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HomeMy WebLinkAbout005 - Roers Building A and B - Storm ReportAPPENDIX A APPENDIX B RATIONAL METHOD FOR ANALYSIS OF STORM WATER RETENTION Roers Apts | Subbasin 1, Basin P-1 - 10 Year Design Storm Frequency Design Storm Frequency = Year Input values for runoff coefficients from appropriate tables. 1Weighted runoff coefficient, Cwd = SCjAj / Saj where Cj is the adjusted runoff coefficient for surface type j and Aj is the area of surface type j Calculation of Storm Water Runoff Flow Rate: Q = Storm Water Runoff Flow Rate (cfs) i = Rainfall Intensity (in/hr) Cwd = Weighted Runoff Coefficient A = Storm Drainage Basin Area (acres) Storm Drainage Basin Weighted Runoff Coefficient, Cwd = Rainfall Intensity, i =in/hr (10-year, 2-hour Design Storm) Storm Drainage Basin Area, A =acres Basin Design Peak Flow, Qp =cfs Calculation of Required Retention Volume: Q = Storm Water Runoff Flow Rate (cfs) V = Required Retention Volume (cf) Storm Drainage Basin Runoff Flow Rate, Q =cfs Basin Required Retention Volume, V = cf 10 (Enter WQual, 2, 5, 10, 25, 50, or 100) DRAINAGE BASIN CHARACTERISTICS Weighted Adjusted Runoff Surface Area, A Area, A Coefficient Coefficient1 Factor C' = Cwd x Cf Runoff Runoff Frequency Coefficient Description (ft2)(acres) C C x A Cwd Cf Cwd x Cf → Cwd x Cf ≤ 1.00 C' x A Hard Surface (back, sides parking) 73,250 1.682 0.95 1.598 0.87 1.00 0.87 1.616 Landscape 7,978 0.183 0.10 0.018 0.87 Totals 81,228 1.865 1.616 0.66 4,744.98 1.616 BASIN RETENTION VOLUME ANALYSIS 0.87 0.41 1.865 0.66 = =7200 1 RATIONAL METHOD FOR ANALYSIS OF STORM WATER RETENTION Roers Apts | Subbasin 2, Basin P-2 - 10 Year Design Storm Frequency Design Storm Frequency = Year Input values for runoff coefficients from appropriate tables. 1Weighted runoff coefficient, Cwd = SCjAj / Saj where Cj is the adjusted runoff coefficient for surface type j and Aj is the area of surface type j Calculation of Storm Water Runoff Flow Rate: Q = Storm Water Runoff Flow Rate (cfs) i = Rainfall Intensity (in/hr) Cwd = Weighted Runoff Coefficient A = Storm Drainage Basin Area (acres) Storm Drainage Basin Weighted Runoff Coefficient, Cwd = Rainfall Intensity, i =in/hr (10-year, 2-hour Design Storm) Storm Drainage Basin Area, A =acres Basin Design Peak Flow, Qp =cfs Calculation of Required Retention Volume: Q = Storm Water Runoff Flow Rate (cfs) V = Required Retention Volume (cf) Storm Drainage Basin Runoff Flow Rate, Q =cfs Basin Required Retention Volume, V = cf 10 (Enter WQual, 2, 5, 10, 25, 50, or 100) DRAINAGE BASIN CHARACTERISTICS Weighted Adjusted Runoff Runoff Runoff Frequency Coefficient Surface Area, A Area, A Coefficient Coefficient1 Factor C' = Cwd x Cf Description (ft2)(acres) C C x A Cwd Cf Cwd x Cf → Cwd x Cf ≤ 1.00 C' x A Hard Surface (back, sides parking) 23,247 0.534 0.95 0.507 0.74 1.00 0.74 0.524 Landscaping 7,498 0.172 0.10 0.017 Undeveloped 0.20 0.74 Totals 30,745 0.706 0.524 0.21 1,539.39 0.524 BASIN RETENTION VOLUME ANALYSIS 0.74 0.41 0.706 0.21 = = 7200 1 RATIONAL METHOD FOR ANALYSIS OF STORM WATER RETENTION Roers Apts | Subbasin 3, Basin A (offsite) - 10 Year Design Storm Frequency Design Storm Frequency = Year Input values for runoff coefficients from appropriate tables. 1Weighted runoff coefficient, Cwd = SCjAj / Saj where Cj is the adjusted runoff coefficient for surface type j and Aj is the area of surface type j Calculation of Storm Water Runoff Flow Rate: Q = Storm Water Runoff Flow Rate (cfs) i = Rainfall Intensity (in/hr) Cwd = Weighted Runoff Coefficient A = Storm Drainage Basin Area (acres) Storm Drainage Basin Weighted Runoff Coefficient, Cwd = Rainfall Intensity, i =in/hr (10-year, 2-hour Design Storm) Storm Drainage Basin Area, A =acres Basin Design Peak Flow, Qp =cfs Calculation of Required Retention Volume: Q = Storm Water Runoff Flow Rate (cfs)0,0 V = Required Retention Volume (cf) Storm Drainage Basin Runoff Flow Rate, Q =cfs Basin Required Retention Volume, V = cf 10 (Enter WQual, 2, 5, 10, 25, 50, or 100) DRAINAGE BASIN CHARACTERISTICS Weighted Adjusted Runoff Surface Area, A Area, A Coefficient Coefficient1 Factor C' = Cwd x Cf Runoff Runoff Frequency Coefficient Description (ft2)(acres) C C x A Cwd Cf Cwd x Cf → Cwd x Cf ≤ 1.00 C' x A Hard Surface (back, sides parking) 136,473 3.133 0.95 2.976 0.74 1.00 0.74 3.080 Landscaping 45,201 1.038 0.10 0.104 Undeveloped 0 0.000 0.20 0.000 0.74 Totals 181,674 4.171 3.080 1.26 9,045.01 3.080 BASIN RETENTION VOLUME ANALYSIS 0.74 0.41 4.171 1.26 = = 7200 1 RATIONAL METHOD FOR ANALYSIS OF STORM WATER RETENTION Roers Apts | Subbasin 4, Drywell - 10 Year Design Storm Frequency Design Storm Frequency = Year Input values for runoff coefficients from appropriate tables. 1Weighted runoff coefficient, Cwd = SCjAj / Saj where Cj is the adjusted runoff coefficient for surface type j and Aj is the area of surface type j Calculation of Storm Water Runoff Flow Rate: Q = Storm Water Runoff Flow Rate (cfs) i = Rainfall Intensity (in/hr) Cwd = Weighted Runoff Coefficient A = Storm Drainage Basin Area (acres) Storm Drainage Basin Weighted Runoff Coefficient, Cwd = Rainfall Intensity, i =in/hr (10-year, 2-hour Design Storm) Storm Drainage Basin Area, A =acres Basin Design Peak Flow, Qp =cfs Calculation of Required Retention Volume: Q = Storm Water Runoff Flow Rate (cfs)0,0 V = Required Retention Volume (cf) Storm Drainage Basin Runoff Flow Rate, Q =cfs Basin Required Retention Volume, V = cf 10 (Enter WQual, 2, 5, 10, 25, 50, or 100) DRAINAGE BASIN CHARACTERISTICS Weighted Adjusted Runoff Runoff Runoff Frequency Coefficient Surface Area, A Area, A Coefficient Coefficient1 Factor C' = Cwd x Cf Description (ft2)(acres) C C x A Cwd Cf Cwd x Cf → Cwd x Cf ≤ 1.00 C' x A Hard Surface (back, sides parking) 0 0.000 0.95 0.000 0.10 1.000.000 0.20 0.000 0.10 Landscaping 2,922 0.067 0.10 0.007 Undeveloped 0 0.007 BASIN RETENTION VOLUME ANALYSIS 0.10 0.41 0.067 0.00 Totals 2,922 0.067 0.007 0.10 0.007 0.00 19.70 = = 7200 1 APPENDIX C Roers Bozeman Apartments Pipe Calculations (25-yr storm) MODIFIED RATIONAL METHOD Qp = C i A Qp = 25-yr peak runoff, cfs C = runoff coefficient i = 0.78(Tc/60)-0.64 (Bozeman IDF curve) Tc = time of concentration, minutes A = Area, acres Conveyance Pipe (App A) Contributing Sub-basins Area1 C Tc Qpipe2 (cfs)Pipe Dia. & Slope Pipe Capacity3 (cfs) BASIN 1 P1 1.1 0.19 0.87 5.00 0.63 8" @ 0.6% slope 0.85 P2 1.2 0.57 0.87 5.00 1.90 12" @ 1.0% slope 3.25 P3 1.3 0.31 0.87 5.00 1.03 8" @ 1.1% slope 1.17 C1 1.4 0.26 0.87 5.00 0.87 1' WIDE @ 0.8%1.4 *CURB CUT C2 1.5 0.29 0.87 5.00 0.97 1' WIDE @ 0.8%1.4 *CURB CUT C3 1.6 0.11 0.87 5.00 0.37 1' WIDE @ 0.8%1.4 *CURB CUT P4 1.2, 1.3 0.76 0.87 5.00 2.53 12" @ 1.0% slope 3.25 BASIN 2 P5 2.1 0.59 0.74 5.00 1.67 12" @ 0.5%2.3 C4 2.2 0.12 0.74 5.00 0.34 1' WIDE @ 0.8%1.4 *CURBCUT BASIN 3 P6 3.01 0.66 0.74 5.00 1.87 12" @ 1.0% slope 3.25 P7 3.02 0.62 0.74 5.00 1.76 8" @ 7.3% slope 3.01 P8 3.03 0.33 0.74 5.00 0.93 8" @ 1% slope 1.11 P9 3.04 0.15 0.74 5.00 0.42 6" @ 2% slope 0.74 - 3.05 0.78 0.74 5.00 2.21 -- P10 3.03, 3.04 0.48 0.74 5.00 1.36 12" @ 0.70% slope 2.72 P11 3.03, 3.04, 3.05 1.26 0.74 5.00 3.57 15" @ 0.94% slope 5.73 P12 3.02, 3.03, 3.04, 3.05 1.88 0.74 5.00 5.32 15" @ 1.0% slope 5.91 P13 3.06 0.25 0.74 5.00 0.71 8" @ 2.0% slope 1.57 P14 3.07 0.25 0.74 5.00 0.71 8" @ 0.8% slope 1.00 - 3.08 0.38 0.74 5.00 1.08 -- P15 3.07, 3.08 0.63 0.74 5.00 1.78 12" @ 0.5% slope 2.3 - 3.09 0.12 0.74 5.00 0.34 -- P16 3.07, 3.08, 3.09 0.75 0.74 5.00 2.12 12" @ 0.5% slope 2.3 - 3.10 0.13 0.74 5.00 0.37 -- P17 3.06, 3.07, 3.08, 3.09, 3.10 1.13 0.74 5.00 3.20 15" @ 0.3% slope 3.54 FOOTNOTES: 1. Contributing drainage area (conservatively high in some cases) 2. Qpipe is the total 25-year peak runoff (direct surface runoff plus flows from upstream pipes) to the pipe draining the indicated structure/flow entry point. 3 Capactiy is determined using Hydraflow Express to calculate maximum flow through the pipe at the specified diameter and slope at 75% d/D. APPENDIX D Engineering Design Report Urban + Farm Phase 2 Infrastructure Improvements Bozeman Gallatin County, Montana November 20, 2023 Prepared For: Laurel Parkway LLC & Baxter Creek LLC 11 Lone Peak Dr Big Sky, Montana 59716 Prepared By: Hyalite Engineers, PLLC 2304 N 7th Ave. Suite L Bozeman, MT 59715 Engineering Report – Urban + Farm Phase 2 Table of Contents November 2023 Page ii Version 11/21/2023 Table of Contents Table of Contents ........................................................................................................................ ii 1 Introduction ......................................................................................................................... 3 1.1 Purpose of Report ........................................................................................................ 3 1.2 Scope .......................................................................................................................... 3 2 Location and Site Information ............................................................................................. 3 3 Land Use ............................................................................................................................ 4 3.1 Existing ........................................................................................................................ 4 3.2 Proposed ..................................................................................................................... 4 4 Water System ..................................................................................................................... 4 4.1 Water Use Data ........................................................................................................... 4 4.2 Fire Flow ...................................................................................................................... 5 5 Sewer System ..................................................................................................................... 6 5.1 Design Flow Rates ....................................................................................................... 6 6 Stormwater Network ........................................................................................................... 7 6.1 General Design ............................................................................................................ 8 6.2 Hydrologic Methodology............................................................................................... 8 6.3 Basin A Detention Pond ..............................................................................................10 6.4 Basin B Retention Pond ..............................................................................................11 6.5 Basin C Detention Chambers ......................................................................................11 6.6 Basin D Detention Pond ..............................................................................................11 6.7 Retention Pond E ........................................................................................................12 6.8 Retention Pond F ........................................................................................................12 6.9 Inlets & Storm Sewer ..................................................................................................12 6.10 Groundwater ...............................................................................................................13 6.11 System Maintenance ..................................................................................................13 6.12 Erosion Sediment Control ...........................................................................................14 6.13 Flooding ......................................................................................................................14 Engineering Report – Urban + Farm Phase 2 Introduction November 2023 Page 3 Version 11/21/2023 1 Introduction 1.1 Purpose of Report This report is intended to serve as the design document for the infrastructure improvements associated with the construction of a 33-lot major subdivision. The proposed infrastructure has been designed accounting for future connections, as the property is bordered to the south and west by undeveloped land. 1.2 Scope Expansion of existing infrastructure (roads, water and sewer mains) and storm water design elements are within the scope of this report. All improvements analyzed in this report are within the property with proposed connections to existing infrastructure. No off-site improvements are expected. 