP2 Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 4.48" for 100-Year event Inflow = 2.17 cfs @ 12.30 hrs, Volume= 0.303 af Outflow = 2.17 cfs @ 12.30 hrs, Volume= 0.303 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Reach CP2: CP2 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=0.811 ac 2.17 cfs2.17 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 14HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: DETENTION AREA - EAST Inflow Area = 0.811 ac, 10.36% Impervious, Inflow Depth = 4.64" for 100-Year event Inflow = 4.11 cfs @ 12.17 hrs, Volume= 0.314 af Outflow = 2.20 cfs @ 12.30 hrs, Volume= 0.314 af, Atten= 46%, Lag= 7.9 min Discarded = 0.03 cfs @ 12.30 hrs, Volume= 0.011 af Primary = 2.17 cfs @ 12.30 hrs, Volume= 0.303 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 3 Peak Elev= 313.26' @ 12.30 hrs Surf.Area= 4,109 sf Storage= 2,704 cf Plug-Flow detention time= 25.0 min calculated for 0.314 af (100% of inflow) Center-of-Mass det. time= 24.9 min ( 855.0 - 830.0 ) Volume Invert Avail.Storage Storage Description #1 312.00' 3,249 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 312.00 248 71.0 0 0 248 312.50 1,824 163.0 457 457 1,962 313.00 3,200 230.0 1,240 1,697 4,060 313.40 4,600 280.0 1,552 3,249 6,092 Device Routing Invert Outlet Devices #1 Primary 311.90'12.0" Round Culvert L= 10.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 311.90' / 311.80' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 0.79 sf #2 Device 1 312.00'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 312.50'8.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 313.20'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #5 Discarded 312.00'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.03 cfs @ 12.30 hrs HW=313.26' (Free Discharge) 5=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=2.17 cfs @ 12.30 hrs HW=313.26' TW=0.00' (Dynamic Tailwater) 1=Culvert (Passes 2.17 cfs of 3.47 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.67 cfs @ 4.94 fps) 3=Orifice/Grate (Orifice Controls 1.13 cfs @ 3.40 fps) 4=Broad-Crested Rectangular Weir (Weir Controls 0.37 cfs @ 0.68 fps) NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR EAST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 15HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: DETENTION AREA - EAST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 Inflow Area=0.811 ac Peak Elev=313.26' Storage=2,704 cf 4.11 cfs 2.20 cfs 0.03 cfs 2.17 cfs A1 General Drainage Area A2 General Drainage Area A3 General Drainage Area A4 General Drainage Area A5 General Drainage Area CP1 Control Point 1 S1 Swale Segment S2 Swale Segment 1P DETENTION AREA - WEST 2P CB Diversion MH Routing Diagram for Burts Meadow PR WEST 2020 Prepared by Berkshire Design Group, Printed 5/18/2020 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 1.547 74 >75% Grass cover, Good, HSG C (A1, A2, A3, A4, A5) 0.558 98 Paved parking, HSG C (A1, A2, A3, A4, A5) 1.370 70 Woods, Good, HSG C (A1, A2, A5) Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pipe Listing (all nodes) Line# Node Number In-Invert (feet) Out-Invert (feet) Length (feet) Slope (ft/ft) n Diam/Width (inches) Height (inches) Inside-Fill (inches) 1 1P 309.80 309.70 10.0 0.0100 0.012 12.0 0.0 0.0 2 2P 309.60 309.50 10.0 0.0100 0.012 12.0 0.0 0.0 NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A1: General Drainage Area Runoff = 0.79 cfs @ 12.13 hrs, Volume= 0.052 af, Depth= 1.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 5,292 98 Paved parking, HSG C 4,064 70 Woods, Good, HSG C 12,694 74 >75% Grass cover, Good, HSG C 22,050 79 Weighted Average 16,758 76.00% Pervious Area 5,292 24.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 275 0.0380 0.77 Lag/CN Method, Tc Contour Length= 838' Interval= 1' Subcatchment A1: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=22,050 sf Runoff Volume=0.052 af Runoff Depth=1.24" Flow Length=275' Slope=0.0380 '/' Tc=6.0 min CN=79 0.79 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A2: General Drainage Area Runoff = 0.71 cfs @ 12.18 hrs, Volume= 0.057 af, Depth= 0.