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WPO202200050 Calculations 2023-01-11 (2)
SHIMP ENGINEERING, P.C. 1 Design Focused Engineering C o� Lr? January 10, 2023 Engineering Review O M. IMP y Albemarle County Li o. 45183 Departmen of Community Development 401 McIntire Road A�,o 11012� ww� Charlottesville, VA 22902 `� s, _ oc�G` 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 3.29 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 Run-on for POA 1 Forest Lakes Self Storage 1 Yr, 24 Eir Storm Comparison Q lee--QIft. ae((RV Iee•sm)'(RVt➢eu.sv.)xl.F.)+Q Iac,((RVIpmv Y(RV Ieogomie)) LE - 0 8 when LOD z: 1 ac. LF.-0.9 wdten LOD a 1 ac. IF. -10 when predev site a wily forested PreDev Site Fully Forested' - no LF - 08 Limits of Disturbance - 3.29 ac Ofsite Offsite Pre Dev Area Onsite - 286 ac Pre Dev DA OSssR - 0 42 ac Post Dev Area Onsste - 327 ac Post Dev DA Offide - 055 ac Qto'- 380 cfs Ql Py one. - 076 cfs RV I ft, - 0.294 of RV i t.ti ottm - 0 058 of RV I Pons, sae 0.512 of RV I Axa Daze 0 064 of Regulator}- 31asmum Postdev 1-yr Flow Rate 31ac Qi,,, <_ 2.43 cfs Achieved Design Postdev 1-yr Flow Rate Design Qie.n - 1.93 cfs Energy Balance Equation Compliance Check: lrhieied Notes 1 7be nsumpuon in the cilevlanoa abme u Wit the use equals The Lod-dismbo; achsvy (L.DA) The de5muon for 'vx' u mi cleady denned is the reguatio but LDAsam defined as regulated,Me water quaooy mama art apphed to dw ute a per the regulations ]ins sue dnebmges L eamufi0 at mf%10129 drmmge stMt Stme pa tdnelupmeal rmoff to din mr1Ln neat%the emgy balance CLamelPmt P,equvementsper9VACS97D4&B3aaremet,aideba Aproteetimrequirements Ksmu6ed 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. to Lakes Self Storage 24 Hr Storm Como tor} Dfarimum 10-yT Flow Rate Max Qtopn — 12.02 cis ced Design Postdev 10-NT Flow Rate Qnpn = 11.14 cfs Pt otection Compliance C.--heck: It. assumed that the esiving drainage str me uivadcgtutep.o to teaching I%ofdew leshed. Water Quality: According to the VRRM New Development Compliance Spreadsheet, a TP Load Reduction of 3.37 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 Drainage Area 1: Total Area = 3.28 ac OFFSITE DRAINAGE GR AREA TO POA 1 Onsite Area = 2.86 ac Managed Turf = 2.86 ac (HSG D) ACi171 oO 102 PG 11 \ \ 11 I/ / Impervious = 0.00 ac oe D69 P6 ai01s 34v \ l -�r �— \ rJ Offsite Area = 0.42 ac NNCINIA lE1EPManaged Turf = 0.29 ac (HSG D) HCNE & TE OGRAP PG SENT n \ \ \ \ I I Ga 280 PG 102 V Impervious = 0.13 ac (HSG D) v v v %'�� �� I �� Time of Concentration = 20.5 \ \\ I 1 \ OFFSITE DRAINAGE RIA01£MIOTIIAGA °'""EnE"""' 1 I �� \1 V VLAMIGRT EAMMENT \ DO 323 PO 44 AREA TO POA 1 \ OR ash PG �v$�� L IXOLIION E0.5ENENT 3526 / \ ONSITE DRAINAGE AV AREA TO POA 1 V"RI"0 EWOW A EMENTRM SENEA 06 101 PG 342 // / �- I ab VAM�ME EAYNEN` gMER RO/� 1 / / �^1 1281 PG 342 J / / .`1 6 �0 60 120 180 0e 104 PG 18 IS OBE1113`NPGRENT \ �/ \ z Scale: 1 `60' DA 1 - O 2L POA 1 Sub4 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 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 3 Summary for Subcatchment 1 S: 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) (ft/sec) (cfs) 20.5 Direct Entry, 3.80 cfs Subcatchment 1S: DA 1 - Onsite Hydrograph Time (hours) _____ �__ ❑Runoff ,Type II 24-hr 1-yr Rainfall=2.98E Runoff 'Area=2.860 ac Runoff Vplume=0.294 elf Runoff Depth=1.247 Tc=20.5 Min CN=80 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/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 5 Summary for Subcatchment 3S: DA 1 - Mite 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) (f /ft) (f /sec) (cfs) 20.5 Direct Entry, 1 1 0.8 07 0.75 1 07 0.65 0.8 0.55 0.542 0.45 3 0.4 c u. 0.35 0.3 0.25 0.2 --r-r--r--r--r 0.15 0.1 0 05 J Subcatchment 3S: DA 1 - Mite Hydrograph 1 1 1 1 1 1 --;---�--;--;--;--1rR�ii"1ff�fh2.9�� _I ------=--=--=--trnssff' �6=©_42aad- I I -----RI I I I I --- -- -- -- --;-- -- -- UnOff lQe th I -Oil,_ I 1 i i i I 1 i i i I IT 1 i I 1 ON40_ 1 1 i i i 1 1 i i i 1 1 1 i i 1 1 i i i 1 1 i i i 1 1 i i i 1 1 1 1 i i i i 1 i i i i 1 i i i 1 1 1 1 1 1 I 1 1 1 _1__J__J__y__L_--- __1__J__1__}__L1__y__L__I__ 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 Time (hove) ■ 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 I I I I I I I g I I I I 7 I I I I V 6 I I I I 3 ----,--,--� p C 5 I I I I 4 I I I I I I 3 I I I I I I I 2 1 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 kiT bff-Afe -1-»60 ae �f- L -- -- I�unoff6ep#h4l.' &- I I I I I I I I I I I I i I I I I I ,--r--I---I -, , , r , - -,---- IT&20 ;5-fnifi-- I I I I I I I I I I I I I I I I I N=-81 I I I I I I I I I I I -------------------------------------------------- I I I I I I I I I I I I I I I I I I I I I I I i I I I I -------------- I I I I I I I I I I I I I I I I I I I I I I I I i I I I I Time (hours) 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 8 Summary for Link 2L: POA 7 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 -1 _y _A _}__F__I _y _} _f _I _y _4 _f _F__I__ ■ Inflow 113 12 - 12.0c --+-anflawA' - 1;JIIIIIIIIIII ■Primary __�___JIIIIIIIIIIIIII 1oi ii 9 - -~ ~ -~ - 6, _ I-----------'--'M 7 I-- I1 p 6 _J__J__L__LJ__1__L__J__1__L__L_ LL3 6 _ y _f y _} q l__ _rr_rrr_r_1_r_r 1 1 2 _J__J__1_L_J__1__L_JJ__1__L__L_ I I I I I I I I I I 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 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- ,---- ;- ;- -- 19.9-6 _I___I__J__1__1__1__L__L__I___I__J__�__y__y__L__ ■RunO,F 1 _ ;--Y--Y--r--r--'r--I ;---I- r 'r 20 19 18 1 17 16 1 15 14 13 b 12 I 0 10 1 9 1 7 6 , 1 5 2 -- - -- - - -- ; glf''124=1 10_04jr- 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 €'tttto#'1Depttt�G 