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HomeMy WebLinkAboutWPO201800078 Approval - County 2020-01-06 (2)Keswick Hall Spa WPO 201800078 COUNTY OF ALBEMARLE, VIR+GINIA V SMP DESIGN CALCULATIONS & NARRATIVE OCTOBER 22, 2018 REVISED: FEBRUARY 15, 2019 JANUARY f, 2020 TIMMONS GROUP YOUR VISfOM ACHIEVED THROUGH OURS. Prepared by: Craig Kotarski, PE Timmons Group 608 Preston Ave, Suite 200 Charlottesville, VA 22903 434.327.1688 1- Or Y , YLJ� U CRATG w J. x(-rARSK1 Lic. No. 040204850' APPROVED by the Albemarle County Community Development Department Date 05/06/2020 File WP02oi800078 - Amendment i Table of Contents Section Title Project Narrative 2 Pipe and Inlet Computations Virginia Runoff Reduction Method Worksheet Summary 4 Pre -Developed HydroCAD Calculations 5 Post -Developed HydroCAD Calculations 6 Nutrient Credit Availabil"i Letter Project Narrative: This project includes the demolition of an existing parking spaces and garden area, construction of a spa facility, parking and associated utilities. Erosion & Sediment Control Limits of Disturbance is 2.60. An area of 2.02 acres was used for water quality and quantity calculations. Water Quality Compliance: The disturbed area of 2.02 acres was used for the water quality analysis. In the proposed condition there will be 0.94 acres of managed turf, 1.08 acres of impervious cover. Approximately 0,55 lblyr of phosphorus shall be removed through the installation of permeable pavement. A total of 1.09 lb/yr have been previously purchased. This plan now proposes an excess water quality treatment of 0.36 lb/yr. Water Quantity Compliance: Stormwater Quantity requirements for analysis point 1 will utilize a CMP detention system located within the parking area to meet all stormwater quantity requirements for this drainage area. 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Runoff Reduction volume end TP INV Drainage Mea s v[ny[i 10x VOWM, WPNrt IR i16 O.a a 00 c O 0 O OO E ll6 ON z.� n 11y 4WivW Re-1,01N nCH11Vrn ICI 0.56 N00 Ow PR Ow P55 rn taw REreriHlHG MWryj HlrnoGw senoRwuEncw •Excvm Ogh+l Total Phosphorus rx'a p5r-t(Ve,.oaar{Hr ro •er0 {Ins RJB _ i�wYe RrqulR[O [Wiwi d�a Ter [o {ol[y OSf . w [v�RWtx: MI—NInGMI—D REouaTcnr REWIRED Pemr Total N UNo (Far Iniormetion Purposes) dolWml � v «+M nrrm RarrtaGC Er Eau Nh.l rxmwnmc rest orr palsy RunoH Volume and Curve Number Calculations Emer design slnrm rainfall depms (In)! 1-year— x-year— M—, amrm . r,w.,[a..mvmwon+moef n j •Heresixe ,I n,, il lhn,.p—iy AN— .ad a.mrMl—r w^vfma.M�wa[r 5�in�r sl =,^ b^•fat'If....,,y p..iewmap�udnwgan r.4.E.,wwl n�,.eer.al.lw wn�y w. e��.y. emr�Fwnio-_wwm^..w:d In r.di exr aae ma.a la me mood naer mmy.,»eanrwaml.aa a.m e<araa•.,n. eaarav ads wa.rr,.M^,ne c� sn aaeda,<laa.aa� ma^�e aT>a e. ea.n mnn.r. 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Mj wHh no ftr f FWdyrslan• S.dy f.k � RVa, —,hn,yprBMdndr! whh RemH Red-i.e. 11-4 'Sve A'nvs n6am oraiu Area [ r.^ma.a-vad.mned.vmar�ad .v.a a,ml sale Ro.ao no.m calls sills ,.w! ax nova —_ — Iwmr.arcar.,^. a n ^... raameea aua eau w I om T Ive vac CHloi a- e��m.m x so- _ HVo... f+ti.y ...in.fl wnh ne-,-W Rrdurnea', 6Av 0lA f110 RVryruterrhrrinrM with RemH Redenlvn• .u, R.ap AdjuetrA CH• 0 a •See Nnus o6oye eralna)te ArNO ASeih BSolh LSells �Shcy am fw•nlV.W Fpe�,Yeen spirrurea-�w,yoe�ue opo [veer amr.dRer�and C raardmn- "..,,m+a a=mdwa.Aaa�r a.�a��rar; t^aa •�,.d,�n. m a.aa� uvn eve t RYq,y,�p jrmreNnfiorM1! with no ReMf RMxnlen• Rv� fowpsur am Rh numfF xedunlon• ap El AdJinred [N' •SR rvafn o6aw "a,, f weebefimN wllhnaf ." RVa•..q•, p,eyrsm+ -N whh fh 0 a t a d � c � � C o V C p � x m o f � � A OG v J N a 0 � m o 3 0 c � H m M N C] j o ro m a rb M i Q C o O o O m � a v a ro V � a ro m 72 ro 7 a CL n a cc 2 .c. ro w 0 m a a10 0I0 PPIPg P 0!CoA 0Irlr ❑ I {L I L O I 0 m N m 0. n a 3 3 m m r \ / I §|/ / ! LP -4;�� - �� } « § §� ; � In. § � i » 7 a } ■ � > � - � - 2 � 2 2 � ] s p e !p e a @ G u » 2 [ 2 [ 8 0 � ■ t ; o � k [ E ( !rA 7 - E / _ k M. C \ � � \ (gr _ k \ \ TL - ! % _ 96 _ JJ f { fL 10 / ! I f 0 w m M / go � \E\ � � � § � n ; K 3 2 n� ±E o» CL }/4 8e@ \ \ \ @ 8 @ E !§ § � \J} CD o » 12. \ R ( 0 E2 ( $� _ k \k aq �| §/ 0 k} _ / ƒ / M 0 Q61 e ; f a } (\� • § § § _ � ■ 3 � � _ � - f 3 § » ! n� \(�Q 0 °� � -2E �&2 K K K \ \ ( 5 !§ fg � (7§ � ;} ? � \/ 0 cr �\ \ k / ! I f 0 w _ _ / ) E / | m - ; 2 - - � M � ƒ , P = » � n� ±E o» }/ L 8 e@ g@@ e \ \ \ @ 8 @ E !