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HomeMy WebLinkAboutDrainage ReportDrainage Calculations Tom Wood Audi Service Addition 4610 East 96th Street Carmel, Indiana Prepared for: Tom Wood, Inc. Job #: TWI.013 Date: 05/26/23 REV: 10/04/23 Prepared by: Roger C. Ward, Jr. PE 6555 Carrollton Avenue Indianapolis, IN 46220 (317) 251-1738 (Fax) 251-1923 02/22/2023 Walker Professional Insurance PO BOX 55 Carmel IN 46082 Holly Gill-Gaither (317) 759-9321 Certificate@WalkerProfessional.com Roger Ward Engineering, Inc. 6555 Carrollton Ave. Indianapolis IN 46220 Berkley Insurance Company 32603 22-23 Master A Professional LIability Claims Made Form AEC-9062121-02 12/09/2022 12/09/2023 Per Claim Limit $2,000,000 Aggregate Limit $2,000,000 30 days notice of cancellation, except for non-payment, shall be provided to the certificate holder. Waiver of subrogation is provided on the Professional Liability policy in favor of the insured’s client only if required by written contract. SHOULD ANY OF THE ABOVE DESCRIBED POLICIES BE CANCELLED BEFORE THE EXPIRATION DATE THEREOF, NOTICE WILL BE DELIVERED IN ACCORDANCE WITH THE POLICY PROVISIONS. INSURER(S) AFFORDING COVERAGE INSURER F : INSURER E : INSURER D : INSURER C : INSURER B : INSURER A : NAIC # NAME:CONTACT (A/C, No):FAX E-MAILADDRESS: PRODUCER (A/C, No, Ext):PHONE INSURED REVISION NUMBER:CERTIFICATE NUMBER:COVERAGES IMPORTANT: If the certificate holder is an ADDITIONAL INSURED, the policy(ies) must have ADDITIONAL INSURED provisions or be endorsed. If SUBROGATION IS WAIVED, subject to the terms and conditions of the policy, certain policies may require an endorsement. A statement on this certificate does not confer rights to the certificate holder in lieu of such endorsement(s). THIS CERTIFICATE IS ISSUED AS A MATTER OF INFORMATION ONLY AND CONFERS NO RIGHTS UPON THE CERTIFICATE HOLDER. THIS CERTIFICATE DOES NOT AFFIRMATIVELY OR NEGATIVELY AMEND, EXTEND OR ALTER THE COVERAGE AFFORDED BY THE POLICIES BELOW. THIS CERTIFICATE OF INSURANCE DOES NOT CONSTITUTE A CONTRACT BETWEEN THE ISSUING INSURER(S), AUTHORIZED REPRESENTATIVE OR PRODUCER, AND THE CERTIFICATE HOLDER. OTHER: (Per accident) (Ea accident) $ $ N / A SUBR WVD ADDL INSD THIS IS TO CERTIFY THAT THE POLICIES OF INSURANCE LISTED BELOW HAVE BEEN ISSUED TO THE INSURED NAMED ABOVE FOR THE POLICY PERIOD INDICATED. NOTWITHSTANDING ANY REQUIREMENT, TERM OR CONDITION OF ANY CONTRACT OR OTHER DOCUMENT WITH RESPECT TO WHICH THIS CERTIFICATE MAY BE ISSUED OR MAY PERTAIN, THE INSURANCE AFFORDED BY THE POLICIES DESCRIBED HEREIN IS SUBJECT TO ALL THE TERMS, EXCLUSIONS AND CONDITIONS OF SUCH POLICIES. LIMITS SHOWN MAY HAVE BEEN REDUCED BY PAID CLAIMS. $ $ $ $PROPERTY DAMAGE BODILY INJURY (Per accident) BODILY INJURY (Per person) COMBINED SINGLE LIMIT AUTOS ONLY AUTOSAUTOS ONLY NON-OWNED SCHEDULEDOWNED ANY AUTO AUTOMOBILE LIABILITY Y / N WORKERS COMPENSATION AND EMPLOYERS' LIABILITY OFFICER/MEMBER EXCLUDED? (Mandatory in NH) DESCRIPTION OF OPERATIONS below If yes, describe under ANY PROPRIETOR/PARTNER/EXECUTIVE $ $ $ E.L. DISEASE - POLICY LIMIT E.L. DISEASE - EA EMPLOYEE E.L. EACH ACCIDENT EROTH-STATUTEPER LIMITS(MM/DD/YYYY)POLICY EXP(MM/DD/YYYY)POLICY EFFPOLICY NUMBERTYPE OF INSURANCELTRINSR DESCRIPTION OF OPERATIONS / LOCATIONS / VEHICLES (ACORD 101, Additional Remarks Schedule, may be attached if more space is required) EXCESS LIAB UMBRELLA LIAB $EACH OCCURRENCE $AGGREGATE $ OCCUR CLAIMS-MADE DED RETENTION $ $PRODUCTS - COMP/OP AGG $GENERAL AGGREGATE $PERSONAL & ADV INJURY $MED EXP (Any one person) $EACH OCCURRENCE DAMAGE TO RENTED $PREMISES (Ea occurrence) COMMERCIAL GENERAL LIABILITY CLAIMS-MADE OCCUR GEN'L AGGREGATE LIMIT APPLIES PER: POLICY PRO-JECT LOC CERTIFICATE OF LIABILITY INSURANCE DATE (MM/DD/YYYY) CANCELLATION AUTHORIZED REPRESENTATIVE ACORD 25 (2016/03) © 1988-2015 ACORD CORPORATION. All rights reserved. CERTIFICATE HOLDER The ACORD name and logo are registered marks of ACORD HIRED AUTOS ONLY TABLE OF CONTENTS Section I: Report A. Project Title B. Project Description C. Design Method and Criteria D. References E. Existing Conditions F. Proposed Conditions G. Stormwater Quality and BMP Recommendations Section II: Appendix A. Site Information (maps, exhibits, etc.) B. Existing Conditions C. Proposed Conditions D. Stormwater Quality Data E. Tom Wood Audi Drainage Report 05-06-14 SECTION I: REPORT A. Project Title Tom Wood Audi Service Addition B. Project Description This project is located east of the intersection of 96th Street and Randall Drive in Carmel, Indiana. The site is on the north side of 96th Street. The overall site is approximately +/- 4.61 acres. However, only approximately +/- 0.83 acres will be disturbed. The existing site is already developed as a car dealership. The site is mostly roof top and asphalt parking areas, with some grass areas along the east and west sides of the property. The existing building and the parking area immediately