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 2,055 98 Paved parking, HSG C 26,605 70 Woods, Good, HSG C 6,440 74 >75% Grass cover, Good, HSG C 35,100 72 Weighted Average 33,045 94.15% Pervious Area 2,055 5.85% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 395 0.0407 0.70 Lag/CN Method, Tc Contour Length= 1,430' Interval= 1' Subcatchment A2: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=35,100 sf Runoff Volume=0.057 af Runoff Depth=0.85" Flow Length=395' Slope=0.0407 '/' Tc=9.5 min CN=72 0.71 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A3: General Drainage Area Runoff = 0.35 cfs @ 12.13 hrs, Volume= 0.022 af, Depth= 1.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,808 98 Paved parking, HSG C 7,492 74 >75% Grass cover, Good, HSG C 9,300 79 Weighted Average 7,492 80.56% Pervious Area 1,808 19.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 218 0.0375 0.73 Lag/CN Method, Tc Contour Length= 349' Interval= 1' Subcatchment A3: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=9,300 sf Runoff Volume=0.022 af Runoff Depth=1.24" Flow Length=218' Slope=0.0375 '/' Tc=5.0 min CN=79 0.35 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A4: General Drainage Area Runoff = 0.33 cfs @ 12.12 hrs, Volume= 0.020 af, Depth= 1.43" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 2,337 98 Paved parking, HSG C 4,958 74 >75% Grass cover, Good, HSG C 7,295 82 Weighted Average 4,958 67.96% Pervious Area 2,337 32.04% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.0 Direct Entry, Subcatchment A4: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=7,295 sf Runoff Volume=0.020 af Runoff Depth=1.43" Tc=4.0 min CN=82 0.33 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A5: General Drainage Area Runoff = 2.07 cfs @ 12.17 hrs, Volume= 0.158 af, Depth= 1.06" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 12,815 98 Paved parking, HSG C 29,024 70 Woods, Good, HSG C 35,806 74 >75% Grass cover, Good, HSG C 77,645 76 Weighted Average 64,830 83.50% Pervious Area 12,815 16.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 400 0.0348 0.72 Lag/CN Method, Tc Contour Length= 2,700' Interval= 1' Subcatchment A5: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=77,645 sf Runoff Volume=0.158 af Runoff Depth=1.06" Flow Length=400' Slope=0.0348 '/' Tc=9.2 min CN=76 2.07 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP1: Control Point 1 [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 3.475 ac, 16.06% Impervious, Inflow Depth = 0.83" for 2-Year event Inflow = 2.34 cfs @ 12.14 hrs, Volume= 0.242 af Outflow = 2.34 cfs @ 12.14 hrs, Volume= 0.242 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Reach CP1: Control Point 1 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=3.475 ac 2.34 cfs2.34 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S1: Swale Segment Inflow Area = 2.163 ac, 18.00% Impervious, Inflow Depth = 0.73" for 2-Year event Inflow = 0.93 cfs @ 12.13 hrs, Volume= 0.132 af Outflow = 0.91 cfs @ 12.14 hrs, Volume= 0.132 af, Atten= 2%, Lag= 0.7 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 0.90 fps, Min. Travel Time= 1.3 min Avg. Velocity = 0.39 fps, Avg. Travel Time= 3.0 min Peak Storage= 70 cf @ 12.14 hrs Average Depth at Peak Storage= 0.10' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 142.77 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 70.0' Slope= 0.0129 '/' Inlet Invert= 307.40', Outlet Invert= 306.50' ‡ Reach S1: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=2.163 ac Avg. Flow Depth=0.10' Max Vel=0.90 fps n=0.030 L=70.0' S=0.0129 '/' Capacity=142.77 cfs 0.93 cfs0.91 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S2: Swale Segment Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 0.61" for 2-Year event Inflow = 0.54 cfs @ 12.35 hrs, Volume= 0.090 af Outflow = 0.53 cfs @ 12.37 hrs, Volume= 0.090 af, Atten= 1%, Lag= 1.4 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 0.86 fps, Min. Travel Time= 1.7 min Avg. Velocity = 0.42 fps, Avg. Travel Time= 3.6 min Peak Storage= 56 cf @ 12.37 hrs Average Depth at Peak Storage= 0.07' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 167.89 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 90.0' Slope= 0.0178 '/' Inlet Invert= 309.40', Outlet Invert= 307.80' ‡ Reach S2: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.782 ac Avg. Flow Depth=0.07' Max Vel=0.86 fps n=0.030 L=90.0' S=0.0178 '/' Capacity=167.89 cfs 0.54 cfs0.53 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: DETENTION AREA - WEST Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 1.06" for 2-Year event Inflow = 2.07 cfs @ 12.17 hrs, Volume= 0.158 af Outflow = 0.91 cfs @ 12.35 hrs, Volume= 0.158 af, Atten= 56%, Lag= 10.9 min Discarded = 0.02 cfs @ 12.35 hrs, Volume= 0.004 af Primary = 0.88 cfs @ 12.35 hrs, Volume= 0.154 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 311.04' @ 12.35 hrs Surf.Area= 2,469 sf Storage= 1,249 cf Plug-Flow detention time= 13.7 min calculated for 0.158 af (100% of inflow) Center-of-Mass det. time= 13.7 min ( 887.4 - 873.6 ) Volume Invert Avail.Storage Storage Description #1 309.80' 9,251 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 309.80 5 1.0 0 0 5 310.00 200 65.0 16 16 341 311.00 2,286 213.0 1,054 1,070 3,618 312.00 6,658 395.0 4,282 5,352 12,429 312.50 9,000 450.0 3,900 9,251 16,134 Device Routing Invert Outlet Devices #1 Primary 309.80'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.80' / 309.70' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Device 1 309.80'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 311.00'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #4 Discarded 309.80'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.02 cfs @ 12.35 hrs HW=311.04' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.88 cfs @ 12.35 hrs HW=311.04' TW=309.99' (Dynamic Tailwater) 1=Culvert (Passes 0.88 cfs of 3.41 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.67 cfs @ 4.89 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 0.21 cfs @ 0.57 fps) NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 13HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: DETENTION AREA - WEST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=1.782 ac Peak Elev=311.04' Storage=1,249 cf 2.07 cfs 0.91 cfs 0.02 cfs 0.88 cfs NRCC 24-hr C 2-Year Rainfall=3.07"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 14HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Diversion MH [57] Hint: Peaked at 309.99' (Flood elevation advised) Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 1.04" for 2-Year event Inflow = 0.88 cfs @ 12.35 hrs, Volume= 0.154 af Outflow = 0.88 cfs @ 12.35 hrs, Volume= 0.154 af, Atten= 0%, Lag= 0.0 min Discarded = 0.34 cfs @ 12.35 hrs, Volume= 0.064 af Primary = 0.54 cfs @ 12.35 hrs, Volume= 0.090 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 309.99' @ 12.35 hrs Device Routing Invert Outlet Devices #1 Primary 309.60'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.60' / 309.50' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Discarded 309.60'6.0" Vert. Orifice/Grate C= 0.600 Discarded OutFlow Max=0.34 cfs @ 12.35 hrs HW=309.99' (Free Discharge) 2=Orifice/Grate (Orifice Controls 0.34 cfs @ 2.12 fps) Primary OutFlow Max=0.54 cfs @ 12.35 hrs HW=309.99' TW=309.47' (Dynamic Tailwater) 1=Culvert (Barrel Controls 0.54 cfs @ 2.85 fps) Pond 2P: Diversion MH Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.782 ac Peak Elev=309.99' 0.88 cfs0.88 cfs 0.34 cfs 0.54 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 15HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A1: General Drainage Area Runoff = 1.51 cfs @ 12.13 hrs, Volume= 0.099 af, Depth= 2.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 5,292 98 Paved parking, HSG C 4,064 70 Woods, Good, HSG C 12,694 74 >75% Grass cover, Good, HSG C 22,050 79 Weighted Average 16,758 76.00% Pervious Area 5,292 24.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 275 0.0380 0.77 Lag/CN Method, Tc Contour Length= 838' Interval= 1' Subcatchment A1: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=22,050 sf Runoff Volume=0.099 af Runoff Depth=2.35" Flow Length=275' Slope=0.0380 '/' Tc=6.0 min CN=79 1.51 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 16HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A2: General Drainage Area Runoff = 1.58 cfs @ 12.17 hrs, Volume= 0.121 af, Depth= 1.