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HomeMy WebLinkAboutSDP200800074 Calculations Final Site Plan and Comps. 2008-04-25 Blue Ridge Cohousing Final Stormwater Calculations Located in: Albemarle County, Virginia Nall op vN T. rt EEL Project Number: 1770.0 Llc.No.035730 I Date: April 25, 2008 ��'q 041211438401k GAY AND NEEL, INC, frAo 1260 RADFORD STREET CHRISTIANSBURG,VIRGINIA 24073 (540)381-6011 FAX (540)381-2773 info@gayandneel.com www.gayandneel.com 10, Blue Ridge Cohousing TABLE OF CONTENTS INTRODUCTION DRAINAGE MAPS CALCULATIONS vio • Time of Concentration and Rational Method Weighted Runoff Coefficients • Albemarle County Modified Simple Method Worksheets • Proposed Biofiltration Sizing Summary • Bio-Filter Detail from Albemarle County Design Manual • Hydraflow Hydrograph Hydrologic Analysis • Watershed Model Schematic • Return Period Recap • Rainfall report • Biofilter 1 to 5 Design Summary • Biofilter 1 to 5 2-yr, 10-yr and 100-yr Water Surface Elevation (WSEL) Schematic taa • 2-yr Predevelopment, Postdevelopment and Routing Summary Report and HydrographsHydrographs • 10-yr Predevelopment, Postdevelopment and Routing Summary Report and HydrographsHydrographs • 100-yr Predevelopment, Postdevelopment and Routing Summary Report and HydrographsHydrographs • Weir Flow Calculations for Biofilter 1 to 5 Blue Ridge Cohousing INTRODUCTION Four bioretention filters proposed in the site development plan are designed with Cipoletti-type weir outlets. The bioretention filters are designed with the required flat floor area and to reduce postdevelopment 2-yr year storm peak flows to less than or equal to predevelopment peak levels. The bioretention areas are 18 inches in depth. The bio-filters maintain a minimum 1.0 foot freeboard when passing the 100-yr peak flow rate. The predevelopment and postdevelopment peak flow rates are summarized in the table below: Predevelopment and Postdevelopment Peak Flow Rate Summary Area Return Predevelopment Postdevelopment Routed Peak Net Decrease Period Peak Flow(cfs) Flow(cfs) (Increase)(cfs) 2-yr 1.69 0.30 1.39 1 10-yr 2.20 1.01 1.19 100-yr 2.88 0.19 2.69 2-yr 0.44 0.34 0.10 2 10-yr 0.58 0.61 (0.03) 100-yr 0.76 0.16 0.60 2-yr 1.37 0.89 0.48 3 10-yr 1.79 1.60 0.19 100-yr 2.34 2.02 0.32 2-yr 1.47 1.44 0.03 4 10-yr 1.92 1.93 (0.01) 100-yr 2.50 2.02 0.48 2-yr 1.27 0.50 0.78 5 10-yr 1.67 1.09 0.58 100-yr 2.19 0.18 2.01 Blue Ridge Cohousing DRAINAGE MAPS MIIIMIIMIMMIIIIIi Ve' / 6a 1/0_ 1111.1.1%I\7N\. ,,,,.4.,. e00/4" 622 BRI `\ 628 \\ 626 830 632 \\�. 0 E J o ‘, s ':'-,// \ 1� ` a♦ ,b ' P'.: - O too '1/4;'''''' AllaPik , ,. .:N:::,\,,,, ''.•, 14411°. 2 ,.41 1 ,5 \ co 4 '`��'.111 '' a A�� • ,♦♦♦ \\ \ c rii 114itefitt.: 1*-Pill.r1141116.- --.--- I ,4..,\III\Itik`. \ \ 4 kV '441111111k,,,,4444444,441.Nlikiiii.iiiip' '4", .. .1,i,-4 1110 r ❑ .-, , '--_— 4 Oie , 2 pop,,, a. : 'I? ',1''di Jo 1 A 34 ii lir i A III° 4P*-14O r 1441%%114-- ........ ._44.4)41111111111 \\,‘ Lo Lo f:s 110 ---•::-. I \ .4110111„.„0. s_. >. 7 662 iiiith. , .,1, ' :14. I ui Q F '�lip 'a © ;,�'� '��.ye01 :111/1: Li, it,:, i ii,* ,.... ,. _---,r---------- 'o s12 le, /y/ / ,, j, 6,e J s16....- I ` re CO 6x , U sx I ' a f 4. Tci U 632 I i� a g. g d Q 6to Cr . t` 1` 632 ET / ikill -Timl `o GAY AND NEEL, INC. Blue Ridge CoHousing DESIGNED: BLM 1 ,CIVIL ENGNEERING CHECKED: URDEYIIARCHITECTURE Predevelopment Drainage Area Map DRAWN: BLM G SCALE: 1"=100' C0 1260 Radford Street DATE: 04/07/08 Christiansburg, Virginia 24073 REVISED: X Phone: (540) 381-6011 Fax: (540) 381-2773 JOB NO. 1770 Email: into®goyandneel.com Albemarle County, Virginia SHEET 1 OF 1 I e4 V eiy#4's . , : . 11k Id / 7AAp .101116.P 044 '\ 7\ : . \#4 \ \ • k#,.. Alp,. 4 , , .. A \ \ \\ . ,....., W.& 4 • A*.v-.. \ \--s. \\\ ,,#).. .v1vv. ,*,..,t,;,,r4v-__ if D,,,) *iii.., n87.4,440).„4„ .44,\\ ,..,,, ..,, ,,,:::•iii__ _ _ _ . ,:Af.1111 , .,1 ,, ,4 .„, ,, ail ., I A , ,* ,4:,,4111 . :At, I SP, .' 111111 VA-*•,- - KV' VII 4.1144,1 ; 'in -fii.".. i *4' r4 i 74'-4 i 41 r- t4 liPm —44 A EPAP ' --- i . ... ,)'NE "' _._:.', - ...:,..... re sor-0-4171""°1' ---_-_____- .. di ill jrilikls's • I V,r ,„,*1:. ''''' , ' ::: tiers -;ii....4•V ,, , / .11 .1 r, 'IliAL II, P :::°:: 4;4::11T.‘,' / Iir ' V11111P... 'TIIIIII..nmm..........._______1—I."14°____ ... 2, / , .1.1_.,_. GAY AND NEEL, INC. Blue Ridge CoHousing DESIGNED: BLM CC CIVIL ENGINEERING CHECKED: § V LANDSCAPE ARCHITECTURE Post Development Drainage Area Map DRAWN: BLM E SURVEYING SCALE: 1"=100' 0 1260 Radford Street DATE: 04/07/08 Christiansburg, Virginia 24073 REVISED JOB NO. 1770 Phone: (540) 381-6011 Fax: (540) 381-2773 Email: infoOgayandneel.com Albemarle County, Virginia SHEET 1 OF 1 Blue Ridge Cohousing CALCULATIONS Blue Ridge Cohousing Time of Concentration and Rational Method Weighted Runoff Coefficients Blue Ridge CoHousing JN: 1770.0 Pre-Development Drainage Area 1 BY: BLM DATE: 04/15/08 Drainage Area Area (ac.) C Area*C Comments 0.14 0.80 0.11 Gravel 0.03 0.90 0.03 Impervious 0.87 0.30 0.26 Pasture/Pre-Dev Grass 0.04 0.25 0.01 Woods Total Area 1.08 acres Weighted C 0.38 Area*C 0.41 Time of Concentration tOveriand 9.51 L= 200' H= 17.0 C'= 0.35 tChannel 0.33 L= 59' H= 12' tc 10.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 4.12 in/hr 2 49.02 10.50 0.82 110 5.37 in/hr 10 46.95 9.50 0.73 1100 7.01 in/hr 100 31.09 5.00 0.55 Results 02 1.69 cfs 010 2.20 cfs Q100 3.60 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Pre-Development Drainage Area 2 BY: BLM DATE: 04/08/08 Drainage Area Area (ac.) C Area*C Comments 0.02 0.80 0.02 Gravel 0.00 0.90 0.00 Impervious 0.33 0.30 0.10 Pasture/Pre-Dev Grass 0.00 0.25 0.00 Woods Total Area 0.35 acres Weighted C 0.33 Area *C 0.12 Time of Concentration tovedand 11.51 L= 200' H= 14.0 C'= 0.30 tChannel 0.11 L= 10' H= 1' tc 12.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 3.82 in/hr 2 49.02 10.50 0.82 110 5.00 in/hr 10 46.95 9.50 0.73 1100 6.54 in/hr 100 31.09 5.00 0.55 Results 02 0.44 cfs Q10 0.58 cfs Q100 0.94 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Pre-Development Drainage Area 3 BY: BLM DATE: 04/08/08 Drainage Area Area (ac.) C Area*C Comments 0.11 0.80 0.09 Gravel 0.12 0.90 0.11 Impervious 0.47 0.30 0.14 Pasture/Pre-Dev Grass 0.02 0.25 0.01 Woods Total Area 0.72 acres Weighted C 0.48 Area* C 0.34 Time of Concentration tovedand 10.97 L= 200' H= 8.0 C'= 0.35 tChannel 0.24 L= 35' H= 6' tc 11.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 3.96 in/hr 2 49.02 10.50 0.82 110 5.18 in/hr 10 46.95 9.50 0.73 1100 6.77 in/hr 100 31.09 5.00 0.55 Results 02 1.37 cfs Qio 1.79 cfs Q100 2.92 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Pre-Development Drainage Area 4 BY: BLM DATE: 04/07/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.08 0.90 0.07 Impervious 0.91 0.30 0.27 Pasture/Pre-Dev Grass 0.03 0.25 0.01 Woods Total Area 1.02 acres Weighted C 0.35 Area*C 0.35 Time of Concentration toverland 10.00 L= 200' H= 13.0 C'= 0.35 tchannel 0.47 L= 75' H= 10' t, 10.00 min Intensity I=B/(tc+D)AE Storm Frequency B D E 12 4.12 in/hr 2 49.02 10.50 0.82 110 5.37 in/hr 10 46.95 9.50 0.73 1100 7.01 in/hr 100 31.09 5.00 0.55 Results Q2 1.47 cfs Qio 1.92 cfs 0100 3.13 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Pre-Development Drainage Area 5 BY: BLM DATE: 04/08/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.13 0.90 0.12 Impervious 0.48 0.30 0.14 Pasture/Pre-Dev Grass 0.35 0.25 0.09 Woods Total Area 0.96 acres Weighted C 0.36 Area*C 0.35 Time of Concentration tOverland 12.80 L= 200' H= 8.0 C'= 0.30 tChannel 0.26 L= 30' H= 3' to 13.00 min Intensity I=B/(tc+D)^E Storm Frequency B D E 12 3.68 in/hr 2 49.02 10.50 0.82 110 4.84 in/hr 10 46.95 9.50 0.73 1100 6.34 in/hr 100 31.09 5.00 0.55 Results Q2 1.27 cfs Q10 1.67 cfs 0100 2.74 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Post-Development Drainage Area 1 BY: BLM DATE: 04/15/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.45 0.90 0.41 Impervious 0.59 0.30 0.18 Grass 0.04 0.25 0.01 Woods Total Area 1.08 acres Weighted C 0.55 Area* C 0.59 Time of Concentration toveriand 6.05 L= 200' H= 17.0 C'= 0.55 tchannel 0.29 L= 50' H= 10' tc 6.00 min Intensity I=B/(tc+D)^E Storm Frequency B D E 12 4.92 in/hr 2 49.02 10.50 0.82 110 6.35 in/hr 10 46.95 9.50 0.73 1100 8.31 in/hr 100 31.09 5.00 0.55 Results Q2 2.92 cfs Q,o 3.77 cfs Q1oo 6.17 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Post Development Drainage Area 2 BY: BLM DATE: 04/07/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.13 0.90 0.12 Impervious 0.22 0.30 0.07 Grass 0.00 0.25 0.00 Woods Total Area 0.35 acres Weighted C 0.52 Area *C 0.18 Time of Concentration tOveriand 5.87 L= 175' H= 13.0 C'= 0.55 tchannel 0.00 L= 0' H= 0' tc 6.00 min Intensity 1=B/(tc+D)"E Storm Frequency B D E 12 4.92 in/hr 2 49.02 10.50 0.82 110 6.35 in/hr 10 46.95 9.50 0.73 1100 8.31 in/hr 100 31.09 5.00 0.55 Results Q2 0.90 cfs 010 1.16 cfs 0100 1.89 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Post-Development Drainage Area 3 BY: BLM DATE: 04/07/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.40 0.90 0.36 Impervious 0.31 0.30 0.09 Grass 0.02 0.25 0.01 Woods Total Area 0.73 acres Weighted C 0.63 Area*C 0.46 Time of Concentration tOverland 10.16 L= 130' H= 3.0 C'= 0.35 tChannel 0.72 L= 80' H= 4' tc 11.