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WPO200500005 Calculations Stormwater Management Plan 2005-01-07
• STORMWATER MANAGEMENT NARRATIVE GREENBRIER . STATION ALBEMARLE COUNTY, VIRGINIA 27 October 2005 Rev. 3/6/06 Prepared by: TERRA PARTNERS 200 6th Street,NE Charlottesville,Virginia 22902 (434)295-6496 zoA 3, N oUo Lit. No. 35 I A r / 326 • V v V4-5:5is ltALLTy STORMWATER MANAGEMENT NARRATIVE GREENBRIER STATION ALBEMARLE COUNTY,VIRGINIA 27 October 2005 Rev. 3/6/06 Prepared by: TERRA PARTNERS 200 6th Street,NE Charlottesville,Virginia 22902 (434)295-6496 titenT,i,virni s CP A e o an . raR4tin Lic. No.35326 .M rp .r O `1570PTALECG GR EEN]BRI ER STATION 10/27/05 Stormwater Management Narrative Rev. 3/6/06 Project Description This project proposes the development of the undeveloped lot between Flower's Bakery and Design Environs into a small industrial/office/retail park. The property is approximately 2.4 acres of wooded, rolling terrain. It is surrounded on all sides with existing development. The southern boundary of the property fronts on Greenbrier Drive. Immediately to the east is Flower's Bakery, to the west is Design Environs, and to the north is a small parcel separating the subject site from Westfield Road. A small, manmade drainage channel running from west to east and an existing gas easement separate the northern 20% of the property from the remainder.This channel conveys storm runoff from the adjacent developed properties to the west and Commonwealth Drive toward Route 29. This site plan proposes to divert the channel in a storm pipe and to fill in a portion of the channel. An Army Corps of Engineering permit to perform this activity has been secured.The remainder of the development is proposed to occur to the south of the existing channel. Stormwater Management The portion of the property to the south of the channel consists of two existing small watershed (drainage)areas. Drainage Area A drains to the southeast corner(Greenbrier Drive/Flower's Bakery) of the property to a concrete swale, VDOT standard drainage structure,and into the existing storm system adjacent to Greenbrier Drive. Drainage Area B drains to the existing channel to the north. Using the Rational Method with Atlas 14 Rainfall Precipitation Frequency Data: Pre-Development A: D.A.= 1.58 acres C=0.30 Tc= 10.57 minutes Q2= 1.91 cfs Qio=2.49 cfs Pre-Development B: D.A.=0.79 acres C=0.30 Tc=9.52 minutes Q2= 1.00 cfs Qui= 1.30cfs Stormwater management for the project is proposed to be handled by Filterra units for water quality and large underground pipe systems for detention.Two underground detention pipe systems are proposed, one for each drainage area. U SWM A consists of two 192 If rows of 48 'HDPE with a reinforced concrete box outlet structure.The outlet box has a 48"tall reinforced concrete baffle wall with a 6"x 6" orifice at the bottom and spillway at the top.The orifice restricts the outflow from the detention pipes to the pre-development release rates for the 2-year and 10-year storm for Drainage Area A while the spillway at the top allows larger storms to safely pass through the system. GREEN t 1!IER STATION 10/27/05 Stormwater Management Narrative Rev. 3/6/06 SWM B consists of one 82.5 If row of 48"HDPE with a reinforced concrete box outlet structure.The outlet box has a 48"tall reinforced concrete baffle wall with a 4.5"x 4.5"orifice at the bottom and spillway at the top.The orifice restricts the outflow from the detention pipes to the pre-development release rates for the 2-year and 10-year storm for Drainage Area B while the spillway at the top allows larger storms to safely pass through the system. The drainage areas were modeled in the post-development condition using the,Rational Method with Atlas 14 Rainfall Precipitation Frequency Data and HydroCad 7.1 software. Post-Development A: D.A.= 1.67 acres C=0.79 Tc=6.20 minutes Q2=1.95 cfs(based on critical duration analysis) Quo=2.34 cfs(based on critical duration analysis) Post-Development B: D.A.=0:70 acres C=0.65 Tc=5.00 minutes Q2= 1.06 cfs (based on critical duration analysis) Qio= 1.29 cfs(based on critical duration analysis) • AQ 2S SWM A POST-A 4ubC Reach A I Drainage Diagram for GREENBRIER Prepared by Alan Franklin;Terra Concepts 3/9/2006 HydroCAD®7.10 sin 002893 ®2005 HydroCAD Software Solutions LLC GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=6 min, .Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 2 HydroCAD®7.10 sin 002893 ©2005 HydroCAD Software.Solutions LLC 3/9/2006 Time span=0.00-2.00 hrs, dt=0.01 hrs, 201 points Runoff by Rational method, Rise/Fall=1.0/2.0 xTc Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 2S: POST-A Runoff Area=1.670 ac Runoff Depth=0.56" Tc=6.2 min C=0.79 Runoff=6.35 cfs 3,421 cf Pond 4P: SWM A Peak Elev=480.02' Storage=2,099 cf Inflow=6.35 cfs 3,421 cf Outflow=1.75 cfs 3,422 cf Total Runoff Area =72,745 sf Runoff Volume=3,421 cf Average Runoff Depth = 0.56" GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 3 HydroCAD®7.10 sin 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Subcatchment 2S: POST-A Runoff = 6.35 cfs @ 0.10 hrs, Volume= 3,421 cf, Depth= 0.56" Runoff by Rational method, Rise/Fall=1.0/2.0 xTc, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs VA-Albemarle-ATLASI4 2-Year Duration=6 min, Inten=4.92 in/hr Area (ac) C Description 1.670 0.79 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.2 Direct Entry, Subcatchment 2S: POST-A Hydrograph 71' I O Runoff I B.35cfe©0,1Ohre I Runoff=6.35 cfs @ 0.10 hrs s- VA-Albemarle-ATLASI4 2-Year . Duration=6-mini 5 Inten=4.92 in/hr • Runoff A rea=1.670..a c... 4 Runoff Volume=3,421 cf . . _ Runoff.Depth=0.56" 3 r Tc=6.2 min 2 -er ®q o /%%%/ %%/////// //:%/// %%%%% //./%%% 0 + 2 Time (hours) GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 4 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Subcatchment 2S: POST-A Time Runoff Time Runoff Time Runoff Time Runoff (hours) (cfs) (hours) (cfs) (hours) (cfs) (hours) (cfs) 0.00 0.00 0.52 0.00 1.04 0.00 1.56 0.00 0.01 0.63 0.53 0.00 1.05 0.00 1.57 0.00 0.02 1.27 0.54 0.00 1.06 0.00 1.58 0.00 0.03 1.90 0.55 0.00 1.07 0.00 1.59 0.00 0.04 2.53 0.56 0.00 1.08 0.00 1.60 0.00 0.05 3.17 0.57 0.00 1.09' 0.00 1.61 0.00 0.06 3.80 0.58 0.00 1.10 0.00 1.62 0.00 0.07 4.43 0.59 0.00 1.11 0.00 1.63 0.00 0.08 5.07 0:60 0.00 1.12 0.00 1.64 0.00 0.09 5.70 0.61 0.00 1.13 0.00 1.65 0.00 0.10 6.33 0.62 0.00 1.14 0.00 1.66 0.00 0.11 6.02 0.63 0.00 1.15 0.00 1.67 0.00 0.12 5.70 0.64 0.00 1.16 0.00 1.68 0.00 0.13 5.38 0.65 0.00 1.17 0.00 1.69 0.00 0.14 5.07 0.66 0.00 1.18 0.00 1.70 0.00 0.15 4.75 0.67 0.00 1.19 0.00 1.71 0.00 0.16 4.43 0.68 0.00 1.20 0.00 1.72 0.00 0.17 4.12 0.69 • 0.00 1.21 0.00 1.73 0.00 0.18 3.80 0.70 0.00 1.22 0.00 1.74 0.00 0.19 3.48 0.71 0.00 '1.23 0.00 1.75 0.00 0.20 3.17 . 