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HomeMy WebLinkAboutSW3221201_Design Calculations_20221206STORM DRAINAGE, EROSION CONTROL, & WATER QUALITY CALCULATIONS FOR CAROLINA PETS ANIMAL HOSPITAL Waxhaw-Indian Trail Rd, Wesley Chapel, NC 28014 Carolina Pets Animal Hospital 5922 Weddington Rd Wesley Chapel, NC 28104 Date: 11 /03/2020 Revised: 12/21/2021 URBAN DESIGN PARTNERS "1801- 1213 West Morehead St. Suite 450 Charlotte, NC 28208 NCBELS Firm #: P-0418 SC COA #: C-03044 Project No: 19-CLT-027 Calculations By: EDP CA/3C� , �O •FESS/p�,/�j,, A L, 0 12.23.2021 NARRATIVE The following project, Carolina Pets Animal Hospital, is a 2.63-acre site consisting of a commercial building, parking, and a sand filter BMP. The pre development conditions include 3 drainage areas consisting of 11 acres converging into two points of interest located just west of the site. The post development conditions include 4 drainage areas consisting of 11 acres converging into two points of interest located just west of the site. The two points of interest were used to determine that the post conditions meet all town of Wesley Chapel stormwater requirements as found in the following report. A summary of the pre and post flows for the two points of interest can be found on the following page. Drainage area delineations can be found on the plan sheet C-5.4. Page 2 of 140 Carolina Pets Pre vs Post Development Flows DATE: 12/22/21 Pre Development Area ac 1 year 24 hr flo 12 year 24 hr flo 110 year 24 hr flow cfs 25 year 24 hr flow (cfs) POI #1 6.50 3.95 6.561 20.69 POI #2 4.5 0.7611 1.68111 7.90 *Total 11.00 4.4111 7.73 19.06 1 27.08 *Total determined from peak flow of combined DAs at maximum Q (See hydrograph tables) Post Development Area ac 1 year 24 hr flo 12 year 24 hr flo 110 year 24 hr flow cfs 25 year 24 hr flow (cfs) POI #1 5.27 3.311111 15.62 POI #2 5.73 1.3411 2.68111 11.3 *Total 11.00 4.6511 7.63111 26.92 *Total determined from peak flow of combined DAs at maximum Q (See hydrograph tables) CALCULATIONS Page 4 of 140 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St Suite 450 DATE: 10/12/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 STORM DRAINAGE DESIGN DATA LOCATION FROM TO DRAIN AREA (acres) RUNOFF C I Q inlet Q pipe (cfs) (cfs) PIPE ROUNDED n SLOPE LENGTH SIZE SIZE (%) (ft) (inches) (inches) FULL ACTUAL VEL. CAPACITY VEL. (fps) (cfs) (fps) INVERT ELEV. INV INV INV OUT IN OUT PIPE DEPTH (FROM) (FROM) RIM COVER ELEVATION DEPTH YI-106 CI-105 0.16 0.20 7.26 0.2 0.2 0.013 0.74% 27 4.6 15 4.5 5.58 #N/A 636.20 636.00 639.80 2.10 CI-105 CI-104 0.15 0.95 7.26 1.0 1.3 0.013 0.51 % 97 9.2 18 4.3 7.55 2.90 636.00 635.50 639.86 2.07 CI-104 JB-103 0.35 0.95 7.26 2.4 4.3 0.013 0.53916 76 14.5 18 4.3 7.65 4.46 635.50 635.10 640.30 3.01 JB-103 DI-102 0.00 0.95 7.26 0.0 4.3 0.013 1.76% 63 11.6 18 7.9 13.97 6.72 635.10 634.00 639.69 2.80 DI-102 JB-101 0.21 0.95 7.26 1.4 5.7 0.013 0.62% 64 15.7 24 5.7 17.90 4.84 633.80 633.40 637.65 1.54 JB-101 FES-100 0.00 0.95 7.26 0.0 5.7 0.013 2.41 % 33 12.2 24 11.2 35.24 7.63 633.40 632.60 637.88 2.17 OCS HW Outlet 0.95 7.26 0.0 3.0 0.013 1.25916 36 10.8 18 6.7 11.78 5.40 628.60 628.15 CI-107 CI-104 0.09 0.95 7.26 0.6 0.6 0.013 2.50% 60 5.2 18 9.4 16.65 4.33 637.00 635.50 641.77 2.98 BYPASS rO8 DI-110 DI-109 0.12 7.26 0.7 0.7 0.013 2.39% 189 5.7 15 8.2 10.01 3.75 640.00 635.50 646.33 4.83 DI-109 EXIST. DROP INLET 0.65 0.85 1 7.26 4.0 4.0 0.013 1.03% 1 58 12.5 15�j 5.3 1 6.56 5.67 11 635.30 634.70 639.68 2.88 FES-100 - 5.7 CFS 300 Outlet W . D0 + La pipe I diameter (Do) La —� ilwater 0.530 c ok � so VaOr 1 X 0.5 - FES-100 0 5 1': 20 50 100 200 500 1000 Discharge(Olsec) Curves may not be extrapolated. Figure 8.06a DOSign of outlet protection protection from a round pipe flowing full, minimum tailwater condition {Tw < 0-5 dameter). Rev. 1_ 9; S.06.? RI P-RAP ,APRON DE S IG H GALCU LATISH S OUTLET jDischargj (cfs} Do(in} d50 I La(ft} 11=Do-j W1(ft} W2=3*Do W2{ft} *T(ft) �H=Qf3rDo H{ft} FES-100 24 15 B 1,125 1,33 dmax = 1. 5 "d50 T=1,5''dmax (Min. T=10") Min. to=10rt HW Outlet - 3.03 CFS 300 Outlet W . D0 + La pipe I diameter (Do) La —� ilwater 0.500 ok � so VaOr 1 X m 2 U) a m n 0 1 0.5 - FES-100 0 3 5 1': 20 50 100 200 500 1000 Discharge(Olsec) Curves may not be extrapolated. Figure 8.06a Dosign of outlet protection protection from a round pipe flowing full, minimum tailwater condition {Tw < 0-5 dameter). Rev. 12 93 S.06,? RIP -RAP APRON DESIGN CALCULATIONS OUTLET Discharg i;cfs} I Win} d50 I I La{ft} I 1=Do+ 1W1jit)j W2=3':D0 W2{ft} kT(ft) H= 22rDo Hit} HWoudet 103 0.5 10 11,.E 4.5 1,125 1.00 armax = 1,51d50 T=1.5"dmax (Min. T=10") Min, La=?Ott 25-YEAR HGL CALCULATIONS Page 6 of 140 Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan Project File: Storm Sewer HGLs.stm 4 5 3 g 2 1 Outfall Outfall Number of lines: 9 1 Date: 8/11/2021 ,rorm ,ewers vzuzu.w Hydraulic Grade Line Computations Page 1 Line Size Q Downstream Len Upstream Check JL Minor coeff loss Invert HGL Depth Area Vel Vel EGL Sf Invert HGL Depth Area Vel Vel EGL Sf Ave Enrgy elev elev head elev elev elev head elev Sf loss (in) (cfs) (ft) (ft) (ft) (sqft) (ft/s) (ft) (ft) (%) (ft) (ft) (ft) (ft) (sgft) (ft/s) (ft) (ft) (%} (%) (ft) (K) (ft) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) 1 18 6.50 632.60 633.59 0.99 1.23 5.28 0.43 634.02 0.000 34.079 633.40 634.39 0.99** 1.23 5.28 0.43 634.82 0.000 0.000 n/a 0.78 0.34 2 18 6.50 633.40 634.39 0.99* 1.23 5.28 0.43 634.82 0.000 50.254 633.80 634.79 0.99** 1.23 5.28 0.43 635.22 0.000 0.000 n/a 0.99 0.43 3 18 5.10 634.00 634.79 0.79 0.94 5.45 0.36 635.14 0.000 62.566 635.10 635.97 0.87** 1.06 4.81 0.36 636.33 0.000 0.000 n/a 1.00 0.36 4 18 5.10 635.10 636.00 0.90* 1.10 4.62 0.33 636.33 0.527 75.852 635.50 636.40 0.90 1.10 4.62 0.33 636.73 0.526 0.526 0.399 1.00 0.33 5 18 2.10 635.50 636.73 1.23 0.58 1.35 0.20 636.93 0.000 97.335 636.00 636.55 0.55** 0.58 3.61 0.20 636.75 0.000 0.000 n/a 0.64 0.13 6 18 1.00 636.00 636.55 0.55 0.34 1.72 0.13 636.68 0.000 26.984 636.20 636.57 j 0.37** 0.34 2.92 0.13 636.71 0.000 0.000 n/a 1.00 0.13 7 18 0.60 635.50 636.73 1.23 0.24 0.39 0.10 636.83 0.000 60.018 637.00 637.29 j 0.29** 0.24 2.54 0.10 637.39 0.000 0.000 n/a 1.00 0.10 8 15 4.70 634.70 635.48 0.78* 0.81 5.80 0.40 635.89 0.000 58.453 635.30 636.18 0.88** 0.92 5.10 0.40 636.58 0.000 0.000 n/a 0.15 0.06 9 15 0.70 635.50 636.18 0.68 0.26 1.03 0.12 636.29 0.000 188.47 1640.00 640.33 j 0.33** 0.26 2.74 0.12 640.44 0.000 0.000 n/a 1.00 n/a Project File: Storm Sewer HGLs.stm Number of lines: 9 Run Date: 8/11/2021 Notes: * depth assumed; ** Critical depth.; j-Line contains hyd. jump c = cir e = ellip b = box Storm Sewers v202O.00 Hydraflow HGL Computation Procedure Page 1 General Procedure: Hydraflow computes the HGL using the Bernoulli energy equation. Manning's equation is used to determine energy losses due to pipe friction. In a standard step, iterative procedure, Hydraflow assumes upstream HGLs until the energy equation balances. If the energy equation cannot balance, supercritical flow exists and critical depth is temporarily assumed at the upstream end. A supercritical flow Profile is then computed using the same procedure in a downstream direction using momentum principles. Col. 1 The line number being computed. Calculations begin at Line 1 and proceed upstream. Col. 2 The line size. In the case of non -circular pipes, the line rise is printed above the span. Col. 3 Total flow rate in the line. Col. 4 The elevation of the downstream invert. Col. 5 Elevation of the hydraulic grade line at the downstream end. This is computed as the upstream HGL + Minor loss of this line's downstream line. Col. 6 The downstream depth of flow inside the pipe (HGL - Invert elevation) but not greater than the line size. Col. 7 Cross -sectional area of the flow at the downstream end. Col. 8 The velocity of the flow at the downstream end, (Col. 3 / Col. 7). Col. 9 Velocity head (Velocity squared / 2g). Col. 10 The elevation of the energy grade line at the downstream end, HGL + Velocity head, (Col. 5 + Col. 9). Col. 11 The friction slope at the downstream end (the S or Slope term in Manning's equation). Col. 12 The line length. Col. 13 The elevation of the upstream invert. Col. 14 Elevation of the hydraulic grade line at the upstream end. Col. 15 The upstream depth of flow inside the pipe (HGL - Invert elevation) but not greater than the line size. Col. 16 Cross -sectional area of the flow at the upstream end. Col. 17 The velocity of the flow at the upstream end, (Col. 3 / Col. 16). Col. 18 Velocity head (Velocity squared / 2g). Col. 19 The elevation of the energy grade line at the upstream end, HGL + Velocity head, (Col. 14 + Col. 18) . Col. 20 The friction slope at the upstream end (the S or Slope term in Manning's equation). Col. 21 The average of the downstream and upstream friction slopes. Col. 22 Energy loss. Average Sf/100 x Line Length (Col. 21/100 x Col. 12). Equals (EGL upstream - EGL downstream) +/- tolerance. Col. 23 The junction loss coefficient (K). Col. 24 Minor loss. (Col. 23 x Col. 18). Is added to upstream HGL and used as the starting HGL for the next upstream line(s). Page 9 of 140 Storm Sewer Profile Proj. file: Storm Sewer HGLs.stm Elev. (ft) 654.00 649.00 644.00 639.00 634.00 629.00 0 r Cn C � J (] C 7 . . ■MI■IM ■IM�EMININMEF00- I M-Wit i 25 50 75 HGL EGL RoIe] 649.00 644.00 639.00 634.00 629.00 100 125 150 175 200 225 250 275 300 Reach (ft) Page 10 of 140 Storm Sewers Storm Sewer Profile Proj. file: Storm Sewer HGLs.stm Elev. (ft) 648.00 645.00 642.00 639.00 636.00 633.00 0 645.00 642.00 639.00 636.00 ----------- 633.00 10 20 30 40 50 60 70 80 90 100 110 120 130 HGL EGL Reach (ft) Page 11 of 140 Storm Sewers Storm Sewer Profile Proj. file: Storm Sewer HGLs.stm Elev. (ft) 656.00 651.00 M c CO 4 c c Q 656.00 651.00 646.00 646.00 641.00 636.00 631.00 641.00 '636.00 631.00 0 25 50 75 100 125 150 175 200 225 250 HGL EGL Reach (ft) Page 12 of 140 ---------- ---------- Storm Sewers DITCH CALCULTIONS Page 13 of 140 NORTH AMERICAN GREEN CHANNEL ANALYSIS > > > Temporary Diversion Ditch 1 Name Temporary Diversion Ditch 1 Discharge 2.89 Channel Slope 0.016 Channel Bottom Width 2 Left Side Slope 3 Right Side Slope 3 Low Flow Liner Retardence Class C 6-12 in Vegetation Type Bunch Type Vegetation Density None Soil Type Clay Loam (CL) DS75 North American Green 5401 St. Wendel -Cynthiana Rd. Poseyville, Indiana 47633 Tel. 800.772.2040 > Fax 812.867.0247 www.nagreen.com ECMDS v7.0 Phase Reach Discharge Velocity Normal Mannings N Permissible Calculated Safety Remarks Staple Depth Shear Stress Shear Stress Factor Pattern DS75 Straight 2.89 cfs 2.27 ft/s 0.4 ft 0.035 1.6 Ibs/ft2 0.4 Ibs/ft2 4.03 STABLE D Unvegetated Underlying Straight 2.89 cfs 2.27 ft/s 0.4 ft 0.035 1.74 Ibs/ft2 0.28 Ibs/ft2 6.21 STABLE D Substrate Page 14 of 140 NORTH AMERICAN GREEN CHANNEL ANALYSIS > > > Temporary Diversion Ditch 2 Name Temporary Diversion Ditch 2 Discharge 13.23 Channel Slope 0.0016 Channel Bottom Width 2 Left Side Slope 3 Right Side Slope 3 Low Flow Liner Retardence Class C 6-12 in Vegetation Type Bunch Type Vegetation Density None Soil Type Clay Loam (CL) DS75 North American Green 5401 St. Wendel -Cynthiana Rd. Poseyville, Indiana 47633 Tel. 800.772.2040 > Fax 812.867.0247 www.nagreen.com ECMDS v7.0 Phase Reach Discharge Velocity Normal Mannings N Permissible Calculated Safety Remarks Staple Depth Shear Stress Shear Stress Factor Pattern DS75 Straight 13.23 cfs 1.3 ft/s 1.54 ft 0.041 1.6 Ibs/ft2 0.15 Ibs/ft2 10.43 STABLE D Unvegetated Underlying Straight 13.23 cfs 1.3 ft/s 1.54 ft 0.041 1.74 Ibs/ft2 0.09 Ibs/ft2 20.16 STABLE D Substrate Page 15 of 140 NORTH AMERICAN GREEN CHANNEL ANALYSIS > > > Temporary Diversion Ditch 3 Name Temporary Diversion Ditch 3 Discharge 8.1 Channel Slope 0.019 Channel Bottom Width 2 Left Side Slope 3 Right Side Slope 3 Existing Bend Radius 3 Low Flow Liner Retardence Class C 6-12 in Vegetation Type Bunch Type Vegetation Density None Soil Type Clay Loam (CL) P300 North American Green 5401 St. Wendel -Cynthiana Rd. Poseyville, Indiana 47633 Tel. 800.772.2040 > Fax 812.867.0247 www.nagreen.com ECMDS v7.0 Phase Reach Discharge Velocity Normal Mannings N Permissible Calculated Safety Remarks Staple Depth Shear Stress Shear Stress Factor Pattern P300 Straight 8.1 cfs 3.47 ft/s 0.61 ft 0.032 2.3 Ibs/ft2 0.72 Ibs/ft2 3.18 STABLE E Unvegetated Underlying Straight 8.1 cfs 3.47 ft/s 0.61 ft 0.032 2.51 Ibs/ft2 0.47 Ibs/ft2 5.3 STABLE E Substrate P300 Reinforced Straight 8.1 cfs 2.25 ft/s 0.81 ft 0.058 10 Ibs/ft2 0.96 Ibs/ft2 10.4 STABLE E Vegetation Underlying Straight 8.1 cfs 2.25 ft/s 0.81 ft 0.058 2.3 Ibs/ft2 0.6 Ibs/ft2 3.85 STABLE E Substrate P300 Bend 8.1 cfs 3.47 ft/s 0.61 ft 0.032 2.3 Ibs/ft2 1.45 Ibs/ft2 1.59 STABLE E Unvegetated Underlying Bend 8.1 cfs 3.47 ft/s 0.61 ft 0.032 2.51 Ibs/ft2 0.94 Ibs/ft2 2.65 STABLE E Substrate P300 Reinforced Bend 8.1 cfs 2.25 ft/s 0.81 ft 0.058 10 Ibs/ft2 1.92 Ibs/ft2 5.2 STABLE E Vegetation Underlying Bend 8.1 cfs 2.25 ft/s 0.81 ft 0.058 2.3 Ibs/ft2 1.2 Ibs/ft2 1.92 STABLE E Substrate Page 16 of 140 NORTH AMERICAN GREEN CHANNEL ANALYSIS > > > Permanent Bypass Ditch Name Permanent Bypass Ditch Discharge 9.23 Channel Slope 0.025 Channel Bottom Width 0 Left Side Slope 3 Right Side Slope 3 Low Flow Liner Retardence Class C 6-12 in Vegetation Type Bunch Type Vegetation Density None Soil Type Clay Loam (CL) P300 North American Green 5401 St. Wendel -Cynthiana Rd. Poseyville, Indiana 47633 Tel. 800.772.2040 > Fax 812.867.0247 www.nagreen.com ECMDS v7.0 Normal Permissible Calculated Safety Staple Phase Reach Discharge Velocity Mannings N Remarks Depth Shear Stress Shear Stress Factor Pattern P300 Straight 9.23 cfs 4.19 ft/s 0.86 ft 0.031 2.3 Ibs/ft2 1.34 Ibs/ft2 1.72 STABLE E Unvegetated Underlying Straight 9.23 cfs 4.19 ft/s 0.86 ft 0.031 2.51 Ibs/ft2 0.63 Ibs/ft2 3.95 STABLE E Substrate P300 Reinforced Straight 9.23 cfs 2.83 ft/s 1.04 ft 0.052 10 Ibs/ft2 1.63 Ibs/ft2 6.15 STABLE E Vegetation Underlying Straight 9.23 cfs 2.83 ft/s 1.04 ft 0.052 2.3 Ibs/ft2 0.77 Ibs/ft2 2.98 STABLE E Substrate Page 17 of 140 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 8/25/21 TIME OF CONCENTRATION WORKSHEET BYPASS DITCH DA SHEET FLOW Max. Elevation: 654.5 Min. Elevation: 652 Flow Length (ft): 150 Slope: 1.67% Mannings: 0.24 Table 2-13 SWDM Preci itation: 3.55 2- r, 24-hr rainfall Travel Time: 0.34 hr Eq. 2.9 SWDM SHALLOW CONCENTRATED Max. Elevation: 650.8 Min. Elevation: 646 Flow Length ft : 127 Slope: 3.78% Velocity (fps): 3.14 E . 