§ § � \J} CD o » 12. \ R ( 0 E2 k \ C, 0 ® [ § k \k aq �| §/ 0 k} }!( - -4 / / � ) / M 0 e ; o a\ } ( m • § § d 0 ( ( . / � 2 - - 2 � 0. » ! n� � \(� e ° 8 7 S a f )@ � -2E �&2 K K K \ \ ( .5 !§ fg � (7§ � §�! (� ° » k\� ;} o � ( Q} / � \/ 0 cr R\ \ k / ! ( \ k ! CL 2 s � » E m § § = m } 2 ` & / } ; 7 § k , ❑ fn � N Ww O �l 6Ni Sn P W N N O m [G Eo �l Oa z; A W N-4d-­ T ff� tr A W N as a m n n n o o a o apn� n�pa o s O 'fig=off W�a �, m m g m � �g � a Q 6 mjc sz3�49 6 m .» 3� m S ` tm w � - m n' aQ- m2 8- ES ❑�cn ?� c 3 v=.gmlit 0 m so3 m 3 R, �R �a f sm � aw A � N w �� g �m � 7 � - 3 3 $ � ` o a g 3 w 'o m a � m n w 4h n W o o � 3 a 9g - � % 3 6 W g E SECTION 4 PRE -DEVELOPED HYDROCA❑ CALCULATIONS 4S 13L Pre Area 1-1 (Offsite) Areas Combined (1-1 + 1-2) 12S Pre Area 1-2 (Onsite) �Sub�at Reach On Link Routing Diagram for Keswick Ha11_5pa_Analysis Points 1 (PRE) Prepared by Timmons Group, Printed 1/6/2020 I—Hyd-cAm 10.00-20 sin 08663 © 2017 HydroCAD Software Solutions LLC Keswick Hall_Spa_Analysis Points 1 (PRE) Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatch ment-nu mbers) 0.780 83 VRRM SPREADSHEET D.A. A (4S) 2.020 87 VRRM SPREADSHEET D.A. B (12S) 2.800 86 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (PRE) Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAQ Software Solutions LLC Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 0.000 HSG a 2.800 Other 4S, 12S 2.800 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (PRE) Prepared by Timmons Group HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Printed 1/6/2020 Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 0.000 0.000 0.000 0.780 0.780 VRRM SPREADSHEET D.A. A 4S 0.000 0.000 0.000 0.000 2.020 2.020 VRRM SPREADSHEET D.A. B 12 S 0.000 0.000 0.000 0.000 2.800 2.800 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (PRE) Type it 24-hr 1-YR Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 5 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method Subcatchment4S: Pre Areal -1 (Qffsite) Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>1.38" Tc=7.0 min CN=83 Runoff=1.83 cfs 0.090 of Subcatchment12S: Pre Area 1-2 (0nsite) Runoff Area=2.020 ac 0.00% Impervious Runoff Depth>1.67" Tc=7.0 min CN=87 Runoff=5.65 cfs 0.281 of Link 13L: Areas Combi ned (1 -1 + 1-2) Inflow=7.48 cfs 0.370 of Primary=7.48 cfs 0.370 of Total Runoff Area = 2.800 ac Runoff Volume = 0.370 of Average Runoff Depth = 1.59" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (PRE) Type II 24-hr 1-YR Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 4S: Pre Area 1-1 (Offsite) Runoff = 1.83 cfs @ 11.99 hrs, Volume= 0.090 af, Depths 1.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=2.92" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, 2 Subcatchment4S: Pre Area 1-1 (affsite) Hydrograph ❑ Runoff Type II 24-hr 1-YR Rainfall=2.92" Runoff Area=0.780 ac IZT_TiT�ii M16 .. -I,-:�31Xrk1111M, i Runoff ❑epth>1.38" U. 1 Tc=7.0 min a 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (PRE) Type II 24-hr 1-YR Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment 12S: Pre Area 1-2 (Dnsite) Runoff = 5.65 cfs @ 11.98 hrs, Volume= 0.281 af, Depths 1.67" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-YR Rainfall=2.92" Area (ac) CN Description 2.020 87 VRRM SPREADSHEET D.A. B 2.020 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment 12S: Pre Area 1-2 (Dnsite) Hydrograph ❑ Runoff 5 56 cfs Type II 24-hr 5- 1-YR Rainfall=2.92" Runoff Area=2.020 ac 4 Runoff Volume=0.281 of Runoff Cepth>1.67" 3LL Tc=7.0 min CN=87 0 1 2 3 4 5 6 7 8 9 14 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1l 24-hr 1-YR Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCADO IO.00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 8 Summary for Link 13L: Areas Combined (1-1 + 1-2) Inflow Area = 2.800 ac, 0.00% Impervious, Inflow Depth > 1.59" for 1-YR event Inflow = 7.48 cfs @ 11.98 hrs, Volume= 0.370 of Primary = 7.48 cfs @ 11.98 hrs, Volume= 0.370 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs N 3 0 LL Link 13L: Areas Combined (1-1 + 1-2) Hydrograph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 3 1Intlflw C3 Primary Keswick Hall_Spa_Analysis Points 1 (PRE) Type it 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 9 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method Subcatchment4S: Pre Areal -1 (Qffsite) Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>1.89" Tc=7.0 min CN=83 Runoff=2.49 cfs 0.123 of Subcatchment12S: Pre Area 1-2 (0nsite) Runoff Area=2.020 ac 0.00% Impervious Runoff Depth>2.22" Tc=7.0 min CN=87 Runoff=7.43 cfs 0.373 of Link 13L: Areas Combi ned (1 -1 + 1-2) Inflow=9,91 cfs 0.496 of Primary=9.91 cfs 0.496 of Total Runoff Area = 2.800 ac Runoff Volume = 0.496 of Average Runoff Depth = 2.12" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (PRE) Type !l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 4S: Pre Area 1-1 (Offsite) Runoff = 2.49 cfs @ 11.98 hrs, Volume= 0.123 af, Depths 1.