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 2,055 98 Paved parking, HSG C 26,605 70 Woods, Good, HSG C 6,440 74 >75% Grass cover, Good, HSG C 35,100 72 Weighted Average 33,045 94.15% Pervious Area 2,055 5.85% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 395 0.0407 0.70 Lag/CN Method, Tc Contour Length= 1,430' Interval= 1' Subcatchment A2: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=35,100 sf Runoff Volume=0.121 af Runoff Depth=1.80" Flow Length=395' Slope=0.0407 '/' Tc=9.5 min CN=72 1.58 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 17HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A3: General Drainage Area Runoff = 0.67 cfs @ 12.12 hrs, Volume= 0.042 af, Depth= 2.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,808 98 Paved parking, HSG C 7,492 74 >75% Grass cover, Good, HSG C 9,300 79 Weighted Average 7,492 80.56% Pervious Area 1,808 19.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 218 0.0375 0.73 Lag/CN Method, Tc Contour Length= 349' Interval= 1' Subcatchment A3: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=9,300 sf Runoff Volume=0.042 af Runoff Depth=2.35" Flow Length=218' Slope=0.0375 '/' Tc=5.0 min CN=79 0.67 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 18HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A4: General Drainage Area Runoff = 0.59 cfs @ 12.11 hrs, Volume= 0.036 af, Depth= 2.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 2,337 98 Paved parking, HSG C 4,958 74 >75% Grass cover, Good, HSG C 7,295 82 Weighted Average 4,958 67.96% Pervious Area 2,337 32.04% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.0 Direct Entry, Subcatchment A4: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=7,295 sf Runoff Volume=0.036 af Runoff Depth=2.61" Tc=4.0 min CN=82 0.59 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 19HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A5: General Drainage Area Runoff = 4.20 cfs @ 12.17 hrs, Volume= 0.313 af, Depth= 2.11" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 12,815 98 Paved parking, HSG C 29,024 70 Woods, Good, HSG C 35,806 74 >75% Grass cover, Good, HSG C 77,645 76 Weighted Average 64,830 83.50% Pervious Area 12,815 16.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 400 0.0348 0.72 Lag/CN Method, Tc Contour Length= 2,700' Interval= 1' Subcatchment A5: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=77,645 sf Runoff Volume=0.313 af Runoff Depth=2.11" Flow Length=400' Slope=0.0348 '/' Tc=9.2 min CN=76 4.20 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 20HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP1: Control Point 1 [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 3.475 ac, 16.06% Impervious, Inflow Depth = 1.69" for 10-Year event Inflow = 5.08 cfs @ 12.16 hrs, Volume= 0.489 af Outflow = 5.08 cfs @ 12.16 hrs, Volume= 0.489 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Reach CP1: Control Point 1 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Inflow Area=3.475 ac 5.08 cfs5.08 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 21HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S1: Swale Segment Inflow Area = 2.163 ac, 18.00% Impervious, Inflow Depth = 1.49" for 10-Year event Inflow = 2.84 cfs @ 12.24 hrs, Volume= 0.269 af Outflow = 2.83 cfs @ 12.25 hrs, Volume= 0.269 af, Atten= 1%, Lag= 0.7 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 1.28 fps, Min. Travel Time= 0.9 min Avg. Velocity = 0.45 fps, Avg. Travel Time= 2.6 min Peak Storage= 154 cf @ 12.25 hrs Average Depth at Peak Storage= 0.16' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 142.77 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 70.0' Slope= 0.0129 '/' Inlet Invert= 307.40', Outlet Invert= 306.50' ‡ Reach S1: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)3 2 1 0 Inflow Area=2.163 ac Avg. Flow Depth=0.16' Max Vel=1.28 fps n=0.030 L=70.0' S=0.0129 '/' Capacity=142.77 cfs 2.84 cfs2.83 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 22HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S2: Swale Segment Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 1.28" for 10-Year event Inflow = 2.40 cfs @ 12.24 hrs, Volume= 0.191 af Outflow = 2.38 cfs @ 12.25 hrs, Volume= 0.191 af, Atten= 1%, Lag= 0.9 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 1.36 fps, Min. Travel Time= 1.1 min Avg. Velocity = 0.48 fps, Avg. Travel Time= 3.1 min Peak Storage= 158 cf @ 12.25 hrs Average Depth at Peak Storage= 0.14' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 167.89 