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HomeMy WebLinkAboutConsultant Review - 120 CAMPION ROAD 10/7/2013 Sullivan Engineering Group, LLC Civil Engineers&Land Development Consultants DRYWELL DESIGN CALCULATIONS 120 CAMPION ROAD, NORTH ANDOVER Due to the owner/applicant, Scott Sigman,proposing to construct a garage extension(convert an existing 2 car garage to a 3 car garage with living area above)to an existing single family dwelling in the Watershed Protection District, drainage mitigation measures are needed under the bylaw. The proposed project consists of an addition of a 3 car garage (presently there is a 2 car garage)with living space above, expansion of the existing paved driveway to access the new garage bay, slight site grading changes, and installation of a concrete drywell for drainage mitigation. The applicant is proposing to mitigate the increase in impervious cover associated with this project by installing a 500 gallon concrete drywell with 2 feet of crushed stone surrounding and 12"of crushed stone bedding to store/infiltrate a portion of the roof area runoff. As summarized on the design plan,the proposed site conditions for impervious cover will exceed existing conditions by 480 s.f.. The applicant is proposing to capture 685 s.f. of roof area to be piped via 4 inch pvc roof drains to the drywell. The drywell has been sized to store/infiltrate the 100 year storm event(HydroCAD calculations attached). Soil testing was conducted on-site on 10/4/13 to determine the soil percolation rate and estimated seasonal high groundwater table. A field percolation rate of 12 MPI was achieved and no groundwater/mottles were encountered to a depth of 96". The drywell is vertically located to maintain a minimum 2 foot separation to the high groundwater table per DEP Stormwater Standards. By providing the drywell for this project,there is an effective net reduction of impervious cover for this project of 205 s.£. HYDROCAD CALCULATIONS ON FOLLOWING PAGES r c,riN D. I 22 Mount Vernon Road Boxford,Massachusetts 01921 (978)352-7871-Phone 978352-7871 -Fax is Roof Area to Drywell NIZ 4 1 P 500 Gallon Drywell w/ 24" Stone Surrounding ......... ""'\........, Subcat Reach on Link Drainage Diagram for 120 Campion Road,NA Prepared by Sullivan Engineering Group, LLC 10/7/2013 - HydroCADO 7.00 s/n 001433 ©1986-2003 Applied Microcomputer Systems 120 Campion Road, NA Type ///24-hr 2 yr Rainfall=3.10" Prepared by Sullivan Engineering Group, LLC Page 2 HydroCADO 7.00 s/n 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Roof Area to Drywell Runoff Area=685 sf Runoff Depth=2.68" Tc=6.0 min CN=98 Runoff=0.05 cfs 153 cf Pond 1P: 500 Gallon Drywell w/24" Stone Surro Peak Elev=179.12' Storage=33 cf Inflow=0.05 cfs 153 cf Outflow=0.01 cfs 153 cf Total Runoff Area=685 sf Runoff Volume= 153 cf Average Runoff Depth= 2.68" 120 Campion Road, NA Type ///24-hr 2 yr Rainfall=3.10" Prepared by Sullivan Engineering Group, LLC Page 3 HydroCADO 7.00 s/n 001433 ©1 986-2003 Applied Microcomputer Systems 10/7/2013 Subcatchment IS: Roof Area to Drywell Runoff = 0.05 cfs @ 12.09 hrs, Volume= 153 cf, Depth= 2.68" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description 685 98 Roof Area to Drywell Tc Length Slope Velocity Capacity Description —(min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, From Roof Subcatchment IS: Roof Area to Drywell Hydrograph 0.05—: 0.048_ 0.05 cfs 0.046' 0.044_: Type III 24-hr 2 yr 0.042� 0.04= Rainfall=3.1 0" 0.038: 0.036= Runoff Area=686 sf 0.034- 0.032_ 0.03z� Runoff Volume=153 d 0.028_ 3 0.026—. Runoff Depth=2.68" 0.024—' LL 0.022-; 0.02' Tc=6.0 min 0.018z 0.016-1- CN=98 0.014-- 0.012_ 0.01— 0.008- 0.006 0.004—' 0.002 0 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 120 Campion Road, NA Type ///24-hr 2 yr Rainfall=3.10" Prepared by Sullivan Engineering Group, LLC Page 4 HydroCAD®7.00 s/n 001433 © 1986=2003 Applied Microcomputer