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HomeMy WebLinkAboutWPO202200050 Calculations 2023-02-23SHIMP ENGINEERING, P.C. Design Focused Engineering February 22, 2023 O Engineering Review 5183 4 i 2I , No. Albemarle County 1�3 Department of Community Development kOOA.. 401 McIntire Road d� Charlottesville, VA 22902 SS1ONAL Regarding: WP02022-00050 Forest Lakes Self Storage Stormwater Management Plan Dear Reviewer, The purpose of this project is to construct a self -storage facility. The total area of disturbance is 3.14 acres. Water Quantity: The stormwater management for this site will be addressed through the use of a detention pond. The pond will release runoff at rates compliant with the Energy Balance Equation. Summaries of the pre and post development flow rates at the point of analysis are shown below. Please see drainage area maps located in this packet for more detail. This site is compliant with water quantity requirements by meeting 9VAC25-870-66-B.3.a. Channel Protection: Energy Balance Equation with Ran -on for POA 1 Forest Lakes Self Storage 1 Yr, 24 Hr Storm Comparison Q 1e. -Qtnasm((RV tnase)i(RV ta.as..)xIF)'Q tara.evo((RV i en.mu,),(RV sv.w,.em)) IF - 0 8 when LOD 21 ac. 31 -0.9 whea LOD _ 1 ac, IF -10 when predev site is fully forested PreDev Site Fully Forested+ - no LF - 08 Limits of Dmtwbwce - 3 14 ac Onsite Offshe DevArea Omae - 286 ac Pre Dei, DA Otrsne - 042 ac Post Dev Area Omite - 3.10 ac Post Dcv DA OffSac - 0 68 ac Q 1pr.,sm - 380 cfs Qtmaorsv - 076 cfs Vfraasaa - 0.294 of RVrwaoma - 0059 of Vitswsin 0503 of RVsraso 0082 of Regulatorw Alavmum Postdei 1-)r Flow Rate Alai Qawv - 231 cfs Acldeied Design Postdev 1-yr Flow Rate Design Qiw - 2.11 Qs Energy Balance Egaation Compliance Check: Achies ed Notes; l The assmipvov m die Wculattov abm'e is that the site equals fhe 1o1.dntm6mg x wy (LDA). Die defrnihov for'sire ss vut dearly defined m We tegdabom, but LDAs are defrved as regulated The water quav4ty-mtena are applied m the me as peg the regdntmm. 211ns srte durhugesmmoW&d at av exishag daivuge svviceme Smce posfMelapmeaf nmoHto Phis omfall axeh�evergy bdavice egasbon CLarmel }totectiw Aegrmevrems per9\'AC25-870-66-B3 a are mn, avd chavvel psotectiov gequrrevrmh art mmBN. Concentrated runoff from this site is discharged to an existing storm structure. It is assumed that the existing structure is inadequate so reduction in the 10-yr flow rate is sufficient to meet flood protection requirements set forth in 9VAC25-870-66-C.2.b. Flood Protection: Peak Flow Rate to Existing Drainage Structure for POA 1 Forest Lakes Self Storage 10 Yr, 24 Fir Storm Comparison Regulatory Maximum 10-yr Flow Rate Qtarre = Max Qlaroo = 12.02 cis Achieved Design Postdev 10-yr Flow Rate Design Qiot t = 11.28 cis Flood Protection Compliance Check: Achieved otes: 1. It is assumed that the existing drainage structure is inadequate prior to reaching 1 % of the watershed. Water Quality: According to the VRRM New Development Compliance Spreadsheet, a TP Load Reduction of 3.34 lb/yr is required. The nutrient treatment requirement will be met through the purchase of nutrient credits. Best Regards, Chris Marshall, EIT Shimp Engineering, P.C. Contents: Pre -Development Stormwater Management Calculations: Pre -Development Drainage Area Map Pre -Development HydroCAD Analysis Time of Concentration Calculation Time of Concentration Nomographs Post -Development Stormwater Management Calculations: Post -Development Drainage Area Map Post -Development HydroCAD Analysis Energy Balance Equation Summary LD-204 Stormwater Inlet Computations LD-229 Storm Drain Design Computations Outlet Protection Calculations Stormwater Quality Calculations: VRRM Pre -Development Land Use Map VRRM Post -Development Land Use Map VRRM Re -Development Spreadsheet Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report Pre -Development Stormwater Management Calculations: Pre -Development Drainage Area Map Pre -Development HydroCAD Analysis Time of Concentration Calculation Time of Concentration Nomographs FOREST LAKES SELF STORAGE PREDEV DRAINAGE AREA MAP ){LEVEN ' I / I Drainage Area 1: � 1 � IF I P➢VAM E � Total Area = 3.28 ac PARTS ~ °1 OFFSITE DRAINAGE v 1 OR I AREA TO POA 1 Onsite Area = 2.86 ac \ 40 � M EASENNI \ Managed Turf = 2.86 ac (HSG D) 10]1 PG 49] DO Impervious = 0.00 ac TMP TO OB 1169 PG 3W k 341 \ N�,ZI.IT 40.OV O.Otl N/P GECRMERCERMARY R. it \ \ 81 OG 35R35 C 94 (PLAT) rJ Offsite Area = 0.42 ac \ _ _ J Managed Turf = 0.29 ac (HSG D) \\ L \ NNGINIA TEIEPHCNE k DO °RAP" 495 SENT Impervious = 0.13 ac (HSG D) V GB MO P° 103 /F DEC \ O5 i5 9 PG e I Time of Concentration 20.5 Ga A6]z Pc 153 (PEAT) A �A \ ♦ p OFFSITE DRAINAGE e V1AEU MOTH AC \ I I \ ar` A°'ACCESS EASEMENT \ A SAkIT/.Rr EASEMENT 08 na] Pc wA AREA TO PICA 1 v G6 ]k2 56 " / \ N3993'59'E 15850' IV C 0]SSY6 NI 1 SEMENT \ `� ,MP 468H3 \ I I 1 I I V. \ N/F JA-ZAN MMITEO PARTNERSHIP z,.M PE-CE 1 DO 11896PAC347 �\ ONSITE DRAINAGE I I AREA TO PICA VP a66a-s \ o \ \ \ \ \ NI 1-UN 11MITE0 PARTNERSHIP \ MOD LION \ _ I I / DZONED PD-SC O 1144 PC 8 VANMLE USEMFNORM SENEA / yn I /00 \ OB I�PC 342 0 / /(�J/ /� / � I n �51I65' A•OB� .N 5AR/ / � 9�/ I VRI 26 £N 1M1pBIIMNT ROA� Cn- Pc 341 TI CROSSING \ VDnN \ \ PUB LIC 403 \ 6 0 60 120 180 R90 PG 39W8O Pc P 1S 15091OB1 EASEMENT `\ O EASEMENT ` \ \ 'L Scale: 1"=60' DO 1113 PG 3�8 DA 1 - O 2L POA 1 S4 Reach X 4on Llflk �3S> - Offsite Predev PREDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 2 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 - Onsite Runoff Area=2.860 ac 0.00% Impervious Runoff Depth=1.24" Tc=20.5 min CN=80 Runoff=3.80 cfs 0.294 of Link 2L: POA 1 Inflow=4.56 cfs 0.352 of Primary=4.56 cfs 0.352 of Subcatchment3S: DA 1 - Offsite Runoff Area=0.420 ac 30.95% Impervious Runoff Depth=1.65" Tc=20.5 min CN=86 Runoff=0.76 cfs 0.058 of Total Runoff Area = 3.280 ac Runoff Volume = 0.352 of Average Runoff Depth = 1.29" 96.04% Pervious = 3.150 ac 3.96% Impervious = 0.130 ac Predev PREDEV Type/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 1S: DA 1 - Onsite Runoff = 3.80 cfs @ 12.14 hrs, Volume= 0.294 af, Depth= 1.24" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 2.860 80 >75% Grass cover, Good, HSG D 0.000 98 Unconnected pavement, HSG D 2.860 80 Weighted Average 2.860 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 20.5 Direct Entry, Subcatchment 1S: DA 1 - Onsite Hydrograph I I I j I I L i i I II i I I I I I I I II I I 4 � 3.80 1djJ_� _I_ __'_ i_ `__`__I___I__�'__'__�__`_ `__I___I__ ■Runoff ' I I I I I I I I I I Type Ili 24-hr I-yr I I I I I I I I I I I I 1 RlainfallT2.198 ----J--1--1--L--L--I-- 1--J--1--L--L--L--I-- I-- 3 11 11 11 �RUnbffl AreA=2.860 al, 1 1 1 1 1 1 1 1 1 ROn6ff111 Vg1Lpm,64.294 of kunoff 11Depth-1.1124"'_ 1--1--I- --- 2 , Td=20 .5 tnih LL 1 I I I I I I I I I I I 1 I I I I I I I I I I I /�/� 1 1 1 1 1 1 1 1 1 '"N=Bp 1 1 i 1 1 1 1 1 i 1 1 1 I 1 1 1 I 1 1 1 1 1 ------------------------ 1 1 1 I 1 1 1 1 1 1 1 1 1 1 I 1 1 1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Predev PREDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 4 Summary for Link 2L: POA 1 Inflow Area = 3.280 ac, 3.96% Impervious, Inflow Depth = 1.29" for 1-yr event Inflow = 4.56 cfs @ 12.14 hrs, Volume= 0.352 of Primary = 4.56 cfs @ 12.14 hrs, Volume= 0.352 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph ❑ Inflow ❑ Primary 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Predev PREDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 5 Summary for Subcatchment 3S: DA 1 - Offsite Runoff = 0.76 cfs @ 12.13 hrs, Volume= 0.058 af, Depth= 1.65" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 0.290 80 >75% Grass cover, Good, HSG D 0.130 98 Unconnected pavement, HSG D 0.420 86 Weighted Average 0.290 69.05% Pervious Area 0.130 30.95% Impervious Area 0.130 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 20.5 Direct Entry, I -�I 0.8 0.76 ----I__J__ 0.75 07 O.65 0.6 0.55 I--r 0.5 0.45 0.4 I I I I I p LL 0.35 0.3 I 0.25 0.2 I I I I I 0.15 0.1 0.05 Subcatchment 3S: DA 1 - Offsite Hydrograph I I I I I I I I I I I I I I I I I I I ------=--=--=-----II--frnbffll ��-a2aad- I I I I I I I I I I I I I I I I I u ff ofa 4--050-0 -II-- -- ;-- ----------AunQif lllRe tk>z9s 5 ` _L _I _I _1 I I I I I I I I I I I ITTddI qqI/� III�I �Iy.