2 Location and Site Information The property occupies 86.45 acres and is located on the western side of Bozeman and is bordered to the north by Norton East Ranch Phase 4 and J C Billion Auto Plaza Subdivision to the East, in the S ½ of Section 9, Township 2 South, Range 5 East, P.M.M., City of Bozeman, Gallatin County, MT. The existing zoning is REMU and B-2M. The nearby surrounding zoning is R-4, R-5, RO, and B-2. The property is within the service area for municipal water and sewer from the City of Bozeman. Figure 1 - Vicinity map. Engineering Report – Urban + Farm Phase 2 Land Use November 2023 Page 4 Version 11/21/2023 3 Land Use 3.1 Existing The site is currently two vacant lots with six existing intersection tie-ins –South Eldorado Avenue, South Reliance Avenue, South Laurel Parkway, Pond Lily Drive, Water Lily Drive, and Competition Drive. The majority of the site has been left undisturbed. The subject area is comprised of 82.14 acres of B-2M zoning and 4.31 acres of REMU zoning. 3.2 Proposed The proposed major subdivision will consist of 33 developable lots & is proposed to satisfy section 38.410.130 by cash-in-lieu water rights payments, as well as existing irrigation wells. At this time, those cash-in-lieu of water rights fees will be deferred until future site plan or subdivision application. The lots will be comprised of commercial and residential uses. Through this development South Eldorado Avenue, South Reliance Avenue, South Laurel Parkway, Pond Lily Drive, Water Lily Drive, and Competition Drive will all be extended. Both water and sewer mains will connect to existing stub-outs from the improvements associated with surrounding developments. Water and sewer mains will provide service to the proposed lots through main extensions and service connections. Stormwater storage ponds will be sized to accommodate the runoff rates and volumes from this project, see section 6 of this report. 4 Water System The proposed water system will connect to and extend existing mains installed during the development of the East Norton Ranch Phase 4, Urban + Farm Phase 1, and to the west in Competition drive. The water system will be looped into the City of Bozeman water system at South Eldorado, South Reliance, South Laurel Parkway, Pond Lily Drive, Water Lily Drive, and Competition Drive. New water mains will be 8”, 12”, or 16” diameter, class 51 ductile iron pipe. Part of the proposed development will include the connection to the existing network south of Huffine Lane. As part of this connection a PRV will be installed on the south side of Huffine Lane. This PRV will be connected to the existing 10” main and will reduce the pressure coming from the south zone to the west zone. New 16” ductile iron pipe water main will be provided to the proposed connection point at Laurel Parkway. The 12” main in Laurel Parkway will be installed in a new casing bored under Huffine Lane to connect to the new 16” main along the south side of Huffine Lane. Fire hydrant leads will be 6” diameter ductile iron pipe as well. All mains will be wrapped in V-Bio Enhanced Polyethylene Encasement per DIRPA recommendations. Lots will be provided connection to city water by either a 2” type K copper water service and a 4” class 51 ductile iron pipe for fire service, or an 8” water main extended into the lot and capped for future main extensions and services. 4.1 Water Use Data Average Daily Flow Average day use B-2M = 705 gpd/ac Average day use REMU = 873 gpd/ac Engineering Report – Urban + Farm Phase 2 Water System November 2023 Page 5 Version 11/21/2023 Acres B-2M = 82.14 Ac Acres REMU = 4.31 Ac 82.14 ac at 705 gpd/ac = 57,908.7 gpd 4.31 ac at 873 gpd/ac = 3,762.6 gpd Total Average Daily Flow = 61,671.3 GPD Peak Demand Peaking factor = 2.3 (peaking factor per City of Bozeman Design Standards) 61,671.3 gpd (2.3) = 141,843.99 gpd Total max day flow = 141,843.99 gpd / 1440 min/day = 98.50 GPM instantaneously Peak Hour Demand 61,671.3 gpd (3) = 185,013.9 gpd = 128.48 GPM 4.2 Fire Flow Required fire flow for B-2M and REMU zonings is 3,000 gpm. With a Peak Hour Demand of 128.48 gpm and a fire requirement of 3,000 gpm total flow requirement is 3,128.48 gpm. Fire hydrant data has been provided for surrounding hydrants demonstrating adequate fire flow for the development. Nearby hydrant #2673 has an available flow of 5,117 gpm at a residual pressure of 20 psi. The proposed development will be entirely in the West Pressure Zone. This pressure zone is a sub-zone within the South zone. The West Zone has an operating hydraulic grade line of 4,980. In order to model fire flow availability a WaterCAD model was built using reservoirs to supply water as well as pressure to the system. The proposed development will be supplied water from three major connection points, a 12” main in West Babcock, an 8” main in Fallon, and a new tie in location from Loyal gardens which will cross Huffine. The connections in West Babcock and Fallon are part of the existing network of the Norton Ranch developments and supply water to the entire area. In order to properly model these connections much of the existing network was included in the WaterCAD model. Using the operating HGL of 4,890 three reservoirs were placed at the three connection points. These reservoirs are the sole source of water as well as pressure for the model. System peak hour demands from the proposed development were distributed throughout the network. Required fire flow for the development is 3,000 gpm at 20 psi based on zoning. A fire flow analysis scenario was ran on the system to determine if adequate fire suppression flow rates are available. All hydrants in the system provide a minimum of 3,000 gpm at 20 psi. The City of Bozeman has provided hydrant data for hydrant #2673. As a check on the model this existing hydrant was also included as part of the network. In order to compare the hydrant, the model was ran with only the existing tie-in locations supplying water and pressure. This scenario models the existing system without the third proposed tie-in. When running the existing scenario, the predicted fire flow available from hydrant #2673 at 20 psi is 5,254 gpm. The provided data from the City of Bozeman claims hydrant #2673 can supply 5,117 gpm at 20 psi. This analysis check demonstrates that the model built for Urban + Farm Phase 2 is comparable to the model being used by the City of Bozeman. Engineering Report – Urban + Farm Phase 2 Sewer System November 2023 Page 6 Version 11/21/2023 5 Sewer System The proposed development will extend existing sewer mains throughout the development to supply wastewater service to the proposed lots through either sewer services or main extension. Each lot will have wither a 6” sewer service or an 8” sewer main stubbed into the property and capped. The proposed development will be comprised of two sewer drainage basins. The west portion of the development will flow north into the existing 10” sewer main that was created during the construction of Phase 4 of Norton East Ranch. This existing 10” sewer main ultimately conveys wastewater to the Norton Ranch Lift Station. The Norton Ranch Lift Station is currently at capacity and requires upgrades. A long-term improvement plan is currently being created for the upgrade required for the lift station. Hyalite has been working with surrounding developers as well as HDR for the required upgrades and cost share. An analysis of capacity the existing sewer network has been conducted in previous analysis demonstrating adequate pipe sizing in existing infrastructure. The eastern portion of the proposed development will generally flow north east where the proposed sewer main network will connect to an existing manhole in Competition Drive. From this existing manhole wastewater will flow east down Fallon Street in an 8” main and will ultimately flow into South Cottonwood Road. According to the City of Bozeman the sewer mains that the east portion of the proposed development will contribute to are less than 50% obligated. 5.1 Design Flow Rates Average Daily Flow West Basin Average day use B-2M = 2,000 gpd/ac Average day use REMU = 1,456 gpd/ac Acres B-2M = 47.45 Ac Acres REMU = 4.31 Ac 47.45 ac at 2,000 gpd/ac = 94,900 gpd 4.31 ac at 1,456 gpd/ac = 6,275.36 gpd Total Average Daily Flow = 101,175 GPD Peak Flow West Basin Assuming 2000 gallons per acre and 89 gallons per capita = (2000 gal/ac) / (89 gal/capita) = 22.47 persons/acre (51.76 ac) x (22.47 persons/ac) = 1,163 persons Peaking Factor = (18+1.1631/2) / (4+1.1631/2) = 3.62 Peak Hour Flow = 3.62 x 101,175 gpd = 366,254 gpd Peak Hour Flow = 254.34 gpm. Including infiltration: 150 gallons/acre/day (51.76 acres) = 7,764 gpd = 5.39 gpm Peak hour flow (including infiltration) = 259.68 GPM Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 7 Version 11/21/2023 Average Daily Flow East Basin Average day use B-2M = 2,000 gpd/ac Acres B-2M = 34.67 Ac 34.67 ac at 2,000 gpd/ac = 69,340 GPD Peak Flow East Basin Assuming 22.47 persons/acre (34.67 ac) x (22.47 persons/ac) = 779 persons Peaking Factor = (18+0.7791/2) / (4+0.7791/2) = 3.87 Peak Hour Flow = 3.87 x 69,340 gpd = 268,346 gpd Peak Hour Flow = 186.35 gpm Including Infiltration: 150 gallons/acre/day (34.67 acres) = 5,201 = 3.61 gpm Peak Hour Flow (including infiltration) = 189.96 GPM The proposed 8” gravity main in the west basin are capable of flowing 259.68 gpm at minimum slope (0.40%) with a depth of 5.2 inches. The proposed 10” gravity main in the west basin is capable of flowing 259.68 gpm at minimum slope (0.28%) with a depth of 5 inches. A Manning’s friction factor of 0.013 was used to calculate normal depth. The existing sewer network that will be affected by the proposed development has been analyzed for capacity. The existing 10” sewer main in Reliance as well as the existing 15” sewer main in Laurel Parkway are adequately sized for the proposed development. The analysis was conducted during the design and permitting of Urban + Farm Phase 1 and was performed using more conservative methods than what is used in this report. The proposed 8” gravity sewer mains in the east basin are capable of flowing 189.96 gpm at minimum slope (0.40%) with a depth of 4.8 inches. A Manning’s friction factor of 0.013 was used to calculate normal depth. 6 Stormwater Network This section provides a design basis and hydraulic calculations for sizing storm water facilities for Urban + Farm Phase 2. The City of Bozeman Design Standards were used as the primary guidelines for this stormwater drainage design. Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 8 Version 11/21/2023 6.1 General Design The proposed development will be a combination of roadway, residential, and commercial lots as well as parks and open space. The proposed streets will be paved with curb and gutter. Stormwater runoff generated from the roadway and lots is designed to be collected by the curb and gutter and then directed toward storm drain inlets. The runoff will then either infiltrate or move through storm sewer system pipes to detention/retention ponds associated with each basin. The entire area within the proposed development was accounted for in the design of the stormwater infrastructure, including the lot areas outside of the publicly dedicated rights-of-way. The proposed stormwater piping, ponds, inlets, etc. have been sized appropriately for the entire development based on current zoning/anticipated land use (see included Storm Water Basins figure 1 of 2 and the corresponding Runoff Coefficient in Section 6.2 in this report), and analyzed in each of the stormwater basins described below. This methodology is practical for the majority of the development, however, due to existing topography, some lots/areas will have difficulty routing all stormwater to the common infrastructure and thus a portion of the stormwater runoff may need to be mitigated on-site. Future development on each of the lots created with Urban + Farm Phase 2 will be subject to stormwater design review through the City of Bozeman’s Site Plan review process. 