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HomeMy WebLinkAboutWPO200600048 Plan - VSMP Minor Amendment 2018-11-24SITE DATA: TAX MAP PARCEL AND OWNER INFO: TOTAL SITE AREA: SOURCE OF SURVEY: SOURCE OF TOPOGRAPHY: COUNTY, STATE: MAGISTERIAL DISTRICT: WATER RESOURCE AREA: WATERSHED: ZONING: L PARCEL 61-158 NEW BELVEDERE, INC. 610 WEST RIO RD CHARLOTTESVILLE, VA 22901 5.91 ACRES (PER ALBEMARLE COUNTY RECORDS) 5.75 ACRES (AFTER TMP 61-154E OFF CONVEYANCE) WW ASSOCIATES, INC. VIRGINIA RESOURCE MAPPING 751 MILLER DRIVE, SUITE 2-A LEESBURG, VA 20175 (703)777-8799 ALBEMARLE COUNTY, VA RIO DEVELOPMENT AREA - NEIGHBORHOOD UPPER RIVANNA RIVER NMD (NEIGHBORHOOD MODEL DISTRICT) ALBEMARLE COUNTY, VIRGINIA 7/27/2018 now,towamma-, Sheet Title A- A I r PRE -DEVELOPMENT DRAINAGE AREAS C2.0 POST -DEVELOPMENT DRAINAGE AREAS C3.0 STORMWATER MANAGEMENT FACILITY C4.0 ROUTING CALCULATIONS C5.0 SIMPLE METHOD WORKSHEETS AND COMPUTATIONS z N r. VA W W uj v S6 c C U U >�o O v 0_ - Lu Lu u v w � U will .♦, r ♦rill� SHEET NO. a O Co.O L gma • C r oal VICINITY MAP 1" =1000' OWNER/APPLICANT: NEW BELVEDERE, INC. 610 WEST RIO RD. CHARLOTTESVILLE, VA 22901 CONTACT: STEVE KROHN TELEPHONE: (434) 242-6122 EMAIL: SKROHN@RESORTSCOMPANIES.COM ENGINEER OF RECORD: TIMMONS GROUP 608 PRESTON AVE. SUITE 200 CHARLOTTESVILLE, VA 22903 CONTACT: CRAIG KOTARSKI, P.E. TELEPHONE: (434) 327-1688 EMAIL: CRAIG.KOTARSKI@TIMMONS.COM Sheet List Table Sheet Number Sheet Title C0.0 COVER C1.0 PRE -DEVELOPMENT DRAINAGE AREAS C2.0 POST -DEVELOPMENT DRAINAGE AREAS C3.0 STORMWATER MANAGEMENT FACILITY C4.0 ROUTING CALCULATIONS C5.0 SIMPLE METHOD WORKSHEETS AND COMPUTATIONS NUMBER OF SHEETS= 6 APPROVALS ALBEMARLRE COUNTY ENGINEERING 4 M E N O N � a 0 E ai E Lu W > 3 aU.0� U. uJ O d J U —L atoN zus O �x oa 3d s= 151r" > � a rn O N � M Ln GO J 0 Lu (.o I_ ui 0 _ U M 0 S 0 W uj U a z O 0 z I O a u V) uj 0 z 0 U) LLJ z uj w 00 Lu Lu 00 ce� DATE 07/27/18 DRAWN BY A. MABEE DESIGNED BY J. WILSON CHECKED BY C. KOTARSKI SCALE NIA 16 cn 2 U N N O (6 ° T ujO v Z) Q z z Q v -0° H G O W > z N Uc @ W W uj v S6 c C U U >�o O v 0_ - Lu Lu u v Z) Q 0 Q -0° W z Lu Uc @ v y J m � Q o 0 J E� Uc @ Cc W v S6 c C v y m � 0 xn ° Uc @ U � � C N O m S° a u°, o ]OB NO. v w � U 41812En SHEET NO. a O Co.O L %'i \t'i •' 1 ' f : ,' -f ii �. : r ) , ..., ! ,r _ _ _ -- E \`\ -_ Ys; / /• _ � t j ` , _ 1. i .t 1 4 n f ! i , r q t f t f '1 :d. % , , , t j - _. / -.. �9pxs i ' r 1 t , \ I l .,. i f k J tl _� p�`j q�y,,,y I 1 \ I •1 . �rr Yt i ., :tf (SHEET s 'yj !, , l f , f ! r 1 \ 1 I i , i i r" j f _ s f i 43 r !' f ^ f' \ r _ _ , 1 / < , , 3 1' i , , r _ 1 ` � v 4 _ , $p } i^ , l C„ 3 M1iC�^ - l r r 1 `t J , t _ t 4 1 , 1 - \ I _ I r' f t 1 £t 5 .t" \ S 't i • !A tl' •f / i 4 r : , ir f' , ! t_ 1 h , _ ', ` ♦ ,, ! -`-__--..,, f ,,, . , t ,I . , f !: , , _' ( .., ' . i t 't, ._ q3y e 1 va. r K r1.. , ! , l `t 1 4- t , j {c %E• -r r I' 1 t of i r , r F /r , f: - , - r !- it ,1 t S^ €st } t i i 1 f! - t1: \ t P' VVVVVV f'• — ` ti S i r i f i ! •r t 'F Ff i t, 'rr • r r %i ^ ( , S f t \ i 1 I S -LEGEND SUB AREA TC PAT H ,•, / Ff ] PDf X.%.,1PERTY` LIN -E. SOIL BOUND) r } k f t h J r t,t. • €• - x .i: i' e ( B f" i f }• `t £ 3 2 f ''ij \ � wwurruwr +f. t' f tt fi J" ' �f RRtt 'f ei t t t 1 i'f / f 1 ,t t ! - v rr Y I 1 { ' r r % A I ✓ f` f1 'I f( c.Z xr, � r �'¢ggtt LT 1 i.. t \, r , rJJf /` f Tx f i ti f f? 1 , 1 1 <F i 1 / - i )' i 3 f k p _ 5 ,j Jr s c t' v'L f •t r f' $ i= f, t f £ } rF r f `! G 'f , t •f ¢ t/ 1 DRAINAGE AREA , TCP Ar-',rH DIVIDER Y, , V v t �t f l % r L r ! # �, -'- }1 �/ j ! ti 1 J �' i }.115; il' ? tt f 3 {( "t `? } \ .�-..-.,:.z..,rt,+' `��',J ,t '\ •\ '\� __.. i,!/ -,i J � - ANALYSIS POINT i 15 , i!: } � , � ! , i , i f i £ra f .t :t.. ii „% - f I 1 i ' i • /i ` ,' f "f = f i '` 3•y £ i f. v''? .it.r. � 1 / 1 i 21 13 f � r , � t �.\' t -"- ' - li 1 �,' - ' 1 /,•�"'. % f r J r t`,- � •-� 1 i ; t � .\ 2 1 ) f f E f it i• }` i . 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S / `� \ (;, t '�M,� j' �a..� ,:,,,,// 4, \t . t� ,, .. ,.. .,, .,/. % f- •f �`i ,1� �Ijt1l( �.. :< ,�- ,__.: � � f `f i 1'' % r it •F ��''f}:'i j c (f �`: �s X' f i 32 ( /' S { `� ` ; J P31',I }, *} f t i i( ,J t i it {!'fr f --p y����� �. / r .•F- r•'- i; r•-" , i, ?Jf,�f'w �.. 3 I '�'✓ ,` - � r ! 00 , t r c ' n 4 --- , r , f i , , , i qq ) Q r , 1 I •? \ `*� ; Ei �+''f"� f "� '7'% � .t, ,�,t,.,;''t^"'s; � a\:,Y �` 1� 3 . {!j' i • ,t � ,. - .. r � SCALE 1"=100' PRE -DEVELOPED DRAINAGE AREA MAP FROM WP02006-00048 0 100' 200' L M E O o N V N > E E N W Lu j LL LW O ¢ _j U co .J C) — tP W H � O O N Q N d- 117 z � � 'm'j- ,--t Q � X _ >° i, -- r Ln N d W J ID h z 0 CL U V) W z O' V/ i\ --I W !Y U) z cW L 0 U ry W 0- a W C/) W DATE 072718 DRAWN BY A. MASEE DESIGNED BY J. WILSON CHECKED BY C. KOTARSKI SCALE 1"=100' (U N O to (6 L Lu N O uj Q O T c 0 u �/ N Q '} N 7 <<� � 0 1..J� ry C > w c Q Lu 0 � O N L.0 Lu L ` � � 1 q 1 � 0 �O g o (D LLJ T z ae� CC) (D O /1j-0 Q LL j T 7- O LLIC N U) s 0 o LLJ Ofy N W - Z N a- O m Q X tll O s 0 N O Q w O 0-0) iU C N u O to U = N � O U U c � v E� L)Ca U Ca O `O to 4 U _ JOB NO. on o � U 41812 cuN C N O C U SHEET NO. Q o 'D to In .£ If IIIIIIIIIIIIITc POST,. III(SHEE FLOW) I-ADDIT IONAL"' VIUU: p ------ - -- - ------------- A 104 Q6 I7%% IOUB AREA w. is --- ---• --- - — - — - — - II"ROP" C. lum, I I Now f. i mom 1 IIeN IIAN 9 -7, IL OUNDRY PR i CR rc no= 1 DRAINAG AREA I23 rim 20 I4) PAT IL I 13 104 ktf AN INT st '7 CRA yy t5 ------------------- 13 I05 @ 1. III23 00 lye IIIIN 0 INS JP' K 26 t ' ... !°�% 55 A** SUMPTO" Iyy IIIAlq -41RCLw"D "UB—AREA1 44 30 II"AN BE 27 is NUM I0, V"UND ON D W� baf f, G —5.0, s, fd IIIIII A (24) i37 30 I3 (D29 IATM II30 III5 30 II- - --- ------ PIPE IQ1) I37 I1-3 II301 M, 3� I-2 I2 4 it ---------- IifI III6 IIII(3 III3 % • Jm 38 IIIco co I L M E DATE ZD 07127118 CD 0 DRAWN BY A. MABEE M DESIGNED BY 1, WILSON CHECKED BY so C KOTARSKI SCALE 1" = 100' < > E LULU LU U. 0 C) LL - r, %a Ce iu _j LU -J Ln 0 UJFy ry u LU :3 U) > Ln 0 F- < - U) = Lnry 0 V) m Q) " cy-) CL Rzl- F- F- 00 —j uj LLJ LD F— 00 u U) c� LLJ LLJ 0 U U) (n 0 > > uj uj F- uj 00 00 > LU I T LU 3: Q m T—i 0 DATE ZD 07127118 0 DRAWN BY A. MABEE DESIGNED BY 1, WILSON CHECKED BY so C KOTARSKI SCALE 1" = 100' % `V �-'A / P { �{ X44 '5 L o �;{ 3 . w" �rt� ! � �� ��� fi f SSS 1 N4361 17 X tom`. ,% .,-- --_ ._- �-- __ �- --... "'� � _.� ~` � � - •._...- / ,- 1' } ` _ '�``�`�'-�� '"v-'' ,-�i' `'' --- -� ` 2� N° __ -,- •M `` --- �"' �''�-, �` �.._*.�`' ..._.., � _ •,,,� �� f l ,.-_,;.;.,�, � ` ..�-�, i � � � -'� � � � I ( It j { tt6 � � � is S - "^' �..� `-- `'^a �°"";`T -.... "�--.,� �,, .s• f ! /.-.... , ' \ { +ill' '7 ••- l �j._ _ �,,.•. °"`w' -.-..,.,,rte.. ,," .•-� '- A~ ,� .r--.... _ _ w o;'+.'--�� --�`,.,•_.*° .w., _.._� •" `l. r __.. _._. j' 4 } # cy/ . r-,,;�.��.`�.., r ' AS �` " =� _ ..__._ `" w ..�_ _._•�.. ti ��, � .` f /�� �--,-`��., � � r ��, � � � -PC " Lk h N ` ..�. •. `�`�-=-=�, � ...1.. �. � `- _ _ - �-�'�'-�-� .,_.• :ISE... _ i � � � � � � � -�.•. �..;�, _ _ '_`-_� \ `� 1 41, I PAP\ ` � � � } � K �"-�--...,��"�-....mµ.7 � ,--, /� `-. 'i�-..,,���1'- -.�. � �� �.."^.-«n+� `--�" ---�,• �_ ,n-,"`^'�" � 1 7 � � � 1 � � �`,,t � ��� \ ..,_ � �r If l / _ ti k \ . ` IF IFAS DRAWING IS A REDUCTION / `"4 `` - � `, `,\ GRAPHIC SCALE MUST BE USED 7, NJ - Al STORMWATER MANAGEMENT FACILTY No. 1A FLAN VIEW 410 VDOT POLYETHYLE E TRASH RACK (SEE DETAIL DRAWING C-21 PLACE ACCESS DOOR IN _....