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 90.0' Slope= 0.0178 '/' Inlet Invert= 309.40', Outlet Invert= 307.80' ‡ Reach S2: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)2 1 0 Inflow Area=1.782 ac Avg. Flow Depth=0.14' Max Vel=1.36 fps n=0.030 L=90.0' S=0.0178 '/' Capacity=167.89 cfs 2.40 cfs2.38 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 23HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: DETENTION AREA - WEST Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 2.11" for 10-Year event Inflow = 4.20 cfs @ 12.17 hrs, Volume= 0.313 af Outflow = 3.22 cfs @ 12.24 hrs, Volume= 0.313 af, Atten= 23%, Lag= 4.1 min Discarded = 0.03 cfs @ 12.24 hrs, Volume= 0.006 af Primary = 3.19 cfs @ 12.24 hrs, Volume= 0.306 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 311.22' @ 12.24 hrs Surf.Area= 3,257 sf Storage= 2,021 cf Plug-Flow detention time= 13.6 min calculated for 0.313 af (100% of inflow) Center-of-Mass det. time= 13.6 min ( 864.9 - 851.4 ) Volume Invert Avail.Storage Storage Description #1 309.80' 9,251 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 309.80 5 1.0 0 0 5 310.00 200 65.0 16 16 341 311.00 2,286 213.0 1,054 1,070 3,618 312.00 6,658 395.0 4,282 5,352 12,429 312.50 9,000 450.0 3,900 9,251 16,134 Device Routing Invert Outlet Devices #1 Primary 309.80'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.80' / 309.70' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Device 1 309.80'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 311.00'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #4 Discarded 309.80'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.03 cfs @ 12.24 hrs HW=311.22' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=3.19 cfs @ 12.24 hrs HW=311.22' TW=310.54' (Dynamic Tailwater) 1=Culvert (Passes 3.19 cfs of 3.89 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.54 cfs @ 3.97 fps) 3=Broad-Crested Rectangular Weir (Weir Controls 2.65 cfs @ 1.33 fps) NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 24HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: DETENTION AREA - WEST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 Inflow Area=1.782 ac Peak Elev=311.22' Storage=2,021 cf 4.20 cfs 3.22 cfs 0.03 cfs 3.19 cfs NRCC 24-hr C 10-Year Rainfall=4.47"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 25HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Diversion MH [57] Hint: Peaked at 310.54' (Flood elevation advised) Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 2.06" for 10-Year event Inflow = 3.19 cfs @ 12.24 hrs, Volume= 0.306 af Outflow = 3.19 cfs @ 12.24 hrs, Volume= 0.306 af, Atten= 0%, Lag= 0.0 min Discarded = 0.79 cfs @ 12.24 hrs, Volume= 0.116 af Primary = 2.40 cfs @ 12.24 hrs, Volume= 0.191 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 310.54' @ 12.24 hrs Device Routing Invert Outlet Devices #1 Primary 309.60'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.60' / 309.50' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Discarded 309.60'6.0" Vert. Orifice/Grate C= 0.600 Discarded OutFlow Max=0.79 cfs @ 12.24 hrs HW=310.54' (Free Discharge) 2=Orifice/Grate (Orifice Controls 0.79 cfs @ 4.00 fps) Primary OutFlow Max=2.40 cfs @ 12.24 hrs HW=310.54' TW=309.54' (Dynamic Tailwater) 1=Culvert (Barrel Controls 2.40 cfs @ 4.06 fps) Pond 2P: Diversion MH Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)3 2 1 0 Inflow Area=1.782 ac Peak Elev=310.54' 3.19 cfs3.19 cfs 0.79 cfs 2.40 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 26HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A1: General Drainage Area Runoff = 3.27 cfs @ 12.13 hrs, Volume= 0.220 af, Depth= 5.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 5,292 98 Paved parking, HSG C 4,064 70 Woods, Good, HSG C 12,694 74 >75% Grass cover, Good, HSG C 22,050 79 Weighted Average 16,758 76.00% Pervious Area 5,292 24.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 275 0.0380 0.77 Lag/CN Method, Tc Contour Length= 838' Interval= 1' Subcatchment A1: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=22,050 sf Runoff Volume=0.220 af Runoff Depth=5.21" Flow Length=275' Slope=0.0380 '/' Tc=6.0 min CN=79 3.27 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 27HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A2: General Drainage Area Runoff = 3.92 cfs @ 12.17 hrs, Volume= 0.296 af, Depth= 4.