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HomeMy WebLinkAboutWPO201700005 Plan - As-built Engineering Approval 2020-02-03STORMWATER MANAGEMENT REPORT Timberland Park Apartments APPROVED by the Albemarle County Community Development Department Date 4/7/2020 File WP0201700005 AND ASSOCIATES INC REFLECTING TOMORROW 1561 Commerce Road, Suite 401 Verona, VA 24482 540-248-3220 Prepared by: Kent O'Donohue, Jr. Balzer & Associates Project No: 34160034 January 4, 2017 Revised March 14, 2017 As -Built February 3rd, 2020 Table of Contents: INTRODUCTION.......................................................................................................................... 1 HYDROLOGIC & HYDRAULIC ANALYSIS............................................................................. 1 ExistingConditions................................................................................................................. 1 Pre-Development.................................................................................................................... 1 Table 1: Pre -developed Storm Rates.............................................................................. 1 Post-Development................................................................................................................... 2 Table 2: Post -developed Storm Rates before Detention ................................................ 2 Stormwater Quantity Management......................................................................................... 2 Table 3: Pre- to Post -Developed Storm Rates after Detention ...................................... 3 StormwaterQuality................................................................................................................. 3 AdequateChannel................................................................................................................... 3 Stormwater Conveyance Calculations.................................................................................... 3 OutletProtection..................................................................................................................... 4 Stormwater Maintenance........................................................................................................ 4 Attachments: Pre development Gak-Watiefts, Page:5 Page 112 Revised Post Detention Calculations for POA 1 & 2 Page 7 Revised Storm Conveyance Calculations Page 58 Revised Bioretention Calculations Page 60 For all other calculations refer to approved SWM Report dated 03-14-2017 STORMWATER MANAGEMENT REPORT Timberland Park Apartments INTRODUCTION This project consists of the construction of four apartment buildings and a clubhouse. The subject parcel exists at 7.757 acres and is proposed after ROW dedication at 7.635 acres. The property is located in Albemarle County, Virginia along Old Lynchburg Road. A total of 5.5 acres will be disturbed during construction of the apartments and entrance into the property. The existing site is characterized as vacant, dense woodland. Existing slopes range from 5% to 50%. Stormwater compliance for this project is in accordance with current state regulations for a "New -development" project. (County code 17-302 and State Code 9VAC25-870-62 thru 9VAC25-870-66). This report documents the storm water design recommended by Balzer & Associates, Inc. After analysis of the site under pre and post -development conditions, a determination of the appropriate stormwater management design was made. HYDROLOGIC & HYDRAULIC ANALYSIS Existing Conditions Currently the site topography consists of a hill with a ridge running through the middle conveying site drainage to a concrete ditch north of the property and a culvert running underneath Old Lynchburg Rd. to the south of the property. Existing slopes range from 5% to 50%. Existing ground cover consists of dense trees. Pre -Development Existing topography breaks the site in half along a ridge. The northern half of the site flows north to point of analysis, POA 1 (concrete ditch north of the property). The southern half of the site conveys water to point of analysis, POA 2 (culvert running underneath Old Lynchburg Rd.). Ground cover consists of dense woods. The enclosed Drainage Map (Sheet DA-1) illustrates the drainage areas for the site and the path of the pre -developed time of concentration. For POA 2, the 1-year flowrate is a combination of DA-B (on -site improvements) and DA-B 1 (off -site area flowing to the POA). For energy balance considerations, only the on -site area is subjected to the improvement factor. Based upon a hydrologic analysis of the site (see attached Pre -Development Calculations), the pre -development run- off rates for the identified drainage areas are as follows: Table 1: Pre -developed Storm Rates Storm Event Flowrate (cfs) DA-A POA 1 DA-B POA 2 Q1 = 0.13 0.94 Q 10 = 1.98 4.86 TOC = 12.4 min. 13.4 min. Stormwater Management Report Timberland Park Apartments These values were achieved using existing site contours, averaging slopes across the time of concentration lengths, and using appropriate Curve Numbers. The analysis of the pre -development run- off rates for the drainage areas was performed using Hydro -CAD® v. 10 computer software. All calculations were performed in general accordance with the TR-55 Method outlined in the Virginia Stormwater Management Handbook. Post -Development For post -development analysis, we have determined the amount of additional impervious area within the drainage areas for the currently proposed site development. Based upon a hydrologic analysis of the site (see attached Post -Development Calculations), the post -development run-off rates are as follows: Table 2: Post -developed Storm Rates before Detention Storm Event Flowrate (cfs) DA-A POA 1 DA-B POA 2 Q1 = 4.35 1.48 Q 10 = 14.70 4.79 TOC = 5.0 min. 10.0 min. Due to the increase in drainage area for POA 1 and the reduction in drainage area for POA 2, the post developed flowrates before detention for POA 1 drastically increase while the flowrates for POA 2 increase, but not as significantly. Both areas will be analyzed further to meet Energy Balance and Flood Protection requirements below. Stormwater Quantity Management Two Level 2 Bioretention basins with 0.5' of surface storage are proposed for stormwater quantity management for POA 1. These basins will treat runoff from Post -developed DA-Al and DA- A2, as depicted in Post -Development Drainage Map DA-2, and leave DA-A3 undetained. For POA 2, two detention pipes are proposed to treat runoff from Post -developed DA-B 1 (offsite area) and DA-B3 while leaving DA-B2 undetained. An analysis of the proposed basins and detention pipes were performed using Hydro -CAD® v. 10 computer software. The following table illustrates the reduction in run-off rates when comparing pre -development flowrates and required Energy Balance flowrates to detained post -development flowrates. Stormwater Management Report Timberland Park Apartments Table 3: Pre- to Post -Developed Storm Rates after Detention POA 1 cfs) POA 2 (cfs Storm Event Pre Post Energy Balance Max Pre Post 0.76 Energy Balance Max Q 1 = 0.13 0.01 0.01 0.94 0-.74 0.81 Q10 = 1.98 4-. 