___..._.._._. _ ALIGNMENT WITH R JNG STEPS AND VALVE EXTEN 1ON STEM. THE VALVE EXTENSI)N STEM SHALL END AT THE TOF OF RCP RISER AND HAVE AN ADE UATE SUPPORT FROM STEM GUIDES. l 400 �..._. 48" ID RISER---,, LL ~JOINTS ANb PEN RATIONS SH LL I HAVE R BSER GASTS § AND 13E WATER T GI iT EXISTING EMBANKMEN l l 390 s iP INV OUT=3 33.95 _54L4 ----iii VDOT A3 GENERAL COAG. AND 25' CL1 RIPRAP APRON PROVIDE N66T IS -1 =1.0' MIN ��. a 04 18" IDEEPx8'DIA. CONCRETE BASE 380 410 100 -YR WSE= 402.77 10 --YR WSE= 402,03 RISER CREST•=401-00 400 2 -YR WSE=398.76 2--24" ORIFICES INV=395.00 PERMANENT WSE = 395.00 48" PRECAST MANHOLE SEGMENTS. SECURE SEGMENTS WITH 6»x18"x1 /4" GALVANIZED PLATES (4 AT EACH JOINT BOLTED TO RISER,) 390 EX, BOTTOM ELEVAr{0 =.,388.00 6" DIP CL52 OTTOM OF CONCRETE FILL=385,00 6" GATE VALVE WITH STEM EXTENSION INSTALLED PER MANUFACTURERS 360 RECOMMENDATIONS ©i "� IF THIS DRAINING IS A REDUCTION ' GRAPHIC SCALE MUST BE USED 00 (D W kN Z 'W � VERT: 1 + > + + 5' 0 5' CiK0+00 0+50 1+00 Illlllu uwuuu■luuluul u�ur 25' 0 25'. "ORMWATER MANAGEMENT.,F"ACIL7Y ±1o, 1A HORZ, 1" = ` EMBANKMENT PROFILE NOTES: CONTRACTOR SHALL SUBMIT SHOP DRAWINGS FOR REVIEW AND APPROVAL OF VALVE, STEM ASSEMBLY, AND APPURTENANCES. REMOVE EXISTING OUTFALL STRUCTURE AND CONSTRUCT SEDIMENT BASIN OUTFALL STRUCTURE FOR EROSION AND SEDIMENT CONTROL PURPOSES PER CALCULATIONS SHOWN ON THIS SHEET. EXISTING POND To BE DRAINED USING PORTABLE PUMP(;). DRAINAGE IS TO BE MONITORED AND CARE SHALL BE TAKEN TO NOT HYDRAULICALLY REMOVE EXCESS SEDIMENT THAT WOULD DAMAGE THE DOWNSTREAM DRAINAGE PATH. IF NECESSARY, SEDIMENT SHALL BE EXCAVATED FROM THE BOTTOM OF THE EXISTING BASIN ANIS REMOVED FROM THE SITE. UPON COMPLETION OF CONSTRUCTION, THE OUTFALL RISER SHALL BE CONVERTED TO CONDITION REQUIRED FOR FINAL STORMWATER MANAGEMENT FACILITY. Sediment Basin design drainage area (acres) emergency spillway: 42.3 basin volumes, (using 2' contour intervals) wet storage required (cy) (67*DA) elevation (ft) contour area (Sf) total storage(cy) 388 5554 top of darn (ft) 390 9445 592.6 392 12611 1409.0 394 15134 2474.0 3961 20050 3814.0 398 24281 W6.0 400 28775 7421.0 402 32358 9685,0 444 359833 24211.0 448 39720 39010.0 DESIGN HIGH NATER 1,(25 -YR- STORM ELEV,) r A WET ' STORAGE » WET STORAGE T 3- RE) CED MIN. V W! SPILLWAY CftST Of EMERGENCY X WITHOUT SPILLWAY RISER CREST DEWATMNO wet storage: emergency spillway: no 48 wet storage required (cy) (67*DA) 2834,1 design high water (routed) 402.7 dewatering orifice elevation (ft) 394.9 top of darn (ft) 405.0 wet storage provided at this elevation (cy) 2838.0 top width of dam (ft) 12.0 available volume before cleanout (cy) (33*DA) 1398,9 bottom of basin (ft) 388.0 (cleanout elevation (ft) 392.0 approx. bottom dimensions: 199X35' distance from cleanout to orifice (ft) (> 1) 2.9 upstream face slope: 3:1 C. KOTARSKI downstream face slope: 3:1 !dry storage: I' V=100' ;dry storage required (cy) (67*DA) 2834.1 baffles: no principle spillway crest (ft) 4011.0 length of flow, L (ft) 250 dry storage provided at this elevation (cy) 2838.0 effective width, We (ft) 125 diameter of dewatering orifice (in) 4.0 l.. I We (baffles required if < 2) 2.0 diameter of flexible tubing (in) (orifice+2") &0 collars. no runoff depth of water at spillway crest (ft) 0 `C (use 0.45 for bare earth) 0.45 slope of upstream face (Z,1) 0 etc (min) 14.5 shape of barrel (Sb) 0 [I 2yr 3.5 Q 2yr 66.6 length of barrel in saturated zone (Ls) 0 �l 25yr 5.2 Q 25yr 99.0 number collars required 0 dimension of collars principle spillway: available head (it) ;diameter riser (in) (spillway capacity, Qp (cfs) diameter trash rack (in) barrel length (ft) head on barrel through embankment (ft) diameter of barrel (in) 5.0 emergency spillway: no 48 required capacity (Q25-Qp) (cfs) 0.0 102.0 bottom width (fl) 0 59 slope of exit channel (ft/ft) 0 80 minimum length of exit channel (ft) 0 19.0 crest of spillway (ft) 0 24 DESIGNED BY PROVIDED FOR REFERENCE ONLY M E DATE 0 07127118 o DRAWN BY A. MABEE DESIGNED BY 1. WILSON CHECKED BY C. KOTARSKI >E SCALE I' V=100' ai LU -� ¢�t� LL LU Ly M L O LU z v o�Q w cn= ivN Z =�Q' o pN > M � 00 Z W Z W 1 ,D � .5- 00 LULU 0-0- -0- 0 ® ®o U..i If I O uu z F- W 00 > LLJLU r i Q Z 0 v N O s 0 2- U U 3 Q T L o ✓v z o (D L L N I� Q o 02: U. Uj W W2 �o 20 LU °Z :%' 0 < ate_ E � m E d� O Z n LCL X � X �v o� �:S o .§ �m >Y U N X N O N 6 y 2 N O rn U � O N E 7 C U C5 O � C U JOB NO. 0 o N .- W V 41812 C c C N O C U SHEET NO. n o C3. 0 u�i ami - - IF- - DATE 07127118 DRAWN BY A. MABEE DESIGNED BY 1. WILSON CHECKED BY C. KOTARSKI SCALE I' V=100' 0 v N O s 0 2- U U 3 Q T L o ✓v z o (D L L N I� Q o 02: U. Uj W W2 �o 20 LU °Z :%' 0 < ate_ E � m E d� O Z n LCL X � X �v o� �:S o .§ �m >Y U N X N O N 6 y 2 N O rn U � O N E 7 C U C5 O � C U JOB NO. 0 o N .- W V 41812 C c C N O C U SHEET NO. n o C3. 0 u�i ami - - IF- - WPO Amendment Type 11 24 -hr 2 YR Rainfall=4.00" Prepared by Timmons Group Printed 7/12/2018 HydroCAD® 10.00-16 s/n 06538 0 2015 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 1S: Pre -1A Runoff - 74.94 cfs @ 12.09 hrs, Volume= 5.106 af, Depth> 1.73" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type li 24 -hr 2 YR Rainfall=4.00„ Area(ac) ON Descri tion N 35.400 76 07/27/18 35.400 100.00% Pervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 16.5 79 Direct Entry, 27,140 Subcatchment 1S: Pre -1A 75.28% Pervious Area I`iydrograph 24.72% impervious Area Tc Length RunUff 8D .. rV 59 cfs. 14.8 75yp.11 2r 70: 2 YR Rainfall --4-00"; ai E 65. 6a Runoff Area=35.400 aic 55: Runoff Volume:=S, 06. of 45 - Runoff. Depth>1-.73.'. 111. TC=16.5 mim o 35 . :. 30 at.^ [ 25; 01. 20 " 15 is 10 �. 0 1 2 3 4 5 6 7 8 9 10 11 12 `13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) WPO Amendment Type // 24 -hr 10 YR Rainfall=6.00" Prepared by Timmons Group Printed 7/12/20118 HydroCAD® 10.00-16 s/n 06538 O 2015 HydroCAD Software Solutions LLC Page 21 Summary for Subcatchment 15: Pre -1A Runoff - 146.75 cfs @ 12.09 hrs, Volume= 9.932 af, Depth> 3.37„ Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 10 YR Rainfall=6.00" Area (ac) ON Description " 35.400 76 35.400 100.00% Pervious Area a 1 2 '3'-"4' 5 6 7 8 9 10 11 12 13 14 15 16 17 19 19 20-2l 22 23 Time (hours) L WPO Amendment Type 1124 -hr 2 YR Rainfall=4,00" Prepared by Timmons Group Printed 7112/2018 HydroCAD® 10,00-16 s/n 06538 @2015 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 2S: Post 1A OFF Runoff = 91.41 cfs @ 12.07 hrs, Volume= 5.877 af, Depth> 1.96„ Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 2 YR Rainfall=4.00" Area ac CN Description 8.910 98 24.540 74 0.390 91 0.210 88 x 2.000 61 36.050 79 Weighted Average 27.140 75,28% Pervious Area 8.910 24.