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HomeMy WebLinkAboutSW3181201_Stormwater Report_20220407Storm Water Management/Erosion & Sediment Control Report Rob Wallace Park — Phase IIB 12922 Bethel School Road Midland, North Carolina PREPARED FOR Cabarrus County February 22, 2022 Alfred Benesch & Company 2359 Perimeter Pointe Parkway Suite 350 Charlotte, NC 28208 www.benesch.com P: 704.521.9880 0A,l�"I, t rs *t 0 Corporate Certifications: NC P.E.: F-1320 NC L.A.: C-454 io bwo%nesch TABLE OF CONTENTS SECTION 1 Project Description 1.1 Location 1.2 Topography/Drainage 1.3 Soils 1.4 Model Parameters/Analysis SECTION 2 Conveyance Design 2.1 Hydraflow Express Summary SECTION 3 Sedimentation and Erosion Control Measures 3.1 Temporary Skimmer Basin Calculations 3.2 Riprap Apron Calculations 3.3 Swale Lining Calculations SECTION 4 Appendix 4.1 USGS Quad Map 4.2 Soils Map SECTION 5 Drainage Area Maps 5.1 Drainage Area Map Obenesch CVt(-' 'P�ubkc :,dfety Driving Range j Storm Water Management Report/ Erosion and Sedimentation Control Plan 2 Section 1 Projection Description Rob Wallace Park - Phase II Midland, North Carolina Storm Water Management Report Project Description This project involves the construction of a playground, restroom, and picnic shelters near the recently completed Rob Wallace Park Phase 2 improvements. In addition to the structures, a new 23 space parking lot to serve the proposed amenities, as well as several short crushed concrete walking trail connectors. The project will be constructed in a single phase starting with the construction of the structures and playground and ending with the parking lot construction. During construction, there will also be an extension of the private water main that parallels the park road to serve a new hydrant and restroom. Project construction will take place on tax parcel 55447239550000, which is 111.8 acres. The total site area of the park property, combining several other parcels allocated for future park development, is 173.2 acres. The current property owner is Cabarrus County, who will be the financially responsible party. The area to be disturbed is approximately 2.95 acres. Topography/Drainage The site is currently mostly undeveloped and drains to the south. Runoff is undetdined and collects in Muddy Creek along the southern portion of the property that drains directly to Rocky River. Rocky River is located 2 miles southeast of the site and is classified as a Class C surface water. Stormwater management for this project is accomplished utilizing vegetated conveyances with low impact methods. The proposed parking lot runoff sheets off the paved surface through a grass road shoulder. The parking lot final grade nearly matches existing grade to prevent the need for deep ditches or re- channelizing runoff. Minimal storm drainage pipe is being installed to convey runoff under road/trail crossings. The site is currently mostly undeveloped and has minimal BUA (Built -Upon Area) from Phase II. The proposed BUA upon completion of this project (including that already constructed in Phase II) is 10.0 acres (9.3 acres existing and 0.7 acres proposed). Therefore, this development is classified as low - density (6.7% BUA). Soils The soil survey of Gaston County indicates that soils on the site are as follows: • Badin Channery Silt Loam - BaB (Class C) • Chewacla Sandy Loam - ChA (Class B/D) • Kirksey Silt Loam - KkB (Class C) • Misenheimer Channery Silt Loam - MsA (Class C/D) • Udorthents, Loamy - Ud (Class C) Rob Wallace Park - Phase II Midland, North Carolina Model Parameters/Analysis Capacity analysis for proposed storm water conveyance system design was performed using the Rational Method (10 year frequency). Storm conveyance modeling and calculations were completed using the Autodesk Hydraflow Express Extension for Civil 3D software and Benesch's spreadsheets. Refer to the drainage area maps in the appendix section of this report. Section 2 Conveyance