4.86 4.42 - 1.74 By providing bio-retention and detention, the post -development stormwater flowrates are below pre -developed flowrates when comparing 1-year pre -developed Energy Balance Runoff to the 1-year post -developed and pre -developed 10-year to the post -developed 10-year stormwater flowrates. Stormwater Quality For water quality analysis, the project limits of disturbance of 5.48 acres was used to calculate phosphorus loading rates. The site is treated as a New Development. The proposed development will result in total impervious area of 2.39 acres (44%). Based on the proposed development, a total Phosphorous load reduction of 4.34 lbs P/yr is needed. To treat the stormwater quality, the proposed development includes the construction of two level 2 Bioretention Basins. Based on the existing and proposed land use of the area draining to the BMP, the basin obtains a total removal rate of 5.03 lbs P/yr, exceeding the required P removal. We have provided calculations for the water quality measures proposed for the site development (see attached Water Quality Calculations). Adequate Channel Since the Energy Balance method was used and the 10-yr post development discharge rates into the existing concrete channel (POA 1) and culvert under Old Lynchburg Rd. (POA 2) are lower than the pre developed condition the existing storm conveyance system is adequate for DA-A & B. The existing culvert under Old Lynchburg Road. (POA 2) was also analyzed for a 10-yr storm with a tailwater condition to show the impacts pre to post of the site's development. The peak 10-yr storm elevation of the existing conditions is 413.57' and already spills over Old Lynchburg and runs across a superelevation to the other side of the road where the existing culvert discharges. The post conditions peak 10-yr storm elevation also spills over Old Lynchburg Road but is slightly lower at 413.51'. The tailwater condition was also applied to our detention pipe system. The 10-yr storm fills the detention system; however, does not escape any upstream inlets in the site (see attached HGL-10yr calculations). Outlet Protection Conveyance systems discharging into th pretreatment cells which were sized adequately Stormwater Management Handbook 2nd Edition. Stormwater Management Report Timberland Park Apartments e two bio-retention cells required proposed rip -rap for the bioretention inflow based on the Virginia An outlet protection was sized to accommodate the 10-year storm event for the flow leaving the detention pipe system at the end of Storm Str #13 and Storm Str #39, see attached Inlet Drainage Area Map DA-3 and Outlet Protection calculation. Stormwater Maintenance Maintenance of stormwater pipes within the subject property will be the responsibility of the property owner. Maintenance of the Bioretention Basin will be the responsibility of the property owner. POST POA 1 1-YR Al -1 YR POST DA-Al A2-1YR VPOST DA-A2 A2-P Al-P BIO 2 B10 1 A-R POST POA 1 (30" CMP) Subcat Reach on Link POST DA-A3 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 2 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentA1-lYR: POST DA-Al Runoff Area=1.850 ac 0.00% Impervious Runoff Depth=0.74" Tc=5.0 min CN=70 Runoff=1.59 cfs 0.114 of SubcatchmentA2-1YR: POST DA-A2 Runoff Area=2.320 ac 0.00% Impervious Runoff Depth=0.94" Tc=5.0 min CN=74 Runoff=2.74 cfs 0.182 of SubcatchmentA3-S: POST DA-A3 Runoff Area=0.040 ac 0.00% Impervious Runoff Depth=0.38" Tc=5.0 min CN=61 Runoff=0.01 cfs 0.001 of Reach A-R: POST POA 1 (30" CMP) Inflow=0.01 cfs 0.001 of Outflow=0.01 cfs 0.001 of Pond Al-P: BIO 1 Peak Elev=433.92' Storage=4,980 cf Inflow=1.59 cfs 0.114 of Outflow=0.00 cfs 0.000 of Pond A2-P: BIO 2 Peak Elev=424.61' Storage=7,917 cf Inflow=2.74 cfs 0.182 of Outflow=0.00 cfs 0.000 of Total Runoff Area = 4.210 ac Runoff Volume = 0.297 of Average Runoff Depth = 0.85" 100.00% Pervious = 4.210 ac 0.00% Impervious = 0.000 ac 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment Al-1YR: POST DA-Al Runoff = 1.59 cfs @ 12.04 hrs, Volume= 0.114 af, Depth= 0.74" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 1.850 70 CN FROM RR SPREADSHEET 1.850 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment Al-1YR: POST DA-Al Hydrograph 1.59 cfs Illlll�lli IIIIIIIIII IIIIIIIIII I_I — Runoff l ITirrible�land Par'k ��-hr S1 1 �yr IIII i l l Rainfall= 31.05" Runoff Area=1.850 ac IIII Runoff Volume=0A 4at —LILD! Ru"ffbepth=0_714' Tc=5,01rr�ir� 2 33 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 734 35 36 37 38 39 41 Time (hours) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment A2-1YR: POST DA-A2 Runoff = 2.74 cfs @ 12.03 hrs, Volume= 0.182 af, Depth= 0.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 2.320 74 CN FROM RR SPREADSHEET 2.320 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment A2-1YR: POST DA-A2 Hydrograph ++I� 2.74 cfs ITim eland Par'k ��-hr S1 1�yr i l l Rainfall= 31.05" l l l Runoff Airea=2.320 ac Runoff Volume=0.182 of Runoiff Dlepth=OI.94" Tc=50lrr�i� II'11'�II"IIIIIIIIIIIIIII I Il�lliill IIIIIIIIIIIIII 1 II'Illllllllllllllllllllll 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment A3-S: POST DA-A3 Runoff = 0.01 cfs @ 12.05 hrs, Volume= 0.001 af, Depth= 0.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.040 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment A3-S: POST DA-A3 Hydrograph 0.011 0.01 0.01 cfs H H H HH �- 0.009 inn erl nil P�r 24 lir S1 f- yr� 0.008�IH-I HI IH H HI H IH HI H Irt-IRainfall=30'r 0.00 H H 1 T HI H HHHH1HI�tT� — �o Qg-a 0.007 0.006 14 1 H H 14 1 H H H 1 unV1 1 H kul rio&f ID�Oth-43t'F 0.006 H --� — -H -f I -H -� -- �- H -I- �� 0.005 — — �m�� 0.004 -H Irt I HI IH HI H IH t I HI H Irt H I HI IH 1 — 0.003 H H IHI H IHI1IHI H 1-1I11H IH III 0.003 0.002 0.002 H HI H I H I H H H I H 1 H_l 41 0.001 0.001 F H H f+ I -HH I S 0.000 0 1 2 3 4 5 6 7 8 9 1011 1213 14 15 16 17 18 19 20 2122 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 6 Summary for Reach A-R: POST POA 1 (30" CMP) Inflow Area = 4.210 ac, 0.00% Impervious, Inflow Depth = 0.00" for 1-yr event Inflow = 0.01 cfs @ 12.05 hrs, Volume= 0.001 of Outflow = 0.01 cfs @ 12.05 hrs, Volume= 0.001 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Reach A-R: POST POA 1 (30" CMP) Hydrograph 0.011 - 0.01 0.01 cfs 001- 0.009 0.009- 0.008 - 0.008 1 11 ID El 0.007= 0.007- y 0.006. 4 14 14-1 1- 0.006 _ 0 0.005 FL 0.0050.004 - I - - 0.004 0.003 _ I� I L I� 1-I 0.003- — 0.002 - 4 14 I�— I J 0.002 f 0.001= — — — 0.001 14—I H I 0.000 _ Inflow Area=4.210 ac �I-H H It -I H I_+I -i LI Li I -II I _LI Li I_ I DII I -II I II II ILI I4I+Id--I H I4I 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow Outflow 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 7 Summary for Pond Al-P: BIO 1 Inflow Area = 1.850 ac, 0.00% Impervious, Inflow Depth = 0.74" for 1-yr event Inflow = 1.59 cfs @ 12.04 hrs, Volume= 0.114 of Outflow = 0.00 cfs @ 1.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Primary = 0.00 cfs @ 1.