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14,8 Direct Entry, Subcatchment 2S: Post 1A OFF WPO Amendment Type 1124 -hr 10 YR Rainfall=6.00" Prepared by Timmons Group Printed 7/12/2018 HydroCAD0 10.00-16 s/n 06538 @2015 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 2S: Post 1A OFF Runoff - 170.65 cfs @ 12.07 hrs, Volume= 11.018 af, Depth> 3.67" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 10 YR Rainfall=6.00" Area (ac) CN Description 8.910 98 N 24,540 74 07/27/18 0.390 91 0.210 88 SCALE 2.000 61 36.050 79 Weighted Average 27,140 75.28% Pervious Area 8.910 24.72% impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.8 > E Direct Entry, Subcatchment 2S: Post 1A OFF 0 1 2 3 4 5 6 7 8 9 10 11 i2 13 I'll 16 17 18 19 2Q 2B 22 23 24 Time (11.4 WPC) Amendment Type 11 24 -hr 2 YR Rainfall=4.00" Prepared by Timmons Group Printed 7/1212018 HydroCADO 10.00-16 stn 06538 0 2015 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 3S: Post 1A ON Runoff - 23.07 cfs @ 12.06 hrs, Volume= 1.523 af, Depth> 2.91" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type it 24 -hr 2 YR Rainfall=4.00" Area (ac) CN Descriotion 3.660 98 2.140 74 0.480 98 6.280 90 Weighted Average 2.140 34.08% Pervious Area 4.140 65.92% Impervious Area Tc Length Slope Velocity Capacity Description min(feet) ft/ft ft/sec cfs 14.8 Direct Entry, Subcatchment 3S: Post 1A ON 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) WPC? Amendment Type 1124 -hr 10 YR Rainfall=6.00" Prepared by Timmons Group Printed 7112/2018 Hydr)CAD® 10.00-16 s/n 06538 0 2015 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 3S: Post 1A ON Runoff = 37.32 cfs @ 12.06 hrs, Volume= 2.529 af, Depth> 4.83" Runoff by SCS TR -20 method, UH=SCS, Weighted -CN, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type 11 24 -hr 10 YR Rainfall=6.00" Area (ac) ON Description 3.660 98 2.140 74 0.480 98 6.280 90 Weighted Average 2.140 34.08% Pervious Area 4.140 65.92% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.8 Direct Entry, Subcatchment 3S: Post 1A ON WPO Amendment Type 1124 -hr 2 YR Rainfall=4.00" Prepared by Timmons Group Printed 711212018 HydroCAD®10.00-16 s/n 06538 @2015 HydroCAD Software Solutions LLC Page 12 Summary for Pond 4P: 1A Inflow Area = 42.330 ac, 30.83% Impervious, Inflow Depth > 2.10" for 2 YR event Inflow = 114.45 cfs @ 12.07 hrs, Volume= 7.400 of Outflow - 34.98 cfs @ 12.33 hrs, Volume= 5.320 af, Atten= 69%, Lag= 15.6 min Primary - 34.98 cfs @ 12.33 hrs, Volume= 5.320 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 397.58'@ 12.33 hrs Surf.Area= 23,398 sf Storage= 137,362 cf Plug -Flow detention time= 166.2 min calculated for 5.309 of (72% of inflow) Center -of -Mass det. time= 68.5 min ( 898.5 - 830.0 ) Volume Invert Avail.Storage Storage Description #1 388.00' 405,270 cf Custom Stage Data (Prismatic)Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq -fit) (cubic -feet) (cubic -feet) 388.00 6,554 0 0 390.00 9,445 15,999 15,999 392.00 12,611 22,056 38,055 394.00 16,134 28,745 66,800 396.00 20.060 36,194 102,994 398.00 24,281 44,341 147,335 400.00 28,776 53,057 200,392 402.00 32,358 61,134 261,526 404.00 35,833 68,191 329,717 406.00 39,720 75,553 405,270 Device Routing Invert Outlet Devices #1 Primary 388.00' 24.0" Round CMP "' _Round 24 L= 80.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 388.00'/ 383.95' S= 0.0506'1' Cc= 0.900 n= 0,025 Corrugated metal, Flow Area= 3.14 sf #2 Device 1 395.00' 24.0" Vert. Orifice/Grate X 2.00 C= 0.600 #3 Device 1 401.00' 12.6' long Sharp -Crested Rectangular Weir 2 End Contraction(s) Primary OutFlow Max=34.97 cfs @ 12.33 hrs HW=397.58' (Free Discharge) t-1=CMP Round 24" (Inlet Controls 34.97 cfs @ 11.13 fps) 2=Orifice/Grate (Passes 34.97 cfs of 37.98 cfs potential flow) 3=Sharp-Crested Rectangular Weir( Controls 0.00 cfs) WPO Amendment Type 1124 -hr 10 YR Rainfall=6.00" Prepared by Timmons Group Printed 7/12/2018 HydroCAD® 10.00-16 s/n 06538 O 2015 HydroCAD Software Solutions LLC Page 27 Summaryfor Pond 4P: 1A Inflow Area = 42.330 ac, 30.83% Impervious, Inflow Depth > 3.84" for 10 YR event Inflow - 207.95 cfs @ 12.07 hrs, Volume= 13.547 of Outflow 43.06 cfs @ 12.42 hrs, Volume= 11.423 af, Atten= 79%, Lag= 21.4 min Primary - 43.06 cfs @ 12.42 hrs, Volume= 11.423 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 402.25'@ 12.42 hrs Surf.Area= 32,794 sf Storage= 269,691 cf Plug -Flow detention time= 133.7 min calculated for 11.400 of (84% of inflow) Center -of -Mass det. time= 65.3 min ( 879.0 - 813.7 ) Volume Invert Avail.Storage Storage Description #1 388.00' 405,270 cf Custom Stage Data (Prismatic)Listed below (Reeaic) Elevation Surf.Area Ine.Store Cum.Store (feet) (sq -ft) (cubic -feet) (cubic -feet) 388.00 6,554 0 0 390.00 9,445 15,999 15,999 392.00 12,611 22,056 38,055 394.00 16,134 28,745 66,800 396.00 20,060 36,194 102,994 398.00 24,281 44,341 147,335 400.00 28,776 53,057 200,392 402.00 32,358 61,134 261,526 404.00 35,833 68,191 329,717 406.00 39,720 75,553 405,270 Device Routing Invert Outlet Devices #1 Primary 388.00' 24.0" Round CMP -Round 24" L= 80.0' CMP, projecting, no headwall, Ke= 0.900 Inlet / Outlet Invert= 388.00'/ 383.95' S= 0.0506T Cc= 0.900 n= 0.025 Corrugated metal, Flow Area= 3.14 sf #2 Device 1 395.00' 24.0" Vert, Orifice/Grate X 2.00 C= 0.600 #3 Device 1 401.00' 12.6' long Sharp -Crested Rectangular Weir 2 End Contraction(s) Primary OutFlow Max=43.05 cfs @ 12.42 hrs HW=402.25' (Free Discharge) Z-1RCMP_Round 24" (Barrel Controls 43.05 cfs @ 13.70 fps) �2=Orifice/Grate (Passes < 75.60 cfs potential flow) 3=Sharp-Crested Rectangular Weir(Passes < 56.12 cfs potential flow) i a M E DATE N DESIGNED BY 07/27/18 O O CHECKED BY DRAWN BY SCALE m v 1=100' cv � > E ai E _LU o ®U. L ,� UJ 0 0 ALU � v 0 z a- LU 1-4 a ® N U� �M Y moi -,--q _ U 3:0 x cn 9 Q � t E W 0 U) O MUa� r_ L U) ® �, > U) � v� 00_JCD ww LU 00 W c� � a. a 0 z LU UJ t� cn u) O ww CL/ C[� LU ® 00 00 u_JLU U ' z O i!1 DATE N DESIGNED BY 07/27/18 O CHECKED BY DRAWN BY 0 J U _ N N a 1__ Q C Q 0LUT 0 < OMO z )-� :2 a --s o U r s ` N C lB U U U 0 LU LLJ _J iY CO CL LL1o� 11)0 W 2z >� _ 0 o T� ca O N LLJ C N �C D_U LU O C � N Z n O0 2 v Q :5E x m F N o 0 0 0 o Q� o N c6 X c O O O U L- 2 N rn O O N U C O N EC U ru O � C � 4 U _ ]OB NO. ;o» o In.- lB U 41$.22 C to O C U SHEET NO. Q o C4. 0 s E A. MABEE DESIGNED BY J. WILSON CHECKED BY C. KOTARSKI SCALE 1=100' 0 0 J U _ N N a 1__ Q C Q 0LUT 0 < OMO z )-� :2 a --s o U r s ` N C lB U U U 0 LU LLJ _J iY CO CL LL1o� 11)0 W 2z >� _ 0 o T� ca O N LLJ C N �C D_U LU O C � N Z n O0 2 v Q :5E x m F N o 0 0 0 o Q� o N c6 X c O O O U L- 2 N rn O O N U C O N EC U ru O � C � 4 U _ ]OB NO. ;o» o In.- lB U 41$.22 C to O C U SHEET NO. Q o C4. 0 s E Short Version BMP Computations ForWorksheets2 -6 Albemarle County Water Protection Ordinance: Modiffed Simple Method . 1 �., I- - I— �. 11178 , 100% . 11, 178 I C � 98 ...... .... ...... PRO'VIDE SWM FOR Plan: Belwdere Phase I Water Resources Area: Development Area EQUIV.IMP. SOILGRP-CN _­... 2 I 11 , " " �1-1.11,11,�..�'�.,.-.�,�-.��.�-��� ....... . ­ 1--.__..-__ 26,234 : 1000 � ,6 � ­ . ..... � .. .... � ------1.__ .. ...... ...... .... � .... I 26,234 1 I _1111 11 ­_,.�­. 11111_,-� ­­­ . ... C _­­ . : I I— - � 9B � - .... _ __.. BELVEDERE BLVID _1_111 1. ­­­- _... _­­.. 1- ...... . � ­ - ­ ­­­ , ­­. ...___ ,, ..", �- --._.1._1-- I..., 1111-1-1-1-11-11 .", I � I I I . . . - I.. -1. .. - � I 11 3' -11.1-1111---111- . , , 4,459 � 0% � -1111-1-1. ­ J. _. "" - __ __ __­ ... I 0 � -11 - ,_ _�____ � ___ ___,______-._1 � . 74 I I AND THE P star: J. WILSON Date: 2018-09-17 107375 4 98 3,47S � IMA � d 3,476 � I , G � 98 C - � ... � .... � ..... � _ . . ... .. .. ........ . .. __ ._ - , _. I 11r4m..__..__­1___.1 --- ---------- --- 1_1_111 ......... � --- __­ - -- ------- . ....... __. , , - _ , ­.. I ... I 4 ...... - 5 1.11,11, __ ­ -­­ _--­­­­_ - - 164"619 0% I w � - ­­­­­ 0 � t -- C ----- 11__1-..._-_-._--.._ -,--"- " ,-,- : 74 � (UNDEVELOPED) 4519 0% 0 --..-..,-- 6 - ------ - ­.