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HomeMy WebLinkAboutDrainage Report Project: GOAT ADDITION 220 2nd Street SW Carmel, Indiana 46032 Prepared For: STUDIO M ARCHITECTURE 2 West Main Street Carmel, IN 46032 Prepared By: CIVIL & ENVIRONMENTAL CONSULTANTS, INC. Indianapolis, Indiana Civil Engineer: Nicholas Justice CEC Project 322-434 SEPTEMBER 2022 Drainage Report -ii- GOAT Addition September 2022 TABLE OF CONTENTS 1.0 REPORT OVERVIEW .....................................................................................................1 2.0 PROJECT BACKGROUND.............................................................................................1 2.1 Existing conditions.................................................................................................. 1 2.1.1 FEMA Map ..................................................................................................1 2.1.2 Watershed Description .................................................................................1 2.1.3 Soils Map .....................................................................................................1 3.0 STORMWATER DESIGN ...............................................................................................1 3.1 Stormwater Management ........................................................................................ 2 3.1.1 Runoff Curve Number (CN) Determination ................................................2 4.0 CONCLUSION ..................................................................................................................2 5.0 REFERENCES ...................................................................................................................3 APPENDICES Appendix A – FEMA Firm Map Appendix B – Soils Map Appendix C – Existing & Proposed Watershed Maps Appendix D – Storm Sewer Sizing Calculations Appendix E – Existing HydroCAD Output Appendix F – Proposed HydroCAD Output -1- GOAT Addition September 2022 1.0 REPORT OVERVIEW This report establishes the stormwater quantity and quality requirements for the proposed Greatest of All Taverns (GOAT) Addition project located at 220 2nd Street SW. The existing site is approximately 0.234 acres and currently consists of a 1-story restaurant building with a patio and gravel lot. The proposed improvements to the site includes a building addition. Stormwater from the building will be conveyed to the existing storm sewer north of the site. 2.0 PROJECT BACKGROUND 2.1 EXISTING CONDITIONS The project site is located at the northwest corner of Monon Boulevard and 2rd Street SW. The existing site’s subject parcel includes a restaurant building, outdoor patio, and gravel lot. Approximately 0.182 acres of the site drains north to the existing 18” storm sewer that eventually drains to the Morrow Follett drain. Approximately 0.052 acres of the site drains south to the 12” storm sewer in 2nd Street SW. The existing drainage basin map Figure C-1 delineates the drainage areas in Appendix C. The existing discharge rates for the full site are summarized in Table 1. 2.1.1 FEMA Map The project site is located within the FEMA Community Panel Map #18057C0207G dated November 19, 2014 which indicates the site is located within the Flood Designation ‘Zone X, Area of minimal flood hazard” can be found in Appendix A. 2.1.2 Watershed Description The project site drains to the Cool Creek-Grassy Branch/Little Cool Creek watershed as provided on the IndianaMap GIS system and identified with a 14-digit Hydrologic Unit Code (HUC) of 05120201090030. 