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 3.96 in/hr 2 49.02 10.50 0.82 110 5.18 in/hr 10 46.95 9.50 0.73 1100 6.77 in/hr 100 31.09 5.00 0.55 Results 02 1.82 cfs Q10 2.38 cfs 0100 3.89 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Post Development Drainage Area 4 BY: BLM DATE: 04/07/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.23 0.90 0.21 Impervious 0.76 0.30 0.23 Grass 0.03 0.25 0.01 Woods Total Area 1.02 acres Weighted C 0.43 Area*C 0.44 Time of Concentration tOverland 2.96 L= 110' H= 8.0 C'= 0.90 tchannel 1.11 L= 140' H= 7' tc 5.00 min Intensity 1=B/(tc+D)AE Storm Frequency B D E 12 5.18 in/hr 2 49.02 10.50 0.82 110 6.67 in/hr 10 46.95 9.50 0.73 1100 8.76 in/hr 100 31.09 5.00 0.55 Results 02 2.27 cfs 010 2.92 cfs 0100 4.80 cfs Q = C*I*A Blue Ridge CoHousing JN: 1770.0 Post Development Drainage Area 5 BY: BLM DATE: 04/07/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.33 0.90 0.30 Impervious 0.37 0.30 0.11 Grass 0.26 0.25 0.07 Woods Total Area 0.96 acres Weighted C 0.49 Area* C 0.47 Time of Concentration toverland 3.39 L= 140' H= 8.5 C'= 0.90 tchannel 0.00 L= 0' H= 0' tc 5.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 5.18 in/hr 2 49.02 10.50 0.82 110 6.67 in/hr 10 46.95 9.50 0.73 1100 8.76 in/hr 100 31.09 5.00 0.55 Results 02 2.44 cfs 010 3.14 cfs 0100 5.15 cfs Q =C*I*A Blue Ridge Cohousing Albemarle County Modified Simple Method Worksheets Short Version BMP Computations For Worksheets 2 -6 Albemarle County Water Protection Ordinance: Modified Simple Method Plan: Blue Ridge Cohousing JN 1770.0 Water Resources Area: Drinking Water Watershed Preparer: BLM Date: 08-Apr-08 Project Drainage Area Designation Area 1 L storm pollutant export in pounds, L=[P(Pj)Rv/12][C(A)2.72] "" Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 percent imperviousness P annual precipitation,43"in Albemarle -` A project area in acres in subject drainage area, A= 1.08 40888 sq ft C pollutant concentration, mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)127 .." RR required removal , L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item pre-development Area •ost-development Area Roads Len th Width subtotal Length Width subtotal �„ See"Other Impervious Areas" = 0i 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 .__ .O . ...._ __M. __ _ ,, 1._ 0 0 0 0 - Driveways Length Width no. subtotal Length Width _no. subtotal and walks 0 0 0 0 0 0 0 0 I.. ,,,_.w o 0 _ 0 0 0 0 _.__._,__*..o 61 2621 526.25 3 4959.15 4959.15 ,,„. Parking Lots 1 2 3 4 1 2 3 4 �. 0 _ 0 1764.23 _��___ 0 1764.23 Gravel areas Area ._ 0 Riding Area Area ; .__- ._..__ x 0.70= 5941.67 f __._ x 0.70= 0 Structures Area no. subtotal x Area no. subtotal See"Other Impervious Areas" r 0 of o 'Unit C 0 0 0' 0 0 0 Unit B 0 0 0 0 0L 0 Unit D O. 0 0 12181.76' - Actively-grazed pasture& Area Area , yards and cultivated turf 400-21.2'x 0.08= ' 3201.69 22343.93 x 0.08= j 1787.514 ;Active crop land Area Area .,.._..,._ ..... x0.25- 0 [ X ,.0.25. ._._ 0 ."0 ;Other Impervious Areas Unit A 0' Half of Existing Barn 696.86 Half of Existing Barn 696.86 Impervious Cover 22% __ ... �F I(pre) l(post) • Rv(post) V 7 0.46 33.0 New Development(For Development Areas,existing impervious cover<=20%) _ C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type 0.701400 20% 0.25 1.65 3.04 1.40 \ 46% Development Area 0,35 1 00.: ' ; 0%, 0.25 0.82 1.52 0.70 46% Drinking Water Watersheds _. 0.40- "1.00 ',4�/a 0.25 0.94 1.74 0.80 46% Other Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) - C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type fort ,,% 0-''' 0.25 1.65 3.04 ; 1.56 51%• Development Area 03 Y tt 0.25 0.82 1.52 0.82 54%j Drinking Water Watersheds ... __ 0 401 e z ° °h 0.25 0.94 1.74 0.94 - 54% Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB Short Version BMP Computations For Worksheets 2 -6 Albemarle County Water Protection Ordinance: Modified Simple Method Plan: Blue Ridge Cohousing JN 1770.0 Water Resources Area: Drinking Water Watershed Preparer: BLM Date: 08-Apr-08 Project Drainage Area Designation Area 2 L storm pollutant export in pounds, L=[P(Pj)Rv/12][C(A)2.72] Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 1 percent imperviousness P annual precipitation,43"in Albemarle a A project area in acres in subject drainage area, A= 0.35",25943 sq ft C pollutant concentration, mg/I or ppm target phosphorus f factor applied to RR V required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)/27 "` RR required removal , L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item i pre-development fArea .ost-development Area Roads Len th Width subtotal 1 Length Width subtotal See"Other Impervious Areas" 0 0' 0. i 0 0 I__. 0 0,... 0 I 1- L, 01_ 0 1O _O oI 3 _._. _ . 0 ,.. .... Driveways Length Width no. subtotal ,LengthWidth no. subtotal and walks i 0 0( 0' 0 0��- 0 0 0 See 0 0 0 0 0 0 0 0 Other Impervious Areas l 10 0 633.01 633.01 for Parking Lots 1 2 3 4 1 2 3 4 o ___. -1- 0 -0-T.._ 0 0 Gravel areas Area l 0 Riding Areaf Area x070= 954.09 x0.70= I 0 Structures Area no subtotal Area no. ---I---subtotal See"Other Impervious Areas" , 0 0' 0 0 0 0 [ 0. 0 r-----07--01---- .- Oi 0 _... 0 _ 5029.79, 5029.79 Atio Actively-grazed pasture& Area 1Area yards and cultivated turf = 14471.71x 0.08= 1157.731 9583.2x0.08= 1 766.656' crop land Area Area I.- I 1 ]x0.25= 0 E 'x0.25- pIli E Other Impervious Areas __ Impervious Cover ._ _..__ .. ' 1(pre) l(post) Rv(post): V 0.43 9.9 +; New Development(For Development Areas,existing impervious cover<=20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR [Area Type 070 1.. , x,20% 0.230.49 0.92 - 0.43 46% Development Area A35 '0,1.00.,3. 4)/0 0.17 0.19 0.46 0.27 59% Drinking Water Watersheds 0.47 -1.06,'- 0.17 0.21 0.53 0.31 59%,Other Rural Land *min.values _..__,.._,___.,_ _.._________...w Redevelopment(For Development Areas,existing impervious cover>20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR Area Type -� 70 0,901- ,� 2Q°l 0.23 0.49 0.92 ` 0.48 52%, Development Area rn S5. . ,, ., a «`z 6° 0.17 0.19 0.46 0.30 65%0 Drinking Water Watersheds r '�•' £. `" 4; 0.17 1 0.21 0.53 0.35 65% Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB Short Version BMP Computations For Worksheets 2 -6 Albemarle County Water Protection Ordinance: Modified Simple Method Plan: Blue Ridge Cohousing JN 1770.0 Water Resources Area: Drinking Water Watershed Preparer: BLM Date: 08-Apr-08 Project Drainage Area Designation Area 3 L storm pollutant export in pounds, L=[P(Pj)Rv/12 I[C(A)2.72] "" Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 percent imperviousness P annual precipitation,43"in Albemarle '` A project area in acres in subject drainage area, A= 0.72 47987 C pollutant concentration,mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)/27 RR required removal , L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item pre-development Area ost-development Area Roads Length Width subtotal Len•th Width subtotal 1 0 0 0 , O 0 0 x 0 0 _.._., 0 0 3t 0 0 p 0 I 0'' 0 Road 0 2042.28 Driveways Length Width no. subtotal Length Width no._ _ subtotal and walks Oi 01 0 0 0 0 0 0 l - 0 01 0 0 0 0 01 0, 0 _ 0 mm Walkways 1945.25 1945.25 Parking Lots 1 2 3 4 1 2 3 4 0 T 0 4146.04 0 4146.04 Gravel areas Area OiRiding Are _L _... Area t Area 1 x 0.70= 1 4911.19 _� ix 0.70= 0 Structures Area no. subtotal Area no. subtotal 01 __I)1371,__ 0 _ 0 r 0 0 _0, 0 0 0 0 0 __. 0, IExisting Structures 1 0 0 153.52 153.52 01 4122.36 ;Actively-grazed pasture& Area Area yards and cultivated turf 21-3-66-.Ilx 0.08= 1709.29 j 20986x 0.08= 1678.88 Active crop land AreaArea x 0.25 I...... __. :,.,.._. 0 ] lx 0.25= 0 Other Impervious Areas Pool area 5168.07 Pool Area 5168.07 Impervious Cover 38% • - Toj' I(pre) ((post) Rv(post) V 0.60 29.5 New Development(For Development Areas,existing impervious cover<=20%) C f I(pre)* Rv(pre) L(pre) L(post) RR %RR 1 Area Type • i 0.70 1 00 20%%% 0.39 3 1.74 1 2.64 0.91 34%i Development Area 0:35 ,.1 00 0%. 0.39 0.87 r 1.32 0.45 34% Drinking Water Watersheds 0.40 "'1 00 1•%` 0.39 0.99 j 1.51 0.52 ' 34%, Other Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) C f (pre)* re * Rv(pre) L(pre) L(post RR %RR Area Type (P ) (p ) (P ) (P_ 704 0 90 I Q° 0.39 ' 1.74- 2.64 1.08 Development Area )))))11)0'''i:)4),0)-42))).')'1,4,»): � )R:U 8 , O 0.39 0.87 1.32 0.58 �� Drinking Water Watersheds ),)° � , 0.39 0.99 1 51 0.67 L, '' Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB Short Version BMP Computations For Worksheets 2 -6 Albemarle County Water Protection Ordinance: Modified Simple Method Plan: Blue Ridge Cohousing JN 1770.0 Water Resources Area: Drinking Water Watershed Preparer: BLM Date: 08-Apr-08 . Project Drainage Area Designation Area 4 L storm pollutant export in pounds, L=[P(Pj)Rv/12 I[C(A)2.72 j Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 I percent imperviousness P annual precipitation,43"in Albemarle A project area in acres in subject drainage area, A= 1.02 38975 sq ft C pollutant concentration,mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)/27 RR required removal , L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) . Impervious Cover Computation(values in feet&square feet) Item pre-development Area .ost development Area 1 Roads Length Width subtotal Length Width subtotal • See"Other Impervious Areas" C 01 0 01 E 0 0 0 0 00 0 0 O 0_ _0, _ .. 11 _. i _. ._.. ,_.... _._. __..0 .....01, 1533.56 ,. Driveways Length Width no. subtotal Length Width no. subtotal and walks 00 O 0? 