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WPO201300071 Calculations 2013-11-21
STORMWATER MANAGEMENT REPORT Collins Medical Center Addendum biLMQ AND ASSOCIATES INC REFLECTING TOMORROW 1561 Commerce Road, Suite 401 Verona, VA 24482 540-248-3220 Prepared by: Balzer & Associates Project No: S0900017 October 14, 2009 Resubmitted December 13, 2013 Adequate Channel As described herein, a closed storm sewer system collects the majority of the stormwater run-off from the project site. It is our assumption that this pipe is associated with a regional stormwater pipe system. In accordance with the Virginia Erosion & Sediment Control Regulations, VR 625-02-00, § 1.5 Minimum Standards, Section 19.c(3), the proposed site design provides stormwater management measures that "will not cause the pre-development runoff rate from a two-year storm to increase when run-off outfalls into a natural stream or will not cause the pre-development peak runoff rate from a ten year storm to increase when runoff outfalls into a man-made channel." Therefore, channel adequacy has been accomplished per the proposed site design. In order to ensure that downstream adequacy exists, Balzer & Associates has provided analysis of the downstream conditions based on compiled data from LPDA, Inc., Albemarle County Geographic Information System, and field data. The downstream conditions were analyzed using the ten-year post-developed run-off rates and average land cover conditions for the area (see attached Hydrology worksheet). The storm sewer system was analyzed for capacity. Based on the data available and the subsequent analysis, it is the professional opinion of Balzer & Associates that the downstream conditions will not be impaired due to the proposed development. Attachments: Drainage Map, 1 of 3 Pipe Run, 2 of 3 Profile, 3 of 3 Hydrology Worksheet Storm Sewer Analysis l � O dO m OO 7. M6:fM a N .q .. * —I 0 4* z -< rn It .. N n "' N .-i N n .. N -4 iJ .-j n 4- .. N :72 N yn '.. N .. 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NM i IIIIIII0 CO MN 00 IN 00.0 mi NI ow O ,,,,4 . ,,,, . w* Iii o r N O N a I m I o I a I m I -n I a I x I - I c- I x I r I C I z I a T N F COLLINS MEDICAL CENTER g o� —1 m j O m m Z Z X m m ; i m: k g m F z 2 -'D f� z p o g c CJ a E l g,T, �Ri '4 y N Z p m A 2 �6 B AAq Z N P y o m m { DRAINAGE MAP ° m < m 3 m $g i 1 � §r D z q = d ° n – B 03 CD 0 RIO DISTRICT F � ss ag o n z m ALBEMARLE COUNTY,VIRGINIA a ° ,Z m I o I 0 m , o I = I - C- I x I r K z 0 J n 0 0 A c:'-8 ' a " c 4e 9.c? 0 pec? i a V - 2a i r`'`pl ,-1pjk Z b "-r-rr-r—clurorr'3 *oil I] rri�a r � p ti «clO� O I�� II-i'a'Z ® / 0 A r �J, k,A 'I'll 1� IV U ti-,'''''' \ ' s I: y C n J J�m/ lil. S -A 0 O Y Om Aky N ti= \ \, s (.7'4 \ i / / Fill ` - '^I In • O m 44447 , n rr:r \\ 0 ti V■ ---- ' - J J i i J n I a l m I o I 0 I m I 'I I 0 I z I — I T x < <' r s I z I o N T N > m F COLLINS MEDICAL CENTER > < 2 i n Z � Z ° o o � ,°o � . n a l3dA=z €Eo�g SAS z '1'1 O N O 0:1 o A - -. 3 H 9 F ps-gy p i B o° _ w d cl - 9 v N PIPE RUN `> Pte= 4� a 1 _ ° RIO DISTRICT N ° w a % F g f' 8 A " - _ z m W ALBEMARLE COUNTY,VIRGINIA f �`�� > I a1 I 0 f 9 I m 1 w I a 1 x l — I .- I x I r I c I Z I 0 o i 6 i A C . III▪ X ..b y (/ ) O � Cj .cA 0 0 STR—A ° �o - + 0 STA O+QO 0 INV OUT =436.40 7\/.\/ \ / o O e., STR—B STA 0+87.73 — Ae,me k, _�. .. , , TOP �—44.42 I o INV IN =430.02 - LJ \© 0 X INV OUT =430.00 _ 01c 0 c z o o ' I I I o — STR—D cO , STA 1 +62.73 TOP =426.60 _ . * -��.�© INV IN =419.50 I I I iv Ow o INV OUT =419.30 0 ° STR—F STA 2+12.72 STR—H - TOP —'12'x.51 TA 2+24.72 -p INV IN =415.65 OP =423.81 3,"? INV OUT s=415.27 INV IN =412 92 ; —‹ 0 B I I . K e - . e i . . 9 F . _ 9 > I w I a 1 9 I ,, I o I a l x I - 1 ,_ I x I r „ me i GJ COLLINS MEDICAL CENTER L , El '�A y § O Z g 8 N O d c A q o --h C D ° m PROFILE N 3 D g .5 _ s$ A= = d - 9 t) N m D o m E ;*O R z n 8 !a -Z a 3 N < PP m O o k ki ki RIO DISTRICT N 0 a € g P=m n i a s I a FI z ALBEMARLE COUNTY,VIRGINIA N 7 HYDROLOGY WORKSHEET 'tire Name ' PROJECT NAME: COLLINS MEDICAL PROJECT#: S0900017 DATE: July 27,2009 BY: WKM ST# DATA CALCULATIONS DA-1 Area= 0.31 ac C Value Time of Concentration POST CA= 0.20 0.19 ac= 61.29 %@ 0.90 C= 0.55 ft OLF@ %= min Tc= 5.00 0.12 ac= 38.71 %@ 0.25 C= 0.10 ft CF @ %= min 12= 5.18 in/hr Q2= 1.04 cfs ac= %@ C= ft CF @ %= min 110= 6.67 in/hr Q10= 1.34 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 1.65 cfs ac= %@ C= User defined 1100= 8.76 in/hr Q 100= 2.20 cfs ADJ. C= 0.648 C factor for OLF= DA-2 Area= 0.09 ac C'Value Time of Concentration POST CA= 0.08 0.09 ac= 100 %@ 0.90 C= 0.90 ft OLF@ -%= min Tc= 5.00 ac= %@ C= ft CF @ %= min 12= 5.18 in/hr Q2= 0.42 cfs ac= %@ C= ft CF @ -%= min -110= 6.67 in/hr Q10= 0.54 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 0.67 cfs ac= %@ C= User defined 1100= 8.76 in/hr Q100= 0.89 cfs ADJ. C= 0.900 C factor for OLF= OFFSITE Area= 0.83 ac C Value Time of Concentration (DITCH-B) CA= 0.65 0.15 ac= 18.07 %@ 025 C= 0.05 ft OLF@ %= min Tc= 5.00 0.68 ac= 81.93 %@ 0.90 C= 0.74 ft CF @ %= min 12= 5.18 in/hr Q2= 3.36 cfs ac= %@ C= ft CF @ %= min 110= 6.67 in/hr Q10= 4.33 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 5.34 cfs ac= %@-C= User defined 1100= 8.76 in/hr Q100= 7.11 cfs ADJ. C= 0.783 C factor for OLF= OFFSITE Area= 0.24 ac C'Value Time of Concentration (SHEET) CA= 0.18 0.t8 ac= 75 %@ 0.90 C= 0.68 ft OLF@ -%= min Tc= 5.00 0.08 ac= 33.33 %@ 0.25 C= 0.08 ft CF @ %= min I2= 5.18 in/hr Q2= 0.94 cfs ac= %@_C= ft CF @ -%= min -110= 6.67 in/hr Q10= 1.21 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 1.50 cfs ac= %@ C= User defined 1100= 8.76 in/hr Q100= 1.99 cfs ADJ. C= 0.758 C factor for OLF= STR-F Area= 9.01 ac C Value Time of Concentration CA= 7.08 7.43 ac= 82.46 %@ 0.90 C= 0.74 ft OLF@ %= min Tc= 5.00 1.58 ac= 17.54 %@ 0.25 C= 0.04 ft CF @ %= min 12= 5.18 in/hr Q2= 36.68 cfs ac= %@_-C= ft CF @ %= min 110= 6.67 in/hr Q10= 47.21 cfs ac= %@ C= Tc= 5.00 min I25= 7.48 in/hr Q25= 58.23 cfs ac= %@ C= User defined 1100= 8.76 in/hr Q100= 77.57 cfs ADJ. C'= 0.786 C factor for OLF= STR-A Area= 1.47 ac C'Value Time of Concentration CA= 1.11 0.24 ac= 16.33 %@ 0.76 C= 0.12 ft OLF@ %= min Tc= 5.00 0.83 ac= 56.46 %@ 0.78 C= 0.44 ft CF @ %= min 12= 5.18 in/hr Q2= 5.77 cfs 0.31 ac= 21.09 %@ 0.65 C= 0.14 ft CF @ %= min 110= 6.67 in/hr Q10= 7.42 cfs 0.09 ac= 6.122 %@ 0.90 C= 0.06 Tc= 5.00 min 125= 7.48 in/hr Q25= 9.16 cfs ac= %@ C= User defined I100= 8.76 in/hr Q100= 12.20 cfs ADJ. C'= 0.758 C factor for OLF= 1 „ , i ,apt✓' ', T T .. y 2 m O W D �O S z 9111 liii '��• m I71 O � =D zz 2 T A D r r A nc N O T r ::::z z • o_ IILHO (l J OD ! ,,, ,,, :rt' • i • ' � < o op '�.. 