2.1.3 Soils Map The approximate limits of each soil type are depicted in the Soils Map provided in Appendix B. 3.0 STORMWATER DESIGN The proposed project includes constructing a building addition to the existing restaurant, a new patio, connecting sidewalks, and landscape along the Monon Boulevard. The project will disturb approximately 6,054 square feet (0.139 acres). The impervious area of the site draining north will decrease by approximately 1,113 square feet (0.026 acres). The area of the site draining south will not be disturbed and impervious area will not increase. -2- GOAT Addition September 2022 Refer to the proposed drainage maps Figures C-1 & C-2 in Appendix C. A 24” RCP on the east edge of the property conveys offsite stormwater and drains north to south. The building addition will drain via downspouts to the 24” RCP. Inlet overtopping is not anticipated. Calculations can be found in in Appendix D. 3.1 STORMWATER MANAGEMENT 3.1.1 Runoff Curve Number (CN) Determination For impervious areas such as buildings and pavement, a CN value of 98 was used. The HydroCAD reports in Appendix E and Appendix F show the calculated CN values as well as time of concentration for each site basin. Rainfall depths in the City of Carmel Technical Standards Manual were used to develop the basin hydrographs. Proposed Site % Impervious (CN=98) = 83.3 % Pervious (CN=61) = 16.7 = 83.3% × 98 + 16.7% × 61 = 92 Table 1: Peak Runoff Rates (cfs) North Condition 2-Year 10-Year 100-Year Existing 0.69 0.94 1.66 Proposed 0.60 0.86 1.58 South Condition 2-Year 10-Year 100-Year Existing 0.21 0.29 0.48 Proposed 0.21 0.29 0.48 Complete HyrdroCAD calculations can be found in Appendix E & F. 4.0 CONCLUSION The proposed project will be served with adequate stormwater infrastructure in accordance with the City of Carmel Stormwater Specification Manual. No adverse impacts are expected for upstream or downstream property owners. -3- GOAT Addition September 2022 5.0 REFERENCES 1. USDA NRCS Web Soil Survey 2. U.S. Geological Survey, IndianaMap website 3. FEMA Flood Insurance Rate Maps, FEMA website 4. City of Carmel Stormwater Technical Standards Specifications Manual APPENDIX A FEMA FIRM National Flood Hazard Layer FIRMette 0 500 1,000 1,500 2,000250 Feet Ü SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT SPECIAL FLOOD HAZARD AREAS Without Base Flood Elevation (BFE) Zone A, V, A99 With BFE or DepthZone AE, AO, AH, VE, AR Regulatory Floodway 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mileZone X Future Conditions 1% Annual Chance Flood HazardZone X Area with Reduced Flood Risk due to Levee. See Notes.Zone X Area with Flood Risk due to LeveeZone D NO SCREEN Area of Minimal Flood Hazard Zone X Area of Undetermined Flood HazardZone D Channel, Culvert, or Storm Sewer Levee, Dike, or Floodwall Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation Coastal Transect Coastal Transect Baseline Profile Baseline Hydrographic Feature Base Flood Elevation Line (BFE) Effective LOMRs Limit of Study Jurisdiction Boundary Digital Data Available No Digital Data Available Unmapped This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 6/15/2022 at 12:14 PM and does not reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or become superseded by new data over time. This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for regulatory purposes. Legend OTHER AREAS OF FLOOD HAZARD OTHER AREAS GENERAL STRUCTURES OTHER FEATURES MAP PANELS 8 B 20.2 The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location. 1:6,000 86°8'7"W 39°58'50"N 86°7'30"W 39°58'22"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 APPENDIX B SOILS MAP United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Hamilton County, IndianaNatural Resources Conservation Service June 15, 2022 9 Custom Soil Resource Report Soil Map 442550144255074425513442551944255254425531442553744255434425549442550144255074425513442551944255254425531442553744255434425549574257 574263 574269 574275 574281 574287 574293 574257 574263 574269 574275 574281 574287 574293 39° 58' 36'' N 86° 7' 49'' W39° 58' 36'' N86° 7' 47'' W39° 58' 35'' N 86° 7' 49'' W39° 58' 35'' N 86° 7' 47'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 16N WGS84 0 10 20 40 60 Feet 0 3 7 14 21 Meters Map Scale: 1:244 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI Or Orthents 0.2 100.0% Totals for Area of Interest 0.2 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. Custom Soil Resource Report 11 Hamilton County, Indiana Or—Orthents Map Unit Setting National map unit symbol: 5dbc Elevation: 