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20081213 Ver 2_Stormwater Info_20090702
? ? ? Kimley-Horn and Associates, Inc. July 1, 2009 Mr. Joseph Gyamfi NCDENR, Department of Water Quality 2321 Crabtree Blvd, Suite 250 Raleigh, NC 27604 Subject: South Tract City Boulevard Development Charlotte, North Carolina Our Ref: 018253029 DWQ Ref: 08-1213 V 2. Dear Mr. Gyamfi: JUL ?[R@[Emgo 9, 2009 WETLANDS AND SToRMVtsArrR BRANCH On behalf of our client, Crescent Resources, LLC, we are writing in response to your letter dated June 3, 2009. It is our understanding that DWQ has approved the revised stormwater management plans with the condition that we provide a description of the changes and supporting documentation. The revisions to the previously approved set of plans include an increase in spillway width and revised control structure elevations for the 10- and 25-year, 6-hour storm events. Per your request, we hereby submit the following items: • Two stormwater management calculation packages We trust this meets your needs at this time, but please feel free to contact me at (704) 319-7699 with any questions or concerns. Sincerely yours, KIMLEY-HORN AND ASSOCIATES, INC. Beverly Ro^?m, EI :brr (KACHL LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Correspondence\L062609.D WQ.BRR_ST.doc) NCDF?NR North Carolina Department of Environment and Natural Resources Division of Water Quality Bevedy Eaves Perdue Coleen H. Sullins Governor Director June 3, 2009 Dee Freeman Secretary Mecklenburg County DWQ EXP #t 08-1213v2 Mr. David Niekamp Crescent Resources, LLC 400 S. Tryon Street, Suite 1300 Charlotte, NC 28285 Subject Property: South Tract City Blvd Development APPROVAL OF REVISED STORMWATER MANAGEMENT PLAN (SMP) Dear Mr. Niekamp, la? R-9i E=5 l1 JUL 2 2009 DENR - WATER QUALITY WETLANDS AND STORMVIAI A BRANCH On June 2, 2009, the Division of Water Quality (DWQ) received one set of revised (updated) stormwater management plans (SMP) for the subject project from Ms. Beverly Rosenbloom of Kimley-Horn and Associates, Inc. The SMP, with last revision dated May 28, 2009, was. revised to satisfy the Phase 11 requirements of the City of Charlotte's Stormwater Ordinance. The DWQ has reviewed the revised SMP and found no significant changes to the one previously approved on December 3, 2008 except for a slight increase in drainage areas. The DWQ therefore approves the newly revised plans to satisfy the stormwater condition required by the 401 Water Quality Certification issued by the DWQ on August 25, 2008 for the subject project. You are however required to meet the additional conditions 1 through 4 in the approval issued on December 3, 2008. In addition, within 30 days of receipt of this letter, please send a detailed description of all changes, if any, made to the previous SMP along with supporting documents including design calculations. This letter completes the review of the Division of Water Quality under Section 401 of the Clean Water Act. If you have any questions, please contact Joseph Gyamfi or Lia M. Gilleski at 919-733-1786. Sincerely, / Cynd€ Karoly, Supervisor 401 Oversight/Express Review Program CBKJjg cc: USACE Asheville Regulatory Field Office DWQ Mooresville Regional Office File Copy Bev Rosenbloom, Kimley-Horn, 4651 Charlotte Park Dr., Suite 300, Charlotte, NC 28217 401 Oversight/Express Review Permitting Unit 1650 Mail Service Center, Raleigh, North Carotin 27699-1650 Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604 Phone; 919-733-1786 t FAX: 919-733-6693 Internet: http:llh2o.enr.state.nc.uslncwetlandsl .One Mma!!y An Equal Opportunity 1 Affirmative Action Employer 0 Revised Stormwater Management Calculations: South Tract City Boulevard Development Prepared for: Crescent Resources, LLC 400 S. Tryon Street, Suite 1300 Charlotte, North Carolina 28202 Prepared by: Kimley-Horn and Associates, Inc. 4651 Charlotte Park Drive, Suite 300 Charlotte, North Carolina 28217 Kimley-Horn and Associates, Inc. ag @IN O V/ [!D J U L 2 2009 DENR - WATER QUALi fY WETLANDS AND sTORWATaft ©Kimley-Horn and Associates, Inc. 2008 018253026 SOUTH TRACT CITY BOULEVARD DEVELOPMENT CHARLOTTE, NORTH CAROLINA REVISED STORMWATER MANAGEMENT CALCULATIONS Prepared for: Crescent Resources, LLC 400 S. Tryon Street, Suite 1300 Charlotte, North Carolina 28202 Prepared by: Kimley-Horn and Associates, Inc. 4651 Charlotte Park Drive, Suite 300 Charlotte, North Carolina 28217 CARO?//i Fs S/ - A r. • .F ¢ i??/y?'p' ?O ?\3 vq March 2009 KHA Ref: 018253026 TABLE OF CONTENTS OVERVIEW SITE MAPS SITE VICINITY MAP SCS SOIL SURVEY FEMA FIRM PANEL WATERSHED MAPS PRE-DEVELOPMENT WATERSHED MAP POST-DEVELOPMENT WATERSHED MAP WATER QUALITY WET POND CALCULATIONS ANTI-FLOTATION DEVICE CALCULATIONS VOLUME AND SURFACE AREA TABLES WET DETENTION BASIN SUPPLEMENT FORMS WATER QUANTITY CURVE NUMBER CALCULATIONS TIME OF CONCENTRATION CALCULATIONS HYDROCAD HYDROLOGY REPORT ¦ Jl vnmw,glCx MAlvACiCA&NT CALCULATIONS South Tract city Boulevard Development, Charlotte, NC i Background OVERVIEW This report contains the approach and results of a stormwater analysis conducted for the South Tract City Boulevard Development. The 41-acre project site is located in the south east quadrant of the interchange of Interstate 85 and City Boulevard in the City of Charlotte (see vicinity map). The site has been mass graded per City of Charlotte permit number GRS-2007223. Existing Conditions The existing on-site conditions (before mass grading) consisted of woods and meadow therefore this ground cover was used in the analysis. The site topography varies from elevation 770 ft to elevation 720 ft. Site runoff discharges into an existing stream in the middle portion of the site. This stream drains to a culvert under City Blvd. Floodplain/Floodway The proposed site does not lie within a 100-year floodway boundary as determined by FIRM Panel # 3717900070C. Water Quality Water quality treatment by means of permanent Best Management Practices (BMP's) will be provided using two wet ponds as treatment. The ponds are designed to treat the first inch of runoff per the Stormwater Model Ordinance for North Carolina and will draw down