0 0 0 to m z 0 cn oo....o m3 O m' I � •� V cW0 T D < cD N . q n N W W # G m A H v0 11411 l 2 m o co D g CO (n M V W m m (0 M to M Cr; MI M N (N N V 7 7 - V K N 0 V W N V N v N I � r ai � (n'N O. (o v (O Lo CO O M M 'Si N N C C V V STORMWATER MANAGEMENT REPORT Collins Medical Center bATILD AND ASSOCIATES INC py REFLECTING TOMORROW 1561 Commerce Road, Suite 401 Verona, VA 24482 540-248-3220 Prepared by: Balzer & Associates Project No: S0900017 September 14,2009 Resubmitted December 13, 2013 Noe Adequate Channel As described herein, a closed storm sewer system collects the majority of the stormwater run-off from the project site. It is our assumption that this pipe is associated with a regional stormwater pipe system. In accordance with the Virginia Erosion & Sediment Control Regulations, VR 625-02-00, § 1.5 Minimum Standards, Section 19.c(3), the proposed site design provides stormwater management measures that "will not cause the pre-development runoff rate from a two-year storm to increase when run-off outfalls into a natural stream or will not cause the pre-development peak runoff rate from a ten year storm to increase when runoff outfalls into a man-made channel." Therefore, channel adequacy has been accomplished per the proposed site design. Attachments: Drainage Map, Sheet DA-1, DA-2 Performance-Based Water Quality Calculations (1 pages) Hydrology Worksheet (1 pages) Pipe Calculations (1 page) Channel Calculations (8 pages) Filterra Technical Bulletin(9 pages) Filterra Letter(1 page) Pondpack Calculation (12 pages) > 1 m 1 r) ] o I m I m I 0 _ r J s f I I x I 1 c I z [: G L A \ \ I�� 1 O x \ � N?W \ N \ C.) \ N 'r m{ Am \ \ \ \ \ \ \ \ \ \ --'•.,,,,,,, \ \ \ \ \ \ \ \ \ _ C.0 \ / cmm 1 P, u L Gb / l A > �� alma ,'Zt 611 W„ I O,6f°i�5N - ,\ fZ I B'SAN - B'SAN B•SAN ���_ -_--- - I B'SAN --- - d.p I S`N 8'SAN 8'SAN— mln I I -- d I \ o I. s \\ I — — — — — — — — — — 1 y7/ \ / I eill o it/ D - I 1 I I ' / 1 I / H.U' II. // 1 I I _=J� 0 1 p I / 1 1 1 co co/ n 1 _ - 445- ------ _ �r - II 1 IL — — -■ 1111111111111IN - - - - - 1 1 II r.. . .. . _ . .. �- r. ------- __---450- / „ II — — ,o 11 II O I 1 , ' I I — — — — li o IIO ti /4 , ■ II - - - - - /-{ � � o_Ti — — i %4 i _ _ _ _v == f n / H, I — lJ II — — \ CO 11 > �I° ILr - - - - H , � _ z w \I I , • i - I 1 a N — — — — — --II I II I /- - - CD `. CA / — — I�1♦ Q o II N..)1 n /' r y�' — — s II of r i - - - - -11 II — — 1 -)1 II 1 0 I /r--—J� I I m 1\ I r II o __41111 +—' P—P dH0--d1-10- -- ANC 8,40 dH0 dH0 dH0— dH0—dH0 ° 9dN0 7��9 dA0 72- u 1 ❑ dHO--_dH0 dNC 554 3 � - - - — — ----a a its aim am.-IMMI y I a v ° v o o ° ° ao 0 .° o a o o a v / / / ° WESIF, 'L1D ROAD 8 STATP ROUTE 1452 . _65' R-0-14/) — — 0 NtlS.B NVS.8 NVS.8 Ntl S,B NVS.8 NNS.e 888.13 / Ntl S.e NVS.8 NtlS. o N // 25 MPH 0 1 1 1 — 1 SIDEWALK ro > I m 1 0 1 0 1 m I m 1 0 1 x I - I , I x I r I c I z I, o ° _ r1 ' = _ COLLINS MEDICAL CENTER W �" , o o "' `x f A i an d iP0; ¢l€s A n n DN Z m AO W O N € R 6 A F S s Z +'N z o m 'a F u' ° EXISTING DRAINAGE MAP 3 o-F fl; H< m > a g 'o S H ; n tel°o o 8 x RIO DISTRICT ° ' 2 i' € c^ F A Z K CO m ALBEMARLE COUNTY,VIRGINIA ° 0 1� > I CO I n I o 1 m I m 1 G) I x f - I I x I r I s z I c. r I I KN VUrm 1 � � nl Sxx III _ \ � \ z nzm I `2-am ■ w / - - ■ - w / ■ / I / I U O • 8SAN 8SAN 8SAN Al"..... _ 1 8'SAN _ — 1\ _ L A _—_— O N 8'SAN =B-SAN-- —, — ab I O I \ qCn I I _ r ON _�_ - 11: I_ \\ I q / III. 1 II D 1 II I II II II I I --ofl- I < �' II //' ' Alt o I I - Ip ' // / 1 _ —.— — ■ / • • • Q / 1 I 1IIo ----450-1 \�- _ = I 11 I ( lii - ' 0 1 it 11 , I liii}tell■� "�a f ,,n - - - - �I�II Ial�` "- , II — — — —may II■_: ; i - n II 11 n O is I ■I■I I II O II I / o II■ �y 11 I I. 1 :. / - - / 00 1 u � l / Crl n ,, — • / I II/1■ 0 /"N ' 1 tiI II ■ n // r — - - — HII' of II■■■ ' i — II 11 1 7 0 II , _ /„., _ _j_, ,77 I � m, r., , L. A lr , a ,., !cls,, t\ 1 ` - a — — __ 1� `r V _ _ _ _\ ��—..__p_dH0 dH0 /.HN —dH0 .HN dHO dH0 © . dHS�4 -— I H�119 /2' __.• f _ ❑ dHN--dH0 dHp G G V v 4 v �� vU v a v d /\RS TRI/gL D ROA D STAT,P ROUTE 1452 \ 6 P-O-_W)- NtlSe NtlSB _ NVSB NVSB — — — — — — NtlSB NtlS,8 NVS.8 / NV S8 NV S8 NVS r . i 25 MPH / _ SIDEWALK IV > 1 m I n 1 o I m I -n I 0 I x I - I I x 1 r I s I z I o o T > o o I COLLINS MEDICAL CENTER a • .C� m �, N n D m m i 'i • `^ � r^ 2 � X m 3 �f LL O Y z O O O m of g 4] n a EFZ S o3£g i, A i Z •'4N1 0 1 , ° K m 1 PROPOSED DRAINAGE MAP N m < r 3 N g P gs t i d A 3 i a n o °o = Jo RIO DISTRICT o N 'g T €g i i ` p, ° in O K m nA c6a F •�1n Z ALBEMARLE COUNTY,VIRGINIA p, 1 WAR QUALITY CALCULATION WOFHEET Developed in accordance with Virginia Stormwoter Management Handbook. Enter data in highlighted cells. Others contain formula. PROJECT NAME: COLLINS MEDICAL PROJECT it S0900017 DATE: June 29, 2009 BY: WKM PRE-DEVELOPED PHOSPHOROUS LOADING: 0.55 =Area of Site (acres) 0.442 = Pre-Dev Phos. Load Factor(!b/ac/yr)from Table 1 0.243 =Pre-Dev Phos. Loading(Ib/yr) PRE ON-SITE POST-DEVELOPED PHOSPHOROUS LOADING: SubArea Area (ac) %Imperv. Fpost Lpost 1 0.55 56% 1.26 0.69 0.00 TOTAL= 0.69 lb/yr POST PHOSPHOROUS REMOVAL REQUIREMENT(RR): 0.69 = Past-Dev. Load (lb/yr) 0.243 = Pre-Dev. Load (Ib/yr) 0.45 =Removal Rate(Ib/yr) RR PHOSPHOROUS LOADING FOR ON-SITE AREAS: SubArea Area (ac) %Imperv. Fpost Lpost 1 0.31 58% 1.30 0.40 2 0.1 100% 2.17 0.22 0.00 0.00 TOTAL= 0.62 lb/yr ON-SITE E PHOSPHOROUS LOADING FOR OFF-SITE AREAS: SubArea Area (ac) %Imperv. Fpost Lpost 0.00 TOTAL= 0.00 lb/yr SELECT BMP: OFF-SITE SubArea Area (ac) Lpost %Imprv. BMP Eff(%) Lrp(Ib/yr) Design Vr(cu.ft.) 1 0.31 0.40 58% 74% 0.30 FILTERA 322 2 0.1 0.22 100% 74% 0.16 FILTERA 172 0 0 0.00 0% 0.00 0 0 0 0.00 0% 0.00 0 0 0 0.00 0% 0.00 0 TOTAL= 0.46 total= 494 EVALUATION = PASS total(acre ft)= 0.01 Page 1 of 1 1 HYDROLOGY WORKSHEET PROJECT NAME: COLLINS MEDICAL PROJECT#: S0900017 DATE: July 27,2009 BY: WKM ST# DATA CALCULATIONS DA-1 Area= 0.31 ac C'Value Time of Concentration POST CA= 0.20 0.19 ac= 61.29 %@ 0.90 C= 0.55 ft OLF@ %= min Tc= 5.00 0.12 ac= 38 71 Fa@ 0:25 C= 0.10 ft CF @ = min 12= 5.18 in/hr Q2= 1 04 cfs ac= %@ C= ft CF @ %= mm I10= 6.67 in/hr Q10= 1 34 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 1.65 cfs ac= %@ C= User defined -I100= 8.76 in/hr Q100= 2.20 cfs ADJ. C'= 0.648 C factor for OLF= DA-2 Area= 0.09 ac C'Value Time of Concentration POST CA= 0.08 0.09 ac= 100 %@ 0.90 C= 0.90 ft OLF@ , = min Tc 5.00 ac= %@ C= ft CF @ %= min I2= 5.J8 in/hr Q2= 0.42 cfs ac= %@ C= . ft CF @ %= min 110= 6.67 in/hr Q10= 0.54 cfs ac= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 0.67 cfs ac= %@ C= User defined 1100= 8.76 in/hr Q100= 0.89 cfs ADJ. C'= 0.900 C factor for OLF' UNDETAINED Area= 0.15 ac C'Value Time of Concentration POST CA= 0.06 0.03 ac= 20 %@ 0:90 C= 0.18 - ft OLF@ - = min Tc= 5.00 - 0.12 ac= 80 %@ 035 C= 0.20 ft CF @ - = min I2= 5.18 hr Q2= 0.30 cfs ac= %@ C= ft CF %= min 110= 6.67 in/hr Q10= 0.38 c f s • a c= %@ C= Tc= 5.00 min 125= 7.48 in/hr Q25= 0.47 cfs - ac= %@-7c= User defined 1100= 8.76 in/hr Q100= 0.62 cfs ADJ. C'= 0.380 C factor for OLF= DA-1 Area= 0.31 at C'Value Time of Concentration PRE -CA= 0.08 0.31 ac= 100 %@ 0.25 C= 0.25 - • ft OLF@- = min -Tc= 5.00 - ac= %@ C= • ft CF @ %= min I2= 5.18 in/hr Q2= 0.40 cfs ac= %@ C= ft CF @ %= min 110= 6.67 in/hr Q10= 0.52 cfs ac= %@ C= Ti" 5.00 min I25= 7.48 in/hr Q25= 0.64 