0.72 0.00 1.24 0.00 1.76 0:00 0.21 2.85 0.73 0.00 1.25 0.00 1.77 0.00 0.22 2.53 0.74 0.00 1.26 0.00 1.78 0.00 0.23 2.22 0.75 0.00 1.27 0.00 1.79 0.00 0.24 1.90 0.76 .0.00 1.28 0.00 1.80 0.00 0.25 1.58 0.77 0.00 1.29 0.00 1.81 0.00 0.26 1.27 0.78 0.00 1.30 0.00 1.82 0.00 0.27 0.95 0.79 0.00 1.31 0.00 1.83 0.00 0.28 0.63 0.80 0.00 1.32 0.00 1.84 0.00 0.29 0.32 0.81 0.00 1.33 0.00 1.85 0.00 0.30 0.00 0.82 0.00 1.34 0.00 1.86 .0.00 0.31 0.00 0.83 0.00 .1.35 0.00 1.87 0.00 0.32 0.00 0.84 0.00 1.36 0.00 1.88 0.00 0.33 0.00 0.85 0.00 1.37 0.00 1.89 0.00 0.34 0.00 0.86 0.00 1.38 0.00 1.90 0.00 0.35 0.00 0.87 0.00 1.39 • 0.00 1.91 0.00 ' 0.36 0.00 0.88 0.00 1.40 0.00 1.92 0.00 0.37 0.00 0.89 0.00 1.41 0.00 1.93 0.00 0.38 0.00 0.90 0.00 1.42 0.00 1.94 0.00 0.39 0.00 0.91 0.00 1.43 0.00 1.95 0.00 0.40 0.00 0.92 0.00 1.44 0.00 1.96 0.00 0.41 0.00 0.93 .0.00 1.45 0.00 1.97 0.00 0.42 0.00 0.94 0.00 1.46 0.00 1.98 0.00 0.43 0.00 0.95 0.00 1.47 0.00 1.99 0.00 0.44 0.00 0.96 0.00 1.48 0.00 2.00 0.00 0.45 0.00 0.97 0.00 1.49 0.00 0.46 0.00 0.98 0.00 1.50 0.00 0.47 0.00 0.99 0.00 1.51 0.00 0.48 0.00 1.00 0.00 1.52 0.00 0.49 0.00 1.01 0.00 1.53 0.00 0.50 0.00 1.02 0.00 1.54 0.00 0.51 0.00 1.03 0.00 1.55 0.00 • GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 5 HydroCAD®7.10 sin 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006, Pond 4P: SWM A Inflow Area = 72,745 sf, Inflow Depth = 0.56" for 2-Year event Inflow = 6.35 cfs @ 0.10 hrs, Volume= 3,421 cf Outflow = 1.75 cfs @ 0.24 hrs, Volume= 3,422 cf, Atten= 72%, Lag= 8.6 min Primary = 1.75 cfs @ 0.24 hrs, Volume= 3,422 cf Routing by Stor-Ind method, Time Span= 0.00-2.00 hrs„dt= 0.01 hrs Peak Elev= 480.02' @ 0.24 hrs Surf.Area= 1,513 sf Storage= 2,099 cf Plug-Flow detention time= 12.9 min calculated for 3,405 cf (100% of inflow) Center-of-Mass det. time= 12.9 min (20.9-8.0 ) Volume Invert Avail.Storage Storage Description #1 477.75' 4,825 cf 48.0"D x 192.00'L Horizontal Cylinder S= 0.0050 '/' x 2 Device Routing Invert Outlet Devices #1 Primary 477.65' 15.0" x 10.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert=477.55' S= 0.0100 'I' Cc= 0.900 n= 0.013 #2 Device 1 477.65' 0.50'W x 0.50' H Vert. Orifice/Grate C= 0.600 #3 Device 1 481.65' 3.0' long x 4.0' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 0.50' Rise #4 Device 1 482.15' 4.7' long x 4.5' high Sharp-Crested Rectangular Weir X 0.00 '2 End Contraction(s) 2.50' Rise Primary OutFlow Max=1.75 cfs @ 0.24 hrs HW=480.02' (Free Discharge) t-1=Culvert (Passes 1.75 cfs of 7.81 cfs potential flow) �2=Orifice/Grate (Orifice Controls 1.75 cfs @ 7.0 fps) 3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 6 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 4P: SWM A Hydrograph • D Inflow ` 7- I e.as Csm 0.10 hrs I ©Primary 1 .... ._' •: , . ......Inflow-Area=7-2;745 sf' s- d?,. • Inflow=6.35 cfs @ 0.10 hrs ;0,1 • Primary=1.75 cfs @ 0.24 hrs 5= ciA Peak EIev=480.02' Storage=2,099 cf u' 3 • 7.1 t IA 3is ' 1.75 cf,sit 0.24 hrs 1- /fib 0 1 2 Time (hours) Pond 4P: SWM A Stage-Discharge • [O Primary .. .. 483-. A��������/, rr� PDrOsted[ta(anglil`ei4Ver; , 482 / ;Sharp Drastflist9ectengulag, e . . .. -. : . .. ., _. . ... _. ., . .. ..... .. m 481 ' 0 480 if 479 478 ' , ''uldart t ;-0dfice/Grate' ' .111 ./ • 0 1 2 3 4 9 ,g', 2. 3 9. '10. . .17 '12 .13' '14 , Discharge (cfs) GREENBRIER VA-Albemarle-ATLA'S14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 7 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC . 3/9/2006 Pond 4P: SWM A Stage-Area-Storage / 0 Storage 484-• 0/ • . . .. .. • 29 Asak - . . :. �j._. .... 479 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 Storage(cubic-feet) E 0 00 G 0) w t. arn (Y) E m NIA 0 a • O Q co N J )n CO s a tit lo CO CCCO C -J a) 0 a Z•m OMrro 0 W W V rN W OM W W ONMNI- W WW W V MNrO1,- W V NO W W WW ON- WM IOM ON-- r � ..- O N V W W mOrr N M V V W CO W CO W W f� N- Nh W W (O (O (O (gif V 'R W COCO V V V MMMMM NU A O ES000000 ' E to O 0- 0 0 Q I 00 em C= .'-.. Cn V ON W W V (00 � rO] 01Or V r W CO W ONNN O W (() f- M000rhM0 L0 f� MO W N W V ON- MO Q 0 O 0 O 0) rOONM V W h W OrNM V COCO0I0) 0) 000OOOQ) O) m W W rrr W W (0LO W V V V MMNNNrrO Q 0 T '6 > ' � � � � r � n � NN N N N NNNNN NN000 W 000000NNNNNNNNNNNNnn NNNNNNNNNN - OmI 2 w vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv ` 0 N 0 0) ^0N- W u) N0 V MO) N NO) 'V' W W V OtO N- W W W MO V W N- W rN- O) r V Nor COr N� Vr0 W W W OrM N 0)0) NCD O) W 0) Nr VrN U) NNr CON W M W W 0) 0) W (DN W NCOO V W Nr MO V 0) M W M W N NNNM W O E W rrNMM W W OrM V N W r W 0) 0) 000000000) 0) W W I,- W W IOCn V V MNNrr000) 0) W W r CM 00 r .-r rr r<NNNNN[VNNrrrc-rrr rrrr a- - r 1209 CO O 0 Li" a (p to ?� N 0M N- O CO N- 0 CO1� O CON O W N- ) M N O W N- CO M N O W N- COM N 0000000000000000000000 E Q O O C D W N O C O r W V O 1- M O N M O I V r W V r W u D N O) C O N 0) W C'M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 W r CV(� OrrN M M V W 6c6 W uilsi6 V V (6607 N N NrrrOcidci J00 (JOOcici CJC70Ci C700 (700000 u- ar m10 Z 2Q W m0 Q) `OrNM V COW - W OOrNM 'V' (O (ON W OOrNM V (O W N- W OOrNM V IOCON- W OOrNM V CO W N- W O) Or 0 0 0 O 0 0 0 0 O 0 E N N N N N N N N N N M M M M M M M M M M V V V V V V V V V V 0 N d T F g 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C] O CJ 0 0 CJ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 067 GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 9 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 4P: SWM A (continued) Time Inflow Storage Elevation Primary (hours) (pfs) (cubic-feet) (feet) (cfs) 0.52 0.00 736 479.05 1.29 0.53 0.00 690 479.01 1.27 0.54 0.00 645 478.98 1.25 0.55 0.00 601 478.94 1.22 0.56 0.00 557 478.90 1.20 0.57 0.00 514 478.86 1.18 0.58 0.00 472 478.82 1.15 0.59 0.00 432 478.78 1.12 0.60 0.00 392 478.74 1.10 0.61 0.00 353 478.70 1.07 0.62 0.00 315 478.65 1.04 0.63 0.00 278 478.61 1.01 0.64 0.00 242 478.56 0.97 0.65 0.00 208 478.51 0.94 ' 0.66 0.00 175 478.46 0.89 0.67 0.00 144 478.41 0.85 0.68 0.00 114 478.35 0.79 0.69 0.00 87 478.28 0.73 0.70 0.00 62. 478.21 0.65 0.71 0.00 40 478.14 0.55 0.72 0.00 23 478.06 0.42 0.73 0.00 10 477.97 0.29 0.74 0.00 2 477.86 0.15 0.75 0.00 0 477.75 0.00 0.76 0.00 0 477.75 0.00 0.77 0.00 0 477.75 0.00 0.78 0.00 0 477.75 0.00 0.79 0.00 0 477.75 0.00 0.80 0.00 0 477.75 ' 0.00 0.81 0.00 0 477.75 0.00 0.82 0.00 0 477.75 0.00 0.83 0.00 0 477.75 0.00 0.84 0.00 0 477.75 0.00 0.85 0.00 0 477.75 0.00 0.86 0.00 0 477.75 0.00 0.87 0.00 0 477.75 0.00 0.88 0.00 0 477.75 0.00 0.89 0.00 0 477.75 0.00 0.90 0.00 0 477.75 0.00 0.91 0.00 0 477.75 0.00 0.92 0.00 0 477.75 0.00 0.93 0.00 0 477.75 0.00 0.94 0.00 0 477.75 0.00 0.95 0.00 0 477.75 0.00 0.96 0.00 • 0 477.75 0.00 0.97 0.00 0 477.75 0.00 0.98 0.00 0 477.75 0.00 0.99 0.00 0 477.75 0.00 1.00 0.00 0 477.75 0.00 1.01 0.00 0 477.75 0.00 1.02 0.00 0 477.75 0.00 1.03 0.00 0 477.75 0.00 GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 10 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for.Pond 4P: SWM A (continued) Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 1.04 0.00 0 477.75 0.00 1.05 0.00 0 477.75 0.00 1.06 0.00 0 477.75 0.00 1.07 0.00 0 