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WPO201800077 Plan - VSMP 2022-07-14
OLD TRAIL VILLAGE -BLOCK 32 VIRGINIA STORMWATER MANAGEMENT (WPO) PLAN AMENDMENT 3 SITE DATA: TAX MAP PARCEL: 055E0-01-00-000A2 MARCH MOUNTAIN PROPERTIES LLC PARCEL AREA: 23.27 AC LIMITS OF DISTURBANCE: N/A - WITHIN APPROVED LIMITS OF WP0201800077 ZONING: NEIGHBORHOOD MODEL DISTRICT (NMD) OVERLAY DISTRICT: N/A MAGISTERIAL DISTRICT: WHITE HALL SOURCE OF BOUNDARY AND TOPOGRAPHY: BACKGROUND INFORMATION AND EXISTING CALCULATIONS SHOWN HEREIN WERE TAKEN FROM WP0201800077 AND SUB201800164 PLANS BY ROUDABUSH, GALE & ASSOCIATES, INC. AND APPROVED BY ALBEMARLE COUNTY ON 05/23/2019 AND 08/13/2019 RESPECTIVELY. TOPOGRAPHY WAS PROVIDED FROM ROUDABUSH AS -BUILT SURVEY FROM 2020. COUNTY OF ALBEMARLE Department of Community Development a,r , Construction Record Drawings (As -built) for VSMP The following is a list of information required on construction record drawings for stormwater facilities (reference Water Protection Ordinance 17-422). It is preferable that the construction record drawing be prepared by someone other than the designer. Please do not provide design drawings as construction record drawings. A. A signed and dated professional seal of the preparing engineer or surveyor. B. The name and address of the firm and individual preparing the drawings on the title sheet. C. The constructed location of all items associated with each facility, and the inspection records to verify proper dimensions, materials and installation. The items include, but are not limited to the following: 1. Inspection Records and photographs for pipe trenches and bedding, including underdrains. 2. Video Pipe Inspection for any pipes which are not accessible or viewable. 3. Updated Location with geo-coordinates of all facilities. 4. Verified Drainage Area maps for the drainage area treated, and for drainage to the facilities. 5. Current physical and topographic survey for all earthen structures. Ponds should include a survey of the pond bottom. Surveys should verify pond volumes are per design. Corrections may be required for alterations from the design. 6. Plants, location and type. 7. Plans and profiles for all culverts, Pipes, Risers, Weirs and Drainage Structures - Display the installed type of drainage structures, culvert/pipe size, weirs, materials, inlets or end treatment(s), inlet and outlet protection, alignment and invert elevations compared to design. 8. Computations: For significant deviations from design, provide sealed computations verifying that the as -built condition is equivalent or better than design. 9. Ditch Lines - Display the constructed location of all ditch lines and channels, including typical sections and linings. 10. Easements - Show all platted easements with dead book references labeled. Facilities and drainage must be within platted easements. Provide copies of recorded documents. 11. Guardrail, fences or other safety provisions - Display the constructed location of all safety provisions; fences, guardrail, including the type, length and applied end treatments, compared to design. 12. Material layers - biofilter media, stone layers, sand layers, keyways and cores must be verified as to material types and depths. Include inspection reports, boring or test pit reports and materials certifications. Biofilter media must be an approved state mix. 13. Access roads - show location of access roads, surface treatment, drainage, etc, as applicable. 14. Compaction reports are required to verify fill compaction in dams. 15. Manufacturers certifications for proprietary BMP's certifying proper installation and functioning. WP0201800077 COUNTY OF ALBEMARLE, VIRGINIA 04/05/2022 LAUREL HILLS -lam .tlo9 C R O Z E T Crozet Elementary CROSSING School0 HARD ACRES GRAYROCK a e..ams WAYLANDS GRANT 3 WAYLAND PARK Musictoday uxmroasaa nd C] eg'4 aF BARGAMIN PARK `, m CrozetG � SYon Hill Bre s- ` � Lrmam 6a➢Ra Hyland Group © 9 R E A '� 5 rba,r PAR E /ILLA G Claudius Crozet Park© c tl ,o \ a Crozet Park &Pool ardli s d' PARK VIEW PE Theno'dge at Old Trail V B R O O K W O O D Old Trail Gal( Club® a TRAILa W OLD WHITE OAKS 's � owners Stall roh 33 SITE The SummllQ ` NTAIN LOCATION Apartment Homes` ' QCmzet-Meadows i T FARMS � germK ' 5 / CO 9Pledmonl Banu l:: Chur,ri y,'bw`oW'-- Pro Re Nata erewec -Q Willow Egame�� ® RAYancey Lumber j M i I IS �� Corporation sa F O Western Albemarle 0 High School Goggle EST GLEN R r ow n svllle 'a xw MOUNTAIN VIEW BROWNSVILLE HEIGHTS EMERALD FOREST VICINITY MAP 111=10001 DEVELOPER: MARCH MOUNTAIN PROPERTIES LLC 1005 HEATHERCROFT CIRCLE SUITE 100 CROZET, VA 22932 CONTACT: DAVE BROCKMAN TELEPHONE: (702) 985-9088 EMAIL: DAVE@OLDTRAILVILLAGE.COM ENGINEER OF RECORD: TIMMONS GROUP 608 PRESTON AVENUE, SUITE 200 CHARLOTTESVILLE, VA 22903 CONTACT: JEREMY FOX, P.E. TELEPHONE: (434) 327-5382 EMAIL: JEREMY.FOX@TIMMONS.COM Sheet List Table Sheet Number Sheet Title CO.0 COVER C1.1 APPROVED BMP CONVERSION NOTES C1.2 APPROVED BMP CONVERSION PROFILE C2.0 STORMWATER MANAGEMENT NOTES & DETAILS C2.1 STORMWATER MANAGEMENT PLAN & CALCULATIONS NUMBER OF SHEETS = 5 AMENDMENT #3 NARRATIVE: PER APPROVED PLAN, WP0201800077 DATED 05/23/2019, A BIORETENTION FACILITY IN CONJUNCTION WITH AN EXTENDED DETENTION FACILITY WAS UTILIZED TO SATISFY WATER QUALITY AND WATER QUANTITY. IN THIS AMENDMENT, A GRASS CHANNEL WILL BE ADDED BETWEEN THE CURRENT PIPE OUTFALL AND PROPOSED BIORETENTION FACILITY. THE IMPLEMENTATION OF A GRASS CHANNEL PROVIDES ADDITIONAL TREATMENT AS WELL AS RUNOFF REDUCTION TO THE DOWNSTREAM BIOFILTER AND EXTENDED DETENTION. SUBSEQUENTLY, THE BIORETENTION FACILITY HAS DECREASED IN SIZE FROM THE ORIGINAL APPROVED PLAN WITH THIS DESIGN. THE 2-YEAR AND 10-YEAR STORMS HAVE BEEN ROUTED VIA THE NEW FACILITIES AND REMAIN IN COMPLIANCE WITH THE APPROVED PLAN. SEQUENCE OF CONSTRUCTION AND NOTES FOR PROPOSED AMENDMENT 1. CONTRACTOR SHALL VERIFY EXISTING SILT FENCE IS INTACT AND FULLY FUNCTIONAL PRIOR TO ANY SWM CONVERSION OPERATIONS. 2. CONTRACTOR SHALL INSTALL NEW SILT FENCE AS NEEDED TO ACHIEVE PROPER DOWNGRADIENT PROTECTION FROM SEDIMENT RUNOFF. 3. EXISTING RIP -RAP OUTLET PROTECTION AT THE PIPE OUTFALL UPSTREAM OF THE PROPOSED GRASS CHANNEL SHALL BE SALVAGED AND REUSED TO ACCOMMODATE THE NEWLY SHAPED OUTLET INTO THE GRASS CHANNEL. 4. GRASS CHANNEL SHOULD BE GRADED IN FROM THE EXISTING PIPE OUTFALL TO THE BIOFILTER FACILITY BASED ON DESIGN SECTION SHOWN HEREIN. 5. EXISTING AREA FOR THE BIOFILTER LOCATION SHALL BE EXCAVATED AND RESHAPED TO DESIGN GRADES SHOWN HEREON. 6. ALL ELEVATIONS AND INVERTS SHALL ADHERE TO THE PROPOSED DESIGN HEREIN TO ENSURE WATER QUALITY CALCULATIONS ARE MET. 7. UPON COMPLETION OF SWIM CONVERSION, THE SITE AREAS SHOULD BE SEEDED AND FULLY STABILIZED WITH GROUND COVER NOTED HEREON. SIGNATURE PANEL: APPROVAL DATE DEPARTMENT OF COMMUNITY DEVELOPMENT: ENGINEERING APPROVED by the Albemarle County Community Development Department Date 7714/22 File WP0201800077-amendment 3 VH,., n 0 Lf IEREMY L. FOX y Lie. No. 60786 0(V H / 22 r21 N Z 0 f LM H O d U IY It 0 0 Z U O Of w �_ a C) W UJ of (n N N w O N Q V DATE 04/05/2022 DRAWN BY J. FOX DESIGNED BY J. FOX CHECKED BY C. SHIFFLETT SCALE N.A. LU G z LU Q 0 a Z c� N > W M J > O ULv LU Om J Q J w O � Z LU r n U V Q J H� J LL H 0 J r•1 �J JOB NO. 47010 SHEET NO. C0.0 L S-1 EXISTING_ RETENTION FACILITY va OCR s+aPP - _ .. ! .. _ ... :._.:. _ PeiiamanceBased Water quality Calculation Procedure i sm-Artrs:z ErF (Iui, I,, ) = i[io S Alivitimi szi) I ... , i.. .. .. ! _ { 1�= . �... a% <,_... ,a% - - E D Jr 21 PURPOSES FROM APPROVED PLAN DATED 2019 m a Performance Based Water quality Calculation Procedure I oN�loek�rlNFo=a,a�,a�aE=i�n�,Lam) n�, _ .. -� ; PLpwIIb: ,M, ,� 1e% BY ROUDABUSH, GALE & ASSOC., INC. �:I v _ ... ._ .. , ,I ! I ____ _ ___ __ ___ L. ._.. .... .._ _-[_ A- .. J f Alaa,.,uc• � 83% W},trg" EPF _�_ re UI[ed Ilnatn rElNlVal ttl'LC1etlC ____ .�: _' �.. I _a �, �. q.... )�i .. _. -%... .._. ..._ -'.-_- ..._ _.._...._ _... _._Dam •: Y2`Feh-10 '. �44, ..a_ '--. - ...., .. .,. 'Proj3ct JxN-Bletn 3S Wfa026i8QDR1p.(@71MRPlrBEx iQeQDe6aniten) .. ,: !;':. ....... .. -.. _ ..r ..._ I -.. .- . r < . 'Lacailq•_N6errtarleGo- :'',. --• ,,�,. ;..- . .. ... .-- - .. {j 212212018 B:39, '., t� ` '= ' .. .. .. ... Y_...... _, __ I-__..,.L_. , � I�!A ,-..! _ r .. per yCBl) _ .- _...._ a gpRY'fennx..cNn: _ _-•---- -.. .RR___ hollntarnre�uoynl rerl'urmx!Y(2P^_ .-• - ---..---,-'--•• - ------- j anUXl10N3 Ivae, -'relabvepost-developffamtDWplwsphomisloadC.cnotion5-21 (Y�I�Ym) ' ' i , isuamnrycrfshoetiar2 odaxia: tnnncalanlatioa praccdl¢o 1hrv�.,i, WorkslN�l: I lhhe 1„N 0% >J.,r. ,0% J,�,.at: aYlta wu4e. w.wr� .x. yb w. LL in N Ui O m .-.;. ..'' ._...I ... .. ... .. ._, I - W orksheet No. , ... 1 I _ .. ..- ,. ... .. .. . r I ... .; .-. . I I , .. i ... .. IF.FF = �1.60 / &08 x100= , 32% •.. ; ; - - ! - I mas. aYtE- _ , _.ate �, A° -was 44* ,seas 1 � a N Q 0 � ,.. Oekertl]ine {he.appiwtile area and the st-de ,.. npervious cover] 1.-. __... -__-_ _ _._.. ...__:_ .. ___ _ _ _.�_ ._. y .. '. ... _ ,.. �_ ._. _..� _ ' _ _ _ _ _ _ _ .._ _, _ .-...... ! •_. ..-_. _ ..._...... tcdau„r. I va4w._ _.. , ." - -. .. .. -_ -; ' In'e9. ear III+• x -w• aa„ ,•a+. •+a- +t- - O • _ ♦��� tcalilemea A = 34236t6sf.a-_ 7.860 i•a•s __ '-.-_ _ C..I ---- .. ,' r-, ,_-------.__. -. _. _.- 1-_ -:._ ..._--..y'.. .. ... t .. 3._Select s & _ _ ... - . -. y _ ;, _.r ) Cnl'hStlle S-I48rld locate 0n JJ1e 31(0. _ _ .T _ CURRENTLY IN a , Drainage I wwe. yea. .tYYk- �+Illi!r� �aa40. �1ILI4� Z It .. L.. _ ...... .-._ ..-. t .. ..... ...... .._..... ... i �. : Ilrrpen,oua ( 'Area I k .,.. x w, Oka 0 ' ..:Foot-deveMpment impervboa coven ..... ........ - .. i..... ...... :........ ......... .. . .. . .. . .... .. .. . .. ':: ..... , 0.955 !acres :SlrlaalaCa � ... ... . _ •: '' : i - _..__-_........_.... ................ _ :.....__.... .... .... ..-- .. .._ ._.. ...... ..... .............. .... .s..: .. , „. { - ...I-, . .. .: ... ...:.." .:•. ,.._ >,,v' at. a OOD acres - ' - ..:� .��.. -.. .........'. .-.. .__ _.-i .. ... .. ... ....... _. .,.. ...... _ .._ lot - .. '. '. .. Detcnnloe t �. . .. . I ... ... .... T Efri - {s.t) ;Area s.t i) Ai .. .....I .. .. .. i . .. .... ; -k trMl{ve tx®-ar.•cbPmem Poa•tat bad �I}.). , .. 1 ! ' Ste•J BMP7: :'fgdi'a!tpen','7 ��"�65;`:: �•:''� *3:4226�1":+$t('it�&�' BMPA I ! I ..... _.. _ -.. .. ..... .. .., .... _ . ... .... _. .... .. _ Basedan Ex I 'om Caux _ I y. ..L.. _.........J_.._ 1 1 ! ...,.Js,n ,a LU.O,+( a19x lw t.x ...x z2a a _.i., , i I kn„ a A !B urtlonil6,i -- .dwfo. ,wit 4Wx: - ' 4r+::ia:.