cfs ac= %@ C= User defined I100= 8.76 in/hr Q100= 0.85 cfs ADJ. C'= 0.250 C factor for OLF= DA-2 'Area= 0.09 ac C'Value Time of Concentration PRE CA= 0.02 - .0.09 ac= 100 %@ •0.25 C= 0.25 ' . ft OLF@ %= min Ti" 5.00 ac= %@ C= -ft CF@ -%= min - -12= 5.18 in/hr Q2= 0.I2 cfs • '. ' ac= %@ C= ft CF @ .o= min 110= 6.67 in/hr Q10= 0.15 ifs - ac= %@ C= Tc= 5.00 min • I25= 7.48 in/hr Q25= 019 cfs - ac= %@ C= User defined 1100= 8.76 in/hr QI00= 0.25 cfs ADJ. C'= 0.250 C factor for OLE= • NDETAFNED Area= 0.15 ac C'Value . Time of Concentration PRE CA= 0.04 0.15 ac= 100 %@ 0.25 C= 0.25 . ft OLF@- = min 'Tc= 5.00 - ac= %@ 77 C= . . ft CF@ -- = min 12= 5.18 in/hr Q2= 019 cfs . ac= %@ C= _ •ft CF C %= min I10= 6.67 in/hr Q10= 025 cfs -ac= %@ C= Tc= 5.00 min I25= 7.48 in/hr Q25= 0.31 cfs ac= %@ C= User defined 1100= I 8.76 in/hr Q100= 0.41 cfs ADJ. C'= 0.250 C factor for OLF= OFFSITE i Area= 0.83 ac C'Value Time of Concentration (DITCH-13) CA= 0.65 0.15 ac= 18.07 %@ 0.25 C= 0.05 - ft OLF@ %= min 'Tc= 5.00 0.68 ac= 81.93 %@ .0.90 C= 0.74 - ft CF @ %= min 12= 5.18 in/hr = 3.36 cfs ac= %@ C= ft CF @ -%= min . r Q110= 6.67 in/hr Q10= 4.33 cfs ac= %@ C= Tc= 5.00 rain 125= 7.48 in/hr Q25= 5.34 cfs ac= %@ • C= User defined 1100= 8.76 in/hr QI00= 7.11 cfs ADJ. C'= 0.783 C factor for OLF= PONDPACK 'Area= ' ac C'Value Time of Concentration •REQD -CA= at= ######%@ C= 14DIV/01 ft OLF@ %= min Tc= 5.00 ac= 6#####%@ C= #DIV/0! ft CF @ = min 12= 5.18 in/hr Q2= 0.12 ifs ac= ######%o@ C= #DIV/0! ft CF @ -,o= min 110= 6.67 in/hr Q10= 0.16 cfs ac= #,3444444%@ C= #DIV/0! Tc= 5.00 min 125= 7.48 in/hr Q25= 0.19 cfs ac= ######%@ C= #DIV/0! User defined 1100= 8.76 in/hr Q100= 0.26 cfs ADJ. C'= C factor for OLF= - DITCH A Area= ac C'Value Time of Concentration CA= ac= €#####%@ C= #DIV/0! ft OLF@ %= min Tc= 5.00 ac= ######%@ C= #DIV/0! ft CF @ %= min 12= 5.18 in/hr Q2= 1.20 cfs ac= r#####%@ C= #DIV/0! ft CF 5 .o= min 110= 6.67 in/hr Q10= 5.40 cfs ac= #t#t###%@ C= #DIV/0! Tc= 5.00 min 125= 7.48 in/tu Q25= cfs ac= ######%@ C= #DIV/0! User defined 1100= 8.76 in/hr Q100= cfs ADJ. C'= C factor for OLF= DITCH C Area= ac C'Value Time of Concentration CA= ac= ######%IE C= #DIV/0! ft OLF@ = min Ti- 5.00 ac= ##6##-#%5 C= #DIV/0! ft CF 5 = min 12= 5.18 in/hr Q2= 0.83 cfs ac= ######'%@ C= #DIV/0! ft CF @ - o= min . -110= 6.67 in/hr Q10= 1.07 ifs ac= #96566165 C= #DW/0! Tc= 5.00 min 125= 7.48 in/hr Q25= cfs at = #68 1486%@ C= #DIV/0! User defined 1100= 8.76 in/hr Q100= cfs ADJ. C'= C factor for OLF= 0, co m CO CO t CD CI LO LI) o • O M m 6 N F t6 7 V V V v v v v v 1 to 6 6 O a `"- 1- N N n 0 �.M O N N sr 1- V V 7 NI' sr V . In V N C 71 Q t6 O t6 O O I l O to M CO t6 0 O O O O sr R' - V V V W'I)Q O O O N el Ui W Ia 0''O O O O aI,U I W'3 � Ii-7t1 I ••L • ID 1� O O ' 1,,,1..2 iO O OO O a. IVIN ;N':m' Imo,N O M,0 V O CO 1 >Ia ° o':,_ to l i co 6 co 6 co to dV �j�, t6 6 ID el Iy : ! 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Lj I o,o' m ),fA W cT ttY, 1Q i0'O'j°j : 1 O O'0 U O O D 0'O . a 1 l Z O O O O O 10 0 0 0,0 a i N O 1• O O 1 0 0 0,0 0 I<C I th O O O e0 I ,U 4 ',O O 0.0'0 9 t- Fi i0Z jN',g' �' 3 i �E ~a o1 �11�I o . � l l '' .11. oZ Iii Ni all I I I 1 1 i l l I I Worksheet Worksheet for Triangular Channel • Project Description Worksheet DITCH-A 10YR Flow Element Triangular Char Method Manning's Forrr Solve For Channel Depth Input Data Mannings Coeffic 0.030 Channel Slope 070000 fUft Left Side Slope 4.00 H :V Right Side Slope 4.00 H:V Discharge 5.40 cfs Results Depth 0.51 ft Wiz +— Qr-t? \4 Flow Area 1.0 ft2 Wetted Perimi 4.21 ft Top Width 4.09 ft Critical Depth 0.65 ft Critical Slope 0.019905 ft/ft Velocity 5.17 ft/s Velocity Head 0.42 ft Specific Enerc 0.93 ft Froude Numb 1.80 Flow Type supercritical Project Engineer balzer j.\...\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.00051 07/22/09 0d:47:38 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Worksheet for Triangular Channel Project Description Worksheet DITCH-B 2YR Flow Element Triangular Char Method Manning's Forrr Solve For Channel Depth Input Data Mannings Coeffic 0.030 Channel Slope 250000 ft/ft Left Side Slope 6.00 H:V Right Side Slope 6.00 H:V Discharge 3.36 cfs Results Depth 0.29 ft Flow Area 0.5 ft' Wetted Perimf 3.51 ft Top Width 3.46 ft Critical Depth 0.45 ft Critical Slope 0.021875 ft/ft Velocity 6.74 ft/s Velocity Head 0.71 ft Specific Enerc 1.00 ft Froude Numb. 3.13 - Flow Type supercritical Project Engineer:balzer j:\...\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.0005] 07/22/09 04:47:27 PM ©Haestad Methods. Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 rrr N fir Worksheet Worksheet for Triangular Channel Project Description Worksheet DITCH-B 10YR Flow Element Triangular Char Method Manning's Forrr Solve For Channel Depth Input Data Mannings Coeffic 0.030 Channel Slope 250000 ft/ft Left Side Slope 6.00 H:V Right Side Slope 6.00 H:V Discharge 4.33 cfs Results i Depth 0.32 ft - Flow Area 0.6 ft2 Wetted Perim' 3.86 ft Top Width 3.81 ft Critical Depth 0.50 ft Critical Slope 0.021119 ft/ft Velocity 7.18 ft/s Velocity Head 0.80 ft Specific Enerc 1.12 ft Froude Numb. 3.18 Flow Type supercritical Project Engineer:balzer j:\...\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.00051 07/22/09 04:47:16 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Worksheet for Triangular Channel Project Description Worksheet DITCH-C 10YR Flow Element Triangular Char Method Manning's Forrr Solve For Channel Depth Input Data Mannings Coeffic 0.040 Channel Slope 030000 ft/ft Left Side Slope 3.00 H :V Right Side Slope 3.00 H :V Discharge 1.07 cfs Results Depth 0.41 ft ' l D�Ac- t7q-pr-tk = 1, ej r Flow Area 0.5 ft2 Wetted Perim 2.58 ft Top Width 2.44 ft Critical Depth 0.38 ft Critical Slope 0.043515 ft/ft Velocity 2.15 ft/s Velocity Head 0.07 ft Specific Enerc 0.48 ft Froude Numb, 0.84 Flow Type Subcritical Project Engineer.balzer j:\...\civil\calculations\stormwater\hydro_fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.0005] 07/27/09 07:18:03 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Worksheet for Trapezoidal Channel Project Description Worksheet FILTERRA-1 C.F L) Flow Element Trapezoidal Cha Method Manning's Form Solve For Channel Depth Input Data Mannings Coeffic 0.013 Channel Slope 010000 ft/ft Left Side Slope 0.01 H :V Right Side Slope 0.01 H :V • Bottom Wdth 3.00 ft Discharge 1.38 cfs Results Depth 0.15 ft Flow Area 0.5 ft2 Wetted Perim' 3.30 ft Top Width 3.00 ft Critical Depth 0.19 ft Critical Slope 0.005015 fUft Velocity 3.04 fUs Velocity Head 0.14 ft Specific Enerc 0.30 ft Froude Numb, 1.38 Flow Type iupercriticai Project Engineer: balzer j:\._\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.00051 07/15/09 10:28:09 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Worksheet for Triangular Channel Project Description Worksheet SWALE- 1 C-Oc F Sc t-CA 1> = 5‘JAti– Flow Element Triangular Char Method Manning's Forrr Solve For Channel Depth Input Data Mannings Coeffic 0.030 Channel Slope 020000 ft/ft Left Side Slope 2.00 H:V Right Side Slope 2.00 H:V Discharge 0.54 cfs Results Depth 0.36 ft Flow Area 0.3 ft2 Wetted Perimt 1.61 ft Top Width 1.44 ft Critical Depth 0.34 ft Critical Slope 0.027547 ft/ft Velocity 2.08 ft/s Velocity Head 0.07 ft Specific Enerc 0.43 ft Froude Numb. 0.86 Flow Type Subcritical Project Engineer:balzer j:\...