720 to 980 feet Mean annual precipitation: 36 to 42 inches Mean annual air temperature: 49 to 52 degrees F Frost-free period: 175 to 185 days Farmland classification: Not prime farmland Map Unit Composition Orthents and similar soils:98 percent Minor components:2 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Orthents Setting Landform:Terraces, till plains Properties and qualities Slope:6 to 12 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Other vegetative classification: Trees/Timber (Woody Vegetation) Hydric soil rating: Unranked Minor Components Water Percent of map unit:2 percent Hydric soil rating: No Custom Soil Resource Report 13 APPENDIX C EXISTING & PROPOSED WATERSHED MAPS MONON TRAIL / MONON BOULEVARDDATE:DWG SCALE:DRAWN BY:CHECKED BY:APPROVED BY:PROJECT NO:FIGURE NO.:EXISTING DRAINAGE MAP322-4341" = 10'JUNE 2022NPJACHC-1STUDIO M ARCHITECTUREGOATBUILDING EXPANSION220 2ND STREET SW530 E. Ohio Street, Suite G - Indianapolis, IN 46204317-655-7777 · 877-746-0749 www.cecinc.comNORTH MONON TRAIL / MONON BOULEVARDDATE:DWG SCALE:DRAWN BY:CHECKED BY:APPROVED BY:PROJECT NO:FIGURE NO.:EXISTING DRAINAGE MAP322-4341" = 10'JUNE 2022NPJACHC-2STUDIO M ARCHITECTUREGOATBUILDING EXPANSION220 2ND STREET SW530 E. Ohio Street, Suite G - Indianapolis, IN 46204317-655-7777 · 877-746-0749 www.cecinc.comNORTH APPENDIX D STORM SEWER SIZING CALCULATIONS Civil & Environmental Consultants, Inc. By:NPJ Project Name:GOAT Addition Date:9/2022 CEC Project No.:322-434 Checked By: Description:Composite C Calculations Date: Runoff Coefficient 0.90 0.85 0.20 BASINS RD-1 Roof Surfaces Pavement Pervious Soil/Turf Total Total Composite (ft^2)(ft^2)(ft^2)(ft^2)(Acres)"C" 1,949 0 0 1,949 0.04 0.90 RD-2 Roof Surfaces Pavement Pervious Soil/Turf Total Total Composite (ft^2)(ft^2)(ft^2)(ft^2)(Acres)"C" 789 0 0 789 0.02 0.90 All Watertight Roof Surfaces = Pavement = Slightly Pervious Soil (with Turf) = Civil & Environmental Consultants, Inc.Computed By: NPJChecked By:Project Name:GOAT AdditionCEC Project No.:322-434Date: 9/2022Description: Storm Drain Flow Tabulation Form - Rational Method Storm Frequency Design Year: 10HGL CrownHeadlossLocation Inlet Acres Coef. Sum Time Conc. (min) Int. "Q" = Pipe (full) n = 0.012 Max Q Max V Manhole in MH minus No. Depth Coeff. atfrom to Area sub total "C" CA CA inlet drain total "I" CIA Size length slope full full INV out INV in out MH Crown HGL Cover ManholeRD-10.04 0.90 0.04 57.360.26T.C.=828.40 825.140.62RD-13.310.50RD-1 4000.04 0.04 5.00 0.87 5.877.070.25 8 138 0.50 0.93 2.65 825.09 824.40 825.08 825.76cover =2.64RD-20.02 0.90 0.02 57.360.13T.C.=828.40 824.930.56RD-23.570.50RD-2 4000.02 0.02 5.00 0.19 5.197.300.13 8 43 1.00 1.31 3.75 824.83 824.40 824.82 825.50cover =2.90C A L C U L A T E D D E S I G N APPENDIX E EXISTING HYDROCAD OUTPUT X-N Existing to North X-S Existing to South Routing Diagram for 322-434 X-Site Prepared by CEC, Printed 6/17/2022 HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 100 YR Rainfall=6.46"322-434 X-Site Printed 6/17/2022Prepared by CEC HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Events for Subcatchment X-N: Existing to North Event Runoff (cfs) Volume (acre-feet) Depth (inches) 2 YR 0.69 0.034 2.25 10 YR 0.94 0.048 3.16 100 YR 1.66 0.087 5.75 Type II 24-hr 100 YR Rainfall=6.46"322-434 X-Site Printed 6/17/2022Prepared by CEC HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Events for Subcatchment X-S: Existing to South Event Runoff (cfs) Volume (acre-feet) Depth (inches) 2 YR 0.21 0.012 2.67 10 YR 0.29 0.016 3.60 100 YR 0.48 0.027 6.22 322-434 X-Site Printed 6/17/2022Prepared by CEC Page 2HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.013 61 Grass, B (X-N) 0.088 96 Gravel (X-N) 0.133 98 Impervious (X-N, X-S) 0.234 95 TOTAL AREA Type II 24-hr 2 YR Rainfall=2.90"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 6HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-N: Existing to North Runoff = 0.69 cfs @ 11.95 hrs, Volume= 0.034 af, Depth= 2.25" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YR Rainfall=2.90" Area (ac) CN