2.15 SWDM Travel Time: 40.49 sec 0.011 hr CHANNEL FLOW Flow Length ft : 446 Velocity (fps): 4.11 "Per North American Green Matting Calculations: =Q/A Travel Time: 108.52 sec PI 0.030 hr TIME OF CONCENTRATION Total: 0.38 hr 23 min Page 18 of 140 Page 1 of 1 Carolina Pets Urban Design Partners JOB NO.: 19-160 BY: UDP 1213 W Morehead St ste 450 DATE: 8/28/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 8/25/211 Ditch Calculations TC; DI ID HF-DRAINAG AREA acE DENUDED AREAWIDTH LENGTH BOTTOM ft ELEV ELEV SLOPE AR 110-ve VELOCITYDEPTH s NORMAL D ft C L ] LINER STAPLE PATTERN Temporary Diversion Ditch 1 Temporary Diversion Ditch 2 0.58 2.31 0.28 1.34 123 198 2 2 639.2 640.0 636.5 636.8 2.2% 1.60A 2.62 1 12.12 0.35 1.49 0.35 1.9"1 DS75 DS75 Temporary Diversion Ditch 3 1.61 0.37 497 2 646.0 636.5 1.97/o 7.32 0.35 0.35 P300 Permanent Bypass Ditch 2.03 0.3=1 462 1 0 646.0 1 634.5 2.5% 9.23 4.11 0.84 P300 11 Offsite Ditch 0.86 1 0.86 1 162 1 2 645.0 1 639.0 3.7% 3.93 1 2.57 0.66 '300 Design Criteria 10-year rainfall 7.58 in/hr Side slope: 3 H:1V Coefficient: 0.6 Page 19 of 140 LEVEL SPREADER CALCULATIONS Page 20 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality C-9. Level Spreader -Filter Strip (LS-FS) Aa level spreader -filter strip (LS-FS) consists of an LS that is typically a poured concrete lip and a FS that is graded and grassed that filter and infiltrate stormwater. The LS does not remove pollutants by itself; however, it is an indispensable device needed to bring about pollutant removal in the FS. The vegetation and soils in the FS remove pollutants primarily via filtration and infiltration. The LS-FS is a Secondary SCM. The design intensity for an LS-FS is 0.75 inch per hour. Rule 15A NCAC 2H .1059. MDC for Permeable Pavement SCM Credit Document, C-9. Credit for Level Spreader -Filter Strips C-9. Level Spreader -Filter Strip 1 Revised: 1-3-2017 Page 21 of 140 NCDEQ Stormwater BMP Manual Environmental Quality Figure 1: Plan View of an LS-FS Adjacent to a Riparian Buffer pi.,Forccd Pieter Strip Zone 2 Buffer Zc0a I Buffer 3g wrap 30 a 5,U R 20 !t 34 it t xr`} Pram f`tow 50M. C4— 'a #49t�hcd �� Mind Swale a� Urldimirain - 512ad Far Site Soil Condlt!ans [pra;n lato .055 5wae IvJ457 '. _ DIrEGtIPfI 5preaficr by Fcltcr Fabm of Flow Figure 2: Cross -Section of an LS-FS 5 ft 1 ft 3 ft ■- -se sE +e Underdra (optional) I-evel spreader Swale Appropriately Sized Footer 30 or 50 ft Vegetative Filter Strip is Stone I C-9. Level Spreader -Filter Strip 2 Revised: 1-3-2017 Page 22 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality Guidance on the MDC LS-FS MDC 1: Level Spreader Length The level spreader shall be a minimum of ten feet in length per one cubic foot per second of stormwater flow that is directed to it. Figure 3: Level Spreader Lip (NCSU) The designer should calculate the peak flow during the design intensity (0.75 inches per hour) and multiply that result by 10 feet per cfs to determine the required length of the level spreader. This length requirement is based on achieving a non -erosive velocity throughout the FS and an overland flow depth of approximately 1.2 inches across the FS. This allows the FS to work effectively in removing TSS, nutrients and other pollutants via filtration and infiltration. LS-FS MDC 2: Required Storm Intensity and Bypass The required storm intensity and bypass system shall be based on the source of the stormwater: (a) A level spreader that receives flow directly from the drainage area shall be sized based on the flow rate during the 0.75 inch per hour storm, with a flow bypass system for larger storm events; or (b) A level spreader that receives flow from an SCM shall be sized based on the draw down rate of the design volume, with a flow bypass for larger storm events. Flows exceeding the ten foot per cubic foot per second capacity of the LS shall be bypassed via a flow splitter device. See Part A for more information on designing flow splitters. The flow splitter should direct the excess flows to either: • An existing drainage ditch that is located near the LS-FS, • A pipe to the receiving stream or storm drainage system, or • A newly constructed channel to the stream or storm drainage system. If a bypass channel is being used, then the designer should compute the velocity in the channel and provide appropriate reinforcement if needed. Turf reinforcement is preferred where velocities and erosive forces are not excessive (as on mild slopes) and where sufficient light is available to support turf. However, often these conditions will not exist within a riparian buffer and rip rap will be necessary. If the bypass channel discharges to a stream, then it shall enter the stream at an angle. Perpendicular entry points are likely to cause erosion on the opposite stream bank (see Figure ?). The bypass channel should discharge into a pool (deep section) of the stream. At the point of entry, stream banks may need to be protected with riprap or other engineered solution. If a C-9. Level Spreader -Filter Strip 3 Revised: 1-3-2017 Page 23 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality bypass pipe is being used, it can be discharged to a culvert rather than directly to the stream to minimize erosion issues. Please note that bypass channels through protected riparian buffers will require a buffer authorization from the DEQ 401 Permitting Unit. On the "NO" side, both of the bypass channels are poorly designed. One option enters the stream at a right angle, which may cause erosion to the opposite stream bank. In the other option, the bypass channel cuts through the FS, creating channelized flow and reducing the effectiveness of the FS. YES Figure 4: Bypass Channel Design (Winston 2010) Pool Area Existing Draw_- Level Spreader Lip Receiving Stream Zone ! t Direction of Flow NOReceivng Stream 30 it V F5 - f( i one tort Level Spreader Lip Direction of Flow LS-FS MDC 3: Exception from Flow Bypass Requirement A flow bypass system is not needed if the level spreader is sized to handle the flow during 10-year storm event. A bypass channel is not needed if the LS-FS is designed to handle the entire flow from the 10- year storm event. This will typically be the case only for very small drainage areas. C-9. Level Spreader -Filter Strip 0 Revised: 1-3-2017 Page 24 of 140 NCDEQ Stormwater BMP Manual Environmental Quality LS-FS MDC 4: Blind Swale Immediately upslope of the level spreader, there shall be a blind swale or other method of ponding water. The blind swale shall be designed to provide for uniform overtopping of the level spreader. Within a blind swale, water rises and falls evenly over the lip of the LS, which distributes the flow evenly to the FS. The blind swale is typically constructed from earth and is covered with turf or possibly lined with rip rap. If the LS-FS is being installed in soils with a low infiltration rate, then an underdrain is recommended. The underdrain will drain the blind swale between storms to provide capacity for the next storm, prevent turf from dying and avoid mosquito risk. The underdrain should discharge into the bypass channel. Another option is to construct the blind swale as a linear wetland. This option is especially useful in areas with Triassic Basin soils that have extremely low infiltration rates that are not conducive to proper functioning of an underdrain. Whenever practical, stormwater should be conveyed to the blind swale parallel to the LS to avoid short-circuiting the LS. This photo shows a LS receiving concentrated flow from a pipe, and dispersing it across its length. However, if this pipe were flowing closer to capacity, water would easily overtop the LS prior to flow being spread across its length. Also, a larger forebay than that shown is needed to still flow before it enters the blind swale. Ideally, the designer should force flow to enter the blind swale parallel to the LS to provide the best chance for diffuse flow as shown. Figure 5: Blind Swale Entrance Angles YES NO Credit: Jessica Bolin, Town of Apex Credit: Ryan Winston, NCSU C-9. Level Spreader -Filter Strip 5 Revised: 1-3-2017 Page 25 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality LS-FS MDC 5: Level Spreader Specifications The lip of the level spreader shall be at a uniform elevation with a construction tolerance of plus or minus 0.25 inch at any point along its length. The level spreader shall be constructed of concrete or other stable material. The LS consists of a poured concrete weir. Level spreaders may not be constructed from lumber, PVC pipe or earth. The lip of the LS should be 3 inches higher than the existing ground (downslope side) and anchored into the soil with an appropriately -sized concrete footer. Earthen or concrete berms may be placed at each end of the LS to prevent bypass of runoff. LS-FS MDC 6: Level Spreader Shape The level spreader shall be straight or convex in plan view. Level spreaders may not be concave in plan view because this concentrates flow downslope of the LS. This is illustrated in Figure 6 below. To minimize the grading needed to install the LS, it should be sited such that it is approximately parallel to contour lines. Figure 6: Level Spreader Configurations YES YES NO ., Required distances for the LS-FS from surface waters depend on the applicable rules: • The entire LS must be placed outside of riparian buffers and stormwater setbacks. • An FS may not be placed within either zone of a riparian buffer. However, it may be placed within a stormwater setback/buffer. • If a riparian buffer or stormwater setback/buffer exceeds the allowable slope (five or eight percent depending on the vegetation) then an LS may not be used. • Wetlands will be allowed within the FS only on a case -by -case basis. C-9. Level Spreader -Filter Strip 6 Revised: 1-3-2017 Page 26 of 140 NCDEQ Stormwater BMP Manual Environmental Quality LS-FS MDC 7: Transition Zone Immediately downslope of the level spreader, there shall be a one to three-inch drop followed by a transition zone that is protected from erosion via aggregate or high performance turf reinforcement matting. The transition zone shall be a minimum of 12 inches wide. The transition zone downslope of the LS provides erosion protection and flow dissipation. If aggregate is used, then the recommended depth is three to four inches. If geotextile fabric is used, then it should be selected based on the soil type (sand, silt or clay). LS-FS MDC 8: Minimum Width of the Filter Strip The minimum width of the filter strip shall be 30 feet, measured perpendicular to the level spreader lip. For new projects, the minimum width of the filter strip is 30 feet; however, there is a design variant below that allows for widths of less than 30 feet for retrofit projects if a longer LS is provided. See Design Variant 1 below for more information. LS-FS MDC 9: No Draws or Channels in the Filter Strip The filter strip shall not contain draws or channels. The FS should have uniform slope (equal elevations at Al, A2, A3, A4 and A5). In addition, the elevations at B1-B5 should be equal and the elevations at Cl-05 should be equal. Furthermore, the slope between the LS and the end of the filter strip will be uniform and constant. Figure 7: FS with Uniform Slope (Plan and Profile Views) A2 B2 • 2 •3 •B33 • A4 B4 C4 • A5 • B5 • C5 C-9. Level Spreader -Filter Strip 7 Revised: 1-3-2017 Page 27 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality LS-FS Recommendation 1: Pretreatment Pretreatment via the use of a forebay is recommended when the LS-FS receives flow from the drainage area. It recommended that stormwater directly from the drainage area be directed to an excavated, bowl -shaped forebay that slows the stormwater and allows sediment and debris to settle out. It is typically lined with Class B riprap. The surface area of the forebay should be equivalent to 0.2% of the contributing area's impervious surface. The recommended depth is three feet where the stormwater enters the forebay with the depth sloping up to one foot where the stormwater leaves the forebay. This design promotes settling of sediment and flow dissipation. Figure 8 shows a schematic of a forebay specifically designed for use with a LS. If the entire blind swale is lined with rip rap, then a forebay is not required. Lining the blind swale with riprap may more cost-effective for