\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.0005] 07/15/09 10:25:47 AM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Worksheet for Circular Channel Project Description Worksheet EXIST. PIPE 2 Flow Element Circular Chann Method Manning's Fon Solve For Channel Depth Input Data Mannings Coeffic 0.013 Channel Slope 010000 ft/ft Diameter 15.0 in Discharge 4.20 cfs Results Depth 0.73 ft Flow Area 0.7 ft' Wetted Perime 2.18 ft Top Width 0.00 ft Critical Depth 0.83 ft Percent Full 58.7 % Critical Slope 0.006963 ft/ft Velocity 5.60 ft/s Velocity Head 0.49 ft Specific Energ: 1.22 ft Froude Numbe 1.27 Maximum Disc 6.95 cfs Discharge Full 6.46 cfs Slope Full 0.004228 ft/ft Flow Type supercritical Project Engineer: balzer j:\__\civil\calculations\stormwater\hydro_fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.00051 07/23/09 0435:29 PM ©Haestad Methods,Inc. 37 Brookside Road Waterbury,CT 06708 USA +1-203-755-1666 Page 1 of 1 Worksheet Name Worksheet for Circular Channel Project Description Worksheet EXIST. PIPE 1 Flow Element Circular Charm Method Manning's Forr Solve For Channel Deptl Input Data Mannings Coeffic 0.013 Channel Slope 010000 ft/ft Diameter 15.0 in Discharge 5.40 cfs Results Depth 0.87 ft Flow Area 0.9 ft' Wetted Perime 2.48 ft Top Width 0.00 ft Critical Depth 0.94 ft Percent Full 69.9 % Critical Slope 0.008312 ft/ft Velocity 5.89 ft/s Velocity Head 0.54 ft Specific Energ: 1.41 ft Froude Numbe 1.16 Maximum Disc 6.95 cfs Discharge Full 6.46 cfs Slope Full 0.006989 ft/ft Flow Type supercritical Project Engineer: balzer j:\._.\civil\calculations\stormwater\hydro.fm2 Balzer and Associates,Inc. FlowMaster v7.0[7.00051 07/23/09 04:35:41 PM ©Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 USA +1-203-755-1666 Page 1 of 1 Technical Bulletin 6 Minimum Standard 3.11C Minimum Standard 3.11C Filterra'M Bioretention Filter System (revised 11/01/02) Definition The FilterraTM treatment system is a manufactured bioretention stormwater best management practice (BMP) that filters stormwater runoff from impervious surfaces (roadways, parking lots and roof tops). The FilterraTM treatment system consists of a concrete container filled with an engineered soil filter media, a mulch layer, an under-drain system and a tree, shrub or other plant selection. This filtration system can be integrated into the site design of both new development and redeveloped projects. Runoff drains directly from the impervious surface, through the filter media, and then out of the container through the under drain system to be discharged to a receiving system or infiltrated into the surrounding soil. Purpose FilterraT""is designed to be a water quality filter device to remove a wide range of nonpoint source pollutants from urban runoff in the same manner as bioretention practices (refer to Minimum Standard 3.11: Bioretenion Practices). Pollutants are efficiently removed by a complex combination of physical, chemical and biological processes within the mulch, soil particles, microorganisms, and the plant materials. FilterraT"'can serve as a water quality BMP in areas where discharge of stormwater runoff into the sub-soils is not desired (e.g., gas stations and karst soils). An under drain system is used to convey filtered runoff to an adjacent drainage system. Where soils are permeable and ground water recharge is desirable FilterraTM can be designed to infiltrate highly treated water into the subsurface. It can be used as a filter only or as a combination filter and infiltration device. FilterraTM is generally not used for attenuation of large volumes of runoff for stream channel erosion control and flood control purposes. However, some degree of volume/flow reduction can be achieved by combining this filter system with an adjacent under ground storage / detention system (gravel trench or pipes). Such a combined system may be useful for urban retrofit projects to address problems associated with combined sewer overflows or for stream protection. TB6-I Nape Technical Bulletin 6 Minimum Standard 3.11C 'Conditions where Practice Applies' FilterraTM takes up little space (surface area or depth) and can be used in any type of urban or suburban commercial, industrial or residential development. FilterraTM is a suitable device for urban retrofit due to its flexible design, sizing criteria and concrete container and easy drop in place construction, it can be installed within the green space or streetscapes of redevelopment projects. FilterraTM can be modified to fit any curb line as a drop inlet along roadways, parking lots, or pedestrian plaza areas, See Figure 1. An adjacent drainage conveyance system is necessary in order to connect the under-drain system, and accept large storm bypass flows. X LL r :7 4 ,zFib • 4 ; '- 1 1s , 1� Y .ry�HYt Figure 1.1. FilterraTM Urban Streetscape Design It is designed to be used where runoff is likely to contain high concentrations of urban pollutants such as heavy metals, oil, and organics (such as gas stations, maintenance facilities and roadways). The system can be used alone or in combination with other BMP's. When used alone, pretreatment is not necessary as the system is designed to operate effectively without clogging from typical urban runoff concentrations of sediment and other particulate matter. The nature of the surface mulch and engineered filter media is such that particles become entrained into the mulch /filter media itself without clogging at the surface. The plant root system also keeps the soil open and free from clogging. As long as the TB6-2 fire Technical Bulletin 6 Minimum Standard 3.11C manufacturer's operating and maintenance procedures are followed the filter device is projected to work for 20 years or more without replacement of the filter media or plant material. Plannin • Considerations Site Conditions The enclosed non-permeable concrete container makes FilterraT'^suitable for situations where infiltration is undesirable or not possible. These situations would include: karst topography, high groundwater conditions, close proximity to buildings, steep slopes, contaminated soils, brownfields sites, highly contaminated runoff or where chemical or oil spills are likely (maintenance facilities, industrial and gas stations). For"hot spots"where chemical spills are likely, the system can be fitted with a valve to quickly close the discharge drain pipe isolating the spill in the concrete container and filter media for easy clean- up, removal and replacement. Where FilterraTm is being used to provide a combination of filtration and infiltration into the adjacent soils, planning considerations