-, -••.v: t '.?fa.ES. _ .Nh. ... .sir, . -•: b a > LL w /:� 4 W Z '/� W J 1 9 Q655 'aL(es i .f. a 1 . .._. _ _..-'_.- _. _...-_...._.....: ._ � _-. _....._.._.-..._-.._.__�:._ _.... --. ___.._.. .. _..._._.. .:.. , _".. _._ , '...___ ._. ._._ _...._.... 1. ! I :3. l7eterrmne the I1tImtLL load cmterA the d s : ... _ „ .. .._.. ......., .. .. ... i . .. .1 .. .. ... _...-... _-....."_......."_.J>o _.._ ........?Ji..._....$e._(_).,- .. _ ...... ,- ..::.. i ..'(.. I[1,qu.F.il �,ulaiva btd lwd(pu,aad I eta• 3ltll► .:«+ ,•�{e^ .watt }i+r `tl;.. ��:;; J J O - drt x& Bwlk= � :. ..:...:.....:.: 1$�{`5?:i3 s.t or 0.429 nacres .. ............ - .. .. ..:. ... .. I , '� D.D00 wlxrc: lxa�rulopure ph,ephxow pars .t'm!) i .. _. .. _ .............. _ ...... .. !..... _ .. .. .. ..... .', .{... 11u :!Luf llsiun'Pc K•n'udwxbk nwhn,. e �,• I �1_.`._...., x a, �•# _ "Ol. aIt' Ja. '''t t ,:J 3.\ :jfi„7,); ~_.. it @ W _ L[.L i .. ': :.; '... �• :^: � .. .'.. 9.f. a I ,aere9 , I .... � - -' ... ..... .......... .... ..... ..... ......... _ ...1 .. ...:..... . , .! .... :-. ... ... ... .. .. .... _ _ ..-_...-_ ___ _ _.._ _ _ .._ .. _ _ ._..._......-__. .. .. ......... ..... .... _ _ ..-. _, ...... .. _... :L� - ((0.05+ 0.009 x Ipa11. J x tort x 2.2g tpution 5-23) .., ...... .... - ...} ..... ... ..... .A. -..... .... ._..._ _ .. .... _. ... __. ..... .. .. {_..... _. A = IVliwhle•m (aar¢a �- f..h,„ i;:�i r( .f5+ rYi 9.f. Q D.WO acres � . I ! ( IIIa ..4. .. � �.�•,..� "•�4•raaf.�,.N go09x r...096 A x ,....roue..: zz� ! - sed BMP i �4wr !relativeJwat-develn hoe (pouds�itl-.}+eaz)..-. (., ,ea �•. � 7i O E-..,-.. -. - -..:.. --`' .....__._... :where: tnetatotal .05+ .. ro,alaadrmtr;ri ,..proJm, _...-.. - --' . .,`?r): Total.. .. - . _ l_ _. 86i66.t1642e.F.a 2038 aetea .... ... .- .. _i ....... ... ...... .........._......._....._. .. ....... _.._-._ ".,...__..I."._..".._.-_..,_.-..._....__,...-. ..; - ! � ._ ._.., _ ...'... .-. _.._l.. ... ;.. _ t.ts veer I , I _ m]rgrvtouscovertoproposedBMP(peroattexprcasedinwholemnlren) 'fir-�... iauP._._ iP�t-devclopmcMptKcenc! - -- -A tY "!drmt urea la O sed T3MP IV) i i 0.75+(U.U09 x1„xnd,d)J-xAz2,:a ByuzlWnclO I - ....-. .. ... ..... ..,. r?�. -- .....- .. _ ... .. .... , .... ,.. 1.....----..... Lf ..--- --....,_..... _.... ,........i .._ _ .....i...__... ....:........ , , -lam )...._ � i ...1'.. . �' � ra.: aaa.. .1e, �x, •x .ql:- ' �. jr C'4 Q .�.,, Q� r� �i at =C0 �� UO .!le„1=(tom]post-de,•aloJmlefaih)tarviotncww+A)x1W=... j. I. }-.-.._.-_.;., i.. . 1 ... xxd .... ... .. i.. I ... ; . �.•. I i � 1r,axC �'laid I. ;t1[[u�� .wYs ,w� nut ',.._...._..:......................._.__..._.__._.i... _...._,-._.".-... _.. _.__. ._._. _.,-.-_..,-._-._:... _."_..._-__.1.._._... ...-__..._._.-:__.._.. ._.._.. ..:__.. ._.._.... ! I ! :ffie .Dtttvmitte Hee avezage land pY,u•rand[tioR(I,rnaaea)ar the ealathtg hapadl4••e eorOr(Ira.r.l�. - ...-. ,�' -p,atua�3.�IXtiOlVCP1,Yde4tl rcxa lady : � Lint= 0.05+ 0.004Y �' Z6% )1 X %.BB x2. I ' - )x.'' PerYe•7 I _. ....- ..... , ....... ...... ... ..... . _ 1_.... .. 8.... ... 2.._. ; ....... .. . ..... . ... -. ...... i,..n. a„a'..r.-ai:,,ax,rv„r..we.a-,:::.,Ibaux rl:.r+«s„nmea..rswwlw,'.+•w-•d:.•..i„x�„i .. .. M£ "r8[?�Ir�tiFTFM ION L$A."i1N � t7 ... i .. .! ... .. ! 5.06 _:po,olds .. 1M � , - i I A •lTlicehle erca� acrc.+�' i wll•N .Ave_rarN, land nv r itim fL._._.._l: � l � ..... ...._.. ,._.ei ...-_•-- s.._:....__.._._........__.._._...._.-...._...__._..,J..-..-__.-...._.-. _. _..: _.._. _...,..__.__.....y.. ,., ._. -._..{ .._ ' 1Fthelocalityhasdetenrrinedlandcovercorditiore.forird!vid!alwatersl�bwithinits.... ._ ... _(__..,__. ...... :. .. .. .. .... ... r.... ..f. - .1 ... r I ! '4. Calculate tie Illrart load remmrcd the osedB _ � 1 w'LU.05+(U.IxJOx +6% >] z 10.ffi ! zzYE 1 � M s: I i ta.U},.a ° - _.__._....._F_0111d..___..r-I?Y._.-YT°P,_,... L-'.(-i. .I..... ... ...... ..... ....... .. ..-. _.-.. - i ; I l5B . , I I ... .. . " .I .. �pouodaPuyear ,• : ( .'� Tim YI=R •n'vtr4,T�PWD' V k��" it � Q� f�LL JIa15d14"hOn, IJu: the watershed 3pCC18C Yalde fltdefmined by the locality 7i$ IWatl'd9hL•d. I I 0% ! i I ! :. h.suaad i. .. ... :. .. ....n.... .. .. .. .. ..! _ .. ... :. :... .. .. .. .. .... _ ... ' .. , ..... - .. -.. - i1,,m mI Efftur x LaNY (R tron i-ZI) _ i i ' ..._ - -_. stpn4 Demtmise the trl+tke post-dewlo�Npdhtao, l•a{t„,a ' f ...I .. ! _.._._.-.....h----------._:.._.__-__._-------- --"�R-_....'--�-----_ ...-_...._.. _._. .+..._-......._I. ..._.._ __...__... ....- _._ !.. ... __ ... .. .. ... .. .. .. ... ...... .... ... �!� .' «`IAi'• PRETREA MENT 4 PChIDM AREA) III fN o y �N . .OBierwise, use Itr_Cttesapeake ]lay defaulk value:... .... ! , { ... ... .. .1.. .... .. -, ... ..... ! �.. ' il•.Ixeea ltti°ra ! ... 1_..._._.._...:._.__..: _. :._._. ,.. .. _ -, i.. .... _ _.._ I ..-. _ .0 ..... t _ , y-(a.os-(R.!x19x 1,,.„) zAxi2s (Erlateus•zp,-. ...., 1-... .. �... ......_ ... .. jtvherca.®.„„- ' develo went total htw Ixmrr,s load rermvL•d by r BMP r lu .. P P P ollosed Lxnaldc ,1 1?s.. y4 __ _.._.._..-_.._._ ..., _ .._ __. -.... _... -. L' i (I ... .I _.. _ .. AS REQUIRED {( �,..{� M�7 > •.,..�( C� 1 � z,. al- ,_.-. ......__.._....... .--_...-..,..... __.._.. `` .•. .. .. ... .. -I' -,. ..... .. .:. .. i HtTjell, Ix}l 1 .hem: , ' rclaiw P'N!-,kvaluleoml bid load mispa av)��� � = hsam removal effic�ettry nfBMY(!>Rpresstd in form) . ;.. }•r.• l .. .. k1!!PT!'r7°P! .(P'.... X. ..... .. .. .. .. .. ... .. d � E 5.23 s - r) i aul wvcr slwl inMlolc taan6are load.->�:�SC oP.ncn?. nvl?v! '. '• _. p•� ";r "'^ •" W 'Lr rn I W -_.. ..._-.I-_......._....�_....---..._I-.._....'-"--'---..._.I+nrr.�_...-rCiativE _....- -� .....__ __ r past�cvdogmcM.ltttal pinspLorotn _a_=.._9��..._._(Pq!md kr.T..l...._..... ...-----+..... ..... _ .... .....; .b,y.,r .#Poe:?a. ,...... (Pceau�. .. ...) ; .... _...-..... ... f ' ( tt ;:.,.. A �. vy 2 ;._...._...-----.._.__...- ,.._..... ! I.............._ ....... ".............. ...... .- ..„ ..... ... .. ... ...... _ ......., i......._._-., i _. ._ . .............. ...•....... ... ....-- .... .. ... ...... ' }.. 1 _ ._.... ^ - =rpplLpaMexmgt?�l?a... -.. .:.i. .. - } ii 3.30 Pounds Yearremoved � I 3 ..... ...:. i. .��[ �. ... !..... .. ... { . ... :;.. ...... ..... 'Lrmm.amsa•, Pa _ - .. .._ ...-_. ..... ...... i ... ... _.. ........ ..... .. .. `Ll„-f0.o_5+U,009x ss96 ')1 x 7QBB �: p22e ] _. RAN N � W Ixtenree fire tA3<1 1 CfYIa,E COVQ at'dlt level merd atte it .BCrlt. .. ._. .. .. '. I .. !-.-.-._.._. �..... .. .... ..._.._ . ............ ,ng !?V ......... .., ..............-oP_._..........Pre__._..._. ....... .. ._ . .� ......t. .... ...... ... ..._...._... ...... _---..-.._._..........._..................._._._......._. .... { .f I � ! 'Pre•deveb im rvious cover. t ' ... l - fe rr ' - �::.: -..•'.. ar O.OW ac s '._.. .. _ _. 1 ..... _........ !....___ ....__._....._......__„._y_._..,___"__....._... ..__.-.. ..._........i.._ ......_-_.__I 12.4] ywatylvY.•-. ..�. . ! .-._.. _- - - - -- - ....._ n! - -_. ' - . ..... _..... .. _ _. ...-_ I _...._ S. Calculate rive total Itutant load removed the BM a : I i...... - _ _ f 1 I i - I- "9te•G,,,.DehminethenWktpolMaaolrem0a^dtegateueatlRR}. � I .... �. ..._. .. ......... ....._.1.....-._.............. ;........_.....J .._..-._,.. s.._........_......- ...._..._ ..-. ..... _.............: ... _---. .. i' t10tl { = izmov.raurt f.®,rartsaYr L.a,,,v:vta,ln ...(E4re iL - 0.9x [...-_�!n.Wv1t.-_..,...".-....-........ i..,.. AADLTK7GtlAL ADDITIONAL PS?MDIf� .DI. ... _ AREA AREA Z � CY CJ d strvctures .,:�.:.. ..... ._:......... ..............._. ........ ..._. ._ .. ...... kilof a ::. ,.. .::.: �:.. �.-..:..: e.f. a Q000 !acres � ... pa!'..._nS ._.__.__.-......._. �_...-_,...:...,.._.-_............�.....__....-.__......_._ ..__.,.>._...__.._. ..............,-:,._-._.... ;._.__... .. _ { .aeelmt .....?.... .. ....... .. .. ..i... .......... .. ...._ ....'!t•,-i... ..... _.._....._. .I..-.._......E ...._ ..ti-......... . _ - � ---''�-----._.._...__ _..._..__.-.1-..__..._a,_.._.-,_.........-._._i_.. __ .....- -'--.._.._ ......_._..._.._ ... , ..:....... .... i...,__......_ _ _ .._j... RM tt-40 'total CQ[N4F:Nl'fiA,1f,EO '$FAG :Atl r:d.fREfEFV(1[7N BED SY1 E AREA r wa = ::�.��:.:.:.:.:::.: :�'":•.:: ,. .: s.f. or ..:...0.000 _iacres... ... .... .. I .. )._-! _ i ...� IAimt.l0ad realoved by Jxvpoaed Bi[�s(pUl✓011a per I ._. .. _. .. ;... .....; .... ...._ .-. .,......... ......_ ..-. ..__... ....._.... .....-.... iwFsre: l.zmwxwald Yam' PRETREATMENT REVISIONS .other ....:..:..^:. ,.:. ';'.; :..: •: '- = s.f. or ... D;000..... !acres 1 • ...... ...... ..... ............. _.........:.-........;_ ....._ . -. `.:.... l ..i. ... ... �.. ..,. - :,. a.f. or ,- O.om ,rues....:.. I ! rtR _ I i 1 ... _._ _......._.- _..- _..... _ . - -...._ _ _ ......- _ . ,_.._. .... -. ..-,u. ..t,. ..� ._ . _Le: -�,._ f _I, ) R>t'=' Jzs - as i I i _.. -- Il�ans load removed'.._. Dead HMPIVo.I Equation 9.24 hYProF E4 �r tiACL[.C. {.A!`E37 TdPR INFLOW ,. ... ._. .. � I !. .!,.. .�.. .......::::�: �:.�..:.,:r,:•',.........-,.....-.0.000__...s�re�..,..'.........:..........._ _ ..._..r._._..... ._.._..._., P° _,. . .._.. ..,.�?!�•.._.... _._..__.._-... ....... i. ,... , t. R�....i`�...itwwJsperyeu[ __..i...-- I i.-._...._ ... ,...lh.aamloadramoved usedBMP1Yo.2,EQtetim5-24 - ----.._.__...-_... _ _ _.. _ _..._...._.. _.._ I ....I i r .._ f.._ ... l_..._ --I .. (SEE THE COUNTY COMMENTS ,.....-.-_-...._._.. ............ ....._.__.._. _..._._.._.-..._ __.._........._.-_....._......-____.._--._..I........__......_...._..-...___..._..-,_..-.._._..._,__..._-.-......_._..._., I _ .---- _ _ - .... ...... r _.. Oe..... ". �' _ I _.. _ ]]]floor lon,l removed used HMP Nlo. 3, tstim5-24 weiat= zee emervmn } ...i .. _ 4mo.aperfez Pf? b5'IxOP � . f .._ i . ..+.. DEATAILff>ROPTI SURFACE Feb 019 15, 2 Total 0 af. or 0.000 !acres ..:... - ---'-- ---.....: __...._ •!--'_' --I . _ �..-__.. _.. .... _-..__. .. ._..-_.'__.. ., _I_. t • .. _. .. .. _ - • 1 W = 0% I _' ..._ i L ; ! ; _._... . ............ _ __.. _, ..... 1.._-.. i.-__ _.-._. _A..... _-.. __..�._.__ _, __._, ._._ Lkdlry heat•rmt(rs�peactkeSBMP)irthe dt..` .- .... ... .._ ay.nuV 3-30 Total Polade per year removed i -. .-,._._ .... _ . . - .. � ...... .... ..- ._ _ ., -. .!..- _., .....- _� .. - l j @LEYATI.pla .___ C UNTY COMMENTS April 15, 20 1 total cm9ting rvrdR cover+A x _ ,-- . Ienstid0 -(. _ _ �-- - ._---_) _ .. .... _....�-; . . .. . ... !.. � 1. Ddc®nr dlafr�r�cd polldeotrcmmal �cOcy rotor - .. ! .. . I .. J I - 6- Verify compliance: lmnas6mwZ i ! ! (RI1,r a 100 r (EitamamS-22) I i 'Ti,�l,znun `"2 - F P +:'nM�31a}t�a,l,e_the 9�aas,red;nSTEP 1. ! i" ' t.. „ -. _ ...__ _. .-.. _ _-.l Ell = )R -- ----- - - -. _ -_,._ _ .