­ --- � -11-111. �,-�,�"�ll,�.11-�11--l�l----"..-�.,�.,.-.� 4,867 � 0% ..�.-I-I�--l"-�ll.,�..-.",-�.-� - ----- -- _ I I 9,878 � 0% � 0 : - . ..... ­ - .... �& ... 1- 0 � C 11 ­­..­­­ 8 � 74 I ROUGH GRADE !PAD Project Drainage Area Designation SVVM Facility #I A - 8 --1-1. 11924 0% - I . ..... I .... - ....... . _ -- - -------- , : I I � I -1 -11111-1 1:__­_1­ 4 74 c ­� - - --ql-- -_ 7 WITHIN ITS � ­­.- 1. � -- ----- 1.11 - � ... .. I. ­ . I -­­ , 12314 a . ..-._1_-__1._11 9 91 1 6,675 :1 fm _._._..1. ... ­­ - 13,561 - 721% e 0 . I - - ....-1 91764 -� B C 61 ...... .. _­­__ 91 RESPECTIVE L storm pollutant export in pounds, L = [P(Pj)WI2J [ C(A)2-721 11 10 62329 0% �­­ ­­ ........ _ _ 9,107 :: 72% � ­ ----- I ---- - ­;­ - - 6,%7 i ----- - _--i..".. B � 'lH­ DRAINAGE AREA, RV mean runoff coefficlent, Rv:z 0,M + 0_0MJ) 0 _-1--_- If 74 i��'Ii ­ ... -11f ___1i-_--___,_ 4 I 1 . ..... 4-_-_-----_ 13,149 ! B 1- ... ­­­­ ­­_ c , 61 -0 SWM F R THE) small storm correction factor, 0.9 : 14 - . . . . . 11 .... I� , '. I ­ ____ , .1 144,­i��4 I 1-11- . 61� 0 1 6- - �­ 5_5 FUTURE 1 percent imperviousness i 3259 -_--b .... 13 -1- - � 1 ­­ ---_..._1....- ......... I ... -.1- .. ...... I ; 77,&153 IOVX, I 1".. I ... ­­­ I - -'- - 77,853 . __i�- � __ �16 __ - DEVELOPMENT P annual precipitation, 40 in Albemarle ­­_' 17 ­­ ­­­ ............ 14 �� 1-1-1 - .1-1 ­.- � . 1. ". 1". 393,977. 0% ;; --.11 1-11 . ....... . ..-1-----..-- � 0 1 � ­­­ C 1-1 .: ... 1-1- 1111-1-1 ... � , � , J� WITHIN BLOCK I A- i A project area Ina in subject drainage area,_ - 5887 ­.- I - 5 -1-11 - 1-1 � 1 , ­­­­ ..... _­­_­­ .... - I . 162,M ! 0% � � 111-1-111- 0 � . C � 74 C C pollutant concentration, mgA or ppm target phosphorus 20 1111. I ... ­­­ 16 1 . � . .­­­ .... I � ---1-1- - _-.1-1. I... --- 121,116 � 0% , ­­, .... � ---- ­ ......... � 0 1 1 - ....... ­­ C I.. - -,.-. _ � � 74 WILL BE SUBMITTED f factor applied to RR 1919 ....... � .. ... ... . 17 -11, I -1�-.--.�.-�"..-"�-1-�.�.-.-."..I ... ..... ".-.-.".11.�..,.�..--., 3 259 : IW16 ; ... 3,259 $ � .......... . 0 � 98 W / THE FINAL / -e V required treatment volume in cy, O.T over imperv. area = A%4r, q0,&12y27 23Pavement 1-1- 18 ... ­ � , ­- _­ _­­�,4� .... I I --1 I I M 1 q . �� " F : �­'_` ­ 5,478 I ... - - ' '' 111-1-1:1 - __ .... ... ..... � - ­. _ - SITE/SUBDIVISION RR required removal , L(post) - f x L(pre) 4831 � - ..,. ... .1 ... I 1. 9 11--- ­­­­ .1.1 ... --1 . .... ..... , . __ .... -1 __ 3,2 . 77 ­­ ! .. ..... I . W16 ....... � � ------ .... , _il ..... � ­11­��,.i��, - 3, , 2 , 77 __-1. : - " ­­­ _.-_-1.-. - C --- ­­­ , _ _ _P� _ ,. _ I PLAN. %RR removal efficiency, RRIML(post) 26 20 z , I6*11-1- I �1, 1 i I ; I C I 98 Lii LU ­­­ - 21 11-11-1. - 98 .,.-.. 3, 1 8 1 W ­ I 11 � I I 000/0 I -1 ...... ­ -.1. � ­­­.- �._ ,_�316� ....... . I � ......... I I �:­­­__­�� .".._.,....-1111.1111_ 0 ", . 1 98 I-. C ��oye�r co�npii#atier�jval - -,s in feet & squa., 11 . ...... I- ­ -1 "I 1111_,.. ... �� -1 I... ­ - � ­ . ­ . I - _". , , � _lmip,�Ttp� Ue .... I � re feet) _......" � 11 - -111-1-1 � 11 1. . I 22 4125 100% -11 _­­ ­ 11-i_ , 11--l-11- 1j.11--111 I 4,442 1 IWA ' ------ 4,442 : ------ _­­­ G ... � ....... _­ 98 Pavement iltem ; ...... __.______ . . .. ............. 1111-1111_.___ ------ . ..... .. ___ - ­; - ­­ ; ­­­_____'___­_­_,_­­__ - - - - - "' I , - 111.1 ---.1-1 23 98 .-_i-11__ -1-11- I I.- --- 100% ; Imp - ------- -1---1-1___- 0 .... .. . ....... _ _ 98 C �-­_____ IAi,' t-deve(opment pr�-de�lolpme!4__ . ..... �­ ­­­ ­__-, � --- ""�l-"".---�-�.11-11�l-.,-..,.,�I I -i-- . ...... � ­­ ­ .. . .... -_ _ _ , _ _ . . I ' tArea -, '. . ' ­ I .... �4.1­ � -.._-_...____11 ... ­... __ ,�!�_, __1_-_-_1-___._1 -1.11 1,983 � 100% 1 . - ... 1�,��­­ ..... 1i - _­ --------- ­­­_ '­ � 1,983 - Ii .... . .. '-- - ­­­... 0 " - �, .... - --- , .... -1 V 98 _' ­_ ' - Open Space (Good) I Paved Le Width Mai I I �"h � .. . - I - - 1i Widt.hsub(a.IaI_., .......... -­­­ --- ­­­___.��__ I I t : . . � I - I . 25 61 : : 4,462' � . b I C I I I I : I I , I ; I . .... � �. -1: ... ­­ ..... :.--_1--.1---1-- . ­.. ­ .. . 1. - �. I 11. ­ I 35 I ­ ,. 26 .. ... ._____.._1_.11_-.J__-._-- - ' �1­11111­11. 4,831 1� 100% : ---,-1__,_1..__.,..... 4,831 1:C: - I ..­­­ . ...... . - ­­­­ 98 � - -------- ­­ . ..... Pavement I i ; . I . ; � . 1 � .I . � I - �11 ..... -11--_.----i- � ....... - � _� � � " � � ; . -1 .1 .. ­­­ 27 I.. ­ I I _-_11 ­.. _1111.__._1--_- ------------ -.._W-1--_- 21479 1, IWA � - I..., _. ...-11.1- . 11 I ... 11-1 ........ I ...... 2,479 1 I . �� .1. I 0 ..1. . . I � 98 .1 ... � I ­ - C r I I � I I I I � . I � � ; - : : -_1_----- ....... I ....... ­­ ­­­, --- �� .... 1. I.. 1-..", -1 - ­, � ,. � ­_ 1. 1. I I... �. I— � .... 1. � 1. -.1 ... I... � I I , ! � : � ; I 1 ; ; ys � � I . I � I 27 8A . , 29 8794 0% 674 ; I W/o ­­ - __ _ .- --- I I - ,9 - 5 . 7 ...... � ­_ 100 - % .... I --- ; -1-1 ----- 674 . .. ..... - I I , . 9 . 57 ---T- ........ ----- I . ..... ....... _--11_- C _­ C ... -1 ..... W � ­_ I ..... ­-, 98 - ...... � _: ___ __ - - Proposed Development p I � � � � I .1 .... � .... - �� I 71. 1 1 I., ­ - I .. __1111-1111 __ I -11 � - � ­­­ ­­'.., _ --11 ------- ---- ­­_.­_,_­ - 1. -.1 ..1. � .... . Driveways �Lengfq_. "Width no. SuNotal , Lr'n no, subtotal � . 1-1-.1-1- - 1-1-11-. --1 1---_ 1, 1-1-1 - - ­­__­ I ­ 111.11, "..".1. I— ­ -11 -1 � I -1 � � . .....­­ ­­1 � , I - ... ­ 30 - : : - -�,.�.-�"...,-..'�.,�,-��-..'�1-11�������,�,�.----�,� 4,064 1 WA � -.1--4.125._,...,,.:.,...__ , " "I * ..... '___` --l-olo : . 4,064 i . ..... . - -, -4 ....... 4,125 � C , C s !�8 - , , - "" 98 C . I .: ; ;and walks . . � . . � I 1, . � : r I ­ , , _ _­ ... ­.. 1-1.1.1. q - � . . : � I . � I J I I � . . � � I . . I -,.------1 .­­!�­_­_­.­',­­:' - ­­­­­..... ­­. ­§i"16�1­111­ I z-�,�.."."".�,,�.,:.�,,�,�.,.,- � I . 11 2054 100% -11166-I. -.1 ... _____..1--- �� ....... ­­­­ ' ..... ­­­ : ­­­­­ .... Open Space (Good) � I . . � - I I I a. I I I- . �, ; I I . ... I 1111 ii I I! � .11.1. I 1. 1'. , , 1 'i 616 i 11 I-. , � C ,11. � 96 I 1. 1. C1 .,. I Ill 111-1 ... 1-..__-._.__- ... �.,,,...�,,-..�,-�..,..-�.,�-.�.-,�-��-,.-�.,;.,-,-.,l.-II-�.I.�'..��.I....-� ......... .. � ...... . . ... ..... . .1�..,..,.,,.,""..,..","'',."-I - .1 - - ----- I—_ I ... _. Area 3 Area 4 � I Am2 Am3 Area - .. I.. - Open Space (Good) , 9,4� I MIG ; 9,457 I . G I 98 Existing Buildings Parking Lots Area I Area 2 'Area : I I � I _. -11- I.. ­ :1'. -1i, 11 11. __- --17- -1.1-1. ­.­­', - .- - - � __ - I � 11- 11 - 1-_1.--.- ........ .. .... .. . ­..... ­­­ 11- �- -1-1-1, I 11 34 �­ - i� 1 -1 I . On-site 0 S( ) � q 1--l�-1".�.r-11.1,�ll".�'-�'��-'-..�'�'�'-'-'-" 68,9W 1 !- 90� 1 ­­­ --­ - � - ...... 0 � � z .... �. �..., C � ­ 1. 1- ­­­ ; 70 � I ; : . I . I . .� I � . ; : I . � I - . � . I 1 1. _-.11 ­ � ­­­ 1, - -1 ­_­.­_­. 11. I., - , I- ­. * I 0 . ­­_ . - -1 ai - .. I 1. . - ­­­. ­ .- I.- - -'--: --- bpen$pace (Good) ' : ... I ... -.1.1-1.1--l... ­ � ... I..-- 21,327 ; 004 i ; t I __ .. . .... �.,�."�,.�.".,�'..--.1.1.� 0 i I C I '. 74 439937 sf - I �Grawl areas Area I Area 2 : : iArea 1 A"2 subtotal �,subtotal. -.1--11-1- I...1-1.11 . .... 1. ­,­ ----1 ---- �­: --I.......--- I ­­ ­... 1-i I ­ ­ - I-— 36 ­1� I— I ­ � I I ... I �. 1 .11.1 11-11 ­_­ � : On,sge Woods (Good) '; --1 ... 111. ­­ r,.,_, __d,�,_ _i I_- 64,311 :___ � . ...... � ------- - _--1 ...... 