around the building drain into an on-site storm sewer and underground detention chamber system before the stormwater is released and discharged into Carmel Creek. From there, the stormwater eventually makes its way to the White River, the ultimate receiving waters for the site. The proposed development will consist of a building expansion for the vehicle service department of the dealership. Since approximately +/- 0.83 acres of land will be disturbed (which is above Carmel’s ¼-acre threshold), the drainage from the building addition’s roof and immediately surrounding parking area will be collected and sent to the underground detention facility. To account for the additional improvements, an additional two (2) rows or twenty-six (26) chambers will be installed next to the existing system. And the release rates from the detention facility will be at or below the allowed discharges under the redevelopment scenario. The existing land uses adjacent to the site are as follows: North: Commercial West: Commercial South: Commercial East: Commercial C. Design Method and Criteria 1. Soil Type: Soil maps from the United States Department of Agriculture, Soil Conservation Service, identify Westland silty clay loam (We - 40% site) and Sleeth loam (St – 60% site). The Westland soils are classified as type “B/D” soils, and they consist of deep, very poorly drained, slowly permeable soils on broad terraces. The Sleeth soils are classified as type “C” soils, and they consist of deep, somewhat poorly drained, moderately permeable soils on terraces. 2. Design Storm: The 2-year, 10-year, and 100-year storm events have been analyzed for the existing & proposed condition. The NRCS type-II 24-hour distribution was used in the calculations. 3. Overall Watershed: Carmel Creek => White River. D. References 1. TR55 Stormwater Design Manual. 2. Hamilton County Soil Survey. 3. HydroCAD Software E. Existing Conditions The existing site is already developed as a car dealership. The site is mostly roof top and asphalt parking areas, with some grass areas along the east and west sides of the property. The existing building and the parking area immediately around the building drain into an on-site storm sewer and underground detention chamber system before the stormwater is released and discharged into Carmel Creek. From there, the stormwater eventually makes its way to the White River, the ultimate receiving waters for the site. The overall existing site is approximately +/- 4.61 acres; however, only approximately +/- 0.83 acres will be disturbed / redeveloped for the service building addition. Back in 2014, the Audi dealership was renovated and expanded. At that time, the new drainage area that was captured and sent into the detention system was 1.43 acres. Today, we are proposing to capture an additional 0.28 acres for a total area of 1.71 acres. For calculation purposes, basin EX1 will represent the 1.71 acres being captured. Basin EX2 (0.24 acres) will represent the area within the disturbed area that will not be captured and allowed to sheet drain toward Carmel Creek as it currently does in the existing condition. The following are the computed 2-year, 10-year and 100-year runoff rates for the on-site basins utilizing the NRCS type-II 24-hour storm event, as computed by HydroCAD. Existing On-site Basins EX1 EX2 2-year runoff 6.20 cfs 0.77 cfs 10-year runoff 9.08 cfs 1.19 cfs 100-year runoff 15.50 cfs 2.14 cfs Allowed Discharge Based Upon Redevelopment Scenario For the overall drainage area being captured (EX1), the allowed discharges for the corresponding proposed drainage area being captured (PR1) will be: 10-year proposed <= 2-year existing = 6.20 cfs 100-year proposed <= 10-year existing = 9.08 cfs F. Proposed Conditions The proposed development will consist of a building expansion for the vehicle service department of the dealership. Since approximately +/- 0.83 acres of land will be disturbed (which is above Carmel’s ¼-acre threshold), the drainage from the building addition’s roof and immediately surrounding parking lot will be collected and sent to the underground detention facility. The total area being captured and being sent to the existing underground detention system is 1.71 acres and is labelled as PR1. To account for the additional improvements, an additional two (2) rows or twenty-six (26) chambers will be installed next to the existing system. And the release rates from the detention facility will be at or below the allowed discharges under the redevelopment scenario. Basin PR2 (0.24 acres) will represent the area within the disturbed area that will not be captured and allowed to sheet drain toward Carmel Creek as it currently does in the existing condition. The following are the computed 2-year, 10-year and 100-year runoff and discharge rates for the on-site basins utilizing the NRCS type-II 24-hour storm event, as computed by HydroCAD. Proposed On-site Basins (before detention) PR1 PR2 2-year runoff 6.22 cfs 0.91 cfs 10-year runoff 9.03 cfs 1.32 cfs 100-year runoff 15.32 cfs 2.24 cfs Proposed On-site Basin (after detention) PR1 2-year proposed = 3.41 cfs 10-year proposed = 5.21 cfs < 6.20 cfs 100-year proposed = 8.22 cfs < 9.08 cfs. G.Stormwater Quality and BMP Recommendations According to Chapter 7, section 701 of the City of Carmel Stormwater Management Ordinance, any project that disturbs ¼ acre or more of land is required to provide two (2) post-construction stormwater quality measures. The proposed development will disturb approximately +/- 0.83 acres. The total drainage area being captured is 1.71 acres and will drain into an existing (1) Storm Drain Insert and one (1) infiltration trench. 