- I.. I � +.nanvm I ... . 'bYl - dspery�rrem _ _ _, ...-_ .. l_ .... ._ ( .- - .., ..-_..__ .... ... 3.30 - I:�; "id May 2OR 20v9L -. .. . _ .. .._.. I Det•rttlhte the a deveb at situation. ' - ! ! _ _ _ . IR!.PP��- _ __. Pore .... _.. _ . _ . _ _. __ . .. _ . • _.._.. _.. _ ... ..._,.. _ .._... _.._.._ ..... _ .. s _ __ .. _ I ...: . _... f. fd Ranxealk" 1.fi0 Told Pounds per yeaf, t'«trai•e; ... .. i ..... Iuydcul �x,LLwant re•utal .,. _ . .... . _ . I.......... :O Removal forte F_xoeadetl� i i lei - Illml reanval re, rliremenl furls � cur): � i � •. t LEVEL 1 MIN. = �a'• LlF S •u II'I' +• d� . ... .. .! .. _.. .. .. .. __.--.. !. ... .. .....! _ _ ... ... ...__ .. r .. "I 1m,,: - rdalvs t>ns4.t�clo nlcnt mcil xwlinmuv k.Q equation 5-21 (Dmlldx llo'7aa) ,,. sr, Ts - i• I�'' .. - .. ..... -'Ihesite information dotcmdncrlmSTEP land STEP2proyidecnwlBtttrd'rnrmlionto,determine tlwaptQP??a�....._ .I... .. devClOpmen%S1aRt1011 ]alder WIIICh file CFlft'Ia W iB apQl�. Clatelr (,� tLle appre,X'i1iC dCVCI O�Frlefn 8iiUan011 a4 FOI104YB:�. _._.__.. .___. .. _.L.._.._.___--- YFF I -.- , - 7.a6 l 126] z 100• Both -, _ - pCPFOfTHrICe • ' _.. ...--...� ..._. _.,. l._ I -� - • Pb situation 111ti3nmststsofla�devtl wtercd}cads]tt>gpercertimpervutuvcoYer(I,;e1a,p)igltssllmwt �.- _.. 1..._-__. !. - .. ,."�--'-^T"" ,- ___.. )•__-. ... -_ :.__...--. .. 2. SuihctHMP(a)fnmTahle Slaani luwtc u•tLo al:z, �` 13 BIOFILTER 8t EXTENDED DETENTION FACILTY __-•_____ _-_ _ _-I _ _ _I o„I,�a •y,�rb,n _ _ _.- ;_ _ _ _.�...-. � - - -'' .. ,. (cgtnlmfltcaY,eraseland cover aadi4au(]:watprehedZemlilwproposad..mrgwao�enlannllcreete.s.totslpercent,';VADCRSWPP iom ewer st whichis less than or ttal to the land eotxhhm awatershed . _. _ r'Iv. _._.. __,_ (il?o-L__-. _ e9._.._ __ .. _ _. _ -------- _) ._- _... " Falseali _ t.. 26% $ 16% 1 _ .... ............ .. ._.....-_..__..... _...- ...__._... ._,.. .... _-.-.,_ : -. ..... lype I-• ri001MCY i Arm {ar.) .Pr®{sf)J7�i991L � ' I - a I '.t§�z"i. rzaepA... j. -- _.. __ . ..._ _ __.- . _ -_f --- - _ - _ I -._ . _._.. ... "Nip I: `elna rr, I _ - .-.... -..--• _ _..---._. _ ._ _�. .-.__ .__...-. - -- •: _ .. ._.. ... .. . _ } .- i Performance Based Water QuCalculation Procedure stsz. ''tedanaa ', a,s"g zBeseo aM1ra ti ; --... .� _ _ �.... _ .- ,.". .. . , - I aM1IP3� .. ' - ` aM1PC ' All t1NDEFIDAAAIS Tp BE STONE SUMP { l7AYL{GfiTET} UtaL�M1l'GiiADED) 1 . _ 1 C ONTOURS i .... ... Situation 2,TMs t:orslsN of land level n,e„ t where f1e crash, cent impervious cover a, 1s _ass thnn M eal� Yes of >8 [� � (4m x) ttatfietrverageltttdcut•I.,ofco litun(Iwatershed)aodthe.prupm_cdimproveme>tbwtlltaeeteatotal t2Lt._...... iP(O�dCt_.."•••.."3+.^L'iZY1�iQ08p't0. ,{t�R6•:hy�,� tlltt10�0(.'. ,!.oeanY.:'... .. ........Y'.Q:.:',,•,.:..�.:.�,. ... .:. - Albwlorl•- , , ' ....... .. .... �I _.. ... _ ... l' u�ss:�:ze' >:.:' :..: ...:... .. ... ,;. ... _ ��r ! t - .Attar E .. .... .. I ... 3. Dete�im,dwpog!rsm,lo.aewLrina!heque l>3 :<.R ...I i .. .. ... ... , QN VI- .-.� - :. ... .... ..._-;rmper,rrorscovor,(Ipast)wlechrs cahrdnnihclaralcover cordlnon(Ivrateralx .i _ , ._.. True i,,, o% sl�> 1 h•_.._-_ -- _ - - -. .. .-} .-... .. ... iO.( o .. .... ... .. a. I .. ... _ _. _. 4v. - (u-os+roan x [,•a•)J x, .„ m xlz.:)I {tsNr,a.aszs) � .. ° " eiL�e. - �d dtn• �•ia.:io •d�p.rYt�;a�eYer( ear• I I r ""° I ��... Figure 9.5. Typical Detail ofBioretention with Additional Surface Ponding 2 FOOT a..... _..._.._ _ ......._..:.._. ___... law'A . ...... ............ .................._!.___. _.-..-......_._....... ,..._...._- --..-_ __..._ ..:.__..... .... _. _.__-• .._._:....._ .._.. .._.,._......_..-... .. f-m 103(� �acrffi li le A ••- ..'... 452t82:$ a • - Bi>aP -.. �. .. I I. ._ , "4Y... �?_. arts (:. ).=. _.. ...... ...-.. _.._ ....1 .. .. .. .... .. iL:LL^r-'... ire ". .P°a.. .'cloPm'?r P.b9PP!•P�..- 0101"t°F.PraPoPP!t SR?masL�r.S?a): .. _... I-�• .. ! l,Ml'1pa�c�m,ed iu wMderambmsl 'P Trte ; t 26% >I,,,,yi0ea...__ t�0 i '.,.. .. .. ._'. .. .. 3. ...... .. .. .. .. .. ... .. ....,... . .. . . .. _ .. . .. .. __....-_...._..__-..._.._ :�'.7...J,%�?=`t`_'Mph°iPp:at.imperviuuswvertu-0m�oral i Post -development impervious cover. 7� i. ._i. ... .. .... . ... APylnl-ldrame(c arczmfroposcd BlrS (%ot!s) .... .. ! ! .. .., .., 1i TE n., I 1 i. aEa BOOB_ 'acros.. No 44natlon 3: This caaisla ofland daclapmn,t whew the e,dsht[g ptxcerdi ous cover C„• is .----....._....."...---..1.__._....._._,...._._..._.-.__.-.__..-....__..._... __._:____- . !"PaJI_.._-..___�_ma).___...__... .. 1 .the IIv lartd cover cmldtnnn Iwatersled _ .. ! .. - - i 6teisc ! o% >Lw,a.,a 16% � III'r' .. , .. .... .. strutsLaes - _- s .... ... .. _ __ t„v [aos.(o.caJx fox n ae .ze ; 7 , ....: `;-_... _ 1 .parlmgla[ _ ... -:'. "' aL or .. 5;500 iacfee . .. _ ... .. .... .. I ' ! ... _...,.. _ -_.- .. .. _ . _ .. ...'... - .. .I. . _ .. .... .... ... ._ .. .... .. .. ..... f _ p -; � =,;:r;' # i.. i ass hx...L.R, .m i { I. 'taadwa 4�.:,.,.,,,.�:;.,., - !; .i, af. a 0.000 . �� I .... ! .. �i { � 1 I 1. , .Y ..- __ ._ -. .'..:...:';.._:.::.::::,. I.. I ' .,.` 1 af. a O.D00 'acres ! I -` a05-(0.909 �_ et% :11 z an xz:e I t I (aH t I MEN I E HtfFitA1J1Y1tNl OctobeA22, 2018 : ... ------,.-..___..._...,I,,,,,.__,...-._.._.._._...-._----.:_..__._+._........_. __..__.... .. 4• 1 where exult cem impervious cover 1 - to sened an � Sktwtm T'Fnscorstslso anddeve .q$YeT ( 1rY ..:. a fl w the w.m �._ _- .L..._..,...__.._. ... . _ :rman _._._-._�...--------------__-----r-------� - - - - - ------ - - - •- - - - - I .. ...: h 1zo9- .year. { I I � � � � ' I. i i ----"._..-._-..----..._-.__-..__:._-.._..----_.._.._._.__�_..._.._..:..........._...._......._., i _ _ ,�'. a:'::•:>.a�c: • �: -:: r:,:.,. ,,.. � I ! .... .. _ __.-... ... .., .., .,, , .............._._._.._ ._. .. ...._ _ __�......- _-... ....:.... . , I - - ....�,._ � FILTER TFiI SC ALE Ictushngstarmwetgr!?iBMP(s)flatnddrepscswatertpaliy.___:... ___. I. ! �. i _. _... �Il, ,x O.W z2� . _ ... - ..... ....' .. .. , . : !,... ._... ...... - .... t j ........ t I e.00 'p0!mexp�rnv , I' I N/A � of-ar i 5.500 scree ...... - ... .. I ... .. .. .. .. .. I � ' .. . i - .. .l .... .. ..- � ... .. ,� ! ,iHEEI FLOW Ot€ . Proposed devet0 mxla The ClnetlB for devela 311tatron I ! '. ' _ :If PmrltP_�__.-_.._-._..�_.__.......__ . ___. ..,._kf°J1D.-._...._.._.__....-__. ...... _.....__-.__•'---.....�._..._.._.-1_--_-._.-__......_.- - con..... xi to l:e die BMP atd rto Ihiam removal is r 'red , ' than thelnademt level meetls_ . i ..ThecalcldanonJxocedttreforS>.Wabonlsltrpa,pore:VUe.JxoposeddeYelopnrerame,tlatheCrtlenarardoyalo-Qlnenl.__.....-.. .__.. { ..,. , � �. - 0% r a.00 x 229 1 1 Iu.Us ! I?w»..._......Sa_'�.�_.i....-..-_._...:p .._......_-. .._. .......-._...._.. ._.-.. :.' -.' i ! ..... ...! .. ' _ ... _. ...... ' 1' ..: .: ... .... ... .. . ; .. ', i ... .. ,L. _ tLm )xlldz Iw'ywi U „ (total t-�eveloptrcrLttn>pei[vtou4covcr+A)xIW= 63% , , ! !.----..._. i I -' 1...-.._._.--'_'_- .__.___..:..C.---'--._.�___......,,,.__.._...,-._._._._.-_'_. .-,.-__.....-.-.-_ F._._._.._.•_,"_-_..,................ y ' I ' i ! - FILTRATION !:� tJC 1 i=NEION 'r.- DETENTION �., � •t:.•�.` :r `•'( �r C.ti-. - ti'i. 'i. �:. �•. STORAGE TA 0 Ui'L F ,. ....-- ........... .. : _ TPP 4on lire �&•wvrkzhcet 1 � ' :311uah,ols 3 or 1}len to 3_ _�!.-_..-....-...___..... ... ........... .. ..........._....... _ .. _..._.. .-.... ...- , .... __.."..-_..._,.?i .,.-..:_-._..)??��-._.... ...-. ..-.-°Per.. .... _. _. _. . } - 1 .._..:._ _...;.........I ...... .... _ I - m r......... :.. .....: ...-_-.-... .. ..-. .... _... ... ....: ..... �-.. .....-.... -�.... jfrtn I[.as (U.W9x I o% U] x � 0.W !x2 , I � � { _I I :>� ;Detee�eu the avewge lard cover tonddatn(I,,,N„t.,J 4i the eYrattog inlettvfttua L.uver (7.,1a.. •b .. .. - ono !pandap¢v,.rer I ! r ... . . ..... ....... _ . .. .. ..... _ , I 11 ..;... If, .. ..._ . ,..... __-.......-_ .._......•,...._... _......_.......,_.__.._, ._.... ..,....a... .. .. 4 .n. _ + , F .:::.:::•.� ::-.. Ii101•it ktN01UN CI=LL ,�r'.l• I I i YA DCR SWPP , ! , 1AxMile Performance Based Water Daal CelculantRt Procedure srrcxnonz...,....... ;. i. CRladaN: au dluhd Iwd [czu��xlbv LLz: z land coveir condition , : � � .. ... .. .......: . . P-'... .., ........... .. ,- HA•rO, ... .. ..... .. - .. 1 ._.._........ .... ...... ...... :. .. .... , ..........: .. _ ... ....( .. ,. .... ... .. I ..'.... ...; . ... -.. ...... .: III p ,-, '- - ............ ............_. .. 0% S 10% i ... __..... _ Ifthe lOGtllty has leis]-mllCdlaOd eDYtr CO7ldthOrE for mdlYld4lat W9DOISLDds WIpM iffi 1 L.a..a �. CHs[:._ Lux'... ......... �!W.M® _. ) ... :.... ._. . ,... i ......._.. . J'Ixisdicti I � i - 7 f.... PrpJ3ct _. aN-Bbca 7iYYP.Q�OLaal)0101nF�.ra ElOPia.a aMMap1) ' :' -_.-. _ -_- .. _ ___•__ _ ... __ _ tacaar Nii4nwtedp � :.- :.; .; ., •, f,..: 15% ' tso tlx watershed sptciSc value ilotaanzled_ by tEle locxday as Iwalorslnd: , i .. .. ..- . _ . .. ' .l l , .i:. I .. .. ,_ --.. ,v(. _-..�..... ...„_ .n..... _ _ _. ., _.. _ ... .. .. . ... .. .. .. .,. •, cEofa t..l...e.puyl•:bealejrntml0adphusf,karlw lunlrcmwedhY R r�re•'), i .. ` I I � � : Ixirmie.l : � i Jim . C]OrC , ,.-, . : . -•., r i - ...0°h ... .... ... j. rodaiaml I cBiaomy ofHA�,(mad2 4 iC. No. .. �iR-Fe1~!t :': ::. .. .,. i ..__. ..... ..... ' , t .-... .._.?ap PullWnot�minvil .... _ .. lt4e the Che eels default valrra. Olklxwi xS.... • see.- .. .r - .. foul Rt.�r,F-4udon5-z3 "LIfi11•- 'mlative A R' 22841 �v zrruvwza a7EP l Wadden l: ia, tBi >),.,,.w ....;. .. , - . .I'._... .. - •. r P�-dr ..°PO1Ca.,..4h091'sRr W?4e•'? (pwmde }xryi: ) i , cel oral Dui rnxriep Iw,Im!,ed-!I63'a ..__.i. .__ _ ( i ?�.. ... r;._._-..-"_ .._...... _._-... _. ..,,.-_'.._.. .. ...-._.... _-_.......... ....". .._ ...... .1. ....._ C`(Jl11CFNTfiATFD OrJ-21-19 W �I?aIONAL a„mztnr; oNiestion 2urimrix frumw!cda4m ptowduo lkufl�, Fxhe I ts% ! %,..�.aw, aoz Peunde Oar YOu rena,0a j ' FLOW WITII FOFiL3AY ECG -....---� 'i`_ .._.-_..; 1_.___.. .. _ ._ ,...-... _.. _. .. __'- _ _..---. _.._ ` �a ..-: � ... __..._ ....._. ..'_.. .... - _ .., ._i- _ ., ._..- - -i. __. ._.. ... i6S5 _ .. .. i� s I � ... � ann par eu renvsa - �.. ;. ^ . ..........:.. �,.... eve ...... ... ..... ........ ... ...... .. .. .. .......... L ...- ... j.. ...�i .. ....1... - .. .... I .. .. .... ... .. � � � I WRRENILYIN 1 � m... +_wrrmr rentr•tl l I ; ....;..- PLAN VI'W .. _ ... ..._: _. ... ...... .__.- ... .."_I .--... ._!. _ -- _ _ --. .-._...... ....... Dei@I'lt't11e the _ .' , Nl Wn COVE Df sert. _ ... ettstrflgtrope ..Au _ _ year ! f ' ; 7 ikter•ineaemhltve .in m heraema[ , llts@•f ... .. . .. ...I"P._...rbP"E.. r!, ....