49F' 1 I I I I I I T_J I 1 -L--I I 1 --1-- ,--; W I I 1 1 1 I I I I 1 1 1 I I I 1 1 1 1 I I I 1 1 1 I I I 1 1 1 1 1 I 1 1 1 _r__r__r__1__,__r__r__r__r__r__r__1__r__4__r__r__r__ _L__I___1__ I I I I I I I 1 1 1 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 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--rt4n�)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 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 POSTD EV DRAINAGE AREA MAP OFFSITE DRAINAGE AREA Drainage Area 1: 1 TO POA 1 (TREATED) Total Area = 3.82 ac Onsite Area = 3.27 ac \ ) Managed Turf = 1.57 ac (HSG D) f \ OFFSITE DRAINAGE AREA ,�_ I r' Impervious = 1.70 ac (HSG D) � \ �_ TO POA 1 (TREATED) \\ j �� \ I i Offsite Area = 0.55 ac Managed Turf = 0.42 ac (HSG D) Impervious = 0.13 ac (HSG D) \ \ \ \ Time of Concentration = 5.0 � \ � V � �" zz OFFSITE DRAINAGE AREA x22 TO POA 1 (UNTREATED) \ \ I ONSITE DRAINAGE AREA \ I I OFFSITE DRAINAGE AREA / \ TO POA 1 (TREATED) I I / TO POA 1 (TREATED) y \ I I RD 15 I I e % v � ROA % \ ONSITE DRAINAGE AREA q \ ` \ TO POA 1 (UNTREATED) L 60 0 1 60 120 180 Scale: 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 1/10/2023 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=2.830 ac 58.30% Impervious Runoff Depth=1.97" Tc=5.0 min CN=90 Runoff=9.91 cfs 0.464 of Link 2L: PDA 1 Inflow=1.53 cfs 0.575 of Primary=1.53 cfs 0.575 of Pond 3P: DETENTION POND Peak Elev=515.19' Storage=13,556 cf Inflow=11.04 cfs 0.515 of Outflow=0.33 cfs 0.515 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.430 ac 27.91% Impervious Runoff Depth=1.43" Tc=5.0 min UI Adjusted CN=83 Runoff=1.13 cfs 0.051 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=0.120 ac 8.33% Impervious Runoff Depth=1.30" Tc=5.0 min UI Adjusted CN=81 Runoff=0.29 cfs 0.013 of Total Runoff Area = 3.820 ac Runoff Volume = 0.575 of Average Runoff Depth = 1.81" 52.09% Pervious = 1.990 ac 47.91% Impervious = 1.830 ac Postdev POSTDEV Type/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 3 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 9.91 cfs @ 11.96 hrs, Volume= 0.464 af, Depth= 1.97" 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 1.180 80 >75% Grass cover, Good, HSG D 2.830 90 Weighted Average 1.180 41.70% Pervious Area 1.650 58.30% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, I ^ ^ 10 I I I I I I I - I---I--L--J--� 9 I I I I I I I I I 6 I I I I I - I---I--L--J--; 7 I I I I I I I I I I ,--,--7 2 u 6 I I I I 3 --I---I--J--J--I 0 5 I I I I LL I I I I 4 I I I I 3 I I I I I I I I 2 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 S I1,,' 24-hr J-y�r I I I I I I I I I I I I I I I Rainfall:;2.98 I Rwnbff Areii=2.830 alp --L--L-------J--;--;- 1--4--L-----I--J--J--1--L--J-- ROnpffl, Vgkpm;e=;0.464 elf --r--r I r__T__T__T__ __r ,__1__T__r__ _ I _ _Un_-, 'I_De_pth_ �_1.19.71'__ _i _i _1 _I _I _J _J Tc=5.0 tinih I I I I I I I I I I I I I I I I I I I I 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=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 I I I I I I I I I I I I I I I T__T__T__r__r I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I i I I I I I i I I I I I I 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 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 4 Summary for Link 2L: POA 1 Inflow Area = 3.820 ac, 47.91 % Impervious, Inflow Depth > 1.81" for 1-yr event Inflow = 1.53 cfs @ 11.97 hrs, Volume= 0.575 of Primary = 1.53 cfs @ 11.97 hrs, Volume= 0.575 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) Postdev POSTDEV Type 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here) Printed 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 5 Summary for Pond 313: DETENTION POND Inflow Area = 3.260 ac, 54.29% Impervious, Inflow Depth = 1.90" for 1-yr event Inflow = 11.04 cfs @ 11.96 hrs, Volume= 0.515 of Outflow = 0.33 cfs @ 14.01 hrs, Volume= 0.515 af, Atten= 97%, Lag= 122.8 min Primary = 0.33 cfs @ 14.01 hrs, Volume= 0.515 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 515.19' @ 14.01 hrs Surf.Area= 7,213 sf Storage= 13,556 cf Plug -Flow detention time= 645.2 min calculated for 0.515 of (100% of inflow) Center -of -Mass det. time= 645.6 min ( 1,453.9 - 808.3 ) 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=0.33 cfs @ 14.01 hrs HW=515.19' (Free Discharge) 1=15" HDPE Out (Passes 0.33 cfs of 7.47 cfs potential flow) 2=48' Standpipe ( Controls 0.00 cfs) 3=6" Control Orifice (Orifice Controls 0.10 cfs @ 1.48 fps) =4" Perf. Underdrain (Barrel Controls 0.23 cfs @ 2.60 fps) =18' Emergency Spillway ( Controls 0.00 cfs) POSTDEV Prepared by {enter your company name here} W 11 04 12 I I I I I 9 I I I I I I I I I I 8. I I I I I 7 I I I I I ------'--r--I I I I I I 6 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 3 I I I I I I I I I I 7 Postdev Type/1 24-hr 1-yr Rainfall=2.98" Printed 1/10/2023 Pond 3P: DETENTION POND I I I I I I I I I I I I I I I I :fs--T--'r-�--7--}--r--I--7--}'//-��-r--I--Y 7--r/-�-r--I-- -Infldw r-------}--r--I rQgG—'f3'y rJav��il1 I I I I I I I I ------------ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0.33 cfs 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) Pond 3P: DETENTION POND Stage -Discharge Discharge (cfe) ■ Inflow ■ Primary ❑ Primary POSTDEV Prepared by {enter your company name here} Postdev Type/1 24-hr 1-yr Rainfall=2.98" Printed 1/10/2023 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 11 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 8 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 1.13 cfs @ 11.96 hrs, Volume= 0.051 af, Depth= 1.43" 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 0.310 80 >75% Grass cover, Good, HSG