1.We are proposing to replace the existing Aqua-Swirl AS-4 On-Line model (storm drain insert) located just east of the existing building in the front parking lot labeled as BMP 101, with a new Aqua-Swirl XC-7 to handle the increased water quality volume and to pass the 10-year flow rate without backing up through the structure. 2.We are also proposing to use the existing StormTech Isolator Row (infiltration trench) within the underground detention system. SECTION II: APPENDIX A. SITE INFORMATION 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 5/17/2022 at 9:59 AM 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°5'53"W 39°56'2"N 86°5'16"W 39°55'34"N Basemap: USGS National Map: Orthoimagery: Data refreshed October, 2020 B. EXISTING CONDITIONS Runoff Curve Coefficient Number Roof Area = 0.90 98 Impervious Area = 0.85 98 Greenspace = 0.20 80 **Open Space (Good Condition - PROPOSED) Greenspace = 0.20 69 **Open Space (Good Condition - EXISTING) Gravel/Stone = 0.85 85 Type 'D' Soils - For Proposed Condition Type 'B' & 'C' Soils - For Existing Condition OVERALL (PR1) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 73988 477 0 74465 1.71 0.88 98 DIRECT (PR2) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 10141 156 0 10297 0.24 0.84 98 OVERALL (EX1) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 72255 683 1527 74465 1.71 0.84 97 DIRECT (EX2) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 8180 2089 28 10297 0.24 0.72 92 Time of Concentration WorksheetPROJECT: TOM WOOD AUDI SERVICE Based on TR-55JOB #: TWI.013Typical values for Manning's nTypical values for Manning's nOverland Flow 2 year, 24 hour rainfall =2.64inches Channel Flow short grass 0.150 grass 0.030 dense grass 0.240 concrete 0.015 pavement 0.011 rip-rap 0.035 Overland flowseg. 1 Overland flowseg. 2 Shallow Concentrated Flow Channel FlowBasin Length S n T_t Length S n T_t Length SPaved/UnVel. T_t Length a Pw r S n Vel. T_tT_cname (ft) % (min) (ft) % (min) (ft) % (P or U) (ft/s) (min) (ft) (s.f.) (ft) (ft) % (ft/s) (min)(min)202 47 1.00 0.01115P ROOF90 2.00 0.0111283 0.35 2.090.170.53 0.0131.17 45201 68 1.00 0.01115108 100 0.70 0.011249 0.70 P1.70 051075E ROOF65 2.00 0.0111344 0.55 2.620.210.50 0.0131.32 4510651035102 63 0.70 0.011151015101B5PR1 10 1.00 0.150290 1.00 0.011235 1.00 P2.03 0150 0.79 3.140.250.31 0.0131.18 26.3PR2 72 2.80 0.01115EX1 10 1.00 0.150290 1.00 0.011235 1.00 P2.03 0100 0.79 3.140.250.31 0.0131.18 15.6EX2 72 2.80 0.01115Page 1 EX1 Overall Existing Basin EX2 Existing Basin Not Detained PR1 Proposed Captured Basin PR2 Proposed Basin Not Detained 1P Underground Detention Routing Diagram for TW Audi HydroCAD Proposed Prepared by {enter your company name here}, Printed 5/31/2023 HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX1: Overall Existing Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Type II 24-hr 2yr-24hr Rainfall=2.66" Runoff Area=1.710 ac Runoff Volume=0.309 af Runoff Depth>2.17" Tc=5.6 min CN=97 6.20 cfs Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX1: Overall Existing Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10yr-24hr Rainfall=3.83" Runoff Area=1.710 ac Runoff Volume=0.461 af Runoff Depth>3.23" Tc=5.6 min CN=97 9.08 cfs Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX1: Overall Existing Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 100yr-24hr Rainfall=6.46" Runoff Area=1.710 ac Runoff Volume=0.800 af Runoff Depth>5.62" Tc=5.6 min CN=97 15.50 cfs Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX2: Existing Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)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 2yr-24hr Rainfall=2.66" Runoff Area=0.240 ac Runoff Volume=0.034 af Runoff Depth>1.72" Tc=5.0 min CN=92 0.77 cfs Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX2: Existing Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 10yr-24hr Rainfall=3.83" Runoff Area=0.240 ac Runoff Volume=0.055 af Runoff Depth>2.77" Tc=5.0 min CN=92 1.19 cfs Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed Printed 5/31/2023Prepared by {enter your company name here} HydroCAD® 10.00-26 s/n 08404 © 2020 HydroCAD Software Solutions LLC Subcatchment EX2: Existing Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 100yr-24hr Rainfall=6.46" Runoff Area=0.240 ac Runoff Volume=0.103 af Runoff Depth>5.17" Tc=5.0 min CN=92 2.14 cfs C. PROPOSED CONDITIONS ROGER WARD ENGINEERING, INC.STORM DRAIN FLOW TABULATION FORM - RATIONAL METHODPROJECT NAMETOM WOOD AUDI SERVICEPROJECT No. TWI.013 COMPUTED BY:RCWSTORM FREQUENCY DESIGN YEAR 10CHECKED BY:RCWC A L C U L A T E D D E S I G N / A S - B U I L TLOCATION INLET ACRES COEF. SUM TIME CONC. (min) INT. "Q" = PIPE (full) n =0.013Pipe Pipe Max Q Max V MANHOLEfrom to AREA sub total "C" CA CA inlet drain total "I" CIA size slope vel. length slope full full INV out INV in2020.05 0.810.0455 6.98 0.29T.C.