6.2 Hydrologic Methodology The rational method was used to determine peak runoff rates. The rational formula provides a peak runoff rate which occurs at the time of concentration. Q = CiA Where C = Weighted C Factor i= Storm Intensity (in/hr) A = Area (acres) Q = Runoff (cfs) The storm intensities were developed from the IDF curve found in Figure I-2 of the City of Bozeman Design Standards and Specifications. Runoff coefficients for each basin were calculated using a weighted percentile of impervious and pervious area. The coefficient used are shown in the table below. Table 1 - Runoff coefficients used. RUNOFF COEFFICIENTS Open Land 0.2 Dense Residential 0.5 Commercial 0.60 R.O.W. 0.73 The right-of-way coefficient was determined using quantities from the local street cross section detail (see sheet C5.16). Of the 60-foot right-of-way, 45-feet is impervious and the remaining 15- Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 9 Version 11/21/2023 feet is considered open land. Using those quantities and their corresponding C-values provides a cumulative C-value of 0.73. Time of concentration of overland flow was determined using the following equation: Tc = 1.87(1.1-C)D1/2 S1/3 Where Tc = Time of Concentration, minutes S= Slope of Basin, % C= Runoff Coefficient D= Length of Basin, ft Time of concentration for gutter flow was determined using the following equation for shallow concentrated flow velocity: V = KukS0.5 Tc = D/(60V) Where V = velocity, fps Ku = unit conversion, 3.28 k = intercept coefficient S = slope, % Tc = Time of Concentration, minutes D= Length of Basin, ft V= Velocity, fps The rational method was used to compute runoff flow rates. This method can be used for storm durations equal or greater than the time of concentration. This method assumes the maximum runoff rate occurs at the time of concentration and continues to the end of the storm. Maximum runoff rates for durations greater than the time of concentration are less than the peak runoff rate because average storm intensities decrease as duration increases. Retention volumes were calculated using the modified rational method. The modified rational method uses peak flow rates to determine volume. The peak flow rate is determined using the rational method, that peak flow rate is conservatively held constant for the duration of the storm. The volume of retention volume required is calculated by multiplying the peak runoff by storm duration. City of Bozeman Standards requires that retention volumes be calculated for a 10-yr 2-hr design storm. The intensities are developed from the IDF curve found in Figure I-2 of the City of Bozeman Design Standards and Specifications. Runoff coefficients are taken from Table 1. Retention volume is determined using the following equation: V = 7200Q Where V = Volume, cf Q = flow rate, cfs The City of Bozeman requires infiltration, evapotranspiration or capture for reuse of the runoff generated from the first 0.5 inches of rainfall from a 24-hour storm. A common methodology for estimating the volume of direct runoff from a drainage basin is the SCS method. This method requires basic data similar to the Rational Method: drainage area, a runoff factor, time of concentration, and rainfall. However, the SCS approach is more sophisticated in that it also Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 10 Version 11/21/2023 considers the time distribution of the rainfall and an infiltration rate that decreases during the course of a storm. The SCS method takes into account the Initial Abstraction (Ia) which is all losses before runoff begins. This includes surface depressions, water intercepted by vegetation, evapotranspiration and infiltration. Initial abstraction generally correlates with soil and cover parameters. Through studies of many small watersheds, Ia was found to be approximated by the following empirical equation: Ia = 0.2 x S [eq. 2-2 TR-55] Where S = (1000/CN) – 10 [eq. 2-4 TR-55] According to USDA’s Urban Hydrology for Small Watersheds, the Curve Number associated with soil type B and 1/8 acre residential lots is 85 (Table 2-2a). 1/8 acre lots was selected based on a high residential density. Using the standard SCS method, S = (1000/85) – 10 = 1.8 inches Ia = 0.2 * 1.8 inches = 0.4 inches 6.3 Basin A Detention Chambers Detention Pond A is designed to discharge stormwater runoff at a rate less than the predevelopment rate from the 10-year storm. This runoff rate was determined using the rational method per City of Bozeman Design Standards and was determined based on the remaining capacity in the Norton Ranch Phase 5 detention pond. The release rate will be controlled by an outlet weir which has been designed to reduce discharge to the predetermined rates for remaining capacity of the Norton Ranch Phase 5 detention pond and allow the 100-year event to overtop the weir and discharge at an unrestricted release rate. The detention pond will discharge into existing storm infrastructure that was installed & approved as part of Urban + Farm Phase 1. The 2.5 cfs release rate from Pond A was accounted for in the Urban + Farm Phase 1 storm pipe calculations, and the downstream infrastructure from Pond A’s outlet was analyzed in Section 6.4 of the Urban + Farm Phase 1 Engineering Report. The additional capacity of the existing 15” stormwater pipe (Norton Ranch Phase 3C) was calculated to be 7.61 cfs, with the flowrate from Urban + Farm Phase 1 being 4.68 cfs. The addition of the 2.50 cfs outlet from the proposed Pond A results in 7.18 cfs total. This existing infrastructure connects to the Norton Ranch stormwater network which ultimately discharges to a detention pond created with Phase 5 of Norton Ranch. The Phase 5 Norton Ranch Detention pond then discharges stormwater to Aajker Creek at a pre-development rate per separate approvals. Basin A was not originally planned as a contributing area to the Norton Ranch Phase 5 detention pond; however, the Norton Ranch Phase 5 detention pond was oversized leaving an additional storage volume of 10,649 cubic feet. This oversizing was originally for the potential groundwater infiltration that occurs in the area, but after subsequent fixes made by Norton Ranch, the then available capacity was able to be utilized for additional detention capacity. The Norton Ranch Phase 5 detention pond has been analyzed with the additional contributing area and is currently adequately sized. Detention Pond A is required to have a volume of 34,856 cubic feet. Using a 10-year 24-hour rain event in the City of Bozeman, the total precipitation (P) is 1.88 inches of which 0.4 inches is lost due to initial abstraction according to USDA’s SCS method. Therefore, Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 11 Version 11/21/2023 this drainage plan includes provision for the first 0.4 inches of rainfall from the 24-hour storm to be retained in surface depressions, intercepted by vegetation, or evapotranspired or infiltrated. The remaining 0.1 inches required to be captured is accounted for by setting the weir elevation above the bottom of the pond to retain the volume from the remaining 0.1 inches. The remaining volume from the first 0.5” is 18,769 cubic feet. The detention pond will utilize three separate, stepped, perforated underground storage sections, each being hydraulically connected and consisting of identical chamber layouts. The invert elevation of each of the chamber sections steps in elevation to maintain separation from seasonally high groundwater. Each of the chamber sections will be outlet controlled to ensure that the entire volume of each section will be used, with the furthest downstream outlet being held to 2.5 cfs. 6.4 Basin B Retention Chambers Basin B is centrally located on the subject property. Stormwater runoff from Basin B will be conveyed to a retention pond located along the north border of the site. Stormwater will be conveyed through the use of storm drain inlets and piping. Basin B is comprised of right-of-way, high density residential, and opens space. This retention pond is sized to handle the entire volume of a 10-year, 2-hour storm event. This retention pond will store runoff as it evaporates and percolates into the existing gravels on site. The required retention storage for Basin B is 45,903 cubic feet. The detention pond will utilize three separate perforated underground storage sections, each being hydraulically connected and consisting of identical chamber layouts. The invert elevation of each of the chamber sections steps in elevation to maintain separation from seasonally high groundwater. Each of the two upstream chamber sections will be outlet controlled to ensure that the entire volume of each section will be used, and no outlet will be installed for the furthest downstream chamber section. 6.5 Basin C Detention Chambers Basin C has been split into two separate basins: C1 and C2. Basin C1 is the southern half of the basin, with C2 being the remaining northern portion. All southern infrastructure in Basin C will convey stormwater runoff to the underground storage facility C1 located near the center of Water Lily Drive. The stormwater will then discharge into the northern infrastructure and will ultimately be conveyed through Pond C2 and into Baxter Creek. Each of the Ponds C1 and C2 are sized for their respective basin areas and will be controlled by an outlet weir which has been designed to reduce discharge to the predevelopment runoff rates. Using a 10-year 24-hour rain event in the City of Bozeman the total precipitation (P) is 1.88 inches of which 0.4 inches is lost due to initial abstraction according to USDA’s SCS method. Therefore, this drainage plan includes provision for the first 0.4 inches of rainfall from the 24-hour storm to be retained in surface depressions, intercepted by vegetation, or evapotranspired or infiltrated. The remaining 0.1 inches required to be captured is accounted for by setting the weir elevation above the bottom of the chambers to retain the volume from the remaining 0.1 inches. The remaining volume from the first 0.5” is 11,864 cubic feet. 6.6 Basin D Detention Pond Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 12 Version 11/21/2023 Detention Pond D is designed to discharge stormwater runoff at the predevelopment rate from the 10-year storm. This runoff rate was determined using the rational method per City of Bozeman Design Standard. The release rate will be controlled by an outlet weir which has been designed to reduce discharge to the predevelopment rates and allow the 100-year event to overtop the weir and discharge at an unrestricted release rate. The detention pond will discharge into Baxter Creek at the predevelopment rate. With the proposed development the required storage volume for the Basin D detention pond is 1,788 cubic feet. Using a 10-year 24-hour rain event in the City of Bozeman the total precipitation (P) is 1.88 inches of which 0.4 inches is lost due to initial abstraction according to USDA’s SCS method. Therefore, this drainage plan includes provision for the first 0.4 inches of rainfall from the 24-hour storm to be retained in surface depressions, intercepted by vegetation, or evapotranspired or infiltrated. The remaining 0.1 inches required to be captured is accounted for by setting the weir elevation above the bottom of the pond to retain the volume from the remaining 0.1 inches. The remaining volume from the first 0.5” is 1,258 cubic feet. The detention pond was sized using City of Bozeman Design Standards, and side slopes will be no steeper than 4:1. 6.7 Retention Pond E Retention Pond E is located within sub-basin 16B. Stormwater runoff from sub-basin 16B will be conveyed to the retention pond located along the north border of the sub-basin area. Stormwater will be conveyed over a flow over forebay manhole, into rip rap which leads into the proposed pond. Sub-basin 16B is comprised of right-of-way, high density residential, and opens space. This retention pond is sized to handle the entire volume of a 10-year, 2-hour storm event. This retention pond will store runoff as it evaporates and percolates into the existing gravels on site. The required retention storage for Pond E is 1,082 cubic feet. The retention pond was sized using City of Bozeman Design Standards, and side slopes will be no steeper than 4:1. 6.8 Retention Pond F Retention Pond F is located within sub-basin 17B. Stormwater runoff from sub-basin 17B will be conveyed to the retention pond located along the north border of the sub-basin area. Stormwater will be conveyed over a flow over forebay manhole, into rip rap which leads into the proposed pond. Sub-basin 17B is comprised of right-of-way and high density residential area. This retention pond is sized to handle the entire volume of a 10-year, 2-hour storm event. This retention pond will store runoff as it evaporates and percolates into the existing gravels on site. The required retention storage for Pond F is 292 cubic feet. The retention pond was sized using City of Bozeman Design Standards, and side slopes will be no steeper than 4:1. 