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 433.92' @ 24.29 hrs Surf.Area= 3,591 sf Storage= 4,980 cf Plug -Flow detention time= (not calculated: initial storage exceeds outflow) Center -of -Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 427.36' 15,237 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 427.36 1,900 0.0 0 0 430.69 1,900 40.0 2,531 2,531 432.19 2,500 25.0 825 3,356 433.69 2,500 25.0 938 4,293 434.00 4,000 100.0 1,008 5,301 435.00 5,200 100.0 4,600 9,901 435.92 6,400 100.0 5,336 15,237 Device Routing Invert Outlet Devices #1 Primary 434.79' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.05 0.05 0.55 Width (feet) 0.29 0.29 8.00 8.00 Primary OutFlow Max=0.00 cfs @ 1.00 hrs HW=427.36' (Free Discharge) L1=Custom Weir/Orifice ( Controls 0.00 cfs) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 8 Pond Al -P: BIO 1 Hydrograph 1.59 cfs —Inflow — Primary in,fio'w r5ad Leak ev 1413131.��, ISltora ��eI 4,69 6'cfl I� _I U II1 I LI LI 1 LL II IIIIIIIIIIII IIII illli IIIIIIIIIIII I� II�I�II�IIIIIIIIII IIIIIIIIII Ililllll Illllllllllllllll �I�IIIIIIII IIIIIIIIIIIIIIIIIIIIIIIII 0.00 cfs 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3132 33 34 Time (hours) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 9 Summary for Pond A2-P: BIO 2 Inflow Area = 2.320 ac, 0.00% Impervious, Inflow Depth = 0.94" for 1-yr event Inflow = 2.74 cfs @ 12.03 hrs, Volume= 0.182 of Outflow = 0.00 cfs @ 1.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min Primary = 0.00 cfs @ 1.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 424.61' @ 24.29 hrs Surf.Area= 4,901 sf Storage= 7,917 cf Plug -Flow detention time= (not calculated: initial storage exceeds outflow) Center -of -Mass det. time= (not calculated: no outflow) Volume Invert Avail.Storage Storage Description #1 418.76' 18,868 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 418.76 3,100 0.0 0 0 421.09 3,100 40.0 2,889 2,889 422.59 3,800 25.0 1,294 4,183 424.09 3,800 25.0 1,425 5,608 424.50 4,800 100.0 1,763 7,371 425.00 5,250 100.0 2,513 9,883 426.00 6,300 100.0 5,775 15,658 426.49 6,800 100.0 3,210 18,868 Device Routing Invert Outlet Devices #1 Primary 424.92' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.08 1.08 1.57 Width (feet) 0.50 0.50 16.00 16.00 Primary OutFlow Max=0.00 cfs @ 1.00 hrs HW=418.76' (Free Discharge) L1=Custom Weir/Orifice ( Controls 0.00 cfs) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 10 Pond A2-P: BIO 2 Hydrograph 3 I -F- I T I 2.74 cfs _ Inflow Primary in, f io, w rea-2. �6 ac Leak �jev 1412141.6�'i,I �IIIIIIIII Illlll� I III 2 S' orate�--T 1 t �hf N Ililllllli IIIIIIITIIIIIIIIII U. IIIIIIIIIIIIIIIIII Ililllilli Ilillllll l 'Illlllllllll 1 IIIIIIIIII LL IIIIIlIIIIIIIII 0.00 cfs 0- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) POST POA 1 10& 100-YR Al-10YR POST DA-A P ST DA-A2 AA2-P' Al-P BIO 2 BIO 1 �A3-S A-R POST DA-A3 POST POA 1 (30" CMP) S4 Reach on Link 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 2 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentA1-10YR: POST DA-Al Runoff Area=1.850 ac 0.00% Impervious Runoff Depth=2.74" Tc=5.0 min CN=73 Runoff=6.01 cfs 0.423 of SubcatchmentA2-10YR: POST DA-A2 Runoff Area=2.320 ac 0.00% Impervious Runoff Depth=3.12" Tc=5.0 min CN=77 Runoff=8.61 cfs 0.602 of SubcatchmentA3-S: POST DA-A3 Runoff Area=0.040 ac 0.00% Impervious Runoff Depth=1.73" Tc=5.0 min CN=61 Runoff=0.08 cfs 0.006 of Reach A-R: POST POA 1 (30" CMP) Inflow=1.74 cfs 0.609 of Outflow=1.74 cfs 0.609 of Pond Al-P: BIO 1 Peak Elev=434.93' Storage=9,515 cf Inflow=6.01 cfs 0.423 of Outflow=0.73 cfs 0.219 of Pond A2-P: BIO 2 Peak Elev=425.64' Storage=13,444 cf Inflow=8.61 cfs 0.602 of Outflow=1.00 cfs 0.384 of Total Runoff Area = 4.210 ac Runoff Volume = 1.031 of Average Runoff Depth = 2.94" 100.00% Pervious = 4.210 ac 0.00% Impervious = 0.000 ac 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment Al-10YR: POST DA-Al Runoff = 6.01 cfs @ 12.03 hrs, Volume= 0.423 af, Depth= 2.74" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 1.850 73 CN FROM RR SPREADSHEET 1.850 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment Al-10YR: POST DA-Al Hydrograph — Runoff Tim6e�lan1d Pak 21 hr S1 0-yr III I I I I P2$iofoii�5.58" ac re Z Volu��-0.4�3 of +-�urr oflf-Depth�7j41'--- Tc=5.0 min _t It fil h lrt lrtl fil _rl l- Irt ltI ti 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 Time (hours) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment A2-10YR: POST DA-A2 Runoff = 8.61 cfs @ 12.03 hrs, Volume= 0.602 af, Depth= 3.12" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 2.320 77 CN FROM RR SPREADSHEET 2.320 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, N w 0 U. Subcatchment A2-10YR: POST DA-A2 Hydrograph 8.61 cfs - I l l Tlmli and Park 4-hr 1 10-yr IIIIII i I I i Rainfall''=5.58" Runoff Area=2.320 ac- IIIIIIII l Ill Ru%dff Voiumb4.662' of IIIIIIII I I Runoff Pops h�J.1121' IIIIIIII TIe 5.�j� 6�=71 IIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIII ITI 1 1 T 7 171 1 1 1 1 I7 1 IT I 7171 I7 1 1 1 F1 1 7 1TI T1 1T I I7 1T1 TI T I� ITI TI TI IT I7 1T1 � 771IItl1 71TTT1 If TTT7ITT 2 33 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 734 35 36 37 38 39 41 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment A3-S: POST DA-A3 Runoff = 0.08 cfs @ 12.03 hrs, Volume= 0.006 af, Depth= 1.73" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.040 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, 0.08-. 0.075 —I 0.07 0.065 0.06 0.055- 0.05 0.045- 0 0.04 LL 0.035 - 0.03 0.025- — 0.02 0.015 0.01 0.005 Subcatchment A3-S: POST DA-A3 Hydrograph I I I I I 0.08 cfs t l t-I 17 t t I I —F 4_1 w� II III H h 111 t-1 I I 11 t I t 1 I I t� I I 1-t �I4-1 14 IIIIIIII rtT I fit 1- IIII1II 1-1 fl Irt 4 -I I t-I I" I �_ 1 N 14 Timberland Park 24-hr S1 10-yr Rainfall=5.58" Runoff Area=0.040 ac Runoff Volume=0.006 of fi �I Runoff Depth=1.73" �Tc=5.0 min CN=61 TIMrilrtltlt_lNlII �_ I _�_I k_� 14 -I- I �__I 1-4 141 I I I I I I L I'�<_IIIIIII111Ld 11 11 11 1 12 13 14 1516 17 18 19 20 2122 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 6 Summary for Reach A-R: POST POA 1 (30" CMP) Inflow Area = 4.210 ac, 0.00% Impervious, Inflow Depth > 1.74" for 10-yr event Inflow = 1.74 cfs @ 12.69 hrs, Volume= 0.609 of Outflow = 1.74 cfs @ 12.69 hrs, Volume= 0.609 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Reach A-R: POST POA 1 (30" CMP) Hydrograph MH 1.74 cfs IIII HIM III�rlIn lowea=4.��O ac IIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIII' IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII 'Illllllllll IIIII IlIl II I IIIIIIIIIIIIIIII II II IIIIIIIIIIIII II IIIIIIIIIIIIIII IIIIIIII II II IIIIII IIIIIII IIII1I (IIIII II (IIIIIIIIIIIII IIIIIIIIIIIII 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 Time (hours) Inflow Outflow 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 7 Summary for Pond Al-P: BIO 1 Inflow Area = 1.850 ac, 0.00% Impervious, Inflow Depth = 2.74" for 10-yr event Inflow = 6.01 cfs @ 12.03 hrs, Volume= 0.423 of Outflow = 0.73 cfs @ 12.69 hrs, Volume= 0.219 af, Atten= 88%, Lag= 39.6 min Primary = 0.73 cfs @ 12.69 hrs, Volume= 0.219 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 434.93' @ 12.69 hrs Surf.Area= 5,110 sf Storage= 9,515 cf Plug -Flow detention time= 302.5 min calculated for 0.219 of (52% of inflow) Center -of -Mass det. time= 164.8 min ( 1,015.5 - 850.8 ) Volume Invert Avail.Storage Storage Description #1 427.36' 15,237 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 427.36 1,900 0.0 0 0 430.69 1,900 40.0 2,531 2,531 432.19 2,500 25.0 825 3,356 433.69 2,500 25.0 938 4,293 434.00 4,000 100.0 1,008 5,301 435.00 5,200 100.0 4,600 9,901 435.92 6,400 100.0 5,336 15,237 Device Routing Invert Outlet Devices #1 Primary 434.79' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.05 0.05 0.55 Width (feet) 0.29 0.29 8.00 8.00 Primary OutFlow Max=0.67 cfs @ 12.69 hrs HW=434.93' (Free Discharge) L1=Custom Weir/Orifice (Weir Controls 0.67 cfs @ 0.97 fps) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 8 Pond Al -P: BIO 1 Hydrograph 3 0 6.01 cfs Inhowl�► I I� Irt fi �I I- rea=1.