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Home My WebLink AboutDrainage Report2 081922 10505 North College Avenue | Indianapolis, IN 46280 | .www.weihe.net | (317) 846-6611 | (800) 452-6408 | Fax: (317) 843-0546 Allan H. Weihe, P.E., L.S., - Founder STORMWATER TECHNICAL REPORT For: Whataburger Chenal Parkway and Sulu Road, Little Rock AR Project #W220196 Prepared For: TMG Construction Management 15420 Endeavor Dr Noblesville IN 46060 Tele – (317) 282-0653 Contact Person: Mr. Mike Goins Prepared By: Scott Rucker, P.E. (IN) Certified By: Date: 27 June, 2022 Revised: 26 July, 2022 PROJECT NARRATIVE Whataburger Drainage Report Weihe Engineers, INC. 7/26/2022 Stormwater Technical Report Whataburger Little Rock, AR Project #W220196 Project Narrative: TMG Construction Management is proposing to build a new Whataburger restaurant on an approximately 1.2 acre parcel located at the northeast corner of Chenal Pkwy and Sulu Rd. The proposed construction is on a site at a Latitude of N 34° 45' 37" and Longitude W 92° 27' 13". The site is located in Section 36, Township 2 North, Range 14 West, Pulaski County, Arkansas. Please refer to Figure 1.1 Floodzone: Based upon a scaled interpretation of the Flood Insurance Map No.05119C0314H for the City of Little Rock, AR, dated June 7, 2019, the subject tract is located within Zone X Please refer to Figure 1.2. Stormwater Design: This development is being designed in conjunction with the neighboring property to the north, a proposed Taco Bell restaurant. The site grading and stormwater systems for each property have been designed simultaneously. The Whataburger property will capture stormwater runoff from approximately 1.07 acres including some areas on the north property not captured by the Taco Bell system. Some perimeter areas of the site will discharge directly to the right-of-way. The proposed development will include an underground detention basin with a flow restricting structure that will store and release the site’s stormwater runoff per the requirements set forth by the City’s ordinance. The site will discharge to the south, releasing into the right-of-way up-stream of an existing culvert under Sulu Rd. The Taco Bell detention system will outlet directly into the Whataburger detention system. The Whataburger system has been designed to convey this additional water as a “pass through” flow. Existing Conditions: Currently parcel is mostly wooded with some grassy cover fronting the right-of-way. The project site is adjoined by a commercial property to the north, Chenal Pkwy to the west, Sulu Rd to the south, and an undeveloped wooded parcel to the east. The property consists of the following soil types: Carnasaw-Urban land complex; Carnasaw- Mountainburg undulating; and Carnasaw-Mountainburg steep. A soil map has been included with this report. Curve numbers and runoff coefficients were assigned using existing land use in conjunction with soils mapping from the Natural Resource Conservation (NRCS). An abbreviated NRCS Soils Report has been included with this report. The existing conditions of the controlled drainage area have been analyzed to determine the allowable post-developed release rates. A software model was created using Hydraflow Hydrographs to determine Whataburger Drainage Report Weihe Engineers, INC. 7/26/2022 the peak release rate for the 25-year event using the SCS method and a 6-hour distribution. A Curve Number, CN, of 77 was used for the 1.07-acre area. Calculation summaries and software reports have been included with this report. Please refer to Figure 2.1. Proposed Conditions: The proposed on-site storm sewer system will capture approximately 1.07 acres of the proposed developed area. Runoff from the controlled drainage area will be captured and conveyed to an underground detention system located on the south side of the site. The site will discharge to the southeast, releasing into the right-of-way upstream of an existing storm sewer culvert. Please refer to Figure 2.2. A weighted Curve Number CN was developed