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=3.54" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment4S: Pre Area 1-1 (affsite) Hydrograph ❑ Runoff Type II 24-hr 2-YR Rainfall=3.54" s■ I■�:21TiT�MI1 -Z?Ti��iAvIs1 . i[�'iT:�311iL+Mi Runoff Depth>1.89" LL Tc=7.0 min 11 1 11/1 CN=83 0 1 2 3 4 5 6 7 8 9 1ff 77 72 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (PRE) Type !l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 11 Summary for Subcatchment 12S: Pre Area 1-2 (Dnsite) Runoff = 7.43 cfs @ 11.98 hrs, Volume= 0.373 af, Depths 2.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=3.54" Area (ac) CN Description 2.020 87 VRRM SPREADSHEET D.A. B 2.020 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment 12S: Pre Area 1-2 (Dnsite) Hydrograph 8 7 43 crs Type II 24-hr 2-YR Rainfall=3.54" 5 Runoff Area=2.020 ac 5 Runoff Volume=0.373 of Runoff Depth>2.22" 4LL Tc=7.0 min 3- CN=87 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCADO 10,00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 12 Summary for Link 13L: Areas Combined (1-1 + 1-2) Inflow Area = 2.800 ac, 0.00% Impervious, Inflow Depth > 2.12" for 2-YR event Inflow = 9.91 cfs @ 11.98 hrs, Volume= 0.496 of Primary = 9.91 cfs @ 11.98 hrs, Volume= 0.496 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 1 1 m 3 0 LL Link 13L: Areas Combined (1-1 + 1-2) Hydrograph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hovers) 3 1Intlflw C3 Primary Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1124-hr 10-YR Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 13 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method Subcatchment4S: Pre Areal -1 (Qffsite) Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>3.49" Tc=7.0 min CN=83 Runoff=4.49 cfs 0.227 of Subcatchment12S: Pre Area 1-2 (0nsite) Runoff Area=2.020 ac 0.00% Impervious Runoff Depth>3.89" Tc=7.0 min CN=87 Runoff=12.67 cfs 0.655 of Link 13L: Areas Combi ned (1 -1 + 1-2) Inflow=17.16 cfs 0.882 of Primary=17,16 cfs 0.882 of Total Runoff Area = 2.800 ac Runoff Volume = 0.882 of Average Runoff Depth = 3.78" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1124-hr 10-YR Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 4S: Pre Area 1-1 (Offsite) Runoff = 4.49 cfs @ 11.98 hrs, Volume= 0.227 af, Depths 3.49" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-YR Rainfall=5.35" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, 5 4 3 N 3 0 LL 2 1 Subcatchment4S: Pre Area 1-1 (affsite) Hydrograph Type II 24-hr 10-YR Rainfall=5.35" Runoff Area=0.780 ac Runoff Volume=0.227 of Runoff Depth>3.49" Tc=7.0 min CN=83 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1124-hr 10-YR Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10,00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment 12S: Pre Area 1-2 (Dnsite) Runoff = 12.67 cfs @ 11.98 hrs, Volume= 0.655 af, Depths 3.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-YR Rainfall=5.35" Area (ac) CN Description 2.020 87 VRRM SPREADSHEET D.A. B 2.020 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment 12S: Pre Area 1-2 (Dnsite) Hydrograph 14 4 3 17 57 ,f, 12 Type II 24-hr 11 10-YR Rainfall=5.35" Runoff Area=2.020 ac Runoff Volume=0.655 of Runoff Depth>3.89" ° 7 LL 6 Tc=7.0 min 5 CN=87 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (PRE) Type 1124-hr 10-YR Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCADO IO.00-20 sin 08663 @ 2017 HydroCAD Software Solutions LLC Page 16 Summary for Link 13L: Areas Combined (1-1 + 1-2) Inflow Area = 2.800 ac, 0.00% Impervious, Inflow Depth > 3.78" for 10-YR event Inflow = 17.16 cfs @ 11.98 hrs, Volume= 0.882 of Primary = 17.16 cfs @ 11.98 hrs, Volume= 0.882 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 1 1 7 1 1 1 7 1 w 1 � 1 3 0 LL Link 13L: Areas Combined (1-1 + 