D 0.430 85 Weighted Average, UI Adjusted CN = 83 0.310 72.09% Pervious Area 0.120 27.91 % 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 1.13 cfs Type II 24-hr 1-yr 1 Rainfall=2.98" Runoff Area=0.430 ac Runoff Volume=0.051 of Runoff Depth=1.43 LL Tc=5.0 milli UI Adjusted CN=83 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 1/10/2023 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/1 24-hr 1-yr Rainfall=2.98" Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 10 Summary for Subcatchment 5S: DA 7 - Offsite Un-Managed Runoff = 0.29 cfs @ 11.96 hrs, Volume= 0.013 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 * 0.010 98 Unconnected pavement, HSG D 0.110 80 >75% Grass cover, Good, HSG D 0.120 82 Weighted Average, UI Adjusted CN = 81 0.110 91.67% Pervious Area 0.010 8.33% 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 7 - Mite Un-Managed Hydrograph 0.32 -- - -- -- -- -- ---- -- -- --------- -- -- -- - - ---- I I I I I I-- I-- I I--II-- I I--I---I---I-- I -- --I---I-- -- -- -- --I-- - 0.29 0.3 I I I CfS �- r 0.28 -yr 0.26 ��� , I I I Qrr�F i •\�iI.Ti. 024 - -J-- - -;---------;-- --- ft�iirOff`Atts=�'r20��IC- 0.22 I I I I I I I I I I I I I I I I I I I I I I 0.2 -------------- ------------------------------------------------- _ _ jagff;VQl01w:IO.Ot3_ f 0.16 -- --I -� -� -� -I - '- - - - '-- - -=-----'- I�unoff-'I©ep�Fi�4:3fl�'- 3 0.16 0.12 0.1 0.08 I I ____________------- __________________________________________ 0.08 / __r_y__y__}____r_ 004 , --L-J--,--1---�--L--�--L--L--�---�--L--1--L--�---�-- �--1--L--L--�-- 0.02 1 1 I I I I I I � I � � I 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 Time (hove) ■ Runoff Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 1/10/2023 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=2.830 ac 58.30% Impervious Runoff Depth=4.30" Tc=5.0 min CN=90 Runoff=20.65 cfs 1.014 of Link 2L: PDA 1 Inflow=11.14 cfs 1.300 of Primary=11.14 cfs 1.300 of Pond 3P: DETENTION POND Peak Elev=516.42' Storage=23,182 cf Inflow=23.38 cfs 1.143 of Outflow=9.09 cfs 1.142 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.430 ac 27.91% Impervious Runoff Depth=3.57" Tc=5.0 min UI Adjusted CN=83 Runoff=2.74 cfs 0.128 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=0.120 ac 8.33% Impervious Runoff Depth=3.38" Tc=5.0 min UI Adjusted CN=81 Runoff=0.73 cfs 0.034 of Total Runoff Area = 3.820 ac Runoff Volume = 1.300 of Average Runoff Depth = 4.08" 52.09% Pervious = 1.990 ac 47.91% Impervious = 1.830 ac Postdev POSTDEV Type // 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 1/10/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 12 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 20.65 cfs @ 11.96 hrs, Volume= 1.014 af, Depth= 4.30" 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 1.180 80 >75% Grass cover, Good, HSG D 2.830 90 Weighted Average 1.180 41.70% Pervious Area 1.650 58.30% 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 23 zz 20.65 21 20 18 ,% 16 15 14 --r--r-,--,--T 13 __L_!__J__J__.I 'S,2 LL 10 I I I I I 6 i I 4 --r--r--I--r--i � 3 2 0 2 4 6 8 10 12 Hydrograph T--T--r--r--r--r--r-,--�--r--r--r-- ■Runoff J__1__ 1__ L__ L__I__I__ J__ J__ 1__ L__ L__ - r----*Ype-'Iq- 4i[u;'� IT I I I I 1 I I I I I I •1'I��FY'[s���r- I I I I I I I I I I I I I I I I I .--.=_I -rnbffAEee=Z830ad- I I I I 1 I I I I I I I I I I I I - - [1Qll_IJlLIIT�l.3o�r - _ __ I I I I I I I I I I 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 N=-9 -_r__r_______y__y__y__r__r__r__I___I__y__y__ r_ __ 1 I I I I 1 I I I I I I I I I I I I 1__L__L__I__J__J__J__1__L__I 1 1 1 __y__T__T_____r__r__I___I__y_____t__t__r__ 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 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 13 Summary for Link 2L: POA 1 Inflow Area = 3.820 ac, 47.91 % Impervious, Inflow Depth > 4.08" for 10-yr event Inflow = 11.14 cfs @ 12.03 hrs, Volume= 1.300 of Primary = 11.14 cfs @ 12.03 hrs, Volume= 1.300 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs 12 I I 11.14 cfs I I I I .10 I I I I I I I I 0 I I I I 8 I I I I Vp- I I I I 3: 3 6 __1__J__{__L- 0 I I I I LL 1 5 -_'_-J--,--L- 1 1 I I 1 1 I I 1 1 I I 3 1 1 I I __1__J__y__L. 2 j 1 1 I I ----J--,--L- 1 1 I I i Link 2L: POA 1 Hydrograph _I__ J__1__ L__L__I__- ❑ Inflow ❑Primary -,--�- �- �- �--�-I'ILin�low!A�e�a=38�O11La�-- I I I I I I I I I I I I I I I I _J _L _I _J _J _A _L _I _J _1 _L _I _J _i _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 I I I I I I I I I I I I I I I I J__+__L__I__J__+__L__L__I__ 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__y__L__I__J__;__L__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 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I JJ__+__L__I__J__+__L__I__J__+__L__L__I__ Time (hours) Postdev POSTDEV Type/1 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here) Printed 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 14 Summary for Pond 313: DETENTION POND Inflow Area = 3.260 ac, 54.29% Impervious, Inflow Depth = 4.21" for 10-yr event Inflow = 23.38 cfs @ 11.96 hrs, Volume= 1.143 of Outflow = 9.09 cfs @ 12.06 hrs, Volume= 1.142 af, Atten= 61 %, Lag= 6.2 min Primary = 9.09 cfs @ 12.06 hrs, Volume= 1.142 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 516.42' @ 12.06 hrs Surf.Area= 8,429 sf Storage= 23,182 cf Plug -Flow detention time= 387.0 min calculated for 1.142 of (100% of inflow) Center -of -Mass det. time= 386.8 min ( 1,173.0 - 786.2 ) 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=9.09 cfs @ 12.06 hrs HW=516.42' (Free Discharge) 1=15" HDPE Out (Inlet Controls 9.09 cfs @ 7.41 fps) 2=48" Standpipe (Passes < 11.20 cfs potential flow) 