a relatively short LS. Figure 8: Schematic of a Forebay (Hathaway and Hunt 2006) Pipe From Diversion Influent To Blind �— 5tormwater 5wale 3 it LS-FS Recommendation 2: Soil Amendment It is recommended to amend the soil in the FS to promote plant growth. The FS and side slopes should be covered with at least six inches of stockpiled topsoil, imported topsoil or a combination of the two. It is recommended to test the soil and amended it according or otherwise to follow the general amendment requirements given below. If possible, mix 1 to 2 cubic yards of peat moss or compost per 1,000 square feet into the topsoil to increase soil fertility. In addition, a one-time fertilizer application to the topsoil should be specified. See Table 1 for guidance on the start-up fertilization of FS topsoil. C-9. Level Spreader -Filter Strip 8 Revised: 1-3-2017 Page 28 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality Table 1: Start-up Fertilizer Application (NCSU Cooperative Extension Service 2008) Send approximately 1 cup of the air-dried soil sample to the NCDA & CS Agronomic Division Soil Testing Services, 1040 Mail Service Center, Raleigh NC 27607. Boxes and forms can be obtained at your county Cooperative Extension center or at the Agronomic Division office in Raleigh. Allow several weeks for the results to be returned. Apply the amount of lime and fertilizer recommended for your soil by the soil testing laboratory. For additional information about interpreting a soil test, visit this Web site: http://www.ncaqr.com/agronomi/uvrst.htm Apply the following for grasses other than centipede': 75 Ibs of ground limestone per 1,000 sq ft. A starter type fertilizer (one that is high in phosphorus) based on the type of grass and the planting method. Fertilizer bags have a three -num- ber system indicating the primary nutrients, such as 8-8-8 or 5-10-10. These numbers denote the N- P-K ratio —the percentage of each nutrient in a fertilizer. The percentages are noted in the following order: N Nitrogen for green color and growth. P2O5 Phosphorus for good rooting. K2O Potassium to enhance pest and environmental stress tolerance. Common examples of starter fertilizers required for a 1,000 sq ft area include 40 Ibs of 5-10-10, 20 Ibs of 10-20-20, or 16 Ibs of 18-24-6. For sandy soils, typical to the Coastal Plain and Sandhills, fertilizer rates should be increased by 20 percent. For centipede grass, apply'/2 pound of nitrogen per 1,000 square feet. Too much fertilizer will kill centipede. LS-FS Recommendation 3: Grass Specification for FS Non -clumping, native, deep-rooted grasses should be specified in the FS. Non -clumping, native, deep-rooted grasses, such as Blue Grass or Bermuda, should be specified in FS design. Recommended grasses for the Mountains, Piedmont, and Coastal Plain are identified in Table 2. These grasses should require little maintenance. Sod grown in non - clayey soils or washed sod should be specified in the FS. It is crucial to specify frequent watering for the first three weeks of sod installation so that the first 1.5 inches of soil is kept moist. Table 2: Appropriate Grasses for FS by Region (Winston and Hunt 2009) Mountains Blue Grass, Tall Fescue Piedmont Tall Fescue, Common Bermuda Coastal Plain Centipede, Common Bermuda C-9. Level Spreader -Filter Strip 9 Revised: 1-3-2017 Page 29 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality Construction In the field prior to construction, the designer should verify that: Proposed ground contours are approximately parallel to the LS location called for in the plans. If not, the LS should be re -oriented to minimize grading. The appropriate width (30 feet) is available for the FS. The FS does not include any unaccounted for wetland areas. Wetland areas may not be graded without an appropriate permit. The LS-FS should be protected from sediment and stormwater flows during construction. A temporary stormwater diversion will likely be necessary until the drainage area and the LS-FS have fully stabilized. Grading the FS is the first step in the construction sequence. Grade the site to the design slope using a box blade or similar equipment. Care should be taken to avoid driving heavy equipment through the Engineered Filter Strip to prevent compaction. After the FS is graded, then proceed with constructing the blind swale and LS as shown in Figures 9 through 11 below. The blind swale and LS should be constructed next. Using a small excavator (or back hoe), dig a rectangular hole large enough for the "blind" swale and LS. It should nominally be dug to a depth of 1 ft, or the design depth of the LS. The LS should be constructed on undisturbed soil whenever possible. If the use of fill is unavoidable, compact the soil to 95% of standard proctor test prior to construction. A LS to date is more easily cast in place rather than pre -cast (although pre -cast options may become more commonly used). If cast in place, forms will be built for the LS. It is critical that the top of the forms are level. Figure 9: Excavating the Blind Swale (NCSU-BAE) H r`'• j'. `'• i eel. The LS should be placed at the far downslope end of the excavated area, and the forms should be approximately 3" higher than the soil downslope to allow for diffuse flow to occur. Concrete is poured to the top of the forms. Depending on the length of the LS, this can be done by mixing concrete onsite or by having concrete delivered. Once the concrete is poured, ensure that the top surface of the concrete is level by using a wooden dowel (or similar) to screed excess concrete from above the top of the forms. C-9. Level Spreader -Filter Strip 10 Revised: 1-3-2017 Page 30 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality, Figure 10: Forming the Level Lip (NCSU-BAE) aw- id 4+ a do 1 Concrete should be allowed to set overnight. The wooden forms can then be removed to reveal the finished LS. If the underlying soil is poorly drained, consider installing an underdrain upslope of the LS to drain the blind swale. Sod is strongly preferred for the blind swale. In urban applications, the blind swale may be concrete. An advantage of a concrete channel is the relative ease in accumulated debris removal (maintenance). Following construction of the LS and blind swale, the forebay should be constructed using a small excavator. The forebay should be lined with riprap to dissipate flows and protect against erosion. Consider placing an underdrain under the forebay if the underlying soils are high in clay or silt content. w. Figure 11: LS and Blind Swale Post - Construction i C-9. Level Spreader -Filter Strip 11 Revised: 1-3-2017 Page 31 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality Construct an overflow swale adjoining the FS using a small excavator. Sod should be used to vegetate the swale if low velocities and high sunlight are expected. If stormwater is expected to reach highly erosive velocities or if sunlight penetration is not expected, class B rip -rap should be used to line the swale. A diversion box may then be installed. This structure should be installed at the outlet of the watershed, to split flow between the forebay and the overflow swale as determined by the engineering designs The FS soils must be left "loose" — this can be achieved by raking, tilling or using a field cultivator. After the FS soils have been loosened, six inches of topsoil should be added to the FS and any adjacent side slopes created by grading. The topsoil can be obtained from a stockpile, off -site area or a combination of the two. Based on the soil test report recommendations or the fertilization guidelines in Table 2, incorporate lime and fertilizer into the topsoil using a disk or rototiller. Regardless of the region, a deeper root system is able to extract more moisture and nutrients from the soil, improving drought tolerance and overall health of the plant. An appropriate species of grass should be planted at the correct planting. Before planting, water the area to enhance settling. Fill areas that settle unevenly to avoid standing water. Follow these steps to install the sod in an FS (NCSU Cooperative Extension Service 2008): 1. Make sure the soil is moist (but not overly wet) before laying sod. Irrigating the soil several days before delivery is often adequate. 2. Install the sod within 24 hours of delivery. Plan to unstack and unroll the sod if it cannot be laid within 48 hours. 3. While installing, keep sod in the shade to lessen the chance of heat buildup. 4. Start sodding from a straight edge (driveway or sidewalk), and butt strips together, staggering them in a bricklike pattern (See Figure 5). 5. Avoid stretching sod. Use a knife or sharp spade for trimming to fit irregularly shaped areas. 6. Lay sod lengthwise across the face of slopes, and peg or stake the pieces to prevent slippage. 7. After the sod has been placed, roll the lawn to ensure good sod -to -soil contact. Then begin watering. For a complete list of North Carolina sod producers and the varieties they carry, visit the North Carolina Sod Producers Association Web site: http://www.ncsod.org. Again, to ensure high quality and better chance for success, it is highly recommended that certified sod be used. A list of producers growing certified sod can be found on the NCCIA Web site: http://www.nccia.ncsu.edu/. After the sod is planted, keep the top 1.5 inches of the soil moist. This may require light watering several times a week for 7 to 21 days. C-9. Level Spreader -Filter Strip 12 Revised: 1-3-2017 Page 32 of 140 NCDEQ Stormwater BMP Manual Environmental Quality Maintenance A LS-FS that is not maintained properly may become a source of pollution rather than a pollutant removal mechanism. During the first two years after construction, the LS-FS should be inspected after every major storm event for proper distribution of flows and signs of erosion. After the first two years, the LS-FS may be inspected quarterly. If evidence of erosion exists, the eroded areas should be filled in and reseeded and the cause of the erosion should be determined and eliminated. Maintenance of an FS involves routine mowing and replanting grass when necessary. Strips that receive excessive sediment may require periodic regrading and reseeding of their upslope edge because deposited sediment can kill grass and prevent the LS-FS from achieving diffuse flow. Figures 12 through 14 show a number of common maintenance issues with LS-FS systems. The job of a forebay is to collect leaves, trash and sediment before stormwater is discharged to the blind swale. Therefore, this is the part of the LS-FS that needs the most frequent maintenance. The forebay must be checked frequently and will need to be cleaned out throughout the year, particularly in the fall. In case you can't see the LS, it is immediately to the left of the yellow line. The vegetation in the blind swale has become overgrown and taken up nearly all the capacity of the blind swale. The blind swale was likely undersized in its design. Figure 12: Clogged Forebay (left) and Unmaintained Blind Swale (right) C-9. Level Spreader -Filter Strip 13 Revised: 1-3-2017 Page 33 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality During the mowing season, the FS should be mowed at least every other week. The mowing allows an opportunity for the FS to be inspected and also helps to prevent clumping of grass. This is a view upslope of the same FS at right. The clumping of the unmown grasses and resulting channelization of flow is evident from this view. The eroding areas in this FS need to be filled in and revegetated before the problem becomes worse. Figure 13: Unmaintained Blind Swale and Unmown FS Figure 14: Erosion in the FS C-9. Level Spreader -Filter Strip 14 Revised: 1-3-2017 Page 34 of 140 NCDEQ Stormwater BMP Manual En vironmental Quality Important maintenance procedures: • Immediately after the FS is established, grass will be watered twice weekly if needed until the plants become established (commonly six weeks). • Stable groundcover will be maintained in the drainage area to reduce the sediment to the LS-FS. • Every two weeks during the growing season, the FS will be mowed. Turf grass should not be cut shorter than 4-6 inches and may be allowed to grow as tall as 12 inches depending on aesthetic requirements (NIPC, 1993). • Once a year, the soil will be aerated if necessary and the FS will be reseeded to maintain a dense growth of vegetation. • Once a year, soil pH will be tested and lime will be added if necessary. For the first two years after the LS-FS is established, it will be inspected quarterly and within 24 hours after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County). After two years of successful performance, the LS-FS will be inspected quarterly. Records of operation and maintenance will be kept in a known set location and will be available upon request. If the soil in the FS becomes compacted, consider coring to alleviate this condition. Use a device that removes soil cores. Coring should be accomplished when the lawn is actively growing so that it can recover from any injury. Core cool -season grasses in fall or early spring. Core warm -season grasses in late spring or early summer. Some lawn care and landscape companies offer coring service if rental equipment is not available. Inspection and maintenance shall be performed per Table 3 below. Table 3: Sample Operation and Maintenance Provisions for LS-FS The entire LS-FS The flow splitter device (if applicable) The blind swale The LS C-9. Level Spreader -Filter Strip Trash/debris is present. The flow splitter device is clogged. The flow splitter device is damaged. The swale is clogged with sediment. The swale is overgrown with vegetation. The level lip is cracked, settled, undercut, eroded or otherwise damaged. 