� I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ______________________________________ I I I I I I I I I I I I I I I I I L. _I__J__1__y__L__I___I__J__y__L__L__I__J__1__y__L__I__ 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ■ Runoff Predev PREDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 6 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 - Onsite Runoff Area=2.860 ac 0.00% Impervious Runoff Depth=3.28" Tc=20.5 min CN=80 Runoff=10.27 cfs 0.782 of Link 2L: POA 1 Inflow=12.02 cfs 0.918 of Primary=12.02 cfs 0.918 of Subcatchment3S: DA 1 - Offsite Runoff Area=0.420 ac 30.95% Impervious Runoff Depth=3.88" Tc=20.5 min CN=86 Runoff=1.76 cfs 0.136 of Total Runoff Area = 3.280 ac Runoff Volume = 0.918 of Average Runoff Depth = 3.36" 96.04% Pervious = 3.150 ac 3.96% Impervious = 0.130 ac Predev PREDEV Type // 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 12/9/2022 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 7 Summary for Subcatchment 1S: DA 1 - Onsite Runoff = 10.27 cfs @ 12.13 hrs, Volume= 0.782 af, Depth= 3.28" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 2.860 80 >75% Grass cover, Good, HSG D 0.000 98 Unconnected pavement, HSG D 2.860 80 Weighted Average 2.860 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 20.5 Direct Entry, 10 27 cfs 10 I I I I 9 8 II 7 II IIII ,. 6 I I I I I 3 M 5 I I I I 4- 3- 2- 8 10 Subcatchment 1S: DA 1 - Onsite Hydrograph -rtYpe MI 241hr 10-y� Rainfall:*." I I I I I I I I I I I I I I I I I I I I I I I I I I I I L -I -- -- unoffl6j h-41' 81�r I I I I I I I I I I I I i I I I I I C _r__I___I__,__ T__ T__ T__ r__ r__I___I T&20 iJ - ill._y� _ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -------------------------------------------------- I I I I I I I I I I I I I I I I I I I I I I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I i I I I I-------------- 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Predev PREDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 8 Summary for Link 2L: POA 1 Inflow Area = 3.280 ac, 3.96% Impervious, Inflow Depth = 3.36" for 10-yr event Inflow = 12.02 cfs @ 12.13 hrs, Volume= 0.918 of Primary = 12.02 cfs @ 12.13 hrs, Volume= 0.918 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph -♦ -f -I -I _� -1- -I -y _J _} F I _J _} -f -I --I -i -h -F -I ■ Inflow 113 12.0c 0Ia�12 --+-anfiawAreii-F a 1-JJ-1IIIIIIII11111111 0 Pdma ry 1Q I I I I ] I-- _I__I__I__I____I__I__ ___ __ _______ p 6LL4 2 _J__J__ I I I I I I I I I I 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Predev PREDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 9 Summary for Subcatchment 3S: DA 1 - Offsite Runoff = 1.76 cfs @ 12.13 hrs, Volume= 0.136 af, Depth= 3.88" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 0.290 80 >75% Grass cover, Good, HSG D 0.130 98 Unconnected pavement, HSG D 0.420 86 Weighted Average 0.290 69.05% Pervious Area 0.130 30.95% Impervious Area 0.130 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 20.5 Direct Entry, t Subcatchment 3S: DA 1 - Offsite Hydrograph 1 1.76 cfs I Type II 24-hr 10-y!r Rainfall=5.44" Runoff Area=0.420 ad Runoff Volume=0.136 of Runoff Depth=3.88" Tc=20.5 min CN=816 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ❑ Runaff Predev PREDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 10 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: DA 1 - Onsite Runoff Area=2.860 ac 0.00% Impervious Runoff Depth=6.49" Tc=20.5 min CN=80 Runoff=19.96 cfs 1.547 of Link 2L: POA 1 Inflow=23.14 cfs 1.800 of Primary=23.14 cfs 1.800 of Subcatchment3S: DA 1 - Offsite Runoff Area=0.420 ac 30.95% Impervious Runoff Depth=7.23" Tc=20.5 min CN=86 Runoff=3.18 cfs 0.253 of Total Runoff Area = 3.280 ac Runoff Volume = 1.800 of Average Runoff Depth = 6.59" 96.04% Pervious = 3.150 ac 3.96% Impervious = 0.130 ac Predev PREDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 11 Summary for Subcatchment 1S: DA 1 - Onsite Runoff = 19.96 cfs @ 12.13 hrs, Volume= 1.547 af, Depth= 6.49" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description 2.860 80 >75% Grass cover, Good, HSG D 0.000 98 Unconnected pavement, HSG D 2.860 80 Weighted Average 2.860 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 20.5 Direct Entry, Subcatchment 1S: DA 1 - Onsite -----;---- ---I- ,- ;- I- ;- 19.9-6 _I___I__J__1__1__y__L__L__I___I__J__�__y__y__L-- ■RunO,F I _ ;--;--_ *- r- 20 19 18 I 17 16 ___1 15 14 13 b 12 3 „ I 0 10 LL I 9 I 6 , I 5 2 8 10 -- - -- - - -- ; 'gyp 11'124-* I 004jr - I I I I I I I I I I I I L L R'Wnf-allT$92"- I I I I I I I I I I I I__J__1__1yw(_1_r_�LL--L__1___I__J__1__1__L_}_—}L(�.__ r 1 ktttto# Deptlt-4G i497 - I 1 1 I I I 0 _1 I I 1 1 I I I I I 1 1 1 I I I 1 1 1 1 N----------------------------------- ----- - I I 1 I I I I I 1 I I I I I 1 I I I I I I 1 I I I I 1 1 1 I I 1 1 1 1 __,__r__r__r__r__r__r__1__r__4__r__r__r__ I I 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Predev PREDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 12 Summary for Link 2L: POA 7 Inflow Area = 3.280 ac, 3.96% Impervious, Inflow Depth = 6.59" for 100-yr event Inflow = 23.14 cfs @ 12.13 hrs, Volume= 1.800 of Primary = 23.14 cfs @ 12.13 hrs, Volume= 1.800 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs I I I I J J I I I - - 23.14 cfs 24 ;- ; 22 I _J _J _L _L I I I I 20 -I _J _A _L I I I I I I I I 16 -1 -- -T -r I I I I M Gu 14 --r-,--T--r O 12 LL i I I I I �Q i � __I_ _ II__I _ I I I I I I I I 8 6 4 Link 2L: POA 1 Hydrograph .Inflow ■Pnmary I _J__L__I__J__J__L__L__I__J__1__L_J__J__1__L__L_J__ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1__r__r__I__1__T__r__r__I__ I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 11 I I 11 I I I I 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Predev PREDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 12/9/2022 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 13 Summary for Subcatchment 3S: DA 1 - Offsite Runoff = 3.18 cfs @ 12.12 hrs, Volume= 0.253 af, Depth= 7.23" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description 0.290 80 >75% Grass cover, Good, HSG D 0.130 98 Unconnected pavement, HSG D 0.420 86 Weighted Average 0.290 69.05% Pervious Area 0.130 30.95% Impervious Area 0.130 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (f /ft) (f /sec) (cfs) 20.5 Direct Entry, 3.1 1 � _ 0 0 2 4 6 8 10 Subcatchment 3S: DA 1 - Mite Hydrograph $� i i i i i i i i i i i i i i i i ■ Runoff -Y 24- r'I00yr R'ainfallT8.92 RUnbff Are.1=0.420 at: Y T--04n�)ffi'iVQ1"rnO,0-25' alf- kunoff e' PO47.237 'Td=20:5 tinil N=8 --r i i r__r__r__r__r i i r__r__r__r__r i i L L 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) 100 ft overland flow 467 ft s. c. flow 00 ft swale Forest Lakes Self Storage Time of Concentration Calculations - Predev 9.0% slope 0.35 C-value 10.8 min 2.6% slope 0.8 fps velocity 9.7 min. height min. 20.5 min. Seelye Chart NEH Figure 15-4 Kirpich Chart 35 30 u Payed 9 z 2S C .0 300 Bare 7 W o 20 w 200 Soil .• Poor W \ Grass F Surface U. AVGfaera ss V • J 0.5 W w 0 0 15 _ 90 \ O 2'0 J w/ / / a BO Dense Gross \ a z F 70 e \� 5.0 z 1— in 60 3 /� 10 ¢ 5 0 `' a 20 a W J 40 U z 0 10 U S 30 9 w z W ! J B 20 7 10 6 OVERLAND FLOW TIME (Sedyc Chart) Source: Oa® Back for Civil Envinem. E.E. Secke Plate 5-1 1.00 090 Spa 0.70 0.60 0.so 0.40 020 020 0.a 0.03 0.02 OAI oms o.. mmommossin111111 uum NMI I ■ii'o'iiiiiiiiii� ■iiili� �11111� 11111111� 11111111� 1111111111� IIIIIIIIII- IIIIIIIIIII� =Ni=f331io ..... 1....11M Cf I����ou�n!n!un :::i11111111�1 ��—� ��� �■■ vEwrlw (rtm) Post -Development Stormwater Management Calculations: Post -Development Drainage Area Map Post -Development HydroCAD Analysis Energy Balance Equation Summary LD-204 Stormwater Inlet Computations LD-229 Storm Drain Design Computations Outlet Protection Calculations FOREST LAKES SELF STORAGE POSTDEV DRAINAGE AREA MAP 4000, i OFFSITE DRAINAGE AREA 3 TO POA 1 (TREATED) DO 4W9 1MP B4-3Y$8 � \ DB 4B 2 PC 153 (I AT) \ P OFFSITE DRAINAGE AREA \ TO POA 1 (UNTREATED) % 2902'59'E 155.50' 21 0'0 \ Fow uax � I \ -'\ E ER. - AY W EC-3 MA"M \ 51].00 \ OEIENllg1 POND szav4•n•w \Bo'rtw slaw&W I 17 �O\ I r \ \ RI ROA J \ ,. sa•54'Da^x 54.z5' —> ONSITE DRAIN TO POA 1 (UNTI \ 1 DAUTO' PARTS \ OFFSITE DRAINAGE AREA Drainage Area 1: TO POA 1 (TREATED) Total Area = 3.78 ac =� E / Onsite Area = 3.10 ac l P 32-37CI - MEN BMARYR. Managed Turf = 1.40 ac (HSG D) MERCE DB 3522 PRD 101 OR W22 PC,94(PUT) r Impervious = 1.70 ac (HSG D) Offsite Area = 0.68 ac Managed Turf = 0.55 ac (HSG D) 1 Impervious = 0.13 ac (HSG D) Time of Concentration = 5.0 X22 \ F\ 22 i RD \ NP 4084-3 \ I 2 PD-x/P dA-zAN MED IRD sAreNEresHIP \ \ I I \ DB 1169 PC N] \ I ONSITE DRAINAGE AREA OFFSITE DRAINAGE AREA TO POA 1 (TREATED) ( I TO POA 1 (TREATED) \ \ I 1 WP 40B4-4 \ I 1 O I N N/F Jq-ZAN IIMIIED P.VtNEreSHIP Z.M. PD-BC DB 1144 PC 382 J m B \ — ,GE AREA 0 2EATED) t 60 0 Scale: 1`'� 60 120 N 180 