3=6" Control Orifice (Passes < 1.02 cfs potential flow) =4" Perf. Underdrain (Passes < 0.28 cfs potential flow) =18' Emergency Spillway ( Controls 0.00 cfs) POSTDEV Prepared by {enter your company name here} W Postdev Type 11 24-hr 10-yr Rainfall=5.44" Printed 1/10/2023 Pond 3P: DETENTION POND Hydrograph I I I I I I I I I I I I I 2 8 c s I __i__r__ r ;--r-1','nfl0WTArea'=;3.,26G, �- I I I I I 1 1 1 1 1 1 1 1 1 1 1 P0a'k_ rIeV=01.6.47,` _ ----L--------1----'--- I 1 I I I I I 1 I 1 1 1 I I 1 1 1 I 1 I I I I 1 1 I I 1 1 I I 1 1 1 I 1 I I I 1 1 1 I 1 1 1 I I 1 1 1 I I I I I I I I I I I I I I I I I 1 1 I I I 1 1 1 I 1 1 1 I I 1 1 1 i 1 I I I 1 1 1 I 1 1 1 I I 1 1 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 I I 1 1 1 I 1 1 1 I I 1 1 1 I 1 1 I I 1 1 1 I 1 1 1 I I 1 1 1 I 1 1 I I 1 1 1 I 1 1 1 I I 1 1 1 1 1 1 I 1 1 1 1 I 1 1 1 I I 1 1 1 i 1 1 I 1 I 1 1 1 I I 1 1 1 1 1 I 1 1 1 I 1 1 1 I I 1 1 1 I I I I I I I L__I__J__1__L__L__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 42 44 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (crs) ■ Inflow ■ Primary ❑ Primary Postdev POSTDEV Type // 24-hr 10-yr Rainfall=5.44" Prepared by {enter your company name here} Printed 1/10/2023 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 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 17 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 2.74 cfs @ 11.96 hrs, Volume= 0.128 af, Depth= 3.57" 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 0.310 80 >75% Grass cover, Good, HSG D 0.430 85 Weighted Average, UI Adjusted CN = 83 0.310 72.09% Pervious Area 0.120 27.91 % 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 1 2.74 cfs I ■Runoff Type II 24-hr 10-y!r Rainfall=5.447 Runoff Area=0.430 at Runoff Volume=0.128 of Runoff Depth=3.57" Tc=5.0 milk UI Adjusted CN=83 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 1/10/2023 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 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 19 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 0.73 cfs @ 11.96 hrs, Volume= 0.034 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 0.010 98 Unconnected pavement, HSG D 0.110 80 >75% Grass cover, Good, HSG D 0.120 82 Weighted Average, UI Adjusted CN = 81 0.110 91.67% Pervious Area 0.010 8.33% 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 08 - -- 0.73 0.75 0.7 I I I I I O.65 O.fi 0.55 _-r-------- 0.5 0.45 i- .r 04 LL 0.35 0.3 I I I I I I I I 0.25 0.2 0.15 __r-y_-y_-Y___ 01 0.05 Hydrograph I I I I I I I I I I I I I I I I I I I I _L - vile - 4=yr I I I I I I I I V n --I-1--T--T--r--r--I--I--T--T--r--I--�I-*(-�T--T--T--I - I I I I I I I I I I _I ReinfalLz5.�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 - -- --;- ---II--�tyn4ff_ Mtxnpr:;O.03d4_ f 1__ LL__ I --i #-II'D�7rI� �I .;--neep3I 8,I - -!r --;--;--;--�----;--;WA' Ms*O-QN=81_ I I I I I I I I I I I I I I I I I _-L-J--1--1--L--L--I--J--1--1--L--I--J--1--1--L--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 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 1/10/2023 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=2.830 ac 58.30% Impervious Runoff Depth=5.52" Tc=5.0 min CN=90 Runoff=26.04 cfs 1.302 of Link 2L: PDA 1 Inflow=13.82 cfs 1.681 of Primary=13.82 cfs 1.681 of Pond 3P: DETENTION POND Peak Elev=517.07' Storage=28,902 cf Inflow=29.61 cfs 1.471 of Outflow=10.82 cfs 1.471 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.430 ac 27.91% Impervious Runoff Depth=4.74" Tc=5.0 min UI Adjusted CN=83 Runoff=3.57 cfs 0.170 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=0.120 ac 8.33% Impervious Runoff Depth=4.52" Tc=5.0 min UI Adjusted CN=81 Runoff=0.96 cfs 0.045 of Total Runoff Area = 3.820 ac Runoff Volume = 1.682 of Average Runoff Depth = 5.28" 52.09% Pervious = 1.990 ac 47.91% Impervious = 1.830 ac Postdev POSTDEV Type // 24-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 1/10/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 21 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 26.04 cfs @ 11.96 hrs, Volume= 1.302 af, Depth= 5.52" 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 1.650 98 Unconnected pavement, HSG D 1.180 80 >75% Grass cover, Good, HSG D 2.830 90 Weighted Average 1.180 41.70% Pervious Area 1.650 58.30% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, 28 26.( 26 24 22 I I I I I 20 I I I I 18 16 c 14 M I I I I r r 12 ,0 I I I I 8 I I I I 6 4 I I I I I Subcatchment 1S: DA 1 - Onsite Managed Hydrograph I I I I 1 1 1 1 I I I I I I I I ■ Runo,F 14 cfs 1 I I I I I I I I I --!-- *Ype4k�r-yam I 1 _L__L_J__J__J__1__1__1__L__ L__I_ Rainf 11:*&.691r I I I I I I I I I I I P, �a r� I I I I I I I I I I I I I I I I I I -; I I I I I I I I I I I I I I I I I ROnQf 1t;1 mJ'e_:g1.$02_nf _ tuna#IIIDepth�5.,�2�'-- -I I I I I I I I I I I I I I I I I _ f-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 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 I I I -r--r I I -1--1--1--r--r--r I I �--i--1--r--r-- I 1 1 L _L _I _J _J I I I I I I I I I I I I I I I I I -------------- 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) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 22 Summary for Link 2L: POA 1 Inflow Area = 3.820 ac, 47.91 % Impervious, Inflow Depth > 5.28" for 25-yr event Inflow = 13.82 cfs @ 11.97 hrs, Volume= 1.681 of Primary = 13.82 cfs @ 11.97 hrs, Volume= 1.681 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 -T -I ■ Inflow _L__I__ J__1__ L_J__J__ 1__ L__L_J__ QPfIOB Primary 15 1< , 13.82 c T ;, T1,hf1ow;re�,820 13 / I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 12 / I I I I I I I I I I I I I I I I I I I I I 11 I I I I I I I I I I I I I