15 Remove the trash/debris. Unclog the conveyance and dispose of any sediment off -site. Make any necessary repairs or replace if damage is too large for repair. Remove the sediment and dispose of it off -site. Mow vegetation. Re -grade and vegetate if the swale has become silted in. Repair or replace lip. Revised: 1-3-2017 Page 35 of 140 NCDEQ Stormwater BMP Manual Environmental Quality There is erosion around the Regrade the soil to create a berm that is end of the level spreader that higher than the level lip, and then plant a shows stormwater has ground cover and water until it is bypassed it. established. Provide lime and a one-time fertilizer application. Trees or shrubs have begun Remove them. to grow on the swale or just downslope of the level lip. The bypass channel Areas of bare soil and/or Regrade the soil if necessary to remove erosive gullies have formed. the gully, and then reestablish proper erosion control. Turf reinforcement is Study the site to see if a larger bypass damaged or ripap is rolling channel is needed (enlarge if necessary). downhill. After this, reestablish the erosion control material. The FS Grass is too short or too long Maintain grass at a height of (if applicable). approximately three to six inches. Areas of bare soil and/or Regrade the soil if necessary to remove erosive gullies have formed. the gully, and then plant a ground cover and water until it is established. Provide lime and a one-time fertilizer application. Sediment is building up on Remove the sediment and restabilize the the filter strip. soil with vegetation if necessary. Provide lime and a one-time fertilizer application. Grass is dead, diseased or Determine the source of the problem: dying. soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application. Nuisance vegetation is Remove vegetation by hand if possible. choking out grass. If pesticide is used, do not allow it to get into the receiving water. The receiving water Erosion or other signs of Contact the NC Division of Water damage have occurred. Resources. C-9. Level Spreader -Filter Strip 16 Revised: 1-3-2017 Page 36 of 140 EROSION CONTROL CALCULATIONS Page 37 of 140 Carolina Pets Urban Design Partners JOB NO.: 19-027 BY: UDP 1213 W Morehead St Suite 450 DATE: 10/12/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 7/12/21 Skimmer Sediment Basin Design SKIMMER SEDIMENT BASIN DRAINAGE AREAS/REQ'D STORAGE DESIGN CRITERIA Total drainage area (TDA) 3.31 ac Proposed sediment depth 1.5 ft Disturbed area(DA) 2.51 ac Bottom elevation of basin 630.1 msl Required sediment storage (1,800 CF x DA) 4,518 cf Side slopes (H:V) 3 :1 Required surface area (325 SF per CFS 'Qio') 4,350 sf Depth of flow over spillway 0.5 ft Freeboard Height 1.0 ft BASIN CONFIGURATION PLANNED BASIN SIZE REFER TO EROSION CONTROL PLAN Bottom Elevation 630.10 msl Top of Sediment Storage Elevation 631.60 msl F Elevo Area S Cumulative Volume C Spillway Elevation 634.60 msl 630.10 0 0 Top of Berm 636.10 msl 630.60 631.60 632.60 3,266 4,154 4,731 817 4,527 8,969 BASIN EFFICIENCY Sediment Storage Required: Sediment Storage Provided: 4,518 cf 4,527 OKAY 633.60 5,689 14,179 634.60 6,703 20,375 Surface Area Required: Surface Area Provided: 4,350 sq ft 6,703 OKAY 635.60 7,773 27,613 636.10 8,329 31,639 PRIMARY SPILLWAY DESIGN 10-YEAR STORM DESIGN FLOW (Q=CIA) PRIMARY SPILLWAY DESIGN Bare soil coefficient 'C' = 0.45 Spillway design: (L=Q/(C*h^1.5)); C=3.0, h= 0.5 Area 'A' = 3.31 ac 2 yr. storm rainfall intensity, 'I' = 5.03 in/hr Required Spillway Length 10 ft 2 yr Design flow, 'Qz' = 7 cfs @ 0.50 ft flow depth 10 yr storm rainfall intensity, 'I' = 7.03 in/hr Provided Spillway Length 10 ft Desi n flow from site, 'Q ,o' = 10 cfs BASIN DEWATERING - FLOATING SKIMMER Storage Required: 4,518 cf Storage Provided: 4,527 cf Skimmer Size 6.0 in Head on Skimmer 0.42 ft Orifice Size 1.00 in Dewatering of Required Volume Dewater of Actual Volume 3.03 days 3.03 days Page 38 of 140 Carolina Pets Urban Design Partners JOB NO.: 19-027 BY: UDP 1213 W Morehead St Suite 450 DATE: 10/12/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 7/12/21 Skimmer Sediment Basin Design SKIMMER SEDIMENT BASIN DRAINAGE AREAS/REQ'D STORAGE DESIGN CRITERIA Total drainage area (TDA) 3.14 ac Proposed sediment depth 1.5 ft Disturbed area(DA) 2.51 ac Bottom elevation of basin 630.1 msl Required sediment storage (1,800 CF x DA) 4,518 cf Side slopes (H:V) 3 :1 Required surface area (325 SF per CFS 'Qio') 4,350 sf Depth of flow over spillway 0.5 ft Freeboard Height 1.0 ft BASIN CONFIGURATION PLANNED BASIN SIZE REFER TO EROSION CONTROL PLAN Bottom Elevation 630.10 msl Top of Sediment Storage Elevation 631.60 msl F Elevo Area S Cumulative Volume C Spillway Elevation 634.60 msl 630.10 0 0 Top of Berm 636.10 msl 630.60 631.60 632.60 3,266 4,154 4,731 817 4,527 8,969 BASIN EFFICIENCY Sediment Storage Required: Sediment Storage Provided: 4,518 cf 4,527 OKAY 633.60 5,689 14,179 634.60 6,703 20,375 Surface Area Required: Surface Area Provided: 4,350 sq ft 6,703 OKAY 635.60 7,773 27,613 636.10 8,329 31,639 PRIMARY SPILLWAY DESIGN 10-YEAR STORM DESIGN FLOW (Q=CIA) PRIMARY SPILLWAY DESIGN Bare soil coefficient 'C' = 0.45 Spillway design: (L=Q/(C*h^1.5)); C=3.0, h= 0.5 Area 'A' = 3.14 ac 2 yr. storm rainfall intensity, 'I' = 5.03 in/hr Required Spillway Length 10 ft 2 yr Design flow, 'Qz' = 7 cfs @ 0.50 ft flow depth 10 yr storm rainfall intensity, 'I' = 7.03 in/hr Provided Spillway Length 10 ft Desi n flow from site, 'Q ,o' = 10 cfs BASIN DEWATERING - FLOATING SKIMMER Settling Volume/Storage Required: 4,518 cf Settling Volume/Storage Provided: 4,527 cf Skimmer Size 6.0 in Head on Skimmer 0.42 ft Orifice Size 1.00 in Dewatering of Required Volume Dewater of Actual Volume 3.03 days 3.03 days Page 39 of 140 WATER QUALITY CALCULATIONS Page 40 of 140 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BDS Charlotte, NC 28208 REVISED: 12/22/21 PRELIMINARY CALCULATIONS INTRODUCTION: Onsite stormwater runoff will be collected through a pipe network and treated using a dry detention pond with a sand filter, located at the southwest corner of the site. Overall drainage area is 11 acres; drainage area to pond is 1.52 acres. U11.El101L-TN:W-0V M M SOIL TYPES: (see attached drainage area map) Predevelo ed Drainage Area 11.00 acres Postdevelo ed Drainage Area 11.00 acres (see attached soils map) Area ac Area % Soil Type Hydrologic Soil Group 11 100% TbB2 0% 0% Total 1 11 100% CURVE NUMBER: Pre Development DA #1 Cover Type Area ac % CN Wtd. CN Grass/Open Space 1.58 28% 69 19.26 Woods 2.91 51 % 60 30.85 Impervious 1.17 21 % 98 20.26 Total 5.66 70.37 Com osite CN Use CN = 70.00 Pre Development DA #2 Cover Type Area ac % CN Wtd. CN Grass/Open Space 0.09 11 % 69 7.39 Woods 0.75 89% 60 53.57 Impervious 0 0% 98 0.00 Total 0.84 60.96 Com osite CN Use CN = 61.00 Pre Development DA #3 Cover Type Area ac % CN Wtd. CN Grass/Open Space 0.32 7% 69 4.91 Woods 4.18 93% 60 55.73 Impervious 0 0% 98 0.00 Total 4.50 60.64 Com osite CN Use CN = 61.00 Bypass Ditch DA Cover Type Area ac % CN Wtd. CN Woods 0.45 22% 60 13.30 Grass 1.58 78% 69 53.70 Impervious 0 0% 98 0.00 Total 2.03 67.00 Com osite CN Use CN = BMP Treated DA Cover Type Area ac % CN Wtd. CN Grass/Open Space 0.42 28% 1 69 19.08 Woods 0 0% 60 0.00 Impervious 1.10 72% 98 70.91 Total 1.52 89.98 Com osite CN Use CN = 90.00 Untreated DA #1 Cover Type Area ac % CN Wtd. CN Grass/Open Space 1.15 31 % 1 69 21.16 Woods 1.43 38% 60 22.88 Impervious 1.17 31 % 9 30.58 Total 3.75 74.62 Com osite CN Use CN = 75.00 Untreated DA #2 Cover Type Area ac % CN Wtd. CN Grass/Open Space 0.14 4% 1 69 2.61 Woods 3.56 96% 60 57.73 Impervious 0 0% 98 0.00 Total 3.70 60.34 Com osite CN Use CN = 60.00 HYDROLOGIC CALCULATIONS Pre-Dev to BMP Drainage area (DA) 0.84 ac. Cuve Number (CN) 61 Modified Curve Number (CN) n/a Time of Concentration 0.35 hr. Impervious Percentage 1% WATER QUALITY VOLUME (1"a Volume must be released over a period of 2-5 days Using the runoff volume calculations in the "Simple Method" Rv = 0.05 + .009 (1) Rv= 0.70 in/in WQv = (Design rainfall) (Rv) (Drainage Area) WQv = 1" rainfall x Rv in/in x 1/12 in/ft x Da = WQv= 0.09 ac-ft 3,865 ft3 0.70 in Post-Dev to BMP 1.52 ac 90 94 0.1 hr. 72 % 75% Discount per MDC C-6 0.75*WQv= 0.07 ac-ft 2,899 cf 0.53 In MODIFIED CURVE NUMBER CNm= 1000/{10+5P+10WQV-10(WQVA2+1.25WQVP)A0.5} P= rainfall, in inches (use1.0 inches) = 1.00 WQv= water quality volume, in inches = 0.53 CNm 94.4 CHANNEL PROTECTION VOLUME Q= (P-0.2S)A2/(P+0.8S) Q= accumulated runoff volume, inches P= accumulated rainfall (potential maximum runoff), inches 3.55 in S= potential maximum soil retention, inches = 1000/CN-10 = 1.11 in CN= SCS curve number Q= 2.49 cfs Compute Watershed Runoff CPv= 0.32 ac-ft Channel Protection Volume Release Rate (1yr, 24 hr storm) 1.5 day 36 hour Release= 0.106 cfs Determine Orifice Size for drawdown Q= CA x sgrt(2gh) orifice equation aA= Area of orifice a sqft t= Time to drawdown 129,600 sec 36 hour g= Gravity constant 32.2 ft/sA2 h= Change in head 1.00 ft C= Orifice constant 0.6 Maximum orifice area = 0.0220 sq ft Maximum orifice size = 2.01 in. Carolina Pets 0 Urban Design Partners JOB NO.: 19-0 -027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/211 IMPERVIOUS CALCULATIONS IlExisting Impervious Road 1 0 sf Total Impervious Area: 0 sf 0.00 ac. Drainage Area: 4.22 BUA Percentage 0% Existing To Be Removed 0 sf BMP BUA Calculations RAAP Tmnf—i nA Ph— 1 A 9 (arrnnt fnr in nnnri ralrc) Pro osed Impervious Buildings: 10,197 sf Sidewalks 3,150 sf Parking/Road 22,581 sf Future 11,956 sf Total Impervious Area: 47,884 sf 1.10 ac. Drainage Area: 1.52 Impervious Percentage: 72% BMP % BUA 72.3% Total Site BUA Calculations layer Total Site BUA (Phase 1 & 2) Pro osed Impervious Buildings: 10,197 sf Sidewalks 3,107 sf Parking/Road 22,392 sf Future 11,956 sf Total Impervious Area: 47,652 sf 1.09 ac. Site Area 2.63 Impervious Percentage: 42% RAAP T—f—i nA Ph... 1 Pro osed Im ervious Building: 10,197 sf Sidewalks: 3,150 sf Parking/Road 22,581 Total Impervious Area: 35,928 sf 0.82 ac. Drainage Area: 1.52 Impervious Percentage: 54% BMP % BUA 54% Total Site RUA (Phase it Pro osed Impervious Buildings: 10,197 sf Sidewalk 3,107 sf Parking/Road 22,392 sf Total Impervious Area: 35,696 sf 0.82 ac. Site Area 2.63 Impervious Percentage: 31 % TOTAL SITE % BUA 41.6% TOTAL SITE % BUA 31.2% Carolina Pets Urban Design Partners JOB NO.: 19-160 BY: UDP 1213 W Morehead St ste 450 DATE: 8/28/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 SAND FILTER DESIGN Sand Filter Design Requirements Desion Method Design Method TSS Detention Time 2.0 days Filter Bed Depth 1.5 ft Underdrain System Thickness 1.0 ft Hydrologic Calculations POI #1 Pre -developed Drainage area to pond (Da)= 0.84 ac. Cuve Number (CN) 61 Adjusted Curve Number (CN) n/a Time of Concentration 0.35 hr. Impervious Percentage 1 % Water Quality Volume (1 " rainfall) Volume must be released over a period of 2-5 days Using the runoff volume calculations in the "Simple Method" Rv = 0.05 + .009 (1) Rv= 0.70 in/in WQv = (Design rainfall) (Rv) (Drainage Area) WQv = 1 " rainfall x Rv in/in x 1/12 in/ft x Da = Modified Curve Number CNm= 1000/{10+5P+10WQv-10(WQv^2+1.25WQvP)^0.5} P= rainfall, in inches (use1.0 inches) = 1.00 WQv= water quality volume, in inches = 0.53 CNm 94.4 BMP Treated DA 1.52 ac 90 94 O.1 hr. 72 % 75% Discount per MDC C-6 WQv= 0.09 ac-ft 0.75"WQv= 0.07 ac-ft 3,865 cf 2,899 cf 0.70 in O.526 in Channel Protection Volume Q= (P-0.2S)^2/(P+0.8S) Q= accumulated runoff volume, inches P= accumulated rainfall (potential maximum runoff), inches 3.55 in S= potential maximum soil retention, inches = 1000/CN-10 = 1.11 in CN= SCS curve number 90 Computer Watershed Runoff CPv= 0.32 ac-ft 6879.26 Carolina Pets Urban Design Partners JOB NO.: 19-160 BY: UDP 1213 W Morehead St ste 450 DATE: 8/28/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 SAND FILTER DESIGN Calculate Release Rates Water Quality Release Rate (1 " rainfall) 2.00 days 48 hours Release= 0.016 cfs Channel Protection Volume Release Rate (1yr, 24 hr storm) hold volume 24 hrs past center of storm (12 hr) 36 hours Release= 0.106 cfs Calculate Pretreatment System Requirements sedimentation chamber must hold 20% of the WQv Volume= 580 cf Chamber Approximate Dimensions Depth= Length= Width= 38 ft Area= 1140 sf Volume= 1,140 cf Okay Determine Suface Area to Treat WQv Surface Area based on Darcy's Equation Af= (WQv)(df)/{(k)(h+d)(t)} Af= surface area of ponding area (sq ft) WQv= water quality control volume 2,899 cf d= filter bed depth 1.5 ft k= coefficient of permeability of filter media 3.5 ft/day h= average height of water above filter bed (ft) 0.5 ft t= design filter bed drain time (days) 2.00 day Af= 311 sf Determine Dimensions Length= 20.9 ft Width= 20.9 ft Area= 437 sf Okay Stage/Storage Tables Forebay Elevation (msl) Area (sfl Area (ac) Volume (cu-ft) Volume (--ft) 631.6 0 0.000 0 0.000 632.6 1,515 0.035 504 0.012 633.6 1,889 0.043 2,201 0.051 634.6 2,294 0.053 4,287 0.098 635.6 2,727 0.063 6,792 0.156 636.1 2,955 0.068 8,211 0.189 