-.:k»!•........ . ...._. .. ..; ..._ 1 ......-. .... , .., [amen )r,�xoua Celt". .... .. ! t:... ...,__.. ....'...-_-....... -.., ._.... - .. -...,. _... .,- ... _. .. I ..... _ ... .. ...... __ ................ .... ..."-.. _. . _.._.. _.. - -- .• __ . .......i. _ ...- ., .. -�PlMllda ! ! I � I' i .. .,.... ... .. .. � ...- ... _;..... . ... .. .. .. .Pre dtYelnRlnCOt LreJ1lNi0a8 coven t . i _.".... ., .. i. ". _ ... , ..-.. ...J.. .. _ .. ..I" �i�, � J�. n .. ... .t... ..... ..... .. ..... .....-. ,=10.05+i0.009'z ,,.:,�) xAx2S8 (Rgaa.•anb16) -. .. ...[.. , i I I }y.!++,•r. .... ...-...mx.L .... ... ..... ......... _.... .-..... .. '. ...... a.. ..... .. _ ... ..... ..,... 1. wlma: l.p,.pl9-rdatire Po-davdarweratatll Jan9,tmnna load (pmah PP.!.)'�'!i .. ,!. ..._ .. .. i ..... .. 1 ( .1 .. ..1 .. .. ...lea .. _ .... irucwres m .... .. , ... ..... ... � I .. ..,.. i... .. ' ..D� �... �.-._ .--. -. i. caleoterc,Ac oral pollload rcam}d bk Qp BMI'ia); � .... 4 � .. .. . 1, i' - -afar i. ..06= aerea ! .. .. -. .. ,.. ... .. .... ... ._. .._. ._. ,...i ... .. ._ , .. .. .. - i � ST F'E F'RO OR EQUAL OPyE 6L0 7ECTLQfV EQ A O V rai,M•eNRrxim a:,nfpvx•. ¢4,eadi:wW aaend: , r 1.meewLffl !true+N,]I lr�ndy,yl [HGait1a115-$�J � 1 , _ Y � i ,a,6..'e..r.�du ., f i l I_ T _ .. _.. _I _ ... .. -.. .. ._ .. � .. allele: J f......a'to4lppttmant_loedrtamed bj'lxaP,HMI'1 ' °i iearss �.� I Z A !N //, x p$+ UfYJx -__' a% � )I z T.ea z219 I I � I 4w !n L,.' S"'___ I � i . i I ! t3J 'ae I>Qye!9:. ,.. .. ... t>W '; • r .. � . - ._._ I ... ... . 1. n._ . _.... _..._.. _:•-� __ __ _ +.. af. a O.ODD t _ � _ _ _ 1 • _ -. . y.... _,.- . _ ... ..� .-. ... . _ .... 4. L - ..I .... ._..... L........-.. .. ._. - I. . .... _ 'loon. by,W owd 9!'� i. • I. i... �-'-.N.w,- 0ax1oedlmtovM R2v]PNa LE ona21 tO!t: 1'?. ° MAX C? W N _...... ... .. .. r . ...: ... .. .... ..._.-. ...-._-. ... ... .._ .._ .. .i ..'__. ., ,__... t ..... .... .. ..'_. __ __... !.•.-_--i_,...-__l-_- _..•i ..__...-• _..._..._..: . , _ _ ...... _ .._ .. .,._.. ..... _.L _._ .. ... .__., .._ . ._ ... _ .. -". .... - . _ .. _ . _ _ ..iTotal .. a_ �I"--- js.f. O.pOD. �...Jefxee ._! _ ! ( 1,„n...i.:- Pulhdetaluetr.ra,velln PRN"ead RMl'No 2.F lwtir,n S21 .„ _ e W � � I} '• ,.N. __, .a .. .. .... -..._ _ ". _ _ .. _ _ .. _ .,,.. ...-- .. ,_ _ .. „. ..-. drrnmetd by }xopoad BTdP 1W. 3,E j L.�,xa.aa '. .. .. _ IoOc!ara,oal I. ..,.. � � FULL EXTENDF� Z W � - . ... wl,vc: +.xU.,,.,.l, i,a"ire Fl,>!tevd lro4 ek,zta.a !m!f in,�r.,�>eT•�r),I .... .. .. ... i Imo-+,mwmduacemBfimMsp,eYiwwwtlNzbean:�mctTsa•wle D.rv,N.L wtna'IGM nmmlamsnt:xmk,mml ! ;' _. .. : �.. �Im.,.p. (total exiabgg imparviola cover+A)x 100=D'. .. .... .i ... .... ... ... .. .6 ij, a" rm!Pwml�r�l.rta,�.a 1 I ..�.. .. .. _.... .. .. t l...-. - DLTENTION STORAGL .i [L - `y z Zi Z Q _.... . Per._......_...( ; . .... , 1 ,_. ... _. ! � _ 1 1 .. *: _ ... 1• ' .., I ,,_ - .... --5- -,r;.. >As. The area should the sewn as used _.- .. _..... � .. - ...i I i ' ' OR z J _ % -a.bs+o.[avJz l ,eve ' n x. ]aa zza0 "....._..._..._.........". .Tk"_N"'-•.`0-l__._.1_..______.,.__._._,..__..__.__._-___-.._.,..__."_{_.._. _.._._..�____,�._-r___-_-_ J -, __.. i-.._._- . __.__L._.._-_�_-_..._-,...,.._.......-_._-`__.-...-.-.. _._....-___. . .....................-_...... _........ ..-_t..-................_.._._.....-._........_. .. -. _.,_......-: .. ....,_:.. _-.-...._ _...... )....-.. ..... _. .. I ir,�z.n!aa- eau rod Paam,p.ryaermlo.a ;.._ ,-- .... I l•. I•- ....}.-.___._..._.__..-_._.__.' _.._. ..._�-�dikrmrF 7.ffi ToYl Paadaprymr,envedl. .._ IDe devebpment akuatiaa ' etmme rie a - - ...;_,.�_._ .._ _.PPYP!!"� ._ _ ,__ ._...I _. I- ... ., .. .I. ... mKagmvliai.E. CONTROLLED L6YtL ;r - OVERFLOW - t - .,. -.. _. _ _ ._I , ._,_._._ _._, ,.. .__ . ._.. .. - ... - - .. .... 'it£ortnad /•t r � &e• s ltetrn woe re mra a port-ac.r:te►awrt putw.m b.a ay,a :. ... ' _ ..."� !.. f .. .. 71ie- site m determined in STEP 1 etd STEP 2,proyirle emtt_ilmroatian to datanR Ile t11q.aPl?tMY?.......... _ _:- --.. _ ...... : ......... ....I .. - J -� ` � _..........j��OYt17eftstuationulflat_wtnchtlleperfamencecnte_rtawtll 1.Check(�iheepL�Pnatedevelo7waett[sttvtdionasfollows:t ._.,aDpY .._ _ -._ _ __ _ _ ..... ...... EXTENDED DETENTION O -..-t*„,=lout+{sitarsxl�,);xnxz?Jt.�Cgstl..s-21J ............:.....-:.... ..I.-.....-.._...{... __! ' __t_.._,...... i SECT:9N YIGW' �' J 4.r - Inwtaora[aP� !•+ �„�[t%e� '°am•'ho1e�4Y) I i No !:Sizrtion 1: !Tina consists Of lard det••elopm[a[ v+huc the C?rt5h�,. perc�t vnpereltnn COVa S1aix4n,E� i9 less than M ) ........_.. . _ ... _ . _ • MEASURE SEDIMENT ACCUMULATION LEVELS IN FOREBAY ;- -,"� egtmlrath�ave lanicovercondition'twtrcerste sod] rcYerr}emswdlcrtareaooml rn mP RETENTI.ON IN SHELF OF EXTENDED DETENTION POND Q q Z p i-+ i andihe proposed - F?� - - MONITOR THE GROWTH OF WETLANDS TREES AND SHRUBS PLANTED. rye _. , � P..Pn . ^ Iw ❑ - - r.ffi x2.ze I •--_.,. __ _ _- _ y...,. _._ . ! less lard cover hm COVP-r re [rns wfuchra� a Nd�' '�v �(-� Jlpost Si% 51e,,,�}� � 16% I (.-- _-,-_ - L RECORD THE SPECIES AND THEIR APPROXIMATE COVERAGE, AND NOTE THE PRESENCE OF ANY INVASIVE PLANT SPECIES � C� m 0.' ! i� .i ' .i .. 1 T i OF STORMWATER INLETS OTHEPONDFOR Q .:... ...... .. .._I . ..... ! __._ • SPECT THE CONDITION ' Z ... _ ...I......._..,.. sr• a trhraaK a: reiatra tool w,medm raver : . __..._._.___..:.,___.'._..__.._._.:_..__.__....___.._-...___;_.._........_' " ' "' •' ` sec an M equal vs ;�twtion 2: Ilus coreials of land level rant whore the exlstiog.percera„irnQer�ious cover..�l,a,�.}s 1-;,,,,�-...^_� �,. .__. MATERIAL DAMAGE, OR UNDERCUTTING. -_. ..__- - •-• --..^_ _ _.. -.G... _.. . _ _ - n1l?'........ _ _ _ . Detail o a ► re en ►o Basin ►n e r e o an on Figure 9. �, Typical D t •J f BOO. .t t' n t3a with' the Upper Shelf f EG1 Pond Fig yP PP � � I RR= i i ! + ! .ro tic eYtratic land cover condition (IYY81A2811t1) and tic _- sed imptovPmoas will creams tthat,ptaemc . INSPECT THE BANKS OF UPSTREAM AND DOWNSTREAM CHANNELS FOR 4--(o.9xt.Pm„h„O + ........ nx = _ 5.1 1, ... .... ... ........... ..._.._--_ _. a--... ._ f _........- �..._..... -.-.-. r..........._t_.-....... -.: iwtl toyer (ipost)whichis efdan 0c ay« lad cavcrcadibgn.(twatashed _. I EVIDENCE OF SLOUGHING ANIMAL BURROWS BOGGY AREAS WOODY ..._...-.. I I .. " "(-.. .. _ ..,� { ! ' to � i-'1•, itvlx veer I JfiF, 4.27 1•_. _P?!, _.- .. .. _ _.-.. .... ...... ... ...I - -.... _.. ,... __.. _I _.__ '....I T<ar 0% ?1•Nanrna -_., 16% -.._ ._ .._....._.._....----. .. __..... GROWTH, OR GULLY EROSION THAT MAY UNDERMINE EMBANKMENT _ ... _ _.. ..__ ....__ -_ .. - --. _, -!•!R - ....._ '"-+-' -'!-- . ANNUAL BMP MAINTENANCE REQUIREMENTS Ga ; ;ate ,....._ ? I_ INTEGRITY. RR - r,,, - I"y.``") ! -. _ ....- ._ _............. . ..-... ! ! Tore I 53% > Lma.at.a 16% ! • INSPECT POND OUTFALL CHANNEL FOR EROSION, UNDERCUTTING, W aR•;__J-� w!�!Per3� t I I -.......______-...--_.._..._. _..... ' .. ..... . ........_.....L._ _.._.............._-...1..... _.._..,-._. _..,... _....._...._ RIP -RAP DISPLACEMENT, WOODY GROWTH ETC. BIORE od ! i...". ... .L.... ..:..:. ..., ....:. ... ... .. ..{.._... ... i ...-. --- _-- ....._ .-._..J___ w ;Sknetlon3: (This consists oflarzi dtvelopmera wtv" the existing percent imiturviews covert is gtalcrt INSPECT INSPECT CONDITION OF PRINCIPAL SPILLWAY AND RISER FOR _. &eo7 "tu�mtp 5erimaoagemeatpnik• (B� T•rthe ulte. ! ; i ! � E the avcrac land cover condition ��Iwatcrslx d). _ ; _ EVIDENCE OF SPALLING, JOINT FAILURE, LEAKAGE, CORROSION, ETC. False Im,nylb >I�� 16% ' ! j • INSPECT CONDITION OF ALL TRASH RACKS, REVERSE SLOPED PIPES OR • MOWING OF GRASS FILTER STRIPS AND BIORETENTION TURF COVER AT LEAST 4 TIMES A YEAR SPOT WEEDING, EROSION REPAIR, TRASH REMOVAL, AND MULCH RAKING TWICE DURING GROWING SEASON ' • - ? I , ...-... _. _....,; lkleru:ve{�regered poummamol=l etlieimey, �xrlg,ak:-._ _..- ... . __. _.. _.. _.:. ___..A.....----L..__..._ _.....` _ _ _ _ _ ' i . - . ... _ _ ..... .. .... ...... •... .... . _ .._ ... FLASHBOARD RISERS FOR EVIDENCE OF CLOGGING, LEAKAGE, DEBRIS ACCUMULATION, ETC. _ • NEEDED S INVASIVE PLANTS USINGRECOINMMENDED ONTROLMETHODSASNEE ED A ...........:........_J..-...,....... ..- ._._. ...._ ,.1 ... ......._.J ... _. _ !_ . -. _.._. ...-...... r...... Nrs ,_tr-•) x !ao rsa�!I®s•m . - I �;;: Situation :Thiscorsistsoflanddevelopmentwhorethewstingpercetaimpc+vimscovcr(I„„, )isservcdltyan a.... stoimwater..- s thataddressesvia[rz l ' INSPECT MAINTENANCE ACCESS TO ENSURE IT IS FREE OF WOODY ?. • REMO • STABILIZE FILE NUMBER - _ , ,,,-,„_I ...__ _... _...._t-.__....... l ( VEGETATION, AND CHECK TO SEE WHETHER VALVES, MANHOLES AND _. _,_!:.__ .._---..1 .._ _..._ _s..... --.... -.. _._...--. i _._.•---;-...__-.."._i---...---....___......_!...._ ...... i • SPRING INSPECTION AND CLEANUP 8053 tom: tar.'...t{t4aPrPPn m!pmyPTameynoy' RR ttmll,.oiercmvdr«ptim�m(Iemt,prrrtarJ I ! ! --t ... --.............__,_.._.__._ ._... .._...._-i........... .... r_......_......,,......_.j.. ,--.�_.__.-..._ Iflhepro posecdeveloptlertmoetsthecriteriafoc,devel _}a'u.Situau l,...,_'; ... , ,,. ,,. ----- ' r � LOCKS CAN BE OPENED AND OPERATED. ifththelow • CHTOMAINTAINA3BVCHLAYER _. .'_la!ird P"�t.]ere!ny:,rnxw,r440"adan,rr, tam], h:wur rrs-n ux,.dxP?r`"'r2.... .i..-. .. ;. .. .i... ._. _ ;at tlersit dove] ts, coreideredto be,Ow SAP and Pop .. �, • INSPECT INTERNAL AND EXTERNAL SIDE SLOPES OF THE POND FOR • PRUNE TREES AND SHRUBS PRUNEMEESAN SHEET ' The calcldxhmpnx q ltae_f,u $ituatianl% stops hsn,.,Iftlre proposed levelopmc meet%tt criteria f� develerpmtart. EVIDENCE OF SPARSE VEGETATIVE COVER, EROSION, OR SLUMPING, • REMOVE SEDIMENT IN PRE-TREATMENT CELLS AND INFLOW POINTSONCE EVERY 2 TO 3 YEARS SihffiiLro 2, 3, or 4, tLmproctrd to STEP 4 mthc appIropriate workslXx t. AND MAKE NEEDED REPAIRS IMMEDIATELY. I • REPLACE THE MULCH LAYER EVERY 3 YEARS i � C1.1 L // POST BMP CONVERSION STAGE -STORAGE Elev(Ft) Storage(CF) Storage(CY) Storage(Acre-Ft) Area(SF) Area(Acre) 642.000 0.000 0.000 0.000 195.840 0.004 644 000 831.004 30.778 0.019 661.054 0.015 646.000 2823.802 104.585 0.065 1361.270 0.031 648.000 6453.083 239.003 0.148 2296.149 0.053 650.000 12157.308 450.271 0.279 3438-624 0-D79670 652.000 20376.829 754.697 0.468 4818.813 0.111 654.000 31584.229 1169.786 0.725 6426.504 0.148 656.000 46234.511 1712.389 1.061 8261.595 0.190 BASIN STORAGE PROVIDED = 1441 CY 0 655.00 (TOP OF DAM) 665 STORM EVENTS FOR BIORETENTION FACILTY EVENT INFLOW (CFS) ROUTED (CFS) 2-YR 10.95 6.60 10-YR 20.62 8.87 660 100-YR 39.86 40.63 STORM EVENTS FOR EXTENDED DETENTION FACILITY EVENT INFLOW (CFS) ROUTED(CFS) ELEVATION (ET) STORAGE (CF) 2-YR 14.02 8.83 650.25 13,172 655 10-YR 26.08 19.49 651.27 17,380 100-YR 89.43 90.60 652.32 22,180 DAM CONSTRUCTION NOTES: 1. GEOTECHNICAL CONSULTANT TO SPECIFY DAM EMBANKMENT MATERIAL, SEEPAGE CONTROL DEVICES, CUT-OFF TRENCH DESIGN, CULVERT BEDDING REQUIREMENTS, AND OTHER APPROPRIATE GEOTECHNICAL 650 DESIGN REQUIREMENTS. EMENTS. 