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2021.10.20 Glendale Road Cluster Development - Stormwater Management LetterBerkshireDesignGroup 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com October 19, 2021 Doug McDonald Northampton DPW 210 Main Street Northampton, MA 01060 RE:Glendale Road Cluster Development Stormwater Management Permit – Specific Permit Condition No. 4 Doug, The purpose of this letter is to address a condition of approval included as part of a Stormwater Management Permit issued for Waggin’ Trails Dog Park & Cluster Development in October 2017. Specific Permit Condition No. 4 requires a detailed set of plans and stormwater analysis for the final design of the 3-house cluster development (the “project”), located at the front of the property along Glendale Road. The project location is shown on attached Figure 1. A detailed set of plans are attached in the Glendale Road Cluster Development Building Permit Set. A detailed analysis of the final design follows. Existing Conditions An Existing Site Conditions plan for the project property is shown on Figure 2. The existing hydrology of the site is shown on Figure 4. For consistency, the drainage areas have retained their labels from the original Stormwater Management Report. Area E4 includes portions of the residential lots north and east of the site that run onto the site; runoff from this area discharges directly to Area E3. Area E3 includes the undisturbed portion of the site north of the existing gravel entry road. All runoff from these two drainage areas collects and infiltrates in the shallow low point within Area E3. Proposed Conditions The Proposed Site Plan for the project is shown on Figure 3. The project maintains the original proposal of reducing the size of the shallow low point within Area E3 and using it as an infiltration basin. The proposed hydrology of the site is shown on Figure 5. The limits for Areas P3 and P4 are identical to Areas E3 and E4. There are no changes between Area E4 and P4. Area P3 has an updated allocation of surface conditions, as well as the smaller infiltration basin, compared to Area E3. There are two local low points that are sized to act as sediment forebays for 0.1” of runoff from the pavement of the cluster development. A HydroCAD report comparing the existing and proposed hydrology is attached to this letter. Stormwater Standards Compliance The project will continue to meet the Massachusetts Stormwater Standards, as listed below: Standard 1: Stormwater Conveyance No outlets are present on the existing site, and the proposed site continues to retain and infiltrate all runoff. Standard 2: Peak Discharge The project will maintain the peak discharge rates and volumes as existing conditions. ‘Table 1: Peak Discharge Comparison’ shows the peak flow and total volume of runoff to the control point (Infiltration Basin) for the existing and proposed conditions. October 19, 2021 Glendale Road Cluster Development Stormwater Management Permit – Specific Permit Condition No. 4 Page 2 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 1: Peak Discharge Comparison 2-YR Storm (3.0")10-YR Storm (4.5")100-YR Storm (6.4") Condition Peak Flow (cfs) Total Volume (ac-ft) Peak Flow (cfs) Total Volume (ac-ft) Peak Flow (cfs) Total Volume (ac-ft) Existing 0.0 0.000 0.0 0.000 0.0 0.000 Proposed 0.0 0.000 0.0 0.000 0.0 0.000 Standard 3: Groundwater Recharge The project provides more than the required groundwater recharge volume, as shown in the calculations below: Required Recharge Volume Proposed Impervious Area = 19,380 sf Target Depth Factor (HSG A Soils) = 0.6” Required Recharge Volume = (19,380 sf) x (0.6”) x (1’/12”) = 969 cf Capture Area Adjustment All impervious area within the project site is routed to the infiltration basin which is the sole groundwater recharge device. Therefore, no capture area adjustment is necessary. Provided Recharge Volume Infiltration Basin Recharge Volume = 5,718 cf Recharge Systems Drawdown Time Soil evaluations have determined that the infiltration basin is located in sand. The Rawls infiltration rate for sand is 8.27 inches per hour. 8.27𝑖𝑛 ℎ𝑟× 72ℎ𝑟=592𝑖𝑛=49𝑓𝑡 The infiltration basin is far less than 49 ft deep, therefore it will drawdown in less than 72 hours. Standard 4: Total Suspended Solids (TSS) Removal The proposed site conditions is estimated to remove 85% of total suspended solids (TSS) of the post- construction site layout. The project will achieve this removal rate through use of sediment forebays and sheet flowing over vegetated areas, prior to collecting in the infiltration basin in Area P3. A TSS Removal Worksheet is attached. The project will also provide the requisite Water Quality Volume, as shown in the following calculations: October 19, 2021 Glendale Road Cluster Development Stormwater Management Permit – Specific Permit Condition No. 4 Page 3 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Infiltration Basin (Area P3) Impervious Area routed to Infiltration Basin = 19,380 sf Water Quality Depth = 1” Required Water Quality Volume = (19,380 sf) x (1’/12”) x (1”) = 1,615 cf Provided Water Quality Volume = 5,718 cf > 1,615 cf OK Standard 5: Land uses with Higher Potential Pollutant Load (LUHPPL) The project is not expected to yield high potential pollutant loads. Standard 6: Critical Areas The project is located within a Zone II drinking water protection