1-2) Hydrograph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hovers) 3 1Intlflw a Primary yx���i1►E"il�)~���]�►1��i]��il;l7i]:ZiI�h►aI�Ll��l�J�:�r[i1►�� Post Area 1-3 {Offsite, ,� 7s detained) �9P Post Area 1-5 (C3nsite, SVIlM 3 1 8L Undetained) Post Area 1-4 (ansite, Detained) Areas Combined �Dubcat Reach On Link EHOydt-icnADO Diagram far Keswick Hall_Spa_Analysis Points 1 (POSTPrepared by Timmons Group, Printed 1/6/2020 10.00-20 sin 08663 © 2017 HydroCAD Software Solutions LLC Keswick Hall_Spa_Analysis Points 1 (POST) Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatch ment-nu mbers) 0.780 83 VRRM SPREADSHEET D.A. A (1S) 1.090 91 VRRM SPREADSHEET D.A. B (2S) 0.930 87 VRRM SPREADSHEET D.A. D (17S) 2.800 87 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (POST) Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAQ Software Solutions LLC Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.000 HSG A 0.000 HSG B 0.000 HSG C 0.000 HSG a 2.800 Other 1 S, 2S, 17S 2.800 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (POST) Prepared by Timmons Group HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Printed 1/6/2020 Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.000 0.000 0.000 0.000 0.780 0.780 VRRM SPREADSHEET D.A. A 1 S 0.000 0.000 0.000 0.000 1.090 1.090 VRRM SPREADSHEET D.A. B 2S 0.000 0.000 0.000 0.000 0.930 0.930 VRRM SPREADSHEET D.A. D 17 S 0.000 0.000 0.000 0.000 2.800 2.800 TOTAL AREA Keswick Hall_Spa_Analysis Points 1 (POST) Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAQ Software Solutions LLC Page 5 Pipe Listing (all nodes) Line# Node In -Invert Out -Invert Length Slope n QiamNVidth Height Inside -Fill Number (feet) (feet) (feet) (fuft) (inches) (inches) (inches) 1 19P 422.00 420.00 50.0 0.0400 0.013 18.0 0.0 0.0 Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 6 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Post Area 1-3 {Qffsite, Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>1.38" Tc=7.0 min CN=83 Runoff=1.83 cfs 0.090 of Subcatchment2S: Post Area 1-4 [Qnsite, Runoff Area=1.090 ac 0.00% Impervious Runoff Depth>1.99" Tc=6.0 min CN=91 Runoff=3.63 cfs 0.181 of Subcatchmentl7S: Post Area 1-5 [Qnsite, Runoff Area=0.930 ac 0.00% Impervious Runoff Depth>1.67" Tc=6.0 min CN=87 Runoff=2.65 cfs 0.129 of Pond 19P: SWM 3 Peak Elev=425.29' Storage=0.051 of Inflow=5.39 cfs 0.271 of Outflow=2.55 cfs 0.271 of Link 18L: Areas Combined Inflow=4.92 cfs 0.400 of Primary=4.92 cfs 0.400 of Total Runoff Area = 2.800 ac Runoff Volume = 0.400 of Average Runoff Depth = 1.71" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 7 Summary for Subcatchment 1 S: Post Area 1-3 (Offsite, detained) Runoff = 1.83 cfs @ 11.99 hrs, Volume= 0.090 af, Depths 1.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-Yr Rainfall=2.92" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, 2 Subcatchment 1S: Post Area 1-3 (Ofsite, detained) Hydrograph ❑ Runoff Type II 24-hr 1-Yr Rainfall=2.92" Runoff Area=0.780 ac IZT_TiT�ii M16 .. -I,-:�31Xrk1111M, i Runoff ❑epth>1.38" U. 1 Tc=7.0 min a 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Runoff = 3.63 cfs @ 11.97 hrs, Volume= 0.181 af, Depths 1.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-Yr Rainfall=2.92" Area (ac) CN Description 1.090 91 VRRM SPREADSHEET D.A. B 1.090 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) (cfs) 6.0 Direct Entry, 4 3 N 3 2 0 LL 1 Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Hydrograph Type II 24-hr 1-Yr Rainfall=2.92" Runoff Area=1.090 ac Runoff Volume=0.181 of Runoff Depth>1.99" Tc=G.0 min CN=91 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 17S: Post Area 1-5 (Qnsite, Undetained) Runoff = 2.65 cfs @ 11.97 hrs, Volume= 0.129 af, Depths 1.67" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 1-Yr Rainfall=2.92" Area (ac) CN Description 0.930 87 VRRM SPREADSHEET D.A. D 0.930 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 6.0 Direct Entry, 2 N 3 0 LL Subcatchment 17S: Post Area 1-5 (Onsite, Undetained) Hydrograph Type II 24-hr 1-Yr Rainfall=2.92" Runoff Area=0.930 ac Runoff Volume=0.129 of Runoff Depth>1.67" Tc=6.0 min CN=87 0 1 2 3 4 5 6 7 8 9 10 11 72 13 14 15 16 77 18 19 24 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 10 Summary for Pond 19P: SWM 3 Inflow Area = 1.870 ac, 0.00% Impervious, Inflow Depth > 1.74" for 1-Yr event Inflow = 5.39 cfs @ 11.97 hrs, Volume= 0.271 