Design Rob Wallace Park - Phase 1113 Swale Runoff Calcs - Revised 8.29.22 RAW AREA (SF) ACRES Swale 1 76,656.00 1.76 Land Total C INDIVIDUAL C Drainage Area 1 LAND 69,554.00 1.60 Pervious 0.30 0.27 7,102.00 0.16Impervious 0.95 0.09 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 76,656.00 1.76 0.36 4.68 Swale 2 108,888.00 2.50 Land Total C INDIVIDUAL C Drainage Areas 1, 1A LAND 88,541.00 2.03 Pervious 0.30 0.24 20,347.00 0.47Impervious 0.95 0.18 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 108,888.00 2.50 0.42 7.79 Swale 3 111,113.00 2.55 Land Total C INDIVIDUAL C Drainage Areas 1, 1A, 113 LAND 105,906.00 2.43 Pervious 0.301 0.25 22,512.00 0.52Impervious 0.951 0.17 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 128,418.00 2.95 0.41 9.02 Swale 4 67,434.00 1.55 Land Total C INDIVIDUAL C Drainage Areas 2, 5,6 & 7 LAND 18,831.00 0.43 Pervious 0.30 0.08 48,603.00 1.12Impervious 0.95 0.68 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 67,434.00 1.55 0.77 8.79 Swale 5 33,880.00 0.78 Land Total C INDIVIDUAL C Clean Water LAND 29,116.00 0.67 Pervious 0.30 0.26 4,764.00 0.11Impervious 0.95 0.13 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 33,880.00 0.78 0.39 2.25 Swale 6 22,154.00 0.51 Land Total C INDIVIDUAL C Drainage Area 9 LAND 13,542.00 0.31 Pervious 0.30 0.18 8,612.00 0.20Impervious 0.95 0.37 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 22,154.00 0.51 0.55 2.08 Swale 7 20,909.00 0.48 Land Total C INDIVIDUAL C Drainage Area 10 LAND 6,907.00 0.16 Pervious 0.30 0.10 14,002.00 0.32Impervious 0.95 0.64 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 20,909.00 0.48 0.74 2.61 Swale 8 6,368.00 0.15 Land Total C INDIVIDUAL C Drainage Area 11 LAND 1,382.00 0.03 Pervious 0.30 0.06 4,986.00 0.11Impervious 0.95 0.74 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 6,368.00 0.15 0.81 0.87 Swale 9 8,309.00 0.19 Land Total C INDIVIDUAL C Drainage Area 12 LAND 3,541.00 0.08 Pervious 0.30 0.13 4,768.00 0.11Impervious 0.95 0.55 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 8,309.00 0.19 0.67 0.95 Swale 10 5,232.00 0.12 Land Total C INDIVIDUAL C Drainage Area 13 LAND 1,211.00 0.03 Pervious 0.30 0.07 4,021.00 0.09Impervious 0.95 0.73 ROOF 0.00 0.00 Roof 0.95 0.00 Q10 TOTAL 5.232.00 0.12 0.80 0.71 Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #1 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 511.63 Slope (%) = 1.88 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 4.68 Elev (ft) Section 513.00 512.50 512.00 511.50 511.00 1 2 3 4 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) 5 6 Reach (ft) Wednesday, Aug 31 2022 = 0.45 = 4.680 = 1.51 = 3.10 = 4.85 = 0.45 = 4.70 = 0.60 Depth (ft) 1.37 1 :l 0.37 -0.13 RdSe7 7 8 9 10 - -- Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #2 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 507.13 Slope (%) = 3.74 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 7.79 Elev (ft) Section 509.00 508.50 507.50 507.00 506.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.49 Q (cfs) = 7.790 Area (sqft) = 1.70 Velocity (ft/s) = 4.58 Wetted Perim (ft) = 5.10 Crit Depth, Yc (ft) = 0.59 Top Width (ft) = 4.94 EGL (ft) = 0.82 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.87 1.37 1 :l 0.37 -0.13 RdSe7 Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #3 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 503.77 Slope (%) = 2.32 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 9.02 Elev (ft) Section 505.00 504.50 504.00 503.50 503.00 1 2 3 4 Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) 5 6 Reach (ft) Wednesday, Aug 31 2022 = 0.60 = 9.020 = 2.28 = 3.96 = 5.79 = 0.63 = 5.60 = 0.84 Depth (ft) 1.23 0.73 0.23 -0.27 RIir1 7 8 9 10 - Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #4 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 498.22 Slope (%) = 2.22 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 8.79 Elev (ft) Section 500.00 499.50 499.00 498.50 498.00 497.