area. Adequate water quality volume has been provided in accordance with Standard 4. All runoff is infiltrated to groundwater, therefore there is no direct discharge within the protected area. Standard 7: Redevelopment Project The project is not a redevelopment project. Standard 8: Erosion & Sediment Control Erosion and sediment controls have been incorporated into the project design to prevent erosion, control sediments, and stabilize exposed soils during construction and land disturbance. A full Stormwater Pollution Prevention Plan will be developed by the contractor prior to any disturbance of the site. Standard 9: Operation & Maintenance Plan An updated Operation and Maintenance (O&M) Plan, specific to the devices within this project, is attached. Standard 10: Prohibition of Illicit Discharges An Illicit Discharge Compliance Statement is included with this letter. Conclusion The project design meets Specific Permit Condition No. 4. The stormwater management system permitted in October 2017 will continue to operate as designed. Please do not hesitate to contact Liam at (413) 582-7000 or liam@berkshiredesign.com if you have any questions about the information contained in this letter. Sincerely, Berkshire Design Group, Inc. Chris Chamberland, PE PROJECT LOCATIONChecked By:Drawn By:RevisionsScale:Date:Sheet NumberThis drawing is not intended nor shall it be used forconstruction purposes unless the signed professional seal of aregistered landscape architect, civil engineer or land surveyoremployed by The Berkshire Design Group, Inc. is affixed above.Do not scale drawing for quantity take-offs or construction. Usewritten dimensions only. If dimensions are incomplete, contactThe Berkshire Design Group Inc. for clarification.Copyright The Berkshire Design Group, Inc.This drawing and all of its contents are the express property ofThe Berkshire Design Group, Inc., and shall not be copied orused in any way without the written consent of The BerkshireDesign Group, Inc.cGLENDALE ROADCLUSTER DEVELOPMENTNORTHAMPTON, MASSACHUSETTSWeb: http://www.berkshiredesign.comEmail: bdg@berkshiredesign.com (413) 582-70004 Allen Place, Northampton, Massachusetts 01060FAX (413) 582-7005Landscape ArchitectureCivil EngineeringPlanningBerkshireGroupDesignLand SurveyingOCTOBER 18, 2021LMCCFIG11"=200'LOCATION PLAN0400200100600 267268269270271272273274 27 5 27 6 27 7 2 7 8 27 7 27 8 27 9 2 8 0 281 282 283 284 282283284285286287288289290291292293294295295280 281 278 279 Gravel D r i v e Trail Bituminous Concrete 2 7 9 280 281282284285286287288 289290291292293293.68 293.55 293.35 293.21 276 277278294 294295293 281.09 Gate Post Gate Post Gate Woods Woods Woods OHWOHW"Sharp Turns" Sign Bituminous ConcreteApproxim a t e E d g e O f P a v e m e n t Glendale RoadPublic Right Of Way ~ 3 Rod Width277278279 278283 285 286 287 284 290 288 289 282 281 280 2 7 9 279 280 291 2802 8 1 28 2 28 3 2 8 4 2 8 5 28 6 28 7 28 8 2892 9 0 2902912922932942952962962 9 5 Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contactThe 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 orused in any way without the written consent of The Berkshire Design Group, Inc. c GLENDALE ROAD CLUSTER DEVELOPMENT NORTHAMPTON, MASSACHUSETTS 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 OCTOBER 18, 2021 LM CC FIG21"=40' EXISTING SITE CONDITIONS 0 804020 120 26826927027127227327 4 27 5 27 6 27 7 2 7 8 27 6 27 7 27 8 27 9 2 8 0 281 282 283 284 282283284285286287288289290291292293294295295280 281 278 279 Gravel D r i v e Trail Bituminous Concrete 2 7 9 280 281282284285286287288 28929029 1 292293293.68 293.55 293.35 293.21 276 277278294 294295293 292294 281.09 Gate Post Gate Post Gate Woods Woods Woods OHWOHWOHWOHWOHW"Sharp Turns" Sign UP 26 Bituminous ConcreteApproxim a t e E d g e O f P a v e m e n t Glendale Road277278279 278283 285 286 287 284 290 288 289 282 281 280 2 79 279 280 291 2802 8 1 28 2 28 3 2 8 4 2 8 5 28 6 28 7 28 8 28 9 2 9 0 2902912922932942952962962 95295 29 4 293 292 291 29 0 289288287286285284GarageGarageFront PorchBRKit.LivingRoomDeckGarage Front DeckFrontBituminous Concrete Gate Post Gate Post Gate OHWOHWOHWOHWOHWUP 26 Shed Woods Woods Woods Shed 22.0'11.0 'Edge Of Propos e d Driveway Edge Of Pr o posed Drive way 295 н295 н295296296296 296н296 294293292291290289288293294295;292Ϳ;291Ϳ;290Ϳ296289288287286285284283282290291290291292293294289288286 287285 282 283 283 283282281282283282281280283 282 281280 284283282281280280279>P 27 9 .5279LOW POINT FOR WATER QUALITY 237 Glendale Road Assessor ID 49-060 Cluster Lot #1 241 Glendale Road Assessor ID 49-061 Cluster Lot #2 245 Glendale Road Assessor ID 49-062 Cluster Lot #3 LOW POINT FOR WATER QUALITY MAINTAIN EXISTING LOW POINT FOR INFILTRATION Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contactThe 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 orused in any way without the written consent of The Berkshire Design Group, Inc. c GLENDALE ROAD CLUSTER DEVELOPMENT NORTHAMPTON, MASSACHUSETTS 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 OCTOBER 18, 2021 LM CC FIG31"=40' PROPOSED SITE PLAN 0 1404020 120 32"Twin 258.85 258.79 258.41 258.51 258.70 261.36 272.73 272.74 300.59 300.54 301.56 301.33 313.39 303.40 286.74 310.03 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 29 6 29729 8 29930 0 301261 262 263 264 265 25 9 260 261 262263264 26526626726826927027127227 3 274 27 5 27 6 27 