24" max for WQ storm event Carolina Pets Urban Design Partners JOB NO.: 19-160 BY: UDP 1213 W Morehead St ste 450 DATE: 8/28/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 SAND FILTER DESIGN Sand Filter Chamber Elevation (msl) Area (sf) Area (ac) Volume (cu-ft) Volume (--ft) 631.1 0 0.000 0 0.000 631.6 1,549 0.036 258 0.006 632.6 1,928 0.044 1,991 0.046 633.6 2,334 0.054 4,117 0.095 634.E 2,770 1 0.064 1 6,663 1 0.153 635.E 3,234 0.074 9,659 0.222 636.1 3,477 0.080 11,335 0.260 Total storage Elevation (msl) Area (sf) Area (ac) Volume (cu-ft) Volume (--ft) 631.1 0 0.000 0 0.000 631.6 1,549 0.036 258 0.006 632.6 3,443 0.079 2,689 0.062 633.6 4,223 0.097 6,512 0.149 634.E 5,064 1 0.116 1 11,144 1 0.256 635.E 5,961 0.137 16,645 0:382 636.1 6,432 0.148 19,740 0.453 Stage/Discharge Table Q= Af(k)(h+d)/(d) p Af= surface area of ponding area (sq ft) 437 sf d= filter bed depth 1.5 ft k= coefficient of permeability of filter media 3.5 ft/day h= average height of water above filter bed (ft) Elevation (msl) Height (ft) Fow (cf/day) Flow (cfs) 631.1 0.0 0 0.000 631.6 0.5 2,038 0.024 632.6 1.5 3,058 0.035 633.6 2.5 4,077 0.047 634.6 3.5 5,096 0.059 635.6 4.5 6,115 0.071 636.1 5.0 6,625 0.077 Water Quality Surface Elevation (interpolation) Elev Storage Volume Storage Area 632.6 Elev 633.6 0.062 0.067 0.149 3,443 3,486 4,223 Tem . Storage Elev: 632.65 ft. above perm. pool elev. Tem . Pool Elev: 632.65 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 TIME OF CONCENTRATION WORKSHEET PRE -DEVELOPMENT DA #1 & UNTREATED DA #1 SHEET FLOW Max. Elevation: 654.5 Min. Elevation: 651 Flow Length (ft): 150 Slope: 2.33% Mannings: 0.24 Table 2-13 SWDM Precipitation: 3.55 2-yr, 24-hr rainfall Travel Time: 0.29 hr Eq. 2.9 SWDM SHALLOW CONCENTRATED Max. Elevation: 651 Min. Elevation: 634.5 Flow Length (ft): 808.85 Slope: 2.04% Velocity (fps): 9.33 Eq. 2.16 SWDM Travel Time: 86.67 sec 0.024 hr CHANNEL FLOW Flow Length (ft): 255.33 Velocity (fps): 3 assumed 3 ft/sec Travel Time: 85.11 sec pl 0.024 hr TIME OF CONCENTRATION Total: 0.34 hr 20 min Page 8 of 12 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 TIME OF CONCENTRATION WORKSHEET PRE -DEVELOPMENT DA #2 SHEET FLOW Max. Elevation: 652 Min. Elevation: 646.5 Flow Length (ft): 150 Slope: 3.67% Mannings: 0.24 Table 2-13 SWDM Precipitation: 3.55 2-yr, 24-hr rainfall Travel Time: 0.25 hr Eq. 2.9 SWDM SHALLOW CONCENTRATED Max. Elevation: 646.5 Min. Elevation: 627.8 Flow Length (ft): 381 Slope: 4.91 % Velocity (fps): 3.57 Eq. 2.15 SWDM Travel Time: 106.59 sec 0.030 hr CHANNEL FLOW Flow Length (ft): 69 Velocity (fps): 3 assumed 3 ft/sec Travel Time: 23.00 sec pl 0.006 hr TIME OF CONCENTRATION Total: 0.28 hr 17 min Page 9 of 12 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 TIME OF CONCENTRATION WORKSHEET PRE -DEVELOPMENT DA #3 & UNTREATED DA #2 SHEET FLOW Max. Elevation: 652.3 Min. Elevation: 648 Flow Length (ft): 150 Slope: 2.87% Mannings: 0.4 Table 2-13 SWDM Precipitation: 3.55 2-yr, 24-hr rainfall Travel Time: 0.41 hr Eq. 2.9 SWDM SHALLOW CONCENTRATED Max. Elevation: 648 Min. Elevation: 623.5 Flow Length (ft): 465 Slope: 5.27% Velocity (fps): 3.70 Eq. 2.15 SWDM Travel Time: 125.56 sec 0.035 hr CHANNEL FLOW Flow Length (ft): 690 Velocity (fps): 3 assumed 3 ft/sec Travel Time: 230.00 sec pl 0.064 hr TIME OF CONCENTRATION Total: 0.51 hr 30 min Page 10 of 12 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 TIME OF CONCENTRATION WORKSHEET BYPASS DITCH DA SHEET FLOW Max. Elevation: 654.5 Min. Elevation: 652 Flow Length (ft): 150 Slope: 1.67% Mannings: 0.24 Table 2-13 SWDM Preci itation: 3.55 2- r, 24-hr rainfall Travel Time: 0.34 hr Eq. 2.9 SWDM SHALLOW CONCENTRATED Max. Elevation: 650.8 Min. Elevation: 646 Flow Length ft : 127 Slope: 3.78% Velocity (fps): 3.14 E . 2.15 SWDM Travel Time: 40.49 sec 0.011 hr CHANNEL FLOW Flow Length ft : 446 Velocity (fps): 4.11 "Per North American Green Matting Calculations: =Q/A Travel Time: 108.52 sec PI 0.030 hr TIME OF CONCENTRATION Total: 0.38 hr 23 min Page 11 of 12 Carolina Pets Urban Design Partners JOB NO.: 19-CLT-027 BY: UDP 1213 W Morehead St ste 450 DATE: 10/8/20 P.M.: BIDS Charlotte, NC 28208 REVISED: 12/22/21 FLOATATION CALCULATIONS ML Calculations Given Data N Standard Footing Assumptions Buoyant Weight of Concrete 87.6 Ibs/ft^3 1. Footing base to be 1 ft. wider than structure on all sides. 2. Footing depth to be a minimum of 8 inches in depth. Weight of Water 62.4 Ibs/ft^3 Safety Factor (S.F.) 1.25 Equations used: Outlet Structure Weight, W(s) = 4(w + t) x t x h x W(bc) where, w = outlet box inside dimension, ft. t = structure wall thickness, ft. h = height of structure, ft. W(bc)= buoyant weight of concrete, Ibs/ft^3 W(w)= weight of water, Ibs/ft^3 S.F.= safety factor Displaced Water Weight, W(w) = 4 x (w + 2t) x W(w) x h Required Base Weight, W(b) = (W(w) x S.F.) - W(s) Required Footing Volume, V(f) = W(b) / W(bc) ut et Structure #1 Stru MrOb'ect Wei hts Height of structure, h = 7 ft. Outlet Structure Weight, W(s) = 5519 Ibs Structure wall thickness, t = 6 in. Displaced Water Weight, W(w) = 8736 Ibs Outlet box inside dimension, w = 4 ft. Req'd Base Weight, W(b) = 5401 Ibs Required Footing Volume, V(f) = Footing Size 62 cf Standard Footing Length, L = 7.00 ft. Provided Footing Volume, V(f) = 74 cf Standard Footing Width, W = 7.00 ft. Footing Check okay Minimum Footing Depth, D = 1.50 ft. Footing Size to be used: Length = Width = Depth = 7.00 ft' 7.00 ft. Oumr� tlet Structure #1 1.50 ft. 1-Inch Routing Page 53 of 140 2W� Est CNm Sand Filter Detention Pond Subcat Reach on Link Carolina Pet Post Type 1124-hr 1-in Rainfall=1.00" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 2WQ: Post CNm Runoff = 1.41 cfs @ 11.96 hrs, Volume= 2,779 cf, Depth= 0.50" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 1-in Rainfall=1.00" Area (ac) CN Description 1.520 94 Modified CN for WQv 1.520 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 2WQ: Post CNm Hydrograph I I II II II II II II II II II II II II II II II II II II II II II ❑Runoff 1.41 cfs ITy; pQ If 24-h'r 14n�l RainfaillT1.00" Rwnbff A'rei�=1.520 ac 1 RL;npff'IVQIL;m'e='12,17$ Gf R6noff IDepthT0.501' 3 I I I I I I I I I I I I I I I I I I I TcT5.0 tnih LL I I I I I I I I I I I I I I I I I I PN=94 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 1124-hr 1-in Rainfall=1.00" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 4 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 0.00% Impervious, Inflow Depth = 0.50" for 1-in event Inflow = 1.41 cfs @ 11.96 hrs, Volume= 2,779 cf Outflow = 0.03 cfs @ 15.81 hrs, Volume= 2,779 cf, Atten= 98%, Lag= 230.9 min Primary = 0.03 cfs @ 15.81 hrs, Volume= 2,779 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 632.15' @ 15.81 hrs Surf.Area= 2,594 sf Storage= 1,761 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 689.4 min calculated for 2,779 cf (100% of inflow) Center -of -Mass det. time= 689.9 min ( 1,518.6 - 828.7 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic)Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125'/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type 1124-hr 1-in Rainfall=1.00" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 5 Primary OutFlow Max=0.03 cfs @ 15.81 hrs HW=632.15' (Free Discharge) L1=Outlet (Passes 0.03 cfs of 14.23 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.03 cfs) 3=Low Flow Orifice ( Controls 0.00 cfs) =Grate Top ( Controls 0.00 cfs) =Weir 1 ( Controls 0.00 cfs) =Weir 2 ( Controls 0.00 cfs) Pond 313: Sand Filter Detention Pond Hyd rog raph ❑ Inflow 1.41 cfs I ❑ Primary 11nfllowAre=61,211 s Peak Elev=63'�2.151' Storage- 1 I I I I I I I I I I I I I I I I I I I I I I y I I I I I I I I I I I I I I I I I I I I I I U I I I I I I I I I I I I I I I I I I I I I I 3 I I I I I I I I I I I I I I I I I I I I I I p LL I I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 1124-hr 1-in Rainfall=1.00" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 6 Hydrograph for Pond 313: Sand Filter Detention Pond Time Inflow Storage Elevation Primary (hours) (cfs) (cubic -feet) (feet) (cfs) 0.00 0.00 0 631.10 0.00 3.00 0.00 0 631.10 0.00 6.00 0.00 0 631.10 0.00 9.00 0.00 2 631.10 0.00 12.00 1.22 1,047 631.86 0.03 15.00 0.04 1,752 632.14 0.03 18.00 0.02 1,727 632.13 0.03 21.00 0.02 1,603 632.08 0.03 24.00 0.01 1,450 632.02 0.03 27.00 0.00 1,151 631.90 0.03 30.00 0.00 863 631.79 0.03 33.00 0.00 588 631.68 0.02 36.00 0.00 331 631.52 0.02 39.00 0.00 171 631.32 0.01 42.00 0.00 88 631.21 0.01 45.00 0.00 45 631.16 0.00 48.00 0.00 23 631.13 0.00 51.00 0.00 12 631.12 0.00 54.00 0.00 6 631.11 0.00 57.00 0.00 3 631.10 0.00 60.00 0.00 2 631.10 0.00 63.00 0.00 1 631.10 0.00 66.00 0.00 0 631.10 0.00 69.00 0.00 0 631.10 0.00 72.00 0.00 0 631.10 0.00 75.00 0.00 0 631.10 0.00 78.00 0.00 0 631.10 0.00 81.00 0.00 0 631.10 0.00 84.00 0.00 0 631.10 0.00 87.00 0.00 0 631.10 0.00 90.00 0.00 0 631.10 0.00 93.00 0.00 0 631.10 0.00 96.00 0.00 0 631.10 0.00 99.00 0.00 0 631.10 0.00 102.00 0.00 0 631.10 0.00 105.00 0.00 0 631.10 0.00 108.00 0.00 0 631.10 0.00 111.00 0.00 0 631.10 0.00 114.00 0.00 0 631.10 0.00 117.00 0.00 0 631.10 0.00 120.00 0.00 0 631.10 0.00 1-YEAR Page 72 of 140 (22 BI) BMP Tre ed DA /3 \B Sand Filter Detention Pond Subcat Reach on Link Routing Diagram for Carolina Pet Post Prepared by {enter your company name here}, Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Carolina Pet Post Type 1124-hr 1-yrRainfall=2.95" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 213: BMP Treated DA Runoff = 5.25 cfs @ 11.96 hrs, Volume= 10,695 cf, Depth= 1.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 1-yr Rainfall=2.95" Area (ac) CN Description 1.100 98 Impervious 0.000 60 Woods 0.420 69 Grass 1.520 90 Weighted Average 0.420 27.63% Pervious Area 1.100 72.37% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph I I II II II II II II II II II II II II II II II II II II II II II ■Runoff 5.25 cfs TOO f Z4-hY 5r 1-yr kainfall=2;951" -- ------------------ — Runoff A►re�a=4.520a'c- 4 1 1 1 1 1 1 1 1 1 1 Rtndff IVdIu'm6=10,1695 df w --I------;--;--;-------------;--;--;--;--Runoff -Deptty=1-:194" 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 fic=5T0 Inip LL ------------- I___I___I----------- I __I___I----- _I ------I_— = _ I I I I I I I I I I I I I I I I I I I • -I 2 1 I I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 1124-hr 1-yrRainfall=2.95" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 4 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 72.37% Impervious, Inflow Depth = 1.94" for 1-yr event Inflow = 5.25 cfs @ 11.96 hrs, Volume= 10,695 cf Outflow = 0.08 cfs @ 17.81 hrs, Volume= 10,695 cf, Atten= 99%, Lag= 351.2 min Primary = 0.08 cfs @ 17.81 hrs, Volume= 10,695 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 633.80' @ 17.81 hrs Surf.Area= 4,393 sf Storage= 7,645 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 1,318.2 min calculated for 10,692 cf (100% of inflow) Center -of -Mass det. time= 1,318.9 min (2,125.0 - 806.1 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic)Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125'/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type 1124-hr 1-yrRainfall=2.95" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 5 Primary OutFlow Max=0.08 cfs @ 17.81 hrs HW=633.80' (Free Discharge) L1=Outlet (Passes 0.08 cfs of 17.94 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.05 cfs) 3=Low Flow Orifice (Orifice Controls 0.03 cfs @ 4.94 fps) =Grate Top ( Controls 0.00 cfs) =Weir 1 ( Controls 0.00 cfs) =Weir 2 ( Controls 0.00 cfs) Pond 313: Sand Filter Detention Pond Hyd rog raph 5.25 cfs I I I I1 _ L__ L__I__ J__ L__ L__I__J__ L__ L 1_ L L 1_ J L I_ -1 nf�,row A rrecj= 6,, 21 � s�- - 5 Peak Elev=63'3.8a' Sforage=, 1,6" Cf 4 y I I I I I I I I I I I I I I I I I I I I I I U �-- 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 LL 2 I I I I I I I I — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — — 1 I I I I I I I I I I I I I I I I I I I I I I I 0 , .. .. .. 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) ❑ Inflow ❑ Primary Carolina Pet Post Type 1124-hr 1-yrRainfall=2.95" Prepared by {enter your company name here} Printed 7/27/2022 HydroCAD® 10.00-26 s/n 09478 © 2020 HydroCAD Software Solutions LLC Page 6 Hydrograph for Pond 313: Sand Filter Detention Pond Time Inflow Storage Elevation Primary (hours) (cfs) (cubic -feet) (feet) (cfs) 0.00 0.00 0 631.10 0.00 3.00 0.00 0 631.10 0.00 6.00 0.00 0 631.10 0.00 9.00 0.04 143 631.28 0.01 12.00 4.46 4,666 633.06 0.06 15.00 0.12 7,464 633.76 0.08 18.00 0.07 7,644 633.80 0.08 21.00 0.05 7,477 633.76 0.08 24.00 0.05 7,197 633.70 0.07 27.00 0.00 6,435 633.52 0.07 30.00 0.00 5,715 633.33 0.06 33.00 0.00 5,052 633.16 0.06 36.00 0.00 4,447 633.00 0.05 39.00 0.00 3,904 632.86 0.05 42.00 0.00 3,437 632.74 0.04 45.00 0.00 3,043 632.64 0.04 48.00 0.00 2,667 632.51 0.03 51.00 0.00 2,309 632.36 0.03 54.00 0.00 1,967 632.23 0.03 57.00 0.00 1,641 632.10 0.03 60.00 0.00 1,330 631.97 0.03 63.00 0.00 1,033 631.86 0.03 66.00 0.00 750 631.74 0.03 69.00 0.00 481 631.64 0.02 72.00 0.00 253 631.42 0.02 75.00 0.00 131 631.27 0.01 78.00 0.00 67 631.19 0.00 81.00 0.00 35 631.14 0.00 84.00 0.00 18 631.12 0.00 87.00 0.00 9 631.11 0.00 90.00 0.00 5 631.11 0.00 93.00 0.00 2 631.10 0.00 96.00 0.00 1 631.10 0.00 99.00 0.00 1 631.10 0.00 102.00 0.00 0 631.10 0.00 105.00 0.00 0 631.10 0.00 108.00 0.00 0 631.10 0.00 111.00 0.00 0 631.10 0.00 114.00 0.00 0 631.10 0.00 117.00 0.00 0 631.10 0.00 120.00 0.00 0 631.10 0.00 2-Year Routing Page 91 of 140 Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 2 Summary for Subcatchment 213: BMP Treated DA Runoff = 6.87 cfs @ 11.96 hrs, Volume= 14,335 cf, Depth= 2.