Description * 0.013 61 Grass, B * 0.081 98 Impervious * 0.088 96 Gravel 0.182 94 Weighted Average 0.101 55.49% Pervious Area 0.081 44.51% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-N: Existing to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 2 YR Rainfall=2.90" Runoff Area=0.182 ac Runoff Volume=0.034 af Runoff Depth=2.25" Tc=5.0 min CN=94 0.69 cfs Type II 24-hr 2 YR Rainfall=2.90"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 7HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-S: Existing to South Runoff = 0.21 cfs @ 11.95 hrs, Volume= 0.012 af, Depth= 2.67" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YR Rainfall=2.90" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-S: Existing to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 2 YR Rainfall=2.90" Runoff Area=0.052 ac Runoff Volume=0.012 af Runoff Depth=2.67" Tc=5.0 min CN=98 0.21 cfs Type II 24-hr 10 YR Rainfall=3.83"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 9HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-N: Existing to North Runoff = 0.94 cfs @ 11.95 hrs, Volume= 0.048 af, Depth= 3.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YR Rainfall=3.83" Area (ac) CN Description * 0.013 61 Grass, B * 0.081 98 Impervious * 0.088 96 Gravel 0.182 94 Weighted Average 0.101 55.49% Pervious Area 0.081 44.51% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-N: Existing to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type II 24-hr 10 YR Rainfall=3.83" Runoff Area=0.182 ac Runoff Volume=0.048 af Runoff Depth=3.16" Tc=5.0 min CN=94 0.94 cfs Type II 24-hr 10 YR Rainfall=3.83"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 10HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-S: Existing to South Runoff = 0.29 cfs @ 11.95 hrs, Volume= 0.016 af, Depth= 3.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YR Rainfall=3.83" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-S: Existing to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type II 24-hr 10 YR Rainfall=3.83" Runoff Area=0.052 ac Runoff Volume=0.016 af Runoff Depth=3.60" Tc=5.0 min CN=98 0.29 cfs Type II 24-hr 100 YR Rainfall=6.46"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 12HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-N: Existing to North Runoff = 1.66 cfs @ 11.95 hrs, Volume= 0.087 af, Depth= 5.75" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YR Rainfall=6.46" Area (ac) CN Description * 0.013 61 Grass, B * 0.081 98 Impervious * 0.088 96 Gravel 0.182 94 Weighted Average 0.101 55.49% Pervious Area 0.081 44.51% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-N: Existing to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type II 24-hr 100 YR Rainfall=6.46" Runoff Area=0.182 ac Runoff Volume=0.087 af Runoff Depth=5.75" Tc=5.0 min CN=94 1.66 cfs Type II 24-hr 100 YR Rainfall=6.46"322-434 X-Site Printed 6/17/2022Prepared by CEC Page 13HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment X-S: Existing to South Runoff = 0.48 cfs @ 11.95 hrs, Volume= 0.027 af, Depth= 6.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YR Rainfall=6.46" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment X-S: Existing to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100 YR Rainfall=6.46" Runoff Area=0.052 ac Runoff Volume=0.027 af Runoff Depth=6.22" Tc=5.0 min CN=98 0.48 cfs APPENDIX F PROPOSED HYDROCAD OUTPUT P-N Proposed to North P-S Proposed to South Routing Diagram for 322-434 P-Site Prepared by CEC, Printed 9/14/2022 HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 100 YR Rainfall=6.46"322-434 P-Site Printed 9/14/2022Prepared by CEC HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Events for Subcatchment P-N: Proposed to North Event Runoff (cfs) Volume (acre-feet) Depth (inches) 2 YR 0.60 0.029 1.89 10 YR 0.86 0.042 2.76 100 YR 1.58 0.080 5.29 Type II 24-hr 100 YR Rainfall=6.46"322-434 P-Site Printed 9/13/2022Prepared by CEC HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Events for Subcatchment P-S: Proposed to South Event Runoff (cfs) Volume (acre-feet) Depth (inches) 2 YR 0.21 0.012 2.67 10 YR 0.29 0.016 3.60 100 YR 0.48 0.027 6.22 322-434 P-Site Printed 9/14/2022Prepared by CEC Page 2HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 0.039 61 Grass, B (P-N) 0.194 98 Impervious (P-N, P-S) 0.233 92 TOTAL AREA Type II 24-hr 2 YR Rainfall=2.90"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 3HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-N: Proposed to North Runoff = 0.60 cfs @ 11.95 hrs, Volume= 0.029 af, Depth= 1.