7 27 8 27 3 274 27 5 27 6 27 7 27 8 279 28 0 281 282 283 284 269270271272 273275276282283284285286287288289290291292293294295295280 281 278 279 301 300 Gravel D r i v e Trail BituminousConcrete 27 9 280 281282284285286287288 289290291 292293293.68 293.55 293.35 293.21 274 275 276 277278273273272.57 272.57 301.83 294 294295293 292291292293 294 267 281.09 X X Gate Post Gate Post Gate Gravel Pit Soil Pile Soil Pile Soil Pile Soil Pile OHWOHWOHWOHW"Sharp Turns" Sign UP 26 UP 27 X X Bituminous ConcreteTrees/Posts With Wire Meander This Line 1/4" Iron Rod Up 2.5'In 1/2" Iron Pipe Up 0.5'(Held) 1 1/2" Iron PipeUp 0.3' (Held) At Base1 1/2" Iron PipeUp 0.5'5'+/- Off Corner 1" Iron PipeFlush (HeldFor Direction) Approxima t e E d g e O f P a v e m e n t 1" Iron Pipe 49.648 Acres 2162662.10 Sq. Feet ±100' WetlandBuffer ZoneTP-1 TP-3 TP-4 TP-5 TP-7 TP-8 TP-9 292293 289 290 288277278279278283 285 286 287 284 290 288 289 282 281 280 27 9 279 280 291 28028 1 28 2 28 3 28 4 28 5 286 287 288 28 9 29 0 290291292293294295296 29629 5 DRAINAGE AREA E3 TOTAL: 119,280 SF IMPERVIOUS: 4,380 GRAVEL: 1,400 SF WOODS: 113,500 SF DRAINAGE AREA E4 TOTAL: 150,627 SF IMPERVIOUS: 2,200 SF GRASS: 73,427 SF WOODS: 75,000 SF Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contactThe 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 orused in any way without the written consent of The Berkshire Design Group, Inc. c GLENDALE ROAD CLUSTER DEVELOPMENT NORTHAMPTON, MASSACHUSETTS 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 OCTOBER 18, 2021 LM CC FIG41"=70' EXISTING HYDROLOGY 0 1407035 210 32"Twin 258.85 258.79 258.41 258.51 258.70 261.37 261.36 272.73 272.74 300.59 300.54 301.56 301.33 313.39 307.42 303.40 286.74 310.03 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 29 6 29729 8 29930 0 301295 261 262 263 264 265 266 267 268 269 25 9 260 261 262263264 26526626726826927027127227 3 274 27 5 27 6 27 7 27 8 27 2 27 3 274 27 5 27 6 27 7 27 8 279 28 0 281 282 283 284 269 270271272 273274275276 282283284285286287288289290291292293294295295280 281 278 279301300 Gravel D r i v e Trail BituminousConcrete 27 9 280 281282284285286287288 289290 291 292293293.68 293.55 293.35 293.21 274 275 276 277278273273274 272.57 272.57 301.83 294 294295293 293 292291292293 294 267 281.09 X X Gate Post GatePost Gate Gravel Pit Soil Pile Soil Pile Soil Pile Soil PileSoil Pile Concrete Woods Woods Woods Woods Woods Woods Tree LineTree Line OHWOHWOHWOHW"Sharp Turns" Sign UP 26 UP 27 X X Bituminous ConcreteApproxima t e E d g e O f P a v e m e n t 100' Wetland Buffer Zone 100' WetlandBuffer ZoneTP-1 TP-2 TP-3 TP-4 TP-5 TP-7 TP-8 TP-9 292293 289 290 2 8 8 28 728 6277278279278283 285 286 287 284 290 288 289 282 281 280 27 9 279 280 291 28028 1 28 2 28 3 28 4 28 5 286 287 288 28 9 29 0 290291292293294295296 29629 5 E E W W W W WVWWWWWW WE 29 5 294 293 292 291 29 0 289288287286285284E GarageGarageFront PorchBRKit.LivingRoomDeckGarage Front DeckFrontGravel D r i v e Bituminous Concrete GatePost GatePost Gate Concrete Woods Woods Tree Line OHWOHWOHWOHWUP 26 UP 27 Shed 395511 Sq. Ft. 9.08 Ac. Woods Woods Woods Woods Shed 22. 0'11.0' Edge O f P r o p os ed D riv ew ay Edge O f P ro po se d D ri v e wa y 295 н295 н295296296296 296WV н296 E EE294293292291290289288293294295;292Ϳ;291Ϳ;290Ϳ296289288287286285284283282290291290291292293294289288286 287285 282 283 283 283282281282283282281280283282281280 284283282281280 WWWW280 279LP 27 9 . 5279 WV WV DRAINAGE AREA P4 TOTAL: 150,627 SF IMPERVIOUS: 2,200 SF GRASS: 73,427 SF WOODS: 75,000 SF DRAINAGE AREA P3 TOTAL: 119,280 SF IMPERVIOUS: 17,980 SF GRAVEL: 1,400 SF GRASS: 33,200 SF WOODS: 66,700 SF Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contactThe 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 orused in any way without the written consent of The Berkshire Design Group, Inc. c GLENDALE ROAD CLUSTER DEVELOPMENT NORTHAMPTON, MASSACHUSETTS 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 OCTOBER 18, 2021 LM CC FIG51"=70' PROPOSED HYDROLOGY 0 1407035 210 E3 Existing Building Lot E4 Existing Offsite Northeast P3 Proposed Building Lot P4 Proposed Offsite Northeast ECP Existing Control Point PCP Proposed Control Point EP2 Existing Pond 2 (Depression in Building Lot) PP2 Modified Existing Pond 2 (Depression in Building Lot) Routing Diagram for Glendale RD - HydrologyPrepared by Berkshire Design Group, Printed 10/18/2021 HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 2HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Rainfall Events Listing (selected events) Event# Event Name Storm Type Curve Mode Duration (hours) B/B Depth (inches) AMC 1 2-Year Type III 24-hr Default 24.00 1 3.00 2 2 10-Year Type III 24-hr Default 24.00 1 4.50 2 3 100-Year Type III 24-hr Default 24.00 1 6.40 2 Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 3HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 4.133 39 >75% Grass cover, Good, HSG A (E4, P3, P4) 0.064 96 Gravel surface, HSG A (E3, P3) 0.614 98 Paved parking, HSG A (E3, E4, P3, P4) 7.580 30 Woods, Good, HSG A (E3, E4, P3, P4) 12.392 37 TOTAL AREA Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 4HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area (acres) Soil Group Subcatchment Numbers 12.392 HSG A E3, E4, P3, P4 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 12.392 TOTAL AREA Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 5HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Ground Covers (all nodes) HSG-A (acres) HSG-B (acres) HSG-C (acres) HSG-D (acres) Other (acres) Total (acres) Ground Cover Subcatchment Numbers 4.133 0.000 0.000 0.000 0.000 4.133 >75% Grass cover, Good E4, P3, P4 0.064 0.000 0.000 0.000 0.000 0.064 Gravel surface E3, P3 0.614 0.000 0.000 0.000 0.000 0.614 Paved parking E3, E4, P3, P4 7.580 0.000 0.000 0.000 0.000 7.580 Woods, Good E3, E4, P3, P4 12.392 0.000 0.000 0.000 0.000 12.392 TOTAL AREA Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 6HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=119,280 sf 3.67% Impervious Runoff Depth=0.00"Subcatchment E3: Existing Building Lot Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 Runoff=0.00 cfs 0.000 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth=0.00"Subcatchment E4: Existing Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.00 cfs 0.000 af Runoff Area=119,280 sf 15.07% Impervious Runoff Depth>0.02"Subcatchment P3: Proposed Building Lot Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 Runoff=0.01 cfs 0.003 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth=0.00"Subcatchment P4: Proposed Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afReach ECP: Existing Control Point Outflow=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afReach PCP: Proposed Control Point Outflow=0.00 cfs 0.000 af Peak Elev=277.00' Storage=0 cf Inflow=0.00 cfs 0.000 afPond EP2: Existing Pond 2 (Depression in Discarded=0.00 cfs 0.000 af Primary=0.00 cfs 0.000 af Outflow=0.00 cfs 0.000 af Peak Elev=277.00' Storage=1 cf Inflow=0.01 cfs 0.003 afPond PP2: Modified Existing Pond 2 Discarded=0.01 cfs 0.003 af Primary=0.00 cfs 0.000 af Outflow=0.01 cfs 0.003 af Total Runoff Area = 12.392 ac Runoff Volume = 0.003 af Average Runoff Depth = 0.00" 95.04% Pervious = 11.778 ac 4.96% Impervious = 0.614 ac Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 7HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E3: Existing Building Lot Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 4,380 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 113,500 30 Woods, Good, HSG A 119,280 33 Weighted Average 114,900 96.33% Pervious Area 4,380 3.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.4 400 0.0861 0.36 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment E3: Existing Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=119,280 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 8HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E4: Existing Offsite Northeast Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment E4: Existing Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=150,627 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 9HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed Building Lot Runoff = 0.01 cfs @ 21.19 hrs, Volume= 0.003 af, Depth> 0.02" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 17,980 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 33,200 39 >75% Grass cover, Good, HSG A 66,700 30 Woods, Good, HSG A 119,280 44 Weighted Average 101,300 84.93% Pervious Area 17,980 15.07% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 400 0.0861 0.49 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment P3: Proposed Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=119,280 sf Runoff Volume=0.003 af Runoff Depth>0.02" Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 0.01 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 10HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Proposed Offsite Northeast Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 2-Year Rainfall=3.00" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment P4: Proposed Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 2-Year Rainfall=3.00" Runoff Area=150,627 sf Runoff Volume=0.000 af Runoff Depth=0.00" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 11HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach ECP: Existing Control Point Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth = 0.00" for 2-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach ECP: Existing Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 12HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach PCP: Proposed Control Point Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth = 0.00" for 2-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach PCP: Proposed Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 13HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth = 0.00" for 2-Year event 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 Discarded = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.00' @ 0.00 hrs Surf.Area= 2,127 sf Storage= 0 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no inflow) Volume Invert Avail.Storage Storage Description #1 277.00' 23,301 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) 277.00 2,127 200.0 0 0 2,127 278.00 14,284 470.1 7,308 7,308 16,534 279.00 17,765 524.0 15,993 23,301 20,827 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 1=Exfiltration (Passes 0.00 cfs of 0.41 cfs potential flow) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 14HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac Peak Elev=277.00' Storage=0 cf 0.00 cfs0.00 cfs0.00 cfs0.00 cfs Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 15HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth > 0.01" for 2-Year event Inflow = 0.01 cfs @ 21.19 hrs, Volume= 0.003 af Outflow = 0.01 cfs @ 21.23 hrs, Volume= 0.003 af, Atten= 0%, Lag= 2.5 min Discarded = 0.01 cfs @ 21.23 hrs, Volume= 0.003 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.00' @ 21.23 hrs Surf.Area= 2,128 sf Storage= 1 cf Plug-Flow detention time= 1.7 min calculated for 0.003 af (100% of inflow) Center-of-Mass det. time= 0.9 min ( 1,195.1 - 1,194.2 ) Volume Invert Avail.Storage Storage Description #1 277.00' 16,698 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) 277.00 2,127 200.0 0 0 2,127 278.00 10,339 418.8 5,718 5,718 12,906 279.00 11,632 442.9 10,979 16,698 14,614 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.41 cfs @ 21.23 hrs HW=277.00' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.41 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 2-Year Rainfall=3.00"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 16HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)0.006 0.005 0.005 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.000 0 Inflow Area=6.196 ac Peak Elev=277.00' Storage=1 cf 0.01 cfs0.01 cfs0.01 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 17HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=119,280 sf 3.67% Impervious Runoff Depth>0.01"Subcatchment E3: Existing Building Lot Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 Runoff=0.00 cfs 0.002 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth>0.03"Subcatchment E4: Existing Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.01 cfs 0.009 af Runoff Area=119,280 sf 15.07% Impervious Runoff Depth>0.26"Subcatchment P3: Proposed Building Lot Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 Runoff=0.20 cfs 0.059 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth>0.03"Subcatchment P4: Proposed Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.01 cfs 0.009 af Inflow=0.00 cfs 0.000 afReach ECP: Existing Control Point Outflow=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afReach PCP: Proposed Control Point Outflow=0.00 cfs 0.000 af Peak Elev=277.00' Storage=2 cf Inflow=0.02 cfs 0.011 afPond EP2: Existing Pond 2 (Depression in Discarded=0.02 cfs 0.011 af Primary=0.00 cfs 0.000 af Outflow=0.02 cfs 0.011 af Peak Elev=277.01' Storage=20 cf Inflow=0.20 cfs 0.068 afPond PP2: Modified Existing Pond 2 Discarded=0.20 cfs 0.068 af Primary=0.00 cfs 0.000 af Outflow=0.20 cfs 0.068 af Total Runoff Area = 12.392 ac Runoff Volume = 0.079 af Average Runoff Depth = 0.08" 95.04% Pervious = 11.778 ac 4.96% Impervious = 0.614 ac Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 18HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E3: Existing Building Lot Runoff = 0.00 cfs @ 23.00 hrs, Volume= 0.002 af, Depth> 0.01" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.50" Area (sf) CN Description 4,380 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 113,500 30 Woods, Good, HSG A 119,280 33 Weighted Average 114,900 96.33% Pervious Area 4,380 3.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.4 400 0.0861 0.36 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment E3: Existing Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.005 0.005 0.005 0.004 0.004 0.004 0.004 0.004 0.003 0.003 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0 Type III 24-hr 10-Year Rainfall=4.50" Runoff Area=119,280 sf Runoff Volume=0.002 af Runoff Depth>0.01" Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 0.00 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 19HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E4: Existing Offsite Northeast Runoff = 0.01 cfs @ 17.31 hrs, Volume= 0.009 af, Depth> 0.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.50" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment E4: Existing Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 10-Year Rainfall=4.50" Runoff Area=150,627 sf Runoff Volume=0.009 af Runoff Depth>0.03" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.01 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 20HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed Building Lot Runoff = 0.20 cfs @ 12.51 hrs, Volume= 0.059 af, Depth> 0.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.50" Area (sf) CN Description 17,980 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 33,200 39 >75% Grass cover, Good, HSG A 66,700 30 Woods, Good, HSG A 119,280 44 Weighted Average 101,300 84.93% Pervious Area 17,980 15.07% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 400 0.0861 0.49 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment P3: Proposed Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type III 24-hr 10-Year Rainfall=4.50" Runoff Area=119,280 sf Runoff Volume=0.059 af Runoff Depth>0.26" Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 0.20 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 21HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Proposed Offsite Northeast Runoff = 0.01 cfs @ 17.31 hrs, Volume= 0.009 af, Depth> 0.