�5� ac I�Ie-�akI_Iov 43-4 Sl itora�e ,1 1� d�1_ Irtlfil �I 3 1 0.73 cfs II'IIIII� I I �I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow — Primary 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 9 Summary for Pond A2-P: BIO 2 Inflow Area = 2.320 ac, 0.00% Impervious, Inflow Depth = 3.12" for 10-yr event Inflow = 8.61 cfs @ 12.03 hrs, Volume= 0.602 of Outflow = 1.00 cfs @ 12.69 hrs, Volume= 0.384 af, Atten= 88%, Lag= 39.9 min Primary = 1.00 cfs @ 12.69 hrs, Volume= 0.384 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 425.64' @ 12.69 hrs Surf.Area= 5,919 sf Storage= 13,444 cf Plug -Flow detention time= 296.7 min calculated for 0.384 of (64% of inflow) Center -of -Mass det. time= 174.5 min ( 1,013.6 - 839.0 ) Volume Invert Avail.Storage Storage Description #1 418.76' 18,868 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 418.76 3,100 0.0 0 0 421.09 3,100 40.0 2,889 2,889 422.59 3,800 25.0 1,294 4,183 424.09 3,800 25.0 1,425 5,608 424.50 4,800 100.0 1,763 7,371 425.00 5,250 100.0 2,513 9,883 426.00 6,300 100.0 5,775 15,658 426.49 6,800 100.0 3,210 18,868 Device Routing Invert Outlet Devices #1 Primary 424.92' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.08 1.08 1.57 Width (feet) 0.50 0.50 16.00 16.00 Primary OutFlow Max=1.00 cfs @ 12.69 hrs HW=425.64' (Free Discharge) L1=Custom Weir/Orifice (Weir Controls 1.00 cfs @ 2.77 fps) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 10 Pond A2-P: BIO 2 Hydrograph 3 0 U. 0.0 cis Anfio' 'l rea=2-320 ac IIIII tor; l ' ii,444-cf1 IIIII IIIIIiIIIIIIIIIITIIIIIIIIII IIil�II�I�Illilli�il� 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow — Primary 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here) Printed 2/3/2020 HvdroCAD®10.00-25 s/n 07714 ©2019 HvdroCAD Software Solutions LLC Page 11 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentA1-10YR: POST DA-Al Runoff Area=1.850 ac 0.00% Impervious Runoff Depth=5.85" Tc=5.0 min CN=73 Runoff=10.42 cfs 0.902 of SubcatchmentA2-10YR: POST DA-A2 Runoff Area=2.320 ac 0.00% Impervious Runoff Depth=6.35" Tc=5.0 min CN=77 Runoff=14.07 cfs 1.227 of SubcatchmentA3-S: POST DA-A3 Runoff Area=0.040 ac 0.00% Impervious Runoff Depth=4.35" Tc=5.0 min CN=61 Runoff=0.17 cfs 0.015 of Reach A-R: POST POA 1 (30" CMP) Inflow=18.91 cfs 1.722 of Outflow=18.91 cfs 1.722 of Pond Al-P: BIO 1 Peak EIev=435.30' Storage=11,506 cf Inflow=10.42 cfs 0.902 of Outflow=8.18 cfs 0.698 of Pond A2-P: BIO 2 Peak EIev=426.29' Storage=17,529 cf Inflow=14.07 cfs 1.227 of Outflow=10.61 cfs 1.009 of Total Runoff Area = 4.210 ac Runoff Volume = 2.144 of Average Runoff Depth = 6.11" 100.00% Pervious = 4.210 ac 0.00% Impervious = 0.000 ac 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment Al-10YR: POST DA-Al Runoff = 10.42 cfs @ 12.03 hrs, Volume= 0.902 af, Depth= 5.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 1.850 73 CN FROM RR SPREADSHEET 1.850 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, LL Subcatchment Al-10YR: POST DA-Al Hydrograph 10.42 cfs Timberland Parkl2"- rSS 100-yr Rainfall`=9.16" Runoff Area=1.850 ac Runoff Volume=0.'902 of I C Ft RUnoh75.85 Tc=5.0-m i1 73 I III III I�III�IIIIIII�IIIIIII�IIII ICI J_I lJ_ 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 726 27 28 29 30 31 32 33 34 35 377 38 39 41 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment A2-10YR: POST DA-A2 Runoff = 14.07 cfs @ 12.03 hrs, Volume= 1.227 af, Depth= 6.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 2.320 77 CN FROM RR SPREADSHEET 2.320 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, 1 1 1 1 1 1 w 0 LL Subcatchment A2-10YR: POST DA-A2 Hydrograph Tim�lb�rlanci Pa�kl2"hr' Sf1 100-yr I _ T 1 T I T I T I R$irjf611�=9.16" LL Ft����W7 �2.320 ac 0 1.227 aU IT1 171 TI IT T IT1 171 TI I= TTIT TI T TITT T T T1T III11111111111111111111111 14 11-1 T I TI -r IT I --I- 1 1-1 TI -I I T -I- TTITTIT TITITIITTIT 26 27 18 5 6 7 8 9 10 11 12 13 14 15 16 17 19 20 21 22 7377 28 29 30 31 32 33 34 35 377 38 39 41 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment A3-S: POST DA-A3 Runoff = 0.17 cfs @ 12.03 hrs, Volume= 0.015 af, Depth= 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 0.040 61 >75% Grass cover, Good, HSG B 0.040 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 u 0.1 0 0.09 LL 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Subcatchment A3-S: POST DA-A3 Hydrograph 4- 0. 1 cfs L I L Timt�et�nP�r 24i�` Sfi 1 fJO� y� 1 11 IT! I L L III I I 17 ITI L I III Rai0fa11=!�A6" _ 1 I-T I T I. L I 1-1 _T ITI _ IF-1 17 I L Runoff Area=0.040 ac L I uFno"ol�rnle=0.0�5 of _ f'� 1 I L I N I__- I t I t I tj Rom° 'I_4 351' Ic=5.0f-_m� — — — — — — — — i n I --I H I -I- I+ I +-I H I -I- I+ I-I-bN=61 I I -I- I I �- I I_I I -I- I -I- I �- I I -I I- -IT' I' I I _ILILI L ILI_LILI L L_ILILI 1-I L T 7 C ITI 71 17 MITI 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 Time (hours) — Runoff 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 15 Summary for Reach A-R: POST POA 1 (30" CMP) Inflow Area = 4.210 ac, 0.00% Impervious, Inflow Depth > 4.91" for 100-yr event Inflow = 18.91 cfs @ 12.08 hrs, Volume= 1.722 of Outflow = 18.91 cfs @ 12.08 hrs, Volume= 1.722 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Reach A-R: POST POA 1 (30" CMP) Hydrograph ;o T I_I 18.91 cfs - -M 1fin o1w Are = 1� � � - s '1 I' LI I11 I1 11 11 Z D lZ 1 -D I�III_I I I I—L -i II L 13 I 12 + 11 to 14 1 -- -- + 9 $—�i 1--k14-1HHI414--WHHI414_1 7 1+I4-1 H H IH W -H H H I41� 5 L L 4 H H 3 2 Ji —� -I fi t I H H t i t- 1 — 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) _ Inflow Outflow 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 16 Summary for Pond Al-P: BIO 1 Inflow Area = 1.850 ac, 0.00% Impervious, Inflow Depth = 5.85" for 100-yr event Inflow = 10.42 cfs @ 12.03 hrs, Volume= 0.902 of Outflow = 8.18 cfs @ 12.07 hrs, Volume= 0.698 af, Atten= 21 %, Lag= 2.8 min Primary = 8.18 cfs @ 12.07 hrs, Volume= 0.698 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 435.30' @ 12.07 hrs Surf.Area= 5,588 sf Storage= 11,506 cf Plug -Flow detention time= 173.5 min calculated for 0.698 of (77% of inflow) Center -of -Mass det. time= 74.2 min ( 905.8 - 831.6 ) Volume Invert Avail.Storage Storage Description #1 427.36' 15,237 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 427.36 1,900 0.0 0 0 430.69 1,900 40.0 2,531 2,531 432.19 2,500 25.0 825 3,356 433.69 2,500 25.0 938 4,293 434.00 4,000 100.0 1,008 5,301 435.00 5,200 100.0 4,600 9,901 435.92 6,400 100.0 5,336 15,237 Device Routing Invert Outlet Devices #1 Primary 434.79' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.05 0.05 0.55 Width (feet) 0.29 0.29 8.00 8.00 Primary OutFlow Max=8.14 