for the proposed conditions of the controlled drainage area. A software model was created using Hydraflow Hydrographs to determine the peak release rates for the 25-year event using the SCS 6 hour distribution. The Taco Bell detention system will outlet directly to the proposed Whataburger detention system. This additional stormwater flow has been treated as a “pass through” flow. The hydrograph for the Taco Bell detention system was added to the hydrograph for the proposed Whataburger site. The combined hydrograph was then routed through the Whataburger detention system. The peak flow rate from the Taco Bell detention was added to the Whataburger allowable outlet rate to determine the peak allowable release rate for the combined system. The model was used to design the underground detention system and outlet control structure in order to meet the allowable release rate. Calculation summaries, software reports, and an outlet detail have been included with this report. Please refer to Figure 3.1 for a detail of the outlet control structure. The computed 25-year peak run-off rates for the existing and proposed conditions have been summarized below. Peak flow from Taco Bell 1.99 cfs Whataburger 10-yr Existing Peak flow 2.38 cfs Total Allowable Release Rate for Whataburger system 4.37 cfs Total Proposed Release Rate from Whataburger system 4.34 cfs Storm Sewers The storm sewer system is designed to convey stormwater runoff at a minimum velocity of 2.5 feet/second through the HDPE conveyance pipes while maintaining a hydraulic grade line elevation within the system during a 25-year storm event. For sizing of the storm sewer network, the controlled drainage basin was broken down into a total of three (3) contributing sub-basins based on proposed grading plans and structure locations. A weighted runoff coefficient, C, was calculated for each sub- basin and the time of concentration was assumed to be 5 minutes. Rainfall intensity data was taken from figure 2-5 of the ordinance. Please refer to Figure 2.3. DETENTION CALCULATIONS Project: Date: Job No: Prepared By:SSR BASIN: Existing Conditions - Entire Site Area (SF) Area (Ac.) CN 3655 0.08 98 0 0.00 98 4061 0.09 80 51332 1.18 77 TOTA L =59048 1.36 78.51 % Impervious 6.2 BASIN:Existing Conditions - Controlled Drainage Area Area (SF) Area (Ac.) CN 0 0.00 98 0 0.00 98 46505 1.07 77 TOTA L =46505 1.07 77.00 % Impervious 0.0 BASIN:Proposed Conditions - Entire Site Area (SF) Area (Ac.) CN 36575 0.84 98 4970 0.11 98 17503 0.40 80 TOTA L =59048 1.36 92.66 % Impervious 70.4 BASIN:Proposed Conditions - Controlled Drainage Area Area (SF) Area (Ac.) CN 32231 0.74 98 4939 0.11 98 9335 0.21 80 TOTA L =46505 1.07 94.39 % Impervious 79.9 Roof Wooded Cover type Pavement Roof Grass Whataburger - Little Rock July 25, 2022 W220196 Existing and Proposed Runoff Calculations Cover type Pavement Roof Grass Wooded Cover type Pavement Grass Cover type Pavement Roof 1 2 45 7 8 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Project: WB Ex - Pr Det - perf pipe - SCS.gpw Tuesday, 07 / 26 / 2022 Hydrograph Return Period Recap Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph No. type hyd(s) Description (origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr 1 SCS Runoff ------ ------- ------- ------- ------- ------- 3.049 ------- ------- Taco Bell - Proposed 2 Reservoir 1 ------- ------- ------- ------- ------- 1.997 ------- ------- Taco Bell Det Outlet 4 SCS Runoff ------ ------- ------- ------- ------- ------- 2.381 ------- ------- Whataburger Existing 5 SCS Runoff ------ ------- ------- ------- ------- ------- 3.654 ------- ------- Whataburger Proposed 7 Combine 2, 5, ------- ------- ------- ------- ------- 5.420 ------- ------- Total To WB Det 8 Reservoir 7 ------- ------- ------- ------- ------- 4.340 ------- ------- Whataburger Outlet Proj. file: WB Ex - Pr Det - perf pipe - SCS.gpw Tuesday, 07 / 26 / 2022 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Hydrograph Summary Report Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval Peak volume hyd(s) elevation strge used Description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 SCS Runoff 3.049 2 144 12,502 ------ ------ ------ Taco Bell - Proposed 2 Reservoir 1.997 2 154 12,498 1 515.34 2,474 Taco Bell Det Outlet 4 SCS Runoff 2.381 2 150 10,105 ------ ------ ------ Whataburger Existing 5 SCS Runoff 3.654 2 144 15,417 ------ ------ ------ Whataburger Proposed 7 Combine 5.420 2 144 27,914 2, 5, ------ ------ Total To WB Det 8 Reservoir 4.340 2 154 27,911 7 512.03 3,197 Whataburger Outlet WB Ex - Pr Det - perf pipe - SCS.gpw Return Period: 25 Year Tuesday, 07 / 26 / 2022 Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 1 Taco Bell - Proposed Hydrograph type = SCS Runoff Peak discharge = 3.049 cfs Storm frequency = 25 yrs Time to peak = 144 min Time interval = 2 min Hyd. volume = 12,502 cuft Drainage area = 0.940 ac Curve number = 91.4 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.88 in Distribution = SCS 6-Hr Storm duration = 6.00 hrs Shape factor = 484 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (min) Taco Bell - Proposed Hyd. No. 1 -- 25 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 2 Taco Bell Det Outlet Hydrograph type = Reservoir Peak discharge = 1.997 cfs Storm frequency = 25 yrs Time to peak = 154 min Time interval = 2 min Hyd. volume = 12,498 cuft Inflow hyd. No. = 1 - Taco Bell - Proposed Max. Elevation = 515.34 ft Reservoir name = Taco Bell - Det Max. Storage = 2,474 cuft Storage Indication method used. 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (min) Taco Bell Det Outlet Hyd. No. 2 -- 25 Year Hyd No. 2 Hyd No. 1 Total storage used = 2,474 cuft Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Pond No. 1 - Taco Bell - Det Pond Data UG Chambers -Invert elev. = 512.65 ft, Rise x Span = 2.50 x 2.50 ft, Barrel Len = 155.00 ft, No. Barrels = 2, Slope = 0.10%, Headers = Yes Encasement -Invert elev. = 512.15 ft, Width = 3.75 ft, Height = 3.25 ft, Voids = 40.00% Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 512.15 n/a 0 0 0.34 512.49 n/a 128 128 0.68 512.83 n/a 181 309 1.02 513.17 n/a 267 576 1.36 513.51 n/a 308 884 1.70 513.85 n/a 327 1,210 2.04 514.19 n/a 331 1,542 2.38 514.53 n/a 323 1,865 2.72 514.87 n/a 300 2,165 3.06 515.21 n/a 247 2,411 3.40 515.56 n/a 168 2,580 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 12.00 7.00 0.00 0.00 Span (in)= 12.00 7.00 0.00 0.00 No. Barrels = 1 1 0 0 Invert El. (ft)= 512.15 512.15 0.00 0.00 Length (ft)= 131.00 0.10 0.00 0.00 Slope (%)= 1.24 0.50 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a Yes No No Crest Len (ft)= 0.00 0.00 0.00 0.00 Crest El. (ft)= 0.00 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = --- --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Contour) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). 0.00 0.50 1.00 1.50 2.00 2.50 3.00 Stage (ft) 0.00 512.15 1.00 513.15 2.00 514.15 3.00 515.15 4.00 516.15 Elev (ft) Discharge (cfs) Stage / Discharge Total Q Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 4 Whataburger Existing Hydrograph type = SCS Runoff Peak discharge = 2.381 cfs Storm frequency = 25 yrs Time to peak = 150 min Time interval = 2 min Hyd. volume = 10,105 cuft Drainage area = 1.070 ac Curve number = 77 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 10.00 min Total precip. = 4.88 in Distribution = SCS 6-Hr Storm duration = 6.00 hrs Shape factor = 484 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 Q (cfs) Time (min) Whataburger Existing Hyd. No. 4 -- 25 Year Hyd No. 4 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 5 Whataburger Proposed Hydrograph type = SCS Runoff Peak discharge = 3.654 cfs Storm frequency = 25 yrs Time to peak = 144 min Time interval = 2 min Hyd. volume = 15,417 cuft Drainage area = 1.070 ac Curve number = 94.4 Basin Slope = 0.0 % Hydraulic length = 0 ft Tc method = User Time of conc. (Tc) = 5.00 min Total precip. = 4.88 in Distribution = SCS 6-Hr Storm duration = 6.00 hrs Shape factor = 484 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 Q (cfs) Time (min) Whataburger Proposed Hyd. No. 5 -- 25 Year Hyd No. 5 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 7 Total To WB Det Hydrograph type = Combine Peak discharge = 5.420 cfs Storm frequency = 25 yrs Time to peak = 144 min Time interval = 2 min Hyd. volume = 27,914 cuft Inflow hyds. = 2, 5 Contrib. drain. area = 1.070 ac 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 6.00 Q (cfs) Time (min) Total To WB Det Hyd. No. 7 -- 25 Year Hyd No. 7 Hyd No. 2 Hyd No. 5 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Hyd. No. 8 Whataburger Outlet Hydrograph type = Reservoir Peak discharge = 4.340 cfs Storm frequency = 25 yrs Time to peak = 154 min Time interval = 2 min Hyd. volume = 27,911 cuft Inflow hyd. No. = 7 - Total To WB Det Max. Elevation = 512.03 ft Reservoir name = Whataburger Det Max. Storage = 3,197 cuft Storage Indication method used. 0 60 120 180 240 300 360 420 Q (cfs) 0.00 0.00 1.00 1.00 2.00 2.00 3.00 3.00 4.00 4.00 5.00 5.00 6.00 6.00 Q (cfs) Time (min) Whataburger Outlet Hyd. No. 8 -- 25 Year Hyd No. 8 Hyd No. 7 Total storage used = 3,197 cuft Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Pond No. 2 - Whataburger Det Pond Data UG Chambers -Invert elev. = 508.85 ft, Rise x Span = 3.00 x 3.00 ft, Barrel Len = 140.00 ft, No. Barrels = 2, Slope = 0.10%, Headers = Yes Encasement -Invert elev. = 508.35 ft, Width = 4.50 ft, Height = 4.00 ft, Voids = 40.00% Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 508.35 n/a 0 0 0.41 508.76 n/a 185 185 0.83 509.18 n/a 275 460 1.24 509.59 n/a 381 841 1.66 510.01 n/a 423 1,264 2.07 510.42 n/a 441 1,705 2.48 510.83 n/a 441 2,146 2.90 511.25 n/a 423 2,570 3.31 511.66 n/a 381 2,950 3.73 512.08 n/a 275 3,226 4.14 512.49 n/a 222 3,448 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 12.00 11.00 0.00 0.00 Span (in)= 12.00 11.00 0.00 0.00 No. Barrels = 1 1 0 0 Invert El. (ft)= 508.35 508.35 0.00 0.00 Length (ft)= 36.00 0.10 0.00 0.00 Slope (%)= 2.56 0.50 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a Yes No No Crest Len (ft)= 0.00 0.00 0.00 0.00 Crest El. (ft)= 0.00 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = --- --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Wet area) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 Stage (ft) 0.00 508.35 1.00 509.35 2.00 510.35 3.00 511.35 4.00 512.35 5.00 513.35 Elev (ft) Discharge (cfs) Stage / Discharge Total Q Hydraflow Rainfall Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Tuesday, 07 / 26 / 2022 Return Intensity-Duration-Frequency Equation Coefficients (FHA) Period (Yrs)B D E (N/A) 1 0.0000 0.0000 0.0000 -------- 2 0.0000 0.0000 0.0000 -------- 3 0.0000 0.0000 0.0000 -------- 5 0.0000 0.0000 0.0000 -------- 10 258.0115 37.2000 0.9963 -------- 25 56.6689 11.2000 0.6812 -------- 50 0.0000 0.0000 0.0000 -------- 100 54.7483 10.0000 0.6279 -------- File name: Little Rock IDF.IDF Intensity = B / (Tc + D)^E Return Intensity Values (in/hr) Period (Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60 1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10 6.20 5.55 5.02 4.58 4.21 3.90 3.63 3.40 3.19 3.01 2.85 2.70 25 8.50 7.08 6.13 5.44 4.91 4.50 4.16 3.88 3.64 3.44 3.26 3.10 50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100 10.00 8.34 7.25 6.47 5.87 5.40 5.02 4.69 4.42 4.19 3.98 3.80 Tc = time in minutes. Values may exceed 60. Rainfall Precipitation Table (in) Precip. file name: H:\2022\W220195\Engineering\design\drainage\pond modeling\Little Rock AR.pcp Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour 0.00 0.00 0.00 0.00 6.12 7.40 8.45 9.57 SCS 6-Hr 0.00 0.00 0.00 0.00 4.14 4.88 5.46 6.07 Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 PIPE SIZING CALCULATIONS Project: Date: Job No: Prepared By:SSR BASIN:200 Area (SF) Area (Ac.) C - 10yr C - 25yr C - 100yr 10865 0.25 0.90 0.92 0.95 0 0.00 0.90 0.92 0.95 1744 0.04 0.22 0.28 0.35 TOTAL =12609 0.29 0.81 0.83 0.87 BASIN:202 Area (SF) Area (Ac.) C - 10yr C - 25yr C - 100yr 14593 0.34 0.90 0.92 0.95 425 0.01 0.90 0.92 0.95 6688 0.15 0.22 0.28 0.35 TOTAL =21706 0.50 