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Home My WebLink AboutDrainage Report1 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: Taco Bell Chenal Parkway and Sulu Road, Little Rock AR Project #W220195 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: 25 July, 2022 PROJECT NARRATIVE Taco Bell Drainage Report Weihe Engineers, INC. 7/25/2022 Stormwater Technical Report Taco Bell Little Rock, AR Project #W220195 Project Narrative: TMG Construction Management is proposing to build a new Taco Bell 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 south, a proposed Whataburger restaurant. The site grading and stormwater systems for each property have been designed simultaneously. The Taco Bell property will capture stormwater runoff from approximately 0.94 acres of the site. Some areas of the site will discharge directly to the right-of-way and some areas will flow south, into the Whataburger storm system. The Whataburger site has been designed to accept and detain the additional stormwater runoff. 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 detention system will discharge to the south, releasing into the Whataburger detention system. The Whataburger detention system has been designed to accommodate this flow as a “pass through”. Stormwater runoff leaving the Whataburger detention system will be directed into the roadside ditch along the north side of Sulu Rd. 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 Taco Bell Drainage Report Weihe Engineers, INC. 7/25/2022 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 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 0.94-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 0.94 acres of the proposed developed area. Runoff from the controlled drainage area will be captured and conveyed to an underground detention system located near the southwest side of the site. The site will discharge to the south, releasing into the detention system for the neighboring Whataburger. The Whataburger system has been designed to accept the post- detention flow from the Taco Bell and allow it to pass through to the outfall in the right- of-way along Sulu Rd. 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 rate for the 25-year event using the SCS 6-hour distribution. 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 outlet details 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. Existing and Proposed Peak Release Rates Existing Q 25-yr = 2.09 cfs Proposed Q 25-yr = 2.00 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 two (2) 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 0 0.00 98 0 0.00 98 52324 1.20 77.00 TOTA L =52324 1.20 77.00 % Impervious 0.0 BASIN:Existing Conditions - Controlled Draiange Area Area (SF) Area (Ac.) CN 0 0.00 98 0 0.00 98 40916 0.94 77.00 TOTA L =40916 0.94 77.00 % Impervious 0.0 BASIN:Proposed Conditions - Entire Site Area (SF) Area (Ac.) CN 25989 0.60 98 2147 0.05 98 24188 0.56 77.00 TOTA L =52324 1.20 88.29 % Impervious 53.8 BASIN:Proposed Conditions - Controlled Drainage Area Area (SF) Area (Ac.) CN 23809 0.55 98 2147 0.05 98 14960 0.34 77.00 TOTA L =40916 0.94 90.32 % Impervious 63.4 Roof Existing and Proposed Runoff Calculations Taco Bell - Little Rock July 22, 2022 W220195 Cover type Pavement Roof Wooded Cover type Pavement Wooded Cover type Pavement Roof Grass Cover type Pavement Roof Grass 1 3 4 Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Project: TB Ex - Pr Det - perf pipe -SCS.gpw Monday, 07 / 25 / 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 ------ ------- ------- ------- ------- ------- 2.091 ------- ------- Taco Bell - Existing 3 SCS Runoff ------ ------- ------- ------- ------- ------- 3.049 ------- ------- Taco Bell - Proposed 4 Reservoir 3 ------- ------- ------- ------- ------- 1.997 ------- ------- Taco Bell Det Outlet Proj. file: TB Ex - Pr Det - perf pipe -SCS.gpw Monday, 07 / 25 / 