over a period of two to five days. Wet Detention Basin 1 and Wet Detention Basin 2 have been designed to provide a minimum 90% average annual removal of Total Suspended Solids (TSS). Water Quantity The proposed wet detention ponds have been designed to address the water quantity requirements to match pre- and post-development peak runoff rates for the 1-year, 24-hour storm events. (These ponds will also control the peak runoff rates for the 10- and 25-year, 6-hour storm events per the City of Charlotte rezoning notes on Petition 2006-155. However, these water quantity requirements will be reviewed by the City of Charlotte when the site develops.) The 100-year, 24-hour storm event was checked for 6" of freeboard at the top of bank. Results Pre-development 1-yr, 24-hr storm Post-development 1-yr, 24-hr storm DA-1 4.17 cfs 1.30 cfs DA-2 1.46 cfs 1.37 cfs STORMWATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, NC Conclusion The proposed wet detention basins were designed using methods prescribed by the aforementioned resources. HydroCAD software was utilized to evaluate the pre-development and post-development flow rates. HydroCAD utilizes TR-55 methods of calculating times of concentration (based on sheet, shallow concentrated, and channelized flows) and SCS curve number method of generating hydrographs (results are provided in Appendix C). Based on the analyses provided herein, the proposed system will be adequate to address the stormwater requirements of the North Carolina Department of Environment and Natural Resources, Division of Water Quality. 61 uRMWAIER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, NC SITE MAPS STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina Elm0 PARCEL J ROADWAY VICINITY MAP FIGURE Kimley-Horn and Associates, Inc. NTS ' TM DOaM7WTMT. 700E7MER MIN THE o(INCOM AND DESIGNS PRESENTED NM1. AS AN NSIRUENT OF SFRNCE, IS 1117DOW OILY FDR THE PURPDSE AND CL ENT FOR *IM)H IT WAS PREPARED. RE7TSE OF AND WROPER ADJANCE ON THIS DGCLUINT NTTNDUT 1NBTTEN AU7MONZATIDN AMC ADAPTATMGN BY KR EY-NGRN AND ASSWATES. NG. SMALL K NTTNGUT UA9UTY 70 KU EY_MM AND ASSOCIATES ND. K-\O L_LDEV\018253 Crescent\026 Bel to\Bel to Storneater Mann rent Plan\Calculatlons\Parcel J\SoNs and Vic"t .de Y Y - r c t r e R ('7t .. 41, r . , ? k r t F R ` f ° 1 a k . . 4i. .? S`? h _ = 1 , 7 i { y4 f r wry ??. 6 'd _ -A ti- A / 6` r'J le.. t :uf ? 15 ?z } Ore Mecklenbuf s. North Carolina -01 0?0 PARCEL J ROADWAY SCS SOIL SURVEY FIGURE Kimley-Horn and Associates, Inc. INTS 2 - -1. .,.,.?,.?.. -1. - V,w.,sr,a "' DERC 6 P¢--K AS AN MI M WT OF W MM b MMOED OM_Y FOR 1W PURPM AND a "T FOR MOM R WAS PREPARED. IIEUSE OF AND NA4W R NEUAMX ON TMS DOCUMENT MTNOUT MBTHN AU111oR1MTM AND ADAPTA7M BY M LEY-MM AND AMMATM NC. WALL K NnNOUT UAMUW TO KIMU 6M AND ASSMAMk NG H d w d CD`? C ` O O Lo Lo d n O T [ 1 iD+ C W J O U Q U CL o CI) >LL L H Q C C O d V 0 X m Wa W 5 o N Z ./4 N d m D ? C LL j F S o u ? C y o Nv j Co ti eg° m•a ?C= °u W i (y J "'+ m < S Z ?J 'y 1 C R I d >r ? ? 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V � � 01 4-1 4-1 •`i �.�-Oji-`;�, ••%! `, 1• �t'` 'moi_ ...�--'-�', �'� \\ b N O tY1 Esti\�\.✓ C�; v syo\\\.\:ti PRE-DEVELOPMENT WATERSHED MAP STORM WATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina ? - } b saOisln3a su,3wwoO OmO Obswa>sal3 aid saolsln3a 3>,vO swum 'ox t S9Z9Z 3N'31101iJVH0 00a 31S'13381SNOAHIS00y Z9Z9Z'VNIIOUVO HiHON A1Nf100 •J21f18N31N03W '31101L1VH0 I°v e -6 su,a'svoo onaaNnOkI Q ooas a3asr,Olslnaa s ZM Z OTI'S3o8nOS381N30S3110 OA19 A110 0NV Sal dvw d3av a a 4 N 1 " - ? m BEWNIV601N31MO13A30 38d m o ?° w a $Mnd 1N3WBGVNVN u31rMNVO.LQ • y yy ? a In aarnos A113 iarai HIM ? b34s 8I'3.0 a :fx3ro xosoua :nlu ?' S a VY' ((Y` pA,1 7 M w o ! ' I _ Q /ff j 1 '& : I 10 j•r y ? _??f ? ?: ? ? gg \ j t: e ?? J Y L x u - Q Z Aflt? V II id VI 0 ? MU? 11 - ?.' r ss ?..• x I r r I 3•. • 4ClitEF? ,? , X34 , ;;I t d u Fr , { " Y- • x +x4 - - . , - f • ?. ,?. P` .. .. 1 : i s 1 Ili i _ wit i , I II I a a 4 ' .ii ,ii / F A f Z 1 OD - O f C.4 0 s NQZL6 U N I ¦ ' ' r V I I ? F... .1 I I t #r I? I g??i ?¦ 1 r '3 ?e I 4 i I : 1 ------------------ 40,M 4g { p + !' y:_ ?ip4 _ - it _?n - t`3 MS? \ I Sn 4 4 A wo•iw•.•. ywa B wCf•'G - YObi Vi w°:woy bwel-oi-YOOC•buWtl\? wad\•:°NbMMe\?•k 1 ?+bo:ulS ?1? IS o 4y] p p 1 L) V) rp x a? a _ I H 9Ze\Iww•u CCxY?b\n3m w?\:• POST-DEVELOPMENT WATERSHED MAP STORMWATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina b c } SNOISA3a diva 'ox GSN9 ON'311O18VHO Z9ZOZ'VNIlO?JVO HIHON N MMU k OM 31S '133211S NOAa1'S OOC UNnoo odn8N31NO3W'3llO18VHO oll'S3oanos3a 1N33S3ao ?'OA18 AlIO ONV SS-I dVW VBUV 9E)VNIVNO _ ?r a a o `., I I lOv8i HinOS 31VE)138 k S 1 ! € r?o 9 w ff SNV1d 1N3W3011NVW U31rMWVOJS 1 " . ?? ? 1? ?! o ""'",I I a sajuf lom J K2DSHIJ V3LSVW 3LV0138 ?LL $ a 5 U 4rum ua?ma B @ II!, milli, 1 Z Z Z !ry W \ Q J/ ?? 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WET DETENTION BASIN Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 10/8/2008 Revised by: BRR Date: 10/27/2008 Revised by: BRR Date: 11/14/2008 Site Information Sub Area Location: Drainage Area 1 Drainage Area (DA) = 7.44 Acres Impervious Area (IA) = 6.43 Acres Percent Impervious (1) = 86.4 % Required Surface Area Permanent Pool Depth: 4 ft SA/DA = 4 (90% TSS Removal via Pond) Min Req'd Surface Area = 12963 sf (at Permanent Pool) Required Storage Volume: Design Storm = 1 inch (Project Does Not Drain to SA waters) Determine Rv Value = 0.05 +.009 (I) = 0.83 in/in Storage Volume Required = 22357 cf (above Permanent Pool) Elevations Area (s.f.) Bank Elevation = 732.00 ft Top of Pond Elevation = 732.00 ft Temporary Pool Elevation = 727.70 ft 19,373 Permanent Pool Elevation = 726.00 ft 14,257 Shelf Beginning Elevation = 726.50 ft Forebay Weir = 728.00 ft Shelf Ending Elevation = 725.50 ft Sediment Cleanout Elevation = 718.00 ft Bottom Elevation = 717.00 ft Wet Basin Areas/Volumes (Elevation = 727.70) Area @ Top of Temporary Pool = 19373 sf (Elevation = 726.00) ' Area @ Top of Permanent Pool = 14257 sf Volume of Temporary Storage = 28586 cf Side Slopes of Pond = 3 :1 Side Slopes of Shelf = 1 0 :1 Side Slopes of Pond (below shelf) = 3 :1 