0 � � .. ­­ � C ._ ­.. ­ ­­­­­ ... ; : 70 - f._ �­_ I I .I . ; � I x 0,70 = I x 0.70 = 1 � I ,. I ; e I_ __ , __ .___ .. .... ,__._.._ 11'..., "..­11A."i., � ­.­­ .1-1.1.. � I ­­'­ - ­ I.- ....... - "' ­ ­­ � , 11 I I 11-1 37 � ­ - I.. ­­­­ I-— I ­.­... � z Porld surbee : ... ... ­­ ­­...." " _11-.1.1 18,2-56 ; 16064 I ... i��.. I -i ... ­.. 18,2 I I-., � ­ C ''. I � I � I . r' 11" I � 98 .1-1 ­­ 269388 sf � Area no, subtotal , I Area no, I . : Structures � 11 -11-1- ­­: subtotal.,. ; �� -.11.1 :� � - -1. I - ... 1-111, I - ­­ �� . .., I I I . 1. I—. ­­­­ 38 � I I - I - ­ -11-1_11.11 � Pond Surface : ­ 1111: 1111.'....... 6,200 ` 10MG � � 11-1 ­ 6,200 .... ... 1.11 D .... ... . , 96 I . ; p I I I , I _1 1 " 11-1-1.1--l-l-,-1-­ ­ ; -1.1 -1 "...-I 11 .1 - .. ­ ­ � .. � I I Shallow Conc. Flow ­­ ­­ _--_1__--_.__ 39 I 1.1-1 ­ ­ ­ 11-1_1 ... 1. I I; : O"ite Woods (Good) i I 1. --.1--1 - � 1- -.1 --- ­­ - 2,600 ' OOA � I . , -1--_-..-- � k --'- 0 : 'b r I ' - 77� Length . I � 1 I I . I Buildings' � - � I- I 1 . .11, 1-11.1-111-1.1-1- 40 -......1-1- ... - .... � ...... i Open Space (Good) � ­­i�6 --- ��,_­­.__. 1-11 ­­­­­ I..'��.-�---.�--.-.��..�"..��'. . ,84 , 0% a 0 1 ; I - _1-1- C _­_ I,---"- -1 I- ; 74 - .. � I � i I ;, 1 3 Ac, Lots or Twnhornes ��% lmp� . � I . � � � : I . I-- I-— � . .1 ­ -111--...."'. ­ �� .. .. ........ ­ ... I --- ­­­ -1 ­.- ­­­ - ------ - - - ----1_1_._-1-_-_ -111 ,-,I - - - - -A;ea� . I 0 11 1. -11.1-1 ­ ­­­ 41 - � I .1.1. I I-- __ . : � On--3ito Woods (Good) � __­ -..-:....._-.11-- I 29, 1 702 . I 0% , I ;, I ..... ._ , ­ 0 ­ �­­,­ i - ­ ... 0 .... � ... ... - : .... 11-1-1.-....' � 70 . 'Actively -grazed pa�i I Area ) ; : � ;­­.­ ... ­­­ : I 1 � --.....1- � . . I 4� , ­_ I .1. I— 1. I ". -1. ­. ­ 11-_--1-- I -1 ... -rf,M � 1 ­­­ __ ­__ J "-'- b- � ..��__ I i . . iyards-an.d cultivated - __ ___.- �:i_ ------ XP,P8 = ____ - � ..... _ - .. .... I . - __ _ . , , _ ___:,X 0,98- = _. ._ . ... .... ..... __, ___ - - ----- ----- .__ __ __ - - - , _ , " - I � � - , . . - ­­ ­ I 11�� 443 I'll 11 11, __ I _,_­ !�f,,� -1-11-1. _�­111­ I 1 00% � "'d, - _­ -, . -1 ... 1-16 ­_ - -- --- -- -1 I 1--l-I f 70 � I . ! Adive crop land Area � a .Area... ­. -1 11 . .. I . .__ . � . I ... 11 ­,��­1111_ - I . 411 I . , -1111104r1.1.1-1- . � ... li6,1�Ifl li-.1. - I..... -.1. ­_­­ ........... a I 0% j � I - I ". - 1-1.1111 .. ..... .. _ ........ ­­ , ­­-, ------ q 0 . t - �,,�..."�",.,,��,,-,�,�,---,�, � ­­ ­.­;­­_____._ G 1 74 ­.­ ­,­ ­­­_ I �­­.­ -­ _­... , . I � I i . � I I I . i � X O�25 = X 0,25 = I . 1 --------- ,,.,,..--.,-.-,.-..,,.,,,._,,.,;,,,,_.,,,.,,,,,,,..r... I � 1, - .1 - -.11 I 1. .1 � -1-11- � � 1 .. .... I - � ....... __ .. ... ­­­­ .... -_.-11-.- ------ - 1._._-:1---; -1 � I I.. ­.. 11. ­­ � Other Impervious Areas Area Area 2 Am 3 1 Area I Area 2 Area 3 - � . � . 1.11 .1 : : ",'�­­­­ .__ 917461 � 1000A 1 10,461 C I � 98 � :� I—. ­­ ... � � - I _...­­­._..­­__ - ­ - - -i-..., - .. .... - . 11 11- Drainage Area Design summary . , 11 4 I :1 . I ; I � I , . � : � . . I I . . � I . � . . .. ..... . -1 ...._........, .... _,"''..- _ 1. __._ _ __1 . .. ... � � 'I _m, -p,,e- ... -.111--l....- 11 ..... I.., ...... _�.,___­ ........... � . � 0: , I ­­­ 1i I : 1,229,78Tsf or: I 28.ZAc, i rM ou, � . s"bo-4ir, �­___.-OW TOTAL IMPERVIOUS = 6.18 AC � i.6.1% I - .1 - I : ; On-site Total - t : I_.._____­­.­ ....... ____-1-- - o ­­��fi'.Ifd sf or: � - i 7A � Ac. � - ­­ ......... ... , i __ - - - -1 ... I --------- ­­­.- ­.. 1(pre) I(Post) .-I... 1- ..­ ....... � .... .. ­­_. ... ­­ ... 11. ---.1- ..... 1111 . Total =� i 111, -11..----.., 1.11 --- I...��l,"�.1-I..'�1.1.11�l-.,�.11-:1-1�-�..�,�",-...".�.11��,.��,�1.11.1�.-.I 1,540,9WIsf or: 35,4Aic, � --- 11 t sqjz V ; iR!v" ­ - ................ . - .- 1. I.. 11.11 1. � � 1-11111-1. I 1.1-.111-1. 1 ; Weighted GN = � - I.F& _­ 1-1 1, ­­­­ 7 � I ­ I : : I ­--_­.­ --- ----- I � ------ ­ ........ � I ... ............ ...... � ; i ; 1 0,18 I 99,6, - ------ ----__--_._1 ­_­ Te Summary (TR.65 Method) SFeit_Pf0w- Shallow Conc. Flow Channet/Pipe Row Total Time New Develo rit #!p!�"�ppment Arear, existing Impervioustover - 20% - -.11 -­ - ____)"_�� ...... _ __ ­ --- ,", __ , -i---i -1-1-1 ...-I-111-1 ,.-Ill 1-1 1_11 � ____ ---- _ __ - � - - _ - _. - - Length 00 100 Length t1t) 1.715 L'oNth (ft)l M � r �1111 5 � : I ': I Jpre * I (P e) � L e i tpo ; i ii�� : RR % RR Area Type skl . � ........ _1111_1­1�_­ ------ -_'-_--1-_1111- _ ... .. ; ___ 1.1-11-11111111 ­­­ __ ..... __­­__­._._­.­ .... . ...... .. -1 I............- 1.1-1 ­­: I .......... ­.I_1­1­__­­­­­� . . - 10% Slope - 5.0% -__--1.--- - t I 6� -26%i Development Am � 0,70 �� 1,00: 20% *i 023 I 14,251 11,29 � -2,9 , , I � 1-11.1, 1.1--.--�-,-,.�,-,,---,...,-.----'N--.-''-�--�-�'..,-,,,.-��---. , -I'--_ " I ---- I ..... -1 .... ___,_____ .1-1-11-11. ­ _--s-11ne 2 -yr Rain (in) 4.0 Surface - Th"Itimebasedonan Unpawd - - -- - ---- -- - ; ___ . ....... -4 ... . ................ . : i : � ! " - -6, I � 1.00 I , 0%, 0,05 I 1,55 I 5A64 I 4, 73W OnWIng Water Watersheds � � , ! I -1- � 1- � ............ . � . ... -.1-111- ­­ __ ___,''. _. �­ -'----- I,Ianninjs N ayrs - 1'�, ----.,�­_-r-.. �, I - . I ....... 1_----- ... --.__-._1.____._ __ .... �.,-.--.--�-.�-,�,.�..�-.----,�v 1 _ - � ,��,��-.-�.---"".�"..,.".��I � � - ----- z 1140 - IM; IV 0,06: 2- ' 6A51 4, 1 68%� Other Rural Land � ; � � I ......-.1111.., I w : r -------- ­­ � - -------- ---- ­­­-­­­._­ --------- _________­ ..... - --- -_-._1--_- 111.111.11 _ ­ ��,L­.­.­.­ - _ .., ,.. - ___ _-0.24 ­_ Tc (min.) 3,33 To (miss_) 7,92 - - To I 116's I min, values 11 . Shallow Cone. Flo_w .11 I 1. 1 .1 1, I 411 - --. - ......­, 1 11.I1 ov_e. ­___­­­_­_ 11--- -1 1-11.-11 r.,, >-- 20- %11) r-­Delo­�p.! m­­en...t.. A.. r-e-' a o._u1_s.,-.. ... I... I ....11......11 ___­_­ 5,0% -._1 ........ ....... ­ 11 .1......-1-1.........-111. -1-..--"�,�-.-,�-----,.-�----"-� ....1 ....1.,.`.1 �- - �Slo c f Im) I (pT!-k(pp)_ .�sJ1­1.RR 1i­111%-RR-;AreaTyp.,. . I1— . , ..:.I � 11 __.-... Surface np*d 11..11 ..1111._. . _- ", a_ __ 1--- 0,70 � 0.J�6: OM 1A25I 11,29! -1 54i 44W Development Area ...­. .... 1 -1 " _ _ --..- . - .1 1 . _ 11.. 11 � I... I : ". , � � .... , .� .......­ ­ -"_-1-____. .... ...__ _ ... ..-----R _-----1... 11,-1.1.6- ---I— _---._-----._1__ I : 0.8- 0W 0.05 1,55 5,64 ! 4,33 � 77%Drinking Wateref Watersheds .- ­... Tc (min,) L 73 _._...._._. -..11111..1..Unth(ft ... ­..­.­.....­�Ir 12.;:1 _r'�� . .,.. -_..11 - .I -1, ­R­e­develop­1me1n1­1t -(F ..1*. .- .I- .. --j 1 - .".",­, .-,. a �G.E ��. 0 06; ­_Z06��i. ..4X7 72%Oth­r Rural Land ­e­xi­sU...ng....i.r..n.­p­�e­_r­A�I, ­ ­_c_- . . Traff trimlig'amer-tai�7-mii-relM!,- ;��� L Short Version BMP Computations For Worksheets 2 -6 TR -55 Sub -area Tabulation Albemarle County Water Protection Ordinance. Modified Simple Method ­ - ..­­ - Plan: Belvedere Phase I Water Resources Area: Development Area - ...... . . ­­­ ........ � ......... . . -1. .... I .. - . � Development . 1. 