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 10-Year Rainfall=4.50" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment P4: Proposed Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Type III 24-hr 10-Year Rainfall=4.50" Runoff Area=150,627 sf Runoff Volume=0.009 af Runoff Depth>0.03" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.01 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 22HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach ECP: Existing Control Point Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth = 0.00" for 10-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach ECP: Existing Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 23HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach PCP: Proposed Control Point Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth = 0.00" for 10-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach PCP: Proposed Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 24HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth > 0.02" for 10-Year event Inflow = 0.02 cfs @ 21.57 hrs, Volume= 0.011 af Outflow = 0.02 cfs @ 21.58 hrs, Volume= 0.011 af, Atten= 0%, Lag= 0.5 min Discarded = 0.02 cfs @ 21.58 hrs, Volume= 0.011 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.00' @ 21.58 hrs Surf.Area= 2,132 sf Storage= 2 cf Plug-Flow detention time= 1.7 min calculated for 0.011 af (100% of inflow) Center-of-Mass det. time= 0.9 min ( 1,189.1 - 1,188.2 ) Volume Invert Avail.Storage Storage Description #1 277.00' 23,301 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) 277.00 2,127 200.0 0 0 2,127 278.00 14,284 470.1 7,308 7,308 16,534 279.00 17,765 524.0 15,993 23,301 20,827 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.41 cfs @ 21.58 hrs HW=277.00' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.41 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 25HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)0.018 0.017 0.016 0.015 0.014 0.013 0.012 0.011 0.01 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 0 Inflow Area=6.196 ac Peak Elev=277.00' Storage=2 cf 0.02 cfs0.02 cfs0.02 cfs 0.00 cfs Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 26HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth > 0.13" for 10-Year event Inflow = 0.20 cfs @ 12.51 hrs, Volume= 0.068 af Outflow = 0.20 cfs @ 12.54 hrs, Volume= 0.068 af, Atten= 1%, Lag= 1.7 min Discarded = 0.20 cfs @ 12.54 hrs, Volume= 0.068 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.01' @ 12.54 hrs Surf.Area= 2,176 sf Storage= 20 cf Plug-Flow detention time= 1.7 min calculated for 0.068 af (100% of inflow) Center-of-Mass det. time= 1.1 min ( 1,008.7 - 1,007.5 ) Volume Invert Avail.Storage Storage Description #1 277.00' 16,698 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) 277.00 2,127 200.0 0 0 2,127 278.00 10,339 418.8 5,718 5,718 12,906 279.00 11,632 442.9 10,979 16,698 14,614 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.42 cfs @ 12.54 hrs HW=277.01' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.42 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 10-Year Rainfall=4.50"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 27HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=6.196 ac Peak Elev=277.01' Storage=20 cf 0.20 cfs0.20 cfs0.20 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 28HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Time span=0.00-24.00 hrs, dt=0.01 hrs, 2401 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Runoff Area=119,280 sf 3.67% Impervious Runoff Depth>0.24"Subcatchment E3: Existing Building Lot Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 Runoff=0.09 cfs 0.054 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth>0.34"Subcatchment E4: Existing Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.28 cfs 0.097 af Runoff Area=119,280 sf 15.07% Impervious Runoff Depth>0.89"Subcatchment P3: Proposed Building Lot Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 Runoff=1.43 cfs 0.203 af Runoff Area=150,627 sf 1.46% Impervious Runoff Depth>0.34"Subcatchment P4: Proposed Offsite Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 Runoff=0.28 cfs 0.097 af Inflow=0.00 cfs 0.000 afReach ECP: Existing Control Point Outflow=0.00 cfs 0.000 af Inflow=0.00 cfs 0.000 afReach PCP: Proposed Control Point Outflow=0.00 cfs 0.000 af Peak Elev=277.02' Storage=36 cf Inflow=0.36 cfs 0.151 afPond EP2: Existing Pond 2 (Depression in Discarded=0.36 cfs 0.151 af Primary=0.00 cfs 0.000 af Outflow=0.36 cfs 0.151 af Peak Elev=277.39' Storage=1,268 cf Inflow=1.46 cfs 0.300 afPond PP2: Modified Existing Pond 2 Discarded=0.88 cfs 0.300 af Primary=0.00 cfs 0.000 af Outflow=0.88 cfs 0.300 af Total Runoff Area = 12.392 ac Runoff Volume = 0.451 af Average Runoff Depth = 0.44" 95.04% Pervious = 11.778 ac 4.96% Impervious = 0.614 ac Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 29HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E3: Existing Building Lot Runoff = 0.09 cfs @ 13.02 hrs, Volume= 0.054 af, Depth> 0.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=6.40" Area (sf) CN Description 4,380 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 113,500 30 Woods, Good, HSG A 119,280 33 Weighted Average 114,900 96.33% Pervious Area 4,380 3.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 18.4 400 0.0861 0.36 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment E3: Existing Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Type III 24-hr 100-Year Rainfall=6.40" Runoff Area=119,280 sf Runoff Volume=0.054 af Runoff Depth>0.24" Flow Length=400' Slope=0.0861 '/' Tc=18.4 min CN=33 0.09 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 30HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment E4: Existing Offsite Northeast Runoff = 0.28 cfs @ 12.58 hrs, Volume= 0.097 af, Depth> 0.