cfs @ 12.07 hrs HW=435.30' (Free Discharge) L1=Custom Weir/Orifice (Weir Controls 8.14 cfs @ 2.22 fps) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 17 3 0 U. Pond Al -P: BIO 1 Hydrograph 10.42 cfs i_ T I _ T n� I TITT - I TI T T 8.18 cfs r iT I+ T T T FFMTI lliTFFIFHFII ow i4�ea= d ad e�=435�C% �IHv �¢ '��r��i� ��'ri`��1f MIMIIllllilllllllllllllllllll T 9 Time (hours) 31 323334 Inflow — Primary 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 18 Summary for Pond A2-P: BIO 2 Inflow Area = 2.320 ac, 0.00% Impervious, Inflow Depth = 6.35" for 100-yr event Inflow = 14.07 cfs @ 12.03 hrs, Volume= 1.227 of Outflow = 10.61 cfs @ 12.08 hrs, Volume= 1.009 af, Atten= 25%, Lag= 3.2 min Primary = 10.61 cfs @ 12.08 hrs, Volume= 1.009 of Routing by Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 426.29' @ 12.08 hrs Surf.Area= 6,596 sf Storage= 17,529 cf Plug -Flow detention time= 192.6 min calculated for 1.009 of (82% of inflow) Center -of -Mass det. time= 108.3 min ( 928.7 - 820.4 ) Volume Invert Avail.Storage Storage Description #1 418.76' 18,868 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Voids Inc.Store Cum.Store (feet) (sq-ft) (%) (cubic -feet) (cubic -feet) 418.76 3,100 0.0 0 0 421.09 3,100 40.0 2,889 2,889 422.59 3,800 25.0 1,294 4,183 424.09 3,800 25.0 1,425 5,608 424.50 4,800 100.0 1,763 7,371 425.00 5,250 100.0 2,513 9,883 426.00 6,300 100.0 5,775 15,658 426.49 6,800 100.0 3,210 18,868 Device Routing Invert Outlet Devices #1 Primary 424.92' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 1.08 1.08 1.57 Width (feet) 0.50 0.50 16.00 16.00 Primary OutFlow Max=10.56 cfs @ 12.08 hrs HW=426.29' (Free Discharge) L1=Custom Weir/Orifice (Weir Controls 10.56 cfs @ 2.04 fps) 2017-02-21 SWM POA 1 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 19 3 0 Pond A2-P: BIO 2 Hydrograph 15 — 1 14.07 cfs 14 t 1 fit 1 11 —/� 'n 13 — lnf w /'"'�1 eQ—t3tV -ac 12 Q U , 10.61 cfs -L F-1 7 I G V i 4 7 �0 7 71 71� tp�ag 171-1 f 9 � 14 -� 1 4-1 � �-I 1-4 1-- r�- -� -I-- �- 8 17I T 171 7 71 7 17 I T I7 1. 1 L I� III 1 7 6 14 1+1 -1 H H I� 14 1�1 �1 I I I4 ICI �I 1 4 IIIIIIIIII 3-1 1- t I -�-1 Ht1 1-1 H I I I� t1 2IL IILILI L.I-LILILI L ILIIILI L 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 M Time (hours) Inflow — Primary iW90"1987M f�r B 3-S B1-S P ST DA-B3 POST DA- B-P DET IPE O`K-S POA2-P POST DA-B2 POST POA 2 Subcat Reach On Link Routing Diagram for 2017-02-21 SWM POA 2 (AS -BUILT) Prepared by {enter your company name here), Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 3 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 131 -S: POST DA-1131 Runoff Area=1.220 ac 34.43% Impervious Runoff Depth=0.94" Flow Length=694' Tc=10.0 min CN=74 Runoff=1.12 cfs 0.096 of Subcatchment 132-S: POST DA-1132 Runoff Area=0.320 ac 31.25% Impervious Runoff Depth=0.89" Tc=5.0 min CN=73 Runoff=0.35 cfs 0.024 of Subcatchment 133-S: POST DA-1133 Runoff Area=0.460 ac 0.00% Impervious Runoff Depth=0.38" Tc=5.0 min CN=61 Runoff=0.12 cfs 0.015 of Pond B-P: DET PIPE Peak Elev=410.95' Storage=592 cf Inflow=1.22 cfs 0.110 of Outflow=0.63 cfs 0.110 of Link POA2-P: POST POA 2 Inflow=0.76 cfs 0.134 of Primary=0.76 cfs 0.134 of Total Runoff Area = 2.000 ac Runoff Volume = 0.134 of Average Runoff Depth = 0.80" 74.00% Pervious = 1.480 ac 26.00% Impervious = 0.520 ac 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 131-S: POST DA-131 Runoff = 1.12 cfs @ 12.10 hrs, Volume= 0.096 af, Depth= 0.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 0.800 61 >75% Grass cover, Good, HSG B 0.420 98 Paved roads w/curbs & sewers, HSG B 1.220 74 Weighted Average 0.800 65.57% Pervious Area 0.420 34.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 35 0.0850 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.69" 2.1 154 0.0580 1.20 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 1.8 220 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.3 285 0.0050 3.72 4.57 Pipe Channel, 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 Corruqated PE, smooth interior 10.0 694 Total 3 0 LL Subcatchment 131-S: POST DA-131 Hydrograph 1.12 cfs I LL I I Tinri elIand Park Z4-f rIS1 I1 lyr 17 1 71 .11 17 1 T 1 I I —I 1 1 T 11-1 RaInfa-1101.05" IIII l l l l l u l l l l Ru offlAlre�ar'�. 2 ac Runo Volume=0.096 of R6660 Depth - OI.94" l l l III I I I I I I I I I I I I IFloluvl L�engtl =P4� �c=10.0 min li �I�li i 'IIIIIIIIIIIIIIGI�=7� IIII illll 'II�IIIIIIIIIIIII�IIIIIIIII I' ��I� IIIII I'll IIII IIIIII Illli Ili 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment B2-S: POST DA-132 Runoff = 0.35 cfs @ 12.03 hrs, Volume= 0.024 af, Depth= 0.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 0.220 61 >75% Grass cover, Good, HSG B 0.100 98 Paved parking, HSG B 0.320 73 Weighted Average 0.220 68.75% Pervious Area 0.100 31.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment B2-S: POST DA-132 Hydrograph 0.38 0.36 0.34 0.35 cfs T �T 1 T I T IT 1 1 I I 1 1 I__�mber�aIn""r 2�- ir4l 11_-� 0.32 0.3 —1 — -LI T I LI I� -1 1 T I LI a I T I LI 1-1 1 Rainfall_OU-15'r 0.28 0.26 1 T I T I LI l I I i I D LI Ij I I I � o F Arena 0--_ act 0.24 0.22 I I-i I T I L I L 1 1 1 L I Q l uno Volume— a ITI L I MjtiolFf I Dle0ht 01.�b'r — _L o0°$T ITI I TITITI TITITIT T TI��-'0 ' U. 0.16 1 T ITI TI T IT IT TI F1 IT IT TI l 1 0.14 — — — — 001 I ITI TI T IT ICI TI T IT ITI TI T 0.06 1— -- ITI TI T I— -1 T IT IT I TI T I — — 0.04 1T IT T IT I ITI fit T Irt ITI T T 1rt 1rtI T 1T 0.02 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment B3-S: POST DA-133 Runoff = 0.12 cfs @ 12.05 hrs, Volume= 0.015 af, Depth= 0.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 1-yr Rainfall=3.05" Area (ac) CN Description 0.460 61 >75% Grass cover, Good, HSG B 0.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment B3-S: POST DA-133 Hydrograph 0.13 0.125 0.12 0.12 cfs — _ — _� — — -Runoff 0.115 0.11 1 IH H I� H a - TimbeFFYYddnfl-r rk 2firIS1 �- r o o f H H H RaWall=3� 0$'r 0.095 0.09 1 t I H I t I HI fi 11 Ama�_6 �o.os5 t5 uno;off Volurtre= a o 075 H I H 14 H kbriotf D Otlr�". u 0.07 �_ �I �I H I� �I I� �1�04 _00,065 u_ 0,0557 _i_ 6� I 14 -I- -I- H I+ I H I H 14 H I H I H 14 H I H I HI 0.045 U. 0.035 H ICI. H C� ICI H H ICI H H ICI H 35 0.03 0.025-I IH IHI. �I H IHI HI H IH IHI HI H IH I_�I HI H 0.02 0 0.01 H H. H H � !- I H H H 14- H �H .01 0.005 0 1 2 3 4 5 6 7 8 9 10 11 1213 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 7 Summary for Pond B-P: DET PIPE Inflow Area = 1.680 ac, 25.00% Impervious, Inflow Depth = 0.79" for 1-yr event Inflow = 1.22 cfs @ 12.10 hrs, Volume= 0.110 of Outflow = 0.63 cfs @ 12.32 hrs, Volume= 0.110 af, Atten= 48%, Lag= 13.7 min Primary = 0.63 cfs @ 12.32 hrs, Volume= 0.110 of Routing by Dyn-Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 410.95' @ 12.32 hrs Surf.Area= 724 sf Storage= 592 cf Plug -Flow detention time= 8.9 min calculated for 0.110 of (100% of inflow) Center -of -Mass det. time= 8.9 min ( 903.4 - 894.5 ) Volume Invert Avail.Storage Storage Description #1 409.81' 1,767 cf 36.0" Round Pipe Storage x 2 L= 125.0' S= 0.0006 T Device Routing Invert Outlet Devices #1 Primary 409.76' 18.0" Round Culvert L= 7.