Yes ( 14257 > 12963) sf Is Permanent Pool Surface Area Sufficient (yes/no)? Volume of Storage Provided 28586 cf Total Volume Sufficient (yes/no)? Yes Orifice Size = 2.30 inches WET DETENTION BASIN Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: Revised by: Date: Revised by: BRR Date: Site Information 4/1/2008 11/1412008 Sub Area Location: Drainage Area 1 Drainage Area (DA) = 7.44 Acres Impervious Area (IA) = 6.48 Acres Percent Impervious (1) = 87.1 % (Drainage Area) Orifice Sizing Q2 Days = 0.1654 cfs Q5 Days = 0.0662 CfS Orifice Size = 2.30 in Q orifice = 0.102 cfs Drawdown Time = 3.3 days (Flowrate required for a 2 day drawdown) (Flowrate required for a 5 day drawdown) (Diameter) less than 5 days (yes/no) ? yes greater than 2 days (yes/no) ? yes Orifice Equation: Q=CAgd(2gh) Q2 < Q < Q5 c=0.6 A9= Area of Pipe = n/4D2 g = gravity = 32.2 ft/s2 h = orifice head = 1/3 (TPE-PPE-1/2D) TPE = Temporary Pool Elevation PPE = Permanent Pool Elevation D = Diameter C Kirnley-Horn and Associates, Inc. WET DETENTION BASIN Project Information Project Name: KHA Project #: Designed by: Revised by: Revised by: Belgate - Southern Tract 018253026 BRR Date: 10/8/2008 BRR Date: 10/19/2008 BRR Date: 11/1412008 Site Information Sub Area Location: Drainage Area 2 Drainage Area (DA) = 25.11 Acres Impervious Area (IA) = 18.53 Acres Percent Impervious (1) = 73.8 % Required Surface Area Permanent Pool Depth: 4.35 ft SA/DA = 3.375 (90% TSS Removal via Pond) Min Req'd Surface Area = 36915 sf (at Permanent Pool) Required Storage Volume: Design Storm = 1 inch (Project Does Not Drain to SA waters) Determine Rv Value = 0.05 +.009 (1) = 0.71 in/in Storage Volume Required = 65095 cf (above Permanent Pool) Elevations Area (s.f.) Bank Elevation = 725.00 ft Top of Pond Elevation = 725.00 ft Temporary Pool Elevation = 720.60 ft 46,100 Permanent Pool Elevation = 719.00 ft 38,235 Shelf Beginning Elevation = 719.50 ft Forebay Weir = 722.00 ft Shelf Ending Elevation = 718.50 ft Sediment Cleanout Elevation = 712.00 ft Bottom Elevation = 711.00 ft Wet Basin Areas/Volumes Area @ Top of Temporary Pool = 46100 sf (Elevation = 720.60) ' Area @ Top of Permanent Pool = 38235 sf (Elevation = 719.00) Volume of Temporary Storage = 67468 cf Side Slopes of Pond = 3 : 1 Side Slopes of Shelf = 1 0 : 1 Side Slopes of Pond (below shelf) = 3 : 1 i Is Permanent Pool Surface Area Sufficient (yes/no)? Yes ( 38235 > 36915) sf Volume of Storage Provided 67468 cf Total Volume Sufficient (yes/no)? Yes Orifice Size = 2.90 inches WET DETENTION BASIN Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: Revised by: BRR Date: Revised by: BRR Date: Site Information Sub Area Location: Drainage Area 2 Drainage Area (DA) = 24.40 Acres Impervious Area (IA) = 18.30 Acres Percent Impervious (1) = 75.0 % (Drainage Area) Orifice Sizing Q2 Days = 0.3904 cfs (Flowrate required for a 2 day drawdown) Qs Days = 0.1562 cfs (Flowrate required for a 5 day drawdown) Orifice Size = 2.90 in (Diameter) Q orifice = 0.155 cfs Drawdown Time = 5.0 days less than 5 days (yes/no) ? yes greater than 2 days (yes/no) ? yes Orifice Equation: Q=cA9d(2gh) Q2 < Q < Q5 c = 0.6 Ay= Area of Pipe = Ti/4D 2 g = gravity = 32.2 ft/S2 h = orifice head = 1/3 (TPE-PPE-1/2D) TPE = Temporary Pool Elevation PPE = Permanent Pool Elevation D = Diameter 10/19/2008 11/3/2008 11/14/2008 Wmley-Han CC" and Associates, Inc. Pre vs. Post Runoff Analysis Composite Curve Number (CN) Project Information Project Name: Belgate - South Tract KHA Project #: 018253029 Designed by: BRR Date: 10/6/2008 Revised by: BRR Date: 11/14/2008 Revised by: Date: Drainage Area Name Drainage Location Cover/Soil Name (Type) Cover Description` Hydrologic Soil Group Curve # (CN)" Area (ac) Product of CN x area Composite Curve Number (CN) PRE-DEVELOPMENT DA-1 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 5.04 353 70 Meadow Good Condition B 71 5.04 358 71 10.08 711 70.5 DA-2 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 2.95 207 70 Mecklenburg, Enon, Wilkes Meadow Good Condition C 71 2.95 209 71 Cecil Meadow Good Condition i I B 58 10.69 620 58 Cecil Woods Good Condition B 55 10.69 588 55 27.28 1624 59.5 Total Pre-development Area = 37.36 POST DEVELOPMENT DA-1 POND 1 Impervious 98 6.43 631 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition (from City Blvd) C 73 0.29 21 73 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 0.71 53 74 7.44 704.63 94.72 Mecklenburg, UND DA-1 OUTFALL 1 Enon, Wilkes i Open Space - Good Condition C 74 0.90 67 74 0.90 66.60 1 74.00 DA-2 POND 2 Impervious i 98 15.40 1509 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 0.83 61 74 Cecil Open Space - Good Condition B 61 4.11 251 61 ! Roadway - Impervious I j 98 3.13 307 98 Mecklenburg, Enon, Wilkes Roadway - Open Space ( C 74 1.54 114 74 Cecil Roadway - Open Space B 61 1 0.10 I 6 61 25.11 2248.13 89.53 - UND DA-2 OUTFALL 2 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 2.96 219 74 Cecil Open Space - Good Condition B 61 2.97 181 61 5.93 400.21 67.49 Total Post-development Area = 39.38 Cover Descriptions per TR-55 Manual " From TR-55 Manual, Table 2-2 a & c I I K:\CHL_LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Calculations\South Tract\Stormwater Calculations_2008-10-06.xls 1 of 1 ANTI-FLOTATION DEVICE CALCULATIONS STORMWATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina run 121d% =11 Im NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS (per NCDENR Manual) Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 11/3/2008 Revised by: Date: Revised by: Date: Revised by: Date: Pond 1 Drainage Area Information: Drainage Area (ac) = 7.15 Flow (Q.) (cts) = 12.8 Storage Dimensions: Basin Side Slopes L : 1 ) = 3.0 Storage Depth "R" (ft) = 9.0 Top of Basin Elevation Temporary Pool Elevation Permanent Pool Elevation Bottom of Basin Elevation (3:1 max side slopes) Elev (ft) Area SF Cumulative Volume (CF) 732.00 27.972 730.00 23.807 124,239 727.70 16.459 77,934 726.00 11.541 54.134 723.00 7.735 25,220 720.00 3,846 7.848 717.00 1,386 0 Control Structure Length (in) = 48 Control Structure Width (in) = 36 Riser Area (so = 12.00 (Check dser geometry vs. area equation) Volume of Water