should include unique site conditions such as soil permeability, seasonal high groundwater table, depth to bedrock, karst topography, etc. Soil permeability will determine the degree to which it can be used as an infiltration device. For further discussion on planning considerations for infiltration practices, refer to the planning considerations described in the General Infiltration Practices, Minimum Standard3.10, and Bioretention Basin Practices, Minimum Standard 3.11. Developed Conditions FilterraT''is highly adaptable and can be used for most developments. Since the filter is contained in a concrete box it can be built in and around roadways sidewalks buildings and parking lots. It can be installed on many slope conditions typical of parking lots and roadways. In highly urban areas it is possible to use it in the design of an entire streetscape converting the typical non-functional streetscape into one large vegetated filter treatment device. Location Guidelines FilterraTm is best incorporated into the overall site, or streetscape or parking lot landscaping plan. The individual box locations represent a combination of drainage considerations (based on final grades and water quality requirements), desired aesthetics, and minimum landscaping requirements, and must be coordinated with the design of the drainage infrastructure. TB6-3 New Technical Bulletin 6 Minimum Standard 3.11C Aesthetic Considerations Aesthetic considerations must be evaluated early in the site planning process. While topography and hydraulic considerations may dictate the general placement of each structure, overall aesthetics of the site should be integrated into the site plan and stormwater concept plan from their inception. Both the stormwater engineer and the Landscape Architect must participate during the layout of facilities and infrastructure to be placed on the site. Sediment Control Similar to bioretention basins and sand filters, FilterraT"'if installed prior to full site stabilization and without proper inlet protection will become choked with sediment from upland construction operations, rendering it inoperable from the outset. Simply providing inlet protection or some other filtering mechanism during construction will not adequately control the sediment. One large storm may completely clog the soil media, requiring immediate maintenance. FilterraTM should be installed AFTER the site work is complete and stabilization measures have been implemented. (External and adjacent drainage and conveyance systems are typically built along with the site utilities and other infrastructure, and later connected to the boxes when installed. If this is not possible, strict implementation of E&S protective measures must be installed and maintained in order to protect the filter media from premature clogging and failure. Sizing Guidelines In general, bioretention has proven successful in part because of the relatively small surface area, low construction costs and ease of maintenance. FilterraTM provides these same benefits. The current Minimum Standard 3.11: Bioretention Practices establishes a target ratio of bioretention surface area to contributing impervious area of 2.5%. The manufacturer of FilterraTM in cooperation with the University of Virginia has conducted research to optimize the flow/ pollutant removal characteristics of the filter media to significantly reduce this ratio. The patented filter media has both high flow rates and high pollutant removal capabilities. To establish the sizing criteria the manufacturer has examined the rainfall distribution and frequency data from the mid-Atlantic region to size the filter surface area to treat 90% of the total annual rainfall volume. Pollutant removal data was also related to the filter surface area and drainage area relationships. The optimum filter surface area to drainage area ratio is 0.33%. For example, the required minimum size filter for 1/4 acre of impervious surface would be 36 square feet of filter surface area or one 6 ft. by 6 ft. filter box. TB6-4 Nue Nevi Technical Bulletin 6 Minimum Standard 3.11C The pollutant removal rates for FilterraTM also vary as a function of the filter surface area to drainage area. At the minimum 0.33% ratio filtering 90% of the annual runoff the expected pollutant removal rates are shown below. It is not recommended that a ratio of less than 0.33% be used. Expected Pollutant Removal (@ 0.33%filter surface area/drainage area) Total Suspended Solids Removal = 85% Total Phosphorous Removal = 74% Total Nitrogen Removal = 68% Total Metal Removal = 82% Higher pollutant removal rates are possible by increasing the ratio of filter surface area to drainage area. See the manufactures detailed calculations for sizing and pollutant removal on their web site at: i rttp:liwww.americastusa.comffilterra.htrnl. Local jurisdictions may want to consider achieving the highest pollutant removals possible to protect water supplies (surface and ground water) or sensitive water bodies and streams. This may be achieved with FilterraTM by increasing the filter surface area to drainage area ratio. However it is well documented that the pollutant removal efficiency of a filter device varies with the concentration of pollutants in the inflow (the higher the pollutant levels are in the inflow the higher the pollutant removal rates will be). In order to account for this variability in efficiency, the maximum allowable pollutant removal rates for FilterraTM are as follows: Maximum Pollutant Removal Rates Total Suspended Solids Removal = 90% Total Phosphorous Removal = 80% Total Nitrogen Removal = 65% Total Metals Removal = 85% *The above guidance on calculating pollutant removal is based on review of the manufacturer's laboratory data and the best available existing body of data on bioretention systems. However, these removal rates are subject to continuing review, and evaluation of future monitoring data. These pollutant removal rates may be modified on a periodic basis by DCR as determined by ongoing field testing and future improvements to the FilterraTM system. * TB6-5 gin/ Technical Bulletin 6 Minimum Standard 3.11C Design Criteria General The design of FilterraT"'shall be in accordance with manufacturers specifications. The designer is not only responsible for selecting the appropriate components for the particular design but also for ensuring long-term operation. Soils Investigation When infiltration into the surrounding subsoil is desired, refer to the Planning Considerations and Design Criteria of General Infiltration Practices, MS- 3.10, and to local jurisdiction soil study requirements such as Chapter 5, Section V. of the Northern Virginia BMP Handbook. A minimum of one soil boring log should be required for each structure where infiltration is considered. Sizing Methodology The designer must verify that FilterralM has been sized and installed in accordance with the manufacturer's specifications. The distribution