6.9 Off-site Sub-basins Three street drainage sub-basins discharge directly off-site. The three sub-basins consist of the northernmost portions of Eldorado Avenue, Reliance Avenue, and Laurel Parkway rights of way, totaling 38,339 square feet in area. Per the City of Bozeman Design Standards, adequate on-site Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 13 Version 11/21/2023 stormwater detention shall be provided for design storm runoff exceeding the pre-development rate. As the contributing runoff for each of these sub-basins is much less than the pre-developed rate of the basin as a whole, on-site detention is not provided. Each of these sub-basins will runoff to the north and be captured within Urban + Farm Phase 1 infrastructure, and ultimately discharge in the Norton Ranch Phase 5 detention pond. With Basin A of the proposed development (described above), the required storage volume for the Norton Ranch Phase 5 detention pond is 47,185 cubic feet and the provided volume is 47,688 cubic feet. Of the 503 cubic feet of available storage, 319 cubic feet will account for these three street drainage basins, based on the above-mentioned first 0.1” of rainfall on these areas. 6.10 Inlets & Storm Sewer Sub-basins were first analyzed using the Rational Method to determine the contributing flow from each of the sub-basin areas. Next, the hydrologic and hydraulic analyses were modeled using AutoDesk Storm and Sanitary Analysis 2023. This program is a continuous rainfall simulation model that simultaneously models hydrologic storm events and routes runoff through multiple stormwater structures. The Bozeman IDF curve was imported into the model and used to determine catchment area flows, pipe conveyance calculations, and inlet capacity. User defined sub-basin information (area, runoff coefficient, time of concentration) are entered into the model to achieve a more accurate representation. Storm pipes are sized to convey the 25-year design storm event. Pipes are sloped to maintain a minimum velocity of 3 ft/s when flowing full to prevent sediment deposit. A manning’s N of 0.013 was used for all storm pipe conveyance calculations. Each inlet grate has been located and deisgned to accommodate the 25-year storm event without exceeding a depth of 0.15’ below the top of the curb. Inlets and manholes will have a 9” sump for sediment collection. 6.11 Groundwater Groundwater is known to be high in this area. A geotechnical report was done in April 2021 that included borings near and on the property. Test Pit 1 was dug on site and Test Pit 2 was just south of the site. Groundwater was found at 4.8’ in Test Pit 1 and at 5.1’ in Test Pit 2. Test Pit 1 had a monitoring well installed and ground water depth has been recorded. Test Pit 1 had a maximum groundwater height of 2.56’ below the surface on May 20th, 2021. Groundwater monitoring data has been included in this submittal. The hydraulic gradient across the site has been modeled using the highest recorded measurement at each of the monitoring wells. The modeled groundwater surface was used for design of all site infrastructure. Irregular groundwater behavior was observed starting in April of 2022 and reached a peak during May of 2022. During this time construction on a nearby development resulted in the accidental damaging of an existing drain tile. Due to the break in the existing drain tile groundwater irregularly rose on site due to the lack of subsurface drainage. Since this break, the drain tile has been repaired and is functioning as in its previous state. Due to this irregularity data from the peak 2021 season has been used to establish groundwater elevations. 6.12 Park G Recreation Pond Overflow Engineering Report – Urban + Farm Phase 2 Stormwater Network November 2023 Page 14 Version 11/21/2023 The recreation pond located within Park G will be completely lined and fed by the nearby irrigation well. As the pond is man-made and does not have a natural outfall, the pond will discharge into an underground infiltration system that has been sized to accommodate the semi-continuous flow from the irrigation well. Percolation tests have been performed on-site to determine the infiltration rate of the system and infiltration system details have been included within the Storm Detail sheets. 6.13 System Maintenance Regular maintenance of stormwater facilities is necessary for proper function of the drainage system. All stormwater maintenance located outside of the public right-of-way will be owned and maintained by the property owners association. Maintenance items include removing debris from inlet grates and culverts, cleaning and flushing pipes, cleaning manhole sumps, and establishing ground cover after construction. 6.14 Erosion Sediment Control During construction, stormwater pollutant controls will include silt fencing, straw wattles, rock check dams, and straw bales. Silt fence, straw waddles, or other perimeter protection will be installed on the down gradient edge of disturbed soil. Straw wattles, straw bales, or other erosion protection will be placed near existing and newly installed culverts. Temporary erosion control measures will be installed and continuously maintained for the duration of construction. This project will require acceptance of a Stormwater Pollution Prevention Plan (SWPPP) permit for stormwater discharge associated with construction activity prior to starting any construction. Protection during and immediately after construction will be controlled in accordance with this permit and the Montana Sediment and Erosion Control Manual. Permanent erosion control will consist of implementation of seeding disturbed areas and placing riprap at pond inlet/outlets. Any visible sediment must be removed from the stormwater system prior to completing construction. 6.15 Flooding Excessive runoff from a large storm event (significantly exceeding the design storm, i.e 100-year) will be routed such that it does not inundate buildings, drainfields or over top the roadway. The stormwater infrastructure including ditches, culverts, and detention pond outlet structures have been analyzed for the 100-year storm. 10 yr Existing ConditionsProposed ConditionsBasin Sizing CalculationsWeighted C Value (Pre-Dev) Weighted C Value (Pre-Dev) Infiltration*Only used for 100-year analysisArea Area Area AreaObserved Percolation Rate 7.50 min/in(ft2) (acres) (ft2) (acres)8.00 in/hr 0.73 0.00 0.00 0.73 324470 7.45 5.440.50 0.00 0.00 0.50 1018729 23.39 11.69 Design Percolation Rate 4.00 in/hr0.60 0.00 0.00 0.60 0 0.00 0.00 Infiltrative Area 16410ft20.20 1531570 35.16 7.03 0.20 188322 4.32 0.86 Design Infiltration Rate 1.519 cfs1531570 35.16 7.03 1531521 35.16 18.00Duration Duration Intensity Q Runoff Release Required0.200.51min hr in/hr cfs Volume Volume Storage 5 0.08 3.22 57.92 17376 749.3 16626Time To Concentration TcTime To Concentration Tc10 0.17 2.05 36.91 22146 1498.5 20648Tc Overland Flow (Up to 400ft) Tc Overland Flow (Up to 400ft)15 0.25 1.58 28.36 25523 2247.8 23275Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards) Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards)20 0.33 1.31 23.52 28227 2997.0 2523025 0.42 1.13 20.35 30519 3746.3 26773C = Weighted C Factor 0.20 C = Weighted C Factor 0.51 30 0.50 1.00 18.07 32530 4495.5 28035Cf = Frequency Factor1.00Cf = Frequency Factor1.00 60 1.00 0.64 11.52 41462 8991.0 32471D = Length 400.00ftD = Length 400.00ft90 1.50 0.49 8.85 47784 13486.5 34298 S = Slope % 2.61%S = Slope % 2.40%120 2.00 0.41 7.34 52846 17982.0 34864150 2.50 0.35 6.35 57139 22477.5 34661Tc = 24.45MinutesTc = 16.43Minutes180 3.00 0.31 5.64 60904 26973.0 33931210 3.50 0.28 5.10 64280 31468.5 32811Tc Shallow Concentrated Flow (After 400ft) Tc Shallow Concentrated Flow (After 400ft)240 4.00 0.26 4.68 67355 35964.0 31391V = KukSp0.5 (HEC 22 eqn 3-4) V = KukSp0.5 (HEC 22 eqn 3-4)270 4.50 0.24 4.33 70190 40459.5 29730300 5.00 0.22 4.05 72827 44955.0 27872Ku = Conversion Factor3.28English UnitsKu = Conversion Factor3.28English Units330 5.50 0.21 3.80 75297 49451 25847k = Intercept Coefiicient 0.21HEC 22 Table 3-3k = Intercept Coefiicient 0.21HEC 22 Table 3-3Runoff Treatment Volume (Initial 0.5")Sp = Slope %1.19%Sp = Slope %1.20%Ia = 0.4 in0.5" - Ia=0.1 inV = 0.76ft/sV = 0.77ft/s1531521.00ft2D = 1023.00ftD = 960.00ft12763ft3Tc =22.37MinutesTc =20.91Minutes34864ft3Total Tc (Overland and Shallow Concentrated) Total Tc (Overland and Shallow Concentrated)Outlet Structure Q = CLH3/2 (City of Bozeman Design Standards)Tc = 46.82 Minutes Tc = 37.34 MinutesQ = Discharge 2.50 cfsRunoff Rate (Intensity @ Tc) Runoff Rate (Intensity @ Tc)C = Weir Coefficient 3.33i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr) i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr)H = Head 1 ftx = storm duration (hrs.) 0.78hrs.x = storm duration (hrs.) 0.62hrs.i = 0.75in/hri = 0.87in/hrL = Weir Width 0.750 ftQ = CiAQ = 5.29cfsQ = CiAQ = 15.68cfsL = Weir Width9.00inches100-Year Storm Design Check:Storm Event (yr):2 10 25 100V100YR/2HR :82,251.92cf V100YR/24HR :186,756.55cf*Storm Coeff. A:0.36 0.64 0.78 1.01Pond Area:16,410.00sfPond Area:16,410.00sf*Storm Coeff. B: 0.60 0.65 0.64 0.67Infiltration Rate:4.00in/hr Infiltration Rate:4.00in/hrComposite C:0.51 0.51 0.51 0.51 Volume Infiltrated : 10,940.00 cf Volume Infiltrated : 131,280.00 cf2-Hr Storm Intensity (in/hr):0.24 0.41 0.50 0.63 Max Pond Storage: 35,013.00 cf Max Pond Storage: 35,013.00 cf24-Hr Storm Intensity (in/hr):0.05 0.08 0.10 0.12 Max Pond Capacity45,953.00cf Max Pond Capacity166,293.00cf2 Hr Post-Dev Qp (cfs):4.27 7.34 9.01 11.42 24 Hr Post-Dev Qp (cfs):0.96 1.46 1.84 2.16C*Area100 Year StormRunoff Rate (City of Bozeman):Area = Initial 0.5" Pond Volume Req. =Minimum Pond Size Required = Urban + Farm Phase 2Basin A Detention Pond VolumeDesign Storm Frequency =R.O.W.Dense ResidentialCW =Land UseTotalsCW =CommercialOpen LandTotalsLand UseC C*AreaR.O.W.Dense ResidentialCommercialOpen LandC 10yrBasin Area (ac):29.741,295,474.40 (sq ft)Post-Dev C (weighted):0.53Storm Duration (min)120.00Area Runoff (acres) Coefficient CalculationsR.O.W.8.35 0.73 6.10Dense Residential17.53 0.50 8.77Open Land3.86 0.20 0.77Totals29.74 15.63Cw =0.53Storm Event (yr):2-yr, 2-hr 10-yr, 2-hr 25-yr, 2-hr 100-yr, 2-hr 100-yr, 24-hr*Storm Coeff. A:0.36 0.64 0.78 1.01 1.01*Storm Coeff. B:0.60 0.65 0.64 0.67 0.67Composite C:0.53 0.53 0.53 0.53 0.53Storm Intensity (in/hr):0.24 0.41 0.50 0.63 0.12Post-Dev Qp (cfs):3.71 6.38 7.82 9.92 1.88V100YR/2HR :71,448.35cf V100YR/24HR :162,226.58cf10-Year, 2 Hour StormPond Area:21,534.00sfPond Area:21,534.00sfDuration Time:7,200.00sec Infiltration Rate:4.00in/hr Infiltration Rate:2.00in/hrV10YR/2HR :45,906cfVolume Infiltrated :14,356.00cf Volume Infiltrated :86,136.00cfMax Pond Storage: 46,158.00cf Max Pond Storage: 46,158.00cfMax Pond Capacity 60,514.00 cf Max Pond Capacity 132,294.00 cfCN= 85S= 1.8 inIa = 0.4 in0.5" - Ia=0.1 inV1/2":15,876 cf*Values are from COB Design Standards Figure 2 - Rainfall Intensity Duration in MinutesUrban + Farm Phase 2Retention Pond BDesign Storm Frequency =Runoff Rate (Rational Method):100 Year Storm (Includes Infiltration)Runoff Treatment Volume (Initial 0.5"):Design Storm: 10-Year, 2-Hour (City of Bozeman)Weighted Runoff Co-efficent:Pond Size: 10 yr Existing ConditionsProposed ConditionsBasin Sizing CalculationsWeighted C Value (Pre-Dev) Weighted C Value (Pre-Dev) Infiltration*Only used for 100-year analysisArea Area Area AreaObserved Percolation Rate 7.50 min/in(ft2) (acres) (ft2) (acres)8.00 in/hr 0.73 0.00 0.00 0.73 139933 3.21 2.350.50 0.00 0.00 0.50 208470 4.79 2.39 Design Percolation Rate 4.00 in/hr 0.60 0.00 0.00 0.60 110699 2.54 1.52 Infiltrative Area 6300ft20.20 515315 11.83 2.37 0.20 56418 1.30 0.26 Design Infiltration Rate 0.583 cfs 515315 11.83 2.37 515520 11.83 6.52Duration Duration Intensity Q Runoff Release Required0.200.55min hr in/hr cfs Volume Volume Storage 2 0.03 5.84 38.08 4569 252.6 4317Time To Concentration TcTime To Concentration Tc4 0.07 3.72 24.27 5824 505.3 5319Tc Overland Flow (Up to 400ft) Tc Overland Flow (Up to 400ft)6 0.10 2.86 18.64 6712 757.9 5954Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards) Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards)8 0.13 2.37 15.46 7423 1010.6 641210 0.17 2.05 13.38 8026 1263.2 6763C = Weighted C Factor 0.20 C = Weighted C Factor 0.55 15 0.25 1.58 10.28 9250 1894.8 7355Cf = Frequency Factor1.00Cf = Frequency Factor1.00 20 0.33 1.31 8.52 10230 2526.5 7703D = Length 400.00ftD = Length 400.00ft25 0.42 1.13 7.37 11061 3158.1 7902 S = Slope % 2.31%S = Slope % 2.31%30 0.50 1.00 6.55 11789 3789.7 8000 35 0.58 0.91 5.93 12443 4421.3 8022Tc = 25.46MinutesTc = 15.53Minutes40 0.67 0.83 5.43 13038 5052.9 7985 45 0.75 0.77 5.03 13587 5684.5 7902Tc Shallow Concentrated Flow (After 400ft) Tc Shallow Concentrated Flow (After 400ft)50 0.83 0.72 4.70 14097 6316.1 7781V = KukSp0.5 (HEC 22 eqn 3-4) V = KukSp0.5 (HEC 22 eqn 3-4)55 0.92 0.68 4.42 14575 6947.7 7628 60 1.00 0.64 4.17 15026 7579.4 7447Ku = Conversion Factor3.28English UnitsKu = Conversion Factor3.28English Units65 1.08 0.61 