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 2,055 98 Paved parking, HSG C 26,605 70 Woods, Good, HSG C 6,440 74 >75% Grass cover, Good, HSG C 35,100 72 Weighted Average 33,045 94.15% Pervious Area 2,055 5.85% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.5 395 0.0407 0.70 Lag/CN Method, Tc Contour Length= 1,430' Interval= 1' Subcatchment A2: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=35,100 sf Runoff Volume=0.296 af Runoff Depth=4.41" Flow Length=395' Slope=0.0407 '/' Tc=9.5 min CN=72 3.92 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 28HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A3: General Drainage Area Runoff = 1.43 cfs @ 12.12 hrs, Volume= 0.093 af, Depth= 5.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,808 98 Paved parking, HSG C 7,492 74 >75% Grass cover, Good, HSG C 9,300 79 Weighted Average 7,492 80.56% Pervious Area 1,808 19.44% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 218 0.0375 0.73 Lag/CN Method, Tc Contour Length= 349' Interval= 1' Subcatchment A3: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=9,300 sf Runoff Volume=0.093 af Runoff Depth=5.21" Flow Length=218' Slope=0.0375 '/' Tc=5.0 min CN=79 1.43 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 29HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A4: General Drainage Area Runoff = 1.22 cfs @ 12.11 hrs, Volume= 0.078 af, Depth= 5.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 2,337 98 Paved parking, HSG C 4,958 74 >75% Grass cover, Good, HSG C 7,295 82 Weighted Average 4,958 67.96% Pervious Area 2,337 32.04% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.0 Direct Entry, Subcatchment A4: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=7,295 sf Runoff Volume=0.078 af Runoff Depth=5.56" Tc=4.0 min CN=82 1.22 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 30HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment A5: General Drainage Area Runoff = 9.60 cfs @ 12.17 hrs, Volume= 0.723 af, Depth= 4.87" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 12,815 98 Paved parking, HSG C 29,024 70 Woods, Good, HSG C 35,806 74 >75% Grass cover, Good, HSG C 77,645 76 Weighted Average 64,830 83.50% Pervious Area 12,815 16.50% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.2 400 0.0348 0.72 Lag/CN Method, Tc Contour Length= 2,700' Interval= 1' Subcatchment A5: General Drainage Area Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=77,645 sf Runoff Volume=0.723 af Runoff Depth=4.87" Flow Length=400' Slope=0.0348 '/' Tc=9.2 min CN=76 9.60 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 31HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP1: Control Point 1 [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 3.475 ac, 16.06% Impervious, Inflow Depth = 4.02" for 100-Year event Inflow = 12.57 cfs @ 12.14 hrs, Volume= 1.163 af Outflow = 12.57 cfs @ 12.14 hrs, Volume= 1.163 af, Atten= 0%, Lag= 0.0 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Reach CP1: Control Point 1 Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=3.475 ac 12.57 cfs12.57 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 32HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S1: Swale Segment Inflow Area = 2.163 ac, 18.00% Impervious, Inflow Depth = 3.59" for 100-Year event Inflow = 5.72 cfs @ 12.12 hrs, Volume= 0.647 af Outflow = 5.70 cfs @ 12.13 hrs, Volume= 0.647 af, Atten= 0%, Lag= 0.4 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 1.59 fps, Min. Travel Time= 0.7 min Avg. Velocity = 0.54 fps, Avg. Travel Time= 2.2 min Peak Storage= 251 cf @ 12.13 hrs Average Depth at Peak Storage= 0.23' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 142.77 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 70.0' Slope= 0.0129 '/' Inlet Invert= 307.40', Outlet Invert= 306.50' ‡ Reach S1: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)6 5 4 3 2 1 0 Inflow Area=2.163 ac Avg. Flow Depth=0.23' Max Vel=1.59 fps n=0.030 L=70.0' S=0.0129 '/' Capacity=142.77 cfs 5.72 cfs5.70 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 33HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach S2: Swale Segment Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 3.21" for 