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YR Rainfall=2.90" Area (ac) CN Description * 0.039 61 Grass, B * 0.142 98 Impervious 0.181 90 Weighted Average 0.039 21.55% Pervious Area 0.142 78.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-N: Proposed to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 2 YR Rainfall=2.90" Runoff Area=0.181 ac Runoff Volume=0.029 af Runoff Depth=1.89" Tc=5.0 min CN=90 0.60 cfs Type II 24-hr 2 YR Rainfall=2.90"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 4HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-S: Proposed to South Runoff = 0.21 cfs @ 11.95 hrs, Volume= 0.012 af, Depth= 2.67" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 2 YR Rainfall=2.90" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-S: Proposed to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Type II 24-hr 2 YR Rainfall=2.90" Runoff Area=0.052 ac Runoff Volume=0.012 af Runoff Depth=2.67" Tc=5.0 min CN=98 0.21 cfs Type II 24-hr 10 YR Rainfall=3.83"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 5HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-N: Proposed to North Runoff = 0.86 cfs @ 11.95 hrs, Volume= 0.042 af, Depth= 2.76" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YR Rainfall=3.83" Area (ac) CN Description * 0.039 61 Grass, B * 0.142 98 Impervious 0.181 90 Weighted Average 0.039 21.55% Pervious Area 0.142 78.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-N: Proposed to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 10 YR Rainfall=3.83" Runoff Area=0.181 ac Runoff Volume=0.042 af Runoff Depth=2.76" Tc=5.0 min CN=90 0.86 cfs Type II 24-hr 10 YR Rainfall=3.83"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 6HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-S: Proposed to South Runoff = 0.29 cfs @ 11.95 hrs, Volume= 0.016 af, Depth= 3.60" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 10 YR Rainfall=3.83" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-S: Proposed to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Type II 24-hr 10 YR Rainfall=3.83" Runoff Area=0.052 ac Runoff Volume=0.016 af Runoff Depth=3.60" Tc=5.0 min CN=98 0.29 cfs Type II 24-hr 100 YR Rainfall=6.46"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 7HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-N: Proposed to North Runoff = 1.58 cfs @ 11.95 hrs, Volume= 0.080 af, Depth= 5.29" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YR Rainfall=6.46" Area (ac) CN Description * 0.039 61 Grass, B * 0.142 98 Impervious 0.181 90 Weighted Average 0.039 21.55% Pervious Area 0.142 78.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-N: Proposed to North Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)1 0 Type II 24-hr 100 YR Rainfall=6.46" Runoff Area=0.181 ac Runoff Volume=0.080 af Runoff Depth=5.29" Tc=5.0 min CN=90 1.58 cfs Type II 24-hr 100 YR Rainfall=6.46"322-434 P-Site Printed 9/14/2022Prepared by CEC Page 8HydroCAD® 10.00-20 s/n 03107 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment P-S: Proposed to South Runoff = 0.48 cfs @ 11.95 hrs, Volume= 0.027 af, Depth= 6.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.05 hrs Type II 24-hr 100 YR Rainfall=6.46" Area (ac) CN Description * 0.052 98 Impervious 0.052 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P-S: Proposed to South Runoff Hydrograph Time (hours) 484644424038363432302826242220181614121086420Flow (cfs)0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Type II 24-hr 100 YR Rainfall=6.46" Runoff Area=0.052 ac Runoff Volume=0.027 af Runoff Depth=6.22" Tc=5.0 min CN=98 0.48 cfs