11 AREA # DESCRIPTION SQ. FT. % IMP EQUIV.IMP. SOILGRP-CN 13.79 8.49 L storm pollutant export in pounds, L=[P(Pj)Rv1I2Jt0(A)2.72J 1 Existing Building 23965 100% 23965 C 98 2 Open Space (Good) 14781 0% 0 C - 74 3 _ Pavement 107375 100% 107375 C 98 4 Existing Building 11954 100% 11954 C - 98 5 1 Open Space (Good) 5511 0% 0 C 74 6 Open Space (Good) 4519 0% 0 C 74 7 _ Existing Building 3476 100% 3476 C 98 _ - 8 Open Space (Good) 11924 0% 0 C 74 9 Existing Railroad (Industrial) 17103 72% 12314 C 91 1 10 Existing Railroad (industrial) 9107 , 72% 6557 B 88 11 Open Space (Good) 62329 0% 0 B 61 12 Open Space (Good) 1644943 0% 0 C 74 13 Existing Pavement 76969 100% 76969 C 98 14 - Open Space (Good) 121116 0% 0 C 74 15 _ Existing Building 3259 100% 3259 C 98 16 - Existing Building 5478 100% 5478 C - 98 17 Existing Building 3277 100% 3277 C 98 18 - Pavement 5887 100% 5887 C 98 19 - Existing Building 3809 100% 3809 C 98 20 - Existing Building 4442 100% 4442 C 98 21 - Existing Building 1919 100% 1919 C 98 22 Existing Building 1983 100% 1983 C 98 23Pavement - 4492 100% 4492 C 98 24-I Existing Building i 4831 100% 4831 C 98 25 Existing Building 1 2479 100% 2479 C 98 26 Existing Building z 674 C 98 27 -674100% Existing Building Lii LU C 98 28 Existing Building 4064 1 100% 4064 C 98 29 - Existing Building 4125 100% 4125 C 98 30 Pavement 9457 100% 9457 C 98 31 Open Space (Good) 396823 0% 0 C 74 32 Existing Building 675 100% 675 C - 98 33 - Open Space (Good) 16481 0% 0 B 61 34 Open Space (Good) 204021 0% 0 - C 74 35 Open Space (Good) 89764 0% 0 C 74 36 Pavement 54231 100% 54231 C 98 37 Sidewalk 10333 100% 10333 C 98 38 Open Space (Good) 8794 0% 0 C 74 39 - Proposed Development 273556 0% 0 C 90 40 Pond Surface - 24486 - 0% 0 C 98 41 Pond Surface 2054 100% 2054 B -98 42 Open Space (Good) 8197 - 0% 0 B 61 43 open space (Good) 51652 0% 0 C1 74 44 - Open Space (Good) 16211 0% I 0 C 74 45 Existing Buildings - 10461 , 100% 1 10461 C 1 98 Drainage Area Design Summary (s -i -I Off-site Total= 1403780 sf 32.2 Ac. On-site Total = 439937 sf - 10.1 Ac. - Total Drainage Area = 1843717 sf 42.3 Ac. - Weighted CN = 81 sf - Total Impervious Cover= 269388 sf 61%, 1 Tc Summary (TR -55 Method) I Flow Shallow Conc. Flow Channel/Pipe Flow Total Time -Sheet Length (ft.) 100 Length (ft.) 1715 Length Slope 10% Slope 5.0% Travel time based on an ave. velocity of 4 fps. - - 2 -yr Rain (in) 4.0 Surface unpaved ""' " '" - Manning'' g" =sN 0.24 PM'a',, ' Tc (min.) .) Tc (min.) 3.33 Tc (min.) 7.92 Tc (min.) 1 3.5 14.8 - L Short Version BMP Computations For Worksheets 2 -6 ­­ Albemarle County Water Protection Ordinance. Modified Simple Method ­ - ..­­ - Plan: Belvedere Phase I Water Resources Area: Development Area - ...... . . ­­­ ........ � ......... . . -1. .... I .. - . � Development . 1. 11 en 'Prepa r: Eric Anderson, Err Date, 15 -Feta -07 , ..... I-- . .................... . ....... - .... � --- � .... I .... . ......... � ... 1- ........... I— ------- � ...... ­­ ­_ __� ..... .... � Project Drainage Area Designation SWM Favi #1 8 Project ­ ...... r-_- - 1, 13.79 8.49 L storm pollutant export in pounds, L=[P(Pj)Rv1I2Jt0(A)2.72J A. MABEE RV mean runoff coefficient, Rv =x3,05 + 0,009(Q POUNDS Pi small storm correction factor, 0.9 REMOVED I percent imper4ousness 6.90 P annual lamcipitation, 43!'in Albemarle C. KOTARSKI A project area in acres in subject drainage area, 4- - -, � - I . 7 Ii. I - I SCALE __ _­ -11, - "I I I - - 0 pollutant concentration, rI or ppm target phosphorus N/A f factor applied to RR V requited treatment miume, in cy, 0.5" over imperv. area = A(I)43560(0,5f12)127 RR required remowl , L(Post) - f x L(Pre) %RR remoolefficiency , RRIML(post) Impervious Cover Computation (values in feet square feet) 711-1- -1.-__.11_..--__- "'. , , - .. ... .... -._-_.__,1_-_.___ ------- 1- - I ... ­_­ --1 -11 I. . - - - I ­­ 11 ..... I., ........ ----1___.-- 1-1....'.....-, _-.1..­­ :Area ; - I � I Iftemp 1-11 ­­­ I I I ....... . ... ... . -.-I..... I—— ­_ ___.-I . .. .... ­__ ------------- ........ ..- ­­­___ ----- __ __ _ _. - ------ -.1---l", ... .. .. . -1 I 11 I I I � ­­­ .. ..... '­­­.- I-, ;Area past-devel,oprnent -Area . ,pre-dovelopment ........_,_ - - .. . -­­-_-­.­­ ..... .. ­­­­ ........ . ­­_­.­.­, � ... .......... ­­ . ­­.. � ­-,� ­.... ... � ... I... ­ -- - � .. . . ........... � ...... .. . _ � ...... � ... � _'....., If Paved Length Width subtotal : . Length Width subtotal : I- - . ..... .... .. ... -1__..1_-.._,_ ------ ... ... ­­_.. I I . ,. .. .. . . I .1I 111.-1111 ''_ - i;. l 4. .:1:11:: 1 I., �I.11... I -11--,I... _. II v Pavement II -� 69,:302 ____._______ --1- -. ..-- orivewayr Length Width nosubtotal Len gh Widthsubtotal 1 -.---i-1-1. -- 1111_ _ --1.-I—, 1. 1­m.,e - .11 1. ,I .. _-- ---,.,__- ­a andwalks I ; . 1n. -- . . . ;......._._._---� -. 1-: --. ; Sic; e.i 9; 1 2,12 , ,---I r - '-__ -id._ __... .....I. � 0a 66A4i Area 2 k 3 Area 4. A" I Am 2 Area 3 Are4 �. ' 1 .I I_1_-_---_ _­_.. areas a 2 subtotal� Are.a I (Gravel AreaI Area ...1 - . I I I ­......5�.­ - � x 0,70 1x11- -101 1I-1'1 _ I 1.-.- pI, . 1s1.1,1u.11. ­b­to11­t.a1l -_---------- --1- -- _-_I............... ..­­....­rA1­r1e1.a ,21" ,".. 1:... l0l1_- -_-'I istructures Area M subtotal � Ano, subtotal , 111,..1. ------­ 11-1m- .111 .1111.­ "..i. I � �. I ­­­­_­_­­ ......... I ctiwly-grazed pasture & Area I . � I— ­­.... ........... I. Area ;�I.. J ,yaid = , turf x- 00 _- x.-.. ­­ .�.I -­ ­­a­r­x­c1u_fte1d­. -s -, , '8 -- ;Active crop land Area ;(sea .,1.3'-.1 ,_M_ _ i . .--.8._ --=- I------ i xO..,..2.­5­­= ..0.-. 5 X� -1- ­.­­­ ­­ _­­ I­....� ­. .. ..­ ­__ ­___.... 1 I.2- 0ther Impervious Ami Area I Area 2 Area 3 Area I Area 2 Area 3 I i --. .. 11. 11I 1-111- . .:,! I I I ; . I � �, I ; . �11­1':­: ­-._­­­_­ _.- ­­ ; ... � ......... �.,­­,, ". , ­­ � _'. A I - I - � I 1-11- - I I . 1. -.1 � %­ ,. , ,-. _ ­ I—- -11 _--1_--__1-----1 11 -1111..., . ; ; I Imperviouscover1�f��jl : � , , ........ I ' IA�l < 20%, NO I'll 1 llpoAi WATER � - . ............ � � ..... . ... � 1 Rv(post)-..._.._'1`___.. , QUALITY ! .,I F- 6J I 125.7, 1-11-11 --- � ........ 1.�'11.1­111_.__� . REQUIRED existinger evelopmen­t x oDevelopmentim­.-p. e- w-- e-�-- v­_F­.o�­ r..�.c,. o I(pom .i­,s �II­. C f I (Pre)Rv­pre� Qpre):(pod))­RR / RR .. 1...-e...n.. .. Type A---r--e ,..�. ­p_­m.­A-r�-.e-.-..-.-.a-. -­s-_,i_L.i -t ­�1( .-e-iIL---l-_. ­.­. 070 100 M% 023 1596 Iiit�.I5 16 Itopmni Areae ..-2,P1105-­A1I.1) I .lN._-.1._.._1_ -... o 100lr1/0.051.73 6.W, �1�1 % Drinking Water Watersheds � .i�v: ,ng -­---�e..- .- ,­--- . 11-d�­`, ...r.v..i..o...I..u...s ...1. .a.. . . .- ..1 1.1.. ...--1.I-- 1 . .. 0.40 ; IM;M 2.34 7.8 ; 655 � 70Other Rural Land- 1 I .,D_ _--...., - .---.1---. 1.-1... ...I—.1--111.. ` min, values Redevelopment (For Development Areas, existing impervious cover > 20%) Redevelopment Development: ­ existing impervious -, - - -- - - - - __ � ... - � ...... ..... . . . - .. �. - I .11 I., 1-11 ..... � ; C f � I (pre)' 1 Rv(pre) � L(pre) i : RR % RR : Area Type I . J _W!o4) 'j _ _ - 111. 1­­­­i�... "I"..., ... .... ­,­­ , ­­-,Ii_­___­_____i____ .... ...... - - ­­­ -.1- .4��­ -.1. i � 0.90 'I 2(r/o 1 OZ� 4 115M 1 13M ; -0,56 �� ; Development Area t ., I 1 ! i � ; I ; �­­­­­­ "' - �L ------11 - I— 11-1 ­ li-1,11-1. ­­­ .1.1 .. ,-.""...-""�,."""-,-.�,�-.�� ... ­­ ­­­ ..- 11 � 1 0,351 0,85; 0%; 0�6�`­­­,I*,b­7 "" i�9­0_­­­ ��4� � � * I � : . . 79%1 Drinking Water Watersheds , I - C3f­­­ ' '- La - nd - - ' - __ V. . _-11___11_-._- _­_ ...... --�.