Displaced (co = 108.0 Weight of Water Displaced (lb) = 6,739 Min. Required Weight of Anchor Block (lb) = 7,413 (1.1 factor of safety) Anchor Size: Width (If) = 4.4 Length (If) = 5.0 Height (If) = 4.00 Weight of Anchor (lb) = 7,709 O.K. > Minimum Required Weight Sizing of Emergency Spillway: 0, (cts) = 12.8 C6,._r (cts) = 12.8 (Riser ignored) Water Depth Over Spillway (ft) = 0.5 Spillway Length (ft) = 15.0 (10 ft minimum spillway length, Cw=2.7) Spillway Crest Elevation (ft) = 730.5 (1 ft min. above sediment storage depth) Freeboard (ft) = 1.04 (1 ft minimum) Page 1 of 1 Cc" ,k.. NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS (per NCDENR Manual) Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 11/32008 Revised by: Date: Revised by: Date: Revised by: Date: Pond 2 Drainage Area Information: Drainage Area (ac) = 23.90 Flow (05D) ids) = 16.7 Storage Dimensions: Basin Side Slopes LX: 11 = 3.0 (3:1 max side slopes) Storage Depth "R" (ft) = 7.0 Top of Basin Elevation Temporary Pool Elevation Permanent Pool Elevation Bottom of Basin Elevation Elev ft Area SF Cumulative Volume (CF) 725.00 60.143 723.00 53.616 332 340 720.70 39.312 225,473 719.00 31.750 165,071 716.00 22.055 84.363 714.00 17,794 44.514 711.00 11.882 0 Sizing of Antiflotation Block: Control Structure Length (in) = 48 Control Structure Width (in) = 36 Riser Area (so = 12.00 (Check riser geometry vs. area equation) Volume of Water Displaced (d) = 96.0 Weight of Water Displaced (Ib) = 5,990 Min. Required Weight of Anchor Block (lb) = 6,589 (1.1 factor of safety) Anchor Size: Width (If) = 4.1 Length (If) = 4.8 Height (If) = 4.00 Weight of Anchor (lb) = 6,896 O.K. - Minimum Required Weight Sizing of Emergency Spillway: 0. (ds) = 16.7 O,gµ,Y (ds) = 16.7 (Riser ignored) Water Depth Over Spillway (ft) = 0.5 Spillway Length (ft) = 40.0 (10 ft minimum spillway length, Cyr-2.7) Spillway Crest Elevation (ft) = 7237 (1 ft min. above sediment storage depth) Freeboard (ft) = 1.01 (1 ft minimum) Page 1 of 1 VOLUME AND SURFACE AREA TABLES STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina 5i E 0 E c Y N O O O N N N 0 0 co N ? N O ? N 0) N c o o t m (O 04 LO i O Cl) Q N 0 co 0 O 7 c co co m 0 E 2 c O E E n L M O Z 01 'a -0 u O n0 L L Q) a . Q? N a Y p a m •O O. c .N m co c 0 c 0J O W 3 E u tD Ln 01 0 r1 Ln lD 00 W LD n n 0 0 0 m 0 r- I Ln m y rn rn Q .--i N M -7 l0' m O O ; 0 _ lO 01 M V Ln M r•I W O N N .••1 O O tD V1 00 00 -i Ln .. to QO F- u ?o Ln n n u1 ti 0) to -?t O C 00 N n M 0) w V M N 0 O O ri r•1 N " N m 'T In tD 10 0 0 0 0 0 0 0 0 0 O W v 0 0 0 C o c o 0 0 0 j a O m co v m 0 01 m 0 :° IT m n Ln LO 0 0 0 0 0 L Q N M In o N 1 Ln -I 0) -I M N Q - . . N N m W 000 n 00 M O 1-1 N M a M to 10 N '•i n .-i n .1 n N n N n N n N n N n N n N n c a+ 0 0 c O O a c 10 O a d 0 y U c tJ E c 0) m v 0 O 0 E p O co N d 9 LD N n 00 a--I ci N r, CYI r? r-4 01 lO O 00 .-I Ln v E o N O O E o O > 0, O ++ O 7 N N c m LO N E N O a, O LL a U- 0 E N a ItT n Ln n O -I Ln CO i N LT lD -4 m m 00 r, n O Z U 0) O "l r oc 00 . lO V M c n a 0 O r•I Cn r-4 l71 n lD w 7 QU 0 0 M n ' L l r N M N N It T Lo n N V. -1 4 N M ' O N tT n '? > 1 M qr d Ln lD n 00 '-I ei N a--I 0 E O O1 N -, H -t N m N -' u) M Ln M m P, v N n m n O to `"I 00 O N O M M I 3 V O O M M lD O n n .-I ri ? O ,--I 01 00 00 W o0 01 .. ` N M ?' to n n n et 111 tD OD Ln l N r-4 N I N i O F U f0 0o 01 00 M lD n lD LO lD O 01 01 Ln n Ln N Ln Ln iq ` .-1 Ln m 00 Ln Ln n n n Ln d' 00 Ln V n r, m m N W M a LD 0O -1 a n n n O lD N -I d• Ln O V O) cY e O O O O r•I e•7 e-'1 r-I r-I N N m ;r -{ tY Ln Ln Ln l0 o O o 0 o O o 0 0 0 o O o O O O o O O J Q N 0, w m 00 i.-1 O 00 n lD V to M 00 a to m Ln m 111 m Ln Ln ?`"I N 00 O O P, M M O N M o 0 m Ln N P, Z O L Q` M .-1 O N n N 00 m O Ln m w n n n n n n m 00 Lr) r-I -1 m -4 -I 'I W 1 m Q1 -1 a) Ol - 00 00 m 00 111 0) . e - r , 4 N N N N _Z Q 00p n 00 O1 O ? q N M I Ln U1 LO to n n 00 M O .-1 N m ' 4 '-I e-1 N N N N N N In N w N n N N M M M N n n n n n n n n n ^ n ^ n N n n n n n c a+ O o 0 o a0 v N a a c G, p U p C V) m U E C E c O L o p O (U y0 m O CL E O o o i- a , r m a, m a F- Ln r~-I V a--I 01 n M N In tD N 00 -T Ln v E LL 3 v > N 0 Y ?+ In c c N c c _0 m m N c L •1/1 a a m o ti c d .76 x° E Y m f0 i a d 3 H C LO 0) O U L6 a? w 3 O CO c O 000 N N N 0 co 0 r r N O r N N N (D N CI) to Q' co cIj co co O R 0) Y T M a"i v O Z d v v C Y O- C a, v u D_ OD !2 L^ (D m 2 p K fY D Y a` N C N m c O I_ a, v p N 3 E M LD N V Ln n M W LD U 7 O O V M n U1 (7 00 '4 LA Lfl Q? N U1 00 N w e-1 ? M M rl ei N N m M a M M LD N r-I N LD M 7 V O O N W N M M 00 P•1 M q;T 01 L)1 Ln - LD ym O U 16 O OO M M 00 r-I e-1 M 1-1 r-I " " N I-T LD 0 O -41 00 00 Ln LD n o0 m O N M Ip 0 0 0 0 0 0 e-I rl a--I ei W x 0 0 0 0 0 0 0 0 0 0 Z Q O Ln Ln O w o) oo M .-I r1 w 0) w- 00 ^ " rn O N M 00 00 o0 Q ? -i O " N LD W N 00 Q e N N m M m M 'T V CT Ll1 Ln ul lD W to O r1 N M N LD n 00 0) N f\ n f\ n n f\ n n n n C 3 O O 0 ° C 0 a v o O p U N C C O O 0) E /6 p O CO a N o\° tD Ln v 00 a--I 7! O N 0 O M 00 M 00 II a) a) CL O N 7 > 0) O Y _O > c N C m E a) U- a U. N M 01 M n Ln - I O r-1 " m LD N n LD C) LO w n I-T 01 LD N * 0) '-1 Ln 01 m ei t0 t\ lp et n O O O Q 0 0 ^ Ln m m U7 M m v r1 O O m 00 00 O CF H O rl m M S 0 M 00 V > a-1 M Lfl n 01 ti -I ? L D 0 -f-1 m 0 0 0 0 * r eI r1 r-1 N N N N M m 1* V w m n ? 't t10 LD 00 M O N m LD LD m m n E r- n 10, r` Ln " n P N Ln r1 00 00 N M M 7 U O O n n 00 m " V Ln co rn O r-1 LD 00 O N v ? w -e 10 > e i e-I N N N a--I rl rl N N 1-1 ? Ln Ln ui +•' O F U f0 00 Ln 00 Ln t, M O O 00 m m LM M 0 O m ri r? N LD r1 00 LD LD n a LD 00 Ict w 00 lD 00 O U1 O W t\ r-I LD O Lf) O Ln r-I M N N 'I Ln 00 Ln m O 00 N M M I;t Lf1 U1 LD LD n 00 O O O -! N M (n ` 0 0 0 0 0 0 0 0 0 O O r! e-I N a--1 rl r1 e-1 J Q N 00 LD 00 0) Ln M Ln r1 ei O O ri n O 0) N LD O M 0 Z 00 n r` rn ? 01 oo 0 O lD N N m c7 fl, LA n M 0) n N O 1-4 N M V, .-1 LD Lf1 00 ri Q `-' -4 1 M -i m -1 n m N V LD N -1 Ln T w r? O M w O a r a e e-1 rl N N N N M M I;r v Ln Ln Ln LD Z N rl N M ? Ln LD n 00 Lr) 0) Ln O t0 -1 N M Ln m rl 1-4 r1 r1 r1 rl r1 r1 00 r-I m r4 O N N N N N ? n N n n n n n n ^ n ^ n ^ N n n n n r Y O O O C O C f0 O O w O O a a i N o D_ O. p U 0 C N `u E C E O) C O ILO y O N O Y O. m p E + E o b cu 0 CO N l tl O_ O H n V r1 n M M 01 N OO C* M N a) C ? v Q > h _O C C h v a) °' c c ? m fo Ln N I C (v a, m a D_ co WET DETENTION BASIN SUPPLEMENT FORMS STORADVA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina Permit No A=*A i NCDENR (to be provided by DWQ) O?O? W A TE9OG O T STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WET DETENTION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information. 1. PROJECT INFORMATION Project name Belgate Southern Tract Contact person Beverly Rosenbloom, El Phone number 704-319-7699 Date 3/31/2009 Drainage area number 1 !!. DESIGN INFORMATION Site Characteristics Drainage area 324,086.40 ft2 Impervious area 280,090.80 ft % impervious 86.42 % Design rainfall depth 1.00 in Storage Volume: Non-SR Waters Minimum volume required 22,357.00 ft3 Volume provided 28,586.00 ft3 Storage Volume: SR Waters 1-yr, 24-hr runoff depth in Pre-development 1-yr, 24-hr runoff ft3 Post-development 1-yr, 24-hr runoff ft3 Minimum volume required ft3 Volume provided ft3 Peak Flow Calculations 1-yr, 24-hr rainfall depth 2.58 in Rational C, pre-development 0.28 (unitless) Rational C, post-development 0.88 (unitless) Rainfall intensity: 1-yr, 24-hr storm 0.12 in/hr Pre-development 1-yr, 24-hr peak flow 2.63 ft3/sec Post-development 1-yr, 24-hr peak flow 9.25 ft3/sec Pre/Post 1-yr, 24-hr peak flow control 6.62 ft3/sec Basin Elevations Basin bottom elevation 717.00 ft Sediment cleanout elevation 718.00 ft Bottom of shelf elevation 725.50 ft Permanent pool elevation 726.00 ft SHWT elevation 712.00 ft Top of shelf elevation 726.50 ft Temporary pool elevation 727.70 ft 1 Form SW401-Wet Detention Basin-Rev.4 Parts I.8 II. Design Summary, Page 1 of 2 Permit No. (to be provided by DWQ) IL DESIGN INFORMATION Volume and Surface Area Calculations SA/DA ratio 4.00 (unitless) Surface area at the bottom of shelf 11,462.00 e Volume at the bottom of shelf 52,187.00 ft3 Permanent pool, surface area required 12,458.00 ft Permanent pool, surface area provided 14,257.00 ftz OK Permanent pool volume 58,619.00 ft3 Average depth for SA/DA tables 4.11 ft OK Surface area at the top of shelf 17,373.00 ftz Volume at the top of shelf 66,405.00 ft3 Forebay volume 10,977.00 ft3 Forebay % of permanent pool volume 18.73 % OK Temporary pool, surface area provided 19,373.00 ft2 Drawdown Calculations Treatment volume drawdown time 3.30 days OK Treatment volume discharge rate 0.10 ff3/s Pre-development 1-yr, 24-hr discharge 2.63 ft3/s OK Post-development 1-yr, 24-hr discharge 1.76 ft3/s OK Additional Information Diameter of orifice 2.3 in Design TSS removal 90 % Basin side slopes 3.00 :1 OK Vegetated shelf slope 10.00 :1 OK Vegetated shelf width 10.00 It OK Length of flowpath to width ratio 4.40 :1 OK Length to width ratio 3.30 :1 OK Trash rack for overflow & orifice? Y (Y or N) OK Freeboard provided 2.25 It OK Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal Recorded drainage easement provided? Y (Y or N) OK Capures all runoff at ultimate build-out? Y (Y or N) OK Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP I Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2 Permit N (to be provided by DWQ) Ill. REQUIRED ITEMS CHECKLIST Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach justification. Pagel Plan Initials Sheet No. IMF C-3 1. Plans (1" - 50' or larger) of the entire site showing: - Design at ultimate build-out, - Off-site drainage (if applicable), ' - Delineated drainage basins (include Rational C coefficient per basin), - Basin dimensions, - Pretreatment system, ' - High flow bypass system, Maintenance access, - Proposed drainage easement and public right of way (ROVE, ' - Overflow device, and - Boundaries of drainage easement. K C4 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing: ' - Outlet structure with trash rack or similar, - Maintenance access, - Permanent pool dimensions, ' - Forebay and main pond with hardened emergency spillway, - Basin cross-section, - Vegetation specification for planting shelf, and - Filter strip. ' 13XK _C-7_ 3. Section view of the dry detention basin (1" = 20' or larger) showing: - Side slopes, 3:1 or lower, - Pretreatment and treatment areas, and ' - Inlet and outlet structures. _C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified on the plans prior to use as a wet detention basin. _C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay, to verify volume provided. ' g?c Attached 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the entire drainage area is stabilized. ' _Calc book- 7. The supporting calculations. -Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. -Attached- 9. A copy of the deed restrictions (if required). -Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County soil maps are not an acceptable source of soils information. Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1 Permit No. (to be provided by DWQ) AT"tA WDENR 1 1 1 1 1 1 1 1 1 1 1 1 1 O?o? W ATF9OG o STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WET DETENTION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information. I. PROJECT INFORMATION Project name Belgate Southern Tract Contact person Beverly Rosenbloom, El Phone number 704-319-7699 Date 3131/2009 Drainage area number 2 II. DESIGN' INFORMATION Site Characteristics Drainage area 1,093,791.60 ft2 Impervious area 807,166.80 ft2 % impervious 73.80 % Design rainfall depth 1.00 in Storage Volume: Non-SR Waters Minimum volume required 65,095.00 ft3 Volume provided 67,468.00 ft3 Storage Volume: SR Waters 1-yr, 24-hr runoff depth in Pre-development 1-yr, 24-hr runoff ft3 Post-development 1-yr, 24-hr runoff ft3 Minimum volume required fts Volume provided ft3 Peak Flow Calculations 1-yr, 24-hr rainfall depth 2.58 in Rational C, pre-development 0.28 (unitless) Rational C, post-development 0.79 (unitless) Rainfall intensity: )-yr, 24-hr storm 0.12 in/hr Pre-development 1-yr, 24-hr peak flow 1.57 ft3/sec Post-development 1-yr, 24-hr peak flow 24.36 ft3/SeC Pre/Post 1-yr, 24-hr peak flow control 22.79 ft3/sec Basin Elevations Basin bottom elevation 711.00 ft Sediment cleanout elevation 712.00 ft Bottom of