and sizing of the system of filters should be in accordance with the manufacturer's recommendations to achieve the most cost-effective treatment practicable while satisfying the performance-based or technology-based water quality criteria. Typical development /redevelopment streetscape or parking lot design will use a minimum of one 6'x6' filter box in an off-line configuration for every %of drainage area, or a combination of boxes so as to maintain a 0.33% ratio of filter surface area to drainage area. When designing the system, consideration must be given for overflows during major storm events. Once the filter flow capacity is exceeded a backflow condition develops forcing runoff to by-pass the filter. Overflows should be diverted to a safe conveyance device (inlet, swale or green space). Pretreatment Pretreatment is generally not necessary as the filter's media, mulch and plant root system is designed to operate without clogging under normal conditions. Routine annual inspection and maintenance will ensure that the filter will operate for at least 20 years. Normal conditions mean a stabilized drainage area with typical concentrations of sediment and other urban pollutants. Follow the manufacturer's recommendations for unusual site conditions where high pollutant loads are expected. If it is installed when there is active construction within the TB6-6 `err' v Technical Bulletin 6 Minimum Standard 3.11C drainage area the opening to the filter should be blocked off. Follow the manufacturer's recommendations on protection of the filter box and media during construction activities. Observation Well and Clean-out FilterraTM is typically delivered to the site completely assembled or assembled by the manufacturer at the site. The system comes with an observation well installed that can also be used as a clean out to remove any blockages in the under drain piping. Plant Materials The plant materials used for FilterraT""should follow the manufacturer's recommendations. Generally, the manufacturer will provide and install the filter material and plants. The system can use typical readily available landscape plant materials. It is designed to use upland plants not wetland plants. FilterraTM provides a hydrologic regime where wetland plants will not survive and should not be used. The plants used for bioretention will also work for FilterraT"'. See Minimum Standard 3.11a Bioretention Basin Practices. One of the advantages of this system is that it uses commonly available nursery stock plant materials so the end user can select from a wide range of plants to also achieve aesthetic and habitat values.The types of plants used will also determine the depth and design of the concrete container. The standard 6'x 6' box is designed to accommodate a typical shrub, herbaceous material or a very small tree. If a standard street tree is used, the filter box must be larger to accommodate the larger root system, prevent wind throw and to ensure adequate filter surface area as the tree matures. A 9'x 12' box would be the minimum size needed for most street trees. In some cases the manufacturer may recommend a customized box size and configuration to accommodate special plant requirements, unique site conditions, water quality protection goals and ensure adequate performance. It is not recommended that one filter be used to treat very large volumes of runoff from a large drainage area. Runoff should not be detained and stored in a holding tank to be metered out to the filter media over a long period of time. Exposing the soil, microbes and plants to prolonged and frequent flooding and wet conditions will significantly change the hydrologic regime reducing the effectiveness of the media to capture pollutants and the microbe's/plant's ability to cycle nutrients, break down organics and uptake heavy metals. Therefore, continuous or frequent flows (such as basement sump pump discharges, cooling water, condensate water, artesian wells, etc.) MUST BE EXCLUDED from routing through the system. If the filter media remains water logged for 3 or 4 days anaerobic conditions will develop dropping both oxygen and pH levels which may kill desirable soil microbes and the plants. FilterraTM is an upland system that must periodically dry out to maintain aerobic conditions to ensure the TB6-7 Nvie vase Technical Bulletin 6 Minimum Standard 3.11C productivity and vigor of the microbes and plants. The unique filtering system approach of designing for small drainage areas and distributing the filters uniformly throughout the site ensures that the filter drains properly in about one hour to maintain aerobic conditions and enable the filter to be ready to accept the next rain storm event in just a few hours. Follow the manufacturer's recommendations on sizing and distribution of the filter boxes as deviations from the manufacturer's specifications may void any manufacturer's warranty and significantly reduce the ability of the filter to perform properly. Construction Specifications Accepted construction standards and specifications should be followed where applicable. Specifications and the work should conform to methods and procedures applicable to the installation of a prefabricated concrete box such as an inlet or other type container structure. The construction specification of the concrete container or use of an alternative material for the container should comply with the recommendations of the manufacturer and all applicable standards by the local or state approval authority. Sequence of Construction FilterraT"' can be constructed and installed at any convenient time during the construction of the site or after the installation of the site's infrastructure as a "drop in place" devise. However, it should not be placed in service until the contributing drainage area has been stabilized. If the device is installed during the construction of the site's infrastructure, the inlet opening must be protected from sediment. Follow the manufacturer's recommendations on sediment/ erosion protection. The specification for the construction of the system should state the following: 1) the earliest point at which the runoff can be safely directed to the device and 2) the means by which this "delay in usage" is to be accomplished. When the device is made operational will depend on a variety of unique site conditions and should be evaluated and determined on those conditions. Excavation When FilterraTM is to be used in conjunction with or as an infiltration device the preparation of the infiltration trench placement and type of stone used or filter fabric should conform to the Construction Specifications of on Infiltration Trenches: Minimum Standard 3.108. Placement of the filter box should be on an acceptable base (gravel, sand or compacted soil)to prevent the device from settling. The filter container should be backfilled and compacted in the same TB6-8 NMI° Technical Bulletin 6 Minimum Standard 3.11C manner as any precast concrete structure. The under drain leaving the box and connecting to the receiving conveyance system should be appropriately supported to prevent deflection during backfilling operations and sealed at the connection points to prevent leakage. 