DA 1 (is Onsite In DETE POA 1 S4 Reach Aon Llnk e d 5S A 1 - Offsite In -Managed Postdev POSTDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 2 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: DA 1 - Onsite Managed Runoff Area=2.660 ac 62.03% Impervious Runoff Depth=2.05" Tc=5.0 min CN=91 Runoff=9.64 cfs 0.455 of Link 2L: PDA 1 Inflow=2.11 cfs 0.585 of Primary=2.11 cfs 0.585 of Pond 3P: DETENTION POND Peak Elev=515.15' Storage=13,267 cf Inflow=10.58 cfs 0.498 of Outflow=0.29 cfs 0.498 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.300 ac 40.00% Impervious Runoff Depth=1.72" Tc=5.0 min CN=87 Runoff=0.94 cfs 0.043 of Subcatchment4S: DA 1 - Onsite Runoff Area=0.440 ac 11.36% Impervious Runoff Depth=1.30" Tc=5.0 min UI Adjusted CN=81 Runoff=1.06 cfs 0.048 of Subcatchment5S: DA 1 - Offsite Runoff Area=0.380 ac 2.63% Impervious Runoff Depth=1.24" Tc=5.0 min CN=80 Runoff=0.87 cfs 0.039 of Total Runoff Area = 3.780 ac Runoff Volume = 0.585 of Average Runoff Depth = 1.86" 51.59% Pervious = 1.950 ac 48.41% Impervious = 1.830 ac Postdev POSTDEV Type/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 9.64 cfs @ 11.96 hrs, Volume= 0.455 af, Depth= 2.05" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 1.650 98 Unconnected pavement, HSG D 1.010 80 >75% Grass cover, Good, HSG D 2.660 91 Weighted Average 1.010 37.97% Pervious Area 1.650 62.03% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet)(ft/ft)(f /sec) (cfs) 5.0 Direct Entry, 10 I I I I I I --I--,- 9.6 I I I 9 I I I I I I I I I I I I I ----------- I I I I I I 6 v I I I I I I I I LL I I I I 4 I I I I I I I I 3 I I I I I I I I 2 I I I I I I I I 0 2 4 6 8 Subcatchment 1S: DA 1 - Onsite Managed Hydrograph I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I--I--I--- Runoff IT a IF 2 0r J- I I I I I I I I I I I I I I I I I _I Qlatnf iiT i.\lV�, - I I I I I I I I I I I I I J-- - nbffAke�=2-660ai: - 1 I I RunOff'�V_g1v1 �e_=_0.4%c1f__ ku noff-111 Depth=F2.1057_ - I I 1 1 I I I I I 1 1 1 I I Ir/�, 1 1Ln 1 1 1 T&5.0 tnih 1 1 1 J__1__L__L__ 4N=91 1 1 1 1 1 1 I I 1 1 1 I I I I 1 1 1 I I I 1 1 I I 1 1 1 I I I I 1 1 1 I I I 1 1 I I 1 1 1 I I I I 1 1 1 I I I 1 1 1 1 1 I I I I 1 1 1 I I I 1 1 i 1 1 I I I I 1 1 1 I I I 1 1 I I I I 1 1 1 I I I 1 1 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 4 Summary for Link 2L: POA 7 Inflow Area = 3.780 ac, 48.41% Impervious, Inflow Depth = 1.86" for 1-yr event Inflow = 2.11 cfs @ 11.97 hrs, Volume= 0.585 of Primary = 2.11 cfs @ 11.97 hrs, Volume= 0.585 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph ■ Inflow ■ Primary Time (hours) Postdev POSTDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here) Printed 2/13/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 5 Summary for Pond 313: DETENTION POND Inflow Area = 2.960 ac, 59.80% Impervious, Inflow Depth = 2.02" for 1-yr event Inflow = 10.58 cfs @ 11.96 hrs, Volume= 0.498 of Outflow = 0.29 cfs @ 14.21 hrs, Volume= 0.498 af, Atten= 97%, Lag= 135.1 min Primary = 0.29 cfs @ 14.21 hrs, Volume= 0.498 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 515.15' @ 14.21 hrs Surf.Area= 7,175 sf Storage= 13,267 cf Plug -Flow detention time= 648.6 min calculated for 0.498 of (100% of inflow) Center -of -Mass det. time= 648.6 min ( 1,451.2 - 802.6 ) Volume Invert Avail.Storage Storage Description #1 513.00' 37,810 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 513.00 5,223 0 0 514.00 6,088 5,656 5,656 516.00 7,982 14,070 19,726 518.00 10,102 18,084 37,810 Device Routing Invert Outlet Devices #1 Primary 512.00' 15.0" Round 15" HDPE Out L= 94.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.00' / 509.23' S= 0.0295 T Cc= 0.900 n= 0.010 PVC, smooth interior #2 Device 1 516.00' 48.0" Horiz. 48" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 515.00' 6.0" Vert. 6" Control Orifice C= 0.600 #4 Primary 517.00' 18.0' long x 47.0' breadth 18' Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 #5 Device 1 512.50' 4.0" Round 4" Perf. Underdrain L= 69.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.50' / 512.33' S= 0.0025 T Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior Primary OutFlow Max=0.29 cfs @ 14.21 hrs HW=515.15' (Free Discharge) 1=15" HDPE Out (Passes 0.29 cfs of 7.41 cfs potential flow) 2=48' Standpipe ( Controls 0.00 cfs) 3=6" Control Orifice (Orifice Controls 0.06 cfs @ 1.31 fps) =4" Perf. Underdrain (Barrel Controls 0.22 cfs @ 2.58 fps) =18' Emergency Spillway ( Controls 0.00 cfs) POSTDEV Prepared by {enter your company name here} W I 10.58 I � I I I I I I I I I I 9 __I__1__1__r__I_ I I I I I I I I I I I I I I I I I I I I 5 I I I I I ----- I --I --I I I I I I I I I I I I I 2 I I I I Postdev Type/1 24-hr 1-yr Rainfall=2.98" Printed 2/13/2023 Pond 3P: DETENTION POND Hydrograph I I I --I-- I I I I I I 1'I,nfilow'I,k�ai2 9$fi111a I I I I I I I I StOrag0=11267 d I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1 1 1 I I 1 1 I I 1 1 I I I 1 1 I i I I I I I I I I I I I I I I I I I I I I I I I I 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (crs) ■ Inflow ■ Primary ❑ Primary POSTDEV Prepared by {enter your company name here} Postdev Type/1 24-hr 1-yr Rainfall=2.98" Printed 2/13/2023 Pond 3P: DETENTION POND Stage -Area -Storage Surface/Horizontal/Wetted Area (sq-ft) 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 11 518 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 517 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I T 516 I I I I I I I I I I I I _1_J I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I C I I I I I I I I I I I I I W I I I I I I I I I I I I I I I I I I I I I I I I I I W 515 I I I I I I I I I I I I I I I I I I I I I I I I I I I 514 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Custom Stage Data 513 0 5,000 10,000 15,000 20,000 25,000 30,000 nboo Storage (cubic %M) ■ Surface ■ Storage Postdev POSTDEV Type/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 8 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 0.94 cfs @ 11.96 hrs, Volume= 0.043 af, Depth= 1.72" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 0.120 98 Unconnected pavement, HSG D 0.180 80 >75% Grass cover, Good, HSG D 0.300 87 Weighted Average 0.180 60.00% Pervious Area 0.120 40.00% Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: DA 1 - Offsite Managed Hydrograph - - - - - ■ Runoff ITY, pe I I; 2-hr 'M -Yr R'ainfallT2.�98 Rtrnbff Ares=0.300 at, tt#n4ff', Vgkjt me=O.p4$ of kulnoff Del pth41.72 f&5.0 Milli N=8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 9 Summary for Subcatchment 4S: DA 1 - Orl Un-Managed Runoff = 1.06 cfs @ 11.96 hrs, Volume= 0.048 af, Depth= 1.30" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 0.050 98 Unconnected pavement, HSG D 0.390 80 >75% Grass cover, Good, HSG D 0.440 82 Weighted Average, UI Adjusted CN = 81 0.390 88.64% Pervious Area 0.050 11.36% Impervious Area 0.050 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: DA 1 - Onsite Un-Managed Hydrograph 1.06 cfs ❑ RunoH -Type II 24-hr 1-y,r Rainfall=2.98" Runoff Area=0.440 ad Runoff Volume=0.048 of Runoff Depth=1.30 LL Tc=5.0 milli UI Adjusted CN=81 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 10 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 0.87 cfs @ 11.96 hrs, Volume= 0.039 af, Depth= 1.24" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.98" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG D 0.370 80 >75% Grass cover, Good, HSG D 0.380 80 Weighted Average 0.370 97.37% Pervious Area 0.010 2.63% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 5S: DA 1 - Offsite Un-Managed 0.95 __'__J__ 0.8 09 0.85 08 ' 0.75 07 O.65 0.6 0.55 -----T--r ... 