of Outflow = 2.55 cfs @ 12.08 hrs, Volume= 0.271 af, Atten= 53%, Lag= 6.4 min Primary = 2.55 cfs @ 12.08 hrs, Volume= 0.271 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 425.29' @ 12.08 hrs Surf.Area= 0.020 ac Storage= 0.051 of Plug -Flow detention time= 5.3 min calculated for 0.271 of (100% of inflow) Center -of -Mass det. time= 5.2 min ( 818.0 - 812.8 ) Volume Invert Avail.Storage Storage Description #1 422.00' 0.081 of 60.0" Round CMP_Round 60" L= 180.0' S= 0.0033 T Device Routing Invert Outlet Devices #1 Primary 422.00' 18.0" Round Culvert L= 50.0' CMP, projecting, no headwall, Ke= 0.900 Inlet/ Outlet Invert= 422.00'/ 420-00' S= 0.0400'1' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.77 sf #2 Device 1 422.00' 7.5" Vert. Orifice/Grate C= 0.600 #3 Primary 425.29' 30.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 426.70' 2.4' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary ❑utFlow Max=2.54 cfs @ 12.08 hrs HW=425.26' (Free Discharge) =Culvert (Passes 2.54 cfs of 10.65 cfs potential flow) 2=Orifice/Grate (Orifice Controls 2.54 cfs @ 8.27 fps) =Sharp -Crested Rectangular Weir( Controls 0.00 cfs) 3=Orifice/Grate ( Controls 0.00 cfs) Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAQ Software Solutions LLC Page 11 Pond 19P: SWM 3 H ydrograph p Inflow Cl Primary Time (hours) Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 7-Yr Rainfall=2.92" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 12 Summary for Link 18L: Areas Combined Inflow Area = 2.800 ac, 0.00% impervious, Inflow Depth > 1.71" for 1-Yr event Inflow = 4.92 cfs @ 11.99 hrs, Volume= 0.400 of Primary = 4.92 cfs @ 11.99 hrs, Volume= 0.400 af, Men= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs N 3 0 LL Link 18L: Areas Combined Hydrograph Time (hours) I� Intlflw C3 Primary Keswick Hall_Spa_Analysis Points 1 (POST) Type it 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 13 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method SubeatchmentlS: Post Area 1-3 {Qffsite, Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>1.89" Tc=7.0 min CN=83 Runoff=2.49 cfs 0.123 of Subeatchment2S: Post Area 1-4 [Qnsite, Runoff Area=1.090 ac 0.00% Impervious Runoff Depth>2.58" Tc=6.0 min CN=91 Runoff=4.62 cfs 0.234 of Subcatchmentl7S: Post Area 1-5 [Qnsite, Runoff Area=0.930 ac 0.00% Impervious Runoff Depth>2.22" Tc=6.0 min CN=87 Runoff=3.49 cfs 0.172 of Pond 19P: SWM 3 Peak Elev=425.79' Storage=0.061 of Inflow=7.03 cfs 0.357 of Dutflow=5.60 cfs 0.357 of Link 18L: Areas Combined Inflow=8.02 cfs 0.529 of Primary=8.02 cfs 0.529 of Total Runoff Area = 2.800 ac Runoff Volume = 0.529 of Average Runoff Depth = 2.27" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (POST) Type !l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 1 S: Post Area 1-3 (Offsite, detained) Runoff = 2.49 cfs @ 11.98 hrs, Volume= 0.123 af, Depths 1.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=3.54" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment 1S: Post Area 1-3 (Ofsite, detained) Hydrograph ❑ Runoff Type II 24-hr 2-YR Rainfall=3.54" s■ I■�:21TiT�MI1 -Z?Ti��iAvIs1 . i[�'iT:�311iL+Mi Runoff Depth>1.89" LL Tc=7.0 min 11 1 11/1 CN=83 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (POST) Type !l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 15 Summary for Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Runoff = 4.62 cfs @ 11.97 hrs, Volume= 0.234 af, Depths 2.58" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=3.54" Area (ac) CN Description 1.090 91 VRRM SPREADSHEET D.A. B 1.090 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) (cfs) 6.0 Direct Entry, 5 2 1 Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Hydrograph Type II 24-hr 2-YR Rainfall=3.54" Runoff Area=1.090 ac Runoff Volume=0.234 of Runoff Depth>2.58" Tc=6.0 min CN=91 0 1 2 S 4 6 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type !l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 16 Summary for Subcatchment 17S: Post Area 1-5 (Qnsite, Undetained) Runoff = 3.49 cfs @ 11.97 hrs, Volume= 0.172 af, Depths 2.