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 2-yr Rainfall=3.56" Area (ac) CN Description 1.140 98 Impervious 0.000 60 Woods 0.380 69 Grass 1.520 91 Weighted Average 0.380 25.00% Pervious Area 1.140 75.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph � � � � � � � � � � � � � � � � � � � � � ■Runoff 6.87cfs ------ - ------ ------ - 7 I Typq 11', 24-1'r ,r l�ai,nf�11=1156 6 =y 1--L-- J--1--1--L__'L RU11off Area=�1_.52.0_ai�_ 5 RUndff VbIuM6=14,335 cf N - -- - -- -- - -- -- -- - -- - -- 'ftrmff Depth 2.;5-O"- 4 fic=& O In i p LL--I---------------------------------------------I ___------- 3 4N=91 2 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 3 Summary for Link 3A: P0I#2 Inflow Area = 479,160 sf, 21.00% Impervious, Inflow Depth = 1.17" for 2-yr event Inflow = 7.55 cfs @ 12.20 hrs, Volume= 46,638 cf Primary = 7.55 cfs @ 12.20 hrs, Volume= 46,638 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 3A: P0I#2 Hyd rog raph ---I--T--T--r--I--r--T--r--I--T--T--r--I- r-- T --I - -- I--T-- T-- ■ Inflow ❑ Primary s 7.55 cfs ------- --+--- --------- '-[Wjo Area=-47gj60-sf ------------------------ s s U I I I I I I I I I I I I I I I I I I I I I 0 4 ---T-------T-- T-- r--I-- r-- T-- r--I-- T-- T-- r--I-- r-- T-----I-- T-- T -- LL 3 2 1 I I I I I I I I I I I I I I I I I I I .0 65 70 75 :0 85 90 95 100 Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 4 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 75.00% Impervious, Inflow Depth = 2.60" for 2-yr event Inflow = 6.87 cfs @ 11.96 hrs, Volume= 14,335 cf Outflow = 0.09 cfs @ 18.20 hrs, Volume= 14,335 cf, Atten= 99%, Lag= 374.6 min Primary = 0.09 cfs @ 18.20 hrs, Volume= 14,335 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 634.42' @ 18.20 hrs Surf.Area= 4,916 sf Storage= 10,544 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 1,487.7 min calculated for 14,335 cf (100% of inflow) Center -of -Mass det. time= 1,487.6 min (2,282.1 - 794.5 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 5 Primary OutFlow Max=0.09 cfs @ 18.20 hrs HW=634.42' (Free Discharge) L1=Outlet (Passes 0.09 cfs of 19.16 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.06 cfs) 3=Low Flow Orifice (Orifice Controls 0.03 cfs @ 6.24 fps) 4=Grate Top ( Controls 0.00 cfs) =Weir 1 ( Controls 0.00 cfs) =Weir 2 ( Controls 0.00 cfs) Pond 313: Sand Filter Detention Pond Hyd rog raph 6.87 cfs -II---III---- --II -- III -- -- --I -- III ---- --II --�III-- ----II---IIIj-'--- -- 7 I I I I I I I I I I IInflowII1 0=66,21 1, I sllf Peak 11 Elev=63114.42' 6 5 -- - ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- -- -- ---- y I I I I I I I I I I I I I I I I I I I I I I V4 I I I I I I I I I I I I I I I I I I I I I I 3 -- - __I___I--_I-- __1---1-- 1-- 1 --1--I---1-- 1--1---1-- 1-- 1--1---1---1-- 1 -- o I I I I I I I I I I I I I I I I I I I I I I LL 3 2 --1- -1--1---1--J--1--L--1----L--L--1--J--1--L--1----L--1---1--J--1-- 1 0.09 cfs 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) ❑ Inflow ❑ Primary Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 4S: Untreated DA #1 Runoff = 4.87 cfs @ 12.18 hrs, Volume= 18,301 cf, Depth= 1.34" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 2-yr Rainfall=3.56" Area (ac) CN Description 1.150 69 Grass 1.430 60 Woods 1.170 98 Impervious 3.750 75 Weighted Average 2.580 68.80% Pervious Area 1.170 31.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.0 Direct Entry, Post Tc Subcatchment 4S: Untreated DA #1 Hydrograph I I I I I I I I I I I I I I I I I I I I I I I ■Runoff 5 4.87 cfs - Typq 11'I II'I 24-I Ir -- -- --' -- --+-- --' -- --y-Ii kai!nfal!=3.t6 4 Runoff area=3.750 aic Rhndff VbIuM6=18,301 Cf 3 Runoff Dept h=1.',34," LL I I I I I I I I I I I I I I I I Tq=24 b Ian i p - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1 I I I I I I I I I I I I I I I I I I I I I I 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 7 Summary for Link 5L: POI #1 Inflow Area = 229,561 sf, 43.83% Impervious, Inflow Depth = 1.71" for 2-yr event Inflow = 4.95 cfs @ 12.18 hrs, Volume= 32,636 cf Primary = 4.95 cfs @ 12.18 hrs, Volume= 32,636 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 5L: POI #1 Hyd rog raph ----I__-'I--' ■ Inflow _--------------'--- ❑Primary -----;-------I0f�o�nrJ�real=�►29,561'; s;f 4.95 cfs �� s 4 --I -T-------T--T--r----r--T--r----T--?--r--I--r--T-------T--?-- y I I I I I I I I I I I I I I I I I I I I I u 3 3 I I I I I I I I I I I I I I I I I I I I I 0 LL 2 J__ 1__L__I__J__1__I--- I__J__1__ 60 65 70 75 :0 85 90 95 100 Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 6S: Bypass Ditch DA Runoff = 1.61 cfs @ 12.19 hrs, Volume= 6,514 cf, Depth= 0.88" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 2-yr Rainfall=3.56" Area (ac) CN Description 0.000 98 Impervious 0.450 60 Woods 1.580 69 Grass 2.030 67 Weighted Average 2.030 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 Direct Entry, Post Tc Subcatchment 6S: Bypass Ditch DA Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ❑Runoff 1.61 cfs ,Type W 24-hr 2r r R'ainfaillT3.a6" Run6ffAwe&2.030 at -- -'-- --+----------'-- -- -- --R4n_Off'V_QI_um!e=6,$14-rf- 1 Runoff DepthT0.881, Td=23.�0 tnih GN=67 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) 10-Year Routing Page 101 of 140 Carolina Pet Post Type/1 24-hr 2-yr Rainfall=3.56" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 7S: Untreated DA #2 Runoff = 1.23 cfs @ 12.31 hrs, Volume= 7,488 cf, Depth= 0.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 2-yr Rainfall=3.56" Area (ac) CN Description 0.000 98 Impervious 3.560 60 Woods 0.140 69 Grass 3.700 60 Weighted Average 3.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Post Tc Subcatchment 7S: Untreated DA #2 Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ❑Runoff 1.23 cfs Type W24-hr -- 2Tvr_R'ai nfail l 3.56" 1 R0n6ffAwea=3.700 at RL;npff',VQ1L;me=',7,48$ pf R61n off ' De pth TO.'561' LL Tc=30.0 Mid GN=6b 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 213: BMP Treated DA Runoff = 10.70 cfs @ 11.96 hrs, Volume= 23,044 cf, Depth= 4.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.20" Area (ac) CN Description 1.140 98 Impervious 0.000 60 Woods 0.380 69 Grass 1.520 91 Weighted Average 0.380 25.00% Pervious Area 1.140 75.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph I I I I I I I I I I I I I I I I I I I I I I I ■Runoff 11 10.70 cfs--t--t--r--I---I---I--y--rt--rt--�--r--r--I---I--�--�--t--r--r- -- ------1--L----1---1---1--J--1--1----L--L------Typq-142-4-k�r - 10 ---- -- -- - ------ -- -- -- 0-yr-k-aF'Infal1=15.20I -- I I I I I I I I I I I I I I 9 I I I I I I I I I I I I I I I I I I I I I I ' -- - ------------ -- -- +-R-urwff Area=-I.-52-0-ac-- $ -'I-- --'I----t--t--r--------'I-- --rt-- R nr�f 'WALtIn6=23,044-d - _ 7 ' 0 6 - -- -- - - -----------Vic'=-Sf0-a- LL 5 -------- - - ------- - - - - -- - iN=_91-- 4- 3- 2 1 I I I I I I I I I I I I I I I I I I I I I I 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 11 Summary for Link 3A: P0I#2 Inflow Area = 479,160 sf, 21.00% Impervious, Inflow Depth = 2.30" for 10-yr event Inflow = 18.15 cfs @ 12.19 hrs, Volume= 91,992 cf Primary = 18.15 cfs @ 12.19 hrs, Volume= 91,992 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 3A: P0I#2 Hyd rog raph ' --1--J--J--L--'---'--J--L--'---'--J--L--L--'--J--J--L--'-----J--J--J--'-- i ------- --L-------J--L-- ---- --+-- -------+-- -- ---- ■Inflow 20 19 18.15 cfs +--I---I--+--+--I---I--+--+--+--I--+--+--+--I---I--+--r--+--I-- --r--r--I--r--r--r--I--r- r- lln Ar �� e �_ UG 4 9 s- f ■Primary 18 I � 7 I +--rr--I-- I I 17 ,i - - - - - - - - - - - 16 -J--J--'---'--J--L--'---'--J--L--J----J--J--J-------J--J--J--'-- 15 -------'-- --L-------J--L-- --'-- --+-- -------+-- -- --'-- 14 -- +--+--+-+--+--+--+-+--+--+--+--+-+--+--+----+--+--+--+-+-- 13 -- 7--r--li---li-- --r--Ir--li-- --r--Ir--li--7--7--Ir--Ir--li--7--r--Ir--li-- 12 - - I I I - I I I - - I I I I - - I I I I - - - I I I I I - I I y 3 10 J--L--1---1--J--L--'---'--J--L--J--1--J--J--J--1---1--J--J--J--'-- a 9 -- +--------- --L-------J--L-- ---- --+-- -------+-- -- ---- $ -- +--r---------+---------+--+------+--+-------+--r--+--I-- 7 --I-- 6 4 3 -- ------'-- --L-------J--L-- --'-- --+-- -------+-- -- --'-- 2 1 .0 65 70 75 :0 85 90 95 100 Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 12 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 75.00% Impervious, Inflow Depth = 4.18" for 10-yr event Inflow = 10.70 cfs @ 11.96 hrs, Volume= 23,044 cf Outflow = 0.92 cfs @ 12.43 hrs, Volume= 23,044 cf, Atten= 91 %, Lag= 28.2 min Primary = 0.92 cfs @ 12.43 hrs, Volume= 23,044 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 634.96' @ 12.43 hrs Surf.Area= 5,393 sf Storage= 13,393 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 1,050.6 min calculated for 23,038 cf (100% of inflow) Center -of -Mass det. time= 1,051.6 min ( 1,832.9 - 781.3 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 13 Primary OutFlow Max=0.92 cfs @ 12.43 hrs HW=634.96' (Free Discharge) L1=Outlet (Passes 0.92 cfs of 20.16 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.06 cfs) 3=Low Flow Orifice (Orifice Controls 0.04 cfs @ 7.18 fps) 4=Grate Top ( Controls 0.00 cfs) =Weir 1 ( Controls 0.00 cfs) =Weir 2 (Orifice Controls 0.82 cfs @ 2.73 fps) Pond 313: Sand Filter Detention Pond Hyd rog raph 10.70 cfs-r-------;--r-------,--t--Ir---��--art--Ir----- --4-4-4-T- 11 --I---rt--r--+--li----r--Ir----y--+-intlViY Areo=-66,2i11l-Sf- 10 --I---+--+--+-+--+--+--+----+--+--+--I- + 1 - -Pea� E rw=614-96 9 --II---�--�--II---II--�--�--II---II--�--�--I --II- �--�--II__ I �I torage=l 3�1 d 8 - --II---1--L-----II-- --L-------J--i--IL----J--1--L--1-----1--L--L--I-- I I I I I I I I I I I I I I I I I I I I I I 3 6 --I-- -+--T-----I-- T--i--T-------i--T-------+--T-------+--T --T --I-- 0 I LL 5 it I I I I I I I I I I I I I I I I I I I I I I Q --I-- -T--T--I---I--T--T--I --__T--T__T--I__T__+--T-------T--T--T--I-- 3 --I-- ---r-----I----r-------1--r--Ir----I--7--Ir-----I----r--Ir--I-- ,' I I I I I I I I I I I I I I I I I I I I I I I 2 --- +--r--I---I--+--+--I---I--+--+--+--I--+--+--+--I---I--+--r--+--I-- 0.92 cfs 1 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) ❑ Inflow ❑ Primary Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 14 Summary for Subcatchment 4S: Untreated DA #1 Runoff = 9.75 cfs @ 12.18 hrs, Volume= 35,562 cf, Depth= 2.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.20" Area (ac) CN Description 1.150 69 Grass 1.430 60 Woods 1.170 98 Impervious 3.750 75 Weighted Average 2.580 68.80% Pervious Area 1.170 31.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.0 Direct Entry, Post Tc Subcatchment 4S: Untreated DA #1 Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ■Runoff ---- -- -- - - -- -- --+--,---------Typ�a12-1K - --'�-- Runoff area=3.750 aic 7 RUndff IVdluwn6=35,562 Cf 6 Runoff Depth-2.611" --r--i--r--r--r--r--r--r--i--r--r--r--r--r--r--r--i--r-- - r- r--r-- 0 5 T�= 47 M i p 4 N=7 - - 3 2 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 15 Summary for Link 5L: POI #1 Inflow Area = 229,561 sf, 43.83% Impervious, Inflow Depth = 3.06" for 10-yr event Inflow = 10.61 cfs @ 12.18 hrs, Volume= 58,606 cf Primary = 10.61 cfs @ 12.18 hrs, Volume= 58,606 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 5L: POI #1 Hyd rog raph -----'------------------------'----------'----------'-- ■ Inflow ❑ Primary 11 10.61 cfs-if?f�OP=29;rJ�i S;- 10 --i-T--r-----i-- --r--i --i-- --r-- --i-- --T---------T--r-- --li-- 9 --1-rt--r--r--1--�--r--r--1--y--+--r--r-y--+--r--1---1--rt--r--r--1-- 8- 7- L--L--'--- '--L--L--1---1--J--1--L--1--J--1--L--1-----L--L--L--'-- y I I I I I I I I I I I I I I I I I I I I I U I I I I I I I I I I I I I I I I I I I I I 6LL__1___1__J__L__L__1__ J__ L__ L__1___1__ L__ L__ L__1__ 3 I I I I I I I I I I I I I I I I I I I I I p a 5 4 I I I I I I I I I I I I I I I I I 1 - -- --i-----i-- --i-----i-- --i-----i-- -- --i --i-- 3 , --1---r---Tr r1rrr-Tr1TrTr-Tr-11Tr-r1 -T 2 --r--r---r-- 10 r----11--- - AM 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 16 Summary for Subcatchment 6S: Bypass Ditch DA Runoff = 3.90 cfs @ 12.17 hrs, Volume= 14,323 cf, Depth= 1.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.20" Area (ac) CN Description 0.000 98 Impervious 0.450 60 Woods 1.580 69 Grass 2.030 67 Weighted Average 2.030 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 Direct Entry, Post Tc Subcatchment 6S: Bypass Ditch DA Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ■Runoff 3.90 cfs-�--�--�--�---;---;--�--�--�--�--�--;---;---;--�--�--�--�---;---;- 4 T Yp� II' 24- 'r 1 10-ir kai,nfall=5.,201" -- -'-- -- ----------'-- ----+--r--' Runoff Are'a='2.030-a-c- 3 Rhn6ffM61uwn6=14,323 cf w Runoff Dept h=1.';94;" --r- r--r--r--r--r--r--i--r--r--r--r--r--r--i--r--r--r-- i- i -i-- 2 LL T�= 3f0 �T1ip 4N=6� --I -1-- 1 I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) 25-Year Routing Page 111 of 140 Carolina Pet Post Type/1 24-hr 10-yr Rainfall=5.20" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 17 Summary for Subcatchment 7S: Untreated DA #2 Runoff = 4.04 cfs @ 12.27 hrs, Volume= 19,064 cf, Depth= 1.42" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 10-yr Rainfall=5.20" Area (ac) CN Description 0.000 98 Impervious 3.560 60 Woods 0.140 69 Grass 3.700 60 Weighted Average 3.