�",,,�]ijd 'I-._,- " 1��j4' 1 ­ h - a � T, Rural i 40 ;' 0.85 � 1%, OM 1: 2-34 � 7,88 �i � � I : I z � : - &4ffij kTJTJX'J JJ§2UU38jfflH= In ilk YAJ, - . . lk4 STORMWATER QUANTITY THIS PLAN AMENDMENT IS TO ADRESS ADDITIONAL IMPERVIOUS AREA DRAINING TO THE STORM POND ORIGINALLY DESIGNED UNDER WPO 2006-00048. THE EXISTING POND IS MORE THAN ADEQUATE TO HANDLE THE INCREASED FLOWS GENERATED BY THE ADDITIONAL IMPERVIOUS AREA IN THIS AMENDMEND (4.14 AC). THE POND REDUCES THE POST DEVELOPED 2YR AND 10 YR 24 HOUR STORMS TO BE LESS THAN THE PREDEVELOPED CONDITION. SUMMARY FROM SHEET C4.0 PRE -DEVELOPED FLOW: 2 YR = 74.94 CFS 10 YR = 146.75 CFS ShortVersion SMP Computations For Worksheets 2 -6 ­­ Albemarle County Water Protection Ordinance: Modified Simple Method ­ - ..­­ - Plan : selvedem Phase I Water Resources Area Development Area .1 ..... ­­ - I ­....... 1. .., . .... . I .... I—— - . _1 ­ I - � , - .. - 1. ­ ".... I . 1. - I I - ... ­ � -... � ... . . . I...." I ­__ Pre area: Amy Seipp, PE �. .. .­ - paten � -11, 1.4-S1cp4)$.1- I.. � - -1 ... ­ .. .. ...... 1111 .. .... ­ �.. 1. ­ I ­ 1. _ 11 � - Project Drainage Area Designation -SWM Fac.4itly-A3 -1 I .... .. ..". . ... - � - � I .. ­ ".. 13.79 8.49 L. storm pollutant export in pounds, L = [P(PI)RWI21 [ C(A)2,721 A. MABEE RV mean runoff coefficient, Rv = 0.05 + UWO POUNDS F11 small storm conection factor, 0.9 REMOVED I percent impervousness 6.90 F annual precipitation, 43' in Albemarle C. KOTARSKI ___, � , ., , l- 1111 = i A project area in acres in subject drainage area, A 4AG � . ' -1 - SCALE C, pollutant concertration, mg/I or ppm target phosphorus N/A I factor applied to RR �r mquired treatment %olume in cy, 0,5'overimpm. area = A(Q43W0oV12)/27 RR required removal, L(post) - f x L(pre) %RR removal efficiency , RRIML(post) I impervious Cover Computatilaln-_(y.l!gis.Iln-fleet.9 square lei , , :Area ; - I � I iftem .."I., -..._.-1-__- ­­ .. .1 - 1­11­1­1_j�6�1_ � 1 - 11 . � :11'.. - _­­ 11.1 ... - ­­­­ ­ I.". I - - I I-- ­­­. --1--1,11-.1-111111-11 IF re -development ;Area ;post -development , . I.- - - I ­­ ­­ . , , I ; �.. I ­ ­­ -11: .... ..... ..... .. - L , e � V - h .... ­­ - W -- _1 _1- - __-, . ­. .. " _ 11 4i� � ----_._,.____1_ ­Le ­­ h I ... I— Wi . dth ___. s . ub . toi -, I ___ , �- I - I, -111-1-- : idth - - . 1. s� ibt . ota I ; -1- � -1-1-1 I _­­ 1--l-I 11.1 I . � I : I . : . � p . I � . . . I � . i : I I - - I ; � � .., - ... .... . .. im. .­­­__­_­ -.-, ­ ... I .... ­ __ 1.11 . I . -1 15.72�1V,:I�. . I 157,21-I.9- __--I. ....... ...- ­Len­­-Widh- 1 1-11.- 1 .. ..,-I. I'�....----...--"�,.''--..-.,. -. ...-1 1111 1111_ . . _.�Roadways Ehi,,�Y, Length Width m i . Igih tno, subtotal .1 1 , : ..: . . I .... - . . .. I 11 11 . .11- Ii i and walks ; I 1-� 1I I I � I . . � I I : '..I . 11. .1 ...... _ - : ... . . ......1. .1. ...... ­­ ''.. . ­ . � Sideviaii I 5-5 I .8 .. 1 5 1 55M1 :1111 - -'e" f , " , "-­ * , 0ariirg Lots Area A2Area Area 4Area Asea A 3 Area 4 . -- -.1_11I 1 1, .. ----',-1.--'- .....­­ ­- - I : 1--. ..-. 1 1 .1 .11- 1111. .111111..11 .. .. ..-...--1-1--- I.. .—��1 0 -...11l -i ''' ' -` ' '11_.11,1111.._ ". --I....11,--11 ­... 1. . 1111...;..- -,- ' '- 4­ia� Grawl areas Area iAra2 iubiaal Area 1 j $6oi 1 ... _ I 1.-.- pI, . ._--11-.I!1_ 1:I � I 1- - -1-11.-- -1....-11............ .�..­­­-,.,.,_1___­ . x 0.0; ;X 0.70 = : , 1.. 11' .. 1­1_� . 1 - . 'i., 1 , ... 5_1=turesArea M subtotal AreaW, subtotal '. . . .: . . I ;�I.. . I ­­. I -1 I I'll. ­­ I 1. I I . I . . .1- 1. 1. � . � I . I . I Buildinqs� 1,643 :.............. : I i-- ­- "."'. . � � q ; 11--r, - I � ­ - - � .1 I - 1. - , : � 1 . : , ;18 Ac. Ws orTdwnf*meM19 imp) 200,223 .1--. .,1.3'-.1 ,_M_ _ i _­111.1111-­__. Actively-g-azed pasture & Area . Area ,11- - II .. 11---I il"..-­­­ yatft and cultivated turf x OM = x 0,w ,11-_--_1---1 .- _._.1 - - ..,.... 1-1-. 1-_l..--,�-�"--",.-".-",- ��..--. .."..�."��"... ­­., --,..'.1_"-.-11'.. Acfivcrop land Area Area . 0" 0 = x025= x _25 . ­ . � �. I ... .. t _ __ - ­ . _ ­' -_--__ -—..- - --....I., -1 - - Other Impervious Areas m I Area 2 Area 3 Area I Area 2 Area 3 ... . ;, � . . .,-­ I_ . 111:.......1 .­­ .......,___,,­, ­­­­ ­­."... .1.1-- -I.- . ... :_-._.,.._.;1..11 : -..-,.,-,-I I Impervious Cover 0% <_....... ...1 5 . ....W I-l- ­ ..'l----.. _.1. Rpm) I(pom . ! , Rv(post) . __ .... ................. 1 . 0 - 532,54.2 es � - I 1. I ­ - I 1; eeaov1 NDevelopment..� -9 11. ... ... ... .- .! I.U...n.I.g---im.--p� e�, 1a. I - .y..p...e ­ ­.­. r- v.fous. * ­-.x..Ii..s,1 v1e;­l­pIm­ (­F.o­r_ n- ­­- - 1.-.1F, rIe., C I I I (pre) R4M) Llpie) L(post) AiAreaType :.I, ,c.. --­eIrI _%RR .......­.­1111... -­.­...... .-­ 6,t#.w z 0'"; W.�I; 46.16� 27 .83 � � Dwtopment Area .1.e.."..I �1l.-o1�11p -t ..e.­e­ ­D-1I -1--- . ----- ­11-''-'aerateseds0.35 r 1.00 i 0% 0,05 2,21: 24�0�� �fi�D-6nWngW -I1 .m..entA; ._i4 - --- i-......._-_- I—1. I1I..."..I—­ ; � 11 - -11 -_."..---1..I..-.�. .. __-1.- 0A0 I.OD; 1W O,W; 2,9 2Z52. . i : "her Rural Land -. ............. .--.....I �,l.-I.",.",-..-,,,:--11 �11.I . ­ ­_­.­­_.... ..--.�.-e � , ­­ --_.....___-.1 - ......... man. -01mm Redevelopment (For Deyelplo ntj"as, exisfing impervious cover 20%) 1 1. I 1111_.._ -1- - ... 1 �� --.-I-1 - � .1 . ­­­­ � .... ­­ -1 _ .... - .... .... _.___.---4#t-- __i-._...11.___._ -1 I., I ............. i"... 61. 1. . . I % , Area � '.(.(Pre) (pre)* � Rv(pT) ' L(pre) I L(post) � RR � ­�� - - - -.11- -1.1 - ­­­. ­: � : _ .... ___;__ ..... ...... .._.I ... " _ .. ....... __i§61;, 1--1111 I I", . w . . � ; ': �A ... .. . * 6,23 � 20,33 � 48.16; 29. � 62%' ,, Demlopment Area � 06,- ­0�,9­0­ ... . ... 7 . .-III.-l- �_ � I—- 1. ­11- __._­­­­..:.Il��i � ! r , ___ - - .. 111.. 1.1-1.1-1 ".. I.. I ­ I- I I-— _ - . ....... ...... � ..... . - ____ ... ­_ -11, -11.1-1--11-1 . 0,35 i O�W: W1o; 0.05 2.21 1 24,08, 22.20 � 52%'s riking Water Watersheds I I I . -...1____ - .. � ._.� _.-----11__.-...-- -1-1-1-1-- .1, I a I . � � : . 06 2,98 �; 27,52 � 24.99; 91%: Other Rural Land V,io. ' 6._i�lS` * _i�4� ­ -6 F * __ - _' . � .. I , I 1. ­ . ....... ­­ �I ­. ­...". � I --- - .... I ... ­.... ­ ...... -1--l- 1- ­- . POST DEVELOPED FLOW (ROUTED THOUGH FACILITY 1A): 2 YR = 34.97 CFS 10 YR = 43.05 CFS STORMWATER QUALITY WATER QUALITY REQUIREMENTS ARE BEING MET BY UTILITIZING THE EXISTING POND AS A LEVEL 11 RETENTION BASIN, AND THE PURCHASE OF NUTRIENT CREDITS. NO MODIFICATIONS TO THE POND ARE REQUIRED TO MET THE RETENTION BASIN 11 SIZING CALCULATIONS UNDER THE TYPE IIC DESIGN CRITERIA. RETENTION BASIN 11 SIZING CALCULATIONS REQUIRED VOLUME = 4 X WATER QUALITY VOLUME WATER QUALITY VOLUME = 0.50 IN X IMP COVER REQUIRED VOLUME = (4)(269388SF X 0.51N/121N) = 44,898 CF PROVIDED VOLUME = 84,872 CF @ ELEV = 395.00FT Short Version BMP Computations For Worksheets 2 - 6 Albemarle County Water Protection Ordinance. Modified Simple Method Plan: Behedere Phase I Water Resources Area: Development Am I I ­ .. . ---11 ­_ 1- --1 11, .... ­__ ... I � -...-,. .I I - - Development ..... ­­ IPrepa-rer:.. ,_. _A11.mI...."'. PE . .D_.­at..e.-:.­ ­1.._Po.1p. 6-- - - I----. 1111_.... ­ - ..­­ - Project Drainage Area Designation ­SWM­FaclI!!y1#,5­ - 11 11 ­­­ 1. 07127118 L storm pollutant export in pounds, L=lP(JPJ)RWI21JC_(A)2.72j I -post RR (1 -post - Lpre) Rv mean runoff coeifficlent, Fav tt 0,05 + 0,009(9 13.79 8.49 Pi small storm correction factor, 0.9 A. MABEE 1 pement Imperviousness POUNDS P annual preciPtlatioti, 43' in Albemarle REMOVED I A project area in acres in subject drainage area, : A= 10-2: 6.90 C pollutant concentration, migA or ppm target phosphorus C. KOTARSKI I factor applied to RR SCALE V required treatment %olume In cy, 0.v` over imperv. area = A(1)435WO,5/12)127 N/A RR required removal , LOost) - f X L(pm) %RR removal iefficiemy, RR1041ILfpoi Impervious Cover Computation (values in feet& square feeq._.,__ _______ , _....._.