3.96 15453 8211 7242k = Intercept Coefiicient 0.21HEC 22 Table 3-3k = Intercept Coefiicient 0.21HEC 22 Table 3-3Runoff Treatment Volume (Initial 0.5")Sp = Slope %2.31%Sp = Slope %1.61%Ia = 0.4 in0.5" - Ia=0.1 inV = 1.06ft/sV = 0.89ft/s515520.00ft2D = 680.00ftD = 1005.00ft4296ft3Tc =10.67MinutesTc =18.90Minutes8022ft3Total Tc (Overland and Shallow Concentrated) Total Tc (Overland and Shallow Concentrated)Outlet Structure Q = CLH3/2 (City of Bozeman Design Standards)Tc = 36.14 Minutes Tc = 34.43 MinutesQ = Discharge 1.67 cfsRunoff Rate (Intensity @ Tc) Runoff Rate (Intensity @ Tc)C = Weir Coefficient 3.33i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr) i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr)H = Head 1 ftx = storm duration (hrs.) 0.60hrs.x = storm duration (hrs.) 0.57hrs.i = 0.89in/hri = 0.92in/hrL = Weir Width 0.500 ftQ = CiAQ = 2.11cfsQ = CiAQ = 5.99cfsL = Weir Width6.00inches100-Year Storm Design Check:Storm Event (yr):2 10 25 100V100YR/2HR :29,795.98cf V100YR/24HR :67,653.07cf*Storm Coeff. A:0.36 0.64 0.78 1.01Pond Area:6,300.00sfPond Area:6,300.00sf*Storm Coeff. B: 0.60 0.65 0.64 0.67Infiltration Rate:4.00in/hr Infiltration Rate:4.00in/hrComposite C:0.55 0.55 0.55 0.55 Volume Infiltrated : 4,200.00 cf Volume Infiltrated : 50,400.00 cf2-Hr Storm Intensity (in/hr):0.24 0.41 0.50 0.63 Max Pond Storage: 8,430.00 cf Max Pond Storage: 8,430.00 cf24-Hr Storm Intensity (in/hr):0.05 0.08 0.10 0.12 Max Pond Capacity12,630.00cf Max Pond Capacity58,830.00cf2 Hr Post-Dev Qp (cfs):1.55 2.66 3.26 4.14 24 Hr Post-Dev Qp (cfs):0.35 0.53 0.67 0.78Area = Initial 0.5" Pond Volume Req. =Minimum Pond Size Required = Runoff Rate (City of Bozeman):100 Year StormOpen Land Open LandTotalsTotalsCW =CW =R.O.W.R.O.W.Dense Residential Dense ResidentialCommercial CommercialUrban + Farm Phase 2Basin C1 Detention Pond VolumeDesign Storm Frequency =Land UseC C*AreaLand UseC C*Area 10 yr Existing ConditionsProposed ConditionsBasin Sizing CalculationsWeighted C Value (Pre-Dev) Weighted C Value (Pre-Dev) Infiltration*Only used for 100-year analysisArea Area Area AreaObserved Percolation Rate 7.50 min/in(ft2) (acres) (ft2) (acres)8.00 in/hr 0.73 0.00 0.00 0.73 84048 1.93 1.410.50 0.00 0.00 0.50 194638 4.47 2.23 Design Percolation Rate 4.00 in/hr 0.60 0.00 0.00 0.60 98224 2.25 1.35 Infiltrative Area 6255ft20.20 452588 10.39 2.08 0.20 75522 1.73 0.35 Design Infiltration Rate 0.579 cfs 452588 10.39 2.08 452432 10.39 5.34Duration Duration Intensity Q Runoff Release Required0.200.51min hr in/hr cfs Volume Volume Storage 2 0.03 5.84 31.19 3743 227.7 3515Time To Concentration TcTime To Concentration Tc4 0.07 3.72 19.88 4771 455.4 4315Tc Overland Flow (Up to 400ft) Tc Overland Flow (Up to 400ft)6 0.10 2.86 15.27 5498 683.2 4815Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards) Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards)8 0.13 2.37 12.67 6081 910.9 517010 0.17 2.05 10.96 6574 1138.6 5436C = Weighted C Factor 0.20 C = Weighted C Factor 0.51 15 0.25 1.58 8.42 7577 1707.9 5869Cf = Frequency Factor1.00Cf = Frequency Factor1.00 20 0.33 1.31 6.98 8380 2277.2 6102D = Length 400.00ftD = Length 400.00ft25 0.42 1.13 6.04 9060 2846.5 6214 S = Slope % 2.31%S = Slope % 2.31%30 0.50 1.00 5.37 9657 3415.8 6241 35 0.58 0.91 4.85 10193 3985.1 6208Tc = 25.46MinutesTc = 16.57Minutes40 0.67 0.83 4.45 10680 4554.4 6126 45 0.75 0.77 4.12 11130 5123.7 6006Tc Shallow Concentrated Flow (After 400ft) Tc Shallow Concentrated Flow (After 400ft)50 0.83 0.72 3.85 11548 5693.0 5855V = KukSp0.5 (HEC 22 eqn 3-4) V = KukSp0.5 (HEC 22 eqn 3-4)55 0.92 0.68 3.62 11940 6262.3 5677 60 1.00 0.64 3.42 12309 6831.5 5477Ku = Conversion Factor3.28English UnitsKu = Conversion Factor3.28English Units65 1.08 0.61 3.25 12658 7401 5258k = Intercept Coefiicient 0.21HEC 22 Table 3-3k = Intercept Coefiicient 0.21HEC 22 Table 3-3Runoff Treatment Volume (Initial 0.5")Sp = Slope %2.31%Sp = Slope %1.61%Ia = 0.4 in0.5" - Ia=0.1 inV = 1.06ft/sV = 0.89ft/s452432.00ft2D = 590.00ftD = 710.00ft3770ft3Tc =9.26MinutesTc =13.35Minutes6241ft3Total Tc (Overland and Shallow Concentrated) Total Tc (Overland and Shallow Concentrated)Outlet Structure Q = CLH3/2 (City of Bozeman Design Standards)Tc = 34.72 Minutes Tc = 29.92 MinutesQ = Discharge 1.67 cfsRunoff Rate (Intensity @ Tc) Runoff Rate (Intensity @ Tc)C = Weir Coefficient 3.33i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr) i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr)H = Head 1 ftx = storm duration (hrs.) 0.58hrs.x = storm duration (hrs.) 0.50hrs.i = 0.91in/hri = 1.01in/hrL = Weir Width 0.500 ftQ = CiAQ = 1.90cfsQ = CiAQ = 5.37cfsL = Weir Width6.00inches100-Year Storm Design Check:Storm Event (yr):2 10 25 100V100YR/2HR :24,425.64cf V100YR/24HR :55,459.48cf*Storm Coeff. A:0.36 0.64 0.78 1.01Pond Area:6,255.00sfPond Area:6,255.00sf*Storm Coeff. B: 0.60 0.65 0.64 0.67Infiltration Rate:4.00in/hr Infiltration Rate:4.00in/hrComposite C:0.51 0.51 0.51 0.51 Volume Infiltrated : 4,170.00 cf Volume Infiltrated : 50,040.00 cf2-Hr Storm Intensity (in/hr):0.24 0.41 0.50 0.63 Max Pond Storage: 6,677.00 cf Max Pond Storage: 6,677.00 cf24-Hr Storm Intensity (in/hr):0.05 0.08 0.10 0.12 Max Pond Capacity10,847.00cf Max Pond Capacity56,717.00cf2 Hr Post-Dev Qp (cfs):1.27 2.18 2.67 3.39 24 Hr Post-Dev Qp (cfs):0.29 0.43 0.55 0.64Area = Initial 0.5" Pond Volume Req. =Minimum Pond Size Required = Runoff Rate (City of Bozeman):100 Year StormOpen Land Open LandTotalsTotalsCW =CW =R.O.W.R.O.W.Dense Residential Dense ResidentialCommercial CommercialUrban + Farm Phase 2Basin C2 Detention Pond VolumeDesign Storm Frequency =Land UseC C*AreaLand UseC C*Area 10 yr Existing ConditionsProposed ConditionsBasin Sizing CalculationsWeighted C Value (Pre-Dev) Weighted C Value (Pre-Dev) Infiltration*Only used for 100-year analysisArea Area Area AreaObserved Percolation Rate 7.50 min/in(ft2) (acres) (ft2) (acres)8.00 in/hr 0.73 0.00 0.00 0.73 0.00 0.00 0.50 0.00 0.00 0.50 40251 0.92 0.46 Design Percolation Rate 4.00 in/hr 0.60 0.00 0.00 0.60 0.00 0.00 Infiltrative Area 886ft20.20 40251 0.92 0.18 0.20 0.00 0.00 Design Infiltration Rate 0.082 cfs 40251 0.92 0.18 40251 0.92 0.46Duration Duration Intensity Q Runoff Release Required0.200.50min hr in/hr cfs Volume Volume Storage 2 0.03 5.84 2.70 324 23.5 300Time To Concentration TcTime To Concentration Tc4 0.07 3.72 1.72 413 46.9 366Tc Overland Flow (Up to 400ft) Tc Overland Flow (Up to 400ft)6 0.10 2.86 1.32 475 70.4 405Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards) Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards)8 0.13 2.37 1.10 526 93.9 43210 0.17 2.05 0.95 569 117.3 451C = Weighted C Factor 0.20 C = Weighted C Factor 0.50 15 0.25 1.58 0.73 655 176.0 479Cf = Frequency Factor1.00Cf = Frequency Factor1.00 20 0.33 1.31 0.60 725 234.7 490D = Length 265.00ftD = Length 318.00ft25 0.42 1.13 0.52 784 293.4 490S = Slope % 1.47%S = Slope % 1.47%30 0.50 1.00 0.46 835 352.0 48335 0.58 0.91 0.42 881 410.7 471Tc = 24.10MinutesTc = 17.60Minutes40 0.67 0.83 0.38 924 469.4 45445 0.75 0.77 0.36 963 528.1 434Tc Shallow Concentrated Flow (After 400ft) Tc Shallow Concentrated Flow (After 400ft)50 0.83 0.72 0.33 999 586.7 412V = KukSp0.5 (HEC 22 eqn 3-4) V = KukSp0.5 (HEC 22 eqn 3-4)55 0.92 0.68 0.31 1033 645.4 38760 1.00 0.64 0.30 1064 704.1 360Ku = Conversion Factor3.28English UnitsKu = Conversion Factor3.28English Units65 1.08 0.61 0.28 1095 763 332k = Intercept Coefiicient 0.21HEC 22 Table 3-3k = Intercept Coefiicient 0.21HEC 22 Table 3-3Runoff Treatment Volume (Initial 0.5")Sp = Slope %1.47%Sp = Slope %1.47%Ia = 0.4 in0.5" - Ia=0.1 inV = 0.85ft/sV = 0.85ft/s40251.00ft2D = 182.00ftD = 250.00ft335ft3Tc =3.58MinutesTc =4.92Minutes490ft3Total Tc (Overland and Shallow Concentrated) Total Tc (Overland and Shallow Concentrated)Outlet Structure Q = CLH3/2 (City of Bozeman Design Standards)Tc = 27.68 Minutes Tc = 22.52 MinutesQ = Discharge 0.20 cfsRunoff Rate (Intensity @ Tc) Runoff Rate (Intensity @ Tc)C = Weir Coefficient 3.33i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr) i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr)H = Head 0.5 ftx = storm duration (hrs.) 0.46hrs.x = storm duration (hrs.) 0.38hrs.i = 1.06in/hri = 1.21in/hrL = Weir Width 0.167 ftQ = CiAQ = 0.20cfsQ = CiAQ = 0.56cfsL = Weir Width2.00inches100-Year Storm Design Check:Storm Event (yr):2 10 25 100V100YR/2HR :2,111.65cf V100YR/24HR :4,794.60cf*Storm Coeff. A:0.36 0.64 0.78 1.01Pond Area:886.00sfPond Area:886.00sf*Storm Coeff. B: 0.60 0.65 0.64 0.67Infiltration Rate:4.00in/hr Infiltration Rate:4.00in/hrComposite C:0.50 0.50 0.50 0.50 Volume Infiltrated : 590.67 cf Volume Infiltrated : 7,088.00 cf2-Hr Storm Intensity (in/hr):0.24 0.41 0.50 0.63 Max Pond Storage: 1,450.00 cf Max Pond Storage: 1,450.00 cf24-Hr Storm Intensity (in/hr):0.05 0.08 0.10 0.12 Max Pond Capacity2,040.67cf Max Pond Capacity8,538.00cf2 Hr Post-Dev Qp (cfs):0.11 0.19 0.23 0.29 24 Hr Post-Dev Qp (cfs):0.02 0.04 0.05 0.06Urban + Farm Phase 2Basin D1 Detention Pond VolumeDesign Storm Frequency =Land UseC C*AreaLand UseC C*AreaCW =R.O.W.R.O.W.Dense Residential Dense ResidentialCommercial Commercial Area = Initial 0.5" Pond Volume Req. =Minimum Pond Size Required = Runoff Rate (City of Bozeman):100 Year StormOpen Land Open LandTotalsTotalsCW = 10 yr Existing ConditionsProposed ConditionsBasin Sizing CalculationsWeighted C Value (Pre-Dev) Weighted C Value (Pre-Dev) Infiltration*Only used for 100-year analysisArea Area Area AreaObserved Percolation Rate 7.50 min/in(ft2) (acres) (ft2) (acres)8.00 in/hr 0.73 0.00 0.00 0.73 17661 0.41 0.300.50 0.00 0.00 0.50 0.00 0.00 Design Percolation Rate 4.00 in/hr0.60 0.00 0.00 0.60 44701 1.03 0.62 Infiltrative Area 502ft20.20 62362 1.43 0.29 0.20 0.00 0.00 Design Infiltration Rate 0.046 cfs 62362 1.43 0.29 62362 1.43 0.91Duration Duration Intensity Q Runoff Release Required0.200.64min hr in/hr cfs Volume Volume Storage 2 0.03 5.84 5.32 639 34.9 604Time To Concentration TcTime To Concentration Tc4 0.07 3.72 3.39 814 69.8 744Tc Overland Flow (Up to 400ft) Tc Overland Flow (Up to 400ft)6 0.10 2.86 2.61 938 104.7 834Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards) Tc = 1.87(1.1-CCf)D0.5)/S1/3 (City of Bozeman Design Standards)8 0.13 2.37 2.16 1038 139.6 89810 0.17 2.05 1.87 1122 174.5 947C = Weighted C Factor 0.20 C = Weighted C Factor 0.64 15 0.25 1.58 1.44 1293 261.7 1031Cf = Frequency Factor1.00Cf = Frequency Factor1.00 20 0.33 1.31 1.19 1430 349.0 1081D = Length 300.00ftD = Length 300.00ft25 0.42 1.13 1.03 1546 436.2 1110S = Slope % 1.46%S = Slope % 1.46%30 0.50 1.00 0.92 1648 523.4 112535 0.58 0.91 0.83 1739 610.7 1129Tc = 25.70MinutesTc = 13.22Minutes40 0.67 0.83 0.76 1823 697.9 112545 0.75 0.77 0.70 1899 785.1 1114Tc Shallow Concentrated Flow (After 400ft) Tc Shallow Concentrated Flow (After 400ft)50 0.83 0.72 0.66 1971 872.4 1098V = KukSp0.5 (HEC 22 eqn 3-4) V = KukSp0.5 (HEC 22 eqn 3-4)55 0.92 0.68 0.62 2038 959.6 107860 1.00 0.64 0.58 2101 1046.9 1054Ku = Conversion Factor3.28English UnitsKu = Conversion Factor3.28English Units65 1.08 0.61 0.55 2160 1134 1026k = Intercept Coefiicient 0.21HEC 22 Table 3-3k = Intercept Coefiicient 0.21HEC 22 Table 3-3Runoff Treatment Volume (Initial 0.5")Sp = Slope %1.46%Sp = Slope %1.46%Ia = 0.4 in0.5" - Ia=0.1 inV = 0.84ft/sV = 0.84ft/s62362.00ft2D = 192.00ftD = 250.00ft520ft3Tc =3.79MinutesTc =4.94Minutes1129ft3Total Tc (Overland and Shallow Concentrated) Total Tc (Overland and Shallow Concentrated)Outlet Structure Q = CLH3/2 (City of Bozeman Design Standards)Tc = 29.49 Minutes Tc = 18.16 MinutesQ = Discharge 0.29 cfsRunoff Rate (Intensity @ Tc) Runoff Rate (Intensity @ Tc)C = Weir Coefficient 3.33i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr) i = 0.64x-0.65 (COB Design Standards, Fig. I-3, 10 yr)H = Head 0.5 ftx = storm duration (hrs.) 0.49hrs.x = storm duration (hrs.) 0.30hrs.i = 1.02in/hri = 1.39in/hrL = Weir Width 0.250 ftQ = CiAQ = 0.29cfsQ = CiAQ = 1.27cfsL = Weir Width3.00inches100-Year Storm Design Check:Storm Event (yr):2 10 25 100V100YR/2HR :4,166.87cf V100YR/24HR :9,461.06cf*Storm Coeff. A:0.36 0.64 0.78 1.01Pond Area:502.00sfPond Area:502.00sf*Storm Coeff. B: 0.60 0.65 0.64 0.67Infiltration Rate:4.00in/hr Infiltration Rate:4.00in/hrComposite C:0.64 0.64 0.64 0.64 Volume Infiltrated : 334.67 cf Volume Infiltrated : 4,016.00 cf2-Hr Storm Intensity (in/hr):0.24 0.41 0.50 0.63 Max Pond Storage: 1,450.00 cf Max Pond Storage: 1,450.00 cf24-Hr Storm Intensity (in/hr):0.05 0.08 0.10 0.12 Max Pond Capacity1,784.67cf Max Pond Capacity5,466.00cf2 Hr Post-Dev Qp (cfs):0.22 0.37 0.46 0.58 24 Hr Post-Dev Qp (cfs):0.05 0.07 0.09 0.11Urban + Farm Phase 2Basin D2 Detention Pond VolumeDesign Storm Frequency =Land UseC C*AreaLand UseC C*AreaCW =R.O.W.R.O.W.Dense Residential