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 2-YR Rainfall=3.54" Area (ac) CN Description 0.930 87 VRRM SPREADSHEET D.A. D 0.930 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) Ms) 6.0 Direct Entry, Subcatchment 17S: Post Area 1-5 (Onsite, Undetained) Hydrograph Type II 24-hr 3 2-YR Rainfall=3.54" Runoff Area=0.930 ac Runoff Volume=0.172 of 2 Runoff Depth>2.22" LL Tc=6.0 min CN=87 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type it 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 17 Summary for Pond 19P: SWM 3 Inflow Area = 1.870 ac, 0.00% Impervious, Inflow Depth > 2.29" for 2-YR event Inflow = 7.03 cfs @ 11.97 hrs, Volume= 0.357 of Outflow = 5.60 cfs @ 12.04 hrs, Volume= 0.357 af, Atten= 20%, Lag= 4.2 min Primary = 5.60 cfs @ 12.04 hrs, Volume= 0.357 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 425.79' @ 12.04 hrs Surf.Area= 0.019 ac Storage= 0.061 of Plug -Flow detention time= 5.3 min calculated for 0.357 of (100% of inflow) Center -of -Mass det. time= 5.2 min ( 810.5 - 805.4 ) Volume Invert Avail.Storage Storage Description #1 422.00' 0.081 of 60.0" Round CMP_Round 60" L= 180.0' S= 0.0033 T Device Routing Invert Outlet Devices #1 Primary 422.00' 18.0" Round Culvert L= 50.0' CMP, projecting, no headwall, Ke= 0.900 Inlet/ Outlet Invert= 422.00' l 420.00' S= 0.0400'/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.77 sf #2 Device 1 422.00' 7.5" Vert. Orifice/Grate C= 0.600 #3 Primary 425.29' 30.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 426.70' 2.4' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary ❑utFlow Max=5.41 cfs @ 12.04 hrs HW=425.77' (Free Discharge) =Culvert (Passes 2.75 cfs of 11.67 cfs potential flow) 2=Orifice/Grate (Orifice Controls 2.75 cfs @ 8.95 fps) =Sharp -Crested Rectangular Weir( Controls 0.00 cfs) 3=OrificelGrate (Orifice Controls 2.66 cfs @ 2.22 fps) Keswick Hall_Spa_Analysis Points 1 (POST) Type II 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAQ Software Solutions LLC Page 18 Pond 19P: SWM 3 H ydrograph p laflow Cl Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Keswick Hall_Spa_Analysis Points 1 (POST) Type 1l 24-hr 2-YR Rainfall=3.54" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 19 Summary for Link 18L: Areas Combined Inflow Area = 2.800 ac, 0.00% impervious, Inflow Depth > 2.27" for 2-YR event Inflow = &02 cfs @ 12.02 hrs, Volume= 0.529 of Primary = 8.02 cfs @ 12.02 hrs, Volume= 0.529 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs N 3 0 LL Link 98L: Areas Combined Hydrograph Time (hours) I� Intlflw C3 Primary Keswick Hall_Spa_Analysis Points 1 (POST) Type Il 24-hr 10-Yr Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 20 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Post Area 1-3 {Qffsite, Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>3.49" Tc=7.0 min CN=83 Runoff=4.49 cfs 0.227 of Subeatchment2S: Post Area 1-4 [Qnsite, Runoff Area=1.090 ac 0.00% Impervious Runoff Depth>4.32" Tc=6.0 min CN=91 Runoff-7.50 cfs 0.392 of Subcatchmentl7S: Post Area 1-5 [Qnsite, Runoff Area=0.930 ac 0.00% Impervious Runoff Depth>3.89" Tc=6.0 min CN=87 Runoff=5.96 cfs 0.302 of Pond 19P: SWM 3 Peak Eiev=426.96' Storage=0.079 of Inflow=11.87 cfs 0.619 of ❑utf9ow=11.36 cfs 0.619 of Link 18L: Areas Combined Inflow=17.01 cfs 0.921 of Primary=17.01 cfs 0.921 of Total Runoff Area = 2.800 ac Runoff Volume = 0.921 of Average Runoff Depth = 3.95" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 10-Yr Rainfal1=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment 1 S: Post Area 1-3 (Offsite, detained) Runoff = 4.49 cfs @ 11.98 hrs, Volume= 0.227 af, Depths 3.49" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr Rainfall=5.35" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, 5 4 3 N 3 0 LL 2 1 Subcatchment 1S: Post Area 1-3 (Ofsite, detained) Hydrograph Type II 24-hr 10-Yr Rainfall=5.35" Runoff Area=0.780 ac Runoff Volume=0.227 of Runoff Depth>3.49" Tc=7.0 min CN=83 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 10-Yr Rainfal1=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 22 Summary for Subcatchment 2S: Post Area 1-4 (Dnsite, Detained) Runoff = 7.50 cfs @ 11.96 hrs, Volume= 0.392 af, Depths 4.32" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr Rainfall=5.35" Area (ac) CN Description 1.090 91 VRRM SPREADSHEET D.A. B 1.090 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ftlft) (fUsec) (cfs) 6.0 Direct Entry, Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Hydrograph 8- 7.50 cfs Type II 24-hr 10-Yr Rainfall=5.35"" Runoff Area=1.090 ac 5 Runoff Volume=0.392 of Runoff Cepth>4.32" 4LL Tc=6.0 min 3 CN=91 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 10-Yr Rainfal1=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 17S: Post Area 1-5 (Qnsite, Undetained) Runoff = 5.96 cfs @ 11.97 hrs, Volume= 0.302 af, Depths 3.