2. IMPERVIOUS CORE SHALL EXTEND TO THE 10-YR WATER SURFACE ELEVATION UNLESS OTHERWISE NOTED. 3• FOUNDATION AND ABUTMENT AREA EXTENDING 10' BEYOND DAM FOOTPRINT SHALL BE CLEARED, GRUBBED AND STRIPPED OF ALL VEGETATION TOPSOIL AND/OR ORGANIC SOIL AND OTHER UNSUITABLE MATERIALS. 4. AFTER CLEARING, GRUBBING, STRIPPING, AND REMOVING ANY OTHER UNSUITABLE MATERIALS, THE SUBGRADE SHALL BE PROOF -ROLLED WITH COMPACTION EQUIPMENT UNDER THE OBSERVATION OF A 645 QUALIFIED ENGINEER. THE COMPACTION EQUIPMENT SHALL CONSIST OF THE HEAVIEST POSSIBLE EQUIPMENT THAT WILL NOT CAUSE DISTURBANCE OF SUITABLE SUBGRADE SOILS. EXCESSIVELY SOFT OR UNSUITABLE MATERIALS SHALL BE REMOVED AND REPLACED WITH COMPACTED FILL. WHERE ROCK IS EXPOSED AFTER STRIPPING OR UNDERCUTTING, ALL LOOSE ROCK MATERIAL SHALL BE REMOVED PRIOR TO PLACING COMPACTED FILL. ROCK SUBGRADES SHALL BE INSPECTED AND APPROVED BY INSPECTOR OR ENGINEER PRIOR TO PLACEMENT OF FILL. 5. COMPACTED FILL SHALL NOT BE PLACED PRIOR TO PERFORMING THE REQUIRED FOUNDATION AND 640 ABUTMENT PREPARATION, OR ON ANY FROZEN SURFACE. COMPACTED FILL SHALL EXTEND TO THE FILL LIMIT LINES AND GRADES INDICATED ON THE APPROVED CONSTRUCTION PLAN. COMPACTED FILL MATERIAL SHALL BE OF THE TYPE CLASSIFICATION SYMBOL SPECIFIED BY THE GEOTECHNICAL CONSULTANT, OR OF A BETTER QUALITY MATERIAL AS DEFINED BY THE UNIFIED SOIL CLASSIFICATION SYSTEM (USCS). RESTRICTIONS ON LIQUID LIMIT AND PLASTICITY INDEX OF MATERIAL MAY BE INCLUDED WHERE APPLICABLE. COMPACTED FILL SHALL CONSIST OF MATERIAL FREE OF ORGANIC MATTER, RUBBISH, FROZEN SOIL, SNOW, ICE, AND PARTICLES WITH SIZES LARGER THAN 3" OR ANY OTHER DELETERIOUS MATERIAL. 635 6. COMPACTED FILL SHALL BE PLACED IN HORIZONTAL LAYER of 10"-12" IN LOOSE THICKNESS. ACTUAL LIFT THICKNESS SHALL BE SPECIFIED BY THE GEOTECHNICAL CONSULTANT. THE MOISTURE CONTENT SHALL BE CONTROLLED SUCH THAT COMPACTION IS ACHIEVED WITHOUT YEILDING OF THE SURFACE. EACH LAYER SHALL BE UNIFORMLY COMPACTED WITH SUITABLE COMPACTION EQUIPMENT TO AT LEAST 95% OF STANDARD PROCTOR MAXIMUM DENSITY IN ACCORDANCE WITH ASTM D-698, AASHTO T-99, OR VDOT SPECIFICATIONS. ANY LAYER OF FINE GRAINED FILL WHICH BECOMES SMOOTH SHALL BE SACRIFICED TO A DEPTH OF 2" TO ALLOW ADEQUATE BONDING BETWEEN LAYERS. 7. COMPACTED FILL WITH A MOISTURE CONTENT WHICH WILL NOT PERMIT COMPACTION TO THE SPECIFIES 630 DENSITY STANDARD SHALL BE SACRIFICED, DRIED, OR WETTED AS NECESSARY TO PERMIT PROPER COMPACTION. to GENERAL BIORETENTION NOTES: m ca 1. ALL DRAINAGE AREAS TO A BIORETENTION FACILITY ARE TO BE STABILIZED PRIOR TO INSTALLATION OF AMENDED SOILS, MULCH OR PLANTINGS, 10 2. AMENDED SOIL WILL ONLY BE PERMITTED WITH A VALID SOIL ANALYSIS REPORT. NO AMENDED SOIL SHALL BE ALLOWED ON THE SIDE SLOPES. 3. UNDERDRAIN PIPE SHOULD BE MIN. 6" PERFORATED SCHEDULE 40 PVC (PER AASHTO M278) OR DOUBLE WALL HOPE (PER AASHTO M252). PERFORATIONS SHOULD BE 3/8" SPACED 6" ON CENTER ALONG 4 LONGITUDINAL ROWS SPACED 90' APART. 4. UNDERDRAIN CLEANOUTS SHOULD EXTEND A MIN. OF 6" ABOVE MAXIMUM PONDING ELEVATION. ONE CLEANOUT MAY BE FLUSH WITH TOP OF SURFACE TO ALLOW DRAWDOWN. 5. ONLY SMALL MATURING TREES ARE ALLOWED TO BE PLANTED IN THE AMENDED SOILS. 6. A PERMANENT MAINTENANCE ACCESS EASEMENT MUST BE PROVIDED AROUND THE PERIMETER OF ALL BMPS TO ALLOW FOR ADEQUATE MAINTENANCE AND REPAIR. 7_ AMENDED SOIL WILL ONLY BE PERMITTED WITH A VALID SOIL ANALYSIS REPORT. B. INSTALL WIRE SCREENING AS NECESSARY AROUND ALL OUTLET OPENINGS TO PREVENT LOSS OF MULCH. BIORETENTION WITH EXTENDED DETENTION11 NOTE: THIS SHEET IS FOR INFORMATIONAL PURPOSES FROM APPROVED PLAN DATED 5-21-2019 ------- -- -- ------ -- ----- _- ---- - -- - ---_._...___- _ _- - _-----------.... ---------_ ___ - --- - _-- -- ---- ------ ------------ BY ROUDABUSH GALE & ASSOC. INC. PROPOSE I GRADE EX GRADE I OUTLET F ROTECTI -. ---------------- -_---- ----- ---- -- -- -_ TOP OF BIOFILTER MEDIA EL: 655. 3" SHREDDED HARDWOOD MULCH LA R .---- ---- --.__ _ -_-_ i _ - ------ ,.. PRETREATMENT CELL CLASS W1124 S RIPRAP 1-_- -. EX TOP OF DAM 655.00 _ _. STONE VIER & SLOPE PROTECTION__ EL: 656 _-_-- ?4fl -------- . ...... __._.--._...--------_.__._...-------L---.-------- E)L 25' EMERGENCY EXISTING __-.. _ 6" MAX PONDING _ --------_..-- --------- ----- SPILLWAY'-653.00 60" RCP RISER - - . EXISTING ' y x �• - - - y. Y1� ,• - - - C V •;x, { nus ` " 1 T h ti tr __'---------------___.-___.._.____ _...-__-.__._..------------- ----------.___ __�..._ - ----•-_-_ --------- -- - . " nk 'r kr � ..+ :# --_- ___ -DEWATI=-RING A.'�`i l-V ORIFICE 649 50 N^k L. K < � .� �`„ '.�� x"k"�`.;Ak .>y �� �.A r,�v. •,C•. y t",Y . :: x >. � }� t•t � ^r,� - NIX y..f Y�, JitT{�. f'1.,pxX yt f X R , C F , / f• r ,,. /y. , r 7v ,� ' -' . - ---------------------- r -_-.__-- STONE DIAPHRAGMS w 48" OF CLEAN WASHED _....__._ __,._----•-_-------- ..... .__. _-.___ ------._..---.--_ .-_-_ -_.-_.-_.__..____-- _____-------.-___.__---.•-------1.._._-- - ____ _ ._..------------- --...----_----.----__--.-- ----_.--_____----- �57 GRAVEL TO INCLUDE UNDERLYING FILTER FABRIC. - BOTTOM EL: 653 -----'__-.-- -__ - -___-.--_ 36" BIORETENTION SOIL MEDIA__._ ___._. - -- - ---•__. - --------_--------____---..._-.._._.__.._..----------------..-..._--_ _ 3:1 3:1..__-_ f BOTTOM EL: 652.5 -- , 3 MIN PEA GRAVEL LAYER- f TOP EL: 656 --- -------------- ---_...___.___ _.-..-- -...------------___ .----- ---------------- _--- -_- ' - EL: 652.25 VRIGGID SCH 40 PVC UNDERDRAIN OR------ ........ -..... - 12' MIN 7 GRAVEL SUMP LAYER EQUIVALENT CORRUGATED HOPE 01.0% SLOPE TO INCLUDE UNDERLYING FILTER I - • r'N _ � *5 .5 _ .._ CHOKER STONE FABRIC BETWEEN PVC AND " • :,. <.. ', , , • r' r. - EX BOTTOM OF EXTENDED DETENTION FACILITY = 642.00 A (2) NEW 8 ORIFI=642.25 REFER TO SHEETS C2.0 & C2.1 FOR -----•--.-.------_------ ---.__ -____-__-------------__.___._.- ----__--------_--__-� -_.._-_ __-'-----------..---- EXISTING EXTENDED DETENTION - --- -- -'-- -- - ! AMENDED CHANNEL AND BIOFILTER - ------- ___.._.__..-__'-----_--------__--- FACILITY AND OUTFACE TO REMAIN. --- - -- ------ -- --- ------------ DESIGN. ----- - - EX OUTLET PROTECTION EX 105' OF 36" RCP BARREL - --- ---- -- - - ---- - -- -_ INV IN=642.00 - - ._ _..------ - -- ----- - ----- - __ _ -_ - ---- - - - - -'---.._._..------ - - ------ - -----__ -- ---- " -- -------..._._------T- - ---- ----- --' --- - - _ _- _.. - ------ --- - --..-.__.---------._-.- _.-_- INV OUT=640.25 --- -- SLOPE=1.67% - --.- _._.- - '- - - ----- ---------- .-.._.. - - _ _ - ----_.-..__-•_•---1 ---- ---------- -----(00 -- I rr- 0 LO0 C o 0 CD o-- to In (a mm is 06 am (a cc; <a +00 11+00 12+00 13+00 14+00 UnD17AKITAI rnAI C. 1" On' VConi-A, Cr`AI C• 1" • w MAXIMUM • , FLOW.REFER TO SHEET C2.1 FOR AMENDED . I I I . I • b. Adequacy of all channels and pipes shall be verif' in the following manner: ` ' . EASEMENT V/W SWM (2) (a) Natural channels shall be analyzed the use of a PROVIDEDAT4E 65 SF EVATION ti r'`, two-year storm to verify that stormwater ill not overtop channel PRETREATMENT CELL: -., 656. FILTER MEDIA 36"f banks nor cause erosion of channel b or banks. 16'x24'x3 STONE -► "`' S63r2T24"E 199.57 " STORAGE TANK BIOFILTER ��� `• QzrR PRE -DEVELOPMENT = a.z6 cFs UNDERDRAIN. CLEANOUTS BIOFILTER % "' C- , • �.w 20' ON CENTER �r�■ OUTFACE .'a• ,t-: •, , � ,J /� �♦ 92YR POST -DEVELOPMENT - 6.83 CFS (� � ++!� � �,• ` , .. ' .� ... ...�. .. � J ON Q2YR POST -DEVELOPMENT = 8.83 CFS 5 Q2YR PRE -DEVELOPMENT = 9.28 CFS 1` ,• ` f 1 • ��•. �. FLOODING. 9VAC25-870-98 00 A. Downstream properties and waterways shall be protected from damages from localized flooding due to changes in runoff rate of flow and hydrologic characteristics, including, but not limited to, changes in volume, velocity, frequency, duration, and peak flow rate of stormwater runoff in accordance with the minimum design standards set out in this section. B. The 10-year postdeveloped peak rate of t1 site shall not exceed the 10-year predeveleped peak rate of runoff. Q10YR PRE -DEVELOPMENT = 27.36 CFS MAXIMUM Q10yR FLOW. REFER TO Q10YR POST -DEVELOPMENT = 19.49 CFS S Q10YR PRE -DEVELOPMENT = 27.36 CFS SHEET C2,1 FOR AMENDED QUANTITY CALCULATION SUMMARY. STREAM CHANNEL EROSION & FLOODING ANALYSIS A portion of the exisitng creek that will receive site runoff was visually inspected by Roudabush, Gale & Assoc. in order to obtain design information to evaluate existing conditions, as well as post -development conditions. The following observations/evaluations were made; 1. The creek appeared to be a rectangular channel with moderate to steep side slope banks. The banks varied in height but showed consistency of 2 feet or more. Water was present in the channel with a gentle flowing depth of 3-3.5 inches. The width of the creek channel varied between 4-5 feet. The creek appeared in good health and lined with natural earthen cover with some tall grass and weeds present. Soils appeared to be clay loam with natural erosion. 2. Calculations were run using the pre -development and post development conditions for the two and ten year storm events and were evaluated as such- 3. The bmp measures put forth for the proposed development provide a reduction in the runoff velocity exiting the site for both the two and ten year storm events. Projected values for the flow depth in the channel were obtained by forecasted linear trend methods and appear to show no threat of overtopping the banks of the existing channel. By reducing the velocity exiting the site, the measures will be providing additional relief of natural erosion of the exisiting channel banks, thus satisfying 9VAC25-870-97. 4. While the volume of flow will increase naturallty due to the project development, the rounoff from the site will be routed through multiple, complex design measures that will react to the increased volume and account for the peak intensity the hydrograph produces from the two and ten year storm events. No localized flooding is visually present at this time in the existing channel- The bmp measures will decrease the rate of flow that is exiting the site, reduce the velocity, and spread the peak intensity over a longer duration during a storm event, thus decreasing localized flooding satisfying 9VAC25-870-98. II I �� '� y,'> 1..,1•f ® i •a i °J , ^`•,• �'_•p ��-_ ,1 `'ti XT-� x-fli, .v Y' N y r a a _.x ••. Y r. / i i i Y �Sr ,....+ •',. ....