Systems 10/7/2013 Pond 1 P: 500 Gallon Drywell w/ 24" Stone Surrounding Field Percolation Rate of Soil = 12 MPI [82] Warning: Early inflow requires earlier time span Inflow Area = 685 sf, Inflow Depth = 2.68" for 2 yr event Inflow = 0.05 cfs @ 12.09 hrs, Volume= 153 cf Outflow = 0.01 cfs @ 11.80 hrs, Volume= 153 cf, Atten= 75%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.80 hrs, Volume= 153 cf Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 179.12' @ 12.46 hrs Surf.Area= 100 sf Storage= 33 cf Plug-Flow detention time= 16.0 min calculated for 152 cf(100% of inflow) Center-of-Mass det. time= 15.4 min ( 754.3-738.9) # Invert Avail.Storage Storage Description 1 178.50' 133 cf 10.00'W x 10.00'L x 4.00'H Prismatoid 400 cf Overall-67 cf Embedded = 333 cf x 40.0% Voids 2 178.50' 67 cf 5.33'D x 3.00'H Vertical Cone/Cylinder Inside#1 200 cf Total Available Storage # Routing Invert Outlet Devices 1 Discarded 0.00' 0.006944 fpm Exfiltration over entire Surface area Discarded OutFlow Max=0.01 cfs @ 11.80 hrs HW=178.54' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.01 cfs) 120 Campion Road, NA Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Sullivan Engineering Group, LLC Page 5 HydroCADO 7.00 sln 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Pond 1 P: 500 Gallon Drywell w/24" Stone Surrounding Hydro r ph InflOW 0.05- [0,05 crs] Discarded Inflow Area=685 sf 0.045- 0.04= Peak 79.12' 0.035"0.035 Storage=33_cf_ N 0.03- n - 3 0.025- o LL 0.02- 0.015- - 0.01 cfs 0.01..: 0.005 0- 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 120 Campion Road, NA Type ///24-hr 10 yr Rainfall=4.80" Prepared by Sullivan Engineering Group, LLC Page 6 HydroCAD®7 00 s/n 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Roof Area to Drywell Runoff Area=685 sf Runoff Depth=4.24" Tc=6.0 min CN=98 Runoff=0.07 cfs 242 cf Pond 1P: 500 Gallon Drywell w/24" Stone Surro Peak Elev=179.81' Storage=70 cf Inflow=0.07 cfs 242 cf Outflow=0.01 cfs 242 cf Total Runoff Area = 685 sf Runoff Volume =242 cf Average Runoff Depth = 4.24" Road, NA Type 11124-hr 10 yr Rainfall=4.80° 12 0 Campion p Page 7 Prepared by Sullivan Engineering Group, LLC 10/7/2013 H droCADC�7.00 s/n 001433 © 1986-2003 A plied Microcom uter S stems Subcatchment IS: Roof Area to Drywell Runoff = 0.07 cfs @ 12.09 hrs, Volume= 242 cf, Depth= 4.24° Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.80 Areas CN Descri tion 685 98 Roof Area to Drywell Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec) (cfs) Direct Entry, From Roof 6.0 Subcatchment IS: Roof Area to Drywell Hydro r ph Runoff 0.08- ` 0.075: Type 11124-hr 1.0 yr 0.07': 0.065 Rainfall-4.80" 0.06 Runoff Area--686 sf 0.055 0.05_ Runoff Volume=242 d 0.045: Runoff Depth-4.24" 0.04° cc M 0.035. I T C=6.0 min 0.03= CN=98 0.025 0.02= 0.015_ 0.01- 0.005° 0 8 g 10 11 12 13 14 15 16 17 18 19 ZO 5 6 7 Time (hours) 120 Campion Road, NA Type 111 24-hr 10 yr Rainfall=4.80" Page 8 Prepared by Sullivan Engineering Group, LLC 10/7/2013 H droCADO 7.00 s/n 001433 © 1986-2003 A lied Microcom uter S stems Pond 1 P: 500 Gallon Drywell w/ 24" Stone Surrounding Field Percolation Rate of Soil = 12 MPI [82] Warning: Early inflow requires earlier time span Inflow Area = 685 sf, Inflow Depth = 4.24 for 10 yr event Inflow = 0.07 cfs @ 12.09 hrs, Volume= „ 242 cf Outflow = 0.01 cfs @ 11.70 hrs, Volume= 242 cf, Atten= 84%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.70 hrs, Volume= 242 cf Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 179.81' @ 12.56 hrs Surf.Area= 100 sf Storage= 70 cf Plug-Flow detention time= 37.1 min calculated for 241 cf(100% of inflow) Center-of-Mass det. time= 36.4 min (771.8-735.4) ## Invert Avail.Stora a Stora le Descri tion 1 178.50' 133 cf 10.00'W x 10.00'L x 4.00'H Prismatoid 400 cf Overall -67 cf Embedded = 333 cf x 40.0% Voids 2 178.50' 67 cf 5.33'D x 3.00'H Vertical Cone/C tinder Inside#1 200 cf Total Available