477.75 0.00 1.08 0.00 0 477.75 0.00 1.09 0.00 0 477.75 0.00 1.10 0.00 0 477.75 0.00 1.11 0.00 0 477.75 0.00 1.12 0.00 0 477.75 0.00 1.13 0.00 0 477.75 0.00 1.14 0.00 0 477.75 0.00 ' 1.15 0.00 0 477.75 0.00 1.16 0.00 0 477.75 0.00 1.17 0.00 0 477.75 0.00 1.18 0.00 0 477.75 0.00 1.19 0.00 0 477.75 0.00 1.20 0.00 0 477.75 0.00 1.21 0.00 0 477.75 0.00 1.22 0.00 0 477.75 0.00 1.23 0.00 0 477.75 0.00 1.24 0.00 0 477.75 0.00 1.25 0.00 0 477.75 0.00 1.26 0.00 0 477.75 0.00 1.27 0.00 0 477.75 0.00 1.28 0.00 0 477.75 0.00 1.29 0.00 0 477.75 0.00 1.30 0.00 0 477.75 0.00 1.31 0.00 0 477.75 0.00 1.32 0.00 0 477.75 0.00 1.33 0.00 0 477.75 0.00 1.34 0.00 0 477.75 0.00 1.35 0.00 0 477.75 0.00 1.36 0.00 0 477.75 0.00 1.37 0.00 0 477.75 0.00 1.38 0.00 0 477.75 0.00 1.39 0.00 0 477.75 0.00 1.40 0.00 0 477.75 0.00 1.41 0.00 0 477.75 0.00 1.42 0.00 0 477.75 0.00 1.43 0.00 0 477.75 0.00 1.44 0.00 0 477.75 0.00 1.45 0.00 0 477.75 0.00 1.46 0.00 0 477.75 0.00 1.47 0.00 0 477.75 0.00 1.48 0.00 0 477.75 0.00 1.49 0.00 0 477.75 0.00 1.50 0.00 0 477.75 0.00 1.51 0.00 0 477.75 0.00 1.52 0.00 0 477.75 0.00 1.53 0.00 0 477.75 0.00 1.54 0.00 0 477.75 0.00 1.55 0.00 0 477.75 0.00 GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=6 min, Inten=4.92 in/hr Prepared by Alan Franklin; Terra Concepts Page 11 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 4P: SWM A (continued) Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 1.56 0.00 0 477.75 0.00 1.57 0.00 0 477.75 0.00 1.58 0.00 0 477.75 0.00 1.59 0.00 0 477.75 0.00 1.60 • 0.00 0 477.75 0.00 1.61 0.00 0 477.75 0.00 1.62 0.00 0 477.75 0.00 1.63 0.00 0 477.75 0.00 1.64 0.00 0 477.75 0.00 1.65 0.00 0 477.75 0.00 1.66 0.00 0 477.75 0.00 1.67 0.00 0 477.75 0.00 1.68 0.00 0 477.75 0.00 1.69 0.00 0 477.75 0.00 1.70 0.00 0 477.75 0.00 1.71 0.00 0 477.75 0.00 1.72 0.00 0 477.75 0.00 1.73 0.00 0 477.75 0.00 - 1.74 0.00 0 477.75 0.00 1.75 0.00 0 477.75 0.00 1.76 0.00 0 477.75 0.00 1.77 0.00 0 477.75 0.00 1.78 0.00 0 477.75 0.00 1.79 0.00 0 477.75 0.00 1.80 0.00 0 477.75 0.00 1.81 0.00 0 477.75 0.00 1.82 0.00 0 477.75 0.00 1.83 0.00 0 477.75 0.00 1.84 0.00 0 477.75 0.00 1.85 0.00 0 477.75 0.00 1.86 0.00 0 477.75 0.00 1.87 0.00 0 477.75 0.00 1.88 0.00 0 477.75 0.00 1.89 0.00 0 477.75 0.00 1.90 0.00 0 477.75 0.00 1.91 0.00 0 477.75 0.00 1.92 0.00 0 477.75 0.00 1.93 0.00 0 477.75 0.00 1.94 0.00 0 477.75 0.00 1.95 0.00 0 477.75 0.00 1.96 0.00 0 477.75 0.00 1.97 0.00 0 477.75 0.00 1.98 0.00 0 477.75 0.00 1.99 0.00 0 477.75 0.00 2.00 0.00 0 477.75 0.00 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 12 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Time span=0.00-2.00 hrs, dt=0.01 hrs, 201 points Runoff by Rational method, Rise/Fall=1.0/2.0 xTc Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 2S: POST-A Runoff Area=1.670 ac Runoff Depth=0.73" Tc=6.2 min C=0.79 Runoff=8.17 cfs 4,403 of Pond 4P: SWM A Peak Elev=480.56' Storage=2,918 cf Inflow=8.17 cfs 4,403 cf Outflow=1.96 cfs 4,404 cf Total Runoff Area =72,745 sf Runoff Volume=4,403 cf Average Runoff Depth= 0.73" GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 13 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Subcatchment 2S: POST-A Runoff = 8.17 cfs @ 0.10 hrs, Volume= 4,403 cf, Depth= 0.73" Runoff by Rational method, Rise/Fall=1.0/2.0 xTc, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs VA-Albemarle-ATLAS14 10-Year Duration=6 min, Inten=6.33 in/hr Area (ac) C Description 1.670 0.79 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.2 Direct Entry, Subcatchment 2S: POST-A Hydrograph g-' D Runoff 8.17 cfs w 010 hrs 1 _ ,_._.. ...... ... ..... .._..- g Runoff=8.17 cfs @ 0.10 hrs �1 :... . VA-Albemarle-ATLAS1.410-Year.. 7 • "� Duration=6 min, Inten=6.33 inlhr 6 Runoff Area=1.670 ac Runoff Volume=4,403 cf 3 e s7 Runoff Depth=0.73" LT. 4 t.9 „ Tc=6.2 min r nz -C=0.79 t 3 1,7 2 1. OA 0 1 2 Time (hours) mm0 O O o 0 0 0 O O O o 0 o 0 0 0 0 0 0 0 0 O 0 o o o o o o o o o 0 o o 0 o o o o o o o 0 o o o o o o 0 o o g '� a ry , ! 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A A is W W W W W W W W W IJ IV IV IJ N N N N N N O O O O O O y 3 C O o in W (D 01 A W N > o w m V m O A W N --x O (O m V m O 1 A W N >O cO m V m Ol A G1 N > O (O m V OPm A W N --' O (O m V m (n A— (D 6 n a 00000000000000000000000000000000o00000oo000000000000-• S S E -& 0000000000000000.000000000000000-000000000000000000000y0 m = �a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 OO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0�. 3 O V ri- CD O f0) F • 'C N O z - m l O (O (O (00) (007 (O (6mmm6cO m DOm m V V JJ JJJJ V V caO mmm mm mm01 (nO1(n a 3 0 0 0 O (O m V m (n AwN >O W m J m M A W N > O W m V O (nA. W N >O W m V.O (n AW N > O W m J O m 1 C W Ct X O 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (j j 3 O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O o O) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 O 0 0 0 O 0 . O c'w m II O) W m co —(a W o m 5. 0 a • GREENBRIER VA-Albemarle-ATLAS14 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 15 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software.Solutions LLC 3/9/2006 Pond 4P: SWM A Inflow Area = 72,745 sf, Inflow Depth = 0.73" for 10-Year event Inflow = 8.17 cfs @ 0.10 hrs, Volume= 4,403 cf Outflow = 1.96 cfs @ 0.25 hrs, Volume= 4,404 cf, Atten= 76%, Lag= 9.0 min Primary = 1.96 cfs @ 0.25 hrs, Volume= 4,404 cf Routing by Stor-lnd method, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs Peak Elev=480.56' @ 0.25 hrs Surf.Area= 1,499 sf Storage= 2,918 cf Plug-Flow detention time= 15.9 min calculated for 4,382 cf(100% of inflow) Center-of-Mass det. time= 16.0 min ( 24.0- 8.0 ) Volume Invert Avail.Storage Storage Description #1 477.75' 4,825 cf 48.0"D x 192.00'L Horizontal Cylinder S= 0.0050'/' x 2 Device Routing Invert Outlet Devices #1 Primary 477.65' 15.0" x 10.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 477.55' S= 0.0100 '/' Cc= 0.900 n= 0.013 #2 Device 1 477.65' 0.50'W x 0.50' H Vert. Orifice/Grate C= 0.600 • #3 Device 1 481.65' 3.0' long x 4.0' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 0.50' Rise #4 Device 1 482.15' 4.7' long x 4.5' high Sharp-Crested Rectangular Weir X 0.00 2 End Contraction(s) 2.50' Rise Primary OutFlow Max=1.96 cfs @ 0.25 hrs HW=480.56' (Free Discharge) t_,Culvert (Passes 1.96 cfs of 8.94 cfs potential flow) -2=Orifice/Grate (Orifice Controls 1.96 cfs @ 7.9 fps) -3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) -4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 16 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 4P: SWM A Hydrograph Inflow ` 5- I017cis@om hurl _ 0 Primary1 Inflow Area=72,745 sf 8 Inflow=8.17 cfs @ 0 10 hrs 7 " Primary=1.96 cfs @ 0.25 hrs t v . , w Peak EIev=480.56' 6 • w w Storage=2,918 cf $ 5 au 5 "idt�f E 4— ,ti '4,u4 • r 3- tif .. 1 56 ch v e35 hrs o i 2 Time (hours) Pond 4P: SWM A Stage-Discharge 0 Primary 484- 1.7 483 �� rearriharp-C ednotaraira-FglWent _. r 482 SherP-GCest rtaq 611-8406/g trt 'q 481 480 ' 479 . 478 culvert+Orifice/Grate • 9. . 1 2 3 .4. 5 .6. : : .7 8 . 9 .10. ,11, .12 13 14 Discharge (cis) GREENBRIER VA-Albemarle-ATLASI4 10=Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 17 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 4P: SWM A Stage-Area-Storage / .:_... 0 Storage 484- 0 . 483- a 482-` /V w ::: ��®®���s• � -tit 479 478 M Flo nzontal QyIi 1de / 0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 Storage(cubic-feet) 9 _ O0 0000000000000000000000000000000000000000.00o00000000ogi o- m ."0 > -' > > j -s -s O O O O O O O O O O y B O 0 I T > OCOmJmmA W N > O (Oo - mmA W N >0 COmJmtA W N >Ow m V mmAoN > Oo 0Jmm4, W N O.�W o rn Dm O D_ W G 00000000000000000000o000 »NN Nw W AA ACnmp o m -4 v0 -Jo A W N > o0 i -fin >0623 D m O O O O O O O O O O O O O O O O O O O O O O A m N m O A m 1 V m O A m W -I -s C n (0 W J W 0 1 J 0) O N A m W O. -., 0 000Oo0 0000000000000000 > NN W a01mmJmm (00 > NN W a01N AN > (Om m010) NO.� `Z iii > > >> > >> > >> N N N N N N N N N N N N N N N N N N N N N N N N IJ N N > >>> > ' A ACnmm V Jm (D CD00 > N N W AAmmm V mm m (D 10 (DmmJ V m mAN >(D V (n W W�(n W N p) W cOAomNmAO wmwm > mA > JA m m m (D» om Am > W W > m W mmmJ A W mmmm W > W CO N n) AO V 01 W N >NNAm c0 N 0Om >m01 W > 0NO W W JJNNJ V NO A > N V m m W > W > m01 > (+) (0 0000� 0 m = 01 M s A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A.A A A A A A A A A A A A A A A A W = n J V J J V J V J 1 V J m 0 m m m m m m m m m m m m m 0) m m m m m m m m m m V J J V V J V V J V J J V J V— < O. 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Q O 0. o_ W t W 0) O r E n no m D • 0 m rn m� w o � rn CO .1 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 19 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 4P: SWM A (continued) Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.52 0.00 1,378 479.53 1.54 0.53 0.00 1,323 479.50 1.52 0.54 0.00 1,269 479.46 1.50 0.55 0.00 1,215 479.42 1.48 0.56 0.00 1,162 479.38 1.46 0.57 0.00 1,110 479.34 1.44 0.58 0.00 1,058 479.30 1.42 0.59 0.00 1,007 479.27 1.40 0.60 0.00 957 479.23 1.38 0.61 0.00 907 479.19 1.36 0.62 0.00 859 479.15 1.34 . 0.63 0.00 811 479.11 1.32 0.64 0.00 763 479.07 1.30 0.65 0.00 717 479.04 1.28 0.66 0.00 671 479.00 1.26 0.67 0.00 626 478.96 1.24 0.68 0.00 582 478.92 1.21 0.69 0.00 539 478.88 1.19 0.70 0.00 497 478.84 1.16 0.71 0.00 455 478.80 1.14 0.72 0.00 415 478.76 1.11 0.73 0.00 375 478.72 1.09 0.74 0.00 337 478.68 1.06 0.75 0.00 299 478.63 1.03 0.76 0.00 263 478.59 0.99 0.77 0.00 228 478.54 0.96 0.78 0.00 194 478.49 0.92 0.79 0.00 162 478.44 0.88 0.80 0.00 131 478.38 0.83 0.81 0.00 102 478.32 0.77 0.82 0.00 76 478.26 0.70 0.83 0.00 52 478.18 0.61 0.84 0.00 32 478.11 0.50 0.85 0.00 17 478.02 0.37 0.86 0.00 6 477.93 0.23 0.87 0.00 0 477.79 0.07 0.88 0.00 0 477.75 0.00 0.89 0.00 0 477.75 0.00 0.90 0.00 0 477.75 0.00 0.91 0.00 0 477.75 0.00 0.92 0.00 0 477.75 0.00 0.93 0.00 0 477.75 0.00 0.94 0.00 0 477.75 0.00 1 0.95 0.00 0 477.75 0.00 0.96 0.00 0 477.75 0.00 0.97 0.00 0 477.75 0.00 0.98 0.00 0 477.75 0.00 0.99 0.00 0 477.75 0.00 1.00 0.00 0 477.75 0.00 1.01 0.00 0 477.75 0.00 1.02 0.00 0 477.75 0.00 1.03 0.00 0 477.75 0.00 00'0 9L'LLb 0 00'0 99'4 00'0 SL'LLb 0 00'0 179'4 00'0 9L'LL4 0 00'0 E9'4 00'0 9L'La? 0 00'0 Z9'4 00'0 9L'LLb 0 00'0 49'4 00'0 9L'LLb 0 00'0 09'4 00'0 SCate 0 00'0 64'4 00'0 9L'LL4 0 00'0 917'4 00'0 9L'LL4 0 00'0 Lb'4 00'0 9L'GL4 0 00'0 94'4 00'0 9L'LL4 0 00'0 94'4 00'0 9L'LL4 0 00'0 b4'4 00'0 9L'LL4 0 00'0 ell I, 00'0 S1.114 0 00'0 Z4'4 00'0 9L'LL4 0 00'0 4b'4 Oat SLIM? 0 00'0 04'4 00'0 SL'Lb' 0 00'0 6£'4 00'0 SL'LLD' 0 00'0 9£'4 00'0 9L'LL4 0 00'0 LE'4 00'0 SL'LL4 0 00'0 9E'4 00'0 9L'LLb 0 00'0 S£'4 00'0 SL'LLb 0 00'0 4E'4 00'0 9L'LLb 0 00'0 En 00'0 9L'Lib 0 00'0 ZE'4 00'0 9L'GLb 0 00'0 4E'4 00'0 SL'at' 0 00'0 OE'4 00'0 9L'LLb 0 00'0 6Z'4 00'0 9L'LL4 0 00'0 9Z'4 00'0 9L'LLb 0 00'0 LZ'4 00'0 9L'LL4 0 00'0 9Z'4 00'0 SL'LL4 0 00'0 9Z'4 00'0 EL'UV 0 00'0 IZ'4 00'0 9G'LL4 0 00'0 EZ'4 00'0 9L'LLb 0 00'0 ZZ'4 00'0 9VLL4 0 00'0 4Z'l 00'0 9L'LL4 0 00'0 0Z'4 00'0 SL'LL4 0 00'0 64'4 00'0 9L'114 0 00'0 94'4 • 00'0 SL'LL4 0 00'0 L4'4 00'0 EL'UV 0 00'0 94'4 00'0 EL'LL4 0 00'0 94'4 00'0 9L'LL4 0 00'0 174'4 00'0 9L'LL4 0 00'0 £4'4 00'0 9L'LLb 0 00'0 Z4'4 00'0 9L'LL4 0 00'0 44'4 00'0 9L'LL4 0 00'0 01'4 00'0 9L'LL4 0 00'0 60'4 00'0 9L'all 0 00'0 90'4 00'0 9L'LLb 0 00'0 L0'4 00'0 9L'Lib 0 00'0 90'4 00'0 9L'LLb 0 00'0 90'4 00'0 9L'114 0 00'0 40'4 (slo) pal) (4aa;-oigno) (slo) (sino4) AJewud uogene9 a6eJo;g Mogul ewlj (panui;uoo) v WMS :dti Puod ao; gdea6oapAH 900Z/6/£ 011 suogniog eieM;;og QVUaPAH 900Z© E69Z00 u/s 041®CVQaPAH 0Z e6ed s;daouo3 eiial :uujueid uely Aq paiedaid Amur gg'9=ua;u! 'up 9=uoge na Je0A-OL 176SVTLV-apewacw-yA 2931a8N33210 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=6 min, Inten=6.33 in/hr Prepared by Alan Franklin; Terra Concepts Page 21 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 • Hydrograph for Pond 4P: SWM A (continued) Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 1.56 0.00 0 477.75 0.00 1.57 0.00 0 477.75 0.00 1.58 0.00 , 0 477.75 0.00 1.59 0.00 0 477.75 0.00 1.60 0.00 0 477.75 0.00 1.61 0.00 0 477.75 0.00 1.62 0.00 0 477.75 0.00 1.63 0.00 0 477.75 0.00 1.64 0.00 0 477.75 0.00 1.65 0.00 0 477.75 0.00 1.66 0.00 0 477.75 0.00 1.67 0.00 0 477.75 0.00 1.68 0.00 0 477.75 0.00 1.69 0.00 0 477.75 0.00 1.70 0.00 0 477.75 0.00 1.71 0.00 0 477.75 0.00 1.72 0.00 0 477.75 0.00 1.73 0.00 0 477.75 0.00 1.74 0.00 0 477.75 0.00 1.75 0.00 0 477.75 0.00 1.76 0.00 0 477.75 0.00 1.77 0.00 0 477.75 0.00 1.78 0.00 0 477.75 0.00 1.79 0.00 0 477.75 0.00 1.80 0.00 0 477.75 0.00 1.81 0.00 0 477.75 0.00 1.82 0.00 0 477.75 0.00 1.83 0.00 0 477.75 0.00 1.84 0.00 0 477.75 0.00 1.85 0.00 0 477.75 0.00 1.86 ' 0.00 0 477.75 0.00 1.87 0.00 0. 477.75 0.00 1.88 0.00 0 477.75 0.00 1.89 0.00 0 477.75 0.00 1.90 0.00 0 477.75 0.00 1.91 0.00 0 477.75 0.00 1.92 0.00 0 477.75 0.00 1.93 0.00 0 477.75 0.00 1.94 0.00 0 477.75 0.00 1.95 0.00 0 477.75 0.00 1.96 0.00 _ 0 477.75 0.00 1.97 0.00 0 477.75 0.00 1.98 0.00 0 477.75 0.00 1.99 0.00 0 477.75 0.00 2.00 0.00 0 477.75 0.00 • GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=21 min, Inten=2.90 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 • Pond 4P: SWM A Critical Duration Analysis / ®Elevation I - Ei 8- /� in*y v O Primary 5- .. V _.. - ..-. d . .. ... ...- .._ . .