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 2.091 2 150 8,878 ------ ------ ------ Taco Bell - Existing 3 SCS Runoff 3.049 2 144 12,502 ------ ------ ------ Taco Bell - Proposed 4 Reservoir 1.997 2 154 12,498 3 515.34 2,474 Taco Bell Det Outlet TB Ex - Pr Det - perf pipe -SCS.gpw Return Period: 25 Year Monday, 07 / 25 / 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 Monday, 07 / 25 / 2022 Hyd. No. 1 Taco Bell - Existing Hydrograph type = SCS Runoff Peak discharge = 2.091 cfs Storm frequency = 25 yrs Time to peak = 150 min Time interval = 2 min Hyd. volume = 8,878 cuft Drainage area = 0.940 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) Taco Bell - Existing Hyd. No. 1 -- 25 Year Hyd No. 1 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Monday, 07 / 25 / 2022 Hyd. No. 3 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. 3 -- 25 Year Hyd No. 3 Hydrograph Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Monday, 07 / 25 / 2022 Hyd. No. 4 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. = 3 - 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. 4 -- 25 Year Hyd No. 4 Hyd No. 3 Total storage used = 2,474 cuft Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Monday, 07 / 25 / 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 Hydraflow Rainfall Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2021 Monday, 07 / 25 / 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: 201 Area (SF) Area (Ac.) C - 10yr C - 25yr C - 100yr 3388 0.08 0.90 0.92 0.95 2199 0.05 0.90 0.92 0.95 432 0.01 0.22 0.28 0.35 TOTAL =6019 0.14 0.85 0.87 0.91 BASIN: 202 Area (SF) Area (Ac.) C - 10yr C - 25yr C - 100yr 20910 0.48 0.90 0.92 0.95 0 0.00 0.90 0.92 0.95 13919 0.32 0.22 0.28 0.35 TOTAL =34829 0.80 0.63 0.66 0.71 Pervious, Grass Impervious, Pavement Impervious, Roof Cover type Impervious, Pavement Impervious, Roof Pervious, Grass Taco Bell - Little Rock July 22, 2022 W220195 Cover type Proposed Sub-Basin "C" Calculations 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 MAPTACO BELL 06-21-2022 NOT TO SCALE - PROJECT LOCATIONCHENAL PKWYKIRK RDRAHLING RDWELLINGTON HILLS RD FIRMette MAP FIGURE 1.2 06-21-2022 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S TACO BELL EXISTING DRAINAGE AREA FIGURE 2.1 06-21-2022 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N ETACO BELL ONLY PICKUP HERE ORDER COOLER WOMEN MEN PASSAGE SERVING CUSTOMER DINING DRIVE-THRU OFFICE FREEZER HOOD WASHING UTILITY DRY STORAGE PREP KITCHEN 6" 1 1/2"STMPROPOSED DRAINAGE AREA FIGURE 2.2 07-25-2022 WEIHE weihe.net Indianapolis, Indiana 46280 10505 N. College Avenue 317 | 846 - 6611E N G I N E E R S W S N ETACO BELL CONTROLLED DRAINAGE AREA 0.94 ACRES CN=90.3 PROPOSED WHATABURGER DEVELOPMENT ONLY PICKUP HERE ORDER COOLER WOMEN MEN PASSAGE SERVING CUSTOMER DINING DRIVE-THRU OFFICE FREEZER HOOD WASHING UTILITY DRY STORAGE PREP KITCHEN 6" 1 1/2"STMPROPOSED 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 07-25-2022 TACO BELL SUB-BASIN 402 0.14 AC C = 0.83 SUB-BASIN 403 / 403-A 0.66 AC C = 0.80 ONLY PICKUP HERE ORDER COOLER WOMEN MEN PASSAGE SERVING CUSTOMER DINING DRIVE-THRU OFFICE FREEZER HOOD WASHING UTILITY DRY STORAGE PREP KITCHEN 6" 1 1/2"STMPROPOSED FLOOD ROUTING (100-YR STORM EVENT) 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 E 07-25-2022 TACO BELL DETENTION OVERFLOW ELEVATION: 516.75 SURFACE PONDING OVERFLOW ELEVATION: 517.15 DIRECTION ARROWS FOR DETENTION OVER FLOW ROUTING 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 = 518.00 (MATCH PROPOSED GRADE) STANDARD PRECAST MANHOLE CAP 16" TOP OF RISER ELEV = 515.35 12" OUTLET PIPE INV = 512.15 12" X 12" X 12" TEE STANDARD 48" MANHOLE STRUCTURE FULL HEIGHT MANHOLE STEPS AS REQUIRED 12" INLET PIPE INV = 512.65 BASE SET ON 6" OF #8 STONE 6" 24" 3"MIN. 7" ORIFICE INV = 512.15 12" CAP TACO BELL 07-25-2022 STR 101 - OUTLET CONTROL SUPPORT RISER PIPE AS NEEDED 6" UNDERDRAIN INV = 512.15 6" MIN