'Maintenance and Inspection Guidelines' The manufacturer provides for the inspection, care and maintenance of the Filterrallvi device for the first two years. After this initial two year period, the owner/operator of the system should follow all of the manufacturer's maintenance and inspection guidelines. In general, annual routine inspection and maintenance activities required are of a similar nature to any landscaped area and would include removal of trash, debris and sediment, replenishment of the mulch, and care or replacement of plants. The plant material requires no special care or attention once it has acclimated. Annual maintenance and care of the plants in a 6'x6' FT may require using one bag of mulch, a hand full of all- purpose fertilizer(optional)and 20 minutes of time. Fertilization of the plants is optional since the system receives adequate nitrogen, organics and phosphorus from the runoff. During extreme droughts the plants may need to be watered in the same manner as any other landscape material. In the event of a chemical spill all of the soil and plants should be removed and properly disposed and replaced with new uncontaminated filter media and plants. Manufacturer Contact: Mr. Terry Siviter Americast Inc. Phone: 804 798 6068 / Web site: www.americastusa.com TB6-9 Noe. Nue i. Kip Mumaw " ti Balzer and Associates_ Inc_ ' F _ s` "E 1561 Commerce Road, Suite 401 = ( , , 9 t Verona, VA 24482 July 17, 2009 PIan Review of Filterra® Collins Medical Center, Albermarle County, VA Dear Sirs Thank you for submitting the revised plans on 15 July 2009 for our review of the Collins Medical Center project. Filterra® structures Fl (6x6) and F2 (4x6) were studied for; • Planned Filterra® box size • Filterra® contributing drainage area meeting project's regional sizing specification • Spot elevations (TC) for Filterra® and bypass relief • Filterra® invert elevations are 3.5' below TC • Filterra® invert elevations are higher than effluent invert elevations • The bypass is lower than the Filterra® elevation (spot elevations) • The grading pattern encourages cross linear flow and not head-on flow • The Filterra® outlet drain pipe is sized correctly and exits perpendicular to the wall • For any conflicting structures such as stoup drain pipes below Filterra® • For most efficient placement of Filterra® units The plan review concluded that the Filterra® structures listed above were sited and sized appropriately to treat stormwater to our published specifications_ Operational consistency with these specifications is contingent upon the stormwater units being installed correctly and according to the plans, as well as regular maintenance being performed. Installation Help documents will be forwarded to the Buyer at time of order. The Filterra®Installation, Operation and Maintenance Manual will be made available upon request. Yours sincerely • �lcr� Dean Baddorf Engineer Support Manager it Filterra® Bioretention Systems • Manufactured by Amencast T: (804)798-6068 113.1\11 l ERIC/ ,S 11352 Virginia Precast Road F: (804)798-8400 not iast ccn,.r€te.concrete sotutions Ashland,VA 23005 E: design @filterra.com www.filterra.com ' Job File: J:\52009\S090001r7�COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP_PPW • Rain Dir: J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\ JOB TITLE Project Date: 7/17/2009 Project Engineer: WKM Project Title: Watershed Project Comments: S/N: 121D02A2E190 Balzer and Associates, Inc. PondPack Ver_ 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 NIS Table of Contents ii • `' Table of Contents (continued) *********************** POND ROUTING *********************** POND 1 Pond E-V-Q Table 7.01 POND 1 OUT 2 Pond Routing Summary 7.03 POND 1 OUT 10 Pond Routing Summary 7.04 ****************** RATIONAL METHOD CALCS ******************* SUBAREA 1 2 Mod. Rational Graph 8.01 SUBAREA 1 10 Mod. Rational Graph 8.02 SUBAREA 1 POST C and Area 8.03 S/N: 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 Type. . . . Rational Storms Page 2.01 Name. . . . ALBEMARLE File. . . . J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\ Title_ _ . Project Date: 7/17/2009 Project Engineer: WKM Project Title: Watershed Project Comments: I-D-F DESIGN STORM SUMMARY Storm Queue File,ID = ALBEMARLE Storm Tag Name = 2 File: Type = : I-D-F from e, b, d coeff. e Coefficient = .8200 b Coefficient = 49.0200 d Coefficient = 10.5000 Storm Frequ. = 2 yr Storm Tag Name = 10 File: Type = : I-D-F from e, b, d coeff. e Coefficient = .7300 b Coefficient = 46.9500 d Coefficient = 9.5000 Storm Frequ. = 10 yr Storm Tag Name = 25 File: Type = : I-D-F from e, b, d coeff. e Coefficient = .6600 b Coefficient = 40.1100 d Coefficient = 7.7500 Storm Frequ. = 25 yr Storm Tag Name = 100 File: Type = : I-D-F from e, b, d coeff. e Coefficient = _5500 b Coefficient = 31.0900 d Coefficient = 5.0000 Storm Frequ. = 100 yr S/N: 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver_ 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 NINO' Type. _ . . Tc Calcs Page 3.02 ••• Name. . . . SUBAREA 1 Tag: POST J:\S2009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP_PPW Tc Equations used. .. ___= User Defined --- Tc = Value entered by user Where: Tc = Time of concentration S/N: 121D02A2E190 Balzer and Associates, Inc. PondPack Ver_ 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 Type. . . . Time-Elevl Page�4.02 Nei * • Name. . . . POND 1 OUT Tag: 10 Event: 10 yr File_ . . . J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP.PPW Storm. . . e, b, d Tag: 10 TIME vs. ELEVATION (ft) Time j Output Time increment = 1.00 min min j Time on left represents time for first value in each row. .00 j 45.80 45.90 45.96 46.04 46.11 5.00 46.19 46.27 46.34 46.41 46.47 10.00 46.53 46.59 46.64 46.70 46.75 15.00 46.81 46.86 46.91 46.97 47.02 20.00 47.07 47.13 47.18 47.23 47.29 25.00 47.34 47.40 47.46 47.52 47.59 30.00 47.65 47.70 47.73 47.74 47.73 35.00 47.70 47.68 47.66 47.64 47.62 40.00 47.60 47.58 47.57 47.55 47.53 45.00 47.52 47.50 47.48 47.47 47.45 50.00 47.44 47.42 47.41 47.39 47.38 55.00 47.37 47.35 47.34 47.33 47.31 60.00 47.30 47.29 47.27 47.26 47.25 65.00 47.24 47.22 47.21 47.20 47.19 70.00 47.18 47.16 47.15 47.14 47.13 75.00 47.12 47.11 47.10 47.08 47.07 80.00 47.06 47.05 47.04 47.03 47.02 85.00 47.01 47.00 46.99 46.98 46.97 90.00 46.96 46.95 46.94 46.93 46.92 95.00 46.91 46.90 46.89 46.88 46.87 100.00 46.86 46.85 46.84 46.83 46.82 105.00 46.81 46.80 46.79 46.78 46.77 110.00 46.76 46.75 46.75 46.74 46.73 115.00 46.72 46.71 46.70 46.69 46.68 120.00 46.67 46.66 46.66 46.65 46.64 125.00 46.63 46.62 46.61 46.60 46.59 130.00 46.59 46.58 46.57 46.56 46.55 135.00 46.54 46.54 46.53 46.52 46.51 140.00 46.50 46.49 46.49 46.48 46.47 145.00 46.46 46.45 46.45 46.44 46.43 150.00 46.42 46.41 46.41 46.40 46.39 155.00 46.38 46.37 46.37 46.36 46.35 160.00 46.34 46.33 46.33 46.32 46.31 165.00 46.30 46.30 46.29 46.28 46.27 170.00 46.27 46.26 46.25 46.24 46.24 175.00 46.23 46.22 46.21 46.21 46.20 180.00 46.19 46.19 46.18 46.17 46.16 185.00 46.16 46.15 46.14 46.13 46.13 190.00 46.12 46.11 46.11 46.10 46.09 195.00 46.09 46.08 46.07 46.06 46.06 200.00 46.05 46.04 46.04 46.03 46.02 205.00 46.02 46.01 46.01 46.00 45.99 210.00 45.98 45.97 45.96 45.96 45.95 S/N: 121D02A2E190 Balzer and Associates, Inc. PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 Type. . . _ Vol: Pipe Page 5.01 ,r', Name. _ _ . POND 1 • • / File. . _ . J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP_PPW COMPUTED VOLUMES FOR A PIPE US Invert Elev.