shelf elevation 718.50 ft Permanent pool elevation 719.00 ft SHWT elevation 708.00 ft Top of shelf elevation 719.50 ft Temporary pool elevation 720.60 ft Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2 Permit No. (to be provided by DWQ) !L DESIGN INFORMATION Volume and Surface Area Calculations SAIDA ratio 3.38 (unitless) Surface area at the bottom of shelf 33,899.00 ft2 Volume at the bottom of shelf 163,941.00 ft3 Permanent pool, surface area required 35,872.00 ftz Permanent pool, surface area provided 38,235.00 ft2 OK Permanent pool volume 181,976.00 ft3 Average depth for SAIDA tables 4.76 ft OK Surface area at the top of shelf 42,920.00 ft2 Volume at the top of shelf 202,265.00 ft3 Forebay volume 33,586.00 ft3 Forebay % of permanent pool volume 18.46 % OK Temporary pool, surface area provided 46,100.00 ft2 Drawdown Calculations Treatment volume drawdown time 5.00 days OK Treatment volume discharge rate 0.16 ft3/s Pre-development 1-yr, 24-hr discharge 1.57 ft3/s OK Post-development 1-yr, 24-hr discharge 1.51 ft3/s OK Additional Information Diameter of orifice 2.9 in Design TSS removal 90 % Basin side slopes 3.00 :1 OK Vegetated shelf slope 10.00 :1 OK Vegetated shelf width 10.00 ft OK Length of flowpath to width ratio 4.10 :1 OK Length to width ratio 3.20 :1 OK Trash rack for overflow & orifice? Y (Y or N) OK Freeboard provided 2.65 ft OK Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal Recorded drainage easement provided? Y (Y or N) OK Capures all runoff at ultimate build-out? Y (Y or N) OK Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2 ' Permit No. (to be provided by DWQ) 111. REQUIRED ITEMS CHECKLIST ' Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach justification. Pagel Plan Initials Sheet No. _C-3_ 1. Plans (1" - 50' or larger) of the entire site showing: - Design at ultimate build-out, ' - Off-site drainage (if applicable), - Delineated drainage basins (include Rational C coefficient per basin), - Basin dimensions, - Pretreatment system, - High flow bypass system, - Maintenance access, - Proposed drainage easement and public right of way (ROW), - Overflow device, and - Boundaries of drainage easement. _C4 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing: Outlet structure with trash rack or similar, - Maintenance access, - Permanent pool dimensions, - Forebay and main pond with hardened emergency spillway, - Basin cross-section, - Vegetation specification for planting shelf, and - Filter strip. K? _C-7_ 3. Section view of the dry detention basin (1" = 20' or larger) showing: - Side slopes, 3:1 or lower, - Pretreatment and treatment areas, and - Inlet and outlet structures. _C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified ' on the plans prior to use as a wet detention basin. _ _C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay, A'tV" t 1_ to verify volume provided. 1 r s°t"" 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the entire drainage area is stabilized. _Calc book- 7. The supporting calculations. 441? -Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. -Attached- 9. A copy of the deed restrictions (if required). -Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County soil maps are not an acceptable source of soils information. 1 Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1 CURVE NUMBER CALCULATIONS STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina I \ Khnley-Hom I , I , and Associates, Inc. Pre vs. Post Runoff Analysis Composite Curve Number (CN) Project Information Project Name: Belgate - South Tract KHA Project #: 018253029 Designed by: BRR Revised by: BRR Revised by: Date: 10/6/2008 Date: 11/14/2008 Date: Drainage Area Name Drainage Location Cover/Soil Name (Type) Cover Description` Hydrologic Soil Group Curve # (CN)" Area (ac) Product of CN x area Composite Curve Number (CN) PRE-DEVELOPMENT DA-1 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 5.04 353 70 Meadow Good Condition B 71 5.04 358 71 i 10.08 1 711 70.5 , DA-2 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 2.95 207 70 Mecklenburg, Enon, Wilkes Meadow Good Condition C 71 2.95 209 71 Cecil Meadow Good Condition B 58 10.69 620 58 Cecil Woods Good Condition B 55 10.69 588 55 27.28 1624 59.5 Total Pre-development Area = 37.36 POST DEVELOPMENT DA-1 POND 1 Impervious 98 6.43 631 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition (from City Blvd) j C 73 0.29 21 73 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 0.71 53 74 7.44 704.63 1 94.72 UND DA-1 Mecklenburg, OUTFALL 1 Enon, Wilkes Open Space - Good Condition C 74 0.90 67 74 0.90 ! 66.60 74.00 DA-2 POND 2 Impervious ! 98 15.40 1509 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition I i C 74 0.83 61 74 Cecil Open Space - Good Condition B 61 4.11 251 61 Roadway - Impervious 98 3.13 307 96 Mecklenburg, En n. Wilkes Roadway - Open Space C 74 1.54 114 74 Cecil Roadway - Open Space B 61 0.10 6 61 25.11 1 2248.13 89.53 UND DA-2 OUTFALL 2 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 2.96 219 74 Cecil Open Space -Good Condition i g 61 2.97 j 181 61 5.93 400.21 1 67.49 Total Post-development Area = 39.38 ' Cover Descriptions per TR-55 Manual From TR-55 Manual, Table 2-2 a & c K:\CHL_LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Calculations\South Tract\Stormwater Calculations_2008-1 0-06.xls 1 of 1 TIME OF CONCENTRATION CALCULATIONS LAU61UIV CUNIROL CALCULATIONS New Towne Gardens, Union County, North Carolina ? f! E: i= c E m F > V N O C Q ; u C 7 ? m - m a v - m m ^ m m w a N Q m o? C O U LL (q O O V m m C D. ? N a W V O m Q N c N rn m C V 7 C L c m V 0 o 0 U ° d ? w £ w ? F L N a a 0 0 J t N O ? Q J O N O LL N d m t0 t0 N Q Q Q c n y 0 U ry U m OJ ? O d L _ ? O o !n ? ? LL O m t0 m m a m ~ ui 7t a. y;,, ?. a z m m m m d o a , N N Q U N y m m D ? =QQ: lY ? 