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet / Outlet Invert= 409.76' / 409.65' S= 0.0157 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 409.81' 5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 411.31' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.50 0.50 3.00 Width (feet) 0.50 0.50 3.00 3.00 Primary OutFlow Max=0.63 cfs @ 12.32 hrs HW=410.95' TW=0.00' (Dynamic Tailwater) L1=Culvert (Passes 0.63 cfs of 4.44 cfs potential flow) N =Orifice/Grate (Orifice Controls 0.63 cfs @ 4.66 fps) =Custom Weir/Orifice ( Controls 0.00 cfs) 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 8 Pond B-P: DET PIPE Hydrograph 1.22 cfs III in,f`owl�mmra11.66 acl 1 1 1 1 l l l l l l l l l ealk�114V=4'�AI. 5�I IIIIIIIIII Siol real lel__15921 cfl IIIIIII II IIIIIIIIIIIIIII�IIHIM 0.63 cfs IIII (IIII (IIIIIII II IIIIIIIIIIIIIIIIIIIIII �I IIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIII I Il IIIIII�IIIlllllll �I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow — Primary 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 1-yr Rainfall=3.05" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 9 Summary for Link POA2-P: POST POA 2 Inflow Area = 2.000 ac, 26.00% Impervious, Inflow Depth = 0.80" for 1-yr event Inflow = 0.76 cfs @ 12.24 hrs, Volume= 0.134 of Primary = 0.76 cfs @ 12.24 hrs, Volume= 0.134 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Link POA2-P: POST POA 2 Hydrograph 0.85 0.8 - 0.76 cfs - - Inflow - Primary 0.75 —� -�- - - — - InffowAma�-2. 0.7 0.65 - - ad - 0.6 0.55 I- T P F _T M TI 0.5-IH IfilHH + -IHI- + -IHI 0.45 0 0.4 — — — I — — — — — — _t I 4-1 - - I 4- I — k-1 — I - — — — — I 4- I N 14 I 0.35 IIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIII 0.3 - 0.2 — — — — — - 0.15 -� -k I-t 4--I I-t -I I --I I- 14I -k-I N I4 I 0.1 — — — — — — — - 0.05 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 10 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 131 -S: POST DA-1131 Runoff Area=1.220 ac 34.43% Impervious Runoff Depth=2.84" Flow Length=694' Tc=10.0 min CN=74 Runoff=3.28 cfs 0.288 of Subcatchment 132-S: POST DA-1132 Runoff Area=0.320 ac 31.25% Impervious Runoff Depth=2.74" Tc=5.0 min CN=73 Runoff=1.04 cfs 0.073 of Subcatchment 133-S: POST DA-1133 Runoff Area=0.460 ac 0.00% Impervious Runoff Depth=1.73" Tc=5.0 min CN=61 Runoff=0.87 cfs 0.066 of Pond B-P: DET PIPE Peak Elev=412.14' Storage=1,451 cf Inflow=3.94 cfs 0.355 of Outflow=3.78 cfs 0.355 of Link POA2-P: POST POA 2 Inflow=4.42 cfs 0.428 of Primary=4.42 cfs 0.428 of Total Runoff Area = 2.000 ac Runoff Volume = 0.428 of Average Runoff Depth = 2.57" 74.00% Pervious = 1.480 ac 26.00% Impervious = 0.520 ac 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 131-S: POST DA-131 Runoff = 3.28 cfs @ 12.09 hrs, Volume= 0.288 af, Depth= 2.84" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 0.800 61 >75% Grass cover, Good, HSG B 0.420 98 Paved roads w/curbs & sewers, HSG B 1.220 74 Weighted Average 0.800 65.57% Pervious Area 0.420 34.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 35 0.0850 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.69" 2.1 154 0.0580 1.20 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 1.8 220 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.3 285 0.0050 3.72 4.57 Pipe Channel, 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 Corruqated PE, smooth interior 10.0 694 Total 3 2 3 0 LL 0 Subcatchment B1-S: POST DA-131 Hydrograph II��II�IIIIIIII f� IIIIIII III Timbe�lanld IPar� 241-1�r Sli Iio!y� l I I I Ralnfall�0.581' trifQlr Area=1.T ac V Ruf olume=0.2 8 of Runoff Qepth= ?.84" I I I I Flo nth==' k I�--1 -I— �_I 14 1 4- I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) —Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment B2-S: POST DA-132 Runoff = 1.04 cfs @ 12.03 hrs, Volume= 0.073 af, Depth= 2.74" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 0.220 61 >75% Grass cover, Good, HSG B 0.100 98 Paved parking, HSG B 0.320 73 Weighted Average 0.220 68.75% Pervious Area 0.100 31.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, 3 0 U. Subcatchment B2-S: POST DA-132 Hydrograph 1.04 cfs - - Timhe�Ian-� (Park 24-hr S1 10-yr i IIIIIIIIIIIIIIIII Rainfall=5.58" R n ff AA1rea=O. 0 ac �un Wf olume �0.0�3� alf Runoff Depth,=2.74',' Tc=50min 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment B3-S: POST DA-133 Runoff = 0.87 cfs @ 12.03 hrs, Volume= 0.066 af, Depth= 1.73" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 10-yr Rainfall=5.58" Area (ac) CN Description 0.460 61 >75% Grass cover, Good, HSG B 0.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment B3-S: POST DA-133 Hydrograph 0.95 0.9 — — 0.87 cfs 0.85 + + + + + +1 I_4Tir_�Ib1e�Ialntl Park 4_-Lhlr S1 10-ye 0.8 0.75 Rafinfall=5.581' 0.7 0.65 + + + 1 1 + + + N Runoff Area=0.4611f1� ,aa +R�u�ff'VoIu-me=u.0661a 0, 5 + I- -I- I- -I_ 1 I + 1 I + I +I +ROnqff�epth=11.73�' —' 0.5 0 0.45 - + + + +1 + 1+ + Tc=5.0 mi + + + I +IY=O 1 LL 0.4 +I L III + + + +III+ 0.35 0.3 + +. + + + +I + + + 0.25 — — — — — — — — — — — — — — — 0.5+ _1 IT + + I++III + +I+I+ 1+ 1+I+I+ 1+ 1 0.1 +1+ +I + 1 +I _rI + +I+I+I + +I+I+I + 0.05 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 14 Summary for Pond B-P: DET PIPE Inflow Area = 1.680 ac, 25.00% Impervious, Inflow Depth = 2.53" for 10-yr event Inflow = 3.94 cfs @ 12.08 hrs, Volume= 0.355 of Outflow = 3.78 cfs @ 12.11 hrs, Volume= 0.355 af, Atten= 4%, Lag= 2.1 min Primary = 3.78 cfs @ 12.11 hrs, Volume= 0.355 of Routing by Dyn-Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 412.14' @ 12.11 hrs Surf.Area= 636 sf Storage= 1,451 cf Plug -Flow detention time= 9.7 min calculated for 0.354 of (100% of inflow) Center -of -Mass det. time= 9.7 min ( 868.5 - 858.8 ) Volume Invert Avail.Storage Storage Description #1 409.81' 1,767 cf 36.0" Round Pipe Storage x 2 L= 125.0' S= 0.0006 T Device Routinq Invert Outlet Devices #1 Primary 409.76' 18.0" Round Culvert L= 7.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet / Outlet Invert= 409.76' / 409.65' S= 0.0157 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 409.81' 5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 411.31' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.50 0.50 3.00 Width (feet) 0.50 0.50 3.00 3.00 Primary OutFlow Max=3.77 cfs @ 12.11 hrs HW=412.14' TW=0.00' (Dynamic Tailwater) L1=Culvert (Passes 3.77 cfs of 10.87 cfs potential flow) N =Orifice/Grate (Orifice Controls 0.96 cfs @ 7.02 fps) =Custom Weir/Orifice (Weir Controls 2.81 cfs @ 2.26 fps) 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 15 Pond B-P: DET PIPE Hydrograph No 3 0 LL Inflow'Are1a'=1.680 ad Leak ev 141112L'�� H HI H IH H -I H H - -I HI I- toragge= ,451 cf III IIIIIIII IIIIIIITIIIIIIIII IIIHIM IIIIIIIIIIIIIIIIII I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow — Primary 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 10-yr Rainfall=5.58" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 16 Summary for Link POA2-P: POST POA 2 Inflow Area = 2.000 ac, 26.00% Impervious, Inflow Depth = 2.57" for 10-yr event Inflow = 4.42 cfs @ 12.11 hrs, Volume= 0.428 of Primary = 4.42 cfs @ 12.11 hrs, Volume= 0.428 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Link POA2-P: POST POA 2 Hydrograph N w V 3 0 LL 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Inflow — Primary 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 