= 46.00 ft DS Invert Elev.= 45.80 ft Barrel Length = 110.00 ft Computed Slope = .001818 ft/ft Diameter = 24.00 in # of Barrels = 3.00 Slice Width = 1.00 ft Vertical Incr. = .10 ft Perpendicular Wetted Filled Perpendicular Total Elevation DS Depth DS Area Length Length US Depth US Area Volume (ft) (ft) (sq.ft) (ft) (ft) (ft) (sq.ft) (cu_ft) 45.80 .00 .0000 _00 .00 .00 .0000 0 45.90 .10 _0571 55.00 .00 .00 _0000 4 46.00 .20 .1613 110.00 _00 .00 .0000 21 46.10 _30 _2929 110.00 .00 _10 .0587 55 46.20 .40 .4444 110.00 _00 .20 .1635 97 46.30 .50 .6110 110.00 .00 .30 _2955 147 46.40 .60 .7893 110.00 .00 .40 .4473 201 46.50 .70 .9765 110.00 .00 .50 .6142 259 46.60 .80 1.1699 110.00 .00 .60 _7927 320 46.70 _90 1.3675 110.00 .00 .70 .9799 383 46.80 1.00 1.5672 110.00 .00 .80 1.1735 448 46.90 1.10 1.7668 110.00 .00 .90 1.3711 513 47.00 1.20 1.9646 110.00 .00 1.00 1.5708 578 47.10 1.30 2.1582 110.00 .00 1.10 1.7705 643 47.20 1.40 2.3456 110.00 .00 1.20 1.9681 706 47.30 1.50 2.5243 110.00 .00 1.30 2.1617 767 47.40 1.60 2.6914 110.00 .00 1.40 2.,.3489 825 47.50 1.70 2.8435 110.00 .00 1.50 215274 880 47.60 1.80 2.9759 110.00 .00 1.60 2.6943 929 47.70 1.90 3.0813 110.00 .00 1.70 2.8461 972 47.80 2.00 3.1416 110.00 .00 1.80 2.9781 1006 48.00 2.00 3.1416 110.00 110.00 2.00 3.1416 1037 S/N: 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 • st♦ Type. . _ _ Outlet Input Data Page 6.02 Name. . __ Outlet 1 File. . . . J:\S2009\50900017 COLLINS MEDICAL CENTER\CIVIL\CPL CULATIONS\BMP.PPW OUTLET STRUCTURE INPUT DATA Structure ID = 00 Structure Type = Orifice-Circular # of Openings = 1 Invert Elev. = 45.80 ft Diameter = 2.00 in Orifice Coeff. _ .660 Structure ID = WO Structure Type = Weir-Rectangular # of Openings = 1 Crest Elev. = 47.80 ft Weir Length = 4.00 ft Weir Coeff. = 3.000000 Weir TW effects (Use adjustment equation) S/N_ 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 Type. . . . Pond E-V-Q Table Pagell .01 rt Name. . . . POND 1 ,, File. . . . J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP.PPW LEVEL POOL ROUTING DATA HYG Dir = J:\52009\S0900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\ Inflow HYG file = NONE STORED - POND 1 IN 2 Outflow HYG file = NONE STORED - POND 1 OUT 2 Pond Node Data = POND 1 Pond Volume Data = POND 1 Pond Outlet Data = Outlet 1 No Infiltration INITIAL CONDITIONS Starting WS Elev = 45.80 ft Starting Volume = 0 cu.ft Starting Outflow = .00 cfs Starting Infiltr. = .00 cfs Starting Total Qout= .00 cfs Time Increment = 1.00 min Elevation Outflow Storage Infilt. Q Total 2S/t + 0 ft cfs cu.ft cfs cfs cfs 45.80 .00 0 .00 .00 .00 45.90 .01 4 .00 .01 .13 46.00 .03 21 .00 .03 .74 46.10 .05 55 .00 .05 1.86 46.20 _06 97 .00 .06 3.30 46.30 .07 147 .00 .07 4.95 46.40 .07 201 .00 .07 6.77 46.50 .08 259 _00 .08 8.72 46.60 .09 320 .00 .09 10.76 46.70 .10 383 .00 .10 12.88 46.80 .10 448 .00 .10 15.03 46.90 .11 513 .00 .11 17.21 47.00 .11 578 .00 .11 19.39 47.10 .12 643 .00 .12 21.54 47.20 .12 706 .00 .12 23.66 47.30 .13 767 .00 .13 25.70 47.40 .13 825 .00 .13 27.65 47.50 .14 880 _00 .14 29.46 47.60 .14 929 .00 .14 31.12 47.70 .15 972 _00 .15 32.55 S/N: 121D02A2E190 Balzer and Associates, Inc. PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 '41.114f 'VII I le 1( Type. . . . Pond Routing Summary Page 7.03 Name_ . _ . POND 1 OUT Tag: 2 Event: 2 yr File. . . . J:\S2009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP.PPW Storm_. _ e, b, d Tao: 2 LEVEL POOL ROUTING SUMMARY HYG Dir = J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\ Inflow HYG file = NONE STORED - POND 1 IN 2 Outflow HYG file = NONE STORED - POND 1 OUT 2 Pond Node Data = POND 1 Pond Volume Data = POND 1 Pond Outlet Data = Outlet 1 No Infiltration INITIAL CONDITIONS Starting WS Elev 45.80 ft Starting Volume = 0 cu_ft Starting Outflow = .00 cfs Starting Infiltr. _ .00 cfs Starting Total Qout= .00 cfs Time Increment = 1.00 min INFLOW/OUTFLOW HYDROGRAPH SUMMARY Peak Inflow = .56 cfs at 5.00 min Peak Outflow = .12 cfs at 26.00 min Peak Elevation = 47.14 ft Peak Storage = 666 cu_ft MASS BALANCE (cu.ft) Initial Vol = 0 + HYG Vol IN = 808 - Infiltration = 0 - HYG Vol OUT = 807 - Retained Vol = 1 Unrouted Vol = 0 cu_ft (_0000 of Inflow Volume) S/N: 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver_ 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 '4111.0V NNO Type. . . . Mod. Rational Graph Page 8.01 1, Name. . _ . SUBAREA I Tag: 2 Event: 2 yr J:\52009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP.PPW Storm. . _ e, b, d Tao: 2 MODIFIED RATIONAL METHOD Graphical Summary for Maximum Required Storage ---- Method I Q = CiA * Units Conversion; Where Conversion = 43560 / (12 * 3600) ********************************************************************** * RETURN FREQUENCY: 2 yr 1 Allowable Outflow: _48 cfs * 'C' Adjustment: 1.000 1 Required Storage: 391 cu.ft * Peak Inflow: _56 cfs * * .HYG File: 2 ********************************************************************** Q I Td = 24.00 min 1 Return Freq: 2 yr / Approx. Duration for Max_ Storage / C adj _factor:1.000 Tc= 5.00 min I = 5.1797 in/hr Area = .310 acres Q = 1.08 cfs Weighted C = .668 Adjusted C = .668 I � - Required Storage .-- 391 cu.ft Td= 24.00 min I = 2.6876 in/hr x x. x x x x xlx x x x x x x x x x x Q = .56 cfs 1 j x x o Q = .48 cfs . x o x (Allow_Outflow) x _ o x o NOT TO SCALE x x o o _ x 24.72 min T S/N: 121D02A2E190 Balzer and Associates, Inc. PondPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 e�. Type. . . . C and Area Page 8.03 ,... Name. .. . SUBAREA 1 Taa: POST File_ __ . J:\S2009\50900017 COLLINS MEDICAL CENTER\CIVIL\CALCULATIONS\BMP_FPM RATIONAL C COEFFICIENT DATA Area C x Area Soil/Surface Description C acres acres .6680 .310 _207 WEIGHTED C & TOTAL AREA ---> .6680 .310 _207 S/N: 121D02A2E190 Balzer and Associates, Inc. PcndPack Ver. 09.00.077.00 Time: 10:19 AM Date: 7/17/2009 Appendix A A •1� Index of Starting Page Numbers for ID Names A ALBEMARLE._ . 2.01 0 Outlet 1._ _ 6.01 P POND 1... 5.01, 7.01 POND 1 OUT 2... 4.01, 7.03, 4.02, 7.04 S SUBAREA 1 2. __ 8.01, 8.02, 3.01, 8.03 N Watershed. . . 1.01 S/N: 121D02A2E190 Balzer and Associates, Inc_ PondPack Ver_ 09.00.077.00 Time: 10:19 AM Date: 7/17/2009