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=6.40" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment E4: Existing Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 100-Year Rainfall=6.40" Runoff Area=150,627 sf Runoff Volume=0.097 af Runoff Depth>0.34" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.28 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 31HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P3: Proposed Building Lot Runoff = 1.43 cfs @ 12.26 hrs, Volume= 0.203 af, Depth> 0.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=6.40" Area (sf) CN Description 17,980 98 Paved parking, HSG A 1,400 96 Gravel surface, HSG A 33,200 39 >75% Grass cover, Good, HSG A 66,700 30 Woods, Good, HSG A 119,280 44 Weighted Average 101,300 84.93% Pervious Area 17,980 15.07% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 13.5 400 0.0861 0.49 Lag/CN Method, Contour Length= 10,265' Interval= 1' Subcatchment P3: Proposed Building Lot Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Type III 24-hr 100-Year Rainfall=6.40" Runoff Area=119,280 sf Runoff Volume=0.203 af Runoff Depth>0.89" Flow Length=400' Slope=0.0861 '/' Tc=13.5 min CN=44 1.43 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 32HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Proposed Offsite Northeast Runoff = 0.28 cfs @ 12.58 hrs, Volume= 0.097 af, Depth> 0.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Type III 24-hr 100-Year Rainfall=6.40" Area (sf) CN Description 2,200 98 Paved parking, HSG A 73,427 39 >75% Grass cover, Good, HSG A 75,000 30 Woods, Good, HSG A 150,627 35 Weighted Average 148,427 98.54% Pervious Area 2,200 1.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.6 400 0.0836 0.38 Lag/CN Method, Contour Length= 12,589' Interval= 1' Subcatchment P4: Proposed Offsite Northeast Runoff Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type III 24-hr 100-Year Rainfall=6.40" Runoff Area=150,627 sf Runoff Volume=0.097 af Runoff Depth>0.34" Flow Length=400' Slope=0.0836 '/' Tc=17.6 min CN=35 0.28 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 33HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach ECP: Existing Control Point Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth = 0.00" for 100-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach ECP: Existing Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 34HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Reach PCP: Proposed Control Point Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth = 0.00" for 100-Year event 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 Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Reach PCP: Proposed Control Point InflowOutflow Hydrograph Time (hours) 2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac 0.00 cfs0.00 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 35HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 2.44% Impervious, Inflow Depth > 0.29" for 100-Year event Inflow = 0.36 cfs @ 12.62 hrs, Volume= 0.151 af Outflow = 0.36 cfs @ 12.65 hrs, Volume= 0.151 af, Atten= 1%, Lag= 2.1 min Discarded = 0.36 cfs @ 12.65 hrs, Volume= 0.151 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.02' @ 12.65 hrs Surf.Area= 2,240 sf Storage= 36 cf Plug-Flow detention time= 1.7 min calculated for 0.151 af (100% of inflow) Center-of-Mass det. time= 1.2 min ( 1,004.1 - 1,002.9 ) Volume Invert Avail.Storage Storage Description #1 277.00' 23,301 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) 277.00 2,127 200.0 0 0 2,127 278.00 14,284 470.1 7,308 7,308 16,534 279.00 17,765 524.0 15,993 23,301 20,827 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.43 cfs @ 12.65 hrs HW=277.02' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.43 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 36HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond EP2: Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=6.196 ac Peak Elev=277.02' Storage=36 cf 0.36 cfs0.36 cfs0.36 cfs 0.00 cfs Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 37HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Summary for Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Area = 6.196 ac, 7.48% Impervious, Inflow Depth > 0.58" for 100-Year event Inflow = 1.46 cfs @ 12.38 hrs, Volume= 0.300 af Outflow = 0.88 cfs @ 12.71 hrs, Volume= 0.300 af, Atten= 40%, Lag= 20.4 min Discarded = 0.88 cfs @ 12.71 hrs, Volume= 0.300 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.01 hrs Peak Elev= 277.39' @ 12.71 hrs Surf.Area= 4,574 sf Storage= 1,268 cf Plug-Flow detention time= 9.3 min calculated for 0.300 af (100% of inflow) Center-of-Mass det. time= 8.9 min ( 951.2 - 942.3 ) Volume Invert Avail.Storage Storage Description #1 277.00' 16,698 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) 277.00 2,127 200.0 0 0 2,127 278.00 10,339 418.8 5,718 5,718 12,906 279.00 11,632 442.9 10,979 16,698 14,614 Device Routing Invert Outlet Devices #1 Discarded 277.00'8.270 in/hr Exfiltration over Surface area #2 Primary 278.00'10.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Discarded OutFlow Max=0.88 cfs @ 12.71 hrs HW=277.39' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.88 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=277.