0.69 0.72 0.77 BASIN:300 Area (SF) Area (Ac.) C - 10yr C - 25yr C - 100yr 6773 0.16 0.90 0.92 0.95 4514 0.10 0.90 0.92 0.95 903 0.02 0.22 0.28 0.35 TOTAL =12190 0.28 0.85 0.87 0.91 Impervious, Pavement Impervious, Roof Cover type Impervious, Pavement Impervious, Roof Pervious, Grass Whataburger - Little Rock July 25, 2022 W220196 Cover type Proposed Sub-Basin "C" Calculations Cover type Impervious, Pavement Impervious, Roof Pervious, Grass Pervious, Grass TRENCH DRAIN UNDERGROUND DETENTION STR 103 - OUTLET CONTROL STR 202 - CATCH BASIN STR 200 - CATCH BASIN STR 300 - CATCH BASIN STR 102 - MANHOLE STR 100 - END SECTION 25-YEAR STORM 100-YEAR STORM RAINFALL AND SOIL DATA Hydrologic Soil Group—Pulaski County, Arkansas Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/16/2022 Page 1 of 438465503846570384659038466103846630384665038466703846550384657038465903846610384663038466503846670549940549960549980550000550020550040550060550080550100550120550140 549940 549960 549980 550000 550020 550040 550060 550080 550100 550120 550140 34° 45' 39'' N 92° 27' 15'' W34° 45' 39'' N92° 27' 7'' W34° 45' 35'' N 92° 27' 15'' W34° 45' 35'' N 92° 27' 7'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 45 90 180 270 Feet 0 10 20 40 60 Meters Map Scale: 1:967 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:20,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Pulaski County, Arkansas Survey Area Data: Version 18, Sep 13, 2021 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 14, 2018—Aug 1, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—Pulaski County, Arkansas Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/16/2022 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI CbC Carnasaw-Urban land complex, 3 to 8 percent slopes C 1.5 58.0% CMC Carnasaw-Mountainburg association, undulating C 0.6 21.6% CMF Carnasaw-Mountainburg association, steep C 0.5 20.4% Totals for Area of Interest 2.7 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Hydrologic Soil Group—Pulaski County, Arkansas Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/16/2022 Page 3 of 4 Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—Pulaski County, Arkansas Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 6/16/2022 Page 4 of 4 EXHIBITS FIGURE 1.1 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N E LOCATION MAPWHATABURGER 06-27-2022 NOT TO SCALE - PROJECT LOCATIONCHENAL PKWYKIRK RDRAHLING RDWELLINGTON HILLS RD FIRMette MAP FIGURE 1.2 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S 06-27-2022 WHATABURGER EXISTING DRAINAGE AREA FIGURE 2.1 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N E 07-26-2022 WHATABURGER SITE BOUDNARY 1.36 ACRES CN=78.5 PICKUP HERE ORDER F 6" 1 1/2" PROPOSED DRAINAGE AREA FIGURE 2.2 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N E CONTROLLED DRAINAGE AREA 1.07 ACRES CN=93.8 PROPOSED TACO BELL DEVELOPMENT 06-27-2022 WHATABURGER WHATABURGER BUILDING FFE = 517.00 PICKUP HERE ORDER F 6" 1 1/2" PROPOSED DRAINAGE SUB-BASINS FIGURE 2.3 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N E 07-26-2022 WHATABURGER SUB-BASIN 202 0.50 AC C = 0.72SUB-BASIN 300 0.28 AC C = 0.87 SUB-BASIN 200 0.29AC C = 0.83 WHATABURGER BUILDING FFE = 517.00 F 6" 1 1/2" FIGURE 2.4 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N EWHATABURGER DETENTION OVERFLOW ELEVATION = 512.77 WHATABURGER BUILDING FFE = 517.00 DIRECTION ARROWS FOR DETENTION OVER FLOW ROUTING PROPOSED FLOOD ROUTING (100-YR STORM EVENT) 07-26-2022 FIGURE 3.1 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S DETAIL NO SCALE CASTING FRAME & COVER AS SPECIFIED (NEENAH R-1772) RIM ELEV = 514.30 (MATCH PROPOSED GRADE) STANDARD PRECAST MANHOLE CAP 16" TOP OF RISER ELEV = 512.10 12" OUTLET PIPE INV = 508.35 12" X 12" X 12" TEE STANDARD 48" MANHOLE STRUCTURE FULL HEIGHT MANHOLE STEPS AS REQUIRED 12" INLET PIPE INV = 508.85 BASE SET ON 6" OF #8 STONE 6" 24" 3"MIN. 11" ORIFICE INV = 508.35 12" CAP STR 103 - OUTLET CONTROL SUPPORT RISER PIPE AS NEEDED 6" UNDERDRAIN INV = 508.35 6" MIN WHATABURGER 06-27-2022