-480 d � � U 4 . .4 y D LL NtM1 a ...... n •: i V' aiP,. I • &� k M1 •3- s 1E, ms • .,4 ''uo- �:G AFT ';,7 " 0 5 10 15 20 25 30 35 40 45 50 55 60 85 70 75 BD 85 90 95 100 105 110 115 120 Event Duration (minutes) GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=21 min, Inten=2.90 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 sin 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Critical Duration Analysis for Pond 4P: SWM A Duration Elevation Inflow Primary (minutes) (feet) (cfs) (cfs) 5 479.62 5.42 1.58 10 480.33 5.48 1.87 15 480.47 4.58 1.93 20 480.52 3.96 1.95 25 480.51 3.49 1.94 30 480.46 3.13 1.92 35 480.39 2.85 1.90 40 480.30 2.62 1.86 45 480.21 2.42 1.83 50 480.11 2.26 1.79 55 480.00 2.11 1.74 60 479.90 1.99 1.70 65 479.80 1.88 1.66 70 479.70 1.78 1.61 75 479.60 1.70 1.57 80 479.50 1.62 1.52 85 479.41 1.55 1.48 90 479.32 1.49 1.43 95 479.24 1.43 1.39 100 479.16 1.38 1.35 105 479.09 1.33 1.31 110 479.02 1.28 1.27 115 478.95 1.24 1.23 120 478.89 1.20 1.20 GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=21 min, Inten=2.90 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 4P: SWM A Hydrograph ... . .. ... .. ..... . .. -. . _ _. . .. .... .......... ®Inflow 4- � WtfSu: _ OPrimaly� Inflow Area=72,745 sf ' Inflow=3.85 cfs @ 0.11 hrs Primary=1:95 cfs @ 0.45 hrs 3 ' CZ Peak Elev=480.52' to Storage=2,850 cf s* 2- ' I,m/ 0 45 in/ vet A. } ' la te--te-- /i, z/f,/,S.,,.. -o/ iOe z,ee%z :22'•k /dd ;,, %/p_o i 2 Time (hours) GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=21 min, /nten=2.90 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.1.0 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 4P: SWM A Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.00 0.00 0 477.75 0.00 0.05 1.86 94 478.30 0.75 0.10 3.73 427 478.77 1.12 0.15 3.85 893 479.18 1.36 0.20 3.85 1,327 479.50 1.52 0.25 3.85 1,734 479.78 1.65 0.30 3.85 2,121 480.04 1.76 0.35 3.85 2,489 480.28 1.86 0.40 2.92 2,757 480.46 1.92 • 0.45 1.99 2,850 480.52 1.95 . 0.50 1.06 2,775 480.47 1.93 0.55 0.12, 2,539 480.31 1.87 0.60 0.00 2,212 480.10 1.78 0.65 0.00 1,899 479.89 1.70 0.70 0.00 1,601 479.69 1.61 0.75 0.00 1,320 479.49 1.52 0.80 0.00 1,055 479.30 1.42 i 0.85 0.00 808 479.11 1.32 0.90 0.00 580 478.92 1.21 0.95 0.00 373 478.72 1.08 1.00 0.00 192 478.49 0.92 1.05 0.00 51 478.18 0.61 1.10 0.00 0 477.75 0.00 1.15 0.00 0 477.75 0.00 1.20 0.00 0 477.75 0.00 1.25 0.00 0 477.75 0.00 1.30 0.00 0 477.75 0.00 1.35 0.00 0 477.75 0.00 1.40 0.00 0 477.75 0.00 1.45 0.00 0 477.75 0.00 1.50 0.00 0 477.75 0.00 1.55 0.00 0 477.75 • 0.00 1.60 0.00 0 477.75 0.00 1.65 0.00 0 477.75 0.00 1.70 0.00 0 477.75 0.00 1.75 0.00 0 477.75 0.00 1.80 0.00 0 477.75 0.00 1.85 0.00 0 477.75 0.00 • 1.90 0.00 0 477.75 0.00 1.95 0.00 0 477.75 0.00 2.00 0.00 0 477.75 0.00 GRE E BmE A-w_r AIUg41GAwDur m«am, Um=mi r Prepared by AlnFranklin, ter Concepts - 3/9/2006 ��q«�0Gaa oz5wd�m SoftwareSolutions LLC Pond 4P: SWM A Hydragraph �� I /_ . « . . . 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I 7 • • l ! ; VIAA K.c d {{ :". .. ... U V¢ ✓fit ?`* av _ 6i Y a. hi 3 "far M1Avyt wf� ar 2 S- ' n 0 5 10 15 20 25 30 35 40 45 60 55 00 65 70 75 80 65 90 95 100. 105 110 115 120 Event Duration)minutes) GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=29 min, Inten=3.26 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Critical Duration Analysis for Pond 4P: SWM A Duration Elevation Inflow Primary (minutes) (feet) (cfs) (cfs) 5 480.02 6.95 1.75 10 481.04 7.13 2.13 15 481.36 6.04 2.24 20 481.54 5.27 2.30 25 481.63 4.70 2.32 30 481.65 4.26 2.34 35 481.62 3.91 2.32 40 481.55 3.62 2.30 45 481.47 3.37 2.27 50 481.37 3.16 2.24 55 481.26 2.98 2.21 60 481.15 2.82 2.17 65 481.04 2.68 2.13 70 480.93 2.56 2.09 75 480.82 2.45 2.06 80 480.71 2.35 2.02 85 480.60 2.26 1.98 90 480.50 2.17 1.94 95 480.40 2.10 1.90 100 480.30 2.03 1.86 105 480.21 1.96 1.83 110 480.12 1.90 1.79 115 480.03 1.84 1.75 120 479.94 1.79 1.72 • � 5P POST-B SWM B (Subca) Reach '• • Drainage Diagram for GREENBRIER Prepared by Alan Franklin;Terra Concepts 3/9/2006 HydroCAD®7.10 s/n 002893 02005 HydroCAD Software Solutions LLC GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page 2 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC • 3/9/2006 Time span=0.00-2.00 hrs, dt=0.01 hrs, 201 points Runoff by Rational method, Rise/Fall=1.0/2.0 xTc Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment IS: POST-B Runoff Area=0.700 ac Runoff Depth=0.42" Tc=5.0 min C=0.65 Runoff=2.32 cfs 1,068 cf Pond 5P: SWM B Peak Elev=486.26' Storage=505 cf Inflow=2.32 cfs 1,068 cf Outflow=0.98 cfs 1,068 cf Total Runoff Area = 30,492 sf Runoff Volume= 1,068 cf Average Runoff Depth =0.42" i GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page 3 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Subcatchment 1 S: POST-B Runoff = 2.32 cfs @ 0.09 hrs, Volume= 1,068 cf, Depth= 0.42" Runoff by Rational method, Rise/Fall=1.0/2.0 xTc, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs VA-Albemarle-ATLAS14 2-Year Duration=5 min, Inten=5.18 in/hr Area (ac) C Description 0.700 0.65 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 1S: POST-B /j Hydrograph 11 0 Runoff l 2.ffi de 9 0.08 hre I Runoff=2.32 cfs @ 0.09 hrs VA-Albemarle-ATLAS14-2-Year 2- ,er^ Duration=5 min, Ord Inten=5.18 in/hr '� Runoff Area=0.700 ac Runoff Volume=1,068 cf 3 a Runoff Depth=0.42" LT li Tc=5:0 min.:. ' III C=0.65 nC ,a J U 1 2 Time (hours) GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=5 min, Inten=5.16 in/hr Prepared by Alan Franklin; Terra Concepts Page 4 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC - 3/9/2006 Hydrograph for Subcatchment 1 S: POST-B Time Runoff Time Runoff Time Runoff Time Runoff (hours) (cfs) (hours) (cfs) (hours) (cfs) (hours) (cfs) 0.00 0.00 0.52 0.00 1.04 0.00 1.56 0.00 0.01 0.29 0.53 0.00 1.05 0.00 1.57 0.00 0.02 0.57 0.54 0.00 1.06 0.00 1.58 0.00 0.03 0.86 0.55 0.00 1.07 0.00 1.59 0.00 0.04 1.14 0.56 0.00 1.08 0.00 1.60 0.00 0.05 1.43 0.57 0.00 1.09 0.00 1.61 0.00 0.06 1.71 0.58 0.00 1.10 0.00 1.62 0.00 0.07 2.00 0.59 0.00 1.11 0.00 1.63 0.00 0.08 2.28 0.60 0.00 1.12 0.00 1.64 0.00 0.09 2.28 0.61 0.00 1.13 0.00 1.65 0.00 • 0.10 2.14 ' 0.62 0.00 1.14 0.00 1.66 0.00 0.11 2.00 0.63 0.00 1.15 0.00 1.67 0.00 0.12 - 1.85 0.64 0.00 1.16 0.00 1.68 0.00 0.13 1.71 0.65 0.00 1.17 0.00 1.69 0.00 0.14 1.57 0.66 0.00 1.18 0.00 1.70 0.00 0.15 1.43 0.67 0.00 1.19 0.00 1.71 0.00 0.16 1.28 0.68 - 0.00 1.20 0.00 1.72 0.00 0.17 1.14 0.69 0.00 1.21 0.00 1.73 0.00 0.18 1.00 0.70 0.00 1.22 0.00 1.74 0.00 0.19 0.86 0.71 0.00 1.23 0.00 1.75 0.00 0.20 0.71 0.72 0.00 1.24 0.00 1.76 0.00 0.21 0.57 0.73 0.00 1.25 0.00 1.77 0.00 0.22 0.43 0.74 0.00 1.26 0.00 1.78 0.00 0.23 0.29 0.75 0.00 1.27 0.00 1.79 0.00 0.24 0.14 0.76 0.00 1.28 0.00 1.80 0.00 0.25 0.00 0.77 0.00 1.29 0.00 1.81 0.00 0.26 0.00 0.78 0.00 1.30 0.00 1.82 0.00 0.27 0.00 0.79 0.00 1.31 0.00 1.83 0.00 0.28 0.00 0.80 0.00 1.32 0.00 1.84 0.00 0.29 0.00 0.81 0.00 1.33 0.00 1.85 0.00 0.30 0.00 0.82 0.00 1.34 0.00 1.86 0.00 0.31 0.00 0.83 0.00 1.35 0.00 1.87 0.00 0.32 0.00 0.84 0.00 1.36 0.00 1.88 0.00 0.33 0.00 0.85 0.00 1.37 0.00 1.89 0:00 0.34 0.00 0.86 0.00 1.38 0.00 1.90 0.00 0.35 0.00 0.87 0.00 1.39 0.00 1.91 0.00 ,0.36 0.00 0.88 0.00 1.40 0.00 1.92 0.00 0.37 0.00 0.89 0.00 1.41 0.00 1.93 0.00 0.38 0.00 0.90 0.00 1.42 0.00 1.94 0.00 0.39 0.00 0.91 0.00 1.43 0.00 1.95 0.00 0.40 0.00 0.92 0.00 1.44 0.00 1.96 0.00 0.41 0.00 0.93 0.00 1.45 0.00 1.97 0.00 0.42 0.00 0.94 0.00 1.46 0.00 1.98 0.00 0.43 0.00 0.95 0.00 1.47 0.00 1.99 0.00 0.44 0.00 0.96 0.00 1.48 0.00 2.00 0.00 0.45 0.00 0.97 0.00 1.49 0.00 0.46 0.00 0.98 0.00 1.50 0.00 0.47 0.00 0.99 0.00 1.51 0.00 0.48 0.00 1.00 0.00 1.52 0.00 0.49 0.00 1.01 0.00 1.53 0.00 0.50 0.00 1.02 0.00 1.54 0.00 0.51 0.00 1.03 0.00 1.55 0.00 GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page 5 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC. 3/9/2006 Pond 5P: SWM B Inflow Area = 30,492 sf, Inflow Depth = 0.42" for 2-Year event Inflow = 2.32 cfs @ 0.09 hrs, Volume= 1,068 cf Outflow = 0.98 cfs @ 0.18 hrs, Volume= 1,068 cf, Atten= 58%, Lag= 5.8 min Primary = 0.98 cfs @ 0.18 hrs, Volume= 1,068 cf Routing by Stor-Ind method, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs Peak Elev=486.26' @ 0.18 hrs Surf.Area= 329 sf Storage= 505 cf Plug-Flow detention time= 6.1 min calculated for 1,062 cf(100% of inflow) Center-of-Mass det. time= 6.1 min ( 12.8 - 6.7) Volume Invert Avail.Storage Storage Description #1 484.09' 1,037 cf 48.0"D x 82.50'L Horizontal Cylinder S=0.0050 'I' Device Routing Invert Outlet Devices #1 Primary 484.09' 15.0" x 13.