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Post Tc Subcatchment 7S: Untreated DA #2 Hydrograph I I I I I I I I I I I I I I I I I I I I I I I ■Runoff 4.04 cfs 4 Ty/pq II'I 24-hr 10*r Fkailnfall=5.'1201�� -- -I----rt--r-----I-----rt--t-----',Runoff Area=3J00-a�c- 3 RhndffMoluwnc=19,064 cf w Runoff Dept h=1.',421," I I I I I I I I I I I I I I I I I I _ -I-- -- - - ------I-- -- - ---------=�i�f0 �1lll ° 2 LL I 4N=6p 1 I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 18 Summary for Subcatchment 213: BMP Treated DA Runoff = 13.04 cfs @ 11.96 hrs, Volume= 28,487 cf, Depth= 5.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.21" Area (ac) CN Description 1.140 98 Impervious 0.000 60 Woods 0.380 69 Grass 1.520 91 Weighted Average 0.380 25.00% Pervious Area 1.140 75.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph I I I I I I I I I I I I I I I I I I I I ■ Runoff 14 13.04 cfs -- -- ------------ -- -- -- --r--------- „--I+--r-h-- 13 T ------T--T- -T-----------T--T--T--T--F T -----r ype-1k24 1-r - --'-- --'----1--L----1---1---1--J--1--1--+--L 12 11 I I I I I I I I I I I I I I I I I I I I I -- - -- -- - - - -- --4 -- -- -Runoff Area= F.-520-ac-- 10 9 RUnd Vdluwn�=2$,FB�C - Runoff Depth=5• ''16"' --I--------+--+--------------+--+--+--+----I-----+-`�--+--+--�-- LL 7- 0 - -- -- - - -- -- - - -----------Vic'=-5TO-ni- 6 s 4 ---- ---- -------------------1-- --------------- - ----- -------I--- 3 2 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 19 Summary for Link 3A: P0I#2 Inflow Area = 479,160 sf, 21.00% Impervious, Inflow Depth = 3.08" for 25-yr event Inflow = 26.54 cfs @ 12.18 hrs, Volume= 123,099 cf Primary = 26.54 cfs @ 12.18 hrs, Volume= 123,099 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 3A: P0I#2 Hyd rog raph r--li-li--------li-liy--+--Ir--liy--+--Ir--li---li--rt--r--Ir- -li-- ■ Inflow ❑ Primary ------ - - lgfjoW1 Arej=479,1-60-s;f_ - 00 105 110 115 120 Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 20 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 75.00% Impervious, Inflow Depth = 5.16" for 25-yr event Inflow = 13.04 cfs @ 11.96 hrs, Volume= 28,487 cf Outflow = 3.67 cfs @ 12.08 hrs, Volume= 28,487 cf, Atten= 72%, Lag= 7.7 min Primary = 3.67 cfs @ 12.08 hrs, Volume= 28,487 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 635.33' @ 12.08 hrs Surf.Area= 5,724 sf Storage= 15,433 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 872.7 min calculated for 28,487 cf (100% of inflow) Center -of -Mass det. time= 872.6 min ( 1,648.3 - 775.7 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 21 Primary OutFlow Max=3.60 cfs @ 12.08 hrs HW=635.33' (Free Discharge) L1=Outlet (Passes 3.60 cfs of 20.81 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.07 cfs) 3=Low Flow Orifice (Orifice Controls 0.04 cfs @ 7.75 fps) 4=Grate Top ( Controls 0.00 cfs) =Weir 1 (Weir Controls 2.28 cfs @ 1.19 fps) =Weir 2 (Orifice Controls 1.22 cfs @ 4.05 fps) Pond 313: Sand Filter Detention Pond Hyd rog raph ❑ Inflow 14 13.04 cfs-r----------r-----I----fi--Ir--I----7--Ir-------rt--r--Ir--I-- ❑ Primary 13 --I-- - 'I --------- 'I -- -- -----I-- --Mn low'llAreo=61"i,,211l, sf - 12 10 --I---+--+-------+--+-------+--+--+---Blom �16,433-Gf - 9 --I-- - II --T--I---I-- II--r--T--I---I-- i --T--I----- I ---------- I --i------- N --I---1____-----__L-------__L--__-- --+-----1---1--1-------I-- '� 8 p I I I I I I I I I I I I I I I I I I I I I I LL 6 5 T--r--r--1--7 r-- r-T--T--r-------T--r--r--I-- i a 3.67 cfs ---- -- ---- ------ ---- -- -- 3 ---t-- r--r--I-- --r--r-------+--r-------+--r-------rt--r--r--I-- __I---I-- 2 1 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 22 Summary for Subcatchment 4S: Untreated DA #1 Runoff = 12.96 cfs @ 12.17 hrs, Volume= 47,123 cf, Depth= 3.46" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.21" Area (ac) CN Description 1.150 69 Grass 1.430 60 Woods 1.170 98 Impervious 3.750 75 Weighted Average 2.580 68.80% Pervious Area 1.170 31.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.0 Direct Entry, Post Tc Subcatchment 4S: Untreated DA #1 Hydrograph ■ Runoff 14 12.96 cfs,--7--r--r-------------------t--r--'r--I--------,-----r- 'r-- 13 -----------------------------------------------Typ�1k24 1 - 12 1 1 -- -----1--L--L--1---1---1--J--1--L-- --L2-y,r-ka"nf 1 1=&.;21`'-- --i---i--r--r--r--r--r--r--i--r--r--r- r- 10 - FZurvoff A rera=r3. 7, 5-0 arc- - 9 RUn6ff Vdluwn6=47,123 C - Runoff Depfh "3.'46" r----y--+--t--r--r-------y--rt--rt--+- r--r-------y--+--r--r-- 7 -- -- - -- -- -- - -------------4fi0-�- 6 --'---'--�--1--L--L--1---1---1--J--1--1--�--L--L--'---'--J--L- 1�1�7 - 5 --r- ---- ----t----r----r------------y----rt----rt----+----r----r--------------------+ - i----i i---- - - ----Tr- 3 I I I ---L-L--1-----L -LL-L-LLL-L-- -L 2 r----- - 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 23 Summary for Link 5L: POI #1 Inflow Area = 229,561 sf, 43.83% Impervious, Inflow Depth = 3.95" for 25-yr event Inflow = 15.62 cfs @ 12.14 hrs, Volume= 75,609 cf Primary = 15.62 cfs @ 12.14 hrs, Volume= 75,609 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 5L: POI #1 Hyd rog raph --I--�--�--T--I---I--�--T--�--I--�--T--�--I--T--T--�--I---I--�--T--�--I-- ■ Inflow r--I---I--+--+--I---I--+--+--r--I--+--+--r--I---I--+--r--r--I-- � Prima 17 � Primary 15.62 cfs -- -----I-- -- -----I-- -- -1�Ilfro�- Ikr- � 6,61' SI`� 16 - -- -----I-- -- -----I-- -- -- --T-- +--�--�- -- --I-- 15 - L--L-------L-- L-------J-- L--L--I - -J -- L--L--I---I--L--L--+--I-- 14 13 12 - -- -----I-- -- --i-----I-- --i-----I-- --i-----I-- -- --i --I-- 11--i---------r--i-------r--i---------i---------i --i --I-- __ --I-_r__Y__r__I___I__Y__r__r--I-- w 10 �I 3 -- L--L--I---I--L--L--I---I--L--+--L--I--�--+--L--I---I--L--L--L--I-- o g LL __ LL_______L__L_______J__L__L__I__J__1__L__I___I__1__L__L__I__ 7 6 5 4 3 �I I I I I I I I I I I I I I I I I I I I I I I -- --r-------r--r--r----r--r--r----r--Y--r-------Y--r--r-- I -- 2 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 24 Summary for Subcatchment 6S: Bypass Ditch DA Runoff = 5.51 cfs @ 12.17 hrs, Volume= 19,819 cf, Depth= 2.69" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.21" Area (ac) CN Description 0.000 98 Impervious 0.450 60 Woods 1.580 69 Grass 2.030 67 Weighted Average 2.030 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 Direct Entry, Post Tc Subcatchment 6S: Bypass Ditch DA Hydrograph ----------T--- -r-----I----- T-- T-- T --T------------T--T----------I-- 6 ❑Runoff 5.51 cfs 5 25-y11i kaill,nfall=6.111211" Runoff arena=12.030 aic --I-- -I-- -- -- ---------I-- -- -- -------- --- -------------- --- -- 4 Rhndff M61uwnc=19,819 cf Runoff DQ`{p h=2.'169`' T - - T - - - - - - - - - T - - T - - T - - T - - - - - - - - - -I T - - - I I - - 3 Tq=3f0 Fn i 2 --I----------------------------------------------------I-_ 1 I I I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) 50-Year Routing Page 121 of 140 Carolina Pet Post Type // 24-hr 25-yr Rainfall=6.21 " Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 25 Summary for Subcatchment 7S: Untreated DA #2 Runoff = 6.18 cfs @ 12.26 hrs, Volume= 27,671 cf, Depth= 2.06" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 25-yr Rainfall=6.21" Area (ac) CN Description 0.000 98 Impervious 3.560 60 Woods 0.140 69 Grass 3.700 60 Weighted Average 3.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Post Tc Subcatchment 7S: Untreated DA #2 Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ■Runoff 6.18 cfs 6 ---- --- -- -- --il-------r-- -- ----r--r-----i- Tr--r-II 24- -i�- YPO ------- ------------2 Y,rFkai,nfaIl=6.,211" 5 Runoff area=3.700 aic -- --- -- ------------ ----1--RUn6ff-V-b u =273671-cf- N 4 Runoff Depih=2.';OV I I I I I I I I I I I I I 3 --'-- ---;----r--------'-- ----T--r--'--------'--7 Tp=flfflrr�ip- 0 a 3 - ---------------------- -- -- -- -- -- -- 4N=60 z 'I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 26 Summary for Subcatchment 213: BMP Treated DA Runoff = 14.90 cfs @ 11.96 hrs, Volume= 32,876 cf, Depth= 5.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 50-yr Rainfall=7.02" Area (ac) CN Description 1.140 98 Impervious 0.000 60 Woods 0.380 69 Grass 1.520 91 Weighted Average 0.380 25.00% Pervious Area 1.140 75.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph I I I I I I I I I I I I I I I I I I I I ■ Runoff 16 14.90 cfs ;-- T - -T-- --'---------T--T--T--T--'F--I - - - -- ---1 T--T--'F-- 15 T I�' 2y_ 14 --'-- --'----1--L--'--1---1---1--J--1--1--+--' -'--- - 13 I =ylr F ailnf�ll=7. 21" /a ------------------------------------------------/-�,----------- - ----- 12 - Runoff rea=,1 520 -a c-- --+- -+--+--+--+--+--+--I--+--+--+--+--+ 11 ---- - -- --------------- '--- Rtinbff'IV61Ltwn6=3Z,&76-df- 10 9 Runoff -Deph=5.96"' - 1--4--4--+--I----1---I-`+ - - I -- I I I cI 51fo -------J 7 �- 6 5 Q - - - - - - - - - - - - - - - - - - I- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3 2 1 I I I I I I I I I I I I I I I I I I I I 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 27 Summary for Link 3A: P0I#2 Inflow Area = 479,160 sf, 21.00% Impervious, Inflow Depth = 3.74" for 50-yr event Inflow = 32.91 cfs @ 12.17 hrs, Volume= 149,246 cf Primary = 32.91 cfs @ 12.17 hrs, Volume= 149,246 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 3A: P0I#2 Hyd rog raph ■ Inflow 32.91 cfs 1-----1-- -------1---1--------------- ------ -- ------ ■ Primary I I I I I I I I I I I I I -- - - - J11nflo�r Area=47-9.11�6Qsf_ 32 'I -- _T--r I 1 1 I _T - I 1 -F 1 1 I 30 1 T--T I T T 1 T- T r T--1-- 28 �1 26 �1 --1 TrT--1-- 24 1 -- �--r--r--1--�--r--1---1--�--r--r--r-r--r--r--1---1--�--r--r--1-- 22 __ r--r--1---1--r--r--r--1--r--r--r--1--r--r--r--1---1--r--r--r--1-- --I__�__T__�__I--T--T--T--I---I--T--T--T--I-- y u 20 T--T--I---I--T--T--I 1 r--r--1---1--r--r--r--1--r--r--r--1--r--r--r--1---1--r--r--r--1-- 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 18 1 p LL 16 -- r--r--r--1--r--r--r--1--r--r--r--r-r--r--r--1---1--r--r--r--1-- 14 r--r--r--1--r--r--r--1--r--r--r--r-r--r--r--1---1--r--r--r--1-- 12 10 8 6 n 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 28 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 75.00% Impervious, Inflow Depth = 5.96" for 50-yr event Inflow = 14.90 cfs @ 11.96 hrs, Volume= 32,876 cf Outflow = 8.99 cfs @ 12.04 hrs, Volume= 32,876 cf, Atten= 40%, Lag= 4.7 min Primary = 8.99 cfs @ 12.04 hrs, Volume= 32,876 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 635.49' @ 12.04 hrs Surf.Area= 5,867 sf Storage= 16,314 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 766.9 min calculated for 32,868 cf (100% of inflow) Center -of -Mass det. time= 767.9 min ( 1,539.9 - 771.9 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 29 Primary OutFlow Max=8.78 cfs @ 12.04 hrs HW=635.49' (Free Discharge) L1=Outlet (Passes 8.78 cfs of 21.08 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.07 cfs) 3=Low Flow Orifice (Orifice Controls 0.04 cfs @ 7.98 fps) 4=Grate Top ( Controls 0.00 cfs) =Weir 1 (Weir Controls 7.31 cfs @ 1.76 fps) =Weir 2 (Orifice Controls 1.35 cfs @ 4.49 fps) Pond 313: Sand Filter Detention Pond Hyd rog raph 14.90 cfsI 16 -- ---1' --r---------r---------r10— ��,2,1-1S_ 15 14- 13 I 12 --,-- -?--,I-----,-- ,--,I--,I---,---,-- II--,I--1,-8#hQral"I =II1 VI,3II1y� 4111 CI - 11 --I-- --r T---r--i --I----+--r-- �- -+-- --I--+ - r--F - -I-- +--r-------+--+-------+--+--+----+--+--+-------+--r--+--I-- 10 8.99 cfs N U 9 I I I I I I I I I I I I I I I I I I I I I 3 $ I I I I I I I I I I I I I I I I I I I I I O i i I I I I I I I I I I I I I I I I I I I I I I I --+-------7--+--r--I__7__Y--r--I___I--+--Y--r--I-- 6 i --I -1--L--I---I--1--+--I---I--J--1--L--I--J--1--L--I---I--1--L--L--I-- 5 4 ----r-----Ii----r--Ii --Ii----r--Ir----T--T--1 -------7--r--Ir---- 2 �I 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) ❑ Inflow ❑ Primary Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 30 Summary for Subcatchment 4S: Untreated DA #1 Runoff = 15.60 cfs @ 12.17 hrs, Volume= 56,724 cf, Depth= 4.17" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 50-yr Rainfall=7.02" Area (ac) CN Description 1.150 69 Grass 1.430 60 Woods 1.170 98 Impervious 3.750 75 Weighted Average 2.580 68.80% Pervious Area 1.170 31.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.0 Direct Entry, Post Tc Subcatchment 4S: Untreated DA #1 Hydrograph 17 ■Runoff 15.601 cfs ,--,--, - + 16 ---- -----1--L------------�I-- -- --; --;--IL------T p 1f24=hr - 1s 14 ---- --- 1--1--, --,-----------1--1--1----r0-yr-�a'1nf�d1=7.D21"-- 13 1 1 1 1 1 1 -- -- -- - - --r-- -- -- Rurtoff area=3.