05 0 0.45 '_ '_ LL _ -r-1 -T -T -r 04 __i_ 0.35 0.3 0.25 02 0.15 ' n ne Hydrograph i __r_ ,__T__T__r__,___,__T__T__r Y-P .y;Ill i _T1 __T__T__r__r__i__T' __T__r__rRainf�rr�298�'_ '__�_____ r`_,_//rI�� 11,,immi�� T■■��- arrS Ya/rM�-�_T�-1 3 _cif inoff-r--T--r--r--r--r-T-- i � u-e t 1 4 -1 -T -T -r -I -T -T -T r Tc�S.ntM� --i- - ON:FBO i-�--r-r--r--r--r-T__T--r--r--r--r-r --i- i-�--T--r--r--r--r-T--T--r--r--r--i--T--r--r--r- iT__T__r__r_ i- i_---- -- ---- i-------------L--�-- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ■ Runoff Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 11 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: DA 1 - Onsite Managed Runoff Area=2.660 ac 62.03% Impervious Runoff Depth=4.41" Tc=5.0 min CN=91 Runoff=19.70 cfs 0.978 of Link 2L: PDA 1 Inflow=11.28 cfs 1.305 of Primary=11.28 cfs 1.305 of Pond 3P: DETENTION POND Peak Elev=516.33' Storage=22,444 cf Inflow=21.78 cfs 1.077 of Outflow=8.66 cfs 1.077 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.300 ac 40.00% Impervious Runoff Depth=3.98" Tc=5.0 min CN=87 Runoff=2.08 cfs 0.100 of Subcatchment4S: DA 1 - Onsite Runoff Area=0.440 ac 11.36% Impervious Runoff Depth=3.38" Tc=5.0 min UI Adjusted CN=81 Runoff=2.67 cfs 0.124 of Subcatchment5S: DA 1 - Offsite Runoff Area=0.380 ac 2.63% Impervious Runoff Depth=3.28" Tc=5.0 min CN=80 Runoff=2.25 cfs 0.104 of Total Runoff Area = 3.780 ac Runoff Volume = 1.305 of Average Runoff Depth = 4.14" 51.59% Pervious = 1.950 ac 48.41% Impervious = 1.830 ac Postdev POSTDEV Type // 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 12 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 19.70 cfs @ 11.96 hrs, Volume= 0.978 af, Depth= 4.41" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 1.650 98 Unconnected pavement, HSG D 1.010 80 >75% Grass cover, Good, HSG D 2.660 91 Weighted Average 1.010 37.97% Pervious Area 1.650 62.03% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, 22 2, I I I 20 -I 19 - I---I--Y--�--Y 18 17 16 15 14 13 __I_ 12 ' 10 _ _I -I -r -1 -T LL I $ i 6 - I---I--Y--Y--Y 5 4 2 Subcatchment 1S: DA 1 - Onsite Managed Hydrograph I I I I I I I I I I I I I I I I I I __ __ __r__r__I__ �__ �__r__r__r__r__ - �__]__r__r_- ■Runoff 0cfs JI ; F -----'--T- - -- --------'I --Y' t t . . *XRe p41h.0[-yr AIrf Rla'�fatC�5i44" R' 1 1 T I I I I I I I I I I I I I I I I I _ 0nbfF _ free_=2_.66.0 _ab- jRt�rtpffrt/ptllrrre=e:� itwf -; --; _r _I _I _y I 1 1 -' - ' -T 5.0-hltw- I I I I 1 I I I I I I I I I I I I I _F _I y _y _{ _{ _} _ _-y_-y_-y_-r_-r_-r_-1__-1_- - L--- ----L--J--J--J--y--L--I---I--J--J--J--T--J--I--- I I I I 1 I I I I I I 1 I I I I I _4 _L 1 r__I___I__y__Y__Y_____r__r__I__y_____Y__t__r__ 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 13 Summary for Link 2L: POA 1 Inflow Area = 3.780 ac, 48.41 % Impervious, Inflow Depth > 4.14" for 10-yr event Inflow = 11.28 cfs @ 12.04 hrs, Volume= 1.305 of Primary = 11.28 cfs @ 12.04 hrs, Volume= 1.305 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph --r- --i-- __- I ---i--i----i--r--r--r----r--r- -r------r--r--r- MInIm I I ■Primary 12 , , , 11.28 I - � -- cfs low -- - -- - �nf /Y__-' -_�-- I I I I I - 7 0 ac i•ea-3. I I I I I I I I I I i I I i I I I I I I I I I I I I I I I I I I I I I I I I I I I I 9 , I I I I I I I I I I I I I I I I I , I I I I I I I I I I I I I I I I I S 7 , i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 6 , 0 , I I I I I I I I I I I I I I I I I I I I I LL , 5 _L I I I I I I I I I I I I I I I I I I I I I 4 , I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3 , I ____ J_, I - I I �__J____y__ _I-- I I I I I I I I I I I I I 2 , I I -I _� I I I I I I I I I I I I I I 1 -F -I -y -♦ -F -I -y -♦ -F -I- -I I I I I I I I I I I Time (hours) Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 14 Summary for Pond 313: DETENTION POND Inflow Area = 2.960 ac, 59.80% Impervious, Inflow Depth = 4.37" for 10-yr event Inflow = 21.78 cfs @ 11.96 hrs, Volume= 1.077 of Outflow = 8.66 cfs @ 12.06 hrs, Volume= 1.077 af, Atten= 60%, Lag= 6.3 min Primary = 8.66 cfs @ 12.06 hrs, Volume= 1.077 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 516.33' @ 12.06 hrs Surf.Area= 8,335 sf Storage= 22,444 cf Plug -Flow detention time= 403.5 min calculated for 1.076 of (100% of inflow) Center -of -Mass det. time= 404.0 min ( 1,185.1 - 781.2 ) Volume Invert Avail.Storage Storage Description #1 513.00' 37,810 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 513.00 5,223 0 0 514.00 6,088 5,656 5,656 516.00 7,982 14,070 19,726 518.00 10,102 18,084 37,810 Device Routing Invert Outlet Devices #1 Primary 512.00' 15.0" Round 15" HDPE Out L= 94.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.00' / 509.23' S= 0.0295 T Cc= 0.900 n= 0.010 PVC, smooth interior #2 Device 1 516.00' 48.0" Horiz. 48" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 515.00' 6.0" Vert. 6" Control Orifice C= 0.600 #4 Primary 517.00' 18.0' long x 47.0' breadth 18' Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 #5 Device 1 512.50' 4.0" Round 4" Perf. Underdrain L= 69.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.50' / 512.33' S= 0.0025 T Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior Primary OutFlow Max=8.98 cfs @ 12.06 hrs HW=516.33' (Free Discharge) 1=15" HDPE Out (Inlet Controls 8.98 cfs @ 7.32 fps) 2=48" Standpipe (Passes < 7.87 cfs potential flow) 3=6" Control Orifice (Passes < 0.98 cfs potential flow) =4" Perf. Underdrain (Passes < 0.27 cfs potential flow) =18' Emergency Spillway ( Controls 0.00 cfs) POSTDEV Prepared by {enter your company name here} Postdev Type // 24-hr 10-yr Rainfall=5.44" Printed 2/13/2023 Pond 3P: DETENTION POND Hydrograph I I I ----Y--T-- -*----------T--r----Tr------Yrr--I-- ---J- 21.78 cfs } r I I 23 22 -_-_ -__--___--IIIII11 21 20 i 19 __-___- y1Yr11TIII� ---__-- J1Y�J,II1 18 71 17 15 15 __I__J a 14 13 J__1_ 3 12 10 8.66 cfs 9 7 J J 5- 4 W }-_a;n_fl_ow_ tAreAA2.V6Qa__' I I I I I I I I _y J-------------- I --J--L----J--J--L--L--I Q�aMw= tr-----Lc, _ I I I I I I I I I I Y I I -I -I I -I -I -I -I -I -I -I I I I I I I I I I I I I I I I I I __1__L__L_I__ I I I -Y -, -T -Y -I -, -T -Y -I -Y -, -Y -Y -I I I I I I I I I I I I I I I I I I I I - - _ I I 1 I I 1 I I I 1 1 1 I I I I I 1 1 y -} -I -Y -Y -♦ -F -I Y -h -F -I �11 1 I 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (cfs) ■ Inflow ■ Primary ❑ Primary Postdev POSTDEV Type // 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 16 Pond 3P: DETENTION POND Stage -Area -Storage Surface/Horizontal/wetted Area (sq-ft) 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 ■Surface ■ Storage I I I I I I I I I I I I I I 518 I I I I I I I I I I I I I I I I I I I I I I I I 1 12 I 1 1 1 I I 1 1 I 1 I 1 1 1 I I 1 1 1 I 1 I 1 1 1 I I 1 I 1 1 1 1 1 1 1 1 1 517 I 1 I I 1 1 1 I I I 1 1 1 1 1 1 1 1 1 _1_1 _1_J _I I I I I I I I I I I I I I I I I I I I I I I I I I I I I T 516 1 1 1 1 1 1 I 1 I I I 1 1 I 1 1 I I I 1 1 I 1 I I I 1 I 1 1 I I I 1 1 C I 1 I I I 1 I 1 1 I I I 1 1 W I I I I I I I I I I I I I I I I I I I I I I I I I I I I W 515 I I I I I 1 1 I 1 1 I I I 1 1 I I I I 1 1 I 1 1 I I I 1 1 1 1 1 1 1 1 _____�_�_ _r___r_�______r_____r__I r_7______I______r_7____1 I I I I 1 1 I 1 I I I 1 1 1 1 1 1 1 1 1 1 514 1 1 1 1 I 1 1 I I I 1 1 1 1 1 I I I 1 1 I I I 1 1 Custom Stage Data 513 0 5,000 10,000 15,000 20,000 25,000 30,000 35,Ooo Storage (cubic %M) Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 17 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 2.08 cfs @ 11.96 hrs, Volume= 0.100 af, Depth= 3.98" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 0.120 98 Unconnected pavement, HSG D 0.180 80 >75% Grass cover, Good, HSG D 0.300 87 Weighted Average 0.180 60.00% Pervious Area 0.120 40.00% Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: DA 1 - Offsite Managed Hydrograph ❑ Runoff 2.08 cfs Type II 24-hr 10-yr —0 Rainfall=5.44" Runoff Area=0.300 ac Runoff Volume=0.100 of LL ,� I Runoff Depth=3.98i" Tc=5.0 milli CN=87 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 18 Summary for Subcatchment 4S: DA 1 - Orl Un-Managed Runoff = 2.67 cfs @ 11.96 hrs, Volume= 0.124 af, Depth= 3.38" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 0.050 98 Unconnected pavement, HSG D 0.390 80 >75% Grass cover, Good, HSG D 0.440 82 Weighted Average, UI Adjusted CN = 81 0.390 88.64% Pervious Area 0.050 11.36% Impervious Area 0.050 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: DA 1 - Onsite Un-Managed Hydrograph 2.67 cfs Type II 24-hr 10-y!r Rainfall=5.44" Runoff Area=0.440 at 2 Runoff Volume=0.124 of Runoff Depth=3.38" Tc=5.0 milk UI Adjusted CN=81 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ❑ Runaff Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 19 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 2.25 cfs @ 11.96 hrs, Volume= 0.104 af, Depth= 3.28" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.44" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG D 0.370 80 >75% Grass cover, Good, HSG D 0.380 80 Weighted Average 0.370 97.37% Pervious Area 0.010 2.63% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 5S: DA 1 - Offsite Un-Managed Hydrograph ❑ Runoff 2.25 cfs Type II 24-hr 10-yr 2 Rainfall=5.44" Runoff Area=0.380 ac Runoff Volume=0.104 of Runoff Depth=3.28" LL Tc=5.0 min CN=80 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 20 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: DA 1 - Onsite Managed Runoff Area=2.660 ac 62.03% Impervious Runoff Depth=5.63" Tc=5.0 min CN=91 Runoff=24.75 cfs 1.249 of Link 2L: PDA 1 Inflow=15.69 cfs 1.683 of Primary=15.69 cfs 