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Home My WebLink About241 1st Ave Tech Report 20-Jul-2021Technical Information Report Jim Thomas Residence Single Family Residential Construction 241 1st Ave Southeast Carmel, IN 46033 23‐Aug‐2021 Prepared For: Jim Thomas 4918 Deer Ridge Drive Carmel, IN 46033 Prepared By: William A. Cash 212 Redwood Circle Noblesville, IN 46062 Table of Contents I. Coversheet II. Narrative a. Existing Conditions b. Developed Conditions c. Summary III. Technical Design a. Site Location Map b. Existing Basin Map c. Overall Combined Lot Area Summary d. Soils Map e. Pre & Post CN Data Charts f. Rainfall Data g. Detention Model Schematic h. Stage Storage Graph i. 10 Yr Peak Runoff Graph j. 100 Yr Peak Runoff Graph k. Storage Volume vs. Time Graph l. 10 Yr Design Model Input/Output m. 100 Yr Design Model Input/Output Project Narrative Existing Conditions The property owner plans to replat and combine the 241 1st Ave parcel with the parcel immediately north for a combined total 0.399 acre parcel. Previously the parcels contained approximately 14% impervious surface which consisted of a house and garage. Both structures were removed in anticipation of the new project. For the purpose of this report the existing condition CN for the HSG B soils was taken from the provided Urban Development CN table as defined for a typical 0.25 ac residential lot development. Drainage generally sheet flows from the northeast to southwest. Drainage crossing the south boundary enters onto the existing stone alley and then flows west towards 1st Avenue. The combined parcel area was divided into two drainage basins consisting of a North Basin and a South Basin. The development is limited to the South Basin therefore the presented calculations pertain to this 0.260 acre area. Proposed Conditions The onsite improvements consist of a new 5,719 sf home, driveway and stormwater improvements. The offsite improvements consist of the conversion of the stone alley to asphalt pavement. To address the additional runoff from the larger home the owner plans to install a total 210 linear feet of perforated 12” underground detention piping. The perforated HDPE pipe will drain to a stone envelop consisting of approximately 40% void space. The system will provide an approximate 550 cubic feet of storage and function to attenuate the 10 yr and 100 year developed storm peak runoff rates. The provided calculation confirms the that the proposed development should not generate peak discharges which would exceed the existing rates. The following table outlines the pre and post release rates. Return Time Existing Qp Post Undetained Qp Post Detained Qp 10 Year 0.43 0.66 0.41 100 Year 1.05 1.39 0.77 Summary The residential project will involve stormwater improvements including underground detention, sumped/hooded drainage basins, and an offsite infiltration trench. All drainage from the new roof will drain directly to the underground detention system. A smaller diameter discharge line from the detention system directs the flow to the south and discharges to the alley. The paved alley drains west to 1st Avenue. The detention system attenuates the 10 Yr and 100 Year peak flow to rates to the existing conditions comparable to a 0.25 Acre residential lot development. Site Location Map Project Site Parcel Consolidation GRAVEL GRAVEL850 85185084984884784684 5844843842850 849 848 84 7 846 845 844 84 3843 842 841 840 846851 844843842843844 841 849848847846845844843SCALE: 1" = 60' PROJECT LOCATION CARMEL VIEW RESIDENTIAL DEVELOPMENT EXISTING OFFSITE BASIN MAP DATE: 14-JUL-211ST AVENUECARMEL VIEW DR. Area Summary 241 1st Ave Carmel, IN 46033 Existing Conditions Area [sf] Total Area 17,388 House 1,850 Garage 665 Turf 14,873 % Coverage 14% Proposed Conditions Area [sf] Total Area 17,388 House 5,719 Driveway 580 Walk 140 Turf 10,949 % Coverage 37% Soil Map—Hamilton County, Indiana Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 7/18/2021 Page 1 of 34425420 4425430 4425440 4425450 4425460 4425470 4425480 4425490 4425500 44255104425430 4425440 4425450 4425460 4425470 4425480 4425490 4425500 4425510574650 574660 574670 574680 574690 574700 574710 574650 574660 574670 574680 574690 574700 574710 39° 58' 35'' N 86° 7' 33'' W39° 58' 35'' N86° 7' 30'' W39° 58' 32'' N 86° 7' 33'' W39° 58' 32'' N 86° 7' 30'' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 16N WGS84 0 20 40 80 120 Feet 0 5 10 20 30 Meters Map Scale: 1:452 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features 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 1:15,800. 