0 0 0 0 , See 0 0 i 0 i_ O 0 0 'Other Impervious Areas i 2254 09 2254.09 1 1 1180.15_ 1180.15 • ;Parking Lots 1 2 3 4 1 2 3 _ I 0T I T_ 0 2336.52 0 0 .,_.._2336.52 Gravel areas Area % Riding Area Area x 0.70= 0 i---_. x 0.70= I 0 A. Structures Area no. subtotal Area no. subtotal See"Other Impervious Areas" 1 i 67134 671.34 Unit D 0 0 0 11 50__4 504 Unit B 01 0 0 0t_., 0 01175 34 Unit A 0 0 0 4985.19 ' Actively grazed pasture& AreaI i Area yards and cultivated turf j 40885 2 x 0 08= 3270.81' 34411122.4 x 0.08= 2752.992 Active crop land Area ._..._..__ Area jx0.25= 0 L x0.25= 0 ,Other Impervious Areas Impervious Cover _.. I(pre) ((post) ' Rv(post) V 0.31 19.7 New Development(For Development f Areas,existing impervious cover<=20%) _ C .._. _ RR %RR Area Type (pre) Rv(pre) L(pre) L(post) ,t � 0 70 `�00 20% 0.23 1.44 1.94 _. 0.49 i 26%' Development Area _ 036 ` � fl1°Iu 0.19 00.136 0 91 0.44 40°10 other Water Watersheds O0k 04b . x&00 Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) C f I re Rv p L(pre) L(post) RR %RR Area (pre)* (P ),_ (p ) (p ) Type ..,,z,..,,,,,...._!,0 - 1- ,',00,,;..\-'0. 1 (3 0.23' 1.44 1.94 0.64 33% Development Area A4 8 86 0% 0.19 0.58 0.970.47 49% Drinking Water Watersheds fl 40 {)86: .� °• 0.19 0.66 1.11 0.54 49% Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB Short Version BMP Computations For Worksheets 2 -6 Albemarle County Water Protection Ordinance: Modified Simple Method Plan: Blue Ridge Cohousing JN 1770.0 Water Resources Area: Drinking Water Watershed Preparer: BLM Date: 08-Apr-08 Project Drainage Area Designation Area 5 L storm pollutant export in pounds, L=[P(Pj)Rv/12 I[C(A)2.72] '"" Rv mean runoff coefficient, Rv=0.05+0.009(1) Pj small storm correction factor,0.9 percent imperviousness P annual precipitation,43"in Albemarle "' A project area in acres in subject drainage area, A= 0.96 38975 sq ft C pollutant concentration,mg/I or ppm target phosphorus f factor applied to RR ✓ required treatment volume in cy,0.5"over imperv.area= A(I)43560(0.5/12)/27 RR required removal , L(post)-f x L(pre) %RR removal efficiency, RR100/L(post) Impervious Cover Computation(values in feet&square feet) Item pre-development Area post-development Area Roads Length Width subtotal Length Width subtotal See"Other Impervious Areas' 0 0 0 0 0 0[ 0 Oi ! 0 0 0 I _,_.. .., 0 0' _ _ .,.,..-_ 0 7840 8} Driveways Length Width no. subtotal l . (Length Width no. subtotal and walks µ 01 01 Hµ 0 F 01 di' 01 0 I See 0 0 0 01 l 1,, 0 00 Other Impervious Areas 3035 75 i 3035 75 292.83 292.831 .. Parking Lots 1 2 3 4 1 2 3 4 E L 0 3845.17 0 Riding _ _ Of__,e __., 1x0.70- ry Gravel areas Area �E Riding Area rn � Area � ��� _�___.,,..._._,._.__ 01 A. Structures Area no. subtotal Area no. subtotal . _ See"Other Impervious Areas" 1 0 0 Unit D [ o' -61-- o 1 0 0 Unit B 0 0 0 0 __..,._ 0 0 Unit A 0 0 0 0 '" Actively-grazed pasture& Area 1 i Area yards and cultivated turf 36271.1:x 0.08= 2901.691_ 27442.8�x 0.08= 2195.424 Active crop land Area Area � x025= 01 x0 .25= 0I '° Other Impervious Areas Existing House 2378.25"Existing House 750+450 2378.251 Impervious Cover 'r°,, I(pre) ((post) Rv(post)'; V 0.41 25.5 New Development(For Development Areas,existing impervious cover<=20%) C f I(pre)* Rv(pre) L(pre) L(post)- RR wl %RR Area Type -I,-.,;I•11.70. 1 00 2O°f; 0.23 1.36 L '2. -6 1.04 ;i .°jo; Development Area o 35 llIg 1 0( A1,,O% 0.23 0.6T 1201052 o Drinking Water Watersheds -WW D 40 1 00 ''v 1% 0.23 0.77 1.37 0.60 ._. _. _ „• � _ � ��;. Other Rural Land *min.values Redevelopment(For Development Areas,existing impervious cover>20%) C f I(pre)* Rv(pre) L(pre) I L(post) RR %RR Area Type fl � fly 0.23 1.36 2.39 1.17 1 49Jd; Development Area �5 (Y ,4,1„I ��0.4 0.23 0.67 1.20T 0.62T 52 03 Drinking Water Watersheds `v w Q 40 01,' ' 1 0.23 0.77 1.37 0.71 52Si Other Rural Land Interim Manual, Page 70 rev. 16 Feb 1998 GEB .40 Blue Ridge Cohousing Proposed Biofiltration Sizing Summary a a a 4.1 a a r a a Albemarle County Engineering Expedited Review Tables Page 14 of 17 Table 13: Water Quality BMP Facilities Water Quality BMP Measures(by credited removal rate)in Albemarle County Removal Applicable State Stnds and BMP Rate Spec.** remarks Grassed swale 15% 3.13 flat grade Detention basin(dry) 15% 3.08,3.01,3.02,3.03 Stormceptor 15% 3.15 requires approval on sheet flow,beyond WPO Voluntary stream buffers 20% preliminary plat requirements,rural subdivisions Water quality swale 35% 3.13,3.11 designed as biofilter Extended detention basin 35% 3.07,3.01,3.02,3.03,3.04 30hr drawdown 2WQV Retention basin I(pond) 40% 3.06,3.01,3.02,3.03,3.04 3WQV 2.5%of impervious area,underdrain Biofilter I(bioretention)*4- 50% 3.11,3.05,(3.01,3.02,3.03) requried,(can combine with basin) 3.08,3.01,3.02,3.03,3.04, Extended detention and marsh 50% 3.05 1WQV in shallow marsh Retention basin II(larger pond) 50% 3.07,3.01,3.02,3.03,3.04 4WQV Stormfilter 50% 3.15 Biofilter II(bioretention)00- 65% 3.11,3.05,(3.01,3.02,3.03) 5%of impervious area 3.06,3.01,3.02,3.03,3.04, Retention basin III(larger pond with wetlands) 65% 3.05 4WQV+wetland bench Filterra 65% 3.15 Sand filter 65% 3.15 porous pavers n/a reduces impervious area *Usually,soils in Albemarle County do not support filtration. Filters have imported media+underdrains. Filtration using native soils must provide soil test data. **Virginia Stormwater Management Handbook,see Ala below. Facilities must have all components(wetlands, forebays,etc)to be credited with full removal rates KEY TO STANDARDS AND SPECS 3.01 Earthen Embankments 3.02 Principal Spillways 3.03 Vegetated Emergency Spillway 3.04 Sediment Forebay AIN. 3.05 Landscaping 3.06 Retention Basins 3.07 Extended Detention Basin 3.08 Detention Basin 3.09 Constructed Wetlands 3.10 Infiltration Practices 3.11 Bio-Retention 3.12 Sand Filters 3.13 Grassed Swale 3.14 Vegetated Filter Strip 3.15 Manufactured BMP Systems S 41110 Biofilter Sizing Requirements Summary Flat Floor Total Total % of Imp Area Area Area Impervious BioFilter Area Required Area ID (sq ft) (ac) Area (sq ft) %RR Type Required (sq ft) 1 47232 1.08 22199 54 II 5.0 1110 2 15426 0.35 6479 59 II 5.0 324 3 31599 0.73 19275 44 I 2.5 482 4 44315 1.02 12851 40 I 2.5 321 5 41660 0.96 16664 44 I 2.5 417 Blue Ridge Cohousing Bio-Filter Detail from Albemarle County Design Manual iOUTLET 6"NON-14,RI{>RAIED /PROTECTION PVC PIPE ICI tNr ,--OVERFLOW DAYLIGHT----__ ` ) PROTECTION •1! STONE WEIR REBUILD AS NECESSARY BERM ..1:•,. BERM ) Tl {,�,, I I:, 3:1 SIDE I 'I I* SLOPES---, �\� I I I (MAX) I" "�--`+--�._! / TI� ---__ 4"-6 PERFORATED PVC PIPE SCHEDULE 40 OR APPROVED i I „......1_,_::::::„.. - / ECZUIVALEMT MACEO 20(t,O.C, I OUTLET - ,_L, PROTECTION/ I ( 1 { 5 1 ENERGY I I �.1�' DISSIPATER I I Y STORM I I .'o,-.. /r WATER.CHANNEL. b 0E a..1":: Jl 7. ir CLEAN-UT 1 E �/( TYP) \\S ct PLAN 43 p STONE d TOP OF AS WEIR REBUILD SIDE SLOPE REGRADED CD BERM —t NECESSARY TD 31 1(MAX) �, coLO \ —._ ..�. LUCK BIO-FILTER MIX I6 2'-0” \ OR TESTED AND APPROVE[5 (MIN) E(3li1VALENr 'di i i a� u) UNDE.RDRAIN:GRAM (AASHTOM43, C ORIGINAL SILT ±\\ /'/ co PROVIDE PIPES REMOVE SILT AND E ACROSS ENTIRE WIDTH SEDIMENT AFTER FINAL AT 20 FT O.C. STABILIZATION.REPLACE WITH LOAM OR GRANULAR Q '401E: PROFILE EARTH FILL. cn ✓ I-HE DISTANCE BETWEEN 0' CLEAN ITB WILL NOT EXCEED ,_TOP OP BERM ,0 FEET. CLEAR-OUT GAP co i 6"to 1' WlWATERTIG i fi"ILA}t I STONE ` 1i 4/ 1 WEIR _I., J��' �,,,�.I r �i*e�itXsY1F,e"cF I -.r3er--r-•7 _ ---•�i1291 J d MI 4L6"NON-PERFOFWTEDy - _ 1l N PVC PIPE W 1%MIN,SLOPE O 208 O.C. ---- LOAM OR GRANULAR �_ 4EARTHEILL. PVC LL PIP L %MMI`N,SLOPE CROSS SECTION 0 m 3 SILT TRAP RETROFIT TO BIO-FILTER O NOSCALE m U Q Five bioretention filters proposed in the site development plan are designed with cipoletti \. al type weir outlets. The bioretention filters are designed with the required flat floor area and o to reduce postdevelopment 2-yr year storm peak flows to less than or equal to predevelopment peak levels.The bio-filters maintain a minimum 1.0 foot freeboard when 3 passing the 100-yr peak flow rate. 0 I-- Ab GAY AND NEEL, INC. Blue Ridge CoHousing DESIGNED: BLM CIVIL ENGINEERING CHECKED: n V LANDSCAPE ARCHITECTURE DRAWN: BLM Cr SURVEYING SCALE: NTS T 1260 Radford Street DATE: 04/25/08 0 Christiansburg, Virginia 24073 Bio-Filter Detail REVISED: JOB NO. 1770.0 Phone: (540) 381-6011 Fox: (540) 381-2773 X Emoil: in/oOgayandneel.com Albemarle County, Virginia SHEET 1 OF I Blue Ridge Cohousing Hydraflow Hydrograph Hydrologic Analysis Watershed Model Schematic Hydraflow Hydrographs by Intelisolve v9.23 MIN 2 3 4 5 6 7 8 9 10 rjb ste, 40 AIN 11 tpi MIN illie 12 wis 13 Legend Hyd. Origin Description 14Alf 1 Rational PRE AREA 1 ma. 2 Rational PRE AREA 2 3 Rational PRE AREA 3 4 Rational PRE AREA 4 5 Rational PRE AREA 5 6 Mod.RationaPOST AREA 1 7 Mod.RationalPOST AREA 2 8 Mod.RationaPOST AREA 3 15 VI 9 Mod.RationalPOST AREA 4 4.20 10 Mod.RationaPOST AREA 5 11 Reservoir Area 1 Routed 12 Reservoir Area 2 Routed 13 Reservoir Area 3 Routed 14 Reservoir Area 4 Routed 15 Reservoir Area 5 Routed Project: JN 1770 BLM-REV.gpw Thursday, Apr 24, 2008 Hydrograph Return Period Recap Hydraflow Hydrographs by Intelisolve v9.23 Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph No. type Hyd(s) description (origin) 1-Yr 2-Yr 3-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr r . 