1.683 of Pond 3P: DETENTION POND Peak Elev=516.91' Storage=27,435 cf Inflow=27.41 cfs 1.378 of Outflow=9.66 cfs 1.378 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.300 ac 40.00% Impervious Runoff Depth=5.18" Tc=5.0 min CN=87 Runoff=2.66 cfs 0.130 of Subcatchment4S: DA 1 - Onsite Runoff Area=0.440 ac 11.36% Impervious Runoff Depth=4.52" Tc=5.0 min UI Adjusted CN=81 Runoff=3.52 cfs 0.166 of Subcatchment5S: DA 1 - Offsite Runoff Area=0.380 ac 2.63% Impervious Runoff Depth=4.41" Tc=5.0 min CN=80 Runoff=2.98 cfs 0.140 of Total Runoff Area = 3.780 ac Runoff Volume = 1.684 of Average Runoff Depth = 5.34" 51.59% Pervious = 1.950 ac 48.41% Impervious = 1.830 ac Postdev POSTDEV Type /124-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 21 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 24.75 cfs @ 11.96 hrs, Volume= 1.249 af, Depth= 5.63" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.69" Area (ac) CN Description 1.650 98 Unconnected pavement, HSG D 1.010 80 >75% Grass cover, Good, HSG D 2.660 91 Weighted Average 1.010 37.97% Pervious Area 1.650 62.03% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, Subcatchment 1S: DA 1 - Onsite Managed 26 I I I I 24.75 24 22 I I I I I 20 I I I I I ----------- 18 I I I I I 14 3 M 12 I I I I I ,Q I I I I I ----------- I I I I I I I I 4 Hydrograph I I I I I I I I I I I I I I I I I __I___I__J__i__i__i__i__L__I-__I__i__i__i__i__L_- ■Runoff fS I I I I I I I I I I I I I I I I --i--.--,--- VpI-e4i - ^i11'2 -�r ' I I I I I I I I I I I , I I I I I I I I I I 1 Rainfal1T6.6911111 1 _JI__J____1 - - - ffAke- nb266Dat I I I k noffbeptlr5� 3k` 1 I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I N=gq I I I I 1 I I I I I I 1 I I -------------------------------------------------- I I I I 1 I I I I I I 1 I I I I I I I I I 1 I I I I I I 1 I I I I I I I I I I I I I I I I 1 I I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I --r-----*--r--r-- 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type /124-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 22 Summary for Link 2L: POA 1 Inflow Area = 3.780 ac, 48.41 % Impervious, Inflow Depth > 5.34" for 25-yr event Inflow = 15.69 cfs @ 11.97 hrs, Volume= 1.683 of Primary = 15.69 cfs @ 11.97 hrs, Volume= 1.683 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph ■ Inflow / ■ Primary 17 15.69 cfs 1nfil_ 11V1/L__1__J o. 15 14 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , r 1 1 1 1 1 1 1 1 r 1 1 1 1 1 1 13 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 _1__ 12 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 --r-r-r-r -�__r__r-�__�__r__r--r-l--r--r--1--1--r--r--r--1-_ 11 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , , __1__1__1__r_ _7__r__1__y__1__r__r__1__1__r__r__1__y__1__r__r__1__ 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 g 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 G g 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 LL , - 1--J--1--L- -,--`--'--J--J--1--L--1--J--1--L- I--J--1--L--`-I-- 7 I__ I__I I__ I__I 6 __ __I _ 1 1 1 1 1 1 1 1 _ __I___I__ __I___I___I__ __I___I___I__ __I___I__ 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 T 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 , __1__l__T__r_ 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 __1 1__r Time (hours) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here) Printed 2/13/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 23 Summary for Pond 313: DETENTION POND Inflow Area = 2.960 ac, 59.80% Impervious, Inflow Depth = 5.59" for 25-yr event Inflow = 27.41 cfs @ 11.96 hrs, Volume= 1.378 of Outflow = 9.66 cfs @ 12.07 hrs, Volume= 1.378 af, Atten= 65%, Lag= 6.6 min Primary = 9.66 cfs @ 12.07 hrs, Volume= 1.378 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 516.91' @ 12.07 hrs Surf.Area= 8,947 sf Storage= 27,435 cf Plug -Flow detention time= 337.2 min calculated for 1.378 of (100% of inflow) Center -of -Mass det. time= 336.9 min ( 1,111.6 - 774.6 ) Volume Invert Avail.Storage Storage Description #1 513.00' 37,810 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 513.00 5,223 0 0 514.00 6,088 5,656 5,656 516.00 7,982 14,070 19,726 518.00 10,102 18,084 37,810 Device Routing Invert Outlet Devices #1 Primary 512.00' 15.0" Round 15" HDPE Out L= 94.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.00' / 509.23' S= 0.0295 T Cc= 0.900 n= 0.010 PVC, smooth interior #2 Device 1 516.00' 48.0" Horiz. 48" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 515.00' 6.0" Vert. 6" Control Orifice C= 0.600 #4 Primary 517.00' 18.0' long x 47.0' breadth 18' Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 #5 Device 1 512.50' 4.0" Round 4" Perf. Underdrain L= 69.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.50' / 512.33' S= 0.0025 T Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior Primary OutFlow Max=9.65 cfs @ 12.07 hrs HW=516.91' (Free Discharge) 1=15" HDPE Out (Inlet Controls 9.65 cfs @ 7.86 fps) 2=48" Standpipe (Passes < 35.41 cfs potential flow) 3=6" Control Orifice (Passes < 1.22 cfs potential flow) =4" Perf. Underdrain (Passes < 0.29 cfs potential flow) =18' Emergency Spillway ( Controls 0.00 cfs) Postdev POSTDEV Type 1124-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 24 Pond 3P: DETENTION POND Hydrograph , ■Inflow 30 -27_ -.4�_ 1 _ S.-_-_- ■Primary =296a-- - , ___'i1IIII -_rLIIII --_IIIIII --_YJIIII --_yJIIII --_,r1IIII 1_IIrILInfi_IIII'II lS_,tJwII o_'r1III k l26282a 22 rmrII IIII =2YII TTII 43rII 5[rII cf 20 18 _,_,_r__rr,__r_r_,__r__rIIIII , I I I I I I I I I I I I I I I I I I I I I I cf 16 I I I I I I I I I I I I I I I I I I I I I I , p 14 I I I I I I I I I I I I I I I I I I I I I I LL I I I I I I I I I I I I I I I I I I I I I I 12 10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I , 8 , _L _I __1 _L _I _J _1 _L _L _I 6 J , I I 4 I -r -I I -r -I -, -1 -r -r -I I I I W 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (crs) ❑ Primary Postdev POSTDEV Type /124-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 25 Pond 3P: DETENTION POND Stage -Area -Storage Surface/Horizontal/wetted Area (sq-ft) 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 ■Surface ■ Storage I I I I I I I I I I I I I I 518 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 517 I I I I I I I I I I I I _1_1 _1_J _I I I I I I I I I I I I I I I I I I I I I I I I I I I I I T 516 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I C I I I I I I I I I I I I I I W I I I I I I I I I I I I I I I I I I I I I I I I I I I I W 515 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I _____�_�_ _r___r_�______r_____r__I r_r______I______r_r____I I I I I I I I I I I I I I 514 I I I I I I I I I I I I I I I I I I I I I I I I I Custom Stage Data 513 0 5,000 10,000 15,000 20,000 25,000 30,000 35,Ooo Storage (cubic %M) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 26 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 2.66 cfs @ 11.96 hrs, Volume= 0.130 af, Depth= 5.18" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.69" Area (ac) CN Description 0.120 98 Unconnected pavement, HSG D 0.180 80 >75% Grass cover, Good, HSG D 0.300 87 Weighted Average 0.180 60.00% Pervious Area 0.120 40.00% Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: DA 1 - Offsite Managed Hydrograph 2.66 cfs Type II 24-hr 25-y!r Rainfall=6.69" Runoff Area=0.300 at 2 Runoff Volume=0.130 of Runoff Depth=5.187 Tc=5.0 milk CN=87 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ❑ Runaff Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 27 Summary for Subcatchment 4S: DA 1 - Orl Un-Managed Runoff = 3.52 cfs @ 11.96 hrs, Volume= 0.166 af, Depth= 4.52" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.69" Area (ac) CN Description 0.050 98 Unconnected pavement, HSG D 0.390 80 >75% Grass cover, Good, HSG D 0.440 82 Weighted Average, UI Adjusted CN = 81 0.390 88.64% Pervious Area 0.050 11.36% Impervious Area 0.050 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: DA 1 - Onsite Un-Managed Hydrograph 3.52 cfs Type II 24-hr 25-yr Rainfall=6.69" Runoff Area=0.440 ac Runoff Volume=0.166 of Runoff Depth=4.52" Tc=5.0 milk UI Adjusted CN=81 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) ❑ Runoff Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 28 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 2.98 cfs @ 11.96 hrs, Volume= 0.140 af, Depth= 4.41" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.69" Area (ac) CN Description 0.010 98 Unconnected pavement, HSG D 0.370 80 >75% Grass cover, Good, HSG D 0.380 80 Weighted Average 0.370 97.37% Pervious Area 0.010 2.63% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 5S: DA 1 - Offsite Un-Managed Hydrograph 1 2.98 cfs I ❑ Runoff Type II 24-hr 25-y!r Rainfall=6.69" Run6ff'Alrea=0.380 at Runoff', VQ1ume=D.