�...+..� ..- i a .. _..y x � • 4r •� / ~•,ate a • ...ia _ !.3a',9.`�,. ': pp:?.. '•., -�^ - " • - "x" � .]t . ! y... y_ a. •... x.. j i i r r !.'', _! r r • .'x rr x a x • „ '•.• ,"�j. "d'aF�r:; �`. I i 11slr i ,1 Y,V/'�+•. ,,„, f✓ y , Y i'S. • . ' v ' a i• ... ' �, ni as''Y S a i a •- n "-" ' .. �J• ,` � 'y ' ��� � it ia'r i y • +i ,L � � i i i • i r s ' � / I L•` ''� � `, '��. � y J`i• Y Y i i i , y _ i N � i I 1f-.. ..,Nc i I• y I I \ •. PROPOSED CLEANOUTS `i•; ,% , ' '� . `••,, • , r ! 7 7 r PRE-TREATMENT CELLx/4W �t STONE DIAPHRAGM, � CLASS 1 RIPRAP • ..... v •, ' , . ' .' {i � rr ,y> f z � �• ` �" • r , 1 VEGETATIVE BUFFER ZONE FOR EXTENDED DETENTION BIORETENTION AND EXTENDED DETENTION PLAN VIEW J,/�� 'Y t. I' ', �.�,. • t>� 1 •. � yr• 30 0 30 60 90 SCALE: 1"=30' I a % 0 n = z� r' `V 2� T50 O a °' s oZ CO!)�0j QW Lj J_J Qy q 4Z �I tt " N¢ W W , O N V WQ 'K i(0I, x C7 a Lo 2 cD N fl CON ❑ V Q W U. OXVV ¢¢ jQW OJu CW 4� Luo �. Ho Z' o� W Wco co ZZ Z mW w Z 0 % a- REVISIONS COUNTY COMMENTS Feb 15, 2019 COUNTY COMMENTS April 15, 2019 FOR APPROVAL May 21, 2019 CONTOURS 2 FOOT [DATE October 22, 2018 SCALE AS SHOWN ,AyTH aF D Jim gart A ic. No. � 05� Y219 w� 0 �Ss1 L;11 WAL O O O T_ P4 Z O 2 U LLI z48 waO a�: Z < Cif) 'Z P4 y w �<(Ofl Q F z F J J O �©C) m a a OZO Wo U O W 06 FILE NUMBER 8053 SHEET C1.2 L BMP: SWM A Grass Channel Proposed Condition forTR-55 HSG RCN Area(ac) % RCNxArea 1 (Impervious) 98 2.52 70% 246.96 B (Managed Turf) 61 1.09 30% 66.49 B (Forest) 55 0.00 0% 0 TOTALS 3.61 87 RCN = 87 Site Rv (Rv Coefficients x Land Cover %) Managed Turf B Soils, Rv = 0.06 Forest B Soi Is, Rv = 0.00 Impervious, Rv = 0.66 Rv = 0.72 Other Design Requirements Meets Requirement? Comments Yes Channel sideslopes 3HAVorflatter Yes 3H:1V Maximum drainagearea <5 acres Yes 3.61 Longtitudinal slope<4% Yes 4.00% 10-year storm contained within channel Yes 0.3 feet freeboard for 10-year storm Yes 0.43 feet provided A ell! IkVAVAVAVAVAVAVAVAVAVAVAVAVAVAkVATA- /�ppggY000�p��qpYwp I FI It TAT AAAAA "'1 04 .r Table 3.3: Maximum Permissible Velocities for Grass Channels Erosion Easily Eroded Cover Type Slope (%) Resistant Soils Soils (ft./sec.) ft.rsec. 6 1 4.5 Bermudagrass 0-5 Kentucky bluegrass Reed Canarygrass 0-5 5 3.8 Tall fescue Bermudagrass 5-10 5 3.8 Kentucky bluegrass Reed Canarygrass 5-10 4 3 Tall fescue Grass -legume mixture 0-5 4 3 5-10 3 2.3 Kentucky bluegrass Reed Canarygrass > 10 3 2.3 Tall fescue Red fescue 0-5 2.5 1.9 DRAINAGE AREA = 3.61 AC CN= 87 TC= 14.5 MIN. n=0.20 (SHORT GRASS) Q(1) = 5.41 CFS Q(2) = 7.03 CFS Q(10) = 12.27 CFS MAX. FLOW VELOCITY (1YR.) = 0.97 FT/S MAX. FLOW DEPTH (1YR.) = 0.69' MAX. FLOW VELOCITY (2YR.) = 1.05 FT/S MAX. FLOW DEPTH (2YR.) = 0.80' MAX. FLOW VELOCITY (10YR.) = 1.25 FT/S MAX. FLOW DEPTH (1 OYR.) = 1.07' DESIGN DEPTH =1.50' LENGTH = 110' WIDTH = 6' MIN. SLOPE = 4.0% Sources: Virginia E&S Control Handbook, 1992; Ree, 1949; Temple at al, 1967; NOVA, 2007 Table 3.5. Suggested Spring Maintenance Inspections/Cleanups for Grass Channels Activity Add reinforcement planting to maintain 90%turf cover. Reseed any salt -killed vegetation. Remove any accumulated sand or sediment deposits behind check dams. Inspect upstream and downstream of check dams for evidence of undercutting or erosion, and remove and trash or blockages at weep holes. Examine channel bottom for evidence of erosion, braiding, excessive ponding or dead grass. Check inflow points for clogging and remove any sediment. Inspect side slopes and grass filter strips for evidence of any rill or gully erosion and repair - Look for any bare soil or sediment sources in the contributing drainage area and stabilize immediately. Channel Report Hydraflow Express Extension for Autodesk®ANOCAea Chll 30®byA esk, Inc. GRASS CHANNEL (2-YR) Trapezoidal Bottom Width (ft) = 6.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.50 Invert Elev (ft) = 659.00 Slope (%) = 4.00 N-Value = 0.200 Calculations Compute by: Known Q Known Q (cfs) = 7.03 Elev (ft) ee1.00 660.50 660.00 659.50 669.00 Section FMsy, Apr 1=2 Highlighted Depth (ft) = 0.80 Q (cis) = 7.030 Area (sgft) = 6.72 Velocity (ft/s) = 1.05 Wetted Perim (ft) = 11.06 Crit Depth, Yc (ft) = 0.33 Top Width (ft) = 10.80 EGL (ft) = 0.82 Channel Report Hydralbw Express Extension for Autodeckc AetoCitM Chll 3M by Aptodeni Inc. GRASS CHANNEL (10-YR) Trapezoidal Bottom Width (ft) = 6.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.50 Invert Elev (ft) = 659.00 Slope (%) = 4.00 N-Value = 0.200 Calculations Compute by: Known Q Known Q (cfs) = 12.27 Depth (ft) Elev (ft) 2.00 ee1.00 1.50 660.50 1.00 660.00 - 0.50 659.50 0.00 659.00 658.50 -0.50 0 2 4 6 8 10 12 14 16 18 20 Reach (ft) Section BMP: SWM B Biofilter - LEVEL 2 Runoff Coefficients (Rv) 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 Proposed Condition forTR-55 HSG RCN Area(ac) % RCNxArea 1 (Impervious) 98 2.52 70% 246.96 B (Managed Turf) 61 1.09 30% 66.49 B (Forest) 55 0.00 0%d 0 TOTALS 3.61 87 RCN = 87 Site Rv (Rv Coefficients x Land Cover %) Managed Turf BSoils, Rv = 0.06 Forest B Soi Is, Rv = 0.00 Impervious, Rv = 0.66 Rv = 0.72 Treatment Volume, Tv (Spec. No. 9, Table 9.4) Tv = [((1.25 in) x (Rv) x (A)) _ 121 - vol ume reduced by upstream BMP Dra i na ge Area, A = 157,252 sf Upstream Vol ume Treated = 7,585 cu ft *per RRM 3.0 Column E Treatment Volume, Tv = 4,267 cu ft Required Treatment Volume - Storage Depth Storage Depth (ft) Void Ratios Pondi ng Depth= 0.50 1.00 Depth of Media Filter= 3.50 0.25 Stone Sump Depth= 1.25 0.40 Treatment Volume, Tv = 1.88 ft Provided Treatment Volume - Surface Area Minimum Required Surface Area= 2,275.71 sf Surface Area Provided= 2,280.00 sf Fore bay Volume Required ForebayVolume= 640 cf Volume Provided= 645 cf WATER TABLE NOTE: THE LOCATION OF THE GRASS CHANNEL AND BIOFILTER DESIGN CONTAINS SOIL CLASSIFICATION 4E ASHE LOAM AND HAS A MINIMUM DEPTH TO THE WATER TABLE OF MORE THAN 80" OR 6.67' BELOW GRADE. THE MOST RESTRICTIVE DESIGN FOR THE SWM FACILITIES WOULD BE THE EXCAVATED MATERIAL TO THE BIOFILER BOTTOM. THIS DESIGN PROVIDES MORE THAN THE RECOMMENDED 2' OF SEPARATION BETWEEN THE MEDIA BED AND WATER TABLE AND POSSES NO FORESEEABLE CONCERN WITH GROUNDWATER CONTAMINATION WITHIN THE FILTER MEDIA. FMry, Apr 1=2 Highlighted Depth (ft) = 1.07 Q (cis) = 12.27 Area (sgft) = 9.85 Velocity (ft/s) = 1.25 Wetted Perim (ft) = 12.77 Crit Depth, Yc (ft) = 0.47 Top Width (ft) = 12.42 EGL (ft) = 1.09 Depth (ft) 2.00 1.50 1.00 0.50 0.00 658.50 -0.50 0 2 4 6 8 10 12 14 16 18 20 Reach (ft) 6"CLEANOUT 3" HARDWOOD BARK MULCH BOTTOM ELEV 654.75 42" BIOFILTER MIX BOTTOM ELEV 651.25 3" NO. 8 STONE TOP ELEV 651.00 15" NO. 57 STONE 24"NYLOPLAST BASIN WITH DOME GRATE TOP = 655.50 RAMP SOIL TO LIP OF OVERFLOW STRUCTURE MIN SLOPE 3:1 BOTTOM OF BIORETENTION BASIN 655.00 ELEV. 649.75 PVC UNDERDRAIN FABRIC OR EQUIVALENT. TO BE 2' WIDE CENTERED ON UNDERDRAIN NOTES 1. 42" BIOFILTER MEDIA DEPTH SHALL BE THE MINIMUM DEPTH AFTER A SETTLING PERIOD OF THREE DAYS. 2. FILTER MEDIA MUST BE SUPPLIED BY AN APPROVED VENDOR SWM-B - LEVEL 2 BIORETENTION ALONG UNDERDRAIN Nn crnl F VA DCR STORMWATER DESIGN SPECIFICATION NO. 9 Table 9.7. Bioretention Material Specifications BIORETENTION Material Specification Notes Filter Media to contain: The volume of filter media based on 110% Filter Media • 80% - 90% sand of the plan volume, to account for settling Composition 0 10%-20% soil fines or compaction. 3%-5% organic matter Available P between L+ and M per Filter Media DCR 2005 Nutrient Management The media should be certified by the Testing Criteria. supplier. Mulch Layer Use aged, shredded hardwood bark Lay a 2 to 3 inch layer on the surface of the mulch or stable coarse compost. filter bed. Alternative Use river stone or pea gravel, ooir and Lay a 2 to 3 inch layer of to suppress weed Surface Cover jute matting, or turf cover. growth. Loamy sand or sandy loam texture, Top Soil with less than 5% clay content, pH 3 inch surface depth. For Turf Cover corrected to between 6 and 7, and an organic matter content of at least 2%. Use anon -woven geotextile fabric with Apply only to the sides and directly above Geotextile/Liner a flow rate of > 110 gal./min./sq. ft, the underdrain. For hotspots and certain (e.g., Geotex 351 or equivalent) karst sites only, use an appropriate liner on bottom. Choking Layer Lay a 2 to 4 inch layer of sand over a 2 inch layer of choker stone (typically #8 or #89 washed gravel), which is laid over the underdrain stone. Stone Jacket for Underdrain 1 inch stone should be double -washed 12 inches for the underdrain; and/or Storage and clean and free of all fines (e.g., 12 to 18 inches for the stone storage layer, Layer VDOT #57 stone). if needed Use 6 inch rigid schedule 40 PVC pipe Lay the perforated pipe under the length of Underdrains, Unda (or equivalent corrugated HDPE for the bioretention cell, and install non- outs, and CleanObservation micro-b[oretention), with 3/8-inch perforated pipe as needed to connect with perforations at 6 inches on center; the storm drain system. Install T's and Ys Wells position each underdrain on a 1% or as needed, depending on the underdrain 2% slope located nor more than 20 feet configuration. Extend cleanout pipes to the from the next pipe. surface with vented caps at the Ts and Ys. Plant one tree per 250 square feet (15 Establish plant materials as specified in the feet on -center, minimum 1 inch landscaping plan and the recommended caliper). plant list. Shrubs a minimum of 30 inches high In general, plant spacing must be sufficient planted a minimum of 10 feet on- to ensure the plant material achieves 80% Plant Materials center. cover in the proposed planting areas within Plant ground cover plugs at 12 to 18 a 3-year period. If seed mixes are used, they should be from inches on -center; Plant container- a qualified supplier, should be appropriate grown plants at 18 to 24 inches on- for stormwater basin applications, and center, depending on the initial plant should consist of native species (unless the size and how large it will grow. seeding is to establish maintained turf). • General Filter Media Physical Composition. The mineral soil texture of the bioretention soil mix should be loamy coarse sand with no more than 10% clay, no more than 20% silt + clay and at least 75% of the sand fraction should be coarse or very coarse sand. • To allow for appropriate Cation Exchange Capacity (CEC) and nutrient removal, the mix should contain at least 10% soil fines (silt + clay) while meeting the overall texture specification above. The particle size analysis must be conducted on the mineral fraction only or following appropriate treatments to remove