__.___.. _...", -1-T ._ .. ____ .... 11 ... ...... - ____ ....... ..... .""-�"".,.".,..""",.-,., ____ Item - -1-1.1. . - I..., . I 1, .1, ,.-.111�1 "...",.,''.--.11."....-Ir...�--.1111--ll-__ 11..1-11 1-11 ...... _ ._. - I—. . I- ..... ... . .. .. . � ..... _ :pre -development -Area �pilopment � .. . % .... _._._.._11-1.1.__ ­-.­­­­ _,_­.,_. 1.1-1 ­­­­ ­ :Area ; - I � I - 11_-1 .,-.,-.-�-111-1--.""-,1,..�..�----".,-,.------ __.._1._..1.___,_ ....... . Paved Length Width subtotal I : Length Width subtotal . ­­_ 11 ------ ­­­.. � ----- --------- -...1i I - I 1- 1- _. -1 ­: ... 11 ­ _­ ­­_­ - ; ; 4 . ; . I I I.­. ..- I­��­.­..<:I ­ RIIO S ,707 w.,:��. . .i- -th ­­._..-...­ ,,1iL.I� .-"1.1....1._...�1.1.111 ,.,....1 �"," ,70_ I, . ......,.,.,..--.,. . _�_I-_.­. 1111...., 1111... 1111-111 - -„1:111. ,,.. ...� ifiv�hnosuM0taI Length M subtoal 1. . 1 1 ­ 1iI ,b�yS— ..-..---,- .."- 1111.:-, -­.­ _1111, ...-I-- 1- I._ and walks I - - '_.-..._-- .'. .11..-."4 ....­-"1.-. .._.­.!..._­­1I�i­.�i IiJ. ... I .­_­1.­­--­�-11.­------, .. ; < Sidmilks 7,5% ..: 27,585 _.:: 17­-..-1-11..-:-�I- .I.1 . .11...11_...L. -......... .---1-_1_ -11. ..... � ­­­­ _.­­_-e11...I111 -----1-. 1..1. .1 �lkIngLs Area I Area 2 Area 3 Area 4 ki 2 Area 3 A 4 . .1111..... 1 - . -1111.___'-1 -1111I.- � --1. -----.-.1....11 1--.L--1__--- . 1---I1- 11:,:.- --, -- -- -1I­-� , 1--_ Gaveareas Area I Area a 2 subtotal i 3 Area I Area 2 subtotal ----.-I _,­ _...� ..�... . 1111.; ; � -­ I _-- ­:__ 1-1-11.1- - - _1 - ---.-.-1-1- `74; O:x 0, 0 - x 0.70 ., .-I 11 �II ,_1111... ­� _.� -- �- ­. I -I-1II.. ­ I I ..,- . .1-. ..,­­ ­, - Structures Area no, subtotal : Areano,subtotal,1,,..-:I ..1�1.1..1.-1-..wI.. . - .."I'l-11.1 ­­;� ... 1-11-.1'.: .. . .... � '......, �; ; I I I . ! . Community Center (65% Mnp) 128,256' - - .... . I 1-1--.1- .1.1 �.. . . ­ I _.__ . _: , I I . � i I . � Ac. Lots or Townhornes (651A imp) : � � - ­ ­ I.R) - ­ 11�'�M7I 1-111-----.-- 11--.___1-_... .. . ... .. 1. y--- I 193,117 . ­ ".. � 11 11 ----1-_-1 1, I 111 ... I.I.-l- . .... ­_._.­_­­­ ... �.,11....,.�-�11--...,-111.1--�1-1--l�..'��.-I.11,�I Actwly-girazed pasture & Area : . Area I '. - _11.1-1-1- I I : '." � I I � Y and cultivated turf e� . . X 0.08 = � � 1 IxO.08= 1 . � ­­ I 11-1- ­­ -11-_--_.- 1-11 ­­­­ 1- --- __ ... ....... I - 1- . ......... 1. . -I:--..-- -.11-11 -1 - . -111.. I -­..­,.­­­-,. I - il 1-11-1- � . __ .... . .... ...'. .1 � -.11-1-1 ­1 AreArea Aictlw crop lam Area. 11 I � ..a., = 5 Ix02."1111� 21,5 II 1- 1 -1...1. � _ ,- ­'' _'­_­I'x - �-,��1� bt Impe4sAiesArea I1a2 Aa 3'Am .I1 i ­Area 3 11a- 1. -=1 11.1. 1.11-1----..11.-1 11. 1I I - I 1. I - 1.-.- 1-1Ai.'.."�.: , . 0" !F;I..Ir ... .�. - 1.'11 -11-1111 1--1---I—-...---- ---, _1--..-1.1.--....._-- --- - ..­......._. Impervious Cover M tI .� - ore) 1_­­1� (iI .. Rv(post) .1 V .­.­, � � .­­ 062),4327- New Development (For Development Areas, existing impervious -coyer <=,�Wl­ ­­­ -1-- � -.1 ­_­­­ � --- -- -- ­­ I - -- - , ­­ __ - - ---- --- - � J;­­­ - -- ­­­'. ­­.- � - ---- - ,---- '. _ __,,_,"- ,,.-.,, ­­­ _ 1, _­_(Pre)' C i f � I prey�;Rv�pre)--f Upre), ; � . . 4 1111 __ _ z I -1 -1 ­]­ ... . ... 1, .. . ............. � ------- - -- ­ ­ -----.,- --- 11 L. ____ - ----- 1­41�0 i­­.­��_i. -1 . . i '-" �6�-, , I 0.70 1.001 e 6�& i ; � 24,30 63W Development Area 7 . I1111._i � � ---- 1-11- .... ,il-I��_____'.., ____ __­ -1 1- ­ . . "'.-I .... � ....... ­­­­ ... .... ...... � ­­­.­ - ----- � , _­___i�' T - _iii'j5 Il 17.78 i i Drinking Water Wateisheds , 0,35 1,00 1; 0% � 0.05 � ; I . �� I r � , I I,— ... ­ .. ..... ... ............ .. �- � � " ­ - I I - ­­­ I - ­­ -1111.. . ­. z - -, �­ ----*"-- _­'__��A"'C 20.03 'i ! 16.46 i: , , -I b6"i " - , - f�6:, - ^ _O'Wo � Z I I": � Other Rural Land ; � ­­- ­­', - - . -1-1.11 - 11 I -1 I �. - I... 1. I - I ­­­­ I ----- - ­­�_, ' ­� ...1 1; ­ I -­ 11. -1-1 ­. -If 1- ... - ... ... . ­ ---- -_1 ... ____ ­_ ­­_ ___ _ ''....- min, values e o-�-.v--er � . , e�.-r� ..v�i._,- ..'­p.­.... ou.1.1�s-1. d-e p. De_.._._v.­.el_-_o. I pm�.A---.�-�t t-­. a­-­� i.,.s't,._.'m ­.�-.,.���.I—.-.e.-'.I - ....,­".__ .-.­..... I �-.,r* '. C I"Area Type..-.".-.._.. ......, f : I,(pT)----�OT).,_�(T; I ", l.- ....-.. ..- .-- ...--.- ...-...-....... ­. ­.. -11 ... ­-1c-�-- ..R­_­­­­%RR_i ,.._ _,_­)­1�. -- __bJ6.090200/,! 0,23' 14.40 38,70 25.74 67% Development Area ­.1...1. -­-------W ...e.. -,i"­-m." 1_1111,-,-.,:--­­­--------_­ .m.-- ­­ter Watersheds. . I L.-x....� ­v,.,, 035' 085� 005 1.57' i618,02a b�%Nnkig - ........... .1 .. .�- IRI. -_-_e- 1­>.,_2W­_­I. ­_ ..­_­ ­.(..F-o,.�.1r-"_- .'-­ 1.l -.o.` ­, ­-1e­1..1n.-­... � .._......en,1t__.�,.s.-_'"", ,..."..-I.." __11-1111 -- b.4&05I I�4O�06211 � 2211 : 2032i�Other Rural Land 1 - . ..... ... ...... 1- WATER QUALITY ANALYSIS DATE TOTAL PRE POST � W AREA IMPERVIOUS IMPERVIOUS 07127118 AREA AREA 1pre Lpre IpOst I -post RR (1 -post - Lpre) 10.1 Ac 0.00 Ac 6.18 Ac 20 5.30 61 13.79 8.49 AREA TO IMPERVIOUS A. MABEE TREATMENT AREA REMOVAL POUNDS Itreat Ltreat RATE REMOVED 10.1* 6.18 61 13.79 50% 6.90 Itreat = 6.18AC/10.1AC * 100 = 61 C. KOTARSKI Ltreat = [0.05+(0.009*61)]*10-1*2.28 = 13.79 SCALE POUNDS, REMOVED = 13.79 * 0.5 = 6.9 N/A *TREATMENT SYSTEM IS A RETENTION BASIN II TOTAL POUNDS REQUIRED TO BE REMOVED = 8,49 POUNDS TOTAL POUNDS REMOVED =6.90 POUNDS CREDITS REQUIRED TO BE PURCHASED = 1.59 POUNDS -1 I " - U j I r',�,'A�l -11M ig,� "'N,4� � , .f - "I ro ,I I A."'1� '. , I - V � "s A, � � I � I A, [ ! I I 'T I II -1, ,__� I4 ��L , �, ____�1+ ." , - - I I � I , 'O 1. � � - w . ,.�I I , V q I , �, , .� ( -, I � C,� I I "I � 11 , I .1, ,I, , I 1 �14 � I '�*'�. 11 , � . .. , I 0 I .Y,g Lic. N304Q2048507 � ,�,. 4_1 7 �Ip 1111-3/18 4,,-, , SA - , -"w ,�.';& - - 5, a K11WIN11, �_ - '37-n,@Tt .i��11. � � . -1- � - E DATE � > � W � :D 07127118 Cm Orn 0 r- , 2: DRAWN BY SHEET NO. A. MABEE M U DESIGNED BY Ln J. WILSON CHECKED BY C14 Ui Nr_ C. KOTARSKI 0 SCALE 0 N/A �0 0 0 E 6.9 LU •: U a) 3: I'-" LL :i:; 3: 0 0 LL L r� Lu 0 ru ,q C� M LU = Q_J I—, Ou 2! a- _J - 1i LU 0 CL > C:) r, 1 7- (A - o- fr) r,J LU 1;3- N Z_- L_ a) ria Cff 4 q- - l_ =) X U s W Lo (n LU 2� 9 6� n 04 :n 't U) X- 'N z: U IV 'D 0 M: Ln < > - C: Ln (.0 - 0 CY) � r14 > V) 4 LU Q) U) (f) " M Cl- -,I- 1-- 1-- z z 00 -1 CD LU Lii LU %.D 1-- 2: 7- 00 U U Vi 01- re � LU U-1 =) c- a- 0 o0 = LLI LLI 0 U) U) 0 > > C� LU LU = . cl� I I I I I- 0 LU 00 00 > LU _1 �� , Ill - = � , I -q M -1 U 0 N , < (s -i -I z Fn DATE � > � W � :D 07127118 0 r- , 2: DRAWN BY SHEET NO. A. MABEE 0 DESIGNED BY Ln J. WILSON CHECKED BY 00 C. KOTARSKI 0 SCALE 0 N/A 0 0 0 z -(a[) 0 ? to, =3 I. -I 0 C - - 'm 0(1) < > �2 '_ CU -C 3: D a- C(D L 1-4 2: �i 0- 144011op, 0 >1 = 2 LLJ (,) , R I ^ _0 (1) <ce -:, V) z C) 2 < R� z (O,) = 0 < C: - Q� W .= wNa. > un 20 >: �_ r'u- i- LU R z I= `o_ 0 -02 cl� U = = i I I UJ UO i� -0 L L 73 ' LA_ 0 -0 IK 2 (D I I I 0� %, cg , LU UJ V) W 0 co �Q co 0 > < C: L 0 546 _J M 46 E- ae� 10 , LU L) - - = a� 0 rn = 7N LJ.J o= LU G ,C 7 z In to 0 2- 2E 0- UJ 2i X W � W _J ,Z5 a- r- , 2: as - 5- i: 2'§ SHEET NO. 0- C� P-4 0) Ln .'n 'S 2 'n ca = (n 0 - X C a) 0 2 0) I = 0 'n 0 C: m ID � E ;,a- m cu 0 0 -0 6 -0 .0 7 C .11-0 5 JOB NO. 0 C: M 0 In . M U CUy) C: W 0 0 SHEET NO. ca �aC .2 C5. 0 E3(A 0) 0 -� -it-' - � =