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.60 Q (cfs) = 8.790 Area (sqft) = 2.28 Velocity (ft/s) = 3.86 Wetted Perim (ft) = 5.79 Crit Depth, Yc (ft) = 0.63 Top Width (ft) = 5.60 EGL (ft) = 0.83 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.78 1.28 0.78 0.28 -0.22 W2WM Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale - 5 - Clean Water Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 510.01 Slope (%) = 1.88 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 2.25 Elev (ft) Section 512.00 511.50 511.00 510.50 510.00 509.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.31 Q (cfs) = 2.250 Area (sqft) = 0.91 Velocity (ft/s) = 2.48 Wetted Perim (ft) = 3.96 Crit Depth, Yc (ft) = 0.30 Top Width (ft) = 3.86 EGL (ft) = 0.41 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.99 1.49 0.49 -0.01 WMIS Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale - 6 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 503.11 Slope (%) = 3.58 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 2.08 Elev (ft) Section 505.00 504.50 504.00 503.50 503.00 502.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.25 Q (cfs) = 2.080 Area (sqft) = 0.69 Velocity (ft/s) = 3.03 Wetted Perim (ft) = 3.58 Crit Depth, Yc (ft) = 0.28 Top Width (ft) = 3.50 EGL (ft) = 0.39 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.89 1.39 0.39 -0.11 ■iftx Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #7 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 504.99 Slope (%) = 1.06 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 2.61 Elev (ft) 506.00 505.50 505.00 504.50 Section Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth, Yc (ft) Top Width (ft) EGL (ft) 1 2 3 4 5 6 7 8 Reach (ft) Wednesday, Aug 31 2022 = 0.39 = 2.610 = 1.24 = 2.11 = 4.47 = 0.32 = 4.34 = 0.46 Depth (ft) 1.01 0.51 0.01 -0.49 -0.99 9 10 Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #8 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 503.41 Slope (%) = 3.39 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.87 Elev (ft) Section 505.00 504.50 504.00 503.50 503.00 502.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.16 Q (cfs) = 0.870 Area (sqft) = 0.40 Velocity (ft/s) = 2.19 Wetted Perim (ft) = 3.01 Crit Depth, Yc (ft) = 0.17 Top Width (ft) = 2.96 EGL (ft) = 0.23 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.59 1.09 0.59 -0.41 ■rzz Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #9 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 503.16 Slope (%) = 2.55 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.95 Elev (ft) Section 505.00 504.50 504.00 503.50 503.00 502.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.18 Q (cfs) = 0.950 Area (sqft) = 0.46 Velocity (ft/s) = 2.08 Wetted Perim (ft) = 3.14 Crit Depth, Yc (ft) = 0.18 Top Width (ft) = 3.08 EGL (ft) = 0.25 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 1.84 1.34 0.84 0.34 -0.16 ■r.T_rN Channel Report Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Swale #10 Trapezoidal Bottom Width (ft) = 2.00 Side Slopes (z:1) = 3.00, 3.00 Total Depth (ft) = 1.00 Invert Elev (ft) = 49859.00 Slope (%) = 3.32 N-Value = 0.030 Calculations Compute by: Known Q Known Q (cfs) = 0.71 Elev (ft) Section 49861.00 49860.50 49860.00 49859.50 49859.00 49858.50 Wednesday, Aug 31 2022 Highlighted Depth (ft) = 0.14 Q (cfs) = 0.710 Area (sqft) = 0.34 Velocity (ft/s) = 2.10 Wetted Perim (ft) = 2.89 Crit Depth, Yc (ft) = 0.15 Top Width (ft) = 2.84 EGL (ft) = 0.21 1 2 3 4 5 6 7 8 9 10 Reach (ft) Depth (ft) 2.00 1.50 1.00 0.50 wixffel Section 3 Sedimentation and Erosion Control Measures 10,10 30 Outlet W = Do + La pipe 1 diameter (Do) T ilwater < 0.50o ----- 1 to 40ok Py dill, 50 Discharge (0/sec) Appendices Curves may not be extrapolated. Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter). CULVERT #1A & 1 B: 4.26 CFS Rev. 12193 8.06.3 Appendices 30,. i L S L 3 5 10 20 50 100 200 500 1000 Discharge (ft3/sec) Curves may not be extrapolated, Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter). CULVERT #3A & 3 B: 1.24 C F S Rev. 12/93 8.06.3 Appendices V, Discharge (ft3/sec) Curves may not be extrapolated. Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter). CULVERT #4: 2.63 CFS Rev. 12t93 8.06.3 Appendices A 3 b It) 20 50 100 200 500 1000 Discharge (ft3/sec) Curves may not be extrapolated. Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter). CULVERT #5: 5.93 CFS Rev. 12193 8.06.3 Appendices 30.. ----TT 3 b 10 20 50 100 200 500 1000 Discharge (ft3/sec) Curves may not be extrapolated. Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw c 0.5 diameter). CULVERT #6: 2.86 CFS F- 4" Rev. 12/93 8.06.3 Discharge (O/sec) Curves may not be extrapolated. Appendices Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (iw < 0.5 diameter). CULVERT #7: 8.79 CFS 8.06.3 A Rev. 12193 Section 4 Appendix ZUSGSU.S. DEPARTMENT OF T E INTERIOR MIDLAND QUADRANGLE U.S. GEOLOGICAL SURVEY Mfozo �T —0. 01 7.5 MINWE SERTS PRO EST ConWiactic 8"W55W 1�1 S-1, 97 by---- --- --- HIT; L 93 Y. 4F 1� S 4 sl NOS LI 'm H-hl 37 38 3a 11 4) An 515"x"E ITE Entrance Fj J-d FIFIA MIDLAND; NC 2.1 35° 14'6" N 35° 13' 50" N a Soil Map—Cabarrus County, North Carolina 3 (Rob Wallace Park Soils) a M 35° 14 6" N I 543880 543DV 544000 544060 544120 544180 544240 3 3 Map Scale: 1:2,480 fi printed on A portrait (8.5" x ll") sheet. o $ Meters N 0 35 70 140 210 Feet 0 100 200 400 600 Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 17N WGS84 USDA Natural Resources Web Soil Survey 2/22/2022 %+ Conservation Service National Cooperative Soil Survey Page 1 of 3 35° 1350" N m c 0 c`a U r � Z 'o U �� 7a o U � O as as a O O Of O. m 2 O (n a) •� N w as U a) 0N2 7p U) N L 1U a7 p -O O co M y O` a O N Q) U m `p at E a) N 7 E '5 y w- a co O N O E — y CL CL O V t6 O C >a) > 7 a U a} G O. O co N 'O m E Z C U = 00 @ O 10 L O N _ U N O E N U O O y C L m W M n N 7 p O a) a) N U 0' U N o O L L C 5 a) ` a) 3 �' y E n3 3 O O O cn Q a) U C - >m N a) O Z Lo p N ti 'S a E ya O '> Q O yo a) d y c6 p W a N C 7 C" Q O N '� O O O U M 0. O N L y C Q N O T C a) a) c N O 70 N E y .O a) O U (6 lO O L C O N 7 —Oi 2 cu U. >. > I p O a) O E > N C V — O V N N O E >` N N Z N 2 a •fp O (>O C a L 0 a) yp N O N a5 7 N U 0 p .00 V) E C N p• a) E a) N S a) a o a0 0_ � @ >� ���0 ao u g mo�_ Q O O cn "' E U (E 7 J a)_�� U y O. c N (t6 U> N .0 C O m E o E � ash Z N a �Q co) c cv `—° o N O� y E C H J >+ L N N 05.2 t6 N D 100, O .O 7 > — a)w m?� �a (a) as(m ��4 E o�> oaQm Z 7 o U cmaoiuoi a)NEop oC >, �Um =3�f°c_7i o 5.Fo Q� 2 _`o m no nE w� o) Ea)c°'i� �'a) o—m c Eck Ogoaoi�? o� a ZQ o_O a) cu 'O O N C E O a a) cn O. O N N 7 O ) ,� O a5 > N. 7 >, �> Co 0 � N N �_ O) O O� �} � N O m 7 C N C O U w E_ m M 4) a) a E = O p N p UU O. 2 a) 7 a) O N •O U a=0Q � L _O = U) U) o 'O !n U� O f6 �co) E O E ca SE w F- U n) t- o IL— a m m LL y ca c U m _ L n. m d c N _rn rn N Q U U) J m E d ° Y O O 'o L a O m N C a y � c m N U m U D a Z R d m o y c a W 0 R F- m W J y o 0 p y m� S o d O Q U) N a° -j EL E y a c c c a o a°a) d O. O_ am m 0 .. U p o O OC co O dQO ca L 00 a LL >> ID a) E c -On 2 0 TO aa) LYN V Q 000c U) w U •o p ca m o ro c) c) >> J J g c a) o a x co c U U (0F) ° o U m a 0 c f; 0 a`' d w ' 'tX``'• t „, @ X AN o0 y 13 Q to Z� 7 0 U — 0 CO a �U m c O m Z Soil Map—Cabarrus County, North Carolina Rob Wallace Park Soils Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI BaB Badin channery silt loam, 2 to 7.31 43.1 % i, 8 percent slopes - ChA Chewacia sand loam, 0 to 2 - — --------- ----percent - - - - - 0. 0.0 j 0.0%' slopes, frequently flooded KkB - ----- - -- -- - Kirksey silt loam, 1 to 6 8.3 49.5% percent slopes MsA Misenheimer channery silt 1.1 6.6%', loam, 0 to 4 percent slopes ~Ud - — Udorthents, loamy— --------- 0.1� -- ----- ---- 0.7% Totals for Area of Interest 16.8 100.0% USDA Natural Resources Web Soil Survey 2/22/2022 Conservation Service National Cooperative Soil Survey Page 3 of 3 Section 5 Drainage Area Maps