=740.34202 2010.05 0.04 5.00 0.30 5.30 6.98 0.29120.01 0.3651 0.402.25 2.87 735.89 735.69P ROOF0.32 0.900.2955 6.89 2.00T.C.=741.00P ROOF 2010.32 0.29 5.24 1.88 7.12 6.89 2.0082.74 5.73283 0.530.88 2.51 737.10 735.612010.10 0.850.0855 6.98 0.57T.C.=740.20201 1030.47 0.41 7.12 0.23 7.35 6.24 2.58120.52 3.2946 0.552.64 3.36 735.59 735.331080.30 0.850.2655 6.98 1.80T.C.=738.68108 1070.30 0.26 5.00 0.21 5.21 6.98 1.80120.25 2.2933 0.342.08 2.64 735.20 735.091070.07 0.850.0655 6.98 0.43T.C.=739.58107 1060.38 0.32 5.21 0.67 5.87 6.90 2.21120.38 2.81116 0.412.28 2.90 735.08 734.60E ROOF0.77 0.900.6955 6.87 4.75T.C.=741.04E ROOF 1060.77 0.69 5.29 1.66 6.94 6.87 4.75815.43 13.61344 1.001.21 3.46 738.69 735.251060.00 0.000.0055 6.98 0.00T.C.=740.18106 1031.15 1.01 6.94 0.08 7.03 6.30 6.37180.37 3.6025 0.728.91 5.04 734.59 734.411030.00 0.000.0055 6.98 0.00T.C.=740.13103 1021.62 1.42 7.03 0.09 7.12 6.27 8.93180.72 5.0628 0.728.91 5.04 733.91 733.711020.09 0.850.0855 6.98 0.56T.C.=739.54102 1011.71 1.50 7.12 0.02 7.14 6.24 9.39180.80 5.328 1.2011.50 6.51 733.53 733.431010.00 0.000.0055 6.98 0.00T.C.=739.71101 101A1.71 1.50 7.14 0.02 7.16 6.24 9.38180.80 5.318 1.2011.50 6.51 733.33 733.24101B0.00 0.000.0055 6.98 0.00T.C.=738.93101B EX2071.71 1.50 7.16 0.15 7.31 6.23 9.37152.10 7.6434 0.504.57 3.72 733.24 733.0710/04/23Page 1 Inlet Capacity Calculations - Sag Inlet SINGLE INLET 201 Inlet Type = Neenah R-3405 A = 1.50 ft - Assuming 50% Clogged = 0.75 ft P = 7.90 ft - Assuming 50% Clogged = 3.95 ft Q = 0.57 cfs - Allowable Flow to Controlling Inlet SINGLE INLET SINGLE INLET Orifice Flow Weir Flow Q = 4.89 * A * (d)^0.5 Q = 3.0 * P * (d)^1.5 Q = Flow in cfs Q = Flow in cfs A = Open area of inlet in ft^2 P = Wetted perimeter of inlet in ft d = Depth of water above inlet in inches d = Depth of water above inlet in inches d = 0.02 ft. d = 0.13 ft. SINGLE INLET 202 Inlet Type = Neenah R-2502-D A = 0.90 ft - Assuming 50% Clogged = 0.45 ft P = 6.00 ft - Assuming 50% Clogged = 3.00 ft Q = 0.29 cfs - Allowable Flow to Controlling Inlet SINGLE INLET SINGLE INLET Orifice Flow Weir Flow Q = 4.89 * A * (d)^0.5 Q = 3.0 * P * (d)^1.5 Q = Flow in cfs Q = Flow in cfs A = Open area of inlet in ft^2 P = Wetted perimeter of inlet in ft d = Depth of water above inlet in inches d = Depth of water above inlet in inches d = 0.02 ft. d = 0.10 ft. Runoff Curve Coefficient Number Roof Area = 0.90 98 Impervious Area = 0.85 98 Greenspace = 0.20 80 **Open Space (Good Condition - PROPOSED) Greenspace = 0.20 69 **Open Space (Good Condition - EXISTING) Gravel/Stone = 0.85 85 Type 'D' Soils - For Proposed Condition Type 'B' & 'C' Soils - For Existing Condition BASIN (202) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 2063 151 0 2214 0.05 0.81 97 BASIN (P ROOF) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 14058 0 0 14058 0.32 0.90 98 BASIN (201) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 4203 0 0 4203 0.10 0.85 98 BASIN (108) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 13177 80 0 13257 0.30 0.85 98 BASIN (107) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 3189 0 0 3189 0.07 0.85 98 BASIN (E ROOF) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 33446 0 0 33446 0.77 0.90 98 BASIN (102) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 3853 246 0 4099 0.09 0.81 97 Runoff Curve Coefficient Number Roof Area = 0.90 98 Impervious Area = 0.85 98 Greenspace = 0.20 80 **Open Space (Good Condition - PROPOSED) Greenspace = 0.20 69 **Open Space (Good Condition - EXISTING) Gravel/Stone = 0.85 85 Type 'D' Soils - For Proposed Condition Type 'B' & 'C' Soils - For Existing Condition OVERALL (PR1) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 73988 477 0 74465 1.71 0.88 98 DIRECT (PR2) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 10141 156 0 10297 0.24 0.84 98 OVERALL (EX1) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 72255 683 1527 74465 1.71 0.84 97 DIRECT (EX2) Impervious Area Greenspace Stone Total Total Composite Composite (ft^2) (ft^2) (ft^2) (ft^2) (Acres) "C" "CN" 8180 2089 28 10297 0.24 0.72 92 Time of Concentration WorksheetPROJECT: TOM WOOD AUDI SERVICE Based on TR-55JOB #: TWI.013Typical values for Manning's nTypical values for Manning's nOverland Flow 2 year, 24 hour rainfall =2.64inches Channel Flow short grass 0.150 grass 0.030 dense grass 0.240 concrete 0.015 pavement 0.011 rip-rap 0.035 Overland flowseg. 