100-Year event Inflow = 3.88 cfs @ 12.30 hrs, Volume= 0.477 af Outflow = 3.88 cfs @ 12.32 hrs, Volume= 0.477 af, Atten= 0%, Lag= 0.7 min Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Max. Velocity= 1.58 fps, Min. Travel Time= 0.9 min Avg. Velocity = 0.58 fps, Avg. Travel Time= 2.6 min Peak Storage= 221 cf @ 12.32 hrs Average Depth at Peak Storage= 0.18' Bank-Full Depth= 1.00' Flow Area= 33.3 sf, Capacity= 167.89 cfs 50.00' x 1.00' deep Parabolic Channel, n= 0.030 Earth, grassed & winding Length= 90.0' Slope= 0.0178 '/' Inlet Invert= 309.40', Outlet Invert= 307.80' ‡ Reach S2: Swale Segment Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)4 3 2 1 0 Inflow Area=1.782 ac Avg. Flow Depth=0.18' Max Vel=1.58 fps n=0.030 L=90.0' S=0.0178 '/' Capacity=167.89 cfs 3.88 cfs3.88 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 34HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: DETENTION AREA - WEST Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 4.87" for 100-Year event Inflow = 9.60 cfs @ 12.17 hrs, Volume= 0.723 af Outflow = 4.97 cfs @ 12.30 hrs, Volume= 0.723 af, Atten= 48%, Lag= 8.3 min Discarded = 0.07 cfs @ 12.30 hrs, Volume= 0.013 af Primary = 4.90 cfs @ 12.30 hrs, Volume= 0.710 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 311.92' @ 12.30 hrs Surf.Area= 6,318 sf Storage= 5,019 cf Plug-Flow detention time= 15.1 min calculated for 0.723 af (100% of inflow) Center-of-Mass det. time= 15.1 min ( 839.9 - 824.8 ) Volume Invert Avail.Storage Storage Description #1 309.80' 9,251 cf Custom Stage Data (Irregular) Listed below Elevation Surf.Area Perim. Inc.Store Cum.Store Wet.Area (feet) (sq-ft) (feet) (cubic-feet) (cubic-feet) (sq-ft) 309.80 5 1.0 0 0 5 310.00 200 65.0 16 16 341 311.00 2,286 213.0 1,054 1,070 3,618 312.00 6,658 395.0 4,282 5,352 12,429 312.50 9,000 450.0 3,900 9,251 16,134 Device Routing Invert Outlet Devices #1 Primary 309.80'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.80' / 309.70' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Device 1 309.80'5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 311.00'9.0' long x 0.5' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 #4 Discarded 309.80'0.250 in/hr Exfiltration over Wetted area Phase-In= 0.01' Discarded OutFlow Max=0.07 cfs @ 12.30 hrs HW=311.92' (Free Discharge) 4=Exfiltration (Exfiltration Controls 0.07 cfs) Primary OutFlow Max=4.90 cfs @ 12.30 hrs HW=311.92' TW=311.02' (Dynamic Tailwater) 1=Culvert (Inlet Controls 4.90 cfs @ 6.24 fps) 2=Orifice/Grate (Passes < 0.62 cfs potential flow) 3=Broad-Crested Rectangular Weir (Passes < 26.33 cfs potential flow) NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 35HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: DETENTION AREA - WEST Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.782 ac Peak Elev=311.92' Storage=5,019 cf 9.60 cfs 4.97 cfs 0.07 cfs 4.90 cfs NRCC 24-hr C 100-Year Rainfall=7.68"Burts Meadow PR WEST 2020 Printed 5/18/2020Prepared by Berkshire Design Group Page 36HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Diversion MH [57] Hint: Peaked at 311.02' (Flood elevation advised) Inflow Area = 1.782 ac, 16.50% Impervious, Inflow Depth = 4.78" for 100-Year event Inflow = 4.90 cfs @ 12.30 hrs, Volume= 0.710 af Outflow = 4.90 cfs @ 12.30 hrs, Volume= 0.710 af, Atten= 0%, Lag= 0.0 min Discarded = 1.02 cfs @ 12.30 hrs, Volume= 0.233 af Primary = 3.88 cfs @ 12.30 hrs, Volume= 0.477 af Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 311.02' @ 12.30 hrs Device Routing Invert Outlet Devices #1 Primary 309.60'12.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 309.60' / 309.50' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.79 sf #2 Discarded 309.60'6.0" Vert. Orifice/Grate C= 0.600 Discarded OutFlow Max=1.02 cfs @ 12.30 hrs HW=311.02' (Free Discharge) 2=Orifice/Grate (Orifice Controls 1.02 cfs @ 5.20 fps) Primary OutFlow Max=3.88 cfs @ 12.30 hrs HW=311.02' TW=309.58' (Dynamic Tailwater) 1=Culvert (Barrel Controls 3.88 cfs @ 4.94 fps) Pond 2P: Diversion MH Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210Flow (cfs)5 4 3 2 1 0 Inflow Area=1.782 ac Peak Elev=311.02' 4.90 cfs4.90 cfs 1.02 cfs 3.88 cfs Appendix C Burts Pit Drainage System with Diversion 100-year Storm Capacity Summary and HydroCAD