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 10-Yr Rainfall=5.35" Area (ac) CN Description 0.930 87 VRRM SPREADSHEET D.A. D 0.930 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 6.0 Direct Entry, Subcatchment 17S: Post Area 1-5 (Onsite, Undetained) Hydrograph Type II 24-hr 10-Yr Rainfall=5.35" Runoff Area=0.930 ac 4- Runoff Volume=0.302 of Runoff Depth>3.89" ° i-L 3- Tc=f.O min CN=87 2 1 0 1 2 S 4 6 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type Il 24-hr 10-Yr Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 24 Summary for Pond 19P: SWM 3 Inflow Area = 1.870 ac, 0.00% Impervious, Inflow Depth > 3.97" for 10-Yr event Inflow = 11.87 cfs @ 11.97 hrs, Volume= 0.619 of Outflow = 11.36 cfs @ 12.00 hrs, Volume= 0.619 af, Atten= 4%, Lag= 1.9 min Primary = 11.36 cfs @ 12.00 hrs, Volume= 0.619 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 426.96' @ 12.00 hrs Surf.Area= 0.010 ac Storage= 0.079 of Plug -Flow detention time= 4.8 min calculated for 0.619 of (100% of inflow) Center -of -Mass det. time= 4.7 min ( 795.3 - 790.6 ) Volume Invert Avail.Storage Storage Description #1 422.00' 0.081 of 60.0" Round CMP Round 60" L= 180.0' S= 0.0033 T Device Routing Invert Outlet Devices #1 Primary 422.00' 18.0" Round Culvert L= 50.0' CMP, projecting, no headwall, Ke= 0.900 Inlet/ Outlet Invert= 422.00' l 420.00' S= 0.0400'/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.77 sf #2 Device 1 422.00' 7.5" Vert. Orifice/Grate C= 0.600 #3 Primary 425.29' 30.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 426.70' 2.4' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary ❑utFlow Max=11.22 cfs @ 12.00 hrs HW=426.94' (Free Discharge) =Culvert (Passes 4.11 cfs of 13.75 cfs potential flow) 2=Orifice/Grate (Orifice Controls 3.18 cfs @ 10.36 fps) =Sharp -Crested Rectangular Weir(Weir Controls 0.93 cfs @ 1.61 fps) 3=OrificelGrate (Orifice Controls 7.11 cfs @ 5.69 fps) Keswick Hall_Spa_Analysis Points 1 (POST) Type 1l 24-hr 90-Yr Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAQ Software Solutions LLC Page 25 1 1 1 1 Pond 19P: SWM 3 H ydrograph 0 1 2 3 4 5 6 7 6 9 13 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Inflow © Primary Keswick Hall_Spa_Analysis Points 1 (POST) Type Il 24-hr 90-Yr Rainfall=5.35" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 26 Summary for Link 18L: Areas Combined Inflow Area = 2.800 ac, 0.00% impervious, Inflow Depth > 3.95" for 10-Yr event Inflow = 17.01 cfs @ 11.99 hrs, Volume= 0.921 of Primary = 17.01 cfs @ 11.99 hrs, Volume= 0.921 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs �II �r �5 t3 12 h 1 z0 3 9 D LL 7 n 5 4 3 2 1 0 0 Link 18L: Areas Combined Hydrograph 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hovers) E3 Intlflw [] Primary Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 27 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind}Trans method - Pond routing by Stor-Ind method SubcatchmentlS: Post Area 1-3 {Qffsite, Runoff Area=0.780 ac 0.00% Impervious Runoff Depth>6.74" Tc=7.0 min CN=83 Runoff=8.35 cfs 0.438 of Subeatchment2S: Post Area 1-4 [Qnsite, Runoff Area=1.090 ac 0.00% Impervious Runoff Depth>7.71" Tc=6.0 min CN=91 Runoff=12.90 cfs 0.700 of Subcatchmentl7S: Post Area 1-5 [Qnsite, Runoff Area=0.930 ac 0.00% Impervious Runoff Depth>7.22" Tc=6.0 min CN=87 Runoff=10.63 cfs 0.560 of Pond 19P: SWM 3 Peak Eiev=427.81' Storage=0.081 of Inflow=21.05 cfs 1.138 of ❑utflow=21.60 cfs 1.138 of Link 18L: Areas Combined Inflow=32.23 cfs 1.698 of Primary=32.23 cfs 1.698 of Total Runoff Area = 2.800 ac Runoff Volume = 1.698 of Average Runoff Depth = 7.28" 100.00% Pervious = 2.800 ac 0.00% Impervious = 0.000 ac Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCADO 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 28 Summary for Subcatchment 1 S: Post Area 1-3 (Offsite, detained) Runoff = 8.35 cfs @ 11.98 hrs, Volume= 0.438 af, Depths 6.74" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type II 24-hr 100-Yr Rainfall=8.80" Area (ac) CN Description 0.780 83 VRRM SPREADSHEET D.A. A 0.780 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 7.0 Direct Entry, Subcatchment 1S: Post Area 1-3 (Ofsite, detained) Hydrograph 9 8 35 cfs Type 11 24-hr 100-Yr Rainfall=8.80" 7- Runoff Area=0.780 ac 6 Runoff Volume=0.438 of Runoff Cepth>6.74" LL 4 Tc=7.0 min CN=83 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCADO 10.00-20 s/n 08663 © 2017 HydroCAD Software Solutions LLC Page 29 Summary for Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Runoff = 12.90 cfs @ 11.96 hrs, Volume= 0.700 af, Depths 7.