17 Time span=1.00-40.00 hrs, dt=0.01 hrs, 3901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 131 -S: POST DA-1131 Runoff Area=1.220 ac 34.43% Impervious Runoff Depth=5.98" Flow Length=694' Tc=10.0 min CN=74 Runoff=5.73 cfs 0.607 of Subcatchment 132-S: POST DA-1132 Runoff Area=0.320 ac 31.25% Impervious Runoff Depth=5.85" Tc=5.0 min CN=73 Runoff=1.80 cfs 0.156 of Subcatchment 133-S: POST DA-1133 Runoff Area=0.460 ac 0.00% Impervious Runoff Depth=4.35" Tc=5.0 min CN=61 Runoff=1.91 cfs 0.167 of Pond B-P: DET PIPE Peak Elev=412.45' Storage=1,627 cf Inflow=7.21 cfs 0.774 of Outflow=7.17 cfs 0.774 of Link POA2-P: POST POA 2 Inflow=8.57 cfs 0.930 of Primary=8.57 cfs 0.930 of Total Runoff Area = 2.000 ac Runoff Volume = 0.930 of Average Runoff Depth = 5.58" 74.00% Pervious = 1.480 ac 26.00% Impervious = 0.520 ac 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 131-S: POST DA-131 Runoff = 5.73 cfs @ 12.09 hrs, Volume= 0.607 af, Depth= 5.98" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 0.800 61 >75% Grass cover, Good, HSG B 0.420 98 Paved roads w/curbs & sewers, HSG B 1.220 74 Weighted Average 0.800 65.57% Pervious Area 0.420 34.43% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.8 35 0.0850 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.69" 2.1 154 0.0580 1.20 Shallow Concentrated Flow, Woodland Kv= 5.0 fps 1.8 220 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.3 285 0.0050 3.72 4.57 Pipe Channel, 15.0" Round Area= 1.2 sf Perim= 3.9' r= 0.31' n= 0.013 Corruqated PE, smooth interior 10.0 694 Total 3 0 LL Subcatchment B1-S: POST DA-131 Hydrograph III � 3 — �I Tim�rlar dl Pay k12�-hr SI'1 '100-yr + I -I- I --I RainfaII79.16" I � R�n�o�ff � r�a=1.��0 ac u ff o 7 of I I I Runoff Ppp�h�§.981' I�cInaOhO�rri94� IIIIIIIIIIIIIIIIIIIII��-17� IIIIIIIIIIIIIII�II�IIIIII IIIIIIIIIIIIIIIIIIIIIIIII 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 19 Summary for Subcatchment B2-S: POST DA-132 Runoff = 1.80 cfs @ 12.03 hrs, Volume= 0.156 af, Depth= 5.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 0.220 61 >75% Grass cover, Good, HSG B 0.100 98 Paved parking, HSG B 0.320 73 Weighted Average 0.220 68.75% Pervious Area 0.100 31.25% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment B2-S: POST DA-132 Hydrograph T T Fi i i i I, i i i i i i iI 'fimi)�rlar dl Park12�-hr S1 11001yr- I I I Rainfallr9.16'' I %noff rea=0.%10 ac ua0.1 6 ofu oI 1 I I Runoff Depth,=5.85'' T I T T IT T T I T T T Tc=5 O min 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 20 Summary for Subcatchment B3-S: POST DA-133 Runoff = 1.91 cfs @ 12.03 hrs, Volume= 0.167 af, Depth= 4.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Timberland Park 24-hr S1 100-yr Rainfall=9.16" Area (ac) CN Description 0.460 61 >75% Grass cover, Good, HSG B 0.460 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment B3-S: POST DA-133 Hydrograph 1.91 cfs Timberland Park 24-hr S1 100-yr Rainfall=9.16" l l l l l l l l l l l l l l l Runoff Area=0.460 ac Runoff Volume=0.167 of HIMM111H Runoff Depth=4.35" I -I I 1 -I-1 J Tc=5.0 min CN=61 IIIIIIIII III Illllilll II IIIIIIIII III IIIIII'!' IIIIII 1 2 3 4 5 6 7 777777713 14151617181920212272725 26 27 2'8 29 30 31 32 33 34 35 36 37 38 39 4i Time (hours) — Runoff 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here) Printed 2/3/2020 HydroCAD®10.00-25 s/n 07714 ©2019 HydroCAD Software Solutions LLC Page 21 Summary for Pond B-P: DET PIPE Inflow Area = 1.680 ac, 25.00% Impervious, Inflow Depth = 5.53" for 100-yr event Inflow = 7.21 cfs @ 12.07 hrs, Volume= 0.774 of Outflow = 7.17 cfs @ 12.08 hrs, Volume= 0.774 af, Atten= 1 %, Lag= 0.7 min Primary = 7.17 cfs @ 12.08 hrs, Volume= 0.774 of Routing by Dyn-Stor-Ind method, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Peak Elev= 412.45' @ 12.08 hrs Surf.Area= 510 sf Storage= 1,627 cf Plug -Flow detention time= 9.4 min calculated for 0.774 of (100% of inflow) Center -of -Mass det. time= 9.4 min ( 849.4 - 840.0 ) Volume Invert Avail.Storage Storage Description #1 409.81' 1,767 cf 36.0" Round Pipe Storage x 2 L= 125.0' S= 0.0006 T Device Routinq Invert Outlet Devices #1 Primary 409.76' 18.0" Round Culvert L= 7.0' RCP, sq.cut end projecting, Ke= 0.500 Inlet / Outlet Invert= 409.76' / 409.65' S= 0.0157 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #2 Device 1 409.81' 5.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 411.31' Custom Weir/Orifice, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.50 0.50 3.00 Width (feet) 0.50 0.50 3.00 3.00 Primary OutFlow Max=7.16 cfs @ 12.08 hrs HW=412.45' TW=0.00' (Dynamic Tailwater) L1=Culvert (Passes 7.16 cfs of 11.84 cfs potential flow) N =Orifice/Grate (Orifice Controls 1.02 cfs @ 7.50 fps) =Custom Weir/Orifice (Weir Controls 6.14 cfs @ 2.84 fps) 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 22 3 0 LL am rt Irtl fil h Pond B-P: DET PIPE Hydrograph InOW Area lI 6� � ac IstorEh qII ��I I �161, f IIIIIIIIIIIIIIITIIII M T I fi I ri I I I rt 1 1-1 rI II I rt I fi I �1 4-1 -k- I k I4 141 4- I �-1 I-t 14 1 4- 1 t-1 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Time (hours) wM"o n er" 31323334 Inflow — Primary 2017-02-21 SWM POA 2 (AS -BUILT) Timberland Park 24-hr S1 100-yr Rainfall=9.16" Prepared by {enter your company name here} Printed 2/3/2020 HydroCADO 10.00-25 s/n 07714 © 2019 HydroCAD Software Solutions LLC Page 23 Summary for Link POA2-P: POST POA 2 Inflow Area = 2.000 ac, 26.00% Impervious, Inflow Depth = 5.58" for 100-yr event Inflow = 8.57 cfs @ 12.07 hrs, Volume= 0.930 of Primary = 8.57 cfs @ 12.07 hrs, Volume= 0.930 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 1.00-40.00 hrs, dt= 0.01 hrs Link POA2-P: POST POA 2 Hydrograph 3 0 U. ' illlll 'Ili � III � 3 8.57 cfs 3 M I H �� fjo � �.�r IIIIIIIIII Illllllllllllllllllllll � IIIIIIIlllllllllT ' Illllllllllll�il�illiiliilliiliillii IIITIPIII 1 _ I it � I r 1 1 1 I_1 IT l 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) — Inflow — Primary STORM SEWER DESIGN � �) 4 >i Froill' TimW.tl 11. Apart eets-AS-BUILT 10 YEARFREQUENCY J�bn 34160034 ``��''y3 �I Date'. 21312020 IOF CURVE REFERENCE: ALBEMARLE CO. By DKO FROM TO DA CA TC RAINFALL RUN-OFF INVERT INVERT LENGTH DIAM. MANNING'S CAPACITY VELOCITY FLOWTIME PERCENT POINT POINT (ACRES) C INCR. ACCUM. (MINUTES) (INIHR) (CFS) LINE UPPER LOWER (FEET) SLOPE (INCHES) N COEFF. (CFS) (F.P.S.) (MINUTES) CAPACITY 12 10 0.02 0.63 0.01 0.01 5.00 6.67 0.08 11 430.73 430.42 9.83 3.15% 12 0.011 7.47 3.11 0.05 0.01 10 8 0.31 0.69 0.21 0.23 5.05 6.65 1.50 9. 430.32 429.85 59.08 0.80% 15 0.011 6-81 4.44 0.22 0.22 8 6 0.00 0.00 0.00 0.23 5.27 6.57 1.48 7 429.75 429.18 83.34 0.68% 15 0.011 6.31 4.20 0.33 0.23 6 4 0.23 0.83 0.19 0.42 5-61 6.47 2.69 5 429.08 426.34 184.83 1.48% 15 0.011 9.29 6.58 0.47 0.29 4 2 0.82 0.77 0.63 1.05 6.07 6.33 6.64 3 426.24 425.11 114.52 0.99% 18 0.011 12.33 7.12 0.27 0.54 2 1 0.27 0.74 0.20 1.25 6.34 6.25 7.80 1A 425A1 424.92 87.25 0.22% 24 0.011 12.47 4.16 0.35 0.63 1 IOUT 0.00 0.00 0.00 1.25 6.69 6.15 7.68 1B 424.92 424.23 41.07 1.68% 24 0.011 34.64 8.85 0.08 0.22 20 18 0.12 0.58 0.07 0.07 5.00 6.67 0.46 19 413.40 410.72 88.85 3.02% 15 0.011 13.25 4.97 0.30 0.03 18 16 1.10 0.54 0.59 0.66 5.30 6.57 4.32 17 4%62 410.04 138.47 0.42% 18 0.011 8.03 4.64 0.50 0.54 16 14 0.18 0.35 0.06 0.72 5.80 6.41 4.62 15 409.94 409.86 128.53 0.06% 36 0.011 19.66 2.27 0.94 0.24 14 130UT 0.28 0.35 0.10 0.82 6.74 6.14 5.03 13 409.76 409.65 7.01 L57% 18 0.011 15.55 7-91 0.01 0.32 36 34 0.44 0.49 0.21 0.21 5.00 6.67 1.43 35 442.93 442.85 37.13 0.22% 12 0.011 1.95 2.68 0.23 0.73 34 32 0.00 0.00 0.00 0.21 5.23 6.59 1.41 33 442.85 441.63 108.42 1.13% 12 0.011 4.46 5.08 0.36 0.32 32 30 0.00 0.00 0.00 0.21 5.59 6.48 1.39 31 441.63 440.22 118.60 1.19% 12 0.011 4.59 5.15 0.38 0.30 30 28 0.11 0.60 0.07 0.28 5.97 6.36 1.78 29 440.22 431143 31.56 5.67 % 12 0.011 10.02 9.59 0.05 0.18 28 28 0.00 0.00 0.00 0.28 6.03 6.34 1.78 27 438.43 436.18 67.59 3.33% 12 0.011 7.68 7.95 0.14 0.23 26 24. 