-75ii ac-- 12 --I-- -I-- --+-- -- --------I-- -- -- --+-- ---------+-- --+-- -- -- 11 - - - - - RUnbff'1V61ul r6_=_56,724 d - w 10 --I-- -I-- -- -- 1 1 1 1 1 --I-----------I-- -- ----1IIFRU-nOff-Depfh=4.j 77 '-- V 9 1 1 1 1 1 1 1 1 o $ - ---1--,--7--r--r-------------------t--r--r--1---1-T 4$0- r -- LL --11-- -- -- -- ----I---11I-------4--I--I--I--'I--11---11-- 7 6 5 - - - - - - - Q --r- -1--r--r--r--r--r--1---1--r--r--r--r--r--r--1---1--r--r--t--r--r-- 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 31 Summary for Link 5L: POI #1 Inflow Area = 229,561 sf, 43.83% Impervious, Inflow Depth = 4.68" for 50-yr event Inflow = 20.33 cfs @ 12.06 hrs, Volume= 89,600 cf Primary = 20.33 cfs @ 12.06 hrs, Volume= 89,600 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 5L: POI #1 Hyd rog raph -------- -- ---------- -------------------- -- --- 11 ■Inflow 22 21 2033 cfs -L--1---1--L--L-----'-- --r--r--i--r--r--r--i--r--r- --L--L--1--J--L-- ll �W A --1---1--L--L--+--'-- r rep=�29, 5611, sf ■ Primary .nf 20 - -- -- - -- -- -,-- - -; - 19 -- - -------'-- -- -----'-- -- -- --'-- --+-- -----'-- -- -- --'-- 18 -- - --r------- --r-------1--r--Ir----I--7--r----------r--r---- 17 -- ----------------------------------------------------------- 16 -- - --------- -- ------- -- -- ---- --+-- ------- -- -- ---- 15 14 - - - - - - - - - - - - - w 13 12 -- +--+--+-+--+--+--+-+--+--+--+--+-+--+--+----+--+--+--+-+-- a 10 -- L--L--'---'--L--L--'---'--J--L--L--'--J--+--L--'-----L--L--+--'-- rt--r--Ir--li- -- --r --Ir--li--y--+--Ir--Ir -y--+--Ir--li- --li--rt--r--Ir--li-- 9 ------- -- -- ---- -- -- ---- -- -- ------- -- -- ---- 8 -- L--L--'---'--L--L--'---'--J--1--L----J--L--L-------L--L--L--'-- 7 -- --r------- --r------- --r--r---- --7--r------- --r--r---- 6 -- ---- -- ------ ----- ---------------------------------------- - 4 -- 7--r------- --r-- ------r--r---- --T--r-------7--r--r---- 3 -- - - - - - - - - - - - - - 1 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 32 Summary for Subcatchment 6S: Bypass Ditch DA Runoff = 6.86 cfs @ 12.17 hrs, Volume= 24,486 cf, Depth= 3.32" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 50-yr Rainfall=7.02" Area (ac) CN Description 0.000 98 Impervious 0.450 60 Woods 1.580 69 Grass 2.030 67 Weighted Average 2.030 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 Direct Entry, Post Tc Subcatchment 6S: Bypass Ditch DA Hydrograph � � � � � � � � � � � � � � � � � � � � � � � ■Runoff 6.86 cfs - -- ------------ -- -- -- --------- - - - - -- ----- - - - - -- 7- Typq II' 24- 'r '� --�-- -�-- �-- � -- �--�---�---�---�-- � -- � -- �--�---�-5�=y�,r l�ai�-nf��f 6 =7:�,0��'- 'I Runoff Are�'a=�2.030 aic 5-Runoff M61uwnc=24,486 cf N - -- -- -- -- -- -- -- -- '1funoff Depth=, 3.;32"- 3 Tq=210 In i p 0 LL I --I-- -I--I--I--I--I---I---I---I--I--I--I--I---I---I---I--------------- ---- 3 (N=16y ---- --- ;--;------------- -,--;--;---------------- ---------------- 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) 100-Year Routing Page 131 of 140 Carolina Pet Post Type 11 24-hr 50-yr Rainfall=7.02" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 33 Summary for Subcatchment 7S: Untreated DA #2 Runoff = 8.04 cfs @ 12.26 hrs, Volume= 35,159 cf, Depth= 2.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 50-yr Rainfall=7.02" Area (ac) CN Description 0.000 98 Impervious 3.560 60 Woods 0.140 69 Grass 3.700 60 Weighted Average 3.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Post Tc Subcatchment 7S: Untreated DA #2 Hydrograph 9 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ■Runoff 8.04 cfs - -- -- --------II-- -- -- -- --I --------------------------I- 8 Ty/pg IIIII 24-hr 7 --II, - -I Runoff area=17-Oaac- 6 Rhndff Vduwnd=35,158 cf 5 Runoff Depth=2.621" 3LL0 T 00 4 _I ll1l N -I-- -- ------- -I-- -- -- ------I-- -- -• 3 2 1 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 34 Summary for Subcatchment 213: BMP Treated DA Runoff = 16.85 cfs @ 11.96 hrs, Volume= 37,498 cf, Depth= 6.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=7.87" Area (ac) CN Description 1.140 98 Impervious 0.000 60 Woods 0.380 69 Grass 1.520 91 Weighted Average 0.380 25.00% Pervious Area 1.140 75.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Post Tc Subcatchment 213: BMP Treated DA Hydrograph --------'- - -- -- ------------------------------------ - -----------I ■Runoff 18 16 yp� � - -- -T-- T--T--��------- --T--15 --T-- 71 ka ,8 71, 14 --� -- -- 13 --r---i--r--r---r--r--r--i---i----,r---- r---- rt---- r-R-ru--rVrof-fi- a--ir-e-ar-=-r4-.--5r2--0ra--rc--- - ww-� 12 ------r--- ---i------TT--TT-- --+--+--+F-F---u-l-n-6+=-37-C-,+4 -9-8+'--c-f+-- 11 ----T--T-- --T--T--T---R'nofif De 1h`-fi.00rr- - -- I I10 -I -+- + - +-+ 0 9----+--+--+--+----------+--+--+--+--+--+-------+c=�+O- i a 8 7 --'-- --'----1--L--r--1---1---1--J--1--1--i--L--+-------J--1-- --L-- -- 6 5 ---- -------------------------------------------------------------- 4 2 ---- ----------------------i-- --------------------- i----r--i--- 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 35 Summary for Link 3A: P0I#2 Inflow Area = 479,160 sf, 21.00% Impervious, Inflow Depth = 4.45" for 100-yr event Inflow = 39.52 cfs @ 12.17 hrs, Volume= 177,574 cf Primary = 39.52 cfs @ 12.17 hrs, Volume= 177,574 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 3A: P0I#2 Hyd rog raph ----------, -----I-- -- + --------I-- + --, -----I-- --, -----I-- --, --, --I-- ■ Inflow 44 L-----'----L--1---1--J--1--L--1--J--L--L-------L--L--L--'-- ■ Primary 42 40 39.52 cfs--r-----I-- ---- + + 38 - - - - - - - - - - - - - - 36 -- - -----------+------- --+-- ---- --+--------- -- -- ---- 34 -- -T-- T-------T- -T -- ------T--F-----1 T--F-------T--T--r----- 32 - - - - - - - - - - - - - 30 --' -------'----+-----'-- --+-- --'-- --+-------'-- -- -- --'-- 28 26 - - - - - - - - - - - - - u 24 -- -------'----+-----'-- --+-- --'-- --+-------'-- -- -- --'-- 3 22 -- 7--r-------,--r---------t--r---- --T--r-------7--r--r---- 0 20 LL - - - - - - - - - - - - - 18 - L--L-----'-- --L--'---'--J--L--L----J--L--L-------L--L--L--'-- 16 -- rt--r--Ir--li----r--Ir--li----r--Ir--Ir- --T--Ir--li---li--rt--r--Ir--li-- 14 -- +-- - - - I -- --;-- - - -I -- +-- - - - I -- + 12 -- L--L--'---'--L--L--'---'--J--L--L--'--J--+--L--'-----L--L--L--'-- 10 -- +--+--+-+--+--+--+-+--+--+--+--+-+--+--+----+--+--+--+-+-- 8 + + 6 -- --L--1---1--L--L--'---'--J--L--L--1--J--L--L--1---1--L--L--L--'-- 4 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 36 Summary for Pond 313: Sand Filter Detention Pond Inflow Area = 66,211 sf, 75.00% Impervious, Inflow Depth = 6.80" for 100-yr event Inflow = 16.85 cfs @ 11.96 hrs, Volume= 37,498 cf Outflow = 13.48 cfs @ 12.01 hrs, Volume= 37,498 cf, Atten= 20%, Lag= 3.1 min Primary = 13.48 cfs @ 12.01 hrs, Volume= 37,498 cf Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Peak Elev= 635.60' @ 12.01 hrs Surf.Area= 5,962 sf Storage= 16,899 cf Flood Elev= 636.00' Surf.Area= 6,337 sf Storage= 19,377 cf Plug -Flow detention time= 682.9 min calculated for 37,498 cf (100% of inflow) Center -of -Mass det. time= 682.8 min ( 1,451.4 - 768.6 ) Volume Invert Avail.Storage Storage Description #1 631.10' 19,997 cf Detention (Prismatic) Listed below Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic -feet) (cubic -feet) 631.10 0 0 0 631.60 1,566 392 392 632.60 3,447 2,507 2,898 633.60 4,229 3,838 6,736 634.60 5,067 4,648 11,384 635.60 5,962 5,515 16,899 636.10 6,431 3,098 19,997 Device Routing Invert Outlet Devices #1 Primary 628.60' 18.0" Round Outlet L= 36.0' Ke= 0.500 Inlet / Outlet Invert= 628.60' / 628.15' S= 0.0125 '/' Cc= 0.900 n= 0.013, Flow Area= 1.77 sf #2 Device 1 631.10' Sand Bed Exfiltration Elev. (feet) 631.10 631.60 632.60 633.60 634.60 635.60 636.10 Disch. (cfs) 0.000 0.024 0.035 0.047 0.059 0.071 0.077 #3 Device 1 632.70' 1.0" Vert. Low Flow Orifice C= 0.600 #4 Device 1 635.60' 1.0" x 1.0" Horiz. Grate Top X 16.00 columns X 16 rows C= 0.600 in 48.0" x 48.0" Grate (11 % open area) Limited to weir flow at low heads #5 Device 1 635.20' Weir 1 X 4.00, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.40 Width (feet) 3.60 3.60 #6 Device 1 634.50' Weir 2, Cv= 2.62 (C= 3.28) Head (feet) 0.00 0.30 Width (feet) 1.00 1.00 Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 37 Primary OutFlow Max=13.10 cfs @ 12.01 hrs HW=635.59' (Free Discharge) L1=Outlet (Passes 13.10 cfs of 21.26 cfs potential flow) 2=Sand Bed Exfiltration (Custom Controls 0.07 cfs) 3=Low Flow Orifice (Orifice Controls 0.04 cfs @ 8.13 fps) 4=Grate Top ( Controls 0.00 cfs) =Weir 1 (Weir Controls 11.55 cfs @ 2.05 fps) =Weir 2 (Orifice Controls 1.43 cfs @ 4.76 fps) Pond 313: Sand Filter Detention Pond Hyd rog raph 16.85 cfs -- -- - - - ------------------ 18 17 ---- -------------------,---,--,---�nf;1�,wl',Are�i=6G,21-1'�,-S# 1 15 --'-- - --'------- --' --'-----'--'------�e6lR �feV=$8-5.6-'' - � � 14 13.48 cfs --------------------------------------------------------- -- - --- ------ tor 1 =116,-899� ef 13-1--L--1---'-- --+--'---'--J--+--L----J--1--L--1-----1--L--L--'-- 12 _ 10 0 9 --1--L--1---'-- --+--'---'--J--+--L----J--1--L--1-----1--L--L--'-- a 8 7 - -------i----+-----i-- --+-- --i-- --+-------i-- -- -- --i-- 6 - -----------+------- --+-- ---- -- --------- -- -- ---- 5 - ------------ +------- -- -- +- --- - - -- --+-- -----------------i-- 3 2 -- 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) ❑ Inflow ❑ Primary Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 38 Summary for Subcatchment 4S: Untreated DA #1 Runoff = 18.41 cfs @ 12.17 hrs, Volume= 67,035 cf, Depth= 4.92" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=7.87" Area (ac) CN Description 1.150 69 Grass 1.430 60 Woods 1.170 98 Impervious 3.750 75 Weighted Average 2.580 68.80% Pervious Area 1.170 31.20% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 24.0 Direct Entry, Post Tc Subcatchment 4S: Untreated DA #1 Hydrograph --r--I---I--r--r--r--r--r--I---I--r--r--r--r--r--r--I---I--r--r--t--r--r-- 20 ■Runoff 19 18.41 cfs--7--r--�--�---�---�--�--�--�--r--r--�--�---�--,--,--T--r--�-- 18 -'- '- '------------------- ----------------��I-Type 1124-k1 ---- -I-- -------------------I-- I I I I I I I I I I I -- I -I -I 1�I=yr=Fai��nfil-1 =7-.8- 71r=-� 16 -- I I I I I I I 15 --�-- --- -- -- ------------ -- ----�Rurtoflf Area=3.-75-0ac-- 14 ---- ---+--+--+--+----------+--+--+--+--+--+--1-----+--+--+--+--+-- f IV61uhi6=67,035-c# - 12 - -I- - -I r - - Y - r - - r - - - - - - - - - - r - - r - - r - - I I I I- I I u 11 1 F�unof-Depht4.32' -- -I-----1--7--T--r----------1--7--T- T- T- r -I -I - 1 0 10 --'I-------t---------------------t---------------T"-4f0-jy�ip in-- a9 ---- --- -- -- --------------- -- -- ---------------------1-•-•- 8 --'---'-----------------------------------------'-- I'- ���--- I I I I I I I I I I I I I I I I I I I I 7 --'-- -'--!--!--!--!--'---'---'---'--!--!--!--!--'---'---'---'--!--!--!--'--- I I I I I I I I I I I I I I I I I I I I I I 6 ---- --- -- -- ------------ -- -- -- -- --------- -- -- -- -- -- 5 --i-- -i--+--+--+--+--i---i---i--+--+--+--+--+--+--i---i--+--+--+--+--+-- 4 j --'r---- t-- t-- t-- t-- --------t--t--t--t--t--t-------t----+--t--t-- 3 --'r- ---t--t--t--t----------t--t--t--t--t--t-------t--t--t--t--t-- 2 --'I------t--i --i --i------------t--i --i --i------------t--II --'i -- I I I I I I I I I I I I I I I I I I I I 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 1 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 39 Summary for Link 5L: POI #1 Inflow Area = 229,561 sf, 43.83% Impervious, Inflow Depth = 5.46" for 100-yr event Inflow = 25.34 cfs @ 12.03 hrs, Volume= 104,533 cf Primary = 25.34 cfs @ 12.03 hrs, Volume= 104,533 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Link 5L: POI #1 Hyd rog raph ■ Inflow 28 -r---------+-------1--T--r----1--7--r----------r--r--I-- Primary cfs 26 + 25.34 --------- --+--------'--'-irif�O1�V ill' �=42YJU" 5111 sf- 24 I I 20 I I I I I I I I I I I I I I I I I I I I I I I 18 -- -+--+--+-+--+--+--+-+--+--+--+--+-+--+--+----+--+--+--+-+-- w 16 U .... I I I 3 14 'I 1 -- L--'- - -'-- J--+-----'-- J - -+--L --'-- J-- 1 -- L-----'-- 1 -- L --L --'-- 0 a 12 -- rt--r--r--I-- --+--r----y--+--r--r-y--+--r-------rt--r--r--I-- 10 ,' 8 -- -----------+------- --+-- ---- --+--------- -- -- ---- 6 I -- I 7--r-------I--r-- ---- --r-- ---- --T--------- --r-- ---- I I I I I I I I I I I I I I I I I I I I I 4 ,�I I -- I --'---'-- I -- I --'---'---- +-------J--'-----'---'-- --'-----'-- I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 40 Summary for Subcatchment 6S: Bypass Ditch DA Runoff = 8.32 cfs @ 12.16 hrs, Volume= 29,576 cf, Depth= 4.01" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=7.87" Area (ac) CN Description 0.000 98 Impervious 0.450 60 Woods 1.580 69 Grass 2.030 67 Weighted Average 2.030 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 23.0 Direct Entry, Post Tc Subcatchment 6S: Bypass Ditch DA Hydrograph 9 ' ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ■Runoff 8.32 cfs 8 TY nl 24 � r 'I - En 7 Runoff area='2.030 arc 6 RUn6ffM61uwnc=29,576 cf ---- ---,----r----------I----T--r----------- -r-- - �� 5 ;Runoff Dep, 3 ---- -----+--+---------- -- --+-- ------------+ 0 2- 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours) Carolina Pet Post Type/1 24-hr 100-yr Rainfall=7.87" Prepared by {enter your company name here} Printed 12/22/2021 HydroCAD®10.00-25 s/n 09478 ©2019 HydroCAD Software Solutions LLC Page 41 Summary for Subcatchment 7S: Untreated DA #2 Runoff = 10.11 cfs @ 12.25 hrs, Volume= 43,465 cf, Depth= 3.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-120.00 hrs, dt= 0.03 hrs Type II 24-hr 100-yr Rainfall=7.87" Area (ac) CN Description 0.000 98 Impervious 3.560 60 Woods 0.140 69 Grass 3.700 60 Weighted Average 3.700 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 30.0 Direct Entry, Post Tc Subcatchment 7S: Untreated DA #2 Hydrograph 11 � II II II II II II II II II II II II II II II II II II II II ■Runoff 10.11 cfs 10 Typq II'124-I�r 9 '1� 01-yr I ai�lnfall=7:1871" 8 Runoff area=3.700 arc 7 ftn6ff V61uwnd=43,465 c N - -- - --+-- -- -- ----+--+--+Runoff-Dep1h 3.24►,-- 6- 0 I I I I I I I I I I I I I I I I I LL 5 O O --+--+-- --+--+-��y/�I --I-------�N VQ-- 4 3 - -r- --- -- -- ------------ -- -- -- -- --------- -- -- -- -- -- 2 1 I I I I I I I I I I I I I I I I I I I I I 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time (hours)