1 Overland flowseg. 2 Shallow Concentrated Flow Channel FlowBasin Length S n T_t Length S n T_t Length SPaved/UnVel. T_t Length a Pw r S n Vel. T_tT_cname (ft) % (min) (ft) % (min) (ft) % (P or U) (ft/s) (min) (ft) (s.f.) (ft) (ft) % (ft/s) (min)(min)202 47 1.00 0.01115P ROOF90 2.00 0.0111283 0.35 2.090.170.53 0.0131.17 45201 68 1.00 0.01115108 100 0.70 0.011249 0.70 P1.70 051075E ROOF65 2.00 0.0111344 0.55 2.620.210.50 0.0131.32 4510651035102 63 0.70 0.011151015101B5PR1 10 1.00 0.150290 1.00 0.011235 1.00 P2.03 0150 0.79 3.140.250.31 0.0131.18 26.3PR2 72 2.80 0.01115EX1 10 1.00 0.150290 1.00 0.011235 1.00 P2.03 0100 0.79 3.140.250.31 0.0131.18 15.6EX2 72 2.80 0.01115Page 1 1P Underground Detention PR1 Proposed Captured Basin PR2 Proposed Basin Not Detained Routing Diagram for TW Audi HydroCAD Proposed As-Built Prepared by Roger Ward Engineering, Printed 8/7/2023 HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Subcat Reach Pond Link As-Built Proposed Condition Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 2HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Underground Detention Inflow Area = 1.710 ac,100.00% Impervious, Inflow Depth > 2.25" for 2yr-24hr event Inflow = 6.15 cfs @ 11.97 hrs, Volume= 0.321 af Outflow = 3.41 cfs @ 12.06 hrs, Volume= 0.295 af, Atten= 44%, Lag= 5.8 min Primary = 3.41 cfs @ 12.06 hrs, Volume= 0.295 af Routing by Dyn-Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 733.98' @ 12.06 hrs Surf.Area= 0.135 ac Storage= 0.115 af Plug-Flow detention time= 79.9 min calculated for 0.294 af (91% of inflow) Center-of-Mass det. time= 49.8 min ( 785.0 - 735.2 ) Volume Invert Avail.Storage Storage Description #1A 732.64' 0.128 af 61.75'W x 95.00'L x 3.50'H Field A 0.471 af Overall - 0.152 af Embedded = 0.320 af x 40.0% Voids #2A 733.14' 0.152 af ADS_StormTech SC-740 x 143 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 11 rows 0.279 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 733.01'15.0" Round Culvert L= 35.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 733.01' / 732.66' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=3.37 cfs @ 12.06 hrs HW=733.98' (Free Discharge) 1=Culvert (Barrel Controls 3.37 cfs @ 4.57 fps) As-Built Proposed Condition Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 3HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Pond 1P: Underground Detention Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Inflow Area=1.710 ac Peak Elev=733.98' Storage=0.115 af 15.0" Round Culvert n=0.013 L=35.0' S=0.0100 '/' 6.15 cfs 3.41 cfs As-Built Proposed Condition Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 4HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: Proposed Captured Basin Runoff = 6.15 cfs @ 11.97 hrs, Volume= 0.321 af, Depth> 2.25" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2yr-24hr Rainfall=2.66" Area (ac) CN Description * 1.710 98 1.710 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 Direct Entry, Subcatchment PR1: Proposed Captured Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)6 5 4 3 2 1 0 Type II 24-hr 2yr-24hr Rainfall=2.66" Runoff Area=1.710 ac Runoff Volume=0.321 af Runoff Depth>2.25" Tc=6.3 min CN=98 6.15 cfs As-Built Proposed Condition Type II 24-hr 2yr-24hr Rainfall=2.66"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 5HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Proposed Basin Not Detained Runoff = 0.91 cfs @ 11.95 hrs, Volume= 0.045 af, Depth> 2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 2yr-24hr Rainfall=2.66" Area (ac) CN Description * 0.240 98 0.240 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR2: Proposed Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 2yr-24hr Rainfall=2.66" Runoff Area=0.240 ac Runoff Volume=0.045 af Runoff Depth>2.26" Tc=5.0 min CN=98 0.91 cfs As-Built Proposed Condition Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 6HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Underground Detention Inflow Area = 1.710 ac,100.00% Impervious, Inflow Depth > 3.31" for 10yr-24hr event Inflow = 8.93 cfs @ 11.97 hrs, Volume= 0.472 af Outflow = 5.21 cfs @ 12.06 hrs, Volume= 0.444 af, Atten= 42%, Lag= 5.5 min Primary = 5.21 cfs @ 12.06 hrs, Volume= 0.444 af Routing by Dyn-Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 734.32' @ 12.06 hrs Surf.Area= 0.135 ac Storage= 0.148 af Plug-Flow detention time= 65.5 min calculated for 0.442 af (94% of inflow) Center-of-Mass det. time= 41.6 min ( 773.6 - 732.0 ) Volume Invert Avail.Storage Storage Description #1A 732.64' 0.128 af 61.75'W x 95.00'L x 3.50'H Field A 0.471 af Overall - 0.152 af Embedded = 0.320 af x 40.0% Voids #2A 733.14' 0.152 af ADS_StormTech SC-740 x 143 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 11 rows 0.279 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 733.01'15.0" Round Culvert L= 35.