organic matter before particle size analysis. The Filter Media should contain 3% to 5% organic matter by conventional Walkley-Black soil organic matter determination method or similar analysis. Soil organic matter is expressed on a dry weight basis and does not include coarse particulate (visible) components Table 9-8- Suooested Annual Maintenance Activities for Bioretention Maintenance Tasks Frequency • Mowing of grass filter strips and bioretention turf cover At least 4 times a year • Sot weeding, erosion repair, trash removal, and mulch raking Twice during growing season It Add reinforcement planting to maintain desired the vegetation density It Remove invasive plants using recommended control methods As needed It Stabilize the contributing drainage area to prevent erosion Spring inspection and cleanup p 9 P p • Supplement mulch to maintain a 3 inch layer Annually It Prune trees and shrubs It Remove sediment in re -treatment cells and inflow points Once every 2 to 3 years It Replace the mulch layer Every 3 years BMP PRACTICE DOCUMENTATION NOTE: CONTRACTOR SHALL NOTIFY TIMMONS GROUP FOR PRIOR TO COMMENCEMENT OF CONSTRUCTION OF BMP PRACTICES. A PRECONSTRUCTION MEETING BETWEEN THE DEVELOPER, CONTRACTOR, ENGINEER, INSPECTOR, AND MANUFACTURER IS HIGHLY RECOMMENDED PRIOR TO INSTALLATION OF THESE SMW PRACTICES TO ENSURE THESE PRACTICES ARE NOT ONLY INSTALLED CORRECTLY, BUT ALSO PROPERLY DOCUMENTED THROUGHOUT CONSTRUCTION. IT IS THE CONTRACTORS SOLE RESPONSIBILITY TO DOCUMENT THE INSTALLATION OF THESE PRACTICES. IF THEY PROCEED WITHOUT DOING SO, IT IS DONE AT THEIR OWN RISK. CONTRACTOR SHALL TAKE NOTES, PICTURES, AND MEASUREMENTS OF ALL SUB STRATA LAYERS WITHIN THE BIORETENTION FACILITY DURING CONSTRUCTION THAT CANNOT BE SURVEYED OR VERIFIED POST CONSTRUCTION. IT IS HIGHLY RECOMMENDED TO USE THIS LEVEL OF DETAIL FOR ALL SWM MEASURES BEING INSTALLED IN ADDITION TO THIRD PARTY INSPECTIONS/REPORTS. WITHOUT DOCUMENTING TO THIS LEVEL OF DETAIL, THE CONTRACTOR RUNS THE RISK OF DIGGING THE FACILITIES UP POST CONSTRUCTION TO PROVE THE CORRECT SECTIONS AND SPECIFICATIONS WERE INSTALLED. TOP OF BIORETENTION BASIN 655.00 3" HARDWOOD BARK MULCH BOTTOM ELEV 654.75 42" BIOFILTER MIX BOTTOM ELEV 651.25 3" NO. 8 STONE TOP ELEV 651.00 15" NO. 57 STONE SCHEDULE40 PVC UNDERDRAIN ELEV. 649.75 MIRAFI 140N FILTER FABRIC OR EQUIVALENT. TO BE 2' WIDE CENTERED ON UNDERDRAIN GEOTEXTILE TO MEET TABLE 9.6 OF THE BIORETENTION MATERIAL SPECIFICATIONS FOR GEOTEXTILE/LINERS SWM-B- LEVEL 2 BIORETENTION CROSS SECTION FLOW FROM FOREBAY PRETREATMENT CELL #57 STONE 1:1 SIDE MARAFI140N7 SLOPE FILTER FABRIC OR EQUIVALENT PRETREATMENT II - DISSIPATER CELL DETAIL FOR LEVEL 2 BIOFILTER REQUIREMENT No Scale Pre -Construction Meeting ❑ Pre -construction meeting with the contractor designated to install the bioretention practice has been conducted. ❑ Identify the tentative schedule for construction and verify the requirements and schedule for interim inspections and sign -off. ❑ Subsurface investigation and soils report supports the placement of an bioretention practice in the proposed location. ❑ Impervious cover has been constructed/installed and area is free of construction equipment, vehicles, material storage, etc. ❑ All pervious areas of the contributing drainage areas have been adequately stabilized with a thick layer of vegetation and erosion control measures have been removed. ❑ Area of bioretention practice has not been impacted during construction. ❑ Stormwater has been diverted around the area of the bioretention practice and perimeter erosion control measures to protect the facility during construction have been installed. . Excavation ❑ Compare the bioretention surface and invert design elevations with the actual constructed elevations of the inflow and outlet inverts and adjust design elevations as needed. ❑ Area of bioretention excavation is marked and the size and location conforms to plan. ❑ If the excavation area has been used as a sediment trap: verify that the bottom elevation of the proposed stone reservoir is lower than the bottom elevation of the existing trap. ❑ For Level 2 bioretention, ensure the bottom of the excavation is scarified prior to placement of stone. ❑ Subgrade surface is free of rocks and roots, and large voids. Any voids should be refilled with the base aggregate to create a level surface for the placement of aggregates and underdrain (if required). ❑ No groundwater seepage or standing water is present. Any standing water is dewatered to an acceptable dewatering device. ❑ Excavation of the bioretention practice has achieved proper grades and the required geometry and elevations without compacting the bottom of the excavation. ❑ Certification of Excavation Inspection: Inspector certifies the successful completion of the excavation steps listed above. Filter Layer, Underdrain, and Stone Reservoir Placement ❑ All aggregates, including, as required, the filter layer (choker stone & sand), the stone reservoir layer or infiltration sump conform to specifications as certified by quarry. ❑ Underdrain size and perforations meet the specifications. ❑ For Level 2 installations: placement of filter layer and initial lift of stone reservoir layer aggregates with underdram or infiltration sump, spread (not dumped) to avoid aggregate segregation; or ❑ Impermeable liner, when required, meets project specifications and is placed in accordance with manufacturers specifications. ❑ Sides of excavation covered with geotextile, when required, prior to placing stone reservoir aggregate; no tears or holes, or excessive wrinkles are present. ❑ Placement of underdrain, observation wells, and underdrain fittings (45 degree wyes, cap at the upstream end, etc.) are in accordance with the approved plans. ❑ Elevations of underdrain and outlet structure are in accordance with approved plans, or as adjusted to meet field conditions. ❑ Placement of remaining lift of stone reservoir layer as needed to achieve the required reservoir depth. ❑ Certification of Filter Layer and Underdrain Placement Inspection: Inspector certifies the successful completion of the filter layer and underdrain placement steps listed above. Bioretention Soil Media Placement ❑ Soil media is certified by supplier or contractor as meeting the project specifications. ❑ Soil media is placed in 12-inch lifts to the design top elevation of the bioretention area. Elevation has been verified after settlement (2 to 4 days after initial placement). ❑ Side slopes of ponding area are feathered back at the required slope (no steeper than 3F1:1 V). ❑ Certification of Soil Media Placement Inspection: Inspector certifies the successful completion of the soil media steps listed above. Pretreatment and Plant Installation ❑ Placement of energy dissipators and pretreatment practices (forebays, gravel diaphragms, etc.) are installed in accordance with the approved plans. ❑ Riser, overflow weir, or other outflow structure is set to the proper elevation and functional; or. ❑ External bypass structure is built in accordance with the approved plans. ❑ Appropriate number and spacing of plants are installed in accordance with the approved plans. ❑ All erosion and sediment control practices have been removed. ❑ Follow-up inspection and as -built survey/certification has been scheduled. ❑ GPS coordinates have been documented for all bioretention practice installations on the parcel. LNLTU OpIEREMYJJ/JJ/ L. FOX Lic. No. 60786 06/14/22 M E CD M O N 6 N C > E w w E y LL o 3 ow- w 0 `m IY r U t M d J U o 0 w J -vi d C) N to N 7 (7 W N Ili- it- 3: 0 U'x u- ix 0a =v L _ C N = U > F c N 0 M N T M a- CDW M O x c� 0 H 0 w Lu U U Q Z O 0 N Z 0 LM LU Z w O a_ OV N Z 0 O Z U O w vt o_ of N > w uJ DATE 0410512022 DRAWN BY J. FOX DESIGNED BY J. FOX CHECKED BY C. SHIFFLETT SCALE M i U) IJ-I z � Q � 0^ Lf) LU 1=.L Q �j z O � z N > MLLJZ J < W U co w w co 0aa _ J LL W O Q 1 =) 2:/ LU Q Q J O Q O JOB NO. 47010 SHEET NO. C2.0 0 c L PLAN VIEW OF PROPOSED GRASS CHANNEL IIC STORMWATER MANAGEMENT & BIORETENTION FACILITIES SCALE: 1" = 20' ` \ ARRANGE AS -BUILT \ \ OUTFALL RIPRAP AS NECCESSARY TO V/W SWM EASEMENT \` TMP 55E-01-22 A \ \ \ ACHIEVE OUTLET MARCH MOUNTAIN PROPERTIES LLC PROTECTION AT DB 5108 PG 304 \ \ CHANNEL INLET \ 100'WPOBUFFER 668 \ SWM A - 110' LONG 6' WIDE \ 75' STREAM BUFFER LOT ENCROACHMENT \ WETLANDS TRAPEZOIDAL GRASS VARIATION APPROVAL (0310612019) \ CHANNEL @ 4.0% \ \\ ! SEE DETAIL SHEET C2.0 \ I \ \ APPROVED LIMITS OF DISTURBANCE \ ` \ \ *% � � FOR WP0201800077 ENSURE SILT FENCE IS STILL INTACT AND OPERATIONAL FROM ORIGINAL PLAN. REPLACE OR \ \ REPAIR AS NEEDED DOWNSTREAM PRIOR TO BIOFILTER INSTALLATION. \ PROPOSED FENCE �\ \ TIE TO EXISTING GROUND @ 2:1 SLOPE AS INDICATED ON APPROVED WPO. STABILIZE WITH LOW MAINTENANCE VEGETATIVE COVER \ N h CROP PER VESCH SPEC 3.32 TABLE 3.32-D) W \ \6 6S 646 \\ \ OTHER THAN GRASS. (I.E. SEASONAL NURSE 6S6 6Sq \2 0 \ \ /\ TMP 55E-01-32-89 ` / PRE-TREATMENT FOREBAY W W W W 6 \ 24" NYLOPLAST BASIN i CRAIG ENTERPRISES INC CLASS Al RIP -RAP W W W W W W Ss \\ WITH DOME GRATE TOP @ 655.50 & DB 5625 PG 57 / VOLUME = 645 CF p W r W \\� 12" SCH 40 PVC OUTLET TO ED POND \ p p W W W y SEE DETAIL SHEET C2.0 `\ \ PRE-TREATMENT #57 STONE \\ W W W \\\ STONE OVERFLOW ///// //// \ \ DIAPHRAGM @ 655.50 �� q W W W W W r \ WEIR INTO EXISTING \ SEE DETAIL SHEET C2.0 �656 6S W W W W \\ BASIN @ 655.50 \ SWM B - LEVEL II 6" DIAMETER COBBLE @ 1' DEEP BIORETENTION FACILITY q ro L= 8' / TMP 55ESURFACE AREA = 2,280 SF 6' \ CRAIG ENTERRPRISESPRISES INC W= TAPER TO i 0' TOP OF M ULCH = 655.00 \ \ j DB 5613 PG 457 / SEE DETAIL SHEET C2.0 rob 6" SCH 40 PERFORATED UNDERDRAIN SYSTEM WITH CLEANOUTS 20' ON CENTER \ I SEE DETAIL SHEET C2.0 \ TMP 55E-01-32-91 CRAIG ENTERPRISES INC / / / / / �U6U6 j \ \ a \ \\ \ DB5566PG 156 \\' TMP 55E-01-32-92 \ \ ORCHARD CORP. DB 5612 PG 294 \ I \ TMP 55E-01-32 A MARCH MOUNTAIN PROPERTIES LLC DB5208PG362 \\ EXISTING TOPOGRAPHY REPRESENTS 2020 FIELD SURVEY BY ROUDABUSH, GALE & ASSOCIATES, INC. y ` \ \ �i u �`-------------- = `---- BISHOPGATE LANE ,, ;�, / / /� p SCALE 1"=20' 00 w 0 20' 40' LANDSCAPE PLAN I��_ •� I�I�x •son!