Dense ResidentialCommercial Commercial Area = Initial 0.5" Pond Volume Req. =Minimum Pond Size Required = Runoff Rate (City of Bozeman):100 Year StormOpen Land Open LandTotalsTotalsCW = 10yrBasin Area (ac):0.6729,185.20 (sq ft)Post-Dev C (weighted):0.55Storm Duration (min)120.00Area Runoff (acres) Coefficient CalculationsR.O.W.0.14 0.73 0.10Dense Residential0.53 0.50 0.27Open Land0.00 0.20 0.00Totals0.67 0.37C w =0.55Storm Event (yr):2-yr, 2-hr 10-yr, 2-hr 25-yr, 2-hr 100-yr, 2-hr 100-yr, 24-hr*Storm Coeff. A:0.36 0.64 0.78 1.01 1.01*Storm Coeff. B:0.60 0.65 0.64 0.67 0.67Composite C:0.55 0.55 0.55 0.55 0.55Storm Intensity (in/hr):0.24 0.41 0.50 0.63 0.12Post-Dev Qp (cfs):0.09 0.15 0.18 0.23 0.04V100YR/2HR :1,678.29cf V100YR/24HR :3,810.63cf10-Year, 2 Hour StormPond Area:590.00sfPond Area:590.00sfDuration Time:7,200.00sec Infiltration Rate:4.00in/hr Infiltration Rate:2.00in/hrV10YR/2HR :1,078cfVolume Infiltrated :393.33cf Volume Infiltrated :2,360.00cfMax Pond Storage: 1,254.00cf Max Pond Storage: 1,254.00cfMax Pond Capacity 1,647.33 cf Max Pond Capacity 3,614.00 cfCN= 85S= 1.8 inIa = 0.4 in0.5" - Ia=0.1 inV1/2":358 cf*Values are from COB Design Standards Figure 2 - Rainfall Intensity Duration in MinutesPond Size: 100 Year Storm (Includes Infiltration)Runoff Treatment Volume (Initial 0.5"):Urban + Farm Phase 2Retention Pond EDesign Storm Frequency =Design Storm: 10-Year, 2-Hour (City of Bozeman)Weighted Runoff Co-efficent:Runoff Rate (Rational Method): 10yrBasin Area (ac):0.146,098.40 (sq ft)Post-Dev C (weighted):0.71Storm Duration (min)120.00Area Runoff (acres) Coefficient CalculationsR.O.W.0.13 0.73 0.09Dense Residential0.01 0.50 0.01Open Land0.00 0.20 0.00Totals0.14 0.10C w =0.71Storm Event (yr):2-yr, 2-hr 10-yr, 2-hr 25-yr, 2-hr 100-yr, 2-hr 100-yr, 24-hr*Storm Coeff. A:0.36 0.64 0.78 1.01 1.01*Storm Coeff. B:0.60 0.65 0.64 0.67 0.67Composite C:0.71 0.71 0.71 0.71 0.71Storm Intensity (in/hr):0.24 0.41 0.50 0.63 0.12Post-Dev Qp (cfs):0.02 0.04 0.05 0.06 0.01V100YR/2HR :456.59cf V100YR/24HR :1,036.71cf10-Year, 2 Hour StormPond Area:210.00sfPond Area:210.00sfDuration Time:7,200.00sec Infiltration Rate:4.00in/hr Infiltration Rate:2.00in/hrV10YR/2HR :293cfVolume Infiltrated :140.00cf Volume Infiltrated :840.00cfMax Pond Storage: 297.00cf Max Pond Storage: 297.00cfMax Pond Capacity 437.00 cf Max Pond Capacity 1,137.00 cf CN= 85S= 1.8 inIa = 0.4 in0.5" - Ia=0.1 inV1/2":75 cf *Values are from COB Design Standards Figure 2 - Rainfall Intensity Duration in MinutesPond Size: 100 Year Storm (Includes Infiltration)Runoff Treatment Volume (Initial 0.5"):Urban + Farm Phase 2Retention Pond FDesign Storm Frequency =Design Storm: 10-Year, 2-Hour (City of Bozeman)Weighted Runoff Co-efficent:Runoff Rate (Rational Method): Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2023 Monday, 11 / 20 / 2023 Pond No. 1 - Pond A Pond Data UG Chambers -Invert elev. = 4810.00 ft, Rise x Span = 2.50 x 2.50 ft, Barrel Len = 285.00 ft, No. Barrels = 14, Slope = 0.00%, Headers = Yes Encasement -Invert elev. = 4809.00 ft, Width = 4.50 ft, Height = 3.50 ft, Voids = 40.00% Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 4809.00 n/a 0 0 0.35 4809.35 n/a 2,594 2,594 0.70 4809.70 n/a 2,594 5,187 1.05 4810.05 n/a 2,651 7,838 1.40 4810.40 n/a 3,788 11,626 1.75 4810.75 n/a 4,402 16,029 2.10 4811.10 n/a 4,675 20,704 2.45 4811.45 n/a 4,747 25,451 2.80 4811.80 n/a 4,644 30,095 3.15 4812.15 n/a 4,342 34,437 3.50 4812.50 n/a 3,624 38,061 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 0.00 0.00 0.00 0.00 Span (in)= 0.00 0.00 0.00 0.00 No. Barrels = 0 0 0 0 Invert El. (ft)= 0.00 0.00 0.00 0.00 Length (ft)= 0.00 0.00 0.00 0.00 Slope (%)= 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a No No No Crest Len (ft)= 0.75 0.00 0.00 0.00 Crest El. (ft)= 4811.00 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = Rect --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Wet area) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 4809.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.35 2,594 4809.35 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.70 5,187 4809.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.05 7,838 4810.05 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.40 11,626 4810.40 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.75 16,029 4810.75 --- --- --- --- 0.00 --- --- --- --- --- 0.000 2.10 20,704 4811.10 --- --- --- --- 0.08 --- --- --- --- --- 0.079 2.45 25,451 4811.45 --- --- --- --- 0.75 --- --- --- --- --- 0.754 2.80 30,095 4811.80 --- --- --- --- 1.79 --- --- --- --- --- 1.786 3.15 34,437 4812.15 --- --- --- --- 3.08 --- --- --- --- --- 3.080 3.50 38,061 4812.50 --- --- --- --- 4.59 --- --- --- --- --- 4.588 Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2023 Monday, 11 / 20 / 2023 Pond No. 2 - Pond C1 Pond Data UG Chambers -Invert elev. = 4821.00 ft, Rise x Span = 2.00 x 2.00 ft, Barrel Len = 100.00 ft, No. Barrels = 19, Slope = 0.00%, Headers = Yes Encasement -Invert elev. = 4820.00 ft, Width = 4.00 ft, Height = 3.00 ft, Voids = 40.00% Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 4820.00 n/a 0 0 0.30 4820.30 n/a 985 985 0.60 4820.60 n/a 985 1,970 0.90 4820.90 n/a 985 2,955 1.20 4821.20 n/a 1,187 4,142 1.50 4821.50 n/a 1,540 5,683 1.80 4821.80 n/a 1,673 7,356 2.10 4822.10 n/a 1,721 9,077 2.40 4822.40 n/a 1,697 10,774 2.70 4822.70 n/a 1,598 12,372 3.00 4823.00 n/a 1,348 13,720 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 0.00 0.00 0.00 0.00 Span (in)= 0.00 0.00 0.00 0.00 No. Barrels = 0 0 0 0 Invert El. (ft)= 0.00 0.00 0.00 0.00 Length (ft)= 0.00 0.00 0.00 0.00 Slope (%)= 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a No No No Crest Len (ft)= 0.50 0.00 0.00 0.00 Crest El. (ft)= 4822.00 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = Rect --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Wet area) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 4820.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.30 985 4820.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.60 1,970 4820.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.90 2,955 4820.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.20 4,142 4821.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.50 5,683 4821.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.80 7,356 4821.80 --- --- --- --- 0.00 --- --- --- --- --- 0.000 2.10 9,077 4822.10 --- --- --- --- 0.05 --- --- --- --- --- 0.053 2.40 10,774 4822.40 --- --- --- --- 0.42 --- --- --- --- --- 0.421 2.70 12,372 4822.70 --- --- --- --- 0.98 --- --- --- --- --- 0.976 3.00 13,720 4823.00 --- --- --- --- 1.66 --- --- --- --- --- 1.665 Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2023 Monday, 11 / 20 / 2023 Pond No. 3 - Pond C2 Pond Data UG Chambers -Invert elev. = 4814.70 ft, Rise x Span = 2.00 x 2.00 ft, Barrel Len = 455.00 ft, No. Barrels = 4, Slope = 0.00%, Headers = Yes Encasement -Invert elev. = 4813.70 ft, Width = 4.00 ft, Height = 3.00 ft, Voids = 40.00% Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 4813.70 n/a 0 0 0.30 4814.00 n/a 889 889 0.60 4814.30 n/a 889 1,778 0.90 4814.60 n/a 889 2,667 1.20 4814.90 n/a 1,071 3,739 1.50 4815.20 n/a 1,390 5,129 1.80 4815.50 n/a 1,510 6,639 2.10 4815.80 n/a 1,554 8,193 2.40 4816.10 n/a 1,531 9,724 2.70 4816.40 n/a 1,442 11,166 3.00 4816.70 n/a 1,217 12,383 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 0.00 0.00 0.00 0.00 Span (in)= 0.00 0.00 0.00 0.00 No. Barrels = 0 0 0 0 Invert El. (ft)= 0.00 0.00 0.00 0.00 Length (ft)= 0.00 0.00 0.00 0.00 Slope (%)= 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a No No No Crest Len (ft)= 0.50 0.00 0.00 0.00 Crest El. (ft)= 4815.70 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = Rect --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Wet area) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 4813.70 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.30 889 4814.00 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.60 1,778 4814.30 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.90 2,667 4814.60 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.20 3,739 4814.90 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.50 5,129 4815.20 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.80 6,639 4815.50 --- --- --- --- 0.00 --- --- --- --- --- 0.000 2.10 8,193 4815.80 --- --- --- --- 0.05 --- --- --- --- --- 0.053 2.40 9,724 4816.10 --- --- --- --- 0.42 --- --- --- --- --- 0.421 2.70 11,166 4816.40 --- --- --- --- 0.98 --- --- --- --- --- 0.976 3.00 12,383 4816.70 --- --- --- --- 1.66 --- --- --- --- --- 1.665 Pond Report Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2023 Monday, 11 / 20 / 2023 Pond No. 4 - Pond D Pond Data Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 4817.25 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cuft) 0.00 4817.25 600 0 0 0.50 4817.75 975 390 390 1.00 4818.25 1,365 582 972 1.50 4818.75 1,771 782 1,754 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in)= 0.00 0.00 0.00 0.00 Span (in)= 0.00 0.00 0.00 0.00 No. Barrels = 0 0 0 0 Invert El. (ft)= 0.00 0.00 0.00 0.00 Length (ft)= 0.00 0.00 0.00 0.00 Slope (%)= 0.00 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff.= 0.60 0.60 0.60 0.60 Multi-Stage = n/a No No No Crest Len (ft)= 0.33 0.00 0.00 0.00 Crest El. (ft)= 4818.25 0.00 0.00 0.00 Weir Coeff.= 3.33 3.33 3.33 3.33 Weir Type = Rect --- --- --- Multi-Stage = No No No No Exfil.(in/hr)= 0.000 (by Wet area) TW Elev. (ft)= 0.00 Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage / Storage / Discharge Table Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 4817.25 --- --- --- --- 0.00 --- --- --- --- --- 0.000 0.50 390 4817.75 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.00 972 4818.25 --- --- --- --- 0.00 --- --- --- --- --- 0.000 1.50 1,754 4818.75 --- --- --- --- 0.39 --- --- --- --- --- 0.389 0.90 0.50 0.60 0.20 Note: Coefficients obtained from CoB Design Standards Table I-1 BASIN SDI-1A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 17131.458 0.39 0.73 0.29 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 28671.237 0.66 0.20 0.13 Totals 45802.695 1.05 0.42 Cw =0.40 BASIN SDI-2A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14188.715 0.33 0.73 0.24 Dense Residential 78790.091 1.81 0.50 0.90 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 92978.8 2.13 1.14 Cw =0.54 BASIN SDI-3A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 11693.065 0.27 0.73 0.20 Dense Residential 83159.417 1.91 0.50 0.95 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 94852.5 2.18 1.15 Cw =0.53 BASIN SDI-4A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 33137.22 0.76 0.73 0.56 Dense Residential 71787.48 1.65 0.50 0.82 Commercial 0 0.00 0.60 0.00 Open Land 28848.49 0.66 0.20 0.13 Totals 133773.19 3.07 1.51 Cw =0.49 MAJOR SUBDIVISION Weighted Runoff Coefficients URBAN + FARM PHASE 2 - BASIN A Asphalt/Concrete Dense Residential Open Land Commercial Neighborhood L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-5A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 16075.44 0.37 0.73 0.27 Dense Residential 62244.254 1.43 0.50 0.71 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 78319.7 1.80 0.98 Cw =0.55 BASIN SDI-6A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14904.38 0.34 0.73 0.25 Dense Residential 22354.22 0.51 0.50 0.26 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 37258.6 0.86 0.51 Cw =0.59 BASIN SDI-7A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 9444.42 0.22 0.73 0.16 Dense Residential 55952.76 1.28 0.50 0.64 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 65397.2 1.50 0.80 Cw =0.53 BASIN SDI-8A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14224.08 0.33 0.73 0.24 Dense Residential 94197.47 2.16 0.50 1.08 Commercial 0 0.00 0.60 0.00 Open Land 25011.01 0.57 0.20 0.11 Totals 133432.6 3.06 1.43 Cw =0.47 BASIN SDI-9A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14032.062 0.32 0.73 0.24 Dense Residential 78663.183 1.81 0.50 0.90 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 92695.2 2.13 1.14 Cw =0.53 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-10A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 19983.61 0.46 0.73 0.33 Dense Residential 161814.43 3.71 0.50 1.86 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 181798.0 4.17 2.19 Cw =0.53 BASIN SDI-11A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 12943.9 0.30 0.73 0.22 Dense Residential 85151.86 1.95 0.50 0.98 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 98095.8 2.25 1.19 Cw =0.53 BASIN SDI-12A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 28600 0.66 0.73 0.48 Dense Residential 69663.84 1.60 0.50 0.80 Commercial 0 0.00 0.60 0.00 Open Land 6419 0.15 0.20 0.03 Totals 