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Type III 24-hr 100-Year Rainfall=6.40"Glendale RD - Hydrology Printed 10/18/2021Prepared by Berkshire Design Group Page 38HydroCAD® 10.10-5a s/n 11721 © 2020 HydroCAD Software Solutions LLC Pond PP2: Modified Existing Pond 2 (Depression in Building Lot) Inflow Outflow Discarded Primary Hydrograph Time (hours)2423222120191817161514131211109876543210Flow (cfs)1 0 Inflow Area=6.196 ac Peak Elev=277.39' Storage=1,268 cf 1.46 cfs 0.88 cfs0.88 cfs 0.00 cfs V Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed 1. From MassDEP Stormwater Handbook Vol. 1 Mass. Dept. of Environmental Protection INSTRUCTIONS:Version 1, Automated: Mar. 4, 2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected, TSS Removal and other Columns are automatically completed. Location:Drainage Areas P3 & P4 B C D E F TSS Removal Starting TSS Amount Remaining BMP1 Rate1 Load*Removed (C*D)Load (D-E)TSS RemovalCalculation WorksheetSediment Forebay 0.25 1.00 0.25 0.75 Infiltration Basin 0.80 0.75 0.60 0.15 0.00 0.15 0.00 0.15 0.00 0.15 0.00 0.15 0.00 0.15 0.00 0.15 Total TSS Removal =85% Separate Form Needs to be Completed for Each Outlet or BMP Train Project:Glendale Rd Cluster Develop. Prepared By:Berkshire Design Grp.*Equals remaining load from previous BMP (E) Date:10/18/2021 which enters the BMP Glendale Road Cluster Development October 19, 2021 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc.Page 1 Stormwater Management System Operation & Maintenance Plan During Construction The Contractor shall be responsible for inspection and maintenance during construction. At all times, siltation fabric fencing, stakes and straw bales/wattles, sufficient to construct a sedimentation control barrier a minimum of 50 feet long, shall be stockpiled on the site in order to repair established barriers which may be damaged or breached. An inspection of all erosion control and stormwater management systems shall be conducted by the Contractor at least once a week and during all rain storms until the completion of construction. In case of any noted breach or failure, the Contractor shall immediately make appropriate repairs to any erosion control system and notify the engineer of any problems involving stormwater management systems. A rain storm shall be defined as any of the following: A storm in which rain is predicted to last for twelve consecutive hours or more. A storm for which a flash flood watch or warning is issued. A single storm predicted to have a cumulative rainfall of greater than one-half inch. A storm not meeting the previous three thresholds but which would mark a third consecutive day of measurable rainfall. The Contractor shall also inspect the erosion control and stormwater management systems at times of significant increase in surface water runoff due to rapid thawing when the risk of failure of erosion control measures is elevated. In such instances as remedial action is necessary, the Contractor shall repair any and all significant deficiencies in erosion control systems within two days. The Northampton Department of Public Works shall be notified of any significant failure of stormwater management systems or erosion and sediment control measures, and shall be notified of any release of pollutants to a water body (stream, brook, pond, etc.). The Contractor shall remove the sediment from behind the fence of the sedimentation control barrier when the accumulated sediment has reached one-half of the original installed height of the barrier. This project requires a NPDES General Permit for Stormwater Discharges from Constriction Activities. Contractor and Owner are responsible for finalizing a Stormwater Pollution Prevention Plan (SWPPP) and filing for the NDPES permit prior to the start of construction. All clearing, grading, drainage, construction, and development shall be conducted in strict accordance with the SWPPP. Glendale Road Cluster Development October 19, 2021 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc.Page 2 Post-Construction Stormwater Management System Owner: MS Homes LLC (413) 244-0336 Party Responsible for Operation & Maintenance: MS Homes LLC (413) 244-0336 Inspection & Maintenance Schedule: 1)Sediment Forebays The sediment forebays shall be inspected as needed, multiple times in the first few months after construction, and twice per year thereafter. Sediment or debris shall be cleaned out as needed. Note and repair any erosion or low spots. 2)Infiltration Basin The infiltration basin shall be inspected at least four times per year for sediment accumulation and signs of damage or erosion. Sediment shall be removed any time it has accumulated more than ½”. At a minimum, sediment shall be removed annually. Failure of the system to drain (ponding 48 hours after the end of the storm) shall result in inspection and cleaning. Sediments shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. Inspections shall identify any damage or signs of erosion within basin/swales, which shall be repaired immediately. It is recommended that sediment removal be performed after the completion of the spring snow melt. 3)Street Sweeping Regular street sweeping will prevent sediment from reaching the stormwater treatment chamber. This will extend the life of stormwater treatment elements, and will reduce the effort and expense of cleaning those element. Street sweeping is not required under this plan; however, sweeping twice per year (including after the spring snow melt) is recommended.