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs> dt= 0.05 hrs Type II 24-hr 100-Yr Rainfall=8.80" Area (ac) CN Description 1.090 91 VRRM SPREADSHEET D.A. B 1.090 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) (ofs) 6.0 Direct Entry, Subcatchment 2S: Post Area 1-4 (Onsite, Detained) Hydrograph 14 12.90 cfs 13 Type II 24-hr 121 11- 100-Yr Rainfall=8.80" 10- Runoff Area=1.090 ac Runoff Volume=0.700 of 8 Runoff Depth>7.71 " 0 7. U. 6 Tc=6.0 min 5 CN=91 4 3 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type 1124-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 ©2017 HydroCAD Software Solutions LLC Page 30 Summary for Subcatchment 17S: Post Area 1-5 (Qnsite, Undetained) Runoff = 10.63 cfs @ 11.96 hrs, Volume= 0.560 af, Depths 7.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-24.00 hrs> dt= 0.05 hrs Type II 24-hr 100-Yr Rainfall=8.80" Area (ac) CN Description 0.930 87 VRRM SPREADSHEET D.A. D 0.930 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (fUsec) Ms) 6.0 Direct Entry, 11 10 9 8 7 N Li 3 6 0 U. 5 4 3 2 1 0 Subcatchment 17S: Post Area 1-5 (Onsite, Undetained) Hydrograph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ❑ Runoff Keswick Hall_Spa_Analysis Points 1 (POST) Type/1 24-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCAD@ 10.00-20 s/n 08663 0 2017 HydroCAD Software Solutions LLC Page 31 Summary for Pond 19P: SWM 3 [93] Warning: Storage range exceeded by 0.21' [88] Warning: Qout>Qin may require smaller dt or Finer Routing Inflow Area = 1.870 ac, 0.00% Impervious, Inflow Depth > 7.30" for 100-Yr event Inflow = 21.05 cfs @ 11.97 hrs, Volume= 1.138 of Outflow = 21.60 cfs @ 11.96 hrs, Volume= 1.138 af, Atten= 0%, Lag= 0.0 min Primary = 21.60 cfs @ 11.96 hrs, Volume= 1.138 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 427.81' @ 11.96 hrs Surf.Area= 0.000 ac Storage= 0.081 of Plug -Flow detention time= 4.3 min calculated for 1.138 of (100% of inflow) Center -of -Mass det. time= 4.2 min ( 779.0 - 774.8 ) Volume Invert Avail.Storage Storage Description #1 422.00' 0.081 of 60.0" Round CMP_Round 60" L= 180.0' S= 0.0033 T Device Routing Invert Outlet Devices #1 Primary 422.00' 18.0" Round Culvert L= 50.0' CMP, projecting, no headwall, Ke= 0.900 Inlet/ Outlet Invert= 422.00' 1420.00' S= 0.0400'/' Cc= 0.900 n= 0.013 Concrete pipe, bends & connections, Flow Area= 1.77 sf #2 Device 1 422.00' 7.5" Vert. Orifice/Grate C= 0.600 #3 Primary 425.29' 30.0" W x 6.0" H Vert. Orifice/Grate C= 0.600 #4 Device 1 426.70' 2.4' long Sharp -Crested Rectangular Weir 0 End Contraction(s) Primary GutFlow Max=20.86 cfs @ 11.96 hrs HW=427.75' (Free ❑ischarge) t:=Culvert (Passes 11.92 cfs of 15.02 cfs potential flow) 2=Orifice/Grate (Orifice Controls 3.45 cfs @ 11.23 fps) =Sharp -Crested Rectangular Weir(Weir Controls 8.47 cfs @ 3.35 fps) 3=GrificelGrate (Orifice Controls 8.95 cfs @ 7.16 fps) Keswick Hall_Spa_Analysis Points 1 (POST) Type it 24-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAQ Software Solutions LLC Page 32 24 23 22 21 20 19 18 17 16 1s m 14 is 13 12 0 11 1❑ 9 8 7 6 1 Pond 19P: SWM 3 H ydrograph i I —— 1 —1—— -4 — — a- —1 — I — I — 4 —1 — — —- 1 1. = — I —1— — - —1 ——L-1——-L-1—=� —1— I I I � I I I I— -1 — — r —1 — .— - — 1 — — - — 1 — — —1 — — —1— — —1 Inflow Area=1.870 ac - Peak Elegy=427.81' - Storage=0.081 of I I I I— — I — r - — 1— .. II— — —I— 4- — 1— .. L 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Inflow © Primary Keswick Hall_Spa_Analysis Points 1 (POST) Type it 24-hr 100-Yr Rainfall=8.80" Prepared by Timmons Group Printed 1/6/2020 HydroCAD0 10.00-20 s/n 08663 @ 2017 HydroCAD Software Solutions LLC Page 33 Summary for Link 18L: Areas Combined Inflow Area = 2.800 ac, 0.00% impervious, Inflow Depth > 7.28" for 100-Yr event Inflow = 32.23 cfs @ 11.96 hrs, Volume= 1.698 of Primary = 32.23 cfs @ 11.96 hrs, Volume= 1.698 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs 36 34 32 30 28 26 24 22 20 3 18 LL 16 14' 12 10 8 6 4 2 0 0 Link 18L: Areas Combined Hydrograph 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hovers) 3 1Intlflw C3 Primary SECTION 5 NUTRIENT CREDIT AVAILIBILITY LETTER