7 C O d Y LL A CC p C L d LL E LL m C Z O LL 6 m N 0 0 O H N 1'1? M 0 V A Q o o a f ? II C E ? m M h C E F C m C ` o C m C U o < o 2 C m m C U `o co n I N ? P ? C] M I 1 ? M I I I I of I di I a O or i col O of fofpp O c ? O o ?? OI of o, O o 00 O fD O m N lh o o o o U 3 Z c .d 00 a o m U 3` Z ? ? y t0 a d C d a ? ? C N N p U L U y N U U L U Q J N Q J J ? O J F O Q N O I A C 1 E n CJ F c r d ? U o C _c E I ~ i I N M I I? 0+ I i OI it c i O. O O G O C I m as v°o °o o °o o U Z W o _N N C C O N c ? U U N O w° ? a c \ LL C ad G m 0 U O n L N ? o '^ mm N d ` IY ~ LL ~ n - c c o ? O may ? U N N h p F c ? L Q O LL U LL U 0 HYDROCAD HYDROLOGY REPORT WET DETENTION POND I ' EROSION CONTROL CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina 1S Pre-dev DA-1 2S 45 Post-de DA-1 Post-dev ND DA-1 3P' 8P South Tract Wet Pond 1 Outfall 1 Subca Each on Link. Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paoe 2 Summary for Subcatchment 1S: Pre-dev DA-1 Runoff = 4.17 cfs @ 12.23 hrs, Volume= 0.442 af, Depth> 0.53" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 10.080 71 10.080 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 25.2 Direct Entry, From spreadsheet Subcatchment 1S: Pre-dev DA-1 Hydrograph Runoff w v 3 0 U- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 2S: Post-dev DA-1 ' Runoff = 25.35 cfs @ 11.95 hrs, Volume= 1.264 af, Depth> 2.04" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 7.440 95 7.440 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, From spreadsheet Subcatchment 2S: Post-dev DA-1 Hydrograph Runoff 3 0 LL U i L 3 a o e i s 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=258" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 4S: Post-dev UND DA-1 Runoff = 1.01 cfs @ 11.97 hrs, Volume= 0.049 af, Depth> 0.65" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 0.900 74 0.900 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, w 0 LL Subcatchment 4S: Post-dev UND DA-1 Hydrograph 1 cfs 1.0 ..:.... ....... --- ---- --- -- ...- - -------------- CharJotte' 24-hr 1-yr 1 yr - 24 hr Rainfall=2.68" :Runoff Area=0.900 ac btu off'VolU e=:0.049 of Runoff `D6Pth>0.05, tc=5. min GN=74 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ® Runoff Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfal1=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5 Summary for Pond 3P: South Tract Wet Pond 1 Inflow Area = 7.440 ac, 0.00% Impervious, Inflow Depth > 2.04" for 1 yr - 24 hr event Inflow = 25.35 cfs @ 11.95 hrs, Volume= 1.264 of Outflow = 1.23 cfs @ 12.97 hrs, Volume= 0.555 af, Atten= 95%, Lag= 61.2 min Primary = 1.23 cfs @ 12.97 hrs, Volume= 0.555 of Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 728.00' @ 12.97 hrs Surf.Area= 19,939 sf Storage= 35,291 cf Plug-Flow detention time= 301.2 min calculated for 0.555 of (44% of inflow) Center-of-Mass det. time= 181.3 min ( 964.5 - 783.2 ) Volume Invert Avail.Storage Storage Description #1 726.00' 130,637 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 726.00 14,257 0 0 727.00 18,100 16,179 16,179 728.00 19,930 19,015 35,194 729.00 21,832 20,881 56,075 730.00 23,807 22,820 78,894 731.00 25,853 24,830 103,724 732.00 27,972 26,913 130,637 Device Routing Invert Outlet Devices #1 Primary 726.00' 24.0" x 51.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 725.00' S=0.0196/' Cc= 0.900 n=0.013 #2 Device 1 726.00' 2.3" Vert. Orifice/Grate C= 0.600 #3 Device 1 727.75' 2.50' W x 1.00'H Vert. Orifice/Grate C=0.600 #4 Secondary 730.50' 15.0' long x 13.5' breadth Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.62 2.66 2.70 2.66 2.65 2.66 2.65 2.63 #5 Device 1 729.50' 14.0' long x 0.5' breadth Grate on Overflow Structure Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=1.22 cfs @ 12.97 hrs HW=728.00' (Free Discharge) t1=Culvert (Passes 1.22 cfs of 15.16 cfs potential flow) U-==Grate Orifice/Grate (Orifice Controls 0.19 cfs @ 6.65 fps) Orifice/Grate (Orifice Controls 1.03 cfs @ 1.62 fps) on Overflow Structure ( Controls 0.00 cfs) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=726.00' (Free Discharge) L4=Emergency Spillway (Controls 0.00 cfs) Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 6 Pond 3P: South Tract Wet Pond 1 Hydrograph d u ® Inflow ' r-M Outflow Primary 12 Secondary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 ZO 21 ZZ Zs Z4 Time (hours) Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 7 Stage-Discharge for Pond 3P: South Tract Wet Pond 1 Elevation Discharge Primary Secondary (feet) (cfs) (cfs) (cfs) 726.00 0.00 0.00 0.00 726.10 0.02 0.02 0.00 726.20 0.04 0.04 0.00 726.30 0.06 0.06 0.00 726.40 0.08 0.08 0.00 726.50 0.09 0.09 0.00 726.60 0.10 0.10 0.00 726.70 0.11 0.11 0.00 726.80 0.12 0.12 0.00 726.90 0.12 0.12 0.00 727.00 0.13 0.13 0.00 727.10 0.14 0.14 0.00 727.20 0.15 0.15 0.00 727.30 0.15 0.15 0.00 727.40 0.16 0.16 0.00 727.50 0.16 0.16 0.00 727.60 0.17 0.17 0.00 727.70 0.18 0.18 0.00 727.80 0.27 0.27 0.00 727.90 0.65 0.65 0.00 728.00 1.19 1.19 0.00 728.10 1.86 1.86 0.00 728.20 2.62 2.62 0.00 728.30 3.48 3.48 0.00 728.40 4.42 4.42 0.00 728.50 5.43 5.43 0.00 728.60 6.51 6.51 0.00 728.70 7.65 7.65 0.00 728.80 8.77 8.77 0.00 728.90 9.66 9.66 0.00 729.00 10.45 10.45 0.00 729.10 11.17 11.17 0.00 729.20 11.83 11.83 0.00 729.30 12.46 12.46 0.00 729.40 13.06 13.06 0.00 729.50 13.62 13.62 0.00 729.60 15.40 15.40 0.00 729.70 18.19 18.19 0.00 729.80 21.77 21.77 0.00 729.90 25.76 25.76 0.00 730.00 26.20 26.20 0.00 730.10 26.63 26.63 0.00 730.20 27.06 27.06 0.00 730.30 27.48 27.48 0.00 730.40 27.89 27.89 0.00 730.50 28.30 28.30 0.00 730.60 29.94 28.70 1.24 730.70 32.61 29.10 3.52 730.80 35.99 29.49 6.51 730.90 39.97 29.87 10.09 731.00 44.47 30.25 14.21 731.10 49.45 30.63 18.82 731.20 54.54 31.00 23.54 731.30 59.92 31.37 28.55 Elevation Discharge Primary Secondary (feet) (cfs) (cfs) (cfs) 731.40 65.73 31.73 34.00 731.50 71.84 32.09 39.75 731.60 78.39 32.44 45.95 731.70 85.24 32.79 52.45 731.80 92.17 33.14 59.03 731.90 99.33 33.48 65.85 732.00 106.57 33.82 72.75 Southern Tract Pond 1 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" ' Prepared by Kimley-Horn and Associates, Inc. Printed 6/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 8 ' Summary for Pond 8P: Outfall 1 Inflow Area = 8.340 ac, 0.00% Impervious, Inflow Depth > 0.87" for 1 yr - 24 hr event ' Inflow = 1.30 cfs @ 12.93 hrs, Volume= 0.604 of Primary = 1.30 cfs @ 12.93 hrs, Volume= 0.604 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Pond 8P: Outfall 1 Hydrograph Inflow FE-1 n fi- Primary , N w V 3 O U. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) HYDROCAD HYDROLOGY REPORT WET DETENTION POND 2 EROSION CONTROL CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina (5S (6S) (8S) Pre-dev DA-2 Post-d v DA-2 Post-dev ND DA-2 7P -? 9P South Tract Wet Pond 2 Outfall 2 Subca Reach on link Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 5S: Pre-dev DA-2 Runoff = 1.46 cfs @ 12.62 hrs, Volume= 0.435 af, Depth> 0.19" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 27.280 60 27.280 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 41.7 Direct Entry, From Spreadsheet Subcatchment 5S: Pre-dev DA-2 Hydrograph Runoff w 3 0 U. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr- 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 6S: Post-dev DA -2 Runoff = 71.04 cfs @ 11.96 hrs, Volume= 3.351 af, Depth> 1.60" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 25.110 90 25.110 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 6S: Post-dev DA-2 Hydrograph -- -------------------- 7 - -- r --- - ----- - - - Runoff 75 71.04 cfs .. 70 ' _........ - ; ....: .... -... Ghar1otte 24-hr.... 65 --------------- - --------- --------------- - - - - - 1--y ?t r :24--hr---- 60 ------- ------------------------ ---------------- 55 ' Raltlf«-2 r$? 50 R??r?nff Ards-7? 77nw7?,. Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 4 Summary for Subcatchment 8S: Post-dev UND DA-2 Runoff = 1.07 cfs @ 12.49 hrs, Volume= 0.189 af, Depth> 0.38" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 5.930 67 5.930 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 41.7 Direct Entry, Subcatchment 8S: Post-dev UND DA-2 Hydrograph ® Runoff I w 0 3 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southern Tract Pond 2 Charlotte 24-hr 7 yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCAD0 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5 Summary for Pond 7P: South Tract Wet Pond 2 Inflow Area = 25.110 ac, 0.00% Impervious, Inflow Depth > 1.60" for 1 yr - 24 hr event Inflow = 71.04 cfs @ 11.96 hrs, Volume= 3.351 of Outflow = 0.37 cfs @ 24.00 hrs, Volume= 0.361 af, Atten= 99%, Lag= 722.7 min Primary = 0.37 cfs @ 24.00 hrs, Volume= 0.361 of Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 721.89'@ 24.00 hrs Surf.Area= 50,086 sf Storage= 130,204 cf Plug-Flow detention time= 439.9 min calculated for 0.360 of (11 % of inflow) Center-of-Mass det. time= 263.1 min ( 1,074.0 - 811.0 ) Volume Invert Avail.Storage Storage Description #1 719.00' 301,703 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 719.00 38,235 0 0 720.00 44,277 41,256 41,256 721.00 47,329 45,803 87,059 722.00 50,442 48,886 135,945 723.00 53,616 52,029 187,974 724.00 56,850 55,233 243,207 725.00 60,143 58,497 301,703 Device Routing Invert Outlet Devices #1 Primary 719.00' 24.0" x 147.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 716.00' S= 0.0204'/' Cc= 0.900 n=0.013 #2 Device 1 719.00' 2.9" Vert. Orifice/Grate C= 0.600 #3 Device 1 722.00' 1.50' W x 0.50'H Vert. Orifice/Grate C=0.600 #4 Secondary 723.50' 40.0' long x 13.5' breadth Emergency Spillway Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.62 2.66 2.70 2.66 2.65 2.66 2.65 2.63 #5 Device 1 723.60' 14.0' long x 0.5' breadth Grate on Overflow Structure Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32 Primary OutFlow Max=0.37 cfs @ 24.00 hrs HW=721.89' (Free Discharge) L1=Culvert (Passes 0.37 cfs of 20.77 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.37 cfs @ 8.01 fps) 3=Orifice/Grate ( Controls 0.00 cfs) -Grate on Overflow Structure ( Controls 0.00 cfs) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=719.00' (Free Discharge) t4=Emergency Spillway (Controls 0.00 cfs) Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 6 Pond 7P: South Tract Wet Pond 2 Hydrograph u M 3 c u ¦ Inflow ' Outflow i Primary ' Secondary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Z1 ZZ Z6 24 Time (hours) Southern Tract Pond 2 Charlotte 24-hr 1-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 7 Stage-Discharge for Pond 7P: South Tract Wet Pond 2 Elevation Discharge Primary Secondary (feet) (cfs) (cfs) (cfs) 719.00 0.00 0.00 0.00 719.10 0.02 0.02 0.00 719.20 0.06 0.06 0.00 719.30 0.09 0.09 0.00 719.40 0.12 0.12 0.00 719.50 0.14 0.14 0.00 719.60 0.15 0.15 0.00 719.70 0.17 0.17 0.00 719.80 0.18 0.18 0.00 719.90 0.19 0.19 0.00 720.00 0.21 0.21 0.00 720.10 0.22 0.22 0.00 720.20 0.23 0.23 0.00 720.30 0.24 0.24 0.00 720.40 0.25 0.25 0.00 720.50 0.26 0.26 0.00 720.60 0.27 0.27 0.00 720.70 0.28 0.28 0.00 720.80 0.29 0.29 0.00 720.90 0.29 0.29 0.00 721.00 0.30 0.30 0.00 721.10 0.31 0.31 0.00 721.20 0.32 0.32 0.00 721.30 0.33 0.33 0.00 721.40 0.33 0.33 0.00 721.50 0.34 0.34 0.00 721.60 0.35 0.35 0.00 721.70 0.35 0.35 0.00 721.80 0.36 0.36 0.00 721.90 0.37 0.37 0.00 722.00 0.37 0.37 0.00 722.10 0.53 0.53 0.00 722.20 0.82 0.82 0.00 722.30 1.18 1.18 0.00 722.40 1.62 1.62 0.00 722.50 2.11 2.11 0.00 722.60 2.50 2.50 0.00 722.70 2.81 2.81 0.00 722.80 3.08 3.08 0.00 722.90 3.32 3.32 0.00 723.00 3.55 3.55 0.00 723.10 3.76 3.76 0.00 723.20 3.96 3.96 0.00 723.30 4.14 4.14 0.00 723.40 4.32 4.32 0.00 723.50 4.49 4.49 0.00 723.60 7.97 4.66 3.31 723.70 15.43 6.06 9.37 723.80 25.83 8.47 17.35 723.90 38.61 11.70 26.92 724.00 53.50 15.60 37.90 724.10 70.44 20.25 50.19 724.20 88.36 25.58 62.78 724.30 107.50 31.37 76.13 Elevation Discharge Primary Secondary (feet) (cfs) (cfs) (cfs) 724.40 122.41 31.73 90.68 724.50 138.09 32.09 106.00 724.60 154.96 32.44 122.52 724.70 172.66 32.79 139.87 724.80 190.55 33.14 157.41 724.90 209.07 33.48 175.59 725.00 227.82 33.82 194.00 Southern Tract Pond 2 Charlotte 24-hr 9-yr 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 4/24/2009 HydroCADO 8 50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 8 Summary for Pond 9P: Outfall 2 Inflow Area = 31.040 ac, 0.00% Impervious, Inflow Depth > 0.21" for 1 yr - 24 hr event Inflow = 1.37 cfs @ 12.50 hrs, Volume= 0.550 of Primary = 1.37 cfs @ 12.50 hrs, Volume= 0.550 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Pond 9P: OutFall 2 Hydrograph ¦ Inflow ® Primary H w V 3 O U. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 16 1U 1u L1 LL t.5 cw Time (hours)