104682.84 2.40 1.31 Cw =0.54 BASIN SDI-13A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 15199.45 0.35 0.73 0.25 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 15199.5 0.35 0.25 Cw =0.73 BASIN SDI-14A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 43414.85 1.00 0.73 0.73 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 77802.9 1.79 0.20 0.36 Totals 121217.8 2.78 1.08 Cw =0.39 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-15A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 2427.3 0.06 0.73 0.04 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 2427.3 0.06 0.04 Cw =0.73 BASIN SDI-16A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 28000.25 0.64 0.73 0.47 Dense Residential 68760.68 1.58 0.50 0.79 Commercial 0 0.00 0.60 0.00 Open Land 6303.06 0.14 0.20 0.03 Totals 103063.99 2.37 1.29 Cw =0.54 BASIN SDI-17A Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 35133.72 0.81 0.73 0.59 Dense Residential 86359.82 1.98 0.50 0.99 Commercial 0 0.00 0.60 0.00 Open Land 9694.17 0.22 0.20 0.04 Totals 131187.71 3.01 1.62 Cw =0.54 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Equations Used: Qp = C i A (Modified Rational Method) i = a * (DURATION) ^ -(b) (City of Bozeman) Overland Flow tc=((1.8)*(1.1-C)*(D^(1/2)))/(S^(1/3)) (City of Bozeman) Gutter Flow V=3.28*k*(S^(1/2), where k=0.618 (paved) (FHWA HEC 22, Eqn 3-4) BASIN 1A Basin Area (ac): 1.05 Storm Event Intensity Post-Dev C (weighted): 0.40 (yr) (in/hr)A B Overland Distance (ft): 72.5 2 0.77 0.36 0.6 Overland Slope (%): 1.0 5 1.17 0.52 0.64 Gutter Flow Distance (ft): 528.0 10 1.46 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.76 0.78 0.64 Post-Dev. Tc (min): 16.9 50 2.12 0.92 0.66 Post-Dev Tc (hr): 0.28 100 2.36 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.40 0.40 0.40 0.40 Storm Intensity (in/hr): 0.77 1.46 1.76 2.36 Post-Dev Qp (cfs):0.32 0.61 0.73 0.99 BASIN 2A Basin Area (ac): 2.13 Storm Event Intensity Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 305.5 2 0.69 0.36 0.6 Overland Slope (%): 1.0 5 1.04 0.52 0.64 Gutter Flow Distance (ft): 318.0 10 1.29 0.64 0.65 Gutter Flow Slope (%): 1.02 25 1.56 0.78 0.64 Post-Dev. Tc (min): 20.4 50 1.88 0.92 0.66 Post-Dev Tc (hr.): 0.34 100 2.08 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.69 1.29 1.56 2.08 Post-Dev Qp (cfs):0.79 1.48 1.78 2.38 BASIN 3A Basin Area (ac): 2.18 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 286 2 0.70 0.36 0.6 Overland Slope (%): 1.0 5 1.06 0.52 0.64 Gutter Flow Distance (ft): 243.0 10 1.32 0.64 0.65 Gutter Flow Slope (%): 0.75 25 1.59 0.78 0.64 Post-Dev. Tc (min): 19.7 50 1.92 0.92 0.66 Post-Dev Tc (hr.): 0.33 100 2.13 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.70 1.32 1.59 2.13 Post-Dev Qp (cfs):0.81 1.52 1.83 2.45 BASIN 4A Basin Area (ac): 3.07 Storm Event Intensity Post-Dev C (weighted): 0.49 (yr) (in/hr)A B Overland Distance (ft): 410 2 0.61 0.36 0.6 Overland Slope (%): 1.0 5 0.92 0.52 0.64 Gutter Flow Distance (ft): 222.0 10 1.14 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.38 0.78 0.64 Post-Dev. Tc (min): 24.7 50 1.65 0.92 0.66 Post-Dev Tc (hr.): 0.41 100 1.83 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.49 0.49 0.49 0.49 Storm Intensity (in/hr): 0.61 1.14 1.38 1.83 Post-Dev Qp (cfs):0.93 1.72 2.08 2.77 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) URBAN + FARM PHASE 2 - BASIN A POST-DEVELOPMENT SUB BASIN FLOWS MAJOR SUBDIVISION Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 5A Basin Area (ac): 1.80 Storm Event Intensity Post-Dev C (weighted): 0.55 (yr) (in/hr)A B Overland Distance (ft): 327.5 2 0.63 0.36 0.6 Overland Slope (%): 1.0 5 0.95 0.52 0.64 Gutter Flow Distance (ft): 496.0 10 1.18 0.64 0.65 Gutter Flow Slope (%): 0.57 25 1.42 0.78 0.64 Post-Dev. Tc (min): 23.4 50 1.71 0.92 0.66 Post-Dev Tc (hr.): 0.39 100 1.90 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.55 0.55 0.55 0.55 Storm Intensity (in/hr): 0.63 1.18 1.42 1.90 Post-Dev Qp (cfs):0.62 1.16 1.40 1.87 BASIN 6A Basin Area (ac): 0.86 Storm Event Intensity Post-Dev C (weighted): 0.59 (yr) (in/hr)A B Overland Distance (ft): 60 2 0.93 0.36 0.6 Overland Slope (%): 1.0 5 1.43 0.52 0.64 Gutter Flow Distance (ft): 478.0 10 1.79 0.64 0.65 Gutter Flow Slope (%): 0.57 25 2.15 0.78 0.64 Post-Dev. Tc (min): 12.3 50 2.62 0.92 0.66 Post-Dev Tc (hr.): 0.20 100 2.92 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.59 0.59 0.59 0.59 Storm Intensity (in/hr): 0.93 1.79 2.15 2.92 Post-Dev Qp (cfs):0.47 0.91 1.09 1.48 BASIN 7A Basin Area (ac): 1.50 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 476 2 0.61 0.36 0.6 Overland Slope (%): 1.0 5 0.92 0.52 0.64 Gutter Flow Distance (ft): 238.0 10 1.14 0.64 0.65 Gutter Flow Slope (%): 0.59 25 1.37 0.78 0.64 Post-Dev. Tc (min): 24.8 50 1.65 0.92 0.66 Post-Dev Tc (hr.): 0.41 100 1.83 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.61 1.14 1.37 1.83 Post-Dev Qp (cfs):0.49 0.91 1.10 1.46 BASIN 8A Basin Area (ac): 3.06 Storm Event Intensity Post-Dev C (weighted): 0.47 (yr) (in/hr)A B Overland Distance (ft): 530 2 0.56 0.36 0.6 Overland Slope (%): 1.0 5 0.83 0.52 0.64 Gutter Flow Distance (ft): 382.0 10 1.02 0.64 0.65 Gutter Flow Slope (%): 1.15 25 1.24 0.78 0.64 Post-Dev. Tc (min): 29.1 50 1.48 0.92 0.66 Post-Dev Tc (hr.): 0.49 100 1.64 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.47 0.47 0.47 0.47 Storm Intensity (in/hr): 0.56 1.02 1.24 1.64 Post-Dev Qp (cfs):0.80 1.47 1.78 2.35 BASIN 9A Basin Area (ac): 2.13 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 298 2 0.69 0.36 0.6 Overland Slope (%): 1.0 5 1.04 0.52 0.64 Gutter Flow Distance (ft): 370.0 10 1.29 0.64 0.65 Gutter Flow Slope (%): 1.15 25 1.56 0.78 0.64 Post-Dev. Tc (min): 20.4 50 1.88 0.92 0.66 Post-Dev Tc (hr.): 0.34 100 2.08 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Storm Intensity (in/hr): 0.69 1.29 1.56 2.08 Post-Dev Qp (cfs):0.78 1.47 1.77 2.37 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 10A Basin Area (ac): 4.17 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 366 2 0.61 0.36 0.6 Overland Slope (%): 1.0 5 0.91 0.52 0.64 Gutter Flow Distance (ft): 609.0 10 1.13 0.64 0.65 Gutter Flow Slope (%): 0.90 25 1.36 0.78 0.64 Post-Dev. Tc (min): 25.1 50 1.64 0.92 0.66 Post-Dev Tc (hr.): 0.42 100 1.81 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.61 1.13 1.36 1.81 Post-Dev Qp (cfs):1.33 2.47 2.99 3.97 BASIN 11A Basin Area (ac): 2.25 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 285 2 0.71 0.36 0.6 Overland Slope (%): 1.0 5 1.08 0.52 0.64 Gutter Flow Distance (ft): 263.5 10 1.34 0.64 0.65 Gutter Flow Slope (%): 1.25 25 1.61 0.78 0.64 Post-Dev. Tc (min): 19.2 50 1.95 0.92 0.66 Post-Dev Tc (hr.): 0.32 100 2.16 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.71 1.34 1.61 2.16 Post-Dev Qp (cfs):0.85 1.60 1.93 2.58 BASIN 12A Basin Area (ac): 2.40 Storm Event Intensity Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 399 2 0.66 0.36 0.6 Overland Slope (%): 1.0 5 0.99 0.52 0.64 Gutter Flow Distance (ft): 167.0 10 1.23 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.49 0.78 0.64 Post-Dev. Tc (min): 21.9 50 1.79 0.92 0.66 Post-Dev Tc (hr.): 0.37 100 1.98 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.66 1.23 1.49 1.98 Post-Dev Qp (cfs):0.86 1.61 1.94 2.59 BASIN 13A Basin Area (ac): 0.35 Storm Event Intensity Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 14 2 1.18 0.36 0.6 Overland Slope (%): 1.0 5 1.84 0.52 0.64 Gutter Flow Distance (ft): 500.0 10 2.31 0.64 0.65 Gutter Flow Slope (%): 0.50 25 2.77 0.78 0.64 Post-Dev. Tc (min): 8.3 50 3.39 0.92 0.66 Post-Dev Tc (hr.): 0.14 100 3.80 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.18 2.31 2.77 3.80 Post-Dev Qp (cfs):0.30 0.59 0.70 0.97 BASIN 14A Basin Area (ac): 2.78 Storm Event Intensity Post-Dev C (weighted): 0.39 (yr) (in/hr)A B Overland Distance (ft): 412.5 2 0.51 0.36 0.6 Overland Slope (%): 1.0 5 0.76 0.52 0.64 Gutter Flow Distance (ft): 857.0 10 0.94 0.64 0.65 Gutter Flow Slope (%): 0.90 25 1.13 0.78 0.64 Post-Dev. Tc (min): 33.4 50 1.35 0.92 0.66 Post-Dev Tc (hr.): 0.56 100 1.50 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.39 0.39 0.39 0.39 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Storm Intensity (in/hr): 0.51 0.94 1.13 1.50 Post-Dev Qp (cfs):0.56 1.02 1.23 1.62 BASIN 15A Basin Area (ac): 0.06 Storm Event Intensity Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 15 2 2.23 0.36 0.6 Overland Slope (%): 1.0 5 3.64 0.52 0.64 Gutter Flow Distance (ft): 34.5 10 4.62 0.64 0.65 Gutter Flow Slope (%): 1.00 25 5.47 0.78 0.64 Post-Dev. Tc (min): 2.9 50 6.85 0.92 0.66 Post-Dev Tc (hr.): 0.05 100 7.76 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 2.23 4.62 5.47 7.76 Post-Dev Qp (cfs):0.09 0.19 0.22 0.32 BASIN 16A Basin Area (ac): 2.37 Storm Event Intensity Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 399 2 0.66 0.36 0.6 Overland Slope (%): 1.0 5 0.99 0.52 0.64 Gutter Flow Distance (ft): 159.5 10 1.23 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.49 0.78 0.64 Post-Dev. Tc (min): 21.8 50 1.79 0.92 0.66 Post-Dev Tc (hr.): 0.36 100 1.99 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.66 1.23 1.49 1.99 Post-Dev Qp (cfs):0.85 1.59 1.92 2.56 BASIN 17A Basin Area (ac): 3.01 Storm Event Intensity Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 400.5 2 0.64 0.36 0.6 Overland Slope (%): 1.0 5 0.97 0.52 0.64 Gutter Flow Distance (ft): 224.0 10 1.20 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.45 0.78 0.64 Post-Dev. Tc (min): 22.8 50 1.74 0.92 0.66 Post-Dev Tc (hr.): 0.38 100 1.93 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.64 1.20 1.45 1.93 Post-Dev Qp (cfs):1.05 1.95 2.35 3.14 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls 0.90 0.50 0.60 0.20 Note: Coefficients obtained from CoB Design Standards Table I-1 BASIN SDI-4B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 19730.889 0.45 0.73 0.33 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 31327.772 0.72 0.20 0.14 Totals 51058.7 1.17 0.47 Cw =0.40 BASIN SDI-5B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 21101.9 0.48 0.73 0.35 Dense Residential 57095.72 1.31 0.50 0.66 Commercial 0 0.00 0.60 0.00 Open Land 7449.88 0.17 0.20 0.03 Totals 85647.5 1.97 1.04 Cw =0.53 BASIN SDI-6B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 13202.151 0.30 0.73 0.22 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 43215.797 0.99 0.20 0.20 Totals 56417.9 1.30 0.42 Cw =0.32 Open Land URBAN + FARM PHASE 2 - BASIN B MAJOR SUBDIVISION Weighted Runoff Coefficients Asphalt/Concrete Dense Residential Commercial Neighborhood L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-7B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 8463.26 0.19 0.73 0.14 Dense Residential 49673.47 1.14 0.50 0.57 Commercial 0 0.00 0.60 0.00 Open Land 645.5 0.01 0.20 0.00 Totals 58782.2 1.35 0.71 Cw =0.53 BASIN SDI-8B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 8119.24 0.19 0.73 0.14 Dense Residential 82659 1.90 0.50 0.95 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 90778.2 2.08 1.08 Cw =0.52 BASIN SDI-9B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 18440.35 0.42 0.73 0.31 Dense Residential 50427.14 1.16 0.50 0.58 Commercial 0 0.00 0.60 0.00 Open Land 4659.94 0.11 0.20 0.02 Totals 73527.43 1.69 0.91 Cw =0.54 BASIN SDI-10B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 8525.88 0.20 0.73 0.14 Dense Residential 21723.98 0.50 0.50 0.25 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 30249.9 0.69 0.39 Cw =0.56 BASIN SDI-11B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 15119.93 0.35 0.73 0.25 Dense Residential 17502.7 0.40 0.50 0.20 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 32622.6 0.75 0.45 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Cw =0.61 BASIN SDI-12B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 13047.577 0.30 0.73 0.22 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 13047.6 0.30 0.22 Cw =0.73 BASIN SDI-13B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14142.952 0.32 0.73 0.24 Dense Residential 4958.76 0.11 0.50 0.06 Commercial 0 0.00 0.60 0.00 Open Land 28638.511 0.66 0.20 0.13 Totals 47740.2 1.10 0.43 Cw =0.39 BASIN SDI-14B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 5818.1 0.13 0.73 0.10 Dense Residential 26144.032 0.60 0.50 0.30 Commercial 26045.755 0.60 0.60 0.36 Open Land 0 0.00 0.20 0.00 Totals 58007.9 1.33 0.76 Cw =0.57 BASIN SDI-15B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 4689.36 0.11 0.73 0.08 Dense Residential 24162.95 0.55 0.50 0.28 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 28852.3 0.66 0.36 Cw =0.54 BASIN SDI-16B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 6170.27 0.14 0.73 0.10 Dense Residential 23132.04 0.53 0.50 0.27 