Model 3. Existing Flow and Capacity Calculations - 100 year stormContributing Areas/StructuresTotal Area(sf)Impervious Area(sf)% ImperviousRunoff Coefficient 'C'Coefficient Ca 5RainfallIntensity 'I'(100-Year Storm)DrainageArea 'A'(acres)Flow Rate (cfs) Q=CaCIASize(in)Length(ft)Slope 3(%)Capacity(cfs)Excess Capacity (cfs)DMH1DMH2A850380960.950.871.258.80.201.86123192.9%6.084.22DMH2DMH3A+B23718187840.790.751.258.50.544.36123503.9%7.052.69DMH3DMH4A+B+C65154349950.540.581.258.31.508.94153602.6%10.521.59DMH4DMH5A+B+C+D78082462270.590.611.2581.7911.01152553.5%12.151.14DMH5DMH6A+B+C+D+E92894551120.590.621.257.82.1312.79153314.7%14.041.25DMH6OutletA+B+C+D+E+F121443698980.580.601.257.62.7915.9715164.7%14.04-1.933 from 1969 as-built4 rainfall intensity from Exhibit 8-15 IDF curve for Springfield, MA (Chapter 8, MDOT Design Guide)5 Ca is an additional factor for storm events over the 10-year storm (see Chapter 8, MADOT Design Guide). Rainfall Duration=8 min, Inten=7.60 in/hrrational plus diverted flow Printed 5/18/2020Prepared by Berkshire Design Group Page 1HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment 1: Burts Pit Road DA Runoff = 15.86 cfs @ 0.13 hrs, Volume= 7,695 cf, Depth= 0.76" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-3.00 hrs, dt= 0.01 hrs Rainfall Duration=8 min, Inten=7.60 in/hr Area (ac) C Description 2.790 0.75 2.790 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 7.9 Direct Entry, Subcatchment 1: Burts Pit Road DA Runoff Hydrograph Time (hours) 3210Flow (cfs)17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Rainfall Duration=8 min, Inten=7.60 in/hr Runoff Area=2.790 ac Runoff Volume=7,695 cf Runoff Depth=0.76" Tc=7.9 min C=0.75 15.86 cfs Rainfall Duration=8 min, Inten=7.60 in/hrrational plus diverted flow Printed 5/18/2020Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment 2: Burts Bog Ltd Dev Project Factor Runoff = 1.03 cfs @ 0.09 hrs, Volume= 496 cf, Depth= 0.91" Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-3.00 hrs, dt= 0.01 hrs Rainfall Duration=8 min, Inten=7.60 in/hr Area (ac) C Description 0.150 0.90 0.150 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 2: Burts Bog Ltd Dev Project Factor Runoff Hydrograph Time (hours) 3210Flow (cfs)1 0 Rainfall Duration=8 min, Inten=7.60 in/hr Runoff Area=0.150 ac Runoff Volume=496 cf Runoff Depth=0.91" Tc=5.0 min C=0.90 1.03 cfs Rainfall Duration=8 min, Inten=7.60 in/hrrational plus diverted flow Printed 5/18/2020Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond DMH: Drainage Manhole 6 - Burts Pit Road Inflow Area = 128,066 sf, 0.00% Impervious, Inflow Depth = 0.77" Inflow = 16.89 cfs @ 0.13 hrs, Volume= 8,191 cf Outflow = 16.74 cfs @ 0.13 hrs, Volume= 8,191 cf, Atten= 1%, Lag= 0.1 min Primary = 16.74 cfs @ 0.13 hrs, Volume= 8,191 cf Routing by Stor-Ind method, Time Span= 0.00-3.00 hrs, dt= 0.01 hrs Peak Elev= 254.14' @ 0.13 hrs Surf.Area= 13 sf Storage= 62 cf Plug-Flow detention time= 0.1 min calculated for 8,163 cf (100% of inflow) Center-of-Mass det. time= 0.1 min ( 7.9 - 7.9 ) Volume Invert Avail.Storage Storage Description #1 249.20' 75 cf 4.00'D x 6.00'H Vertical Cone/Cylinder Device Routing Invert Outlet Devices #1 Primary 249.20'15.0" Round Culvert L= 16.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 249.20' / 248.45' S= 0.0469 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=16.58 cfs @ 0.13 hrs HW=254.06' (Free Discharge) 1=Culvert (Inlet Controls 16.58 cfs @ 13.51 fps) Pond DMH: Drainage Manhole 6 - Burts Pit Road Inflow Primary Hydrograph Time (hours) 3210Flow (cfs)18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=128,066 sf Peak Elev=254.14' Storage=62 cf 15.0" Round Culvert n=0.013 L=16.0' S=0.0469 '/' 16.89 cfs16.74 cfs Rainfall Duration=8 min, Inten=7.60 in/hrrational plus diverted flow Printed 5/18/2020Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Link L: outfall Inflow Area = 128,066 sf, 0.00% Impervious, Inflow Depth = 0.77" Inflow = 16.74 cfs @ 0.13 hrs, Volume= 8,191 cf Primary = 16.74 cfs @ 0.13 hrs, Volume= 8,191 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-3.00 hrs, dt= 0.01 hrs Link L: outfall Inflow Primary Hydrograph Time (hours) 3210Flow (cfs)18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=128,066 sf 16.74 cfs16.74 cfs