-.iY All IWORElM �► P.' . �'�•'���`i�t ip#w►;� 1 1 j 1 r, j � 1 1 � PLANT LIST BOTANICAL DESIGNATION QUANTITY COMMON NAME SIZE SPACING NAME BN 2 BETULA NIGRA HERITAGE RIVER 6' HT. 25' O.C. "HERITAGE" BIRCH CO 8 CEPHALANTHUS BUTTONBUSH 18-24" HT. 10' O.C. OCCIDENTALIS CS 7 COMUS SERICEA BAILEY RED TWIG 18-24" HT. 8' O.C. "BAILEY[" DOGWOOD HV 15 HAMAMELIS COMMON 24-36" HT. 15' O.C. VIRGINIANA WITCHHAZEL HM 15 HIBISCUS CRIMSON -EYED 1 GALLON 3' O.C. MOSCHEUTOS ROSE -MALLOW CONTAINER LLEX RED SPRITE RSW 19 VERTICILLATA 18-24" HT. T O.C. "RED SPRITE" WINTERBERRY LLEX JIM DANDY JDW 6 VERTICILLATA "JIM WINTERBERRY 18-24" HT. 5' O.C. DANDY" VD 10 VIBURNUM ARROWWOOD 24-36" HT. 10, O.C. DENTATUM VIBURNUM ERNST CONSERVATION SEEDS, INC. ERNMX-180-2 MIX 1 0.5 LBS SOUTHEAST RAIN GARDEN MIX OR EQUAL WATER QUALITY CALCULATIONS VA DCR SWPP Performance Based Water Quality Calculation Procedure Project: OTV-Block 32 Locality: Albemarle Co. Date: 4/1/2022 13:45 Step 1 Determine the applicable area (A) and the post -developed impervious cover ([post). Applicable area (A) = I s.f. or 10.380 acres Post -development impervious cover: structures = parking lot = roadway = impervious = or 0.000 acres or 0.000 acres or 0.000 acres or 5.500 acres or 0.000 acres or 0.000 acres Total = 239580 s.f. or 5.500 acres Ipos( = (total post- development impervious cover - A) x 100 F 539/6 Step 2 Determine the average land cover condition ([watershed) or the existing impervious cover (Iexisting)- Average land cover condition (Iwats bed): Ifthe locality has determined land cover conditions for individual watersheds within its jurisdiction, use the watershed specific value determined by the locality as Iwatershed. 0 watershed ° Otherwise, use the Chesapeake Bay defauk value: watershed 0 ° Iwatersbed= 16% Existing impervious cover (I,; 1,„ : Determine the existing impervious cover of the development site ifpresent. Pre -development impervious cover: structures = parking lot = roadway = other Concrete or 0.000 acres or 0.000 acres or 0.000 acres or 0.000 acres or 0.000 acres or 0.000 acres Total = 0 s.f. or 0.000 acres Ie;isting = (total existing impervious cover - A) x 100 = 0% * The area should be the same as used in STEP 1. Step 3 Determine the appropriate development situation. The site information detennarned in STEP 1 and STEP 2 provide enough information to detert®e the appropriate development situation under which the performance criteria will apply. Check U the appropriate development situation as follows: No Situation 1: This consists of land development where the existing percent Knipe vious cover (leas, Ind is less than or equal to the average land cover condition (Iwatershed) and the proposed nnprovements will create a total percent nnpervious cover (Ipost) which is less than or equal to the average land cover condition ([watershed). False Ipost[_ post 53% s I„,ta„hen 16% Yes Situation 2: This consists of land development where the existing percent impervious cover (lexi,lay is less than or equal to the average land cover condition (Iwatershed) and the proposed improvements will create a total percent impervious cover (Ipost) which is greater than the average land cover condition ([watershed). True IaxbUagr 0%7!9 "trash sit r 16% and True Ipo,t 53% > Iw,texakea 16% No Situation 3: This consists of had development where the existing percent amper 6ous cover (lexi,iag) is ¢neater than the average land cover condition ([watershed). False Iexist a6� > I„wta„had 16% No Situation 4: This consists of land development where the existing percent napervious cover (lexamd is served by an existng stomrsvater management BMP(s) that addresses water quality. Ifthe proposed development meets the criteria for development Situation 1, than the low density development is considered to be the BMP and no pollutant removal is required. The calculation procedure for Situation 1 stops here. If the proposed development meets the criteria for development Situations 2, 3, or 4, then proceed to STEP 4 on the appropriate worksheet. VA DCR SWPP Performance Based Water Quality Calculation Procedure SIT uanoN2 True Iesruma 0% SIv.vxxbail 10% Pmjacf 07/431ock 32 and Locality: Albemarle Co. True 1pran 16% Date: 01Apr.22 SITUATKIN3 Summary ofSduation 2 criere: from calcubtion procedure STEP l thnu STEP 3, Workshed l: False 1..1.1.9 0% lwatenh. 16% Area 10 38 ac. tons 53% Iwatmhed= 16% I roa t ug 0% SrruATrnN4 False Ivasn"e BMP CURRMTLYIN i PLACE? NO Step 4 Determine the relative pre -development pollutant load (L,.). Based on Existing IMP=Mons Corer 1 Lpre(exis„"a) [0 05 + (0.009 x lwam )] x A x 2.28 (Equation 5-16) where. Lpre(mnoxio = relative pre-devebpmeNtotalphosphmous bad (pounds peryear) Ir,ra, = Eningvteimpavinuscwu(FB®tapressdi"whnlenm"bm) A = applicable area (acres) Lpre(e:na"e) _ [0.05 + (0.009 x 0% )1 x 1038 x 2 28 1.18 pounds per year 2 Lpre(w„enheo - [0.05 + (0.009 x Iwlermea)] x A x 2.28 (Equation 5-16) where: Lp„(,w„rsh,s =relative pre -development tomlphosphorous load (pounds per year) tnomseheb = avawlmdwvvwaaim for spmficwaes6d alodiry ortheamViske Bay dd Itvioeofl6%(pasmu Wressdwwholeoumars) A = applicable area (acres) Linvaroenea u = [0.05 + (0.009 x 16% )I x 10.38 x 2.28 pounds per yew Step 5 Determine the relafive post development pollutant load (I'P"„)- LPa„ _ [0.05 + (0.009 x Ipaa)] x A x 2.28 (Equation S21) where: LpPu = relative post -development totalphospinrom load (pounds per year) Ipeu = post -development impervious cover (percent expressed in whole numbers) A = applicable area (acres) LPo„ = [0.05 + (0.009 x 53% )l x 10.38 x 2.28 = 1247 pounds per year Step 6 Determine the mrlative pollutant removal mguirement(RR). RR = LP., - (0.9 x Lpm(miui,d) RR = 12.5 - 1.1 RR= 11.40 pounds per year or RR = Lpou-Lpafvme :tied) RR = 12.5 - 4.6 RR= 7.88 pounds per year Use RR= 7.(i8 (lesservahne) Step 7 Identify best management practice (BMF) for the site. 1. Deter ati ne the required pollutant removal efficiency for the site: EFF = (RR - LpPu ) x 100 (Equation 5-22) Where: EFF = required polluitant removal efficiency RR = polloant removal requirernem (pounds per year) LpPu = relative post -development total phosphorous load, Equation 5-21 (pounds per year) 2. select BMP(s) from Table 5-14 and locate on the site: Drainage Impervious Type Eficiency Area (s f) Amer (s f) Description_ BMP1: BMP2: BMP3: BMP4: BMP5: Step 4 Determine the relative pre -development pollutant load (L,.). Based on Existing IMP=Mons Corer 1 Lpre(exis„"a) [0 05 + (0.009 x lwam )] x A x 2.28 (Equation 5-16) where. Lpre(mnoxio = relative pre-devebpmeNtotalphosphmous bad (pounds peryear) Ir,ra, = Eningvteimpavinuscwu(FB®tapressdi"whnlenm"bm) A = applicable area (acres) Lpre(e:na"e) _ [0.05 + (0.009 x 0% )1 x 1038 x 2 28 1.18 pounds per year 2 Lpre(w„enheo - [0.05 + (0.009 x Iwlermea)] x A x 2.28 (Equation 5-16) where: Lp„(,w„rsh,s =relative pre -development tomlphosphorous load (pounds per year) tnomseheb = avawlmdwvvwaaim for spmficwaes6d alodiry ortheamViske Bay dd Itvioeofl6%(pasmu Wressdwwholeoumars) A = applicable area (acres) Linvaroenea u = [0.05 + (0.009 x 16% )I x 10.38 x 2.28 pounds per yew Step 5 Determine the relafive post development pollutant load (I'P"„)- LPa„ _ [0.05 + (0.009 x Ipaa)] x A x 2.28 (Equation S21) where: LpPu = relative post -development totalphospinrom load (pounds per year) Ipeu = post -development impervious cover (percent expressed in whole numbers) A = applicable area (acres) LPo„ = [0.05 + (0.009 x 53% )l x 10.38 x 2.28 = 1247 pounds per year Step 6 Determine the mrlative pollutant removal mguirement(RR). RR = LP., - (0.9 x Lpm(miui,d) RR = 12.5 - 1.1 RR= 11.40 pounds per year or RR = Lpou-Lpafvme :tied) RR = 12.5 - 4.6 RR= 7.88 pounds per year Use RR= 7.(i8 (lesservahne) Step 7 Identify best management practice (BMF) for the site. 1. Deter ati ne the required pollutant removal efficiency for the site: EFF = (RR - LpPu ) x 100 (Equation 5-22) Where: EFF = required polluitant removal efficiency RR = polloant removal requirernem (pounds per year) LpPu = relative post -development total phosphorous load, Equation 5-21 (pounds per year) 2. select BMP(s) from Table 5-14 and locate on the site: Drainage Impervious Type Eficiency Area (s f) Amer (s f) Description_ BMP1: BMP2: BMP3: BMP4: BMP5: Orris Swale 1 32 1 1572516 JIM7712 BMPA BMPB BMPC BMPD BMPE Biofilter N 1572516 IM7712 ExtendedD 25 2949012 239580 3. Determine the pollmant bad entering the proposed BMP(s): La,B = [0.05 + (0.009 x Ixnap)] x At,,,,, x 2.28 (Equation 5-23) Where : Le, = mlativepost-dewiDpme°ttotalphosphmom bad enteringproposed BMP(poundsperyen) Imp = post -development percent impervious cover to proposed BMP (percent expressed in Aole numbers) ApppaMp = drainage area to proposed BMP (acres) Lsoa,l = [0.05 + (0.009 x 70% )1 x 3.81 x 2.28 = 5,58 pounds per year L� = [0.05 + (0.009 x 70% )1 x 3.61 x2.28 = 5.58 pounds per year Lucia, = [0.05 + (0.009 x 81% )] x 6.77 x 2.28 = 12M pounds per year Laxo, = [0.05 + (0.009 x 0% )1 x 0,00 x2.28 = 0.00 ponds per year La,Bf = [0.05 + (0.009 x 0% x 0.00 x 2.28 4. Calculate the polhtam bad removed by the proposed BMP(s): L_r_, - E'YiMp x rotor, (Equation 5-24) where: a,i ,,a = post-devebpmetrt totalphosphoro s bad removed by proposed BMP (pounds per year) Effaw= po@rtantra°ovalelliciencyofBMP(expressed udecialkamt) Law = relative post -development toalphosphorou bad enteringproposed BMP. Equation 5-23 poundsper yen) Lremo v,,,xvr 1.79 Pounds per year removed Lremo v,,a,V2 5.02 Pounds per year removed L,,aa.,,,.NP3 3.01 Pounds per year removed Lrvm-u,,vpr 0.00 Pounds per year removed LwmovaaaArpr 0.00 Pounds peryear removed 5. Calculate the total pollution bad removed by the BMP(s): I.-invvdrtatn = LrmuvedBM1@1+L_-eF3x 2+L.®orvvetw3+...(Equation 5-25) where: I.,®vvr;,om = total potiaant bad ren>ved by proposed BMPB (pounds per year) L,muvaiab@n - po@IIant bad removed by proposed BMP No. 1, Equation 5-24 Lrmo,d 2 = polhdant bad removed by proposed BMP No. 2, Equation 5-24 Lnaar, , = polhipa t bad removed by proposed BMP No. 3, Equation 5-24 Lrema vdArtal 9.83 Total Pounds per year removed 6. Verify compliance: 4emmad4ebl > RR Lrmov,donl= 9,83 Total Pounds per year removed Req'd Remoel= 7.88 Total Pounds per year removed OK, Removal Rate Exceeded IIC STORMWATER MANAGEMENT VV/11 Cr[ 1, WAIV I I I T I IIJIVJ 9VAC25-870-97 STREAM CHANNEL EROSION: Q2 R PRE-DEV - 9.28 CFS (WPO-2018-00077) Q' 2YR POST-DEV = 7.05 CFS OK Q' 2YR POST-DEV < Q2YR PRE-DEV 9VAC25-870-89 FLOODING: Q10YR PRE-DEV = 27.36 CFS (WPO-2018-00077) Q' 10YR POST-DEV = 9.50 CFS OK POST -DEVELOPED Q10 <_ PRE -DEVELOPED Q10 ALTU Op (EREMY L. FOX Lic. No. 60786 06114122 M E O � O N V, N C > E w ° E Lu UM 3 0 U. O w 0 m K ly t M Q JUto W i Ui ce:dCry t`r Ur N (7 W w� 30NxLL -aid 04 led, _ N Ito N U > M F c n O Co N � M co a � � H F_ z Z W O E a_ OV of W Z) 0 O Z U O w m c- o N w f DATE 0410512022 DRAWN BY J. FOX DESIGNED BY J. FOX CHECKED BY C. SHIFFLETT SCALE AS SHOWN ro z U J U)L O C~ z Q W Q a O U Q z �z Q N > M LE a of 2 : UW w Om� J LL LLI o J a z z W o Q (D Q LLLI > 1� o U-) 0 O JOB NO. 47010 SHEET NO. C2.1 0 c a ra c SCALE 1"=20' 00 0 20' 40' L AM