-140-c0- Runoff Depth=4.417 Tc=5.0 Min CN=80 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 29 Time span=0.00-48.00 hrs, dt=0.03 hrs, 1601 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method SubcatchmentlS: DA 1 - Onsite Managed Runoff Area=2.660 ac 62.03% Impervious Runoff Depth=7.83" Tc=5.0 min CN=91 Runoff=33.68 cfs 1.737 of Link 2L: PDA 1 Inflow=34.27 cfs 2.367 of Primary=34.27 cfs 2.367 of Pond 3P: DETENTION POND Peak Elev=517.49' Storage=32,779 cf Inflow=37.36 cfs 1.920 of Outflow=26.87 cfs 1.919 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.300 ac 40.00% Impervious Runoff Depth=7.35" Tc=5.0 min CN=87 Runoff=3.68 cfs 0.184 of Subcatchment4S: DA 1 - Onsite Runoff Area=0.440 ac 11.36% Impervious Runoff Depth=6.61" Tc=5.0 min UI Adjusted CN=81 Runoff=5.04 cfs 0.243 of Subcatchment5S: DA 1 - Offsite Runoff Area=0.380 ac 2.63% Impervious Runoff Depth=6.49" Tc=5.0 min CN=80 Runoff=4.30 cfs 0.206 of Total Runoff Area = 3.780 ac Runoff Volume = 2.368 of Average Runoff Depth = 7.52" 51.59% Pervious = 1.950 ac 48.41% Impervious = 1.830 ac Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 30 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 33.68 cfs @ 11.96 hrs, Volume= 1.737 af, Depth= 7.83" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description 1.650 98 Unconnected pavement, HSG D 1.010 80 >75% Grass cover, Good, HSG D 2.660 91 Weighted Average 1.010 37.97% Pervious Area 1.650 62.03% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, 36 I I I I I __i __i___1_ 33.E 34 32 - r--r-r--�--, 30 28 26 24 _ 22 18 18 14 12 16 g I I I I p' 1 Subcatchment 1S: DA 1 - Onsite Managed Hydrograph I I I I I I I I I I I I I I I I I I __ _____i __� __1__r__ �__r__r__r__r__r__1___�__ �__r__r__r_- ■Runoff i8 cfs I I I I I I I I I I I I I I I I ;1 ,Typifll,�=1�r'IOI=y� --r--r--I---I--,--I-1--T--r--r--I-Q-II--�,1�-*r-�,-1-�T--rQ-//fir-- -I Ratnfal .921' - I I I I I I I I I I I I I I I I I ROKOfF-AFe =2.66II ae - __y__y__r__r__ r__1___1__y__y__t__r__r__ -"i #I-.J31-4f- -- ----kunai#111Q�7 3�'_- L1 L 1 L 1 epthTz*5 .0_ -tn_ ie I I I I I I I I I I I I CtN �i4 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ______________________________________________ I I I I I I I I I I I I I I I I I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 31 Summary for Link 2L: POA 1 Inflow Area = 3.780 ac, 48.41 % Impervious, Inflow Depth > 7.51" for 100-yr event Inflow = 34.27 cfs @ 12.01 hrs, Volume= 2.367 of Primary = 34.27 cfs @ 12.01 hrs, Volume= 2.367 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Link 2L: POA 1 Hydrograph -�I --~--+--F -I -y i -+ -F -I - ❑Inflow 38 -I -y tI�__�__�__r_-I r--I--�__+__r__r__I__ ❑ Primary ,' 34.27 cfs ----}-iI,InfloWArl eOF of - 336 ;,78G 32 __I__1__7__r__r__I__ 30 28 _I_ 26 24 i• i __I__1__1__r_ __7__r I I 1--r I I I T--r I I 1--r I I M 22 V 20 I I I I I I I I I I I I I I I I I I I I I is ------------ LL 16 14 L__I__J__J__1__L__I__J__1__L_J__J__1__L__L_J__ 12 I _L _I _J _J _L _L _I _J _1 _L_J _J _1 _L _L_J 10 ' __J__L__L__I__ J__ 1__ L__I__J__ 1__ L__L__I__ 6 ' �' _I _J _1 _L _J _L _I _J _J _1 _L _I _J _1 _L _I _J _1 _L _L _I 6 ' Time (hours) Postdev POSTDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here) Printed 2/13/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 32 Summary for Pond 313: DETENTION POND Inflow Area = 2.960 ac, 59.80% Impervious, Inflow Depth = 7.78" for 100-yr event Inflow = 37.36 cfs @ 11.96 hrs, Volume= 1.920 of Outflow = 26.87 cfs @ 12.02 hrs, Volume= 1.919 af, Atten= 28%, Lag= 3.6 min Primary = 26.87 cfs @ 12.02 hrs, Volume= 1.919 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 517.49' @ 12.02 hrs Surf.Area= 9,560 sf Storage= 32,779 cf Plug -Flow detention time= 265.9 min calculated for 1.919 of (100% of inflow) Center -of -Mass det. time= 265.5 min ( 1,031.7 - 766.2 ) Volume Invert Avail.Storage Storage Description #1 513.00' 37,810 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 513.00 5,223 0 0 514.00 6,088 5,656 5,656 516.00 7,982 14,070 19,726 518.00 10,102 18,084 37,810 Device Routing Invert Outlet Devices #1 Primary 512.00' 15.0" Round 15" HDPE Out L= 94.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.00' / 509.23' S= 0.0295 T Cc= 0.900 n= 0.010 PVC, smooth interior #2 Device 1 516.00' 48.0" Horiz. 48" Standpipe C= 0.600 Limited to weir flow at low heads #3 Device 1 515.00' 6.0" Vert. 6" Control Orifice C= 0.600 #4 Primary 517.00' 18.0' long x 47.0' breadth 18' Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63 #5 Device 1 512.50' 4.0" Round 4" Perf. Underdrain L= 69.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 512.50' / 512.33' S= 0.0025 T Cc= 0.900 n= 0.020 Corrugated PE, corrugated interior Primary OutFlow Max=26.37 cfs @ 12.02 hrs HW=517.48' (Free Discharge) 1=15" HDPE Out (Inlet Controls 10.28 cfs @ 8.37 fps) 2=48" Standpipe (Passes < 73.57 cfs potential flow) 3=6" Control Orifice (Passes < 1.41 cfs potential flow) =4" Perf. Underdrain (Passes < 0.31 cfs potential flow) =18' Emergency Spillway (Weir Controls 16.09 cfs @ 1.87 fps) Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92rr Prepared by {enter your company name here} Printed 2/13/2023 W Pond 3P: DETENTION POND Hydrograph I :fs -L--L-J--J--L--L--I--J--1--L--I--J--1--L--L--I-- I I I I I I I I I I I I I I I I r ,--,--, l' f lowlAceia 246(Y"- I I I I I I I I I I I I I I I I I --J--L--I--J--J--L--L--I--J--1--L--I---I- ____J--L--L--I-- S#oragq=;2y77S'}cf- I I I I__ II I I I III --T---- ,--T--I --I --I-- T --I---------I --I --I-- --J--I ---------------------------------- I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I -r -I -1 -, -r -r l I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I _ I I I I I I I I I I I I I I I I I 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (cfs) ■ Inflow ■ Pdmary ❑ Primary Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92rr Prepared by {enter your company name here} Printed 2/13/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Page 34 Pond 3P: DETENTION POND Stage -Area -Storage Surface/Horizontal/wetted Area (sq-ft) 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 ■ Surface ■ Storage I I I I I I I I I I I I I I 518 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 517 I I I I I I I I I I I I _1_1 _1_J _I I I I I I I I I I I I I I I I I I I I I I I I I I I I I T 516 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I C I I I I I I I I I I I I I I W I I I I I I I I I I I I I I I I I I I I I I I I I I I I W 515 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I _____�_�_ _r___r_�______r_____r__I r_r______I______r_r____I I I I I I I I I I I I I I 514 I I I I I I I I I I I I I I I I I I I I I I I I I Custom Stage Data 513 0 5,000 10,000 15,000 20,000 25,000 30,000 35,Ooo Storage (cubic %M) Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92- Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 35 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 3.68 cfs @ 11.96 hrs, Volume= 0.184 af, Depth= 7.35" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description 0.120 98 Unconnected pavement, HSG D 0.180 80 >75% Grass cover, Good, HSG D 0.300 87 Weighted Average 0.180 60.00% Pervious Area 0.120 40.00% Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: DA 1 - Offsite Managed Hydrograph _____-__y__y__ 4 ■ Runoff 3.68 cis Yy;pe 11', 24-Mr 100-yr Rainfa11:*8.92 3 RUnbff Areg=0.300 at, �4n4ff1 VP1tjmle=0.184 elf.� A;tuneff7bepO47:35R'- 2 E Tc=5.0 tinih N=8 J All i� 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 36 Summary for Subcatchment 4S: DA 1 - Orl Un-Managed Runoff = 5.04 cfs @ 11.96 hrs, Volume= 0.243 af, Depth= 6.61" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description 0.050 98 Unconnected pavement, HSG D 0.390 80 >75% Grass cover, Good, HSG D 0.440 82 Weighted Average, UI Adjusted CN = 81 0.390 88.64% Pervious Area 0.050 11.36% Impervious Area 0.050 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 4S: DA 1 - Onsite Un-Managed Hydrograph i 5.04 Cfs ■ ixunmr ' Type II' 24-hr 100-y,r Rainfall=8.92" 4 Runoff Area=0.440 ac Runoff Volume=0.243 of 3 Runoff Depth=6.61P' Tc=5.0 milk 2 UI Adjusted CN=81 1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 2/13/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 37 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 4.30 cfs @ 11.96 hrs, Volume= 0.206 af, Depth= 6.49" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=8.92" Area (ac) CN Description * 0.010 98 Unconnected pavement, HSG D 0.370 80 >75% Grass cover, Good, HSG D 0.380 80 Weighted Average 0.370 97.37% Pervious Area 0.010 2.63% Impervious Area 0.010 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, Subcatchment 5S: DA 1 - Offsite Un-Managed Hydrograph I I I I I I I I I I I I I I I I I I ■Runoff I I I 4.30 cfs --- - - --Type-1124-tir 'I OO-ylr I_ I_ j_ L I_ I a I I I I I I I I I I I I I RlainfallT8.92"r I I I I I I I I I I I I I I I I I RUnbff Area=0.380 alp 3 rkOnpfflll Vgkpm;e=0.