1 Rational 1.690 2.204 2.877 PRE AREA 1 2 Rational 0.441 ------ 0.577 0.756 PRE AREA 2 " 3 Rational 1.369 1.789 2.338 PRE AREA 3 4 Rational 1.470 1.917 2.503 PRE AREA 4 me 5 Rational 1.273 1.672 2.192 PRE AREA 5 6 Mod.Rational 1.900 2.405 4.939 POST AREA 1 sr 7 Mod.Rational 0.511 0.642 1.513 POST AREA 2 8 Mod.Rational 1.620 1.886 3.112 POST AREA 3 9 Mod. Rational 1.644 1.964 3.843 POST AREA 4 MO 10 Mod.Rational 1.418 1.759 4.122 POST AREA 5 11 Reservoir 6 0.300 1.012 0.191 Area 1 Routed "' 12 Reservoir 7 0.341 0.610 0.159 Area 2 Routed 13 Reservoir 8 0.888 1.597 2.023 Area 3 Routed .iii. 14 Reservoir 9 1.435 1.933 2.023 Area 4 Routed 15 Reservoir 10 0.495 1.093 0.180 Area 5 Routed 40/0 AMP AIN ar .s. QUI WO MO Ali Proj. file: JN 1770 BLM-REV.gpw Thursday, Apr 17, 2008 Hydraflow Rainfall Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Return Intensity-Duration-Frequency Equation Coefficients(FHA) Period (Yrs) B D E (N/A) 1 0.0000 0.0000 0.0000 2 49.0200 10.5000 0.8200 3 0.0000 0.0000 0.0000 5 55.7100 11.5000 0.8000 10 46.9500 9.5000 0.7300 25 40.1100 7.7500 0.6600 50 35.6000 6.5000 0.6100 100 31.0900 5.0000 0.5500 File name:Albermarle.idf Intensity= B /(Tc+ D)^E Return Intensity Values(in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 5.18 4.12 3.44 2.97 2.63 2.36 2.14 1.97 1.82 1.70 1.59 1.50 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 5.91 4.79 4.05 3.53 3.13 2.83 2.58 2.38 2.21 2.06 1.94 1.83 10 6.67 5.37 4.55 3.97 3.54 3.21 2.94 2.72 2.54 2.38 2.24 2.12 25 7.48 6.01 5.10 4.47 4.01 3.65 3.36 3.13 2.93 2.76 2.61 2.48 50 8.02 6.44 5.48 4.82 4.34 3.97 3.67 3.42 3.22 3.04 2.89 2.75 100 8.76 7.01 5.98 5.29 4.79 4.40 4.09 3.83 3.62 3.43 3.27 3.13 Tc=time in minutes.Values may exceed 60. Precip.file name:Albermarle.pcp Rainfall Precipitation Table (in) Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 3.50 3.70 0.00 0.00 5.60 6.80 0.00 9.10 SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 INN Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Hydraflow IDF Curves IDF file: Albermarle.idf Intensity(in/hr) 14.00 14.00 100-Yr 12.00 12.00 10.00 10.00 25-Yr 8.00 8.00 10-Yr 6.00 6.00 5-Yr 4.00 4.00 2-Yr — 2.00 2.00 0.00 — 0.00 0 5 10 15 20 25 30 35 40 45 50 55 60 Time (min) Hydraflow Hydrographs 2007 Pond Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Pond No. 1 - Area 1 BioFilter Pond Data Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=628.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 628.50 1,144 0 0 0.50 629.00 1,452 647 647 1.00 629.50 1,777 806 1,453 1.50 630.00 2,116 972 2,425 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] • Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 1.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest El.(ft) = 629.50 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 0.00 0.00 0.00 0.00 Weir Type = Ciplti --- --- --- Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.500(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). • Stage(ft) Stage/Discharge Elev(ft) 2.00 630.50 ... 1.80 630.30 1.60 630.10 . 1.40 629.90 .. 1.20 629.70 1.00 629.50 0.80 629.30 "" 0.60 629.10 0.40 1 628.90 0.20 628.70 0.00 628.50 0.00 0.50 1.00 1.50 2.00 Total Q Discharge(cfs) Pond Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Pond No. 2 - Area 2 Biofilter Pond Data Contours-User-defined contour areas.Conic method used for volume calculation. Begining Elevation=630.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 630.50 353 0 0 0.50 631.00 467 204 204 1.00 631.50 595 265 469 1.50 632.00 738 333 802 - Culvert I Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] W Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 2.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest El.(ft) = 631.50 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 0.00 0.00 0.00 0.00 Weir Type = Ciplti --- --- --- - Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.500(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). Awt Stage(ft) Stage/ Discharge Elev(ft) 2.00 632.50 r. 1.80 - 632.30 1.60 - 632.10 1.40 631.90 a. 1.20 631.70 1.00 - 631.50 0.80 631.30 ... 0.60 631.10 0.40 630.90 . 0.20 630.70 a. 0.00 630.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Total Q Discharge(cfs) Pond Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Pond No. 3 - Area 3 Biofilter Pond Data Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=639.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cult) Total storage(cult) 0.00 639.50 494 0 0 0.50 640.00 710 300 300 1.00 640.50 940 411 711 1.50 641.00 1,185 530 1,241 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 2.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest El.(ft) = 640.50 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 0.00 0.00 0.00 0.00 Weir Type = Cipiti --- --- --- ' Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.500(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). a„ Stage(ft) Stage/Discharge Elev(ft) 2.00 641.50 "` 1.80 641.30 1.60 641.10 1.40 640.90 1.20 640.70 1.00 640.50 0.80 640.30 0.60 640.10 0.40 639.90 S 0.20 639.70 0.00 639.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 S Total Q Discharge(cfs) . Pond Report . Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Pond No. 4 - Area 4 Biofilter Pond Data Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=632.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 632.50 358 0 0 0.50 633.00 470 206 206 1.00 633.50 596 266 472 1.50 634.00 736 332 804 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 2.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest El.(ft) = 633.50 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 0.00 0.00 0.00 0.00 Weir Type = Ciplti --- --- --- Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.500(by Contour) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). ® Stage(ft) Stage/Discharge Elev(ft) 2.00 634.50 +.. 1.80 634.30 1.60 634.10 1.40 -"" 633.90 1.20 ..�'""'� - 633.70 1.00 633.50 0.80 633.30 0.60 633.10 0.40 632.90 0.20 632.70 0.00 632.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Total Q Discharge(cfs) Pond Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Pond No. 5 - Area 5 Biofilter Pond Data Contours-User-defined contour areas.Conic method used for volume calculation. Begining Elevation=643.50 ft Stage/Storage Table Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft) 0.00 643.50 467 0 0 0.50 644.00 975 353 353 1.00 644.50 1,490 612 964 1.50 645.00 2,033 877 1,842 Culvert/Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] - Rise(in) = 0.00 0.00 0.00 0.00 Crest Len(ft) = 1.00 0.00 0.00 0.00 Span(in) = 0.00 0.00 0.00 0.00 Crest El.(ft) = 644.50 0.00 0.00 0.00 No.Barrels = 0 0 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El.(ft) = 0.00 0.00 0.00 0.00 Weir Type = Ciplti --- --- --- Length(ft) = 0.00 0.00 0.00 0.00 Multi-Stage = No No No No Slope(%) = 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Wet area) Multi-Stage = n/a No No No TW Elev.(ft) = 0.00 Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s). r .r Stage(ft) Stage/ Discharge Elev(ft) 2.00 645.50 A.. 1.80 645.30 1.60 645.10 ar 1.40 ---"--- 644.90 1.20 644.70 1.00 644.50 41110 0.80 644.30 0.60 644.10 0.40 643.90 0.20 643.70 a 0.00 643.50 0.00 0.50 1.00 1.50 2.00 Total Q Discharge(cfs) • w N m N > O O CO N 00 C O co > > a> o d> ` w a O N fY NF W -C d a W rem a o cp T _ o a.r O � a = ar a T O L s F3 - b I "O C rr a o t o E(0 O 5. O 0 .. m w MIN O 4111111 o 1 10 of N O N j O N am U , =d o.5 L .11 MO W X'" CO CDCL L a W 2 CO p 0 0o 0 o a z m U 0 1 i � 0. 11 / , M N O N > O O O toC - O N ,. N d M > nm o `> d 0 W ,• / III O N EX d t 0 m a O Op O _ ; N .5 rx a Q i CZ t 3 I / 0 x 1 o O a in O O M O O• > O N k C]W C 0 cn z cn co O a0 d U , W V N L I O CO N co G) ° cm 1,.. j Q W rI N m o 0 ti O O g o1.3 cp z m U gip, 1 o I I I I I I N a_ Od M N > N > O O p N O -a-5 c)...1- c 0cn > L3 o > Q >, a> p o ? w co I-LLJ N Q L w N CY o, a o co o 73 2 ON o -'. p ct N L Q I T > N AVIV . C9 a L ID F- Cp Aar C b C Ai' a LO O O M E 0 o • o 0 .„ m L vy C 0 71, / 0 z 0 0 1- ▪U N O ) o-u U =Q o•= p CV� L a) .}r O m M 113 a) Q L j Q w fl i M m 0 ZO p Z o rn U IIV I I I I 1 I I I I co •O 0. 0- N m O > O O -0O N C O o- ;j C O O00 T - 3T .sopa> 3 O O :'` W _O ct N I—W N Q a W o 5 O = N .� 0 Coo - L > Q I Q .c 1o. T (0 -0 O 8 L 1f T = i F- O C z E 1 lb... i M E O O j O m W 7 C 0 t 0 F- . Z 1 -Si N,> O to W U 1, Q orO) N 1 L Q) f+ s a O 3 CO di- co 1 3 a) a L Q W W c 1 ilit J CO O O N- NZ O O O O o Z O y. m U 1110 I I I I 1 I I I I • O CL CL _ \ \ \ =S 'H - 0 /\ - - / / < _ £ e 2 co ƒ I if .1 . < } | 6 f f / f I R { \S ! {\ a « \j / . C 0 | CD / | [ m Z I ! r \ } { v ; , -6 a.) ! | /% {<o ! cp\ ! I i } I � � O_ CO | 1 | ir) | ca ` i L. I3 (It ± . ± I _I d 0 r- ,-- - \ 7 Z 70/ J —) I I I I I I ƒ a) 0.. E Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.23 00 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 0. 1 Rational 1.690 1 10 1,014 ---- PRE AREA 1 2 Rational 0.441 1 12 317 ---- PRE AREA 2 41111 3 Rational 1.369 1 11 903 ---- PRE AREA 3 4 Rational 1.470 1 10 882 ---- PRE AREA 4 +. 5 Rational 1.273 1 13 993 ---- PRE AREA 5 6 Mod.Rational 1.900 1 6 1,984 ---- POST AREA 1 7 Mod.Rational 0.511 1 6 681 ---- POST AREA 2 8 Mod. Rational 1.620 1 11 1,390 ---- POST AREA 3 9 Mod.Rational 1.644 1 5 1,233 ---- POST AREA 4 10 Mod. Rational 1.418 1 5 1,659 ---- POST AREA 5 11 Reservoir 0.300 1 22 366 6 629.70 1,844 Area 1 Routed "r" 12 Reservoir 0.341 1 24 188 7 631.64 560 Area 2 Routed 13 Reservoir 0.888 1 19 615 8 640.76 987 Area 3 Routed Aro 14 Reservoir 1.435 1 13 695 9 633.87 711 Area 4 Routed 15 Reservoir 0.495 1 22 649 10 644.78 1,456 Area 5 Routed .. a. 4.1 . .. as mew .. w. JN 1770 BLM-REV.gpw Return Period: 2 Year Thursday, Apr 17, 2008 . Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 1 PRE AREA 1 Hydrograph type = Rational Peak discharge = 1.690 cfs Storm frequency = 2 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 1,014 cuft Drainage area = 1.080 ac Runoff coeff. = 0.38* Intensity = 4.118 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.110 x 0.75)+(0.020 x 0.90)+(0.810 x 0.30)]/1.080 PRE AREA 1 Q (cfs) Q (cfs) Hyd. No. 1 -- 2 Year 2.00 2.00 o 1.00 1.00 dim 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 1 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 6 POST AREA 1 Hydrograph type = Mod. Rational Peak discharge = 1.900 cfs Storm frequency = 2 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 1,984 cuft Drainage area = 1.080 ac Runoff coeff. = 0.55* Intensity = 3.199 in/hr Tc by User = 6.00 min IDF Curve = Albermarle.idf Storm duration = 2.9 x Tc Target Q = 1.690 cfs Est. Req'd Storage= 740 cuft *� *Composite(Area/C)=[(0.460 x 0.90)+(0.480 x 0.35)]/1.080 POST AREA 1 Q (cfs) Q (cfs) Hyd. No. 6--2 Year 2.00 2.00 1.00 1.00 to 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 Time (hrs) -- Hyd No. 6 Mod. Rational Est. Storage = 740 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 11 Area 1 Routed Hydrograph type = Reservoir Peak discharge = 0.300 cfs Storm frequency = 2 yrs Time to peak = 0.37 hrs Time interval = 1 min Hyd. volume = 366 cuft Inflow hyd. No. = 6 - POST AREA 1 Max. Elevation = 629.70 ft Reservoir name = Area 1 BioFilter Max. Storage = 1,844 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 1 Routed Q (cfs) Hyd. No. 11 --2 Year Q (cfs) 2.00 2.00 l; I , i� , I�l I II II ( I 1 j l 1.00 1.00 iit 3 i j { `yf I i i I 0.00 _ ,____ . _ -... 0.00 0.0 0.2 0.3 0.5 0.7 0.8 1.0 1.2 1.3 1.5 1.7 Time (hrs) ----- Hyd No. 11 Hyd No. 6 Total storage used = 1,844 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 2 PRE AREA 2 Hydrograph type = Rational Peak discharge = 0.441 cfs Storm frequency = 2 yrs Time to peak = 0.20 hrs Time interval = 1 min Hyd. volume = 317 cuft Drainage area = 0.350 ac Runoff coeff. = 0.33* Intensity = 3.816 in/hr Tc by User = 12.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.100 x 0.75)+(0.500 x 0.30)]/0.350 PRE AREA 2 Q (cfs) Q (cfs) Hyd. No. 2 --2 Year 0.50 0.50 0.45 0.45 0.40 0.40 0.35 0.35 0.30 0.30 0.25 0.25 0.20 0.20 0.15 0.15 0.10 0.10 0.05 0.05 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 Hyd No. 2 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 7 POST AREA 2 Hydrograph type = Mod. Rational Peak discharge = 0.511 cfs Storm frequency = 2 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 681 cuft Drainage area = 0.350 ac Runoff coeff. = 0.52* Intensity = 2.808 in/hr Tc by User = 6.00 min IDF Curve = Albermarle.idf Storm duration = 3.7 x Tc Target Q = 0.440 cfs Est. Req'd Storage= 294 cuft Composite(Area/C)=[(0.270 x 0.35)+(0.330 x 0.90)]/0.350 POST AREA 2 Q (cfs) Hyd. No. 7--2 Year 0 (cfs) 1.00 1.00 0.90 0.90 0.80 0.80 0.70 0.70 0.60 0.60 0.50 0.50 0.40 ,,. ..,, 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 Time (hrs) Hyd No. 7 Mod. Rational Est. Storage = 294 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 12 Area 2 Routed Hydrograph type = Reservoir Peak discharge = 0.341 cfs Storm frequency = 2 yrs Time to peak = 0.40 hrs Time interval = 1 min Hyd. volume = 188 cuft Inflow hyd. No. = 7 - POST AREA 2 Max. Elevation = 631.64 ft Reservoir name = Area 2 Biofilter Max. Storage = 560 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 2 Routed Q (cfs) Hyd. No. 12 --2 Year Q (cfs) 1.00 1.00 0.90 0.90 0.80 0.80 0.70 0.70 0.60 0.60 0.50 —p= i—; — ` 0.50 ...f i i 0.40 ; I '' 0.40 ilk 0.30 0.30 4 I f I 0.20 - ( , 0.20 0.10 —111 0.10 Ia _ 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 Time (hrs) Hyd No. 12 Hyd No. 7 Total storage used = 560 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 3 PRE AREA 3 Hydrograph type = Rational Peak discharge = 1.369 cfs Storm frequency = 2 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 903 cuft Drainage area = 0.720 ac Runoff coeff. = 0.48* Intensity = 3.961 in/hr Tc by User = 11.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.820 x 0.30)+(0.090 x 0.75)+(0.190 x 0.90)]/0.720 a a PRE AREA 3 Q (cfs) Q (cfs) Hyd. No. 3 --2 Year 2.00 2.00 a a a 1.00 1.00 a 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 Hyd No. 3 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 8 POST AREA 3 Hydrograph type = Mod. Rational Peak discharge = 1.620 cfs Storm frequency = 2 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 1,390 cuft Drainage area = 0.730 ac Runoff coeff. = 0.63* Intensity = 3.523 in/hr Tc by User = 11.00 min F IDF Curve = Albermarle.idf Storm duration = 1.3 x Tc Target Q = 1.370 cfs Est. Req'd Storage= 332 cuft *Composite(Area/C)=[(0.480 x 0.35)+(0.620 x 0.90)]/0.730 a POST AREA 3 Q (cfs) Hyd. No. 8 2 Year Q (cfs) 2.00 2.00 a a 1.00 1.00 a 0.00 — - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 Time (hrs) --- Hyd No. 8 Mod. Rational Est. Storage = 332 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 13 Area 3 Routed Hydrograph type = Reservoir Peak discharge = 0.888 cfs Storm frequency = 2 yrs Time to peak = 0.32 hrs Time interval = 1 min Hyd. volume = 615 cuft Inflow hyd. No. = 8 - POST AREA 3 Max. Elevation = 640.76 ft Reservoir name = Area 3 Biofilter Max. Storage = 987 cuft Storage Indication method used. Exfiltration extracted from Outflow. a Area 3 Routed Q (cfs) Hyd. No. 13 -- 2 Year Q(cfs) 2.00 2.00 i 0 i 1.00 i —� Y� 1.00 I i I� . 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 Time (hrs) Hyd No. 13 Hyd No. 8 I Total storage used = 987 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 4 PRE AREA 4 Hydrograph type = Rational Peak discharge = 1.470 cfs Storm frequency = 2 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 882 cuft Drainage area = 1.020 ac Runoff coeff. = 0.35* Intensity = 4.118 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.230 x 0.25)+(0.600 x 0.30)+(0.070 x 0.90)]/1.020 PRE AREA 4 Q (cfs) Hyd. No. 4 -- 2 Year Q (cfs) 2.00 2.00 1.00 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 m..___ Hyd No. 4 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 9 POST AREA 4 Hydrograph type = Mod. Rational Peak discharge = 1.644 cfs Storm frequency = 2 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 1,233 cuft Drainage area = 1.020 ac Runoff coeff. = 0.43* Intensity = 3.748 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 2.5 x Tc Target Q = 1.470 cfs Est. Req'd Storage= 413 cuft *Composite(Area/C)=[(0.480 x 0.35)+(0.150 x 0.90)+(0.270 x 0.25)]/1.020 POST AREA 4 Q (cfs) Hyd. No. 9 --2 Year Q (cfs) 2.00 2.00 1.00 1.00 a 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 Time (hrs) Hyd No. 9 Mod. Rational Est. Storage =413 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 14 Area 4 Routed Hydrograph type = Reservoir Peak discharge = 1.435 cfs Storm frequency = 2 yrs Time to peak = 0.22 hrs Time interval = 1 min Hyd. volume = 695 cuft Inflow hyd. No. = 9 - POST AREA 4 Max. Elevation = 633.87 ft Reservoir name = Area 4 Biofilter Max. Storage = 711 cuft Storage Indication method used. Exfiltration extracted from Outflow. a a Area 4 Routed Q (cfs) Hyd. No. 14 --2 Year Q (cfs) 2.00 2.00 S i I I ; `► f I I I i , 1.00 I 1.00 a i I f i 00 _ 0.00 0.0 0.0 0 1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 0.5 0.5 0.6 Time (hrs) Hyd No. 14 Hyd No. 9 Total storage used = 711 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 5 PRE AREA 5 Hydrograph type = Rational Peak discharge = 1.273 cfs Storm frequency = 2 yrs Time to peak = 0.22 hrs Time interval = 1 min Hyd. volume = 993 cuft Drainage area = 0.960 ac Runoff coeff. = 0.36 Intensity = 3.682 in/hr Tc by User = 13.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 AYE PRE AREA 5 •• Q (cfs) Hyd. No. 5--2 Year Q (cfs) 2.00 2.00 tY by 38f 1.00 1.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 ----� Hyd No. 5 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 10 POST AREA 5 Hydrograph type = Mod. Rational Peak discharge = 1.418 cfs Storm frequency = 2 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 1,659 cuft Drainage area = 0.960 ac Runoff coeff. = 0.49 Intensity = 3.014 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 3.9 x Tc Target Q = 1.270 cfs Est. Req'd Storage= 676 cuft POST AREA 5 Q (cfs) Hyd. No. 10 --2 Year Q (cfs) 2.00 2.00 1.00 1.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 Time (hrs) Hyd No. 10 Mod. Rational Est. Storage = 676 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 15 Area 5 Routed Hydrograph type = Reservoir Peak discharge = 0.495 cfs Storm frequency = 2 yrs Time to peak = 0.37 hrs Time interval = 1 min Hyd. volume = 649 cuft Inflow hyd. No. = 10 - POST AREA 5 Max. Elevation = 644.78 ft Reservoir name = Area 5 Biofilter Max. Storage = 1,456 cuft Storage Indication method used. Area 5 Routed Q (cfs) Hyd. No. 15 -- 2 Year Q (cfs) 2.00 2.00 aii 1 11 1 lI II, 1.00 i' ; I I1 1.00 ' I I 1. V 1 11 ill1 .. I11l1I �3I I If ; I I I III, 0.00 0.00 0.0 0.3 0.7 1.0 1.3 1.7 2.0 2.3 2.7 Time (hrs) Hyd No. 15 Hyd No. 10 1 Total storage used = 1,456 cuft Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.23 ,.r Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cult) (ft) (cult) ar 1 Rational 2.204 1 10 1,322 ---- PRE AREA 1 2 Rational 0.577 1 12 416 ---- PRE AREA 2 is 3 Rational 1.789 1 11 1,181 ---- PRE AREA 3 4 Rational 1.917 1 10 1,150 ---- PRE AREA 4 °" 5 Rational 1.672 1 13 1,304 ---- ----- PRE AREA 5 6 Mod.Rational 2.405 1 6 2,771 ---- POST AREA 1 7 Mod.Rational 0.642 1 6 970POST AREA 2 8 Mod. Rational 1.886 1 11 2,116 ---- POST AREA 3 9 Mod. Rational 1.964 1 5 1,827 ---- POST AREA 4 Nis 10 Mod.Rational 1.759 1 5 2,375 ---- POST AREA 5 11 Reservoir 1.012 1 22 1,147 6 629.95 2,332 Area 1 Routed dill 12 Reservoir 0.610 1 25 473 7 631.70 604 Area 2 Routed 13 Reservoir 1.597 1 20 1,287 8 640.89 1,120 Area 3 Routed . 