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: Hamilton County, Indiana Survey Area Data: Version 21, Jun 4, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 1, 2018—Sep 30, 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. Soil Map—Hamilton County, Indiana Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 7/18/2021 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI YmsB2 Miami silt loam-Urban land complex, 2 to 6 percent slopes, eroded 0.9 100.0% Totals for Area of Interest 0.9 100.0% Soil Map—Hamilton County, Indiana Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 7/18/2021 Page 3 of 3 Undeveloped Land Curve Numbers Urban CN Table Page 10 of 120 NRCS HSG Table Urban CN Table 200-6 TABLE 201-2: Rainfall Intensities for Various Return Periods and Storm Durations Rainfall Intensity (Inches/Hour) Return Period (Years)Duration 2 5 10 25 50 100 5 Min. 4.63 5.43 6.12 7.17 8.09 9.12 10 Min. 3.95 4.63 5.22 6.12 6.90 7.78 15 Min. 3.44 4.03 4.55 5.33 6.01 6.77 20 Min. 3.04 3.56 4.02 4.71 5.31 5.99 30 Min. 2.46 2.88 3.25 3.81 4.29 4.84 40 Min. 2.05 2.41 2.71 3.18 3.59 4.05 50 Min. 1.76 2.06 2.33 2.73 3.07 3.47 1 Hr. 1.54 1.80 2.03 2.38 2.68 3.03 1.5 Hrs. 1.07 1.23 1.42 1.63 1.91 2.24 2 Hrs. 0.83 0.95 1.11 1.37 1.60 1.87 3 Hrs. 0.59 0.72 0.84 1.04 1.22 1.42 4 Hrs. 0.47 0.58 0.68 0.84 0.99 1.15 5 Hrs. 0.40 0.49 0.58 0.71 0.83 0.97 6 Hrs. 0.35 0.43 0.50 0.62 0.72 0.85 7 Hrs. 0.31 0.38 0.44 0.55 0.64 0.75 8 Hrs. 0.28 0.34 0.40 0.49 0.57 0.67 9 Hrs. 0.25 0.31 0.36 0.45 0.52 0.61 10 Hrs. 0.23 0.28 0.33 0.41 0.48 0.56 12 Hrs. 0.20 0.24 0.29 0.35 0.41 0.48 14 Hrs. 0.17 0.22 0.25 0.31 0.36 0.42 16 Hrs. 0.16 0.19 0.23 0.28 0.32 0.38 18 Hrs. 0.14 0.17 0.20 0.25 0.29 0.34 20 Hrs. 0.13 0.16 0.19 0.23 0.27 0.31 24 Hrs. 0.11 0.14 0.16 0.20 0.23 0.27 Source: Purdue,A.M., et. al., "Statistical Characteristics of Short Time Incremental Rainfall", Aug., 1992. (Values in this table are based on IDF equation and coefficients provided for Indianapolis, IN.) TABLE 201-3: Rainfall Depths for Various Return Periods Page 11 of 120 Exh. D Rainfall Depth (Inches) Return Period (Years)Duration 2 5 10 25 50 100 24 Hrs. 2.66 3.27 3.83 4.72 5.52 6.46 Source: Purdue,A.M., et. al., "Statistical Characteristics of Short Time Incremental Rainfall", Aug., 1992.(Values in this table are based on IDF equation and coefficients provided for Indianapolis, IN.) TABLE 201-4: NRCS Type 2 Rainfall Distribution Ordinates (for use when not already built in the computer program ) Cumulative Percent Cumulative Percent of Storm Depth Cumulative Percent Cumulative Percent of Storm Depthof Storm Time of Storm Time 0 0 52 73 4 1 53 75 10 2.5 54 77 15 4 55 78 20 6 56 80 25 8 57 81 30 10 58 82 33 12 60 83.5 35 13 63 86 38 15 65 87 40 16.5 67 88 42 19 70 89.5 43 20 72 91 44 21 75 92 45 22 77 93 46 23 80 94 47 26 83 95 48 30 85 96 48.5 34 87 97 48.7 37 90 98 49 50 95 99 50 64 100 100 51 71 200-7 Page 12 of 120 Stormwater Model Schematic Stage Storage Chart South Basin 10 Year Pre & Post Runoff Ex. 10 Yr South Basin Post 10 Yr South Basin Undetained Post 10 Yr South Basin Detained South Basin 100 Year Pre & Post Runoff Ex. 100 Yr South Basin Post 100 Yr South Basin Undetained Post 100 Yr South Basin Detained 100 Yr Total Volume Stored STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Project Description UG Detention Model.SPF Project Options CFS Elevation SCS TR-20 SCS TR-55 Hydrodynamic NO NO Analysis Options Jul 17, 2021 00:00:00 Jul 18, 2021 08:00:00 Jul 17, 2021 00:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:00:30 days hh:mm:ss 1 seconds Rainfall Details SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall ID Source ID Type Units Period Depth Distribution (years) (inches) 1 Time Series 10_Yr Cumulative inches None None 10 3.83 SCS Type II 24-hr File Name ....................................................... Flow Units ...................................................... Elevation Type ............................................... Hydrology Method ......................................... Time of Concentration (TOC) Method .......... Link Routing Method ...................................... Runoff (Dry Weather) Time Step .................. Runoff (Wet Weather) Time Step ................. Reporting Time Step ...................................... Routing Time Step ......................................... Enable Overflow Ponding at Nodes .............. Skip Steady State Analysis Time Periods ..... Start Analysis On ........................................... End Analysis On ............................................ Start Reporting On ......................................... Antecedent Dry Days ..................................... STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin Summary Subbasin Area Weighted Total Total Total Peak ID Curve Rainfall Runoff Runoff Runoff Number Volume (ac) (in) (in) (ac-in) (cfs) Ex_South_Basin 0.26 75.00 3.83 1.54 0.40 0.44 Pavement 0.02 98.00 3.83 3.27 0.06 0.10 Post_South_Basin 0.26 82.22 3.83 2.08 0.54 0.66 Roof 0.13 98.00 3.83 3.59 0.47 0.64 Turf 0.11 61.00 3.83 0.73 0.08 0.08 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Node Summary Element Invert Ground/Rim Initial Peak Max HGL ID Elevation (Max) Water Inflow Elevation Elevation Elevation Attained (ft) (ft) (ft) (cfs) (ft) DS_East 845.44 847.00 845.44 0.00 845.44 DS_West 845.65 847.00 845.65 0.00 845.65 Swal_Basin 844.10 845.50 844.10 0.03 844.52 Deten_Out 843.00 0.41 843.35 Ex_Out 843.00 0.43 843.00 Post_Out 0.00 0.66 0.00 Storage 843.50 846.39 843.50 0.64 844.52 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Link Summary Element From To (Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Node Elevation Elevation (ft) (ft) (ft) (%) (in) (cfs) (cfs) Pipe DS_East Storage 144.00 845.00 844.00 0.6900 8.000 0.0150 0.00 1.05 Pipe DS_West Storage 165.00 845.00 844.00 0.6100 8.000 0.0150 0.00 1.05 Pipe Storage Deten_Out 74.00 843.50 843.00 0.6800 4.250 0.0130 0.27 0.18 Pipe Swal_Basin Storage 20.00 844.10 844.00 0.5000 12.000 0.0150 0.03 2.18 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin Hydrology Subbasin : Ex_South_Basin Input Data Area (ac) ..........................................................................0.26 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 75.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 0.25_AC_Res 0.26 - 75.00 Composite Area & Weighted CN 0.26 75.00 Time of Concentration TOC Method : SCS TR-55 Sheet Flow Equation : Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where : Tc = Time of Concentration (hr) 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: Tc = Time of Concentration (hr) 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 (hr) 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 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subarea Subarea Subarea Sheet Flow Computations A B C Manning's Roughness : 0.40 0.00 0.00 Flow Length (ft) : 100 0.00 0.00 Slope (%) : 3.5 0.00 0.00 2 yr, 24 hr Rainfall (in) : 2.66 0.00 0.00 Velocity (ft/sec) : 0.09 0.00 0.00 Computed Flow Time (min) : 18.83 0.00 0.00 Subarea Subarea Subarea Shallow Concentrated Flow Computations A B C Flow Length (ft) : 80 0.00 0.00 Slope (%) : 3.5 0.00 0.00 Surface Type : Unpaved Unpaved Unpaved Velocity (ft/sec) : 3.02 0.00 0.00 Computed Flow Time (min) : 0.44 0.00 0.00 Total TOC (min) ..................19.27 Subbasin Runoff Results Total Rainfall (in) ..............................................................3.83 Total Runoff (in) ...............................................................1.54 Peak Runoff (cfs) .............................................................0.44 Weighted Curve Number ................................................. 75.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:19:16 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Pavement Input Data Area (ac) ..........................................................................0.02 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 98.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Drive_Walk 0.02 B 98.00 Composite Area & Weighted CN 0.02 98.00 Time of Concentration User-Defined TOC override (minutes): 5 Subbasin Runoff Results Total Rainfall (in) ..............................................................3.83 Total Runoff (in) ...............................................................3.27 Peak Runoff (cfs) .............................................................0.10 Weighted Curve Number ................................................. 98.