Storage # Routing ,. Invert Outlet Devices 1 Discarded 0.00' 0.006944 fpm Exfiltration over entire Surface area Discarded OutFlow Max=0.01 cfs @ 11.70 hrs HW=178.55' (Free Discharge) t--1=Exfiltration (Exfiltration Controls 0.01 cfs) 120 Campion Road, NA Type /II 24-hr 10 yr Rainfall=4.80" Prepared by Sullivan Engineering Group, LLC Page 9 HydroCAD®7 00 s/n 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Pond 1 P: 500 Gallon Drywell wl 24" Stone Surrounding yror h Inflow 0.08: o.o7 crs Discarded 0.075 _ Inflow Area--685 sf 0.07 0.065- Peak E1ev=179.81' 0.06' } r 0.055= Storage=7® Cf 0.05 w 0.045] a 0.04 o W 0.035, 0.03-:: 0.025 0.02- 0.015: 0.01 cts 0.01 0.005= 0 A"; I I I ' I I 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 120 Campion Road, NA Type /1124-hr 100 yr Rainfall=6.40" Prepared by Sullivan Engineering Group, LLC Page 10 HydroCADO 7.00 s/n 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Roof Area to Drywell Runoff Area=685 sf Runoff Depth=5.69" Tc=6.0 min CN=98 Runoff=0.10 cfs 325 cf Pond 1P: 500 Gallon Drywell w/24" Stone Surro Peak Elev=180.51' Storage=107 cf Inflow=0.10 cfs 325 cf Outflow=0.01 cfs 325 cf Total Runoff Area= 685 sf Runoff Volume= 325 cf Average Runoff Depth = 5.69" 120 Campion Road, NA Type H/24-hr 100 yr Rainfal1=640" Prepared by Sullivan Engineering Group, LLC Page 11 HydroCADO 7.00 s/n 001433 @ 1986-2003 Applied Microcomputer Systems 10/7/2013 Subcatchment IS: Roof Area to Drywell Runoff = 0.10 cfs @ 12.09 hrs, Volume= 325 cf, Depth= 5.69" Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.40" Area (sf) CN Description 685 98 Roof Area to Drywell Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfS) 6.0 Direct Entry, From Roof Subcatchment IS: Roof Area to Drywell Hydro graph 0.105- Runoff 0.1 0.10 05 0.095-: 0,09 Type III 24-hr 1100 yr 0.085 Rainfall-6.40" 0.08-: 0.075 Runoff Ar1385 sf 0.07-: —0.065 Runoff Volume=325 ,cf .4 0.06= 0.055- 0.05 Runoff Depth=5.69" U.0.045- Tc=6.0 min 0.04: 0.035�- 0.03. 0.025-.: 0.02=: 0.015-. 0.01-: Room 0.005- 0- 5 6 7 8 10 11. . . .12 13. . . .14 115 16 . . .17 1'8' 19 20 Time (hours) 120 Campion Road, NA Type H/24-hr 100 yr Rainfall=6.40" Prepared by Sullivan Engineering Group, LLC Page 12 HydroCAD®7.00 s/n 001433 © 1986-2003 Applied Microcomputer Systems 10/7/2013 Pond 1 P: 500 Gallon Drywell w/ 24" Stone Surrounding Field Percolation Rate of Soil = 12 MPI [82] Warning: Early inflow requires earlier time span Inflow Area = 685 sf, Inflow Depth = 5.69" for 100 yr event Inflow = 0.10 cfs @ 12.09 hrs, Volume= 325 cf Outflow = 0.01 cfs @ 11.60 hrs, Volume= 325 cf, Atten= 88%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.60 hrs, Volume= 325 cf Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 180.51' @ 12.67 hrs Surf.Area= 100 sf Storage= 107 cf Plug-Flow detention time=62.6 min calculated for 324 cf(100% of inflow) Center-of-Mass det. time= 61.9 min (795.7- 733.9) # Invert Avail.Storage Storage Description 1 178.50' 133 cf 10.00'W x 10.00'L x 4.00'H Prismatoid 400 cf Overall - 67 cf Embedded = 333 cf x 40.0%Voids 2 178.50' 67 cf 5.33'D x 3.00'H Vertical Cone/Cylinder Inside#1 200 cf Total Available Storage # Routing Invert Outlet Devices 1 Discarded 0.00' 0.006944 fpm Exfiltration over entire Surface area Discarded OutFlow Max=0.01 cfs @ 11.60 hrs HW=178.54' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.01 cfs) 120 Campion Road, NA Type 11124-hr 100 yr Rainfall=6.40" Prepared by Sullivan Engineering Group, LLC Page 13 HydroCAD®7.00 s/n 001433 O 1986-2003 Applied Microcomputer Systems 10/7/2013 Pond 1P: 500 Gallon Drywell w/ 24" Stone Surrounding Hydro r ph ., _ Inflow {._. -;7;_� ®Discarded 0.105 c [via-;14 cs p1: 0.095 Inflow Area=685 sf 0.085. Peak Elev=180.51 ' 0.08= 0.075, storage=107 cf 0.07 0.065 0.06-. - "0.055 0 0.05 LL 0.045' 0.04 0.035 0.03 0.025 0.02' 0.015= 0.01 cfs v 0.01 0.005 0- 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours)