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HomeMy WebLinkAboutWPO201500025 Calculations 2015-08-20 COLONIAL AUTOMOTIVE CENTER STORMWATER MANAGEMENT CALCULATION PACKET Date of Calculations April 8, 2015 PREPARED BY: 1:,3gCOLLINS E S IN N 200 GARRETT STREET, SUITE K CHARLOTTESVILLE,VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com SCS Method Calculations Soils Map (Source: NRCS Web Soil Survey Online Database) / NZ* I t$!*'4'..4,,,!4*: . , , ' :‘* . •* ,,,*1'. 4‘ ji ** % 't* ;.,*,./Al....?:.*:$.'., . *..*:..!:.• .;••*.-*..'''' :. - , i ' :,. • yf A. ,,,,. .,-,,,.,,,,,,;,.....,,*,...s....+. . ,.........,i,,,,..„ ,,:z,.:.,,,,..,,,,,,,t,:i.. -.,;,..,i,:i.,., ,,,,,,,,,,,:,..,.,, ,,, ,,:,,,,„, . i s.ki k.* t I. . .4 ••• .41,1,.„„ .7 If .. f ao...... V , 4' • . '• Xe I \ * % •,st \ ,„ ,.) ,,,41,, .**......._,•1".11 4tit, , "' ...-, , woo. *-Iltive* Ai, ., . t ' - , • ,.. 11,!111100t. .,, r 4.. k ** • • \ i 7, , ' i . , . eV . Soils Table (Source: NRCS Web Soil Survey Online Database) Map Unit t egend Albemarle County,Virginia(VA003) Map Unit Map Unit Name Percent Symbol of AOI 278 Elioak loam,2 to 7 44.0% percent slopes 27C Elloak loam,7 to 15 48.1% percent slopes 39C Hazel loam,7 to 15 7.8% percent slopes Totals for Area of Interest 100.0% Note: Soils' are predominantly composed of hydrologic soil type B. U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 2:Runoff Curve Number and Runoff Project: CMA Properties Designed By: FGM,PE Date: 4/8/2015 Location: Berkmar Drive Checked By: FGM,PE Date: 4/8/2015 Check One: Present X De X 1.Runoff curve Number(CN) Cover description Soil name and CN(weighted)= Drainage Area (Cover type,treatment,and hydrologic condition; Area Product of Calculated hydrologic group CN total product/ Description percent impervious;unconnected/connected (Acres) CN x Area 'S'Value (Appendix A) total area impervious area ratio) A Impervious Areas 98 0.50 49.0 B Woods in Good Condition 55 0.00 0.0 66.7 5.00 (Present) Lawns in Good Condition(75%+Groundcover) 61 2.77 169.0 A Impervious Areas 98 0.94 92.1 (Phase I) B Woods in Good Condition 55 0.00 0.0 71.6 3.96 Lawns in Good Condition(75%+Groundcover) 61 2.33 142.1 A Impervious Areas 98 2.44 239.1 (Phases I+II) D Woods in Good Condition 55 0.00 0.0 88.6 1.29 Lawns in Good Condition(75%+Groundcover) 61 0,83 50.6 2.Runoff 1-Year Storm 2-Year Storm 10-Year Storm Drainage Area Description Frequency-years 1 2 10 n/a Rainfall,P(24 hour)-inches 3.5 3.7 5.6 n/a Runoff,Q-inches 0.83 0.95 2.20 A (Present) Runoff,Q-inches 1.10 1.23 2.64 A(Phase I) Runoff,Q-inches 2.32 2.51 4.31 A(Phases I+II) U.S.Department of Agriculture FL-ENG-21A Natural Resources Conservation Service 06/04 TR 55 Worksheet 3:Time of Concentration(T ,)or Travel Time(T,) Project: CMA Properties Designed By: FGM,PE Date: 4/8/2015 Location: Berkmar Drive Checked By: FGM,PE Date: 4/8/2015 Check One: Present X Developed X Check One: T, X T, Through subarea n/a A A A Segment ID: (Present) (Phase I) (Phases I+II) Sheet Flow:(Applicable to T ,only) Woods-Light Woods-Light Woods-Light 1 Surface description(Table 3-1) Underbrush Underbrush Underbrush 2 Manning's roughness coeff.,n(Table 3-1 0,4 0.4 0.4 3 Flow length,L(total L <100)(ft) 100 100 100 4 Two-year 24-hour rainfall,P,(in.) 3.7 3.7 3.7 5 Land slope,s(ft/ft) 0.06 0.06 0.06 6 Compute T,=[0.007(n"L)08]/ u.5 sp6 I 0.214 I 0.214 I 0.214 Shallow Concentrated Flow: 7 Surface description(paved or unpaved) Unpaved Unpaved 8 Flow Length,L(ft) 590 190 9 Watercourse slope,s(ft/ft) 0.06 0.03 10 Average velocity,V(Figure 3-1)(ft/s) 4 2.8 11 T,=L/3600.V I 0.041 I 0.019 I I I I I I 1 I I Channel Flow: 12 Cross sectional flow area,a(ft 2) > o „ u E .- 13 Wetted perimeter,P„(ft) „ E „ . c A o 14 Hydraulic radius,r=a/P.(ft) EE o.. —oe' „ o I;15 Channel Slope, o °s(ft/ft) �� v 16 Manning's Roughness Coeff,n `o ,, 9 L Si o 17V=[1.49r515s°s]/n o 3 n 18 Flow length,L(ft) < ° < 'a° 19 T,=L/3600•V I I 0.011 I 0.022 I I I I I I I 20 Watershed or subarea T,or T, (Add T,in steps 6,11 and 19) 0.255 I 0.244 I 0.237 I I I I I F l0 00 V PD In A W N S -o 7] _-I• 23 0 I-+ n 1- 2 C p N O C C n 7 A T ° O 7 7 �. • O CD On `O N VI o a p p n o CD x a. o " ti = _a 00 a a O --wn 0) y^ A- O y 0 a ° ▪ m c D D, CD o o_ a n c C = z o II• n p- A 7r p 7 CU .' m m co v z 3 O 0, V, -a 0_ N N< 7" 0, CCD 7 d 3 p 0 3 S v .^, A d ,D _1. 3 D m p 3 n K A ro 0 o c ° o ° °: 3 > o A m , ° m ro '.. o 7 3 v n -.' v Q o p a N N < 7 x d o D n �° n 0 7 7 Crci <n K. = A 7 n, a II II n Z CND C. Tic NK ? D II 0) II N O rD . O, 7I =• N 3 N v' O_ IIN N O C = d = O n n 7 m m O• rSD O. Z ,n n T p ° X N.1 o !'' COP w V N w 0 O - ~ 0 0 - 0, W p O., O iO-- OO -7H 0, - 0M (-71I" I-' l0 LnN WN O = O0H D . 0A .A LnO V OV • C O Ol V In K coa. O V NV 0 I-+ 7 7 rD 77 <n Co I-' N O N O O 0, co 00 O 0 00 S 01 'o O ? VI O Psi N 1--< VVi▪ ON • ut ~ 0 CI • O O w N 0 ro n • aI- V O O W O V •O w (.7 7' 7" n S N W 00 N V N O - A Ol N D aon s. I-' _ '▪ D -0 • c o v m o N O 0, OL V VI 77 0) S A V1 iv A N Ql O p n O = !`, V O W v cn• 0 N 0 O V Ur . so a; p 0 m p v • d. N V O O w O 00 O N n y :-11.7. • p S i-. O O V V N O = A CC.._l lOil D .o p nw▪ 0 1"' + p D 0_ ,< cm A v p O 7 rD 7' F-' WCn O N VI 1_' 0, ,, 0 VI v en 0 0 O o, n 0 M _ nrD '^ o ala d n 00 73 cD1r 7 o• D Cl).aa. 7 N O CO 0, < < 0 T T pv d c) c) n K 7 . 00 o -o v a rD m m p' D 7 ro a 0 0 o0, 0, c Oco , rD CD T I- n o m N00 00 Z _ O GI O▪ D 0 0 I:., 7 (o O) U, � A n Water Quality Calculations (For Phase I, and Phases I + II) Virginia Runoff Reduction Method ReDevelopment Worksheet-v2.8-June 2014 , To be used w/2011 BMP Standards and Specifications I Site Data -,--- [ ...._._.. _.___..._ 1 . Project Name:CMA-Phase I of the Development I . Date:4/6/15 I . . . .• data input cells I . ,•„,.,„ -, :',2i.'"?,€,?„,..Z,„ 'i€,V.ik,•;,,,:‘,•calculation cells 1 , • . • • . • constant values i . € • 1 I _ • • Post-ReDevelopment Project&Land Cover Information Total Disturbed Acreage -BIB 1 - , I'• • I , _ 010,0i,' Constants ; Annual Rainfall(inches) 43 Tir-g--affilaitlif-&-eiii-(in-citei)- 1.00 , 1,86 i Phosphorus EMC(mg/L) 0.26 Nitrogen EMC(mg/L) .• Target Phosphorus Target Load(Ib/acre/yr) 0.41 Pi 0.90 i I Ii 1 irl Pre-ReDevelopment Land Cover(acres) I A soils IB Soils C Soils D Soils Totals ; ; i f Forest/Open Space(acres)-undisturbed, ,z1*„liZ''''',7,-,: V•,,1/41 ke i „ ••, protected forest/open space or reforested land P-00' -:€....., 000 . 000 •000 'Vii3O.090- Managed Turf(acres)-disturbed,graded for f1/4 . , 4 ....- ' . ' -., „ ,-.. 1 yards or other turf to be mowed/managed 000 094 ,.„,..i.i,,i 0,00 ' -.000 .', 33t i-€.1•ii, I Impervious Cover(acres) 000 i-, , ., 1(2,4--I. ik, 00 0.00 Total ti: 04-•:4,I, : I . Post-ReDevelopment Land Cover(acres) , • I A soils ,1111 Soils , C Soils D Soils Totals •• ; . , Forest/Open Space(acres)-undisturbed, , , , • .,• i,: protected forest/open space or reforested land 000• 0.22 tt,.. , 040 ' 0.00 ' Ili —', ,, 1 Managed Turf(acres)-disturbed,graded for • _ " . '(..' '' '•''':','`)9 :-,, ' yards or other turf to be mowed/managed , opct ., _m 4( ' !,- 0.00 ., z • .,' ,,•:, :14,,,, ,4, 1\„.'•'- Impervious Cover(acres) 009 • '-r Total Area Check Okay i Okay Okay Okay Rv Coefficients I . A soils B Soils C Soils D Soils Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 _ 095 0.95 0.95 , Land Cover Summary Listed Adjusted' Land Cover Summary Land Cover Summary Pre-ReDevelopment Ij Post-ReDevelopment I Post-ReDevelopment New Impervious Forest/Open Spacer-,.,r.,:'7.:,,, Forest/Open Space Cover(acres) ''• '"",i'i••042`;`,'.141°•i'df.:.;,.9.(.., ., ,,... Cover(acres) • ...:4„,„, ( y,( , • - ...-•-,‘.6€f1.4,41 ',' ,.,.;,. ,, . Compositei.i•-i, f • Composite Rv(forest) ' ,,,,, :.,0(..-1'' .i•••4 Rv(forest) •, fi ,• '',5',:;V:-.• €:i %Forest %Forest . '•.,.'', •'''',', ;1;?,:i,,,,,,, i, Managed Turf ,, ,,,, ,.,:„.A.,€„( Managed Turf Cover(acres) • Cover(acres) ,..,,,• .-',...,,,',1 i,: ',*, Composite Rv(turf) •• • ,-.,„:. r. , Composite Rv(turf) i P. %Managed Turf 5/Managed Turf ".",,• -. -,Lfr.:,4 .'14,:77:, ReDev Impervious . . ,..-. Impervious Cover(acres) Cover(acres) New Impervious Cover(acres) •' i•i.,'0,49 Rv(impervious) Rv(impervious) '''''' t-- RvOmpervious) .i. 5/Impervious %Impervious %Impervious ' ,,,,- Total ReDev.Site „r• ",, ,,,;4€.• Total Site Area(acres) •' ',i,:e' . - o ? ,t1- ''' Area(acres) I Total New Dee.Site Area(acres) II"'I''I"I,C 0.4 "•:Iir'I Site Rv ,';.”I' °P40,,'"- ReDev.Site Rv ,.., -• ,,, i 4.] New Dev.Site Rv ,4, Post- ,-,4:','$',,,.`• :1,''' •• ',>*•'' • ReDevelopment . 4,,, -•:;^-;,,,;, r';.;i..,,• ;:vr Treatment Volume ' .V.j., '' Post-Development Treatment Pre-Development Treatment Volume(acre-ft) ..:`;',,,'.:".'„ 1,,i*'-'. ' '''..t .,'," (acre-ft) Volume(acre-ft) ''• -11-45404 , i . Post- ,-..„.,ii• • .1,,, i•-,...WW.-••• ReDevelopment ,, •„€:-..,&ii'.....,,,,_:€:••€ii.,J;:-.5... . Pre-Development Treatment Volume(cubic ,,-, .;.",,,,,,,S.--, ,,-, ,,,t,,..: Treatment Volume .:€.;.'•; ',1: • Post-Development Treatment,, ,, .,, •,( feet) :, • : '''A 7 131 ..*,,,.' 4, - fcubic feet) Volume(cubic feet) i",, i • 4-€1/(i/ 1-iost- € 4 ,,,II*,,,,A•• ...;;III.ifrI,I:,I"'4." „. ,I,Pki, ;,,,I'f''',•II"''''''I'".;n",'I' " ReDevelopment ,,-(•. .,- •••• „ Pre-Development Load(TP)(lb/yr) r:', ' ''''VY,t1,44tti''t,..,'' '' -.: Load(TP)(Ib/yo ' ----...•..i4.1• Post-Development Load(TP)(lb/yr) • ' '".€ .,'MRS r I i k 'Adjusted Land Cover Summary reflects the pre redevelopment Maximum%Reduction Required Below:"i'-', . land cover minus the pervious land cover(forest/open space or Pre-ReDevelopment Load• , ',, 4 managed turf)acreage proposed for new impervious cover.The i • , adjusted total acreage is consistent with the Post Redevelopment TP Load Reduction Required for.: ,'- "''4 .I., ' Load Reduction Required for acreage(minus the acreage of new impervious cover).The load Redeveloped Area(Ib/yr). . ,.44 TP- New Impervious Area(lbryr) " I.% '", I"0116 reduction requnement for the new Impervious cover to meet the new 1 • development load limit is computed in Column I. 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Phosphorous TOTAL PHOSPHOROUS LOAD REDUCTION REQUIRED(LB/YEAR)L',a RUNOFF REDUCTION(cf)� ' PHOSPHOROUS LOAD REDUCTION ACHIEVED(LB/YR)' ,, ' ADJUSTED POST-DEVELOPMENT PHOSPHOROUS LOAD(TP)(Ib/yr)(' REMAINING PHOSPHOROUS LOAD REDUCTION(LB/YR)NEEDEDiCONGRATULATIONSII YOU EXCEEDED THE TARGET REDUCTION BY 1.1 LB/YEAR,' 1 S t4 Nitrogen(for information purposes) RUNOFF REDUCTION(ct) NITROGEN LOAD REDUCTION ACHIEVED(LB/YR) ,, tx:,v." ADJUSTED POST-DEVELOPMENT NITROGEN LOAD(TP)(Ib/yr) Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method ReDevelopment Worksheet-v2.8-June 2014 Site Data Summary Total Rainfall=43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.22 0.00 0.00 0.22 4.25 Turf(acres) 0.00 3.23 0.00 0.00 3.23 62.36 Impervious(acres) 0.00 1.73 0.00 0.00 1.73 33.40 5.18 100.00 Site Rv 0.44 Post Development Treatment Volume(ft') 8335 Post Development TP Load(Ib/yr) 5.24 Post Development TN Load(Ib/yr) 37.46 Total TP Load Reduction Required(Ib/yr) 1.63 Total Runoff Volume Reduction(ft') 3819 Total TP Load Reduction Achieved(Ib/yr) 3 Total TN Load Reduction Achieved(Ib/yr) 19.72 Adjusted Post Development TP Load(Ib/yr) 2.54 Remaining Phosphorous Load Reduction(Lb/yr)Required 0.00 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.22 0.00 0.00 0.00 0.00 0.22 Turf(acres) 2.11 0.00 0.00 0.00 0.00 2.11 Impervious(acres) 0.94 0.00 0.00 0.00 0.00 0.94 3.27 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(Ib/yr) 2.70 0.00 0.00 0.00 0.00 2.70 TN Load Red.(lb/yr) 19.72 0.00 0.00 0.00 0.00 19.72 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area A Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.22 0.00 0.00 0.22 6.73 Turf(acres) 0.00 2.11 0.00 0.00 2.11 64.53 Impervious(acres) 0.00 0.94 0.00 0.00 0.94 28.75 3.27 BMP Selections Practice Credit Area(acres) Downstream Practice 6.b.Bioretention#2(Spec#9) Impervious: 0.94 None Turf(Pervious): 2.11 None Total Impervious Cover Treated(acres) 0.94 Total Turf Area Treated(acres) 2.11 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 2.70 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 19.72 Summary Print Virginia Runoff Reduction Method ReDevelopment Worksheet-v2.8-June 2014 To be used w/2011 ard Specifications — — — — Site Data - —— --0000.. ---- Project Name:CMA-Final Buildout I Date:4/6/15 ' ' 1 (data Input cells • ,'`= '' , , ;,c •,' • -calculation cells constant values 1 Post-ReDevelopment Project&Land Cover Information Total Disturbed Acreage 5016 Constants 1 •i Annual Rainfall(inches) 4$ ' Target E__....__(nches) - 000__0. _ __ _.._____ __...__—_—_._. Target Rainfall Event(inches) 1.00 ----- Phosphorus EMC(mg/L) 0.26 Nitrogen EMC(mg/L) 1.86 Target Phosphorus Target Load(Ib/acre/yr) 0.41 i Pj 0.90 Pre-ReDevelopment Land Cover(acres) i : A soils 1E4 Soils C Soils D Soils Totals i Forest/Open Space(acres)-undisturbed, "'?.:;:, - • protected forest/open space or reforested land 0.00 tj (#,� #t - ;O,t#!'• Managed Turf(acres)-disturbed,graded for t "' yards or other turf to be mowed/managed 00 _ - ,g4 - jj��.. r jrs,;; Impervious Cover(acres) . W..W 1.24 0,00 d,00 �. - .• ''.-4 Total , Post-ReDevelopment Land Cover(acres) I A soils JB Soils C Soils D Soils Totals Forest/Open Space(acres)-undisturbed, _ - ` e protected foresVopen space or reforested land 0-06 0,720,72000 '0.00 _OA• , Managed Turf(acres)-disturbed,graded for _ _ - - yards or other turf to be mowed/managed 0.00 1, - - ,-,•.4.7.0,‘',' Impervious Cover(acres) 1/00 � ' (�Q0 011ifw 'Total ; ,'g.. "I Area Check Okay 1 Okay Okay Okay Rv Coefficients I I A soils B Soils C Soils D Soils Forest/Open Space 0.02 0.03 0.04 0.05 Managed Turf 0.15 0.20 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 I Land Cover Summary Listed ;Adjusted' Land Cover Summary f Land Cover Summary Pre-ReDevelopment Post-ReDevelopment Post-ReDevelopment New Impervious Forest/Open Space.),--,-Forest/Open Space Cover(acres) j$Q Cover(acres) �,.;-;r` Composite Composite Rv(forest) s• Rv(forest) %Forest _ • %Forest '' a> ($& Managed Turf Cover(acres) ,, Managed Turf acres 3.94"°'✓V'y, `';aa Cover(acres) Composite Rv(turf) Composde Rv(turf) %Managed Turf '" '"/Managed Turf ReDev Impervious Impervious Cover(acres) Cover(acres) . • 1.24 New Impervious Cover(acres) '14 Rv(impervious) • ' ,'p 0." Rv(impervious) Rv(impervious) - 0-98 %Impervious Ija4$k ,r;; •,' ' %Impervious -- %impervious '10161, Total ReDev.Site .,,.a., ; Total Site Area(acres) t tt. $, '7 • 1Area acres ' Site Rv - ? ( ) 18 • Total New Dev.Site Area(acres)< 1,90 `- ' 0 ReDev.Site Rv .,440 New Dev.Site Rv - ' zott Post- ,., .•r'i „r. r�:` • .• .,;'1'e.:, '-jr.,,,,. --‘ ✓;,4 ReDevelopment ., y Treatment Volume ., Post-Development Treatment ' Pm-Development Treatment Volume(acre-ft) •'0- , .. `vl'�.1 (acre-ft) .."c Al Volume(acre-ft) ��.#LtSlS Post- '43;, ReDevelopment Pre-Development Treatment Volume(cubic •'"' Treatment Volume Post-Development Treatment ` ' feet) ^s.7, ,-• $'�� (cubic feet) •' ,.- Siler Volume(cubic feet) -- • ':$601 .,-S:,e'r- ,.i Hc•i:r,;,,'t t.1), Post- ReDevelopment . .., Pre-Development Load(TP)(Ib/yr) "'acv. '•_ 445 „ , ":9 ,. Load(TP)(lb/yr) {' y'1''''''"'(,',#.,4011 Post-Development Load(TP))lb/yr) .. 33 'Adjusted Land Cover Summary reflects the pre redevelopment ! Maximum%Reduction Required Below-', , •• land cover minus the pervious land cover(foresVopen space or Pre-ReDevelopment Load- - managed turf)acreage proposed for new impervious cover.The 1 : a`% adjusted total acreage is consistent with the Post Redevelopment TP Load Reduction Required fors •'.'l TP Load Reduction Required for acreage(minus the acreage of new impervious cover).The load Redeveloped Area(Ib/yr) Q, New Impervious Area(Ib/yr) I. 3.56/ reduction requnement for the new impervious cover to meet the new I development load limit is computed in Column I. Total Load Reduction Required _ (Ib/yr) 4, Pre-Development Load(I N)(lb/yr) ;.'44-01Post-Development Load(TN)(Ib/yr) - . """"" Onlnye Aw.A . ,?IOINR INIIIS'1"iA1111.R 014EA V7.:MEp'i..[.TMk NNNT;ANP4 rr.d NWIMq'f'...i? 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Y:w;' . t. a�.t.on �� ,LASEN u unury coMVLInxEEtAB roam EEognuAxc uL<ouigNs. xlfnoaw F€i6vuer rxn2mUL13fA! Illlp(T.l,1NC Site Results D.A.A D.A.B D.A.C D.A.D D.A.E AREA CHECK OK."' .. IMPERVIOUS COVER TREATED ^;" �,"4 ' _, ;.' 7OK. TURF AREA,. ,, �, -• ' OK �dUB TURF AREA TREATED z,% _�,, r .'I ; .'���. OK. AREA CHECK K.OOK. OK. OK. OK. Phosphorous TOTAL PHOSPHOROUS LOAD REDUCTION REQUIRED(LB/YEAR)I . '^;;',;/{t RUNOFF REDUCTION(d)'.. • , PHOSPHOROUS LOAD REDUCTION ACHIEVED(LB/YR)• •, . ADJUSTED POST-DEVELOPMENT PHOSPHOROUS LOAD(TP)(Ib/yr)i '"', REMAINING PHOSPHOROUS LOAD REDUCTION(LB/YR)NEEDED CONGRATULATIONSII YOU EXCEEDED THE TARGET REDUCTION BY 0.9 LB/YEAR Nitrogen(for information purposes) RUNOFF REDUCTION(cf),. •s., NITROGEN LOAD REDUCTION ACHIEVED(LB/YR))) ADJUSTED POST-DEVELOPMENT NITROGEN LOAD(TP)(Ib/yr) . b'i Virginia Runoff Reduction Method Worksheet Virginia Runoff Reduction Method ReDevelopment Worksheet-v2.8-.June 2014 Site Data Summary Total Rainfall=43 inches Site Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.22 0.00 0.00 0.22 4.25 Turf(acres) 0.00 1.73 0.00 0.00 1.73 33.40 Impervious(acres) 0.00 3.23 0.00 0.00 3.23 62.36 5.18 100.00 Site Rv 0.66 Post Development Treatment Volume(ft') 12419 Post Development TP Load(Ib/yr) 7.80 Post Development TN Load(Ib/yr) 55.82 Total TP Load Reduction Required(Ib/yr) 4.13 Total Runoff Volume Reduction(ft') 7086 Total TP Load Reduction Achieved(Ib/yr) S Total TN Load Reduction Achieved(Ib/yr) 36.58 Adjusted Post Development TP Load(Ib/yr) 2.80 Remaining Phosphorous Load Reduction(Lb/yr)Required 0,00 Drainage Area Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total Forest(acres) 0.22 0.00 0.00 0.00 0.00 0.22 Turf(acres) 0.61 0.00 0.00 0.00 0.00 0.61 Impervious(acres) 2.44 0.00 0.00 0.00 0.00 2.44 3.27 Drainage Area Compliance Summary D.A.A D.A.B D.A.C D.A.D D.A.E Total TP Load Red.(Ib/yr) 5.00 0.00 0.00 0.00 0.00 5.00 TN Load Red.(Ib/yr) 36.58 0.00 0.00 0.00 0.00 36.58 Summary Print Virginia Runoff Reduction Method Worksheet Drainage Area A Summary Land Cover Summary A Soils B Soils C Soils D Soils Total %of Total Forest(acres) 0.00 0.22 0.00 0.00 0.22 6.73 Turf(acres) 0.00 0.61 0.00 0.00 0.61 18.65 Impervious(acres) 0.00 2.44 0.00 0.00 2.44 74.62 3.27 BMP Selections Practice Credit Area(acres) Downstream Practice 6.b.Bioretention#2(Spec#9) Impervious: 2.44 None Turf(Pervious): 0.61 None Total Impervious Cover Treated(acres) 2.44 Total Turf Area Treated(acres) 0.61 Total TP Load Reduction Achieved in D.A.A(Ib/yr) 5.00 Total TN Load Reduction Achieved in D.A.A(Ib/yr) 36.58 Summary Print Routing Calculations (For Phase I, and Phases I + II) CMA Properties Biorentention Basin- Phase I BasinFlow printout INPUT: Basin: CMA Properties- Bioretention Basin Phase I 6 Contour Areas Elevation(ft) Area(sf) Computed Vol . (cy) 489.00 5173.00 0.0 490.00 6091.00 208.4 491.00 7034.00 451.2 492.00 8001.00 729.4 493.00 8994.00 1044.0 494.00 10012.00 1395.8 Start_Elevation(ft) 489.00 Vol . (cy) 0.00 4 Outlet Structures Outlet structure 0 orifice name: Low-Flow Orifice area (sf) 0.349 diameter or depth (in) 8.000 width for rect. (in) 0.000 coefficient 0. 500 invert (ft) 489.670 4,' multiple 1 discharge into riser Outlet structure 1 Weir name: Riser diameter (in) 24.000 , `! � side angle 0.000 coefficient 3.300 invert (ft) 491.750 multiple 1 discharge into riser transition at (ft) 0.608 orifice coef. 0. 500 orifice area (sf) 3.142 Outlet structure 2 Weir name: Emergency spillway length (ft) 60.000 side angle 0.000 coefficient 3.300 invert (ft) 492.750 multiple 1 discharge through dam Outlet structure 3 Culvert name: Barrel multiple 1 discharge out of riser D (in) 15.000 h (in) 0.000 Length (ft) 220.000 Slope 0.005 Manning's n 0.013 Inlet coeff. Ke 0. 500 Equation constant set 3 Invert (ft) 480.000 Page 1 CMA Properties Biorentention Basin- Phase I 4 Inflow Hydrographs Hydrograph 0 SCS name: 1-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 71.600 Type 2 rainfall , P (in) 3. 500 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 3.691 peak time (hrs) 12.002 volume (cy) 482.068 Hydrograph 1 SCS name: 2-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 71.600 pe rainfall , PT(in) 2 3.700 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 4.132 peak time (hrs) 12.002 volume (cy) 539.770 Hydrograph 2 SCS name: 10-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 71.600 pe rainfall , PT(in) 2 5.600 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 8.853 peak time (hrs) 12.002 volume (cy) 1156.396 Page 2 CMA Properties Biorentention Basin- Phase I Hydrograph 3 SCS name: 100-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 71.600 pe rainfall , PT(in) 2 9.100 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 18.899 peak time (hrs) 12.002 volume (cy) 2468.717 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 3.689 at 12.00 (hrs) discharge (cfs) 0.828 at 12.32 (hrs) water level (ft) 490.353 at 12.32 (hrs) storage (cy) 290.116 Hydrograph 1 Routing Summary of Peaks: 2-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 4.130 at 12.00 (hrs) discharge (cfs) 0.958 at 12.30 (hrs) water level (ft) 490.472 at 12.30 (hrs) storage (cy) 318.619 Hydrograph 2 Routing Summary of Peaks: 10-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 8.849 at 12.00 (hrs) discharge (cfs) 1.717 at 12.34 (hrs) water level (ft) 491. 507 at 12.36 (hrs) el , storage (cy) 587.901 Hydrograph 3 Routing Summary of Peaks: 100-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 18.891 at 12.00 (hrs) discharge (cfs) 12.611 at 12.12 (hrs) > " water level (ft) 492.435 at 12.12 (hrs) storage (cy) 861.723 Mon Apr 06 14:48:38 EDT 2015 Page 3 CMA Properties Biorentention Basin- Phases I and II BasinFlow printout INPUT: Basin: CMA Properties- Bioretention Basin Phases I and II 6 Contour Areas Elevation(ft) Area(sf) Computed Vol . (cy) 489.00 5173.00 0.0 490.00 6091.00 208.4 491.00 7034.00 451.2 492.00 8001.00 729.4 493.00 8994.00 1044.0 494.00 10012.00 1395.8 Start_Elevation(ft) 489.00 vol . (cy) 0.00 4 Outlet Structures Outlet structure 0 Orifice name: Low-Flow Orifice area (sf) 0.349 diameter or depth (in) 8.000 width for rect. (in) 0.000 coefficient 0.500 invert (ft) 489.670 multiple 1 discharge into riser Outlet structure 1 Weir name: Riser diameter (in) 24.000 side angle 0.000 coefficient 3. 300 invert (ft) 491.750 multiple 1 discharge into riser transition at (ft) 0.608 orifice coef. 0. 500 orifice area (sf) 3.142 Outlet structure 2 weir name: Emergency Spillway length (ft) 60.000 side angle 0.000 coefficient 3.300 invert (ft) 492.750 multiple 1 discharge through dam Outlet structure 3 Culvert name: Barrel multiple 1 discharge out of riser D (in) 15.000 h (in) 0.000 Length (ft) 220.000 Slope 0.005 Manning's n 0.013 Inlet coeff. Ke 0. 500 Equation constant set 3 Invert (ft) 480.000 Page 1 CMA Properties Biorentention Basin- Phases I and II 4 Inflow Hydrographs Hydrograph 0 SCS name: 1-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 88.600 Type 2 rainfall , P (in) 3. 500 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 7.804 peak time (hrs) 12.002 volume (cy) 1019.378 Hydrograph 1 SCS name: 2-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 88.600 Type 2 rainfall , P (in) 3.700 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 8.424 peak time (hrs) 12.002 volume (cy) 1100.415 Hydrograph 2 SCS name: 10-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 88.600 pe rainfall , PT(in) 2 5.600 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 14.474 peak time (hrs) 12.002 volume (cy) 1890.654 Page 2 CMA Properties Biorentention Basin- Phases I and II Hydrograph 3 SCS name: 100-yr 24 hr Peak SCS Method Storm Event Area (acres) 3.270 CN 88.600 Type 2 rainfall , P (in) 9.100 time of conc. (hrs) 0.2400 time increment (hrs) 0.0200 time limit (hrs) 30.000 fudge factor 1.00 routed true peak flow (cfs) 25.949 peak time (hrs) 12.002 volume (cy) 3389.658 OUTPUT: Routing Method: storage-indication Hydrograph 0 Routing Summary of Peaks: 1-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 7.800 at 12.00 (hrs) discharge (cfs) 1.592 at 12.34 (hrs) water level (ft) 491.296 at 12.34 (hrs) 2 storage (cy) 529.841 Hydrograph 1 Routing Summary of Peaks: 2-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 8.421 at 12.00 (hrs) discharge (cfs) 1.667 at 12.34 (hrs) water level (ft) 491.422 at 12.36 (hrs) storage (cy) 564.110 Hydrograph 2 Routing Summary of Peaks: 10-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 14.468 at 12.00 (hrs) discharge (cfs) 7.485 at 12.16 (hrs) water level (ft) 492.159 at 12.16 (hrs) storage (cy) 777.105 Hydrograph 3 Routing Summary of Peaks: 100-yr 24 hr Peak SCS Method Storm Event inflow (cfs) 25.938 at 12.00 (hrs) discharge (cfs) 20.973 at 12.08 (hrs) water level (ft) 492.846 at 12.08 (hrs) storage (cy) 993.203 Mon Apr 06 14:47:33 EDT 2015 Page 3