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Totals 29302.3 0.67 0.37 Cw =0.55 BASIN SDI-17B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 5651.14 0.13 0.73 0.09 Dense Residential 551.25 0.01 0.50 0.01 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 6202.4 0.14 0.10 Cw =0.71 BASIN SDI-18B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 1645.83 0.04 0.73 0.03 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 1645.8 0.04 0.03 Cw =0.73 BASIN SDI-19B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 21007 0.48 0.73 0.35 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 21007.0 0.48 0.35 Cw =0.73 BASIN SDI-20B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 22468.84 0.52 0.73 0.38 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 22468.8 0.52 0.38 Cw =0.73 BASIN SDI-21B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 5821.34 0.13 0.73 0.10 Dense Residential 84105.66 1.93 0.50 0.97 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Totals 89927.0 2.06 1.06 Cw =0.51 BASIN SDI-22B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14154.89 0.32 0.73 0.24 Dense Residential 28637.7 0.66 0.50 0.33 Commercial 0 0.00 0.60 0.00 Open Land 2500.87 0.06 0.20 0.01 Totals 45293.5 1.04 0.58 Cw =0.56 BASIN SDI-23B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 18199.36 0.42 0.73 0.30 Dense Residential 44726.69 1.03 0.50 0.51 Commercial 0 0.00 0.60 0.00 Open Land 4109.71 0.09 0.20 0.02 Totals 67035.8 1.54 0.84 Cw =0.54 BASIN SDI-24B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 16909.71 0.39 0.73 0.28 Dense Residential 45663.25 1.05 0.50 0.52 Commercial 0 0.00 0.60 0.00 Open Land 5947.15 0.14 0.20 0.03 Totals 68520.1 1.57 0.83 Cw =0.53 BASIN SDI-25B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 36356.56 0.83 0.73 0.61 Dense Residential 54905.57 1.26 0.50 0.63 Commercial 0 0.00 0.60 0.00 Open Land 7161.3 0.16 0.20 0.03 Totals 98423.4 2.26 1.27 Cw =0.56 BASIN SDI-26B Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 6240.0 0.14 0.73 0.10 Dense Residential 81418.08 1.87 0.50 0.93 Commercial 0 0.00 0.60 0.00 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Open Land 0 0.00 0.20 0.00 Totals 87658.1 2.01 1.04 Cw =0.52 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Equations Used: Qp = C i A (Modified Rational Method) i = a * (DURATION) ^ -(b) (City of Bozeman) Overland Flow tc=((1.8)*(1.1-C)*(D^(1/2)))/(S^(1/3)) (City of Bozeman) Gutter Flow V=3.28*k*(S^(1/2), where k=0.618 (paved) (FHWA HEC 22, Eqn 3-4) BASIN 4B Basin Area (ac): 1.17 Storm Event Intensity Post-Dev C (weighted): 0.40 (yr) (in/hr)A B Overland Distance (ft): 70 2 0.83 0.36 0.6 Overland Slope (%): 1.0 5 1.26 0.52 0.64 Gutter Flow Distance (ft): 391.0 10 1.57 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.89 0.78 0.64 Post-Dev. Tc (min): 15.0 50 2.30 0.92 0.66 Post-Dev. Tc (hr.): 0.25 100 2.56 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.40 0.40 0.40 0.40 Storm Intensity (in/hr): 0.83 1.57 1.89 2.56 Post-Dev Qp (cfs):0.39 0.75 0.90 1.21 BASIN 5B Basin Area (ac): 1.97 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 391.5 2 0.65 0.36 0.6 Overland Slope (%): 1.0 5 0.98 0.52 0.64 Gutter Flow Distance (ft): 171.0 10 1.22 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.47 0.78 0.64 Post-Dev. Tc (min): 22.3 50 1.77 0.92 0.66 Post-Dev. Tc (hr.): 0.37 100 1.96 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.65 1.22 1.47 1.96 Post-Dev Qp (cfs):0.68 1.27 1.53 2.05 BASIN 6B Basin Area (ac): 1.30 Storm Event Intensity Post-Dev C (weighted): 0.32 (yr) (in/hr)A B Overland Distance (ft): 225 2 0.63 0.36 0.6 Overland Slope (%): 1.0 5 0.94 0.52 0.64 Gutter Flow Distance (ft): 243.0 10 1.17 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.41 0.78 0.64 Post-Dev. Tc (min): 23.8 50 1.69 0.92 0.66 Post-Dev. Tc (hr.): 0.40 100 1.88 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.32 0.32 0.32 0.32 Storm Intensity (in/hr): 0.63 1.17 1.41 1.88 Post-Dev Qp (cfs):0.26 0.49 0.59 0.79 URBAN + FARM PHASE 2 - BASIN B MAJOR SUBDIVISION POST-DEVELOPMENT SUB BASIN FLOWS Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 7B Basin Area (ac): 1.35 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 503 2 0.61 0.36 0.6 Overland Slope (%): 1.0 5 0.91 0.52 0.64 Gutter Flow Distance (ft): 197.0 10 1.13 0.64 0.65 Gutter Flow Slope (%): 0.7 25 1.37 0.78 0.64 Post-Dev. Tc (min): 25.0 50 1.64 0.92 0.66 Post-Dev. Tc (hr.): 0.42 100 1.82 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.61 1.13 1.37 1.82 Post-Dev Qp (cfs):0.44 0.81 0.98 1.30 BASIN 8B Basin Area (ac): 2.08 Storm Event Intensity Post-Dev C (weighted): 0.52 (yr) (in/hr)A B Overland Distance (ft): 406 2 0.64 0.36 0.6 Overland Slope (%): 1.0 5 0.97 0.52 0.64 Gutter Flow Distance (ft): 176.0 10 1.20 0.64 0.65 Gutter Flow Slope (%): 0.64 25 1.45 0.78 0.64 Post-Dev. Tc (min): 22.8 50 1.74 0.92 0.66 Post-Dev. Tc (hr.): 0.38 100 1.93 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.52 0.52 0.52 0.52 Storm Intensity (in/hr): 0.64 1.20 1.45 1.93 Post-Dev Qp (cfs):0.70 1.30 1.57 2.09 BASIN 9B Basin Area (ac): 1.69 Storm Event Intensity Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 23 2 0.96 0.36 0.6 Overland Slope (%): 1.0 5 1.49 0.52 0.64 Gutter Flow Distance (ft): 610.0 10 1.86 0.64 0.65 Gutter Flow Slope (%): 0.6 25 2.23 0.78 0.64 Post-Dev. Tc (min): 11.6 50 2.72 0.92 0.66 Post-Dev. Tc (hr.): 0.19 100 3.04 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.96 1.86 2.23 3.04 Post-Dev Qp (cfs):0.88 1.69 2.03 2.76 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 10B Basin Area (ac): 0.69 Storm Event Intensity Post-Dev C (weighted): 0.56 (yr) (in/hr)A B Overland Distance (ft): 165 2 0.89 0.36 0.6 Overland Slope (%): 1.0 5 1.37 0.52 0.64 Gutter Flow Distance (ft): 129.5 10 1.71 0.64 0.65 Gutter Flow Slope (%): 1.8 25 2.06 0.78 0.64 Post-Dev. Tc (min): 13.2 50 2.50 0.92 0.66 Post-Dev. Tc (hr.): 0.22 100 2.79 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.56 0.56 0.56 0.56 Storm Intensity (in/hr): 0.89 1.71 2.06 2.79 Post-Dev Qp (cfs):0.35 0.67 0.81 1.09 BASIN 11B Basin Area (ac): 0.75 Storm Event Intensity Post-Dev C (weighted): 0.61 (yr) (in/hr)A B Overland Distance (ft): 46 2 1.16 0.36 0.6 Overland Slope (%): 1.0 5 1.81 0.52 0.64 Gutter Flow Distance (ft): 335.0 10 2.27 0.64 0.65 Gutter Flow Slope (%): 1.2 25 2.72 0.78 0.64 Post-Dev. Tc (min): 8.5 50 3.33 0.92 0.66 Post-Dev. Tc (hr.): 0.14 100 3.73 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.61 0.61 0.61 0.61 Storm Intensity (in/hr): 1.16 2.27 2.72 3.73 Post-Dev Qp (cfs):0.53 1.03 1.23 1.69 BASIN 12B Basin Area (ac): 0.30 Storm Event Intensity Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 13.5 2 1.36 0.36 0.6 Overland Slope (%): 1.0 5 2.15 0.52 0.64 Gutter Flow Distance (ft): 430.0 10 2.71 0.64 0.65 Gutter Flow Slope (%): 0.75 25 3.23 0.78 0.64 Post-Dev. Tc (min): 6.5 50 3.98 0.92 0.66 Post-Dev. Tc (hr.): 0.11 100 4.46 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.36 2.71 3.23 4.46 Post-Dev Qp (cfs):0.30 0.59 0.71 0.98 BASIN 13B Basin Area (ac): 1.10 Storm Event Intensity Post-Dev C (weighted): 0.39 (yr) (in/hr)A B Overland Distance (ft): 79 2 0.83 0.36 0.6 Overland Slope (%): 1.0 5 1.27 0.52 0.64 Gutter Flow Distance (ft): 370.0 10 1.58 0.64 0.65 Gutter Flow Slope (%): 0.75 25 1.90 0.78 0.64 Post-Dev. Tc (min): 14.9 50 2.31 0.92 0.66 Post-Dev. Tc (hr.): 0.25 100 2.57 1.01 0.67 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.39 0.39 0.39 0.39 Storm Intensity (in/hr): 0.83 1.58 1.90 2.57 Post-Dev Qp (cfs):0.35 0.67 0.81 1.09 BASIN 14B Basin Area (ac): 1.33 Storm Event Intensity Post-Dev C (weighted): 0.57 (yr) (in/hr)A B Overland Distance (ft): 293.5 2 0.74 0.36 0.6 Overland Slope (%): 1.0 5 1.12 0.52 0.64 Gutter Flow Distance (ft): 142.0 10 1.40 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.68 0.78 0.64 Post-Dev. Tc (min): 18.1 50 2.03 0.92 0.66 Post-Dev. Tc (hr.): 0.30 100 2.26 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.57 0.57 0.57 0.57 Storm Intensity (in/hr): 0.74 1.40 1.68 2.26 Post-Dev Qp (cfs):0.56 1.06 1.27 1.71 BASIN 15B Basin Area (ac): 0.66 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 168 2 0.83 0.36 0.6 Overland Slope (%): 1.0 5 1.27 0.52 0.64 Gutter Flow Distance (ft): 143.0 10 1.59 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.91 0.78 0.64 Post-Dev. Tc (min): 14.8 50 2.32 0.92 0.66 Post-Dev. Tc (hr.): 0.25 100 2.58 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.83 1.59 1.91 2.58 Post-Dev Qp (cfs):0.30 0.57 0.68 0.92 BASIN 16B Basin Area (ac): 0.67 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.55 (yr) (in/hr)A B Overland Distance (ft): 171.5 2 0.88 0.36 0.6 Overland Slope (%): 1.0 5 1.35 0.52 0.64 Gutter Flow Distance (ft): 115.0 10 1.68 0.64 0.65 Gutter Flow Slope (%): 2.6 25 2.02 0.78 0.64 Post-Dev. Tc (min): 13.6 50 2.45 0.92 0.66 Post-Dev. Tc (hr.): 0.23 100 2.73 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.55 0.55 0.55 0.55 Storm Intensity (in/hr): 0.88 1.68 2.02 2.73 Post-Dev Qp (cfs):0.32 0.62 0.74 1.01 BASIN 17B Basin Area (ac): 0.14 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.71 (yr) (in/hr)A B Overland Distance (ft): 37 2 1.61 0.36 0.6 Overland Slope (%): 1.0 5 2.57 0.52 0.64 Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Gutter Flow Distance (ft): 133 10 3.24 0.64 0.65 Gutter Flow Slope (%): 2.6 25 3.85 0.78 0.64 Post-Dev. Tc (min): 5.0 50 4.77 0.92 0.66 Post-Dev. Tc (hr.): 0.08 100 5.37 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.71 0.71 0.71 0.71 Storm Intensity (in/hr): 1.61 3.24 3.85 5.37 Post-Dev Qp (cfs):0.16 0.33 0.39 0.54 BASIN 18B Basin Area (ac): 0.04 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 18 2 2.20 0.36 0.6 Overland Slope (%): 1.0 5 3.58 0.52 0.64 Gutter Flow Distance (ft): 20 10 4.54 0.64 0.65 Gutter Flow Slope (%): 2.0 25 5.37 0.78 0.64 Post-Dev. Tc (min): 2.9 50 6.73 0.92 0.66 Post-Dev. Tc (hr.): 0.05 100 7.62 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 2.20 4.54 5.37 7.62 Post-Dev Qp (cfs):0.06 0.13 0.15 0.21 BASIN 19B Basin Area (ac): 0.48 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 43.5 2 1.31 0.36 0.6 Overland Slope (%): 1.0 5 2.05 0.52 0.64 Gutter Flow Distance (ft): 434 10 2.58 0.64 0.65 Gutter Flow Slope (%): 1.9 25 3.08 0.78 0.64 Post-Dev. Tc (min): 7.0 50 3.79 0.92 0.66 Post-Dev. Tc (hr.): 0.12 100 4.26 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.31 2.58 3.08 4.26 Post-Dev Qp (cfs):0.46 0.91 1.08 1.50 BASIN 20B Basin Area (ac): 0.52 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 75 2 1.17 0.36 0.6 Overland Slope (%): 1.0 5 1.83 0.52 0.64 Gutter Flow Distance (ft): 430 10 2.30 0.64 0.65 Gutter Flow Slope (%): 1.9 25 2.75 0.78 0.64 Post-Dev. Tc (min): 8.4 50 3.38 0.92 0.66 Post-Dev. Tc (hr.): 0.14 100 3.78 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.17 2.30 2.75 3.78 Post-Dev Qp (cfs):0.44 0.87 1.04 1.42 BASIN 21B L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Basin Area (ac): 2.06 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.51 (yr) (in/hr)A B Overland Distance (ft): 406 2 0.64 0.36 0.6 Overland Slope (%): 1.0 5 0.96 0.52 0.64 Gutter Flow Distance (ft): 180 10 1.19 0.64 0.65 Gutter Flow Slope (%): 0.64 25 1.44 0.78 0.64 Post-Dev. Tc (min): 23.1 50 1.73 0.92 0.66 Post-Dev. Tc (hr.): 0.38 100 1.92 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.51 0.51 0.51 0.51 Storm Intensity (in/hr): 0.64 1.19 1.44 1.92 Post-Dev Qp (cfs):0.68 1.27 1.53 2.04 BASIN 22B Basin Area (ac): 1.04 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.56 (yr) (in/hr)A B Overland Distance (ft): 391.5 2 0.70 0.36 0.6 Overland Slope (%): 1.0 5 1.05 0.52 0.64 Gutter Flow Distance (ft): 46.5 10 1.31 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.58 0.78 0.64 Post-Dev. Tc (min): 19.9 50 1.90 0.92 0.66 Post-Dev. Tc (hr.): 0.33 100 2.11 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.56 0.56 0.56 0.56 Storm Intensity (in/hr): 0.70 1.31 1.58 2.11 Post-Dev Qp (cfs):0.40 0.76 0.91 1.22 BASIN 23B Basin Area (ac): 1.54 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.54 (yr) (in/hr)A B Overland Distance (ft): 391.5 2 0.67 0.36 0.6 Overland Slope (%): 1.0 5 1.01 0.52 0.64 Gutter Flow Distance (ft): 113.0 10 1.26 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.52 0.78 0.64 Post-Dev. Tc (min): 21.1 50 1.83 0.92 0.66 Post-Dev. Tc (hr.): 0.35 100 2.03 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.54 0.54 0.54 0.54 Storm Intensity (in/hr): 0.67 1.26 1.52 2.03 Post-Dev Qp (cfs):0.56 1.06 1.27 1.70 BASIN 24B Basin Area (ac): 1.57 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 390.5 2 0.66 0.36 0.6 Overland Slope (%): 1.0 5 1.00 0.52 0.64 Gutter Flow Distance (ft): 129.0 10 1.24 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.49 0.78 0.64 Post-Dev. Tc (