I I I I I I I I 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 / _1 _L _I _J _1 _L _L _I / I I I I I I I I I I I I I I I I I I I I I '/ __II__ I__ __I __I I __II__ __II___II__ I__I __I __II__ O I I I I I I I I I I I I I I I LL / 6 -I I I I I I I I I I I I I I I I I -y -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 I I 4 / / __I__1__7__r___1__7__r__I__1__7__r__r__I__ I_ J_ 1_ L_ L__I 1__L__I__J__1__L__L__I__ 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 Time (hours) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here) Printed 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 23 Summary for Pond 313: DETENTION POND Inflow Area = 3.260 ac, 54.29% Impervious, Inflow Depth = 5.42" for 25-yr event Inflow = 29.61 cfs @ 11.96 hrs, Volume= 1.471 of Outflow = 10.82 cfs @ 12.06 hrs, Volume= 1.471 af, Atten= 63%, Lag= 6.5 min Primary = 10.82 cfs @ 12.06 hrs, Volume= 1.471 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 517.07' @ 12.07 hrs Surf.Area= 9,120 sf Storage= 28,902 cf Plug -Flow detention time= 320.3 min calculated for 1.470 of (100% of inflow) Center -of -Mass det. time= 320.6 min ( 1,100.0 - 779.4 ) 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=10.71 cfs @ 12.06 hrs HW=517.07' (Free Discharge) 1=15" HDPE Out (Inlet Controls 9.83 cfs @ 8.01 fps) 2=48" Standpipe (Passes < 45.41 cfs potential flow) 3=6" Control Orifice (Passes < 1.28 cfs potential flow) =4" Perf. Underdrain (Passes < 0.30 cfs potential flow) =18' Emergency Spillway (Weir Controls 0.87 cfs @ 0.70 fps) POSTDEV Prepared by {enter your company name here} W Postdev Type 1124-hr25-yr Rainfall=6.69" Printed 1/10/2023 Pond 3P: DETENTION POND Hydrograph fS J--J- L L J-- I J--' L--L I I I I I I I I I I I I I I I I -- - -- --II,- illlnfloW-Al 13260rlac- _� l :POD- F lbV=§-17;' - _ J 1/w�_L_ _J R1__L_//_�L_ I _ or Cf - I I I I I I I I I I I 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--J--L--L--'--J--1--L-I--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__ 7 - - 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 I I I I I I I I I I I I I 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 42 44 Time (hours) Pond 3P: DETENTION POND Stage -Discharge Discharge (crs) ■ Inflow ■ Primary ❑ Primary Postdev POSTDEV Type // 24-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 1/10/2023 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 // 24-hr25-yr Rainfall=6.69" Prepared by {enter your company name here} Printed 1/10/2023 HydroCAD® 9.10 s/n 07054 ©2010 HydroCAD Software Solutions LLC Paoe 26 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 3.57 cfs @ 11.96 hrs, Volume= 0.170 af, Depth= 4.74" 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 0.310 80 >75% Grass cover, Good, HSG D 0.430 85 Weighted Average, UI Adjusted CN = 83 0.310 72.09% Pervious Area 0.120 27.91 % Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (f /ft) (f /sec) (cfs) 5.0 Direct Entry, ,T- 0 2 4 6 8 10 Subcatchment 3S: DA 1 - Offsite Managed Hydrograph I I I I I I I I I I g��II i I I I I I I I I I I I I I I I ■ Runolf type 111 24-hrl 2$-yr I I I I I I I I I I I I I I I I I --I'-- ---Rain#aIIT6:69"' I I I I I I I I I I I I I I I I I I I I I I I I I R4nbff AreI I I O=0.430 alpI I I I I I I I ROn4f(Vg1Lpme=0.170 elf --;--kuneff Depti 4:I1741'- I I I I I I I I I I I I Tc=5.0 tinih I I I UN AIId1NSteo CAN=8$ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 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 46 48 Time (hours) Postdev POSTDEV Type 11 24-hr 25-yr Rainfall= 6.69 " Prepared by {enter your company name here} Printed 1/10/2023 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 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 28 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 0.96 cfs @ 11.96 hrs, Volume= 0.045 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 0.010 98 Unconnected pavement, HSG D 0.110 80 >75% Grass cover, Good, HSG D 0.120 82 Weighted Average, UI Adjusted CN = 81 0.110 91.67% Pervious Area 0.010 8.33% 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 0.96 cfs Type II 24-hr 25-yr Rainfall=6.69" Runoff Area=0.120 ac Runoff Volume=0.045 of Runoff Depth=4.52" 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/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 1/10/2023 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=2.830 ac 58.30% Impervious Runoff Depth=7.71" Tc=5.0 min CN=90 Runoff=35.58 cfs 1.819 of Link 2L: PDA 1 Inflow=36.55 cfs 2.372 of Primary=36.55 cfs 2.372 of Pond 3P: DETENTION POND Peak Elev=517.57' Storage=33,593 cf Inflow=40.63 cfs 2.065 of Outflow=31.44 cfs 2.063 of Subcatchment3S: DA 1 - Offsite Managed Runoff Area=0.430 ac 27.91% Impervious Runoff Depth=6.86" Tc=5.0 min UI Adjusted CN=83 Runoff=5.05 cfs 0.246 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=0.120 ac 8.33% Impervious Runoff Depth=6.61" Tc=5.0 min UI Adjusted CN=81 Runoff=1.37 cfs 0.066 of Total Runoff Area = 3.820 ac Runoff Volume = 2.373 of Average Runoff Depth = 7.46" 52.09% Pervious = 1.990 ac 47.91% Impervious = 1.830 ac Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 30 Summary for Subcatchment 1S: DA 1 - Onsite Managed Runoff = 35.58 cfs @ 11.96 hrs, Volume= 1.819 af, Depth= 7.71" 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 1.180 80 >75% Grass cover, Good, HSG D 2.830 90 Weighted Average 1.180 41.70% Pervious Area 1.650 58.30% Impervious Area 1.650 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f /sec) (cfs) 5.0 Direct Entry, 3636 I I I I I __i __i___I_ --------'- 35.! I I I 34 32 30 28 28 24 �p 22 u I v 3 20 _ I _I _ J _ J , 0 LL 18 16 1412 I 10 