14 Reservoir 1.933 1 15 1,277 9 633.94 763 Area 4 Routed 15 Reservoir 1.093 1 24 1,356 10 644.98 1,799 Area 5 Routed WO ailt d. a. WO voir IWO +rr JN 1770 BLM-REV.gpw Return Period: 10 Year Thursday, Apr 17, 2008 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 1 PRE AREA 1 Hydrograph type = Rational Peak discharge = 2.204 cfs Storm frequency = 10 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 1,322 cuft Drainage area = 1.080 ac Runoff coeff. = 0.38* Intensity = 5.369 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.110 x 0.75)+(0.020 x 0.90)+(0.810 x 0.30)]/1.080 PRE AREA 1 Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs) 3.00 3.00 a a 2.00 2.00 a 1.00 1.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 9� �--- Hyd No. 1 Time (hrs) as Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 6 POST AREA 1 - Hydrograph type = Mod. Rational Peak discharge = 2.405 cfs Storm frequency = 10 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 2,771 cuft Drainage area = 1.080 ac Runoff coeff. = 0.55* Intensity = 4.049 in/hr Tc by User = 6.00 min ..a IDF Curve = Albermarle.idf Storm duration = 3.2 x Tc Target Q = 2.200 cfs Est. Req'd Storage= 1,061 cuft *Composite(Area/C)=[(0.460 x 0.90)+(0.480 x 0.35)]/1.080 a. POST AREA 1 Q (cfs) Hyd. No. 6 -- 10 Year Q (cfs) 3.00 3.00 a, a 2.00 2.00 " `. a 1.00 1.00 a 0.00 "- 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 Time (hrs) Hyd No. 6 I Mod. Rational Est. Storage = 1,061 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 11 Area 1 Routed Hydrograph type = Reservoir Peak discharge = 1.012 cfs Storm frequency = 10 yrs Time to peak = 0.37 hrs r. Time interval = 1 min Hyd. volume = 1,147 cuft Inflow hyd. No. = 6 - POST AREA 1 Max. Elevation = 629.95 ft Reservoir name = Area 1 BioFilter Max. Storage = 2,332 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 1 Routed Q (cfs) Hyd. No. 11 -- 10 Year 0 (cfs) 3.00 3.00 ; ; I 2.00 ; l r 2.00 v ri � ! iiil � j ! ! �� , ` l f � 1.00 1 1! I 1.00 i ! _ i 0.00 , . ,, ._ _, Il ,._,-...i _ 0.00 0.0 0.2 0.3 0.5 0.7 0.8 1.0 1.2 1.3 1.5 1.7 Time (hrs) ----- Hyd No. 11 Hyd No. 6 Total storage used = 2,332 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 2 PRE AREA 2 Hydrograph type = Rational Peak discharge = 0.577 cfs Storm frequency = 10 yrs Time to peak = 0.20 hrs Time interval = 1 min Hyd. volume = 416 cuft Drainage area = 0.350 ac Runoff coeff. = 0.33* Intensity = 5.000 in/hr Tc by User = 12.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.100 x 0.75)+(0.500 x 0.30)]/0.350 PRE AREA 2 Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs) 1.00 1.00 401 0.90 0.90 0.80 0.80 0.70 0.70 0.60 0.60 0.50 0.50 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 444, Hyd No. 2 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intel'solve v9.23 Thursday,Apr 17,2008 Hyd. No. 7 POST AREA 2 Hydrograph type = Mod. Rational Peak discharge = 0.642 cfs Storm frequency = 10 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 970 cuft Drainage area = 0.350 ac Runoff coeff. = 0.52* Intensity = 3.525 in/hr Tc by User = 6.00 min IDF Curve = Albermarle.idf Storm duration = 4.2 x Tc Target Q = 0.580 cfs Est. Req'd Storage= 414 cuft *Composite(Area/C)=[(0.270 x 0.35)+(0.330 x 0.90)]/0.350 POST AREA 2 .. Q (cfs) Q (cfs) Hyd. No. 7 -- 10 Year 1.00 1.00 0.90 0.90 0.80 0.80 0.70 0.70 1111111111111 0.60AIIIIMIIEEIIIIIIIIIIIIIMII0.60 0.50 0.50 K 0.40 II/ 0.40 0.30 rAilrA In 0.30 MK., 0.20 0.20 MK0.10 0.10 ,,,, , MK 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 0.5 0.5 Hyd No. 7 Mod. Rational Est. Storage = 414 cuft Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 12 Area 2 Routed Hydrograph type = Reservoir Peak discharge = 0.610 cfs Storm frequency = 10 yrs Time to peak = 0.42 hrs Time interval = 1 min Hyd. volume = 473 cuft Inflow hyd. No. = 7 - POST AREA 2 Max. Elevation = 631.70 ft Reservoir name = Area 2 Biofilter Max. Storage = 604 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 2 Routed — Q (cfs) Q (cfs) Hyd. No. 12 -- 10 Year 1.00 1.00 0.90 0.90 0.80 0.80 0.70 . 0.70 ::: — i -- ---�- 060i i i i 0.50 ilii 1 e - /__Jr-_F__Iil ` i 0.40 i 0.40 Ilii i , 0.30 —�! �� i I i 0.30 i _�i i i i j S 0.20 j ( �—�-- 0.20 0.10 i 0.10 . �� 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 Time (hrs) Hyd No. 12 Hyd No. 7 Total storage used = 604 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 3 PRE AREA 3 Hydrograph type = Rational Peak discharge = 1.789 cfs Storm frequency = 10 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 1,181 cuft Drainage area = 0.720 ac Runoff coeff. = 0.48* Intensity = 5.177 in/hr Tc by User = 11.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.820 x 0.30)+(0.090 x 0.75)+(0.190 x 0.90)]/0.720 PRE AREA 3 Q (cfs) Hyd. No. 3 -- 10 Year Q(cfs) 2.00 2.00 1.00 1.00 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 Time (hrs) - Hyd No. 3 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 8 POST AREA 3 Hydrograph type = Mod. Rational Peak discharge = 1.886 cfs Storm frequency = 10 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 2,116 cuft Drainage area = 0.730 ac Runoff coeff. = 0.63* Intensity = 4.102 in/hr Tc by User = 11.00 min IDF Curve = Albermarle.idf Storm duration = 1.7 x Tc Target Q = 1.790 cfs Est. Req'd Storage= 466 cuft *Composite(Area/C)=[(0.480 x 0.35)+(0.620 x 0.90)]/0.730 POST AREA 3 Q (cfs) Hyd. No. 8-- 10 Year Q (cfs) 2.00 2.00 a a 1.00 - 1.00 a a a a 0.00 — 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 0.5 Time (hrs) n---- - Hyd No. 8 Mod. Rational Est. Storage = 466 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 13 Area 3 Routed Hydrograph type = Reservoir Peak discharge = 1.597 cfs Storm frequency = 10 yrs Time to peak = 0.33 hrs Time interval = 1 min Hyd. volume = 1,287 cuft Inflow hyd. No. = 8 - POST AREA 3 Max. Elevation = 640.89 ft Reservoir name = Area 3 Biofilter Max. Storage = 1,120 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 3 Routed Q (cfs) Hyd. No. 13 -- 10 Year Q(cfs) 2.00 2.00 t i E i i I i i eji ; f ! € 9 i 41 � ! 1.00 - 11.00 f ' ; i € iI j e � ' ( iit 9 xids Ass 9 iiii � i 0.00 �--- 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 Time (hrs) Hyd No. 13 Hyd No. 8 Total storage used = 1,120 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 4 PRE AREA 4 Hydrograph type = Rational Peak discharge = 1.917 cfs Storm frequency = 10 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 1,150 cuft Drainage area = 1.020 ac Runoff coeff. = 0.35* Intensity = 5.369 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0 230 x 0.25)+(0.600 x 0.30)+(0.070 x 0.90)]/1.020 PRE AREA 4 Q (cfs) Hyd. No. 4 -- 10 Year Q (cfs) 2.00 2.00 1.00 — 1.00 • 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 Hyd No. 4 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 9 POST AREA 4 Hydrograph type = Mod. Rational Peak discharge = 1.964 cfs Storm frequency = 10 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 1,827 cuft Drainage area = 1.020 ac Runoff coeff. = 0.43* Intensity = 4.479 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 3.1 x Tc Target Q = 1.920 cfs Est. Req'd Storage= 553 cuft *Composite(Area/C)=[(0.480 x 0.35)+(0.150 x 0.90)+(0.270 x 0.25)]/1.020 POST AREA 4 Q (cfs) Q (cfs) Hyd. No. 9 -- 10 Year 2.00 2.00 1.00 1.00 y,r c'. 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 --�- Time (hrs) Hyd No. 9 Mod. Rational Est. Storage = 553 tuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 14 Area 4 Routed Hydrograph type = Reservoir Peak discharge = 1.933 cfs Storm frequency = 10 yrs Time to peak = 0.25 hrs Time interval = 1 min Hyd. volume = 1,277 cuft Inflow hyd. No. = 9 - POST AREA 4 Max. Elevation = 633.94 ft Reservoir name = Area 4 Biofilter Max. Storage = 763 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 4 Routed Q (cfs) Hyd. No. 14-- 10 Year Q (cfs) 2.001 I I i i 2.00 - \ i S 1.00 -- — 1.00 I I I , 11 ! l I i s Ilk , j I I i 0.00 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 Time (hrs) Hyd No. 14 Hyd No. 9 Total storage used = 763 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 5 PRE AREA 5 Hydrograph type = Rational Peak discharge = 1.672 cfs Storm frequency = 10 yrs Time to peak = 0.22 hrs Time interval = 1 min Hyd. volume = 1,304 cuft Drainage area = 0.960 ac Runoff coeff. = 0.36 Intensity = 4.837 in/hr Tc by User = 13.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 PRE AREA 5 Q (cfs) Hyd. No. 5 -- 10 Year Q (cfs) 2.00 2.00 /\\\ 1.00 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 Hyd No. 5 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 10 POST AREA 5 Hydrograph type = Mod. Rational Peak discharge = 1.759 cfs Storm frequency = 10 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 2,375 cuft Drainage area = 0.960 ac Runoff coeff. = 0.49 Intensity = 3.740 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 4.5 x Tc Target Q = 1.670 cfs Est. Req'd Storage= 919 cuft POST AREA 5 Q (cfs) Hyd. No. 10 -- 10 Year Q (cfs) 2.00 2.00 1.00 1.00 0.00 ' 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 Time (hrs) Hyd No. 10 Mod. Rational Est. Storage = 919 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 15 Area 5 Routed Hydrograph type = Reservoir Peak discharge = 1.093 cfs Storm frequency = 10 yrs Time to peak = 0.40 hrs Time interval = 1 min Hyd. volume = 1,356 cuft Inflow hyd. No. = 10 - POST AREA 5 Max. Elevation = 644.98 ft Reservoir name = Area 5 Biofilter Max. Storage = 1,799 cuft Storage Indication method used. Area 5 Routed Q (cfs) Q (cfs Hyd. No. 15 -- 10 Year ) 2.00 2.00 iilii�' lils ii I , II + f ill; 1111 I �lliil I It III li �`il Illfii .\ 1.00i i,; ; l• 1.00 ;liii iltl'+i1f �Il all iiii+ i � I iii . ,i i ' iiia I I'il l 0.00 sli', 11111111 ... - 0.00 0.0 0.2 0.3 0.5 0.7 0.8 1.0 1.2 1.3 1.5 1.7 1.8 2.0 2.2 Time (hrs) Hyd No. 15 Hyd No. 10 Total storage used = 1,799 cuft Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.23 wagHyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) NM 1 Rational 2.877 1 10 1,726 ---- PRE AREA 1 2 Rational 0.756 1 12 544 ---- PRE AREA 2 .. 3 Rational 2.338 1 11 1,543 ---- PRE AREA 3 4 Rational 2.503 1 10 1,502 ---- PRE AREA 4 5 Rational 2.192 1 13 1,710 ---- PRE AREA 5 6 Mod.Rational 4.939 1 6 1,778 ---- POST AREA 1 7 Mod.Rational 1.513 1 6 545 ---- POST AREA 2 woo 8 Mod.Rational 3.112 1 11 2,054 ---- POST AREA 3 9 Mod.Rational 3.843 1 5 1,153 ---- POST AREA 4 aur 10 Mod.Rational 4.122 1 5 1,237 ---- POST AREA 5 11 Reservoir 0.191 1 12 224 6 629.65 1,742 Area 1 Routed "' 12 Reservoir 0.159 1 11 64 7 631.58 523 Area 2 Routed 13 Reservoir 2.023 1 15 1,306 8 640.95 1,190 Area 3 Routed .1614 Reservoir 2.023 1 7 666 9 633.96 772 Area 4 Routed 15 Reservoir 0.180 1 10 270 10 644.65 1,214 Area 5 Routed r am ar .0 rr rr a. NO MO JN 1770 BLM-REV.gpw Return Period: 100 Year Thursday, Apr 17, 2008 Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 1 PRE AREA 1 Hydrograph type = Rational Peak discharge = 2.877 cfs Storm frequency = 100 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 1,726 cuft Drainage area = 1.080 ac Runoff coeff. = 0.38* Intensity = 7.011 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.110 x 0.75)+(0.020 x 0.90)+(0.810 x 0.30)]/1.080 PRE AREA 1 Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 -- Hyd No. 1 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 6 POST AREA 1 Hydrograph type = Mod. Rational Peak discharge = 4.939 cfs Storm frequency = 100 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 1,778 cuft Drainage area = 1.080 ac Runoff coeff. = 0.55* Intensity = 8.315 in/hr Tc by User = 6.00 min IDF Curve = Albermarle.idf Storm duration = 1.0 x Tc Target Q = 0.000 cfs Est. Req'd Storage= 0 cuft *Composite(Area/C)=[(0.460 x 0.90)+(0.480 x 0.35)]/1.080 POST AREA 1 Q (cfs) Hyd. No. 6 -- 100 Year Q (cfs) 5.00 5.00 A 4.00 4.00 3.00 3.00 2.00 2.00 1.00 ' 1.00 0.00 0.00 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.2 - - Hyd No. 6 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 11 Area 1 Routed Hydrograph type = Reservoir Peak discharge = 0.191 cfs Storm frequency = 100 yrs Time to peak = 0.20 hrs Time interval = 1 min Hyd. volume = 224 cuft Inflow hyd. No. = 6 - POST AREA 1 Max. Elevation = 629.65 ft Reservoir name = Area 1 BioFilter Max. Storage = 1,742 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 1 Routed Q (cfs) Q (cfs) Hyd. No. 11 -- 100 Year 5.00 5.00 4.00 4.00 3.00 ---- 3.00 i . ` il 2.00 L=- 2.00 I 1.00 1.00 0.00 f 0.0 0.2 0.3 0.5 0.7 0.8 1.0 1.2 1.3 1.5 Time (hrs) --��-- Hyd No. 11 Hyd No. 6 Total storage used = 1,742 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 2 PRE AREA 2 Hydrograph type = Rational Peak discharge = 0.756 cfs Storm frequency = 100 yrs Time to peak = 0.20 hrs Time interval = 1 min Hyd. volume = 544 cuft Drainage area = 0.350 ac Runoff coeff. = 0.33* Intensity = 6.544 in/hr Tc by User = 12.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.100 x 0.75)+(0.500 x 0.30)]/0.350 PRE AREA 2 Q (cfs) Hyd. No. 2-- 100 Year Q(cfs) 1.00 1.00 0.90 0.90 0.80 0.80 0.70 - 0.70 0.60 0.60 0.50 0.50 0.40 0.40 0.30 0.30 0.20 0.20 0.10 0.10 0.00 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 Hyd No. 2 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 7 POST AREA 2 Hydrograph type = Mod. Rational Peak discharge = 1.513 cfs Storm frequency = 100 yrs Time to peak = 0.10 hrs Time interval = 1 min Hyd. volume = 545 cuft Drainage area = 0.350 ac Runoff coeff. = 0.52* Intensity = 8.315 in/hr Tc by User = 6.00 min IDF Curve = Albermarle.idf Storm duration = 1.0 x Tc Target Q = 0.000 cfs Est. Req'd Storage= 0 cuft *Composite(Area/C)=[(0.270 x 0.35)+(0.330 x 0.90)]/0.350 POST AREA 2 Q (cfs) Q (cfs) Hyd. No. 7 -- 100 Year 2.00 2.00 1.00 — 1.00 0.00 0.00 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.2 Hyd No. 7 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 12 Area 2 Routed Hydrograph type = Reservoir Peak discharge = 0.159 cfs Storm frequency = 100 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 64 cuft Inflow hyd. No. = 7 - POST AREA 2 Max. Elevation = 631.58 ft Reservoir name = Area 2 Biofilter Max. Storage = 523 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 2 Routed Q (cfs) Hyd. No. 12 -- 100 Year Q(cfs) 2.00 2.00 1.00 — 1.00 I I I I i 0.00 �. ... .. .......1--.i 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 0.5 0.5 Time (hrs) Hyd No. 12 Hyd No. 7 Total storage used = 523 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 3 PRE AREA 3 Hydrograph type = Rational Peak discharge = 2.338 cfs Storm frequency = 100 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 1,543 cuft Drainage area = 0.720 ac Runoff coeff. = 0.48* Intensity = 6.766 in/hr Tc by User = 11.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 *Composite(Area/C)=[(0.820 x 0.30)+(0.090 x 0.75)+(0.190 x 0.90)]/0.720 PRE AREA 3 Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 Hyd No. 3 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 8 POST AREA 3 Hydrograph type = Mod. Rational Peak discharge = 3.112 cfs Storm frequency = 100 yrs Time to peak = 0.18 hrs Time interval = 1 min Hyd. volume = 2,054 cuft Drainage area = 0.730 ac Runoff coeff. = 0.63* Intensity = 6.766 in/hr Tc by User = 11.00 min IDF Curve = Albermarle.idf Storm duration = 1.0 x Tc Target Q = 0.000 cfs Est. Req'd Storage= 0 cuft *Composite(Area/C)=[(0.480 x 0.35)+(0.620 x 0.90)]/0.730 POST AREA 3 Q (cfs) Hyd. No. 8-- 100 Year Q (cfs) 4.00 4.00 3.00 . 3.00 2.00 2.00 1.00 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 �--- Hyd No. 8 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 13 Area 3 Routed Hydrograph type = Reservoir Peak discharge = 2.023 cfs Storm frequency = 100 yrs Time to peak = 0.25 hrs Time interval = 1 min Hyd. volume = 1,306 cuft Inflow hyd. No. = 8 - POST AREA 3 Max. Elevation = 640.95 ft Reservoir name = Area 3 Biofilter Max. Storage = 1,190 cuft Storage Indication method used. Exfiltration extracted from Outflow. a Area 3 Routed Q (cfs) Hyd. No. 13-- 100 Year Q (cfs) 4.00 4.00 3.00 — 3.00 2.00 --- -- 2.00 s 1.00 ---- -- 1.00 0.00 - . .__. _-� 0.00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 Time (hrs) — Hyd No. 13 Hyd No. 8 Total storage used = 1,190 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 4 PRE AREA 4 Hydrograph type = Rational Peak discharge = 2.503 cfs Storm frequency = 100 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 1,502 cuft Drainage area = 1.020 ac Runoff coeff. = 0.35* Intensity = 7.011 in/hr Tc by User = 10.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 Composite(Area/C)=[(0.230 x 0.25)+(0.600 x 0.30)+(0.070 x 0.90)]/1.020 PRE AREA 4 Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 — 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 — Hyd No. 4 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 9 POST AREA 4 Hydrograph type = Mod. Rational Peak discharge = 3.843 cfs Storm frequency = 100 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 1,153 cuft Drainage area = 1.020 ac Runoff coeff. = 0.43* Intensity = 8.762 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 1.0 x Tc Target Q = 0.000 cfs Est. Req'd Storage= 0 cuft *Composite(Area/C)_[(0.480 x 0.35)+(0.150 x 0.90)+(0.270 x 0.25)]/1.020 POST AREA 4 Q (cfs) Hyd. No. 9 -- 100 Year Q (cfs) 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 --�- Hyd No. 9 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 14 Area 4 Routed Hydrograph type = Reservoir Peak discharge = 2.023 cfs Storm frequency = 100 yrs Time to peak = 0.12 hrs Time interval = 1 min Hyd. volume = 666 cuft Inflow hyd. No. = 9 - POST AREA 4 Max. Elevation = 633.96 ft Reservoir name = Area 4 Biofilter Max. Storage = 772 cuft Storage Indication method used. Exfiltration extracted from Outflow. Area 4 Routed Q (cfs) Q (cfs Hyd. No. 14-- 100 Year ) 4.00 4.00 3.00 3.00 S S 2.00 --- 2.00 1.00 -- 1.00 0.00 .._ 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 0.5 Time (hrs) Hyd No. 14 Hyd No. 9 Total storage used = 772 cuft Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 5 PRE AREA 5 Hydrograph type = Rational Peak discharge = 2.192 cfs Storm frequency = 100 yrs Time to peak = 0.22 hrs Time interval = 1 min Hyd. volume = 1,710 cuft Drainage area = 0.960 ac Runoff coeff. = 0.36 Intensity = 6.342 in/hr Tc by User = 13.00 min IDF Curve = Albermarle.idf Asc/Rec limb fact = 1/1 PRE AREA 5 Q (cfs) Hyd. No. 5-- 100 Year Q (cfs) 3.00 3.00 2.00 2.00 1.00 1 1.00 0.00 - 0.00 0.0 0.0 0.1 0.1 0.1 0.2 0.2 0.2 0.3 0.3 0.3 0.4 0.4 0.4 Hyd No. 5 Time (hrs) Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 10 POST AREA 5 Hydrograph type = Mod. Rational Peak discharge = 4.122 cfs Storm frequency = 100 yrs Time to peak = 0.08 hrs Time interval = 1 min Hyd. volume = 1,237 cuft Drainage area = 0.960 ac Runoff coeff. = 0.49 Intensity = 8.762 in/hr Tc by User = 5.00 min IDF Curve = Albermarle.idf Storm duration = 1.0 x Tc Target Q = 0.000 cfs Est. Req'd Storage= 0 cuft POST AREA 5 Q (cfs) Q cfs Hyd. No. 10 -- 100 Year ( ) 5.00 5.00 4.00 4.00 3.00 3.00 a a 2.00 2.00 1.00 1.00 a 0.00 0.00 0.0 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.2 a Hyd No. 10 Time (hrs) a Hydrograph Report Hydraflow Hydrographs by Intelisolve v9.23 Thursday,Apr 17,2008 Hyd. No. 15 Area 5 Routed Hydrograph type = Reservoir Peak discharge = 0.180 cfs Storm frequency = 100 yrs Time to peak = 0.17 hrs Time interval = 1 min Hyd. volume = 270 cuft Inflow hyd. No. = 10 - POST AREA 5 Max. Elevation = 644.65 ft Reservoir name = Area 5 Biofilter Max. Storage = 1,214 cuft Storage Indication method used. Area 5 Routed Q (cfs) Hyd. No. 15-- 100 Year Q (cfs) 5.00 5.00 4.00 4.00 3.00 -- 3.00 2.00 -- 2.00 1.00 ------ 1.00 0.00 -= ' 0.00 0.0 0.3 0.7 1.0 1.3 1.7 2.0 2.3 2.7 3.0 Time (hrs) Hyd No. 15 Hyd No. 10 Total storage used = 1,214 cuft Blue Ridge Cohousing Weir Flow Calculations for Biofilters 1 to 5 Weir Report Hydraflow Express by Intelisolve Thursday,Apr 24 2008 Biofilter 1 V-Notch Weir Highlighted Crest = Sharp Depth (ft) = 0.32 Angle (Deg) = 90 Q (cfs) = 0.190 Total Depth (ft) = 1.50 Area (sqft) = 0.10 Velocity (ft/s) = 1.88 Calculations Top Width (ft) = 0.64 Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 0.19 Depth (ft) Biofilter 1 Depth (ft) 2.00 2.00 1.50 1.50 1.00 1.00 0.50 0.50 0.00 0.00 -0.50 -0.50 0 1 2 3 4 5 6 7 8 Weir W.S. Length (ft) Weir Report Hydraflow Express by Intelisolve Thursday,Apr 24 2008 Biofilter 2 V-Notch Weir Highlighted Crest = Sharp Depth (ft) = 0.30 Angle (Deg) = 90 Q (cfs) = 0.160 Total Depth (ft) = 1.50 Area (sqft) = 0.09 Velocity (ft/s) = 1.81 Calculations Top Width (ft) = 0.59 Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 0.16 Depth (ft) Biofilter 2 Depth (ft) 2.00 2.00 1.50 - 1.50 1.00 1.00 0.50 0.50 0.00 0.00 -0.50 — — -0.50 0 1 2 3 4 5 6 7 8 Weir W.S. Length (ft) Weir Report Hydraflow Express by Intelisolve Thursday,Apr 24 2008 Biofilter 3 V-Notch Weir Highlighted Crest = Sharp Depth (ft) = 0.82 Angle (Deg) = 90 Q (cfs) = 2.020 Total Depth (ft) = 1.50 Area (sqft) = 0.67 Velocity (ft/s) = 3.01 Calculations Top Width (ft) = 1.64 Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 2.02 Depth (ft) Biofilter 3 Depth (ft) 2.00 2.00 1.50 1.50 1.00 1.00 v 0.50 0.50 0.00 0.00 -0.50 — -0.50 0 1 2 3 4 5 6 7 8 Weir W.S. Length (ft) Weir Report Hydraflow Express by Intelisolve Thursday,Apr 24 2008 Biofilter 4 V-Notch Weir Highlighted Crest = Sharp Depth (ft) = 0.82 Angle (Deg) = 90 Q (cfs) = 2.020 Total Depth (ft) = 1.50 Area (sqft) = 0.67 Velocity (ft/s) = 3.01 Calculations Top Width (ft) = 1.64 Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 2.02 Depth (ft) Biofilter 4 Depth (ft) 2.00 2.00 1.50 - 1.50 1.00 1.00 0.50 0.50 0.00 0.00 -0.50 — - - 1— -0.50 0 1 2 3 4 5 6 7 8 Weir W.S. Length (ft) Weir Report Hydraflow Express by Intelisolve Thursday,Apr 24 2008 Biofilter 5 V-Notch Weir Highlighted Crest = Sharp Depth (ft) = 0.31 Angle (Deg) = 90 Q (cfs) = 0.180 Total Depth (ft) = 1.50 Area (sqft) = 0.10 Velocity (ft/s) = 1.86 Calculations Top Width (ft) = 0.62 - Weir Coeff. Cw = 3.33 Compute by: Known Q Known Q (cfs) = 0.18 Depth (ft) Biofilter 5 Depth (ft) 2.00 2.00 1.50 1.50 a 1.00 1.00 0.50 0.50 0.00 0.00 -0.50 • — -0.50 0 1 2 3 4 5 6 7 8 Weir W.S. Length (ft) Blue Ridge Cohousing Channel Calculations for Area 1 Channel Report Hydraflow Express by Intelisolve Thursday,Apr 17 2008 a <Name> Triangular Highlighted Side Slopes (z:1) = 1.00, 1.00 Depth (ft) = 0.57 Total Depth (ft) = 1.00 Q (cfs) = 1.100 Area (sqft) = 0.32 Invert Elev (ft) = 629.00 Velocity (ft/s) = 3.39 Slope (%) = 4.30 Wetted Perim (ft) = 1.61 N-Value = 0.030 Crit Depth, Yc (ft) = 0.60 Top Width (ft) = 1.14 Calculations EGL (ft) = 0.75 ss- Compute by: Known Q Known Q (cfs) = 1.10 Elev (ft) Depth p (ft) Section 631.00 2.00 630.50 1.50 a 630.00 • 1.00 . v 629.50 -� 0.50 629.00 0.00 628.50 -0.50 0 .5 1 1.5 2 2.5 3 Reach (ft) Channel Report Hydraflow Express by Intelisolve Thursday,Apr 17 2008 <Name> Triangular Highlighted Side Slopes (z:1) = 1.00, 1.00 Depth (ft) = 0.52 Total Depth (ft) = 1.00 Q (cfs) = 1.100 Area (sqft) = 0.27 Invert Elev (ft) = 629.00 Velocity (ft/s) = 4.07 Slope (%) = 6.50 Wetted Perim (ft) = 1.47 N-Value = 0.030 Crit Depth, Yc (ft) = 0.60 Top Width (ft) = 1.04 Calculations EGL (ft) = 0.78 Compute by: Known Q Known Q (cfs) = 1.10 Elev (ft) Section Depth (ft) 631.00 2.00 Mst 630.50 1.50 630.00 - 1.00 9000. v 629.50 0.50 629.00 0.00 a 628.50 -0.50 0 .5 1 1.5 2 2.5 3 Reach (ft) Blue Ridge Cohousing Yard Inlet Calculations for Area 1 Blue Ridge CoHousing JN: 1770.0 Yard Inlet BY: BLM DATE: 04/16/08 Drainage Area Area (ac.) C Area*C Comments 0.00 0.80 0.00 Gravel 0.13 0.90 0.12 Impervious 0.08 0.30 0.02 Dev Grass 0.04 0.25 0.01 Woods Total Area 0.25 acres Weighted C 0.60 Area*C 0.15 Time of Concentration tOverland 6.74 L= 51' H= 1.3 C'= 0.35 tChannel 0.52 L= 82' H= 10' tc 7.00 min Intensity 1=B/(tc+D)^E Storm Frequency B D E 12 4.69 in/hr 2 49.02 10.50 0.82 110 6.07 in/hr 10 46.95 9.50 0.73 110o 7.93 in/hr 100 31.09 5.00 0.55 Results Q2 0.70 cfs 010 0.91 cfs Q100 1.49 cfs Q = C*l*A - 01 kr1 ed, — . kL 4) , . IT i•1 J - Y NEMINININIUNIMMINI ! . <1 ANIMINNEUIMMUMNIMMI • - Li gi. BE111111111111111111111111111 IV: on g 1111111sui MINI cr J 0 '_1 .k.• 1111111111 2 u, 6-x. zill111111111111E Mall fa.o t :i : I z ES i,-; : ,: 0 .... s: cid io 1111111111111111111111111111111: 1111111111111111111111111111111111111I . iiy: alummunammuniumunt ,.t. sl irignimiiiiiiiiiiiiiiiiiii ui 1.... 43. ,1, 02 z z4.4 t, , - 5 -11111111111111111111111 .fi' ._ „Q .. 2 .ii. ..! ligind10111111111161111111111 , . u. .. ,.,.. , ,, , ' -' - , 1 . , • . . , • , . ,, • , , • .. , 1 , , ..„ . .., • , •• . _ . . .. . 4—72 .,•-..4 Response to Albemarle County staff comments on the proposed Bio-filter locations Staff has expressed concerns over the proximity of the five proposed bio-filters to the site residences. Traditional stormwater management facilities are generally located away from residences for the following reasons: • To limit public access for safety reasons due to the potential for high stormwater flows and/or standing water depths. • The general lack of aesthetic appeal of traditional stormwater facilities. • To clearly delineate the stormwater facilities to assure access by maintenance personnel. • To limit the potential for disease vectors associated with standing water(e.g. es. mosquitoes). In response to these concerns we offer the following comments and note changes to the r bio-filter designs. Attached are photographs of bio-filters located on sites in Blacksburg, Virginia. • Five bio-filters are used to divide the project area into 1.08 acre or less drainage •r areas to minimize the size of the facilities and the quantity of stormwater flowing through any single facility. The riser/outlet pipe structures were replaced with a weir outlet. This simplified design eliminates large piping structures near the WNW residences and the safety concerns associated with these structures. The 100-yr flow depths over the outlet weirs range from 1-6 inches and velocities range from 0.5-5.2 feet per second. The 2-yr design storm water ponding depths range from 0.2"-3" inches. The bio-filter are designed to drain within 24-hours. • Situating bio-filters near residences has a positive effect the landscape. The bio- filter plantings adds aesthetically pleasing diversity to a development landscape. • The site plan concept has no private lawn areas that would limit access. All outside areas are common areas. Signs will be posted around the bio-filters to both explain their function and delineate their boundaries. Eliminating the outlet structures reduces the potential maintenance requirements. • The bio-filter 24-hour drawdown time will not provide favorable conditions for disease vectors. . '-`' ' ' 'I';, ' .,,,."':..4‘4. i 41:ifilh aa • ak d li x "" Lee and Prospect Street Site, Blacksburg, VA. Dividing the drainage area among several bio-filters, the lack of outlet risers and discharge piping and the shallow design of biofilters eliminate the safet concerns associated with traditional stormwater structures. . '-‘,.--- .-,Tt! i'.. .',* :'5,k . - ,'.,, - ‘0. :;:kf.,„ % . ,,,./. .,' Ili 4 • , +d , .. ik pi .4 ; " u s r ;,§x " _ ,_ € ,. 01"1 ',,' 1.'''''1:;71 ifi m i. x 41116 Woolwine Street, Blacksburg, VA. The bio-filter plantings adds diversity to a development landscape. f : 'N111100,,,,,,,, , $ ip LTJ ' 1 ++3 ,i il , , ,, ' _ ,,''',,,,,„ '1,:i -7,-'-r l'7,..1,9- A,..,,,3' , ti iiiY Lee and Prospect Street Site, Blacksburg, VA. Situating bio-filters in common areas allow for maintenance access despite the proximity to residences. a..