�00 elf kunoff IIIDep'hT6.49, I I I I I I I I I I I I I I I LL I I I I I I I I I I I I N=Ig I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hours) Channel Protection: Energy Balance Equation with Run-on for POA 1 Forest Lakes Self Storage 1 Yr, 24 Hr Storm Comparison Q 1post < Q t Pre, site ((RV t Pre, site)/(RV 1 Post, soc))(I.F.) + Q 1 Pre, oosrte ((RV 1 Pre, offsrte)/(RV 1 Post oosite)) I.F. = 0.8 when LOD > 1 ac, I.F.=0.9 when LOD < 1 ac, I.F. = 1.0 when predev site is fully forested PreDev Site Fully Forested? = no I.F. = 0.8 Limits of Disturbance = 3.14ac Onsite Offsite Pre Dev Area Offite = 2.86 ac Pre Dev DA Offsite = 0.42 ac Post Dev Area Onite = 3.10 ac Post Dev DA OflSite = 0.68 ac Q t Pre, Sac = 3.80 efs Q t Pre, otrt, = 0.76 efs RV t Pre, site = 0.294 of RV t Pre, otnte = 0.058 of RV t Post, site = 0.503 of RV t Post, onite = 0.082 of Regulatory Maximum Postdev 1-yr Flow Rate Max Qtpost < 2.31 c[s Achieved Design Postdev 1-yr Flow Rate Design Qtpost = 2.11 cts Energy Balance Equation Compliance Check: Achieved Notes: 1. The assumption in the calculation above is that the site equals the land -disturbing activity (LDA). The definition for "site" is not clearly defined in the regulations, but LDAs are defined as regulated. The water quantity criteria are applied to the site as per the regulations. 2. This site discharges to an outfall at an existing drainage structure. Since postdevelopment runoff to this outfall meets the energy balance equation, Channel Protection Requirements per 9VAC25-870-66-B.3.a are met, and channel protection requirements are satisfied. Flood Protection: Peak Flow Rate to Existing Drainage Structure for POA 1 Forest Lakes Self Storage 10 Yr, 24 Hr Storm Comparison Regulatory Maximum 10-yr Flow Rate Qropm = Max Qlopost = 12.02 cfs Achieved Design Postdev 10-yr Flow Rate Design Qtopost = 11.28 cfs Flood Protection Compliance Check: Achieved Notes: 1. It is assumed that the existing drainage structure is inadequate prior to reaching 1 % of the watershed. Forest Lakes Self Storage LD-204 Stormwater Inlet Computations Inlets on Grade Only sag Inlets Only ` u `w o V E > Z n n n w a `v n r O E C m Z w i s ... - c Eig w w m u t c o f a o m t`n z' 0 0< of 6 o 0 0 3 � a (� rh � � o o E� 0 3 E� 1 2 3 4 5 6 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 (ft) (s0 (ac) 0FV ) (ch) (cfs) (cfs) ('r) ('/) ('f) (ft) IT (cfs) (of$) (ft) (ft) (ft) A5 DI-3B 8 13,501 0.31 0.80 0.25 5.2 1.28 1.28 0.015 0.02 0.03 0.01 0.132 0.5 0.264 5.281 6.2 1.53 1.53 0.015 0.149 0.5 0.298 5.948 A4 DI-313 8 7,832 0.18 0.80 0.14 5.2 0.74 0.74 0.015 0.02 0.03 0.01 4.80 0.12 98.9% 0.73 0.01 #DN/01 6.2 0.89 0.89 0.015 5.14 0.13 96.1% 0.86 0.03 #DIV/01 A3 DI-313 8 15,303 0.35 0.85 0.30 5.2 1.54 1.54 0.015 0.02 0.06 0.01 0.149 0.5 0.298 2.489 6.2 1.85 1.85 0.015 0.169 0.5 0.338 2.813 B4 DI-313 8 8,671 0.20 0.90 0.18 5.2 0.93 0.93 0.015 0.02 0.02 0.01 0.107 0.5 0.214 1.778 6.2 1.11 1.11 0.015 0.12 0.5 0.24 2.001 B3 DI-3B 8 7,455 0.17 0.90 0.15 5.2 0.80 0.80 0.015 0.02 0.02 0.01 0.097 0.5 0.194 1.609 6.2 0.95 0.95 0.015 0.108 0.5 0.216 1.804 LD-229 Storm Drain Design Computations From Smutuie To Structure Catch. Area ac Runoff Coef Increment AC Arm.. AC Total TOC min 10-yr Intensity in/hrOctal 10-yr Flow Up Invert Elev. Down Invert Elev. pipe Length 9 Invert Slope % Pipe Diameter in pipe Capacity cla Velocity Ns Flow fime Increment min 1 Br 2 B3 3 0.17 4 0.90 5 0.15 6 0.15 T 5.00 8 681 9 1.04 10 518.56 11 517.11 12 116.00 13 1.25% 14 15 15 1.4 16 3.8 17 0.51 B3 B2 620 0.85 0.17 0.32 5.00 681 2.20 516.91 516.12 63.50 1.25% 15 2.9 4.7 623 B2 Bl 0.00 0.80 0.00 0.32 5.00 681 2.20 515.92 513.86 164.50 1.25% 15 2.9 4.7 0.59 B1 SO 0.15 0.75 0.11 0.44 5.00 681 2.97 513.66 51300 5300 1.25% 18 4.0 4.7 0.19 AS A4 0.31 0.80 0.25 0.25 5.00 681 1.69 518.23 516.36 125.00 1.50% 15 2.4 4.6 0.45 A4 A3 OAS 0.80 0.14 0.39 5.00 681 2.67 516.16 51424 128.00 1.50% 18 4.0 5.2 641 A3 A2 0.80 0.90 0.72 1.11 5.00 681 7.57 514.04 513.00 69.00 1.50% 18 9.5 5.6 0.20 Outlet Protection Calculations - Reference Nomograph 3.18-3 Pi a Outfall # La ft W ft Do in Do ft Mo ft d50 ft d50 in Depth in A2 9 1 10.5 18 1.5 1 4.5 0.5 1 6 9 BO 9 1 10.5 1 18 1 1.5 1 4.5 1 0.5 1 6 1 9 BO 6 1 6.67 1 8 1 0.67 1 2 1 0.5 1 6 1 9 Stormwater Quality Calculations: VRRM Pre -Development Land Use Map VRRM Post -Development Land Use Map VRRM Re -Development Spreadsheet FOREST LAKES SELF STORAGE PREDEV VRRM MAP r-IFFEWN \ \ OB C. -� ' SEMEN aT \ III110 6 PG I491 T] I I/ II \ ` \ I \ 10' ACCESS PG EAS19] flA�11T n DB 1 DD w Pc ne 1F' N„T s OR 1169 PG ND 6 N] 4I91t'23W ID.on DO 40B Pc ]]g§a1 p P \ DB I6TZ Pc 153 (PLAT) \ �..; •��;. •.� •. •.• •''`'\�.•.'.;' t, •.Y ':I-j,E- ' nBa PL ASS+ \' 1.•' �( \ FWD LION 52994'VS'W , VARIABIE MDIN STORM SEWER EASEMENT DR 1281 PG Jaz r :r::::::. a:: N2912.59'E 158.50'••- • ••-•••••-•••-•••-•••`.•••- '••-••••••' -•�•- • /••�• ••'•'•••'•••••••••••••'�••••••••••••'••••• • ••••• • ••• 444444 ♦ 1 WS'Jz.iA01 LY11ED vJTgCRA71C t �. • - fill &QO Al 3 \' •a' x' 1'•'I• ' ADVANCE .m PARTS TAP 32-37CI N/ GEORGE R. @ MART R. MERCER DO JSRz PG 181 D8 W22 PG 194 (PLAT) NRGINIA TELEPHONE & TELEGRAPH EASEMENT DO 271 PG 495 ^J DR no PG 102 V ,I ACCESS EASEMENT R 32 PG 404 3 EASEMENT P. 16' C00 lRSD fi GN IV • •b. ••••••••••••••••••••••••• ••••••••••••• \ ••�•;{;'• /••• i NEE JA-2AN LIMITED PARTNERSHIP y L • 1 ff `r/ JT I ZGN1 PD-SC ••\.• '•'•'•'•'•'•'•'•'•'•'•'•'•'C •'•. .t. •.• .TJ •. jil DO TIN PC]B2 �::::::::::::................. ............................. • '•'•'•' ' ' ' ' ' ' ' .:.:.:.•:•:•:•:•: I: ' �... i �r 1:....:;� ;. .•.•.•1 : 1 • :• •'•'• /• •J ••'•'•'•'•'•'•'••b •'� / VA41E'MOTH STCIiM SERER ✓• EASEMENT . •�• . • DO 1181 PG 142 9105I'CB:•N• SE23'' - 1 TH cRosslNc l \ o ii R \ D 1ae Pc IOJ tz90 PG J96 •OT-•�I.. �ry� •I •9 ONSITE LAND COVER: DISTURBED AREA = 3.29 AC IMPERVIOUS = 0.00 AC TURF = 3.29 AC WOODS = 0.00 AC 60 120 N 180 0 FOREST LAKES SELF STORAGE POSTDEV VRRM MAP rAUTO , D. IN' ....., �� . ...` r......YiirY kSYY aY�ty ........c.0 ♦.iU r`?#ar#I.�t' ♦flat♦ at♦ !Y ♦•`tal. . .t/„I.4 _'a.Na.ati ati♦ tt .� , ...... 1 iYi t3Y.................. rr#r #Y ♦..a♦ ..a..a..t..a..a..a..a.♦ ♦s♦'♦.t..rca tl ♦..r1 ♦r..........a..a..a..a..a.s a as .. t♦ tra ��, ..tat.artartartar..#### . tr:�IIII ttttt attttta .. ttttf4tfttfttfttf4l 1 at.attart Vtattattattatta.tattatt♦ ♦ti.11tat�r 999t,Zii r.artar.rr�r-rtatratratratr,aratratratt.r.r ♦1 r.a �� \ !; a.ai.a».aar•atattattattatt.ttattattatt»tta4w'�(�e,q(ii .[ z.;riiaiiev.i.ir..♦♦.......o...........a..r��i"�i r:r. �, �tsrasaas.atattattattattattatta:3t attattaarr ♦n ♦aaa♦♦..1a♦♦.♦♦.♦♦..a..a..a..a..at.rt.♦}J�r.a. 'Yr r.rrr'lir#rtattattattartavtaatattattar Yrr##. rJ _ .##arr v.erratraaraarar.#rraa♦a)�trattarrllr#i#.) . i.ti'.ta#.ttattatt♦�•Y *�.tis a[Y t�♦tt aitttt.t'a.ti�f..�'. Sri#Y'YLY �......♦ Y 4 ..�SYYV <i......rii�#Ilrr �#+• r ata.taa.ar.at.:t:♦ xr}v;�.'♦ :::. �. ♦.:.Ya.t.♦ .i..: ) (. ♦.ar.al.a.a.t..t..♦ :t�♦t..t:�. ♦..�n.a....s'a. nl 1.tt.a rl tttttPttttttttttttttt a�tta tit ttf rt.tir ,l�'il 1:tia♦♦.♦�a.♦♦t♦♦♦♦at.at.at.at.at.Pt.a.t�aa.a..1 a.♦ta..a...t..t.at..t..t..t..t..cy ♦..n ♦..a..d ,, �:3![ :>s..t. •................. :jai :)�:jy�:)�:j�i..t. at.Y..r ail q'F � �r1♦tattattattattatt♦�t�a����t�a����i�a ♦ta r�taY.a 4�(I ........♦.at.at.at.tt.at.at.a.aa.taas.a l:` t �.t: a♦�t.♦tt.tt.tt.tt.tt.tt.tt.tt.tt.. Y�t♦ � Itt^. rrtttttttttttttttttt tttttttttta�altt♦ a(I .�j�iiu��j�fa�% r t. a t t a t t a t a a t t a t t a t t a t i� ♦ t t a t a♦ t[ a f a a a s .( wp UOU P .r. v. a.at.at.at.at.at.at.al.at.at.a1 �'1Y Y..�� ♦ill ♦ ............................'.. ♦i # ' tr . ♦..at..t..t..t..t..t..t.3. t..t..t....aa.� f1'p t rttattattattattattat♦♦�ta♦♦.a ♦t.�tr. i. vT ���!, / ��' ..ttatt�♦ttattattatta4t ♦�tt♦tit ♦tt�. t4 tt Y�( r.�♦.t.tt.tt.tt.tt.tt.tt.�tt♦t�7t.Yt rt.N 4t-i .� � '—'— ---=....r.♦-,. .,arr iriif .i r# x4t z r a i a-r�<_.. r+.�.+' .".••!Y � asE ..... z, (s Y . 