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 - -- '-- =11 0 ==2_�JIL f r =Typgf:24-r __ __ __ I_= I I 1 1 Inbf-Ate2.830 ap 10npl- = -I'I,- It(rinofF Deptlr7.17 I I I I I I I I I I I I I I I I I ___-YYYI ____-YYYI ____-TrTI ____-rrYI ____-rIrY ____-IIII -__YrI _-_T#rrI -Y _r__r__I_____�__Y__Y__r__r__r__I___,__-__Y__r__Irr 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 // 24-hr 100-yr Rainfall=8.92- Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 31 Summary for Link 2L: POA 7 Inflow Area = 3.820 ac, 47.91 % Impervious, Inflow Depth > 7.45" for 100-yr event Inflow = 36.55 cfs @ 12.00 hrs, Volume= 2.372 of Primary = 36.55 cfs @ 12.00 hrs, Volume= 2.372 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 _1__7__r r--r ,__r__r__r_ J__ r__ r 7__ r__r__�__ E InIM 40 � --'--J-- --`--I__�--J--`--`--'--J--`--`--'--J--J--`--`--'-- ■Pnmary 36 '',' , , 36.55 ;- ;- VIJ �I�yII oW;Al 1 '3.' 2G a� 34 ,' --- I 32 1 1 ____________________ 30 i' 1 1 _J__J__1__L_ 1 1 1 1 IL1 1 1 1 __J__L__I__J__J__L__L__I__J__1L_J__J__1L__L28 _I__ I 1 _A _L _I _J _J _1 _L _I _J _1 _L 28 24 ' 1 __i__r__7__r_ 1 1 1 1 1 1 __r__r__I__1__r__r__r__i__�__r__r__i__�__r__r__r__i__ � u 22 ' 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 20 _J------� - ----�----J1--J1__L__I-----J-- --I-- �__J----�--I---- 0 ' 1 1 1 1 1 _ 18 LL ' ' - 1--J--1--L- --J--L--I--J--J--1--L--1--J--1--L- I--J--1--L--`-J-- 16 ' .14 i ' I I I I -I _, _+ -r I I I I I I I I I I I I I I I I I _, -r -I -I _y 12 ' I __-__r__r 1 ___r__r_____r__r__r_-___i__�__7__r__r__i__ 10 --------- -------------- ----------- -------------- g' 1 1 1 1 1 1 1 6 ' 1 1 1 1 1 1 4 Time (hours) Postdev POSTDEV Type/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here) Printed 1/10/2023 HvdroCAD@ 9.10 s/n 07054 @ 2010 HvdroCAD Software Solutions LLC Paae 32 Summary for Pond 313: DETENTION POND Inflow Area = 3.260 ac, 54.29% Impervious, Inflow Depth = 7.60" for 100-yr event Inflow = 40.63 cfs @ 11.96 hrs, Volume= 2.065 of Outflow = 31.44 cfs @ 12.01 hrs, Volume= 2.063 af, Atten= 23%, Lag= 3.2 min Primary = 31.44 cfs @ 12.01 hrs, Volume= 2.063 of Routing by Stor-Ind method, Time Span= 0.00-48.00 hrs, dt= 0.03 hrs Peak Elev= 517.57' @ 12.01 hrs Surf.Area= 9,649 sf Storage= 33,593 cf Plug -Flow detention time= 250.2 min calculated for 2.062 of (100% of inflow) Center -of -Mass det. time= 250.5 min ( 1,021.1 - 770.6 ) 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=30.77 cfs @ 12.01 hrs HW=517.56' (Free Discharge) 1=15" HDPE Out (Inlet Controls 10.36 cfs @ 8.45 fps) 2=48" Standpipe (Passes < 75.59 cfs potential flow) 3=6" Control Orifice (Passes < 1.44 cfs potential flow) =4" Perf. Underdrain (Passes < 0.32 cfs potential flow) =18' Emergency Spillway (Weir Controls 20.40 cfs @ 2.02 fps) POSTDEV Prepared by {enter your company name here} Postdev Type/1 24-hr 100-yr Rainfall=8.92rr Printed 1/10/2023 Pond 3P: DETENTION POND Hydrograph -I _y _y - I _I _y _} _F _I _y _♦ _f _F _I I I -I -I __I__ J I -L L I -I -J L I -I -I L -I -I JI - I -I 40.63 cfs J 1 L L 42 - --- _y__---r--, 40 38 __1__J-- 36 34 - - -'-- 31.44 32 __I__J_ 30 28 26 v 24 1 _r 3 22 _ _J__L__L- � ILL 20 / ----y--+__�_ 18 / 18 14 12 10 8 1 1 -I -1 -T -r 6 1 __1__1 W __ __ ____ __ __ ____ __ __ __ r } - - - - �nfiloartkrei�3:2Ga------a�- - ------------------------------------ I I I I I I I I --1L--;POW r:1e4=5174T`= i otag =;;5931Fef _ I _y _y _f _F _I I I I I I I I I I 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__L_J__J__1__L__L_I__ I I I I I I I I I I I I I I I I I 1 1 1 1 1 1 1 I 1 1 1 I I 1 1 I I 1 1 I I I 1 -T -r -I -T -r -I -1 -T -r -r -I I I I I I I 1 1 I I I 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) ■ Inflow ■ Pdmary ❑ Primary Postdev POSTDEV Type // 24-hr 100-yr Rainfall=8.92rr Prepared by {enter your company name here} Printed 1/10/2023 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 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 35 Summary for Subcatchment 3S: DA 1 - Offsite Managed Runoff = 5.05 cfs @ 11.96 hrs, Volume= 0.246 af, Depth= 6.86" 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 0.310 80 >75% Grass cover, Good, HSG D 0.430 85 Weighted Average, UI Adjusted CN = 83 0.310 72.09% Pervious Area 0.120 27.91% Impervious Area 0.120 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (f /ft) (f /sec) (cfs) 5.0 Direct Entry, Subcatchment 3S: DA 1 - Offsite Managed Hydrograph I I I I I I I I I I I I I I I I S��SIII I I I I I I I I I I I I I I I I ■ Runoff 1--L--L--L - -I- - - III Yype III124-Mr 100-yIr RIai nfal_h8_ .19_ _2"' _I _ _ _J _1 _L _L _L _I _I_ RUnbfFl Areti=0.430 alp r4On6f(Vg1Lpm6=0.240 elf + Runoff+Depth�6.1661 �• I I I I I I I I I I I I I I �IIr/�, Itni Iy^ 5. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II II 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 1/10/2023 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/1 24-hr 100-yr Rainfall=8.92" Prepared by {enter your company name here} Printed 1/10/2023 HvdroCAD® 9.10 s/n 07054 ©2010 HvdroCAD Software Solutions LLC Paae 37 Summary for Subcatchment 5S: DA 1 - Offsite Un-Managed Runoff = 1.37 cfs @ 11.96 hrs, Volume= 0.066 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 0.010 98 Unconnected pavement, HSG D 0.110 80 >75% Grass cover, Good, HSG D 0.120 82 Weighted Average, UI Adjusted CN = 81 0.110 91.67% Pervious Area 0.010 8.33% 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 1.37 cfs Type II 24-hr 100-y,r Rainfall=8.92" Runoff Area=0.120 ad Runoff Volume=0.066 of Runoff Depth=6.617 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 Channel Protection: Energy Balance Equation with Run-on for POA 1 Forest Lakes Self Storage 1 Yr, 24 Hr Storm Comparison Q 1post s Q i Pre, Site ((RV l Pre, Site)/(RV 1 Post site))(I.F.) + Q i Pre, offsite ((RV i Pre, omiwy(RV i Posl, of site)) LF. = 0.8 when LOD > 1 ac, I.F.