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HomeMy WebLinkAboutDrainage Study 121525Drainage Study DRAINAGE REPORT FOR CANTRELL OFFICE PARK & STORAGE BEHIND 14524 CANTRELL RD. REES COMMERCIAL LITTLE ROCK, ARKANSAS SEPTEMBER 18, 2024 TABLE OF CONTENTS RUNOFF CURVE NUMBER TABLE & STORM DATA 100YR REPORT & CALULATIONS (CIVIL 3D SSA) PROPOSED DRAINAGE AREA MAP DRAINAGE AREA MAP RUNOFF CURVE NUMBER TABLE & STORM DATA RUNOFF COEFFICIENTS FOR RATIONAL METHOD RUNOFF COEFFICIENTS LAND USE TYPES COMMERCIAL RESIDENTIAL 0.75 0.60 100YR REPORT & CALULATIONS (CIVIL 3D SSA) Autodesk® Storm and Sanitary Analysis 2024 - Version 13.6.268 (Build 0) ----------------------------------------------------------------------------------------- ******************* Project Description ******************* File Name ................. Storm Drain Analysis.SPF **************** Analysis Options **************** Flow Units ................ cfs Subbasin Hydrograph Method. Modified Rational Time of Concentration...... SCS TR-55 Return Period.............. 100 years Storm Duration............. 6 min Link Routing Method ....... Kinematic Wave Storage Node Exfiltration.. Constant flow Starting Date ............. MAY-24-2023 00:00:00 Ending Date ............... MAY-25-2023 00:00:00 Report Time Step .......... 00:00:10 ************* Element Count ************* Number of subbasins ....... 1 Number of nodes ........... 2 Number of links ........... 1 **************** Subbasin Summary **************** Subbasin Total Area ID acres ------------------------------ watershed 27.35 ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow ft ft ft² ------------------------------------------------------------------------------ FES1-1T JUNCTION 290.40 300.00 0.00 FES1-0T OUTFALL 290.00 295.00 0.00 ************ Link Summary ************ Link From Node To Node Element Length Slope Manning's ID Type ft % Roughness -------------------------------------------------------------------------------------------- SD1-1T FES1-1T FES1-0T CONDUIT 40.0 1.0000 0.0130 ********************* Cross Section Summary ********************* Link Shape Depth/ Width No. of Cross Full Flow Design ID Diameter Barrels Sectional Hydraulic Flow Area Radius Capacity Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis ft ft ft² ft cfs ---------------------------------------------------------------------------------------------- ------------ SD1-1T CIRCULAR 5.00 5.00 1 19.63 1.25 260.44 ************************** Volume Depth Runoff Quantity Continuity acre-ft inches ************************** --------- ------- Total Precipitation ...... 3.825 1.678 Continuity Error (%) ..... 1.000 ************************** Volume Volume Flow Routing Continuity acre-ft Mgallons ************************** --------- --------- External Inflow .......... 0.000 0.000 External Outflow ......... 2.617 0.853 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 0.000 0.000 Continuity Error (%) ..... 0.000 ************************************** Runoff Coefficient Computations Report ************************************** --------------------- Subbasin watershed --------------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- COMMERCIAL 17.23 - 0.75 RESIDENTIAL 10.12 - 0.60 Composite Area & Weighted Runoff Coeff. 27.35 0.69 *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation ------------------- Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation ---------------------------------- V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation --------------------- V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness --------------------- Subbasin watershed --------------------- Sheet Flow Computations ----------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.40 0.00 0.00 Flow Length (ft): 100.00 0.00 0.00 Slope (%): 12.00 0.00 0.00 2 yr, 24 hr Rainfall (in): 4.13 4.13 4.13 Velocity (ft/sec): 0.18 0.00 0.00 Computed Flow Time (minutes): 9.23 0.00 0.00 Shallow Concentrated Flow Computations -------------------------------------- Subarea A Subarea B Subarea C Flow Length (ft): 142.00 58.00 0.00 Slope (%): 12.00 12.00 0.00 Surface Type: Unpaved Paved Unpaved Velocity (ft/sec): 5.59 7.04 0.00 Computed Flow Time (minutes): 0.42 0.14 0.00 Channel Flow Computations ------------------------- Subarea A Subarea B Subarea C Manning's Roughness: 0.01 0.01 0.01 Flow Length (ft): 408.00 518.00 893.00 Channel Slope (%): 9.50 4.60 1.40 Cross Section Area (ft²): 3.25 3.25 12.50 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Wetted Perimeter (ft): 13.50 13.50 12.00 Velocity (ft/sec): 13.67 9.51 13.94 Computed Flow Time (minutes): 0.50 0.91 1.07 ============================================================================================== == Total TOC (minutes): 12.26 ============================================================================================== == *********************** Subbasin Runoff Summary *********************** --------------------------------------------------------------------------------------- Subbasin Accumulated Rainfall Total Peak Weighted Time of ID Precip Intensity Runoff Runoff Runoff Concentration in in/hr in cfs Coeff days hh:mm:ss --------------------------------------------------------------------------------------- watershed 1.68 8.16 1.16 154.07 0.690 0 00:12:15 --------------------------------------------------------------------------------------- ****************** Node Depth Summary ****************** ----------------------------------------------------------------------------------------- Node Average Maximum Maximum Time of Max Total Total Retention ID Depth Depth HGL Occurrence Flooded Time Time Attained Attained Attained Volume Flooded ft ft ft days hh:mm acre-in minutes hh:mm:ss ----------------------------------------------------------------------------------------- FES1-1T 0.03 2.77 293.17 0 00:12 0 0 0:00:00 FES1-0T 0.03 2.77 292.77 0 00:12 0 0 0:00:00 ***************** Node Flow Summary ***************** ------------------------------------------------------------------------------------ Node Element Maximum Peak Time of Maximum Time of Peak ID Type Lateral Inflow Peak Inflow Flooding Flooding Inflow Occurrence Overflow Occurrence cfs cfs days hh:mm cfs days hh:mm ------------------------------------------------------------------------------------ FES1-1T JUNCTION 154.07 154.07 0 00:12 0.00 FES1-0T OUTFALL 0.00 153.90 0 00:12 0.00 *********************** Outfall Loading Summary *********************** ----------------------------------------------- Outfall Node ID Flow Average Peak Frequency Flow Inflow (%) cfs cfs ----------------------------------------------- FES1-0T 1.86 71.06 153.90 ----------------------------------------------- System 1.86 71.06 153.90 ***************** Link Flow Summary Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis ***************** ---------------------------------------------------------------------------------------------- ---------------------------------- Link ID Element Time of Maximum Length Peak Flow Design Ratio of Ratio of Total ReportedType Peak Flow Velocity Factor during Flow Maximum Maximum Time Condition Occurrence Attained Analysis Capacity /Design Flow Surcharged days hh:mm ft/sec cfs cfs Flow Depth minutes -------------------------------------------------------------------------------------------------------------------------------- SD1-1T CONDUIT 0 00:12 13.82 1.00 153.90 260.44 0.59 0.55 0 Calculated ******************************** Highest Flow Instability Indexes ******************************** All links are stable. WARNING 108 : Surcharge elevation defined for Junction FES1-1T is below junction maximum elevation. Assumed surcharge elevation equal to maximum elevation. Analysis began on: Wed Oct 23 12:22:30 2024 Analysis ended on: Wed Oct 23 12:22:31 2024 Total elapsed time: 00:00:01 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis DRAINAGE AREA MAP S1° 52' 31"W 586.80'S11° 36' 47"E 134.49'S40° 05' 05"W 176.22'S62° 53' 31"W 172.92'N88° 39' 29"W 112.87'S16° 10' 28"E 52.94'N88° 28' 52"W 224.54'N87° 41' 30"W 330.56'N1° 48' 01"E 725.30'S45° 40' 33"E 190.73'MAINTAINUNDISTURBEDBUFFERSANITARY RIM = 2 'FL = 2 DRAINAGE AREA MAP CANTRELL OFFICE PARK &CANTRELL SMART STORAGENEAR 14524 HWY 10 - LITTLE ROCK, ARREES COMMERCIAL JESS GRIFFIN, PE5 KINGSTON DRIVELITTLE ROCK, AR 72227TEL (501) 690-3456JESS@GRIFFINPE.COMS W E 1"=60'GRAPHIC SCALE60 0 60DR1SHEET FLOWSHALLOW CONCENTRATED FLOWCHANNEL FLOWDRAINAGE AREA27.35 ACRESCOMMERCIALNEIGHBORHOOD