0.08 0.69 0.06 0.34 6.17 6.30 2.12 25 436A8 435.66 20.62 2.52% 12 0.011 6.68 7.60 0.05 0.32 24 22 0.00 0.00 0.00 0.51 6.21 6.29 3.20 23 435.66 435.57 50.77 0.18% 12 0.011 1.77 2.26 0.38 1.80 22 21OUT OAO 0.00 0.00 0.51 6.59 6.18 3A4 21 435.57 434.71 39.58 2A7% 12 0.011 6.20 7.99 0.08 0.51 38 24 0.32 0.54 0.17 0.17 13.52 4.76 0.82 37 437.35 435.66 67.71 2.50% 12 0.011 6.65 5.70 0.20 0.12 42 40 0.27 0.55 0:15 0.15 5.00 6.67 1.00 41 410.55 410.48 12.03 0.61 % 15 0.011 5.94 3.57 0.06 0.17 40 39OUT 0.00 0.00 0.00 OA5 5.06 6.65 0.99 39 410.48 409.65 135A2 0.61% 15 11 5.98 3.59 0.63 0.17 PROJECT: Timberland Park Apartments -AS-BUILT - - - - PROJECT NO: 34160034 CREATED BY: DKO DATE: February 3, 2020 10 YEAR RETURN FREQUENCY HYDRAULIC GRADE LINE CALCULATIONS OUTLET WATER INLET WATER INLET STATION SURFACE ELEV. Do Qo Lo Sfo Hf JUNCTION LOSS FINAL H SURFACE ELEV. RIM ELEV. Vo Ho Qi Vi QiVi ViA2/2g Hi ANGLE I HA Ht 1.3Ht 0.5Ht 1 2 425.83 24" 7.68 41.07 0.12 0.05 2.44 0.02 7.80 4.16 32.42 0.27 0.09 25 0.06 0.18 1 0.22 426.05 430.39 2 4 426.52 24" 7.80 87.25 0.12 0.10 2.48 0.02 6.64 2.48 16.49 0.10 0.03 42 0.04 0.10 0.20 426.72 428.31 4 6 426.72 18" 6.64 114.52 0.40 0.46 3.76 0.05 2.69 6.58 17.72 0.67 0.24 78 0.44 0.73 0.95 1.40 428.12 429.05 6 8 428.12 15' 2.69 184.83 0.17 0.32 2.19 0.02 1.48 4.20 6.23 0.27 0.10 41 0.11 1 0.22 0.29 0.61 428.73 432.53 8 10 430.18 1 15' 1.48 83.34 0.05 0.04 1.21 0.01 1.50 4.44 6.66 0.31 0.11 49 0.14 0.25 0.30 430.48 436.14 10 12 430.85 15' 1.50 59.08 0.05 0.03 1.22 0.01 0.08 3.11 0.26 0.15 0.05 31 0.04 0.10 0.13 0.16 431.01 433.53 12 431.22 12" 0.08 9.83 0.00 0.00 0.11 0.00 0.00 0.00 0.00 431.22 434.08 0.00 14 • 16 410.85 18" 5.03 7.01 0.23 0.02 2.84 0.03 4.62 2.27 10.50 0.08 0.03 3 0.00 0.06 0.08 413.51 414.65 16 18 413.51 36" 4.62 128.53 0.00 1 0.01 0.65 0.00 4.32 4.64 20.05 0.33 0.12 3 0.01 0.13 0.13 413.64 417.29 18 20 413.64 18" 4.32 138.47 0.17 0.23 2.45 0.02 0.46 4.97 2.30 0.38 0.13 19 0.06 0.21 0.28 0.14 0.37 414.01 414.20 20 414.01 15' 0.46 88.85 0.01 0.00 0.38 0.00 0.00 0.00 0.01 414.02 416.39 0.00 40 42 410.65 15' 0.99 135.12 0.02 0.03 0.81 0.00 1.00 3.57 3.56 0.20 0.07 87 0.14 0.21 0.24 413.51 414A9 42 413.51 15' 1.00 12.03 0.02 0.00 0.81 0.00 0.00 0.00 0.01 413.52 412.25 0.00 22 24 435.51 12" 3.14 39.58 0.78 0.31 4.00 0.06 3.20 2.26 7.21 0.08 0.03 0 0.00 0.09 0.40 435.91 440.29 24 26 436.37 12" 3.20 50.77 0.80 0.41 4.07 0.06 2.12 7.60 16.09 0.90 0.31 90 0.63 1.01 1.41 437.78 439.43 26 28 437.78 12" 2.12 20.62 0.35 0.07 2.69 0.03 1.78 7.95 14.14 0.98 0.34 0 0.00 0.37 0.44 438.22 441.10 28 30 438.22 12" 1.78 67.59 0.25 0.17 2.26 0.02 1.78 9.59 17.09 1.43 0.50 0 0.00 0.52 0.69 438,91 442.50 30 32 439.23 12" 1.78 31.56 0.25 0.08 2.27 0.02 1.39 5.15 7.15 0.41 0.14 31 0.12 0.28 0.37 0.45 439.68 443.12 32 34 441.02 12" 1.39 118.60 0.15 0.18 1.77 0.01 1.41 5.08 7.18 0.40 0.14 31 0.12 0.27 0.45 441.47 445.65 34 36 442.43 12" 1.41 108.42 0.16 0.17 1.80 0.01 1.43 2.68 3.83 0.11 0.04 45 0.05 0.10 0.27 442.70 447.14 36 443.65 12" 1.43 37.13 0.16 0.06 1.82 0.01 0.01 0.02 0.08 443.73 445.87 0.00 24 38 436.37 12" 3.20 50.77 0.80 0.41 4.07 0.06 0.82 5.70 4.67 0.50 0.18 0 0.00 0.24 0.65 437.02 439.43 38 437.02 12" 0.82 67.71 0.05 0.04 1.04 0.00 0.00 0.01 0.04 437.06 439.35 0.5 H1= INLET SHAPING SF. = FRICTION SLOPE (Oo-OijlOo= X 1.3 Ht= DROP INLET Hf = FRICTION LOSS OROP INLET X H"=BEND LOSS Ho= CONTRACTION LOSS MANHOLE X120% Ht=TOTAL HEAD LOSS HI=EXPANSION LOSS SPECIFICATION #9 - BIORETENTION BASIN A WORKSHEET Design Level Level #2 BMP Sizing Data Transcribed Runoff Reduction Worksheet PROJECT NAME: PROJECT #: DATE: BY: Treatment Volume (Tv) Level #2 Impervious 3,684 (cf) Level #2 Turf (cf) Timberland Park Apartments - AS -BUILT 34160034 2/3/2020 DKO Treatment Level Treatment Volume Total Coefficient (Tv) TVBMP 1.25 * 3,684 (cf) = 4,606 (cf) Equivalent Storage Depth Surface Storage 0.50 (ft) Bioretention Soil Media & Mulch 3.00 (ft) Choker Stone 0.33 (ft) Additional Gravel 2.00 (ft) Required Gravel Below Underdrain 1.00 (ft) Total Depth 6.83 (ft) Required Surface Area Treatment Volume Equivalent Storage Depth Pond Design Elevations (ft Top of Bioretention Berm Top of Storage, High Flow Weir, Top of Riser P.T. Cell Low Flow Weir Top of Media Bottom of Media / Geotextile Fabric Bottom of Choker Stone Underdrain Invert Bottom of Gravel Flow Path Pre -Treatment Measures Length of shortest flow path w/ >20% contributing DA Overall length Ratio Measure 1 Measure 2 4,606 2.58 Inflow Area (A) Impervious 0.86 (ac) Turf 0.99 (ac) Void Ratios Storage Equiv. 1 0.50 (ft) 0.25 0.75 (ft) 0.4 0.13 (ft) 0.4 0.80 (ft) 0.4 0.40 (ft) 2.58 (ft) =1784 (sf) Pre -Treatment Cell 435.92 434.19 433.94 433.69 430.69 430.36 428.36 427.36 80 (ft) 100 (ft) 0.80 No Baffle Required Pre -Treatment Cell Design Design Cell Surface Area 465 (sf) Design Cell Depth 1.50 (ft) Provided Storage 698 (cf) Required Storage (TvBMP*0.15) 691 (cf) Suggested Plant Material 7 (ea.) Trees, 1" Caliper Minimum (and) 1 per 250 (sf) SPECIFICATION #9 - BIORETENTION BASIN A WORKSHEET Design Level Level #2 PROJECT NAME: PROJECT #: DATE: BY: Timberland Park Apartments - AS -BUILT 34160034 2/3/2020 DKO BMP Sizing Data Transcribed Runoff Reduction Worksheet Inflow Area (A) Treatment Volume (Tv) Level #2 Impervious 5,224 (cf) Impervious 1.30 (ac) Level #2 Turf (cf) Turf 1.02 (ac) Treatment Level Treatment Volume Total Coefficient (Tv) TVBMP 1.25 * 5,224 (cf) = 6,529 (cf) Equivalent Storage Depth Void Ratios Storage Equiv. Surface Storage 0.50 (ft) 1 0.50 (ft) Bioretention Soil Media & Mulch 3.00 (ft) 0.25 0.75 (ft) Choker Stone 0.33 (ft) 0.4 0.13 (ft) Required Gravel Below Underdrain 1.00 (ft) 0.4 0.40 (ft) Additional Gravel 1.00 (ft) 0.4 0.40 (ft) Total Depth 5.83 (ft) 2.18 (ft) xequireO Nurrace Area Treatment Volume 6,529 = 2992 (sf) Equivalent Storage Depth 2.18 Pond Design Elevations (ft Top of Bioretention Berm Top of Storage, High Flow Weir, Top of Riser P.T. Cell Low Flow Weir Top of Media Bottom of Media / Geotextile Fabric Bottom of Choker Stone Underdrain Invert Bottom of Gravel Flow Path Pre -Treatment Measures Length of shortest flow path w/ >20% contributing DA Overall length Ratio Measure 1 Measure 2 Grass Filter Strip Pre -Treatment Cell 426.49 424.59 424.34 424.09 421.09 420.76 420.76 418.76 80 (ft) 100 (ft) 0.80 No Baffle Required Pre -Treatment Cell Design Design Cell Surface Area 667 (sf) Design Cell Depth 1.50 (ft) Provided Storage 1,001 (cf) Required Storage (TvBMP*0.15) 979 (cf) Suggested Plant Material 12 (ea.) Trees, V Caliper Minimum (and) 1 per 250 (sf)