=0.9 when LOD 5 1 ac, I.F. = 1.0 when predev site is fully forested PreDev Site Fully Forested? = no LF. = 0.8 Limits of Disturbance = 3.29 ac Onsite offsite Pre Dev Area Onsite = 2.86 ac Pre Dev DA Offsite = 0.42 ac Post Dev Area Onsite = 3.27 ac Post Dev DA OtiSite = 0.55 ac Q i Pre, site = 3.80 cfs Q 1 Pre, orate = 0.76 cfs RV i Pre, site = 0.294 of RV 1 Pre, office = 0.058 of RV i Post, Site = 0.512 of IRV 1 Post office = 0.064 of Regulatory Maximum Postdev 1-yr Flow Rate Max Qlposst < 2.43 cfs Achieved Design Postdev 1-yr Flow Rate Design Qlpost = 1.53 cfs 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 Q10we = Max Q10Post = 12.02 cfs Achieved Design Postdev 10-yr Flow Rate Design Quipost = 11.14 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 o a z %> U`. y Hd E C4 Zu -r X Kwe zy Ez w d UE z0 O m a 2 a Yn U Q of a a a 2 ci Uwn co 1 2 31 4(ac 5 6 8g(c9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 ft) On 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 131-313 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 131-313 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 d5o in Depth in A2 9 1 10.5 18 1 1.5 1 4.5 0.5 1 6 9 BO 9 1 10.5 18 1 1.5 1 4.5 0.5 1 6 9 BO 6 1 6.67 8 1 0.67 1 2 0.5 1 6 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 ° 1 DB R. \ 40 ACCESS EASEM�NT �� , De 11 nzG GRAPH NRpNIA TETFPNDNE 6 _- • a� . � �_ \ \ TELEEASEMENT J B PG .95 /l L � `.'.'.` �.''' `� • � I oe zeo vG loz r \ •r • r • r ' •� '�t A�CS ' ••• \ • V' D A MEN 4 ••• • 1' • •.I'.•. •�..•. •.5'SLCYEk \ \ ••r ••�• r • / IB' CO IRUCIIW EASEMEN- { D 352fi�0] ti.. . . . . . . . .....�;.;.;.; .,.;.j.;.i.::...:.a. r•.'.•.'r'r....':::1:�':: ' .�.•r;.:r;....r....;.:r;r...�•:�.•r`r•.-r�:•.`.•r`r•.�r•.•�.•r`r•.-r•.••••• •.•f`:•C`' :`7• • � / .�•• ':/• •:/• :.: `: / • '•'•'•'•'•'•'•'•' r••'•••'r••'.'r �• •`•'r f�' :• VARI LE'M"EHT SEWER •• •`y/• r• •'' r'.- EASEMENT D6 ,C94 -G-MM 1 \ \ \ q Scale: 1"=6 ' IS' 1EIEPW EASEMENT ONSITE LAND COVER: DISTURBED AREA = 3.29 AC IMPERVIOUS = 0.00 AC TURF = 3.29 AC WOODS = 0.00 AC 60 120 N 180 FOREST LAKES SELF STORAGE POSTDEV VRRM MAP \ I- ACCESS EASEM�},\i ` Tom_ ` ✓ DO 1 DO � \ ••.°aaaaa '�;:.;`,• � aaaaa '• IIIIaa \ \ •-: aaaa°�a° .'...... � -' • aaaa aaaaaaaaa \ \ .: aIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIII as°aaaaaa °aa '' IIIIIIIIIIII II IIIIIIIIIIIIII IIII \ \ \ \ add0 ddaddaddaddaa C f '.. a o aaaa oa�`aoaaoaaoaaoaaoa • aaa Sa:raaaaaaaacaaaaaaaaaaaaa ... aaaaaaa �# oaaooaooa000 � \ \ �� \ '. a°aaaaa°o °d°daadda a a aaaaaaaaa - aaaa aaa aaa°o aIIaaaaaIIaaq'ill aaaIIaaaaaIIaa aaaaaaa aaaaaaaaz IIIIIIIIIIIIIIIIII --- aaaaaaaaz IIIIIIIIIIIIIIIIII ddadaddadt • aaa a°a° a aaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaao •: °II°a II aaaaaaaaaaaaaaaaaaaaaaaaaaaaIIaaaaaaaaaaaao .•:•:•:•:•:• aaa a a�II°a°II°II°a°II°II°a°II°IIaa°a°II°a°II°IIaa°a°IIaa°a°II$ \ a as aaaaEwaaaaaaaaaaaoaaaaaoaaaaaoaaaaaoaaaaaoa :•: •: •:•: •:`: •: •: •: •:•:•�': •: : a as d d��yyaddadaddaddaddaddaddaaIId \ _ . •. •. . •. •. •. •. •. •. . •. •. •.' aaaaa a aaaaaaaaaaaaaaaaaaaaaaaIIIIaaaaIIIIaaaaIIIIaaa as .•.F •�••-..... •.`--••---•-•.`--• IIIIIIIIIIIIIIa IIaIIIIIIIIIIaIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIa�IIa� \ � aaaaaaaaa a da°a°a°a°a°a°a°a°a°a°a°a°a°a°a°a°a°a°a�°o aaa°a°aaa°a° aaadaaaaaaaaaaaaaaaa. o _.•._.•._.•1 .•.. ...•. °ao azao aaaaaaaaaaaaaaIIa°aaa°aaaaaaaaaaaaaaaaaaaaaaaaaaa° • �•' •• oaaoaaoaaoa�oaaoaaoaaoaa �.�.�.�.�.�..�.•.�.• .. _ aaaa°aaaaa°aaaaa°d°aaa°d°aaaa°aaa°d°aaa°d°aaa°d°o ... �.'.'.'.'.'.'� aooaooaooa0000 aaaaaaaaz •;• �;•; ; a aaaaaaaaaaaaaaa°z�aaaaaaaaa \ aaoaaoaaoaaooaoo aaaaaaz . II IIIIaIIIIaIIIIaIIIIaaIIaaIIaaaaIIaaIIaa ...... aaaaaaaaaaaaaaaaaa �ppaoaaoz � i •;f a IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII \ .:.•\•'•,•;•;•;•; odaadaadaadaadaadaa aaaaaz ..� .•.... o aoaooa000000000000o aaaaa •'�. a dIIddIIddIIddddddddddddddddt ' �` ' ' ' '�- ' - asasasasasasasasasaaaaaaaaaaaaaaaaaaaaaanaaaaaaaa° •r.•.•.•.•.. • r. • .•.•...... a aaIIaaaaaIIaaaaaIIaaaaaIIaaaaaIIaaaaaIIaapaa�IIaaaaaIIo � :::' `r:.. �: •' -' . �': - .:� :': -' :'R a aaaaaaaa0 adadaaadadadadadadadadaaadaaodaaaaada0 o aaaaaaaaaaaaaaaaaa aaaaaaz ..� . ... _ ' '..a aaaa aaadaaaaaaaaaaaaaaa '•' � ; aaa aaaaaaaaaaaop.�oaaoaaoz e. , a II�IIIIIIIIII000000IIz]IIIIIIIIIIIIIIIIII •a ..•.`.• .•.•. •,,�.•.. ooaoaaooaooar� aaooaoaaoz • .: g IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIa� \ \ 1 dada• a aaaaaa 15 KEASE 108 MFN ] \ \ DB IDBV PC I W \ 15' 1ElFPNONE FISFHENi \ \ \ DO 111] PG ] 6 \ \ ff♦+.ftff♦ YA t sr�s Y Y ,r• - Y Y Y �♦ r a•� �� i� —� . :. r♦rr♦ a♦vn r�� r,sr t,rr arrrr YYf♦�x irrr-:. .rrsr�i,'n.. rrr sr tt♦ts-t,r. srtsrr srr,Y ♦t♦f ♦ff♦ f�rr ♦tst'♦at♦tes� ♦Y,rntrt,t Y-. srt ;rtvrt♦♦ � 'r Y,r n,rY„nrl ♦.. �atvro trl rt♦,t rrt♦r.� ...:. 1•rrr Yrr' ♦♦. Yv��w Yrw, rttttq�t Y♦tt� IIIIIIMM - t. rt trnc♦♦♦ rtr r�'♦xr sr, rr rtve„aY r f, Y:�i rt♦r� .vw rw.,,rtt Yr♦tts ill A '3`rttil'�A•-_�•'w'r_-� r�7� �� ti ONSITE LAND COVER: DISTURBED AREA = 3.29 AC IMPERVIOUS = 1.78 AC MANAGED TURF = 1.51 AC WOODS = 0.00 AC 60 120 N 180 Dm Mrylnlam—ffm [xan Mernaerxw Davemcmeaf mmWbnmsnreamheee [a"yg1 BMPRimEaind3ptlYOlbs 03013 Ua BMPR lords aM Sp M=Ims PmjeR xame: Forezt lakes Self Ron M@: 11/2B/2o22 BMY DeKn spe[ihauliwu tisf. . Site Information Post -Development Project (Treatment Volume and Loads) UM cover (aneal AS iD &bik CSoile Ds.ile e:r/O,e mPeal- Hamm, ed M—v pen �.m.eam land Dme rvml+wal. d�em.aea,emamm' ssl y mdm EemoweQ/maregM ]51 m rviemcem lamq 1>e ]]B 3]9 nns ants ammlipreneel 43 wme,—ff)iEMC 1.m m.liEMC(MmyU m¢ee(W—M 0.26 11 m/D 1.aG Waa 114/ave/yr) OA] PIIM mnn�m.l 6.m 3.0 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. IMPER IAANAGED TURF ARM Ia[) 0.00 0.00 0.00 0.00 0.00 OK. MANAGED TURF AREA TREATED (x) 0.00 0.00 0.00 0.00 O.00 OK. AREA CHECK OK OK. OK. OK - Site Treatment Volume (k3) 7,509 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 REDUCTIDAVARO 0 0 0 0 LE FOR RE OV L (11b/ TP LOADAVAINBLE FOR REMOVAL Qb/yr . 