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert=483.00' S= 0.0838 '/' Cc= 0.900 n= 0.013 #2 Device 1 484.09' 0.38' W x 0.38' H Vert. Orifice/Grate C= 0.600 #3 Device 1 488.09' 2.0' long x 4.0' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 0.50' Rise #4 Primary 488.59' •5.7' long x 4.5' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.50' Rise Primary OutFlow Max=0.98 cfs @ 0.18 hrs HW=486.25' (Free Discharge) Culvert (Passes 0.98 cfs of 7.33 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.98 cfs @ 6.8 fps) • LL3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) -4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page 6 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Hydrograph / D Inflow 0 Primary 2.32 c(s iC,0.09 hrs Inflow Area=30,492 sf ® -Inflow=2.32 cfs @ 0.09'hrs •�,� Primary=0:98 cfs @ 0.18 hrs t�,i Peak Elev=486.26' IN Storage=505 cf iii t 10.98cfs e!0.18 hrs i 1- :47; dFfre� 0 o 1 2 Time (hours) Pond 5P: SWM B Stage-Discharge e gar. algae o Primary 489 :.:.-® . i/� Sharp.Ciestad72ec1afiguletWali , ;; _..pSI era Cfested;RectangularWeiti - . -. .. .. . .. . .. - 488 487- 0 w • 486- % 485- *,Culvert+Onfiae......; .- 5 1'0 16 . 20 . 25 . . 3e 25 40 Discharge (cis) GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page 7 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Stage-Area-Storage 490- 0 0 Storage 489- 488- di 2 487- _,. . .. .. . . . Ifte u. j�A/S. ... .. .. ...... .. ... Vitt 485- /�/1 0 100 200 300 400 500 600 700 800 900 1,000 Storage(cubic feet) GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=5 min, Inten=5.18 in/hr Prepared by Alan Franklin; Terra Concepts Page S HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC ' 3/9/2006 Hydrograph for Pond 5P: SWM B Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.00 0.00 0 484.09 0.00 0.01 0.29 3 484.28 0.10 0.02 0.57 13 484.42 0.23 0.03 0.86 ' 28 484.54 0.34 0.04 1.14 50 484.67 0.43 0.05 1.43 80 484.81 0.50 0.06 1.71 117 484.97 0.58 0.07 2.00 161 485.14 0.65 0.08 2.28 214 485.33 0.71 0.09 2.28 269 485.52 0.77 0.10 2.14 320 485.68 0.82 0.11 2.00 364 485.82 0.86 0.12 1.85 402 485.94 0.90 0.13 1.71 433 486.04 0.92 0.14 1.57 459 486.12 0.94 0.15 1.43 479 486.18 0.96 0.16 1.28 493 486.22 0.97 0.17 1.14 501 486.24 0.97 0.18 1.00 505 486.25 0.98 0.19 0.86 503 486.25 0.98 0.20 0.71 496 486.23 0.97 . 0.21 0.57 485 486.19 0.96 0.22 0.43 468 486.14 0.95 0.23 0.29 447 486.08 0.93 0.24 0.14 422 486.00 0.91 0.25 0.00 392 485.91 0.89 0.26 0.00 360 485.81 0.86 0.27 0.00 330 485.72 0.83 0.28 0.00 300 485.62 0.80 i 0.29 0.00 272 485.53 0.78 0.30 0.00 245 485.44 0.75 0.31 0.00 218 485.35 0.72 0.32 0.00 193 485.26 ' 0.69 0.33 ' 0.00 169 485.17 0.66 0.34 0.00 146 485.09 0.62 0.35 0.00 124 485.00 0.59 0.36 0.00 103 484.92 0.55 0.37 0.00 84 484.83 0.51 0.38 0.00 66 484.75 0.47 0.39 0.00 50 484.67 0.43 0.40 0.00 36 484.59 0.38 0.41 0.00 23 484.50 0.32 0.42 0.00 13 484.42 0.23 0.43 0.00 6 484.34 0.15 0.44 0.00 2 484.25 0.08 0.45 0.00 0 484.17 0.03 0.46 0.00 0 484.09 0.00 0.47 0.00 0 484.09 0.00 0.48 0.00 0 484.09 0.00 0.49 0.00 0 484.09 0.00 0.50 0.00 0 484.09 0.00 0.51 0.00 0 484.09 0.00 � m0 0 Z mN 1:13a.rn Lri co II c 03 c E 10 u o d W 0 c c L O co C' -J My W di y <t o cr o CO Q Cl) Q 2m Lo (a0000000000000000000000000000000000000000000000000000 N '0 E �0000000000000000000000000000000000000000000000000000 C `m Op 0 n- E 20 a Q) Q.Q -Q WO 0 C M O M M M O M O M M O M M m M M O M M M M M M m M M M rn M O M M O O M m O M M M O M M O M M O M MTD O m Q () 0 4- 000000000000000000000000000000000000000000000000000000 Q C . 0 >--moo ni mawomawowmawoawoawommmmco 4 Ti wwoawoawoawoawomowoawommmmmmmmmawowawowwmmmmma�oa`toolcooa`roawomm . 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IP Ce CO -0, F O 0a = 00'0 601784 0 00'0 00'Z 00'0 601784 0 00'0 66'4 00'0 601784 0 00'0 96'4 00'0 601784 0 00'0 L6'l 00'0 60184 0 00'0 96'4 00'0 601784 0 00'0 96'4 ' 00'0 601784 0 00'0 46'4 00'0 601784 0 00'0 E6'4 00'0 60'484 0 00'0 Z6'4 00'0 601784 0 00'0 46'4 00'0 601794 0 00'0 06'4 00'0 601784 0 00'0 68'4 00'0 601784 0 00'0 881. 00'0 601784 0 00'0 L9'4 00'0 601784 0 00'0 99'4 00'0 60'484 0 00'0 98'4 00'0 60'484 0 00'0 49'4 00'0 60'494 0 00'0 £8'4 00'0 601784 0 00'0 38'4 00'0 601784 0 00'0 48'4 00'0 601784 0 00'0 08'1. 00'0 60'484 0 00'0 62.'4 00'0 601784 0 00'0 82.'4 00'0 601784 0 00'0 2.2.1. 00'0 60'494 0 00'0 911- 00'0 60'484 0 00'0 9L'4 00'0 601784 0 00'0 4L'4 00'0 601794 0 00'0 EL'4 00'0 601784 0 00'0 32.'4 00'0 60'484 0 00'0 4L'4 00'0 60'484 0 00'0 01'4 00'0 60'484 0 00'0 69'4 00'0 60'484 0 00'0 99'4 00'0 601784 0 00'0 19'4 00'0 60'494 0 00'0 99'4 00'0 60'484 0 00'0 99'4 ' 00'0 601784 0 00'0 49'4 . 00'0 60'494 0 00'0 £9'4 00'0 601784 0 00'0 39'4 00'0 601784 0 00'0 49'4 00'0 601784 0 00'0 09'4 00'0 601794 0 00'0 69'4 00'0 60'484 0 00'0 89'4 00'0 60'484 0 00'0 L9'4 00'0 60'484 0 00'0 99'4 (s;o) (;ea;) ()aa;-oigno) (s;a) (smog) Meuaud uoi;ena13 a6ejo;g Mogul awil (panul;uoo) 8 WMS :dg puod Jo; ydeJ6oJpAH 900Z/6/£ 311 suup os amMgoS OV00JPAH 900Z O E68Z00 u/s O41®OVOOJPAH 4l abed s;deouoo eual :u!piueid uely Aq paaedaid ay/u! 96•g=ua)u/ `upv g=uoi;eJna aeaA-Z 171•Sb'7lt/-alaeillaglb'-b'/1 N31218N33210 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, Inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 12 HydroCADO 7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Time span=0.00-2.00 hrs, dt=0.01 hrs, 201 points Runoff by Rational method, Rise/Fall=1.0/2.0 xTc Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment IS: POST-B Runoff Area=0.700 ac Runoff Depth=0.54" Tc=5.0 min C=0.65 Runoff=2.97 cfs 1,370 cf Pond 5P: SWM B Peak Elev=486.91' Storage=716 cf Inflow=2.97 cfs 1,370 cf Outflow=1.13 cfs 1,371 cf Total Runoff Area = 30,492 sf Runoff Volume = 1,370 cf Average Runoff Depth = 0.54" GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, Inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 13 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Subcatchment IS: POST-B Runoff = 2.97 cfs @ 0.09 hrs, Volume= 1,370 cf, Depth= 0.54" Runoff by Rational method, Rise/Fall=1.0/2.0 xTc, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs VA-Albemarle-ATLASI4 10-Year Duration=5 min, Inten=6.65 in/hr Area (ac) C Description 0.700 0.65 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment IS: POST-B Hydrograph Runoff 12.97 cfs 000f"I-,.