3j2 �—� ter`• i 1 _i� ��--_,n:.esa,... �'Y.Yy'NS (Yi i r ##r •� ONSITE LAND COVER: DISTURBED AREA = 3.14 AC IMPERVIOUS = 1.78 AC MANAGED TURF = 1.36 AC WOODS = 0.00 AC 60 120 N 180 OEG WMinia Runoff R U&on MCMOE New mveiapm E WftnreSgeaEiM1eel- c2p11kks5brmtlsaMSp� 02023 ora aMeSU darft aM S peM=Ims proles Nana: 1 Form lakes Self Romp Oab: 2/13/2M BMYOesign Specifirmiam tisf. nnsGMs x.mrmiprcne:l 43 .w,n E.msnnC 1.m TM I m. RVIFMCM nxE �m m+IEmcImW 1.M is rgetm Wea 114/eve/yrl OA] vl lvrms�m�m.eavrl o.m 3.0 0. Site Results (Water Quality Compliance) Area Checks FOREST/OPEN SPACE (a[) D.A.A am D.A.B 0.00 D.A.0 0.00 DA.D 0.DO O.F.E O.W A.-CHEM OK. IMPERVIOUS COVER(a[) am 0.00 0.00 0.00 0.00 OK. IMPERV��GED TUEAAREA Ia[) 0.00 0.00 DOD 0.00 0.00 OK. MANAGED TURF AREA TREATED Ia[) 0.00 0.00 DOD 0.00 O.00 OK. AREA CHECK OK OK. OK. OK OK. Site Treatment Volume (ks) 7.373 Runoff Reduction Volume and TP By Drainage Area D.A. A D.A. B___j D.A. C D.A. D O.A. E TOTAL RUNOFF VOLUME ACHIEVED 0 0 0 0 0 LOADAUOION (lb/ TP LOADAVAINBLE FOR REMOVAL Qb/yrl 0.00 O.W 0.00 � 0.00 O.M 0.00 TPIDADREDUCnONACHIEVED)Ib/yrl 0.00 O.00 DOD 0.00 O.W 0.00 TP LOAD REMAINING IIb/yr) 0.00 O.W 0.00 0.00 O.W am MMOGEN LOAD REDUCTION ACHIEVED pb/yrl am 0.00 0.00 0.00 O.W 0.00 Total Phosphorus FINAL POST -DEVELOPMENT TP LOAD (lb/yr)) 4.63 TP LOAD REDUCTION REQUIRED pb/yrl 3.34 TP WAD REDUCTION AOIIFVED lb/yr) 0.00 W WAD REMMNING Qb/N): 4.63 REMAINING TP LOAD REDUCTION REQUIRED (Ib/yr): 3.34 Total Nitrogen (For Information Purposes) POST -DEVELOPMENT LOAD IIb/yr) 1 33.14 NITROGEN LOAD REDUCTION ACHIEVED Pb/yrl am REMAINING POST -DEVELOPMENT NITRWEN LOAD Pb/yrl 33.30 WgMa Runde RMumon Wed] wonelmet DED Virginia Ruroff xedualon Medm d New Developmem CompllaMeSpreadsbeet - Ver lon 3.0 RMP Oeiyn Spe[ifrcodons list: . Site Summary Pmlert isle: Forest lakes Sel6mre, Date: usTo Total Rainfall= 63 inches Site land Cover Summary R mils BSons CStlls BSons Totals MofTotal Farem/Open(acres) 0.00 0.00 0.M 0.00 7M 0 Managed Tud(acres) 0.00 0.00 0.N 1.3fi 1 L.m 03 mpeMous Caver(acrtx) oao oao 0.N 1.]9 1.78 n 3.14 ao Site Tv and land Cover Nulrienb lade e, R 0.. TrealmeM Volume 7,373 Tl Wad(Ib/yr) Ob3 Tel load pb/nl 33.10 1-1 Redunion ReRumed(Ib/yrl 3.30 Site Compliance Summary Total Runoff Volume Reduodon(W) 0 Total TP Wad ReduNon oxhleved (lb/y') n00 Total TR Wad Reduction F Ieved(lb/,) 0.00 Remaining Pml Development TP Wad pb/yrl Obi Remaining TP Wad Reduction (Ib/yrI a..Requlme OAR 1 OAB OA.0 OAO OA.E Toral Fore4/Open(acres) O.W O.N 0.00 0.00 0.00 0.00 Managed Tud(loom) O.W 11 0.N 10.00 0.00 0.00 0.00 Impervious urer(mrmd 0.m 1 0.m 1 Von oao Of. oao TWI Arm(aves) I 0.. I ..an I0.00I n00 I Win Drainage Area Compliance Summary OA.A DAB OA.0 DA.O DAE Total TP Load Reduced! Ib/ r O.N O.N 0.00 0.00 0.00 O.N TR Mad Reduced(Ib/yr) om OM 0.00 I o.Co lrynrnmum I Synrnmm I �wmnmm Target Rainfall Event (in) 1 3.00 1 3.fi0 1 S.. Drainage Fnvs RVBCol Den ye MeaA Ominage AMME palm,¢ArmC manage Area Drainage Ares x o 0 o a o RR Ilr o 0 0 0 0 1-year Mum perlod na (min) nC0 000 0.0] oM nC0 Rue Mr -I.) nC0 000 0.00 oao nC0 Co.,... o 0 0 0 0 ]-year Mum omal EM lm+nl nm om o.00 om nm RR la+lnl nC0 off O.W off 6C0 Heented o 0 0 0 0 10-year mourn period Imo NeA.) nC0 off O.W off nC0 weM la+lnl den off O.W off nC0 Haalvuea o 0 0 0 0 morm, Port Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report �°7'%N 3P ]'43-N 3 Hydrologic Soil Group —Albemarle County, Virginia 3 o (Forest Lakes Self Storage) I v 3 743'N R4E0D n4 724510 T1A610 iMTil T M n2 Tt 10 TN0I0 72%130 72C0D 3 3 Map Smle: 1:2,93D if prnrted on A lardsape (11" x 8.57) 4mt. N Me ers 0 40 a1 its 240 Aa ,m � 4m 600 Map pmjemon: Web Me bob Carer mordinata: WG584 Edge ti¢: UR47rxie 17N WG584 USDA Natural Resources Web Soil Survey 6/30/2022 4101111 Conservation Service National Cooperative Soil Survey Page 1 of 4 MAPLEGEND Area of Interest (A01) 0 Area of Interest A01) Solis Soil Rating Polygons 0 A Q AID o B Q BID o C 0 CID 0 D 0 Not rated or not available Soil Rating Lines . r A ,y AID rV B ram/ B/D N C N CID i D . . Not rated or not available Soil Rating Points A Q AID O B 0 BID Hydrologic Soil Group —Albemarle County, Virginia (Forest Lakes Self Storage) 0 C CID D 13 Not rated or not available Water Features Streams and Canals Transportation µ� Rails N Interstate Highways �y US Routes Major Roads Local Roads Background . Aerial Photography MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:15,800. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey LIRL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Albemarle County, Virginia Survey Area Data: Version 15, Sep 13, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jun 8, 2020---Sep 23, 2020 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USDA Natural Resources Web Soil Survey 6/302022 Conservation Service National Cooperative Soil Survey Page 2 of Hydrologic Soil Group —Albemarle County, Virginia Forest Lakes Self Storage Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI 27B Elioak loam, 2 to 7 percent slopes B 0.2 1.4% 28C3 Elioak clay loam, 7 to 15 percent slopes, severely eroded B 1.1 6.5% 34D Glenelg loam, 15 to 25 percent slopes B 2.2 132% 88 Udorthents, loamy, 2 to 25 percent slopes 13.1 78.9% Totals for Area of Interest 16.6 100.0% Natural Resources Web Soil Survey 613WO22 Conservation Service National Cooperative Soil Survey Page 3 of 4 Hydrologic Soil Group —Albemarle County, Virginia Forest Lakes Self Storage Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long -duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink -swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie -break Rule: Higher Natural Resources Web Soil Survey 6/30/2022 Conservation Service National Cooperative Soil Survey Page 4 of 4 NOAA Atlas 14, Volume 2, Version 3 Location name: Charlottesville, Virginia, USA's.,,,,, Latitude: 36.1299°, Longitude:-76.4353° Elevation: 521.79 ft" g a "source: ESRI Maps 1A "" source: USGS��"""" POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Average recurrence interval (years) Duretion 1 2 5 10 25 50 1 100 00 200 500 1000 5-min (0.3016-0387) (0.307A-0.462) (0.442-0.542) (0.496-0.609) (0.557-0 685) (0.603-0 78) (0.65-0.93) (0.684-0 858) (0.730-0 928) (0.765-0.985) 10-min (0.504-0618) (0.6 3-0739) 6 (0.707-0.8) (0.7930975) (0.8899109) (0.9601.19) (1.03i27) (1.09-21336) (1. 5-3147) (1.211.��55) 1.46 1. 1.7 15-min (0.60-0. 73) (0.758-0929) (0. 95-11.10) (1.0-?23) : (13-21639) (1.22-31750) (1.0-1..61) (1.37--1.72) (1. 5-01785) 1 (1.511695) 30-min (0864---1170) 1 (1.05-1..28) 1 (1.274.56) 1 (1.45- .79) 1 (1.67-2605) (1. 3-2..26) (1.992.47) (2.13-2?67) (2.31-22..94) (24 58315) 1.19 4.15 60-min (1.08-1..32) (1.3A561) (1.632.0) (1.892.33) (2.2�73) (2.8-3..07) (2.74-3940) (2.993075) (3.32-422) (3.58461) 2.18 4.36 5.52 2-hr �97) (1.274362) (1.54 (19 32.5) (2.27--�2.89) (2. 9-3.44) (3.043?91) (33 9-4.39) (3. 54.89) (42 4--5.61) (46 5-6.23) 2.79 4.27 3-hr (1.38-1.79) (1.67-2..17) (2.9-272) (2.45-3.18) (2.91�79) (3.9�31) (3.68-485) (4.0775.42) (4.618.22) (5.06-6.91) 6-hr (1.77 227) (2132.74) (2.643.40) (310 4.00) (3.704.80) (4.225?50) (4.746324) (5. 0-�06) (6.07 8 23) (6.749.27) 3.02 7.22 11.2 12-hr (2.21206) (2.67-3.45) (3.31�60) (3.91�08) (4.715z16) (5.41�13) (6148.19) (6.929535) (805-161.1) (9.04-2.7) 298 4-hr (2.68-3.36) 61 (32 4-4.0) (4. 25718) (4. 6-6.11) (5.92-67A9) (6.8285 66) (77 8-9.95) (8.82-111A) (10.3-13.5) (11.6-15.4) 2-0ey (316-3.93) (3. 3-4.76) (4. 68.04) (57 0-7..09) (6.88-8.60) (7.85 9987) (8.88- 1.3) (9.99-12.8) (11.6-15.0) (12.8-16.9) 3-day (33 94.15) (4.141503) (5.218.38) (6.111-748) (7. 89?08) (8. 2- 0.4) (9.53-161.9) (10.72- 3.5) (12.4-15.8) (13.8-107.8) 4-day (3.63-4.38) (4. 95.30) (5.568.72) (6.52-17..88) (7.889.57) (9. 0-11.0) (102- 2.5) (11414.2) (132-16.6) (476- 8.7) 7-day (4.225A6) (5. 9-6.09) (6.35--74.61) (7.37 8885) (8.8210.6) (10.00-12.1) 1 (11 2?13.7) 1 (125-15.4) 1 (14.3-18.0) 1 (15.8- 0.1) 10-dey (4.82- 69) (5. 8-6.82) (7138.42) (8.21 9571) (9.72-111.5) (10.9- 3.0) (122--14.6) (135--16.3) (15.3- 8.7) (1618- 0.7) 20 day (6.43- .39) (7.678 4.81) (9.2-110.6) (10.5 2.1) (121314.0) (13.4-15.5) (14.7-1 1) (16?0- 8.8) (17.7--21.0) (19.0. 2.8) 30 day (7.939.01) (94 0- 0.7) (11 1' 2.6) (12.414.1) (141--16.0) (15.317.5) (16.5 8.9) (17.7---20.4) (19?2-22.3) (20.323.7) 45-day (9.9411.2) 1 (11 7?13.2) 1 (13'7- 5.4) 1 (152-17.1) 1 (17.0-19.2) 1 (1849 0.8) 1 (197'22.3) (20?9- 3.8) (22?5-25.8) (23.6-27.3) 60-day 2.2 (117 3.1) (13.8-1-5.4) (15.9--8.7) (1748.5) (19.421.8) (209?23.4) (22225.0) (235-26.5) (2521628.5) 11 (262$ 9.9) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA AOas 14 document for more information. Back to Top PF graphical