0.00 O.W 0.00 � 0.00 O.M 0.00 TP WAD REDUCnONACHIEVED pb/yrl 0.00 aw 0.00 0.00 0.00 0.00 TP LOAD REMAINING IIb/yr) 0.00 0.00 DUO 0.00 0.00 DUO PUMOGEN WAD REDUCTION ACHIEVED Qb/yr 0.00 0.00 0.00 0.00 0.00 0.DO Total Phosphorus FINAL POST -DEVELOPMENT TP LOAD (lb/yr)) 4.72 TP LOAD REDUCTION REQUIRED pb/yrl 3.37 1P WADREDUCTION AOIIFVED Ib/yr) 0.00 lP LOAD REMAINING Qb/yr):1 4.22 REMAINING TP LOAD REDUCTION REQUIRED (Ib/yr): 3.37 Total Nitrogen (For Information Purposes) POST -DEVELOPMENT LOAD IIb/yr) 1 33.75 NnnOGEN LOAD REDUCTION ACHIEVED (Ib/yr) am REMAINING POST -DEVELOPMENT NITRWEN LOAD (Ib/yr) 33.75 WgMa Runon RMumon Who! Vda Imwt DED Virglnla RuroM xedunlon Mellmd New DmwlopmeM COmdllwW,Spmwklwet - Vemlon 3.D RMPOesign 5pe[ifrcodons list . SNe Summary Pmlert isle: Forest lake 5 fSbra,e Oate: M%93 Total Rainfall= 43 inches Sibe land Cover Summary R mils BSons CStlls DSons Totals %of Total ForeM/Open(acres) 0.00 0.00 0M 0.00 O.W O Managed Tudlaorm) 0.00I 1 0.. 1.51 1 1.51 Vfi Impervous Carer (acres) O.aO 0.00 0.. 1.19 1.78 sa 3.i9 Wo SNe Tv and land Cover NMrient lads xe M O.63 TrealmeM Valunm 7'5a9 Tl Wad(Ib/yr) 0.R Tx Wad (Ib/n) T 1 TP Wad Redunion Required(I3.3] Sile Compliance Summary Total Ruud Volume Redudion(W) 0 Total TP Wad Redudlon R[Meved pbIWI 000 Tmal TN Wad Reduction F ftwml pbIWI 0.00 Remaining Pon Development TP Wad (Ib/yr) -72 Remaining TP Wad Reduction(lb/yr) a..Require, OAR DAB OAC DAD OA.E Toral Wren/open(aarm) D.m D.m D.DD a.aD a.Do D.aD Managed Tud(wFm) D.W D.N 11 O.DO O.aD D.D] O.aD Impervious Wver(mrmd D.W D.N I O.M Om 0.. O.DD Total Area(2—) o.001 D.. ID.aD D.00 D.ao ao0 Drained, Area Compliance Summary OAA OAB OAC DA.D OAE Total TP Lead Reduced! Ib/ r D.N D.N D.OD O.DO D.OD O.N TN Wad R oduced(lb/yr) Dm Dm 0... 1 O.OD D.Oa Dm l,e roman 1 ,e ratorm 1 ] ewdam Target Rainfall Event lin) 1 3.00 1 3.B0 1 5.W Drainage Fress RVBCN Ommage AreaA DnlnageAmB mm-,¢AmmC Dram,e Area Drainage men w o 0 o a o RRR o a o a D 1-year Mum period RV mna orAn) oCo 000 0.0] ooa oCo et (vain( oCo oN O.W oN oCo HaalunM o 0 0 0 0 ]-year Mum pedod mM(v+cn) oCo oN O.W oN oCo etm-11) oCo oN O.W oN oCo HaalunM o 0 0 0 0 W year return period mM NeA.) oCo oN O.W oN oCo M m-11) oCo oN O.W oN oCo xaalunM o 0 0 0 0 Summery Print Independent Reports: Excerpt from NRCS Soils Report NOAA Precipitation Report M'7WN W 743' N 3 Hydrologic Soil Group —Albemarle County, Virginia 3 (Forest Lakes Self Storage) w a � M'TWN F4 v a 74T N 724M ] 4550 724510 724M n4TU TMT.ID n4 Tt 10 T240I0 ]�i0fl ]�[00 3 3 Map Smle: 1:2,930 iFprinted on A larxwape (11" x 8.5") shed p K N Wars 0 40 so 100 290 A0 100 3D 400 B00 Map prCW": Web MeraMr Co coordinabs: WaM Edge ti s: U1M Zone 17N WGS84 USDA Natural Resources Web Soil Survey 6/30/2022 Om Conservation Service National Cooperative Soil Survey Page 1 of 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•r.,,,,, Latitude: 36evatio, Longitude:-76.4353° Elevation: 521.79 ft*' E a 3 W " source: ESRI Maps '�� j "" 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)+ Average recurrence interval (years) Duration + z s +o zs so 1 100 oo zoo soo +000 5-min (0.3 6-0387) (0.3777--0.462) (0.442-0.542) (0.496-0.609) (0.557-0685) (0.603-0 78) (0.646-0 803) (0.684-0858) (0.730-0 928) (0.765-0.985) +0-min (0.504-0618) (0.6 3-0739) (0.707-0.8) 6 (0.7930975) (0.8899109) (0.960a.19) (1.03i27) (1.09-21336) (1. 5-3147) (1.211.4.55) +5-min (0.6 0-0..773) (0.758-0929) (0. 955-11.10) 1 (1.M1.23) 1 (113-21639) 1 (1.22-31.50) 1 (1.0-1.61) 1 (1.37--1.72)1 (1. 5-OL85) 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) (1.99-2.47) (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) (1.89-2.33) (2.2�73) (2.8-3..07) (2.74-3940) (2.91�75) (3.32-422) (3.58461) 2.18 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. 5-4689) (4.24--5.61) (46 5-6.23) 2.79 4.27 3-hr (1.38-1.79) (1.67-2017) (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 +2-hr (2.21206) (2.67-3.45) (3.31�60) (3.91�08) (4.715z16) (5A1�13) (6148.19) (6.929535) (805-111.1) (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) (6.82856) (77 8-9.95) 1A) (8.82-12 (10.33.5) (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) (7.389?08) (8. 2- 0.4) (9.53-111.9) (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-t7..88) (7.889.57) (9. 0-11.0) (102- 2.5) (11414.2) (132-16.6) (1476- 8.7) 7-day (4.225A6) (5. 9-6.09) (6.35--74.61) (7.37 8885) (8.8210.6) (10.00-12.1) (11 2?13.7) (125-15.4) (14.3-18.0) (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) 6.88 8.20 20 dey (64 3 39) (7.678 4.81) (9.2-110.6) (10.5 2.1) (121314.0) (13.4-15.5) (1476.0.1) (16.0- 8.8) (17.7---21.0) (19.0. 2.8) 30 dey (7939.01) (94 0- 0.7) (111' 2.6) (12.414.1) (141--16.0) (15.3-17.5) (16.5 8.9) (17.7---20.4) (19?2-22.3) (20.323.7) 4s-day (9.9411.2) 1 (117?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?9-23.8) (22?5-25.8) (23.6-27.3) 60-day 2.2 (117 3.1) (13.8-1-5.4) (15.9--18.7) (1740.5) (19.421.8) (209?0.4) (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 Atlas 14 document for more information. Back to Top PF graphical