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 733.01' / 732.66' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=5.17 cfs @ 12.06 hrs HW=734.31' (Free Discharge) 1=Culvert (Barrel Controls 5.17 cfs @ 5.02 fps) As-Built Proposed Condition Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 7HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Pond 1P: Underground Detention Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.710 ac Peak Elev=734.32' Storage=0.148 af 15.0" Round Culvert n=0.013 L=35.0' S=0.0100 '/' 8.93 cfs 5.21 cfs As-Built Proposed Condition Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 8HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: Proposed Captured Basin Runoff = 8.93 cfs @ 11.97 hrs, Volume= 0.472 af, Depth> 3.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10yr-24hr Rainfall=3.83" Area (ac) CN Description * 1.710 98 1.710 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 Direct Entry, Subcatchment PR1: Proposed Captured Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 10yr-24hr Rainfall=3.83" Runoff Area=1.710 ac Runoff Volume=0.472 af Runoff Depth>3.31" Tc=6.3 min CN=98 8.93 cfs As-Built Proposed Condition Type II 24-hr 10yr-24hr Rainfall=3.83"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 9HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Proposed Basin Not Detained Runoff = 1.32 cfs @ 11.95 hrs, Volume= 0.066 af, Depth> 3.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 10yr-24hr Rainfall=3.83" Area (ac) CN Description * 0.240 98 0.240 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR2: Proposed Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)1 0 Type II 24-hr 10yr-24hr Rainfall=3.83" Runoff Area=0.240 ac Runoff Volume=0.066 af Runoff Depth>3.31" Tc=5.0 min CN=98 1.32 cfs As-Built Proposed Condition Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 10HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Pond 1P: Underground Detention Inflow Area = 1.710 ac,100.00% Impervious, Inflow Depth > 5.68" for 100yr-24hr event Inflow = 15.15 cfs @ 11.97 hrs, Volume= 0.810 af Outflow = 8.22 cfs @ 12.06 hrs, Volume= 0.776 af, Atten= 46%, Lag= 5.9 min Primary = 8.22 cfs @ 12.06 hrs, Volume= 0.776 af Routing by Dyn-Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 735.24' @ 12.06 hrs Surf.Area= 0.135 ac Storage= 0.228 af Plug-Flow detention time= 49.8 min calculated for 0.774 af (96% of inflow) Center-of-Mass det. time= 32.6 min ( 761.8 - 729.1 ) Volume Invert Avail.Storage Storage Description #1A 732.64' 0.128 af 61.75'W x 95.00'L x 3.50'H Field A 0.471 af Overall - 0.152 af Embedded = 0.320 af x 40.0% Voids #2A 733.14' 0.152 af ADS_StormTech SC-740 x 143 Inside #1 Effective Size= 44.6"W x 30.0"H => 6.45 sf x 7.12'L = 45.9 cf Overall Size= 51.0"W x 30.0"H x 7.56'L with 0.44' Overlap Row Length Adjustment= +0.44' x 6.45 sf x 11 rows 0.279 af Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 733.01'15.0" Round Culvert L= 35.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 733.01' / 732.66' S= 0.0100 '/' Cc= 0.900 n= 0.013, Flow Area= 1.23 sf Primary OutFlow Max=8.14 cfs @ 12.06 hrs HW=735.22' (Free Discharge) 1=Culvert (Barrel Controls 8.14 cfs @ 6.63 fps) As-Built Proposed Condition Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 11HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Pond 1P: Underground Detention Inflow Primary Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Inflow Area=1.710 ac Peak Elev=735.24' Storage=0.228 af 15.0" Round Culvert n=0.013 L=35.0' S=0.0100 '/' 15.15 cfs 8.22 cfs As-Built Proposed Condition Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 12HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR1: Proposed Captured Basin Runoff = 15.15 cfs @ 11.97 hrs, Volume= 0.810 af, Depth> 5.68" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100yr-24hr Rainfall=6.46" Area (ac) CN Description * 1.710 98 1.710 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.3 Direct Entry, Subcatchment PR1: Proposed Captured Basin Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Type II 24-hr 100yr-24hr Rainfall=6.46" Runoff Area=1.710 ac Runoff Volume=0.810 af Runoff Depth>5.68" Tc=6.3 min CN=98 15.15 cfs As-Built Proposed Condition Type II 24-hr 100yr-24hr Rainfall=6.46"TW Audi HydroCAD Proposed As-Built Printed 8/7/2023Prepared by Roger Ward Engineering Page 13HydroCAD® 10.00-20 s/n 08404 © 2017 HydroCAD Software Solutions LLC Summary for Subcatchment PR2: Proposed Basin Not Detained Runoff = 2.24 cfs @ 11.95 hrs, Volume= 0.114 af, Depth> 5.68" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type II 24-hr 100yr-24hr Rainfall=6.46" Area (ac) CN Description * 0.240 98 0.240 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment PR2: Proposed Basin Not Detained Runoff Hydrograph Time (hours) 201918171615141312111098765Flow (cfs)2 1 0 Type II 24-hr 100yr-24hr Rainfall=6.46" Runoff Area=0.240 ac Runoff Volume=0.114 