-. - . . .., . ..:. .._. _. .._ .. ._. .. . ... .... - ,. . Runoff=2.97 cfs @ 0.09 hrs VA-Albemarle-ATLASI4 10-Year Duration=5 min, i Inten=6.65 in/hr 2-' Fr j Runoff Area=0.700 ac:1 0 Runoff Volume=1,370 cf 1 ) Runoff Depth=0.54" LL ` Tc=5.0 min P"r C=0.65 '- f wu ire: 0 1 2 Time (hours) GREENBRIER VA-Albemarle-ATLAS14 10-Year Duration=5 min, Inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 14 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Subcatchment 1S: POST-B Time Runoff Time Runoff Time Runoff Time Runoff (hours) (cfs) (hours) (cfs) (hours) (cfs) (hours) (cfs) ' 0.00 0.00 0.52 0.00 1.04 0.00 1.56 . 0.00 0.01 0.37 0.53 0.00 1.05 0.00 1.57 ' 0:00 0.02 0.73 0.54 0.00 1.06 0.00 1.58 0.00 0.03 1.10 0.55 0.00 1.07 0.00 1.59 0.00 0.04 1.46 0.56 0.00 1.08 0.00 1.60 0.00 0.05 1.83 0.57 0.00 1.09 0.00 1.61 0.00 0.06 2.20 0.58 0.00 1.10 0.00 1.62 0.00 0.07 2.56 0.59 0.00 1.11 0.00 1.63 0.00 0.08 2.93 0.60 0.00 1.12 0.00 1.64 0.00 0.09 2.93 0.61 0.00 1.13 0.00 1.65 0.00 0.10 2.75 0.62 0.00 1.14 0.00 1.66 0.00 0.11 2.56 0.63 0.00 1.15 0.00 1.67 0.00 0.12 2.38 0.64 0.00 1.16 0.00 1.68 0:00 0.13 2.20 0.65 0.00. 1.17 0.00 1.69 0.00 0.14 2.01 0.66 0.00 1.18 . 0.00 1.70 0.00 0.15 1.83 0.67 0.00 1.19 0.00 1.71 0.00 0.16 1.65 0.68 0.00 1.20 0.00 1.72 0.00 0.17 1.46 0.69 0.00 1.21 0.00 1.73 0.00 0.18 1.28 0.70 0.00 1.22 0.00 1.74 0.00 0.19 1.10 0.71 '0.00 1.23 0.00 1.75 0.00 0.20 0.92 0.72 0.00 1.24 0.00 1.76 0.00 0.21 0.73 0.73 i 0.00 1.25 0.00 1.77 0.00 0.22 0.55 0.74 0.00 1.26 0.00 1.78 0.00 0.23 0.37 0.75 0.00 1.27 0.00 1.79 0.00 0.24 0.18 0.76 ' 0.00 1.28 0.00 1.80 0.00 0.25 0:00 0.77 0.00 1.29 0.00 1.81 0.00 0.26 0.00 0.78 0.00 1.30 0.00 1.82 0.00 0.27 0.00 0.79 0.00 1.31 0.00 1.83 0.00 0.28 0.00 0.80 0.00 1.32 0.00 1.84 0.00 0.29 0.00 0.81 0.00 1.33 0.00 1.85 0.00 0.30 0.00 0.82 0.00 1.34 0.00 1.86 0.00 0.31 0.00 0.83 0.00 1.35 0.00 1.87 0.00 0.32 0.00 0.84 0.00 1.36 0.00 1.88 0.00 0.33 0.00 0.85 0.00 1.37 0.00 1.89 0.00 0.34 0.00 0.86 0.00 1.38 0.00 1.90 0.00 0.35 0.00 0.87 0.00 1.39 0.00 1.91 0.00 0.36 0.00 0.88 0.00 1.40 0.00 1.92 0.00 0.37 0.00 0.89 0.00 1.41 0.00 1.93 0.00 0.38 0.00 0.90 0.00 1.42 0.00 1.94 0.00 0.39 0.00 0.91 0.00 1.43 0.00 1.95 0.00 0.40 0.00 0.92 0.00 1.44 0.00 1.96 0.00 0.41 0.00 0.93 0.00 1.45 0.00 1.97 0.00 0.42 0.00 0.94 0.00 1.46 0.00 1.98 0.00 0.43 0.00 0:95 0.00 1.47 0.00 1.99 0.00 0.44 0.00 0.96 0.00 1.48 0.00 2.00 0.00 0.45 0.00 0.97 0.00 1.49 0.00 0.46 0.00 0.98 0.00 1.50 0.00 0.47 0.00 0.99 0.00 1.51 0.00 0.48 0.00 1.00 0.00 1.52 0.00 0.49 0.00 1.01 0.00 1.53 0.00 0.50 0.00 1.02 0.00 1.54 0.00 0.51 0.00 1.03 0.00 1.55 0.00 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, Inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 15 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Inflow Area = 30,492 sf, Inflow Depth = 0.54" for 10-Year event Inflow = 2.97 cfs @ 0.09 hrs, Volume= 1,370 cf Outflow = 1.13 cfs @ 0.19 hrs, Volume= 1,371 cf, Atten= 62%, Lag= 6.2 min Primary = 1.13 cfs @ 0.19 hrs, Volume= 1,371 cf Routing by Stor-Ind method, Time Span= 0.00-2.00 hrs, dt= 0.01 hrs Peak Elev= 486.91' @ 0.19 hrs Surf.Area= 314 sf Storage= 716 cf Plug-Flow detention time= 7.4 min calculated for 1,364 cf (100% of inflow) Center-of-Mass det. time= 7.5 min ( 14.1 -6.7) Volume Invert Avail.Storaqe Storage Description #1 484.09'. 1,037 cf 48.0"D x 82.50'L Horizontal Cylinder S= 0.0050 '/' Device Routing Invert Outlet Devices #1 Primary 484.09' 15.0" x 13.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 483.00' S= 0.0838 '/' Cc= 0.900 n= 0.013 #2 Device 1 484.09' 0.38'W x 0.38' H Vert. Orifice/Grate C= 0.600 #3 Device 1 488.09' 2.0' long x 4.0' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 0.50' Rise . #4 Primary 488.59' 5.7' long x 4.5' high Sharp-Crested Rectangular Weir 2 End Contraction(s) 1.50' Rise Primary OutFlow Max=1.13 cfs @ 0.19 hrs HW=486.91' (Free Discharge) Culvert (Passes 1.13 cfs of 8.75 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.13 cfs @ 7.8 fps) 3=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) -4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 1 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 16 1 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC - 3/9/2006 Pond 5P: SWM B Hydrograph / (19 Inflow 2.97 ns s 009 nrsl 0 Primary oTi) Inflow Area=30,492 sf 3- 1' .,11 Inflow=2.97 cfs @ 0.09 hrs ? Primary=1.13 cfs @ 0.19 hrs 3 Peak Elev=486.91' ;;, f Storage=716 cf - ffa >u, 11.10 cfs c•0.19 hrs I t - . .. - _ ._ -. ..- 0 1 2 Time (hours) Pond 5P: SWM B Stage-Discharge 490 0 Primary i�� iShifirtW ied,ReaiiktOler,We7r.' ,i4 ___ ?Sharp-Qiested RectangulauiWeI ... .. .. .. - .. .. 488 is 0 • 487 . . - W 486. 485- % _ ,GJViilf1EQfifios rates J 0 . 1 . . . 30 35 . 4 5 10 5 20 25 0 Discharge (cfs) GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, Inten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 17 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Stage-Area-Storage 490- O Storage 489- . . .. 488- /17 487- w .. . . .. .... .......... .........: ... 486--. // �/OSo/ - 485- itlorizo it O -g"d'e_t • 0 100 200 300 400 500 600 700 800 900 1,000 Storage(cubic-feet) ' 0 ( ca) o -• N co (pm , II I� -2 C E 0 O 111 m o U j Q co r C s a co▪ o '0 ▪ cn C J O N C- 0w O V N O I M r V I• 0 r N N M N N O O I V' N O IC O V r a D (DM O1"c y N 0 0O NNO N M V f - N I• co n' 03N.... 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I- NUll N 4Q 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Q 2 M E50000000000000000000000000000000000000000000000000000 C.a) 0) 0 n_ run a _co a.< a. 0 w 0 0 C;m m m m m m m m m m m m m m m m m m m m 0 m m m m m m m m m m m m m m m m m 0 m m m m m m m m m m m m m 0 o I.- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Q C . ni a > --coo TF mmmmcommo ni Ti mmcoma�ocmmmmmmoo ni mommacommmcoo Ti mmooc000`toa`rocooamoamoommc`rommocoommcocoocom jU = L w vvvvvTtntm , mTI- vvvvvvvvvvvvvvvvvvvvvvvv Timni- vvvvv mo C) 0 0 0 ---0000000000000000000000000000000000000000000000000000 N s- N N 0 > O o m I co .O rc ap m O )L o C O 3 0 0 0 0 0 0 0 0 0 0 0 0 0 o o o 0 0 0 o 0 0 0 0 0 0 0 0 0 0 0 o 0 o 0 0 0 0 O 0 0 0 0 0 0 0 0 0 0 0 0 0 p 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ()J Qr O C O o 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 fln LL Z 0 < W@ 0 o^v in CD r CO CD O •- N t+) V u) CO I,-00 CD 0 N eh Tr In t0 n CO CD 0 N O) V In to n CO m 0 N P7 v LO CD I` CO m 0 N M v inW Q O E N 000000 cmNNNNNNNNN ch ch el m cu. a) ch 0) el M V Tr Tr vvv Tr V Tr Tru) u1 tDtototo W N v F p (7a. x GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=5 min, lnten=6.65 in/hr Prepared by Alan Franklin; Terra Concepts Page 21 HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 1 Hydrograph for Pond 5P: SWM B (continued) Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 1.56 0.00 0 484.09 0.00 1.57 0.00 0 484.09 0.00 1.58 0.00 0 484.09 0.00 1.59 0.00 0 484.09 0.00 1.60 0.00 0 484.09 0.00 1.61 0.00 0 484.09 0.00 1.62 0.00 0 484.09 0.00 1.63 0.00 0 484.09 0.00 1.64 0.00 0 484.09 0.00 1.65 0.00 0 484.09 0.00 1.66 0.00 0 484.09 0.00 1.67 0.00 0 484.09 0.00 1.68 0.00 0 484.09 0.00 1.69 0.00 0 484.09 0.00 1.70 0.00 0 484.09 0.00 1.71 0.00 0 484.09 0.00 1.72 0.00 0 484.09 0.00 1.73 0.00 0 484.09 0.00 1.74 0.00 0 484.09 0.00 1.75 0.00 0 484.09 0.00 1.76 0.00 0 484.09 0.00 1.77 0.00 0 484.09 0.00 1.78 0.00 0 484.09 0.00 1.79 0.00 0 484.09 0.00 1.80 0.00 0 484.09 0.00 1.81 0.00 0 484.09 0.00 1.82 0.00 0 484.09 0.00 1.83 0.00 0 484.09 0.00 1.84 0.00 0 484.09 0.00 1.85 0.00 0 484.09 0.00 1.86 0.00 0 484.09 , 0.00 1.87 0.00 0 484.09 0.00 1.88 0.00 0 484.09 0.00 1.89 0.00 0 484.09 0.00 1.90 0.00 0 484.09 0.00 1.91 0.00 0 484.09 0.00 1.92 0.00 0 484.09 0.00 1.93 0.00 0 484.09 0.00 1.94 0.00 0 484.09 0.00 1.95 0.00 0 484.09 0.00 1.96 0.00 0 484.09 0.00 1.97 0.00 0 484.09 0.00 1.98 0.00 0 484.09 0.00 1.99 0.00 0 484.09 0.00 2.00 0.00 0 484.09 0.00 GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=14 min, Inten=3.56 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Critical Duration Analysis / Elevation l Inflow {a^m C]Pnmary b * Si, i 4 -'14 r. . . . .. . ... ... u 86 it 'C � *' x LL q y $ 6 AMR $ ¢ 485 ,r " �'.3t +'r. s :W' law tt>��y�d'�� 0 5 10 15 20 25 30 35 40 45 50 55 60 55 70 75 80 85 90 95 100 105 110 115 120 Event Duration (minutes) GREENBRIER VA-Albemarle-ATLAS14 2-Year Duration=14 min, Inten=3.56 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005.HydroCAD Software Solutions LLC 3/9/2006 Critical Duration Analysis for Pond 5P: SWM B Duration Elevation Inflow Primary (minutes) (feet) (cfs) (cfs) 5 486.26 2.32 0.98 10 486.57 1.89 1.05 15 486.61 1.58 1.06 20 486.52 1.36 1.04 25 486.36 1.20 1.00 30 486.18 1.08 0.96 35 486.00 0.98 0.91 40 485.82 0.90 0.86 45 485.65 0.83 0.81 50 485.50 0.78 0.77 55 485.37 0.73 0.72 60 485.25 0.69 0.68 65 485.15 0.65 0.65 70 485.07 0.62 0.62 75 484.99 0.59 0.59 80 484.93 0.56 0.56 85 484.88 0.54 0.54 90 484.83 0.51 0.51 95 484.79 0.49 0.49 100 484.75 0.47 0.47 105 484.72 0.46 0.46 110 484.69 0.44 0.44 115 484.67 0.43 0.43 120 484.64 0.41 0.41 GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=14 min, Inten=3.56 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Hydragraph / I01nfow /umm a.mm z, 40 Primary s 7,.it Inflow Area=30,492 sf • s Inflow=1.63 cfs @ 0.09 hrs � Primary=1.06 cfs @ 0.29 hrs '_ ti -A , Peak EIev=486.62' hoes.,arl . . Storage=623-cf it 114* Pt �® fr ibe 0 r ///////////////, ,/'/, ����///////// %%��//�////����//��y���0////, 0 2 Time )hours) GREENBRIER VA-Albemarle-ATLASI4 2-Year Duration=14 min, Inten=3.56 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 5P: SWM B Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.00 0.00 0 484.09 0.00 0.05 0.98 49 484.66 0.42 0.10 1.63 200 485.29 0.70 0.15 1.63 354 485.79 0.85 0.20 1.63 484 486.19 0.96 0.25 1.47 592 486.52 1.04 0.30 0.98 622 486.61 1.06 0.35 0:49 566 486.44 1.02 0.40 0.00 434 486.04 0.92 0.45 0.00 280 485.56 0.78 0.50 0.00 153 485.11 0.63 0.55 0.00 55 484.69 0.44 0.60 0.00 3 484.28 0.10 0.65 0.00 0 484.09 0.00 0.70 0.00 0 484.09 0.00 0.75 0.00 0 484.09 0.00 0.80 0.00 0 484.09 0.00 0.85 0.00 0 484.09 0.00 0.90 0.00 0 484.09 0.00 0.95 0.00 0 484.09 0.00 1.00 0.00 0 484.09 0.00 1.05 0.00 0 484.09 0.00 1.10 0.00 0 484.09 0.00 1.15 0.00 0 484.09 0.00 1.20 0.00 0 484.09 0.00 1.25 0.00 0 484.09 0.00 1.30 0.00 0 484.09 0.00 1.35 0.00 0 484.09 0.00 1.40 0.00 0 484.09 0.00 1.45 0.00 0 484.09 0.00 1.50 0.00 0 484.09 0.00 1.55 0.00 0 484.09 0.00 1.60 0.00 0 484.09 0.00 1.65 0.00 0 484.09 0.00 1.70 0.00 0 484.09 0.00 1.75 0.00 0 484.09 0.00 1.80 0.00 0 484.09 0.00 1.85 0.00 0 484.09 0.00 1.90 0.00 0 484.09 0.00 1.95 0.00 0 484.09 0.00 2.00 0.00 0 484.09 0.00 GREENBRIER VA-Albemarle-ATLAS14 10-Year Duration=17min, Inten=4.29in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Hydrograph opInflow 1"di irie i 0 Primary •f L Inflow Area=30,492 sf lit;I Inflow=1.97 cfs @ 0.09 firs 4 Primary=1.29 cfs @ 0.34 hrs CI Peak Elev=487.73' Storage=946 cf V. ke 41 OM WA A VP VA tri av 0 2 Time (hours) GREENBRIER VA-Albemarle-ATLAS1410-Year Duration=17min, Inten=4.29in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Pond 5P: SWM B Critical Duration Analysis on 1v�ro. — .. .. . El Primary 421,stv A, 3 4 �` xy t� Cr, �� .... . ... .. . .. ...... .. .. .. . __. __...... .__.. .. -487_ t. � r V%" .. cam u ac I,. __ $j� . WF 485 't1ti !#c a 7��� 'f nyibrti,,,�y�� 4' 1 '1,, .•'� ocl�'r( R 1ip 31�ry adr � k 1 11son- ao`t iti l Y4" r 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Event Duration (minutes) GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=17 min, Inten=4.29 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Critical Duration Analysis for Pond 5P: SWM B Duration Elevation Inflow Primary (minutes) (feet) (cfs) (cfs) 5 486.91 2.97 1.13 10 487.49 2.46 1.25 15 487.72 2.08 1.29 20 487.70 1.82 1.29 • 25 487.55 1.62 1.26 30 487.35 1.47 1.22 35 487.13 1.35 1.17 40 486.91 1.25 1.13 . 45 486.71 1.16 1.08 50 486.51 1.09 1.04 55 486.32 1.03 0.99 • 60 486.16 0.97 0.95 65 486.00 0.93 0.91 70 485.86 0.88 0.87 75 485.74 0.84 0.84 80 485.63 0.81 0.81 85 485.53 0.78 0.78 90 485.44 0.75 0.75 95 485.36 0.72 0.72 100 485.29 0.70 0.70 • 105 485.23 0.68 0.68 110 485.17 0.66 0.66 115 485.12 0.64 0.64 . 120 485.07 0.62 0.62 GREENBRIER VA-Albemarle-ATLASI4 10-Year Duration=17 min, Inten=4.29 in/hr Prepared by Alan Franklin; Terra Concepts HydroCAD®7.10 s/n 002893 ©2005 HydroCAD Software Solutions LLC 3/9/2006 Hydrograph for Pond 5P: SWM B Time Inflow Storage Elevation Primary (hours) (cfs) (cubic-feet) (feet) (cfs) 0.00 0.00 0 484.09 0.00 0.05 1.18 62 484.73 0.46 0.10 1.97 257 485.48 0.76 0.15 1.97 456 486.11 0.94 . 0.20 1.97 629 486.63 1.07 0.25 1.97 782 487.12 1.17 0.30 1.77 910 487.58 1.26 0.35 1.18 944 487.72 1.29 0.40 0.59 875 487.45 1.24 0.45 0.00 715 486.90 1.13 0.50 0.00 524 486.31 0.99 0.55 0.00 358 485.80 0.86 0.60 0.00 216 485.34 0.72 0.65 0.00 102 484.91 0.55 0.70 0.00 22 484.50 0.31 0.75 0.00 0 484.09 0.00 0.80 0.00 0 484.09 0.00 0.85 0.00 0 484.09 0.00 0.90 0.00 0 484.09 0.00 0.95 0.00 0 484.09 0.00 1.00 0.00 0 484.09 0.00 1.05 0.00 0 484.09 0.00 1.10 0.00 0 484.09 0.00 1.15 0.00 0 484.09 0.00 1.20 0.00 0 484.09 0.00 1.25 0.00 0 484.09 0.00 1.30 0.00 0 484.09 0.00 1.35 0.00 0 484.09 0.00 1.40 0.00 0 484.09 0.00 1.45 0.00 0 484.09 0.00 1.50 0.00 0 484.09 0.00 1.55 0.00 0 484.09 0.00 1.60 0.00 0 484.09 0.00 1.65 0.00 0 484.09 0.00 1.70 0.00 0 484.09 0.00 1.75 0.00 0 484.09 0.00 1.80 0.00 0 484.09 0.00 1.85 0.00 0 484.09 0.00 1.90 0.00 0 484.09 0.00 1.95 0.00 0 484.09 0.00 2.00 0.00 0 484.09 0.00