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:05:00 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Post_South_Basin Input Data Area (ac) ..........................................................................0.26 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 82.22 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Impervious 0.15 B 98.00 Turf 0.11 B 61.00 Composite Area & Weighted CN 0.26 82.22 Time of Concentration User-Defined TOC override (minutes): 15 Subbasin Runoff Results Total Rainfall (in) ..............................................................3.83 Total Runoff (in) ...............................................................2.08 Peak Runoff (cfs) .............................................................0.66 Weighted Curve Number ................................................. 82.22 Time of Concentration (days hh:mm:ss) ......................... 0 00:15:00 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Roof Input Data Area (ac) ..........................................................................0.13 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 98.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number House_Roof 0.13 - 98.00 Composite Area & Weighted CN 0.13 98.00 Time of Concentration User-Defined TOC override (minutes): 5 Subbasin Runoff Results Total Rainfall (in) ..............................................................3.83 Total Runoff (in) ...............................................................3.59 Peak Runoff (cfs) .............................................................0.64 Weighted Curve Number ................................................. 98.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:05:00 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Turf Input Data Area (ac) ..........................................................................0.11 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 61.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Turf 0.11 B 61.00 Composite Area & Weighted CN 0.11 61.00 Time of Concentration User-Defined TOC override (minutes): 15 Subbasin Runoff Results Total Rainfall (in) ..............................................................3.83 Total Runoff (in) ...............................................................0.73 Peak Runoff (cfs) .............................................................0.08 Weighted Curve Number ................................................. 61.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:15:00 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Junction Input SN Element Invert Ground/Rim Ground/Rim Initial Initial ID Elevation (Max) (Max) Water Water Elevation Offset Elevation Depth (ft) (ft) (ft) (ft) (ft) 1 DS_East 845.44 847.00 1.56 845.44 0.00 2 DS_West 845.65 847.00 1.35 845.65 0.00 3 Swal_Basin 844.10 845.50 1.40 844.10 0.00 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Junction Results SN Element Peak Peak Max HGL Max HGL Time of ID Inflow Lateral Elevation Depth Max HGL Inflow Attained Attained Occurrence (cfs) (cfs) (ft) (ft) (days hh:mm) 1 DS_East 0.00 0.00 845.44 0.00 0 00:00 2 DS_West 0.00 0.00 845.65 0.00 0 00:00 3 Swal_Basin 0.03 0.00 844.52 0.42 0 12:04 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SEREV 2DATE: 23-Aug-2021Pipe InputSN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No. ofID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate BarrelsElevation Offset Elevation Offset Height(ft) (ft) (ft) (ft) (ft) (ft) (%) (in) (in) (cfs)1 8in_East 144.00 845.00 -0.44 844.00 0.50 1.00 0.6900 CIRCULAR 8.040 8.040 0.0150 0.5000 0.5000 0.0000 0.00 No 12 8in_West 165.00 845.00 -0.65 844.00 0.50 1.00 0.6100 CIRCULAR 8.040 8.040 0.0150 0.5000 0.5000 0.0000 0.00 No 13 Control_Pipe 74.00 843.50 0.00 843.00 0.00 0.50 0.6800 CIRCULAR 4.200 4.200 0.0130 0.5000 0.5000 0.0000 0.00 No 14 Swal_Stor 20.00 844.10 0.00 844.00 0.50 0.10 0.5000 CIRCULAR 12.000 12.000 0.0150 0.5000 0.5000 0.0000 0.00 No 1 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel ID Flow Peak Flow Capacity Design Flow Velocity Time Occurrence Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) 1 8in_East 0.00 0 00:00 1.05 0.00 0.00 2 8in_West 0.00 0 00:00 1.05 0.00 0.00 3 Control_Pipe 0.27 0 12:04 0.18 1.45 2.71 0.46 4 Swal_Stor 0.03 0 11:54 2.18 0.01 0.45 0.74 STORMWATER DETENTION MODEL 10 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Storage Nodes Storage Node : Storage Input Data 843.50 846.39 2.89 843.50 0.00 0.00 0.00 Output Summary Results 0.64 0.64 0.27 0.00 844.52 1.02 843.56 0.06 0 12:04 0.000 0 0 0.00 Invert Elevation (ft) ........................................................... Max (Rim) Elevation (ft) ................................................... Max (Rim) Offset (ft) ......................................................... Initial Water Elevation (ft) ................................................. Initial Water Depth (ft) ...................................................... Ponded Area (ft²) .............................................................. Evaporation Loss .............................................................. Peak Inflow (cfs) ............................................................... Peak Lateral Inflow (cfs) ................................................... Peak Outflow (cfs) ............................................................ Peak Exfiltration Flow Rate (cfm) .................................... Max HGL Elevation Attained (ft) ...................................... Total Time Flooded (min) ................................................. Total Retention Time (sec) ............................................... Max HGL Depth Attained (ft) ............................................ Average HGL Elevation Attained (ft) ............................... Average HGL Depth Attained (ft) ..................................... Time of Max HGL Occurrence (days hh:mm) .................. Total Exfiltration Volume (1000-ft³) .................................. Total Flooded Volume (ac-in) ........................................... STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Project Description UG Detention Model.SPF Project Options CFS Elevation SCS TR-20 SCS TR-55 Hydrodynamic NO NO Analysis Options Jul 17, 2021 00:00:00 Jul 18, 2021 08:00:00 Jul 17, 2021 00:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:00:30 days hh:mm:ss 1 seconds Rainfall Details SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall ID Source ID Type Units Period Depth Distribution (years) (inches) 1 Time Series 100_Yr Cumulative inches None None 100 6.46 SCS Type II 24-hr Runoff (Dry Weather) Time Step .................. Runoff (Wet Weather) Time Step ................. Reporting Time Step ...................................... Routing Time Step ......................................... Enable Overflow Ponding at Nodes .............. Skip Steady State Analysis Time Periods ..... Start Analysis On ........................................... End Analysis On ............................................ Start Reporting On ......................................... Antecedent Dry Days ..................................... File Name ....................................................... Flow Units ...................................................... Elevation Type ............................................... Hydrology Method ......................................... Time of Concentration (TOC) Method .......... Link Routing Method ...................................... STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin Summary Subbasin Area Weighted Total Total Total Peak ID Curve Rainfall Runoff Runoff Runoff Number Volume (ac) (in) (in) (ac-in) (cfs) Ex_South_Basin 0.26 75.00 6.46 3.68 0.95 1.05 Pavement 0.02 98.00 6.46 6.17 0.10 0.16 Post_South_Basin 0.26 82.22 6.46 4.44 1.14 1.39 Roof 0.13 98.00 6.46 6.22 0.81 1.09 Turf 0.11 61.00 6.46 2.32 0.25 0.31 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Node Summary Element Invert Ground/Rim Initial Peak Max HGL ID Elevation (Max) Water Inflow Elevation Elevation Elevation Attained (ft) (ft) (ft) (cfs) (ft) DS_East 845.44 847.00 845.44 0.04 845.52 DS_West 845.65 847.00 845.65 0.00 845.65 Swal_Basin 844.10 845.50 844.10 0.13 845.50 Deten_Out 843.00 0.77 843.35 Ex_Out 843.00 1.05 843.00 Post_Out 0.00 1.39 0.00 Storage 843.50 846.39 843.50 1.09 845.50 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Link Summary Element From To (Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity Node Elevation Elevation (ft) (ft) (ft) (%) (in) (cfs) (cfs) Pipe DS_East Storage 144.00 845.00 844.00 0.6900 8.000 0.0150 0.04 1.05 Pipe DS_West Storage 165.00 845.00 844.00 0.6100 8.000 0.0150 0.00 1.05 Pipe Storage Deten_Out 74.00 843.50 843.00 0.6800 4.250 0.0130 0.36 0.18 Pipe Swal_Basin Storage 20.00 844.10 844.00 0.5000 12.000 0.0150 0.13 2.18 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin Hydrology Subbasin : Ex_South_Basin Input Data Area (ac) ..........................................................................0.26 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 75.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number 0.25_AC_Res 0.26 - 75.00 Composite Area & Weighted CN 0.26 75.00 Time of Concentration TOC Method : SCS TR-55 Sheet Flow Equation : Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where : Tc = Time of Concentration (hr) 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: Tc = Time of Concentration (hr) 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 (hr) 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 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subarea Subarea Subarea Sheet Flow Computations A B C Manning's Roughness : 0.40 0.00 0.00 Flow Length (ft) : 100 0.00 0.00 Slope (%) : 3.5 0.00 0.00 2 yr, 24 hr Rainfall (in) : 2.66 0.00 0.00 Velocity (ft/sec) : 0.09 0.00 0.00 Computed Flow Time (min) : 18.83 0.00 0.00 Subarea Subarea Subarea Shallow Concentrated Flow Computations A B C Flow Length (ft) : 80 0.00 0.00 Slope (%) : 3.5 0.00 0.00 Surface Type : Unpaved Unpaved Unpaved Velocity (ft/sec) : 3.02 0.00 0.00 Computed Flow Time (min) : 0.44 0.00 0.00 Total TOC (min) ..................19.27 Subbasin Runoff Results Total Rainfall (in) ..............................................................6.46 Total Runoff (in) ...............................................................3.68 Peak Runoff (cfs) .............................................................1.05 Weighted Curve Number ................................................. 75.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:19:16 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Pavement Input Data Area (ac) ..........................................................................0.02 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 98.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Drive_Walk 0.02 B 98.00 Composite Area & Weighted CN 0.02 98.00 Time of Concentration User-Defined TOC override (minutes): 5 Subbasin Runoff Results Total Rainfall (in) ..............................................................6.46 Total Runoff (in) ...............................................................6.17 Peak Runoff (cfs) .............................................................0.16 Weighted Curve Number ................................................. 98.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:05:00 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Post_South_Basin Input Data Area (ac) ..........................................................................0.26 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 82.22 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Impervious 0.15 B 98.00 Turf 0.11 B 61.00 Composite Area & Weighted CN 0.26 82.22 Time of Concentration User-Defined TOC override (minutes): 15 Subbasin Runoff Results Total Rainfall (in) ..............................................................6.46 Total Runoff (in) ...............................................................4.44 Peak Runoff (cfs) .............................................................1.39 Weighted Curve Number ................................................. 82.22 Time of Concentration (days hh:mm:ss) ......................... 0 00:15:00 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Roof Input Data Area (ac) ..........................................................................0.13 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 98.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number House_Roof 0.13 - 98.00 Composite Area & Weighted CN 0.13 98.00 Time of Concentration User-Defined TOC override (minutes): 5 Subbasin Runoff Results Total Rainfall (in) ..............................................................6.46 Total Runoff (in) ...............................................................6.22 Peak Runoff (cfs) .............................................................1.09 Weighted Curve Number ................................................. 98.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:05:00 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Subbasin : Turf Input Data Area (ac) ..........................................................................0.11 Peak Rate Factor .............................................................484.00 Weighted Curve Number ................................................. 61.00 Rain Gage ID ...................................................................* Composite Curve Number Area Soil Curve Soil/Surface Description (acres) Group Number Turf 0.11 B 61.00 Composite Area & Weighted CN 0.11 61.00 Time of Concentration User-Defined TOC override (minutes): 15 Subbasin Runoff Results Total Rainfall (in) ..............................................................6.46 Total Runoff (in) ...............................................................2.32 Peak Runoff (cfs) .............................................................0.31 Weighted Curve Number ................................................. 61.00 Time of Concentration (days hh:mm:ss) ......................... 0 00:15:00 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Junction Input SN Element Invert Ground/Rim Ground/Rim Initial Initial ID Elevation (Max) (Max) Water Water Elevation Offset Elevation Depth (ft) (ft) (ft) (ft) (ft) 1 DS_East 845.44 847.00 1.56 845.44 0.00 2 DS_West 845.65 847.00 1.35 845.65 0.00 3 Swal_Basin 844.10 845.50 1.40 844.10 0.00 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Junction Results SN Element Peak Peak Max HGL Max HGL Time of ID Inflow Lateral Elevation Depth Max HGL Inflow Attained Attained Occurrence (cfs) (cfs) (ft) (ft) (days hh:mm) 1 DS_East 0.04 0.00 845.52 0.08 0 12:05 2 DS_West 0.00 0.00 845.65 0.00 0 00:00 3 Swal_Basin 0.13 0.00 845.50 1.40 0 12:03 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SEREV 2DATE: 23-Aug-2021Pipe InputSN Element Length Inlet Inlet Outlet Outlet Total Average Pipe Pipe Pipe Manning's Entrance Exit/Bend Additional Initial Flap No. ofID Invert Invert Invert Invert Drop Slope Shape Diameter or Width Roughness Losses Losses Losses Flow Gate BarrelsElevation Offset Elevation Offset Height(ft) (ft) (ft) (ft) (ft) (ft) (%) (in) (in) (cfs)1 8in_East 144.00 845.00 -0.44 844.00 0.50 1.00 0.6900 CIRCULAR 8.040 8.040 0.0150 0.5000 0.5000 0.0000 0.00 No 12 8in_West 165.00 845.00 -0.65 844.00 0.50 1.00 0.6100 CIRCULAR 8.040 8.040 0.0150 0.5000 0.5000 0.0000 0.00 No 13 Control_Pipe 74.00 843.50 0.00 843.00 0.00 0.50 0.6800 CIRCULAR 4.200 4.200 0.0130 0.5000 0.5000 0.0000 0.00 No 14 Swal_Stor 20.00 844.10 0.00 844.00 0.50 0.10 0.5000 CIRCULAR 12.000 12.000 0.0150 0.5000 0.5000 0.0000 0.00 No 1 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Pipe Results SN Element Peak Time of Design Flow Peak Flow/ Peak Flow Travel ID Flow Peak Flow Capacity Design Flow Velocity Time Occurrence Ratio (cfs) (days hh:mm) (cfs) (ft/sec) (min) 1 8in_East 0.04 0 12:04 1.05 0.04 0.23 10.43 2 8in_West 0.00 0 00:00 1.05 0.00 0.00 3 Control_Pipe 0.36 0 12:04 0.18 1.97 3.68 0.34 4 Swal_Stor 0.13 0 12:04 2.18 0.06 0.44 0.76 STORMWATER DETENTION MODEL 100 Year Design 241 1st Ave SE REV 2 DATE: 23-Aug-2021 Storage Nodes Storage Node : Storage Input Data 843.50 846.39 2.89 843.50 0.00 0.00 0.00 Output Summary Results 1.09 1.09 0.53 0.00 845.50 2 843.60 0.1 0 12:04 0.000 0 0 0.00 Total Time Flooded (min) ................................................... Total Retention Time (sec) ................................................. Max HGL Depth Attained (ft) .............................................. Average HGL Elevation Attained (ft) .................................. Average HGL Depth Attained (ft) ....................................... Time of Max HGL Occurrence (days hh:mm) .................... Total Exfiltration Volume (1000-ft³) .................................... Total Flooded Volume (ac-in) ............................................. Evaporation Loss ................................................................ Peak Inflow (cfs) ................................................................. Peak Lateral Inflow (cfs) ..................................................... Peak Outflow (cfs) .............................................................. Peak Exfiltration Flow Rate (cfm) ....................................... Max HGL Elevation Attained (ft) ......................................... Invert Elevation (ft) .............................................................. Max (Rim) Elevation (ft) ...................................................... Max (Rim) Offset (ft) ........................................................... Initial Water Elevation (ft) ................................................... Initial Water Depth (ft) ......................................................... Ponded Area (ft²) ................................................................