af Runoff Depth>5.68" Tc=5.0 min CN=98 2.24 cfs D. STORMWATER QUALITY DATA WQ Water Quality Routing Diagram for Carmel Example Rainfall Prepared by Microsoft, Printed 10/4/2023 HydroCAD® 10.00-19 s/n 08404 © 2016 HydroCAD Software Solutions LLC Subcat Reach Pond Link Type II 24-hr WQ Rainfall=1.00"Carmel Example Rainfall Printed 10/4/2023Prepared by MicrosoftHydroCAD® 10.00-19 s/n 08404 © 2016 HydroCAD Software Solutions LLCSubcatchment WQ: Water QualityRunoffHydrographTime (hours)484644424038363432302826242220181614121086420Flow (cfs)210Type II 24-hrWQ Rainfall=1.00"Runoff Area=1.710 acRunoff Volume=0.142 afRunoff Depth=1.00"Tc=5.0 minCN=1002.53 cfs Type II 24-hr WQ Rainfall=1.00"Carmel Example Rainfall Printed 10/4/2023Prepared by MicrosoftHydroCAD® 10.00-19 s/n 08404 © 2016 HydroCAD Software Solutions LLCSummary for Subcatchment WQ: Water QualityRunoff = 2.53 cfs @ 11.96 hrs, Volume= 0.142 af, Depth= 1.00"Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-48.00 hrs, dt= 0.01 hrsType II 24-hr WQ Rainfall=1.00"Area (ac) CN Description* 1.710 1001.710 100.00% Impervious AreaTc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs)5.0Direct Entry, 06/28/07 Exhibit 701-1: Curve Number Calculation for Water Quality Storm Event Water Quality Curve Number7072747678808284868890929496981000 102030405060708090100Percent ImperviousnessWater Quality Curve Number (CNwq) City of Indianapolis Stormwater Quality Unit (SQU) Selection Guide Pg. 2 0/2022 Version 22 Manufactured SQU SQU System Model Max Treatment Flow (cfs) Max 10-yr On-Line Flow Rate (cfs) Cleanout Depth (Inches) 3-ft 0.85 1.84 9 4-ft 1.5 3.24 9 5-ft 2.35 5.08 9 6-ft 3.38 7.30 9 7-ft 4.60 9.94 9 Hydro International First Defense High Capacity 8-ft 6.00 12.96 9 HS-3 0.50 1.00 6 HS-4 0.88 1.76 6 HS-5 1.37 2.74 6 HS-6 1.98 3.96 6 HS-7 2.69 5.38 6 HS-8 3.52 7.04 6 HS-9 4.45 8.9 6 HS-10 5.49 10.98 6 HS-11 6.65 13.3 6 HydroStorm by Hydroworks, LLC HS-12 7.91 15.82 6 XC-2 0.57 1.16 6 XC-3 1.13 2.30 6 XC-4 1.86 3.79 6 XC-5 2.78 5.66 6 XC-6 3.88 7.90 6 XC-7 5.17 10.52 6 XC-8 6.64 13.51 6 XC-9 8.29 16.87 6 XC-10 10.13 20.62 6 XC-11 12.15 24.73 6 XC-12 14.35 29.20 6 AquaShield Aqua-Swirl Xcelerator1 XC-13 15.53 31.60 6 CS-3 1.02 2.27 9 CS-4 1.80 4.03 9 CS-5 2.81 6.29 9 CS-6 4.05 9.07 9 CS-8 7.20 16.1 9 CS-10 11.3 25.3 9 Contech Cascade Separator CS-12 16.2 36.3 9 10 yr flow rate 9.39 < 10.52 E. AUDI DRAINAGE REPORT 05-06-14 Drainage Calculations Tom Wood Audi 4610 East 96th Street Carmel, Indiana Prepared for: Tom Wood, Inc. c/o Architectural Alliance Job #: AAX.001 Revised: 05/06/14 Prepared by: Roger C. Ward, Jr. PE 7474 Noel Road Indianapolis, IN 46278 (317) 251-1738 (Fax) 251-1923 TABLE OF CONTENTS Section I: Report A. Project Title B. Project Description C. Design Method and Criteria D. References E. Existing Conditions F. Proposed Conditions G. Stormwater Quality and BMP Recommendations Section II: Appendix A. Site Information (maps, exhibits, etc.) B. Existing Conditions C. Proposed Conditions D. Stormwater Quality Data SECTION I: REPORT A. Project Title Tom Wood Audi B. Project Description This project is located east of the intersection of 96th Street and Randall Drive in Carmel, Indiana. The site is on the north side of 96th Street. The overall site is approximately +/- 4.61 acres. However, only approximately +/- 1.43 acres will be disturbed. The existing site is already developed and was used as a car dealership. The site is mostly roof top and asphalt parking areas, with some grass areas along the east and west sides of the property. The existing site mostly sheet drains towards the west to Carmel Creek, with some drainage areas being collected in an on-site storm sewer first, and then discharging into Carmel Creek. From there, the stormwater eventually makes its way to the White River, the ultimate receiving waters for the site. The existing site does lie within the federally designated Flood Zone AE per the Flood Insurance Rate Map (FIRM) #18057C0236F, effective February 19, 2003. However, a more recent flood study was performed by American Structurepoint, Inc. dated November 27, 2013, last revised July 10, 2013. The flood study has been approved by the Indiana Department of Natural Resources (IDNR), and a Letter of Map Revision (LOMR) has been submitted to the Federal Emergency Management Agency (FEMA) for approval. The LOMR greatly reduces the floodplain area for the site, and the study establishes the base flood elevation (BFE) at 740.2 feet for the proposed building renovation. The proposed development will consist of a building renovation and expansion, as well as some site improvements adjacent to the building. The existing buildings west wall, which is closest to Carmel Creek and the floodplain, will not be expanded any further to the west. And the proposed building additions will be located outside of the new floodplain line, as established by the above-mentioned flood study. Since approximately +/- 1.43 acres of land will be disturbed (which is above Carmel’s ¼-acre threshold), the drainage from the building’s roof and immediately surrounding parking lot will be collected, treated for water quality and be detained in an underground detention facility. And the release rates from the detention facility will be at the allowed discharges under the redevelopment scenario. The existing land uses adjacent to the site are as follows: North: Commercial West: Commercial South: Commercial East: Commercial C. Design Method and Criteria 1. Soil Type: Soil maps from the United States Department of Agriculture, Soil Conservation Service, identify Westland silty clay loam (We - 40% site) and Sleeth loam (St – 60% site). The Westland soils are classified as type “B/D” soils, and they consist of deep, very poorly drained, slowly permeable soils on broad terraces. The Sleeth soils are classified as type “C” soils, and they consist of deep, somewhat poorly drained, moderately permeable soils on terraces. 2. Design Storm: The 2-year, 10-year, and 100-year storm events have been analyzed for the existing & proposed condition. The NRCS type-II 24-hour distribution was used in the calculations. 3. Overall Watershed: Carmel Creek => White River. D. References 1. TR55 Stormwater Design Manual. 2. Hamilton County Soil Survey. 3. HydroCAD Software E. Existing Conditions The existing site is already developed and was used as a car dealership. The site is mostly roof top and asphalt parking areas, with some grass areas along the east and west sides of the property. The existing site drains towards Carmel Creek via sheet flow and an on-site storm sewer system. From there, the stormwater eventually makes its way to the White River, the ultimate receiving waters for the site. The overall existing site is approximately +/- 4.61 acres; however, only approximately +/- 1.43 acres will be disturbed / redeveloped. Therefore, for calculation purposes, the 1.43-acre drainage area will be used in the calculations. Since the 1.43-acre basin is all impervious for both the existing and proposed condition, the curve number for both conditions will be 98. The only difference will be the time of concentration (Tc). Since the existing site mostly sheet drains, it will have a Tc = 5 minutes. The following are the computed 2-year and 10-year runoff rates from the on-site basin utilizing the NRCS type-II 24-hour storm event, as computed by HydroCAD. On-site Basin EX – On-site basin. EX - Existing 2-year discharge 5.41 cfs EX - Existing 10-year discharge 7.85 cfs EX - Existing 100-year discharge 13.32 cfs Allowed Discharge Based Upon Existing Conditions A meeting was held on January 9, 2014 with Amanda Foley from the Carmel Engineer’s office. According to Ms. Foley and since the proposed project will be a redevelopment, the allowed discharges under the proposed conditions will be as follows: 10-year proposed <= 2-year existing <= 5.41 cfs 100-year proposed <= 10-year existing <= 7.85 cfs F. Proposed Conditions The proposed development will consist of a building renovation and expansion, as well as some site improvements adjacent to the building. The existing buildings west wall, which is closest to Carmel Creek and the floodplain, will not be expanded any further to the west. And the proposed building additions will be located outside of the new floodplain line, as established by the above-mentioned flood study. Since approximately +/- 1.43 acres of land will be disturbed (which is above Carmel’s ¼-acre threshold), the drainage from the building’s roof and immediately surrounding parking lot will be collected, treated for water quality and be detained in an underground detention facility. And the release rates from the detention facility will be at the allowed discharges under the redevelopment scenario. The following are the computed 2-year and 10-year runoff rates from the on-site basin utilizing the NRCS type-II 24-hour storm event, as computed by HydroCAD. 10-year proposed = 4.49 cfs < 5.41 cfs 100-year proposed = 7.51 cfs < 7.85 cfs. G. Stormwater Quality and BMP Recommendations According to Chapter 7, section 701 of the City of Carmel Stormwater Management Ordinance, any project that disturbs ¼ acre or more of land is required to provide two (2) post-construction stormwater quality measures. The proposed development will disturb approximately +/- 1.43 acres. As part of this development, we are proposing one (1) Storm Drain Insert and one (1) infiltration trench, as labeled on Table 701-1 in Chapter 7. 1. We are proposing the Aqua-Swirl AS-4 On-Line model (storm drain insert) to be located just east of the renovated building in the front parking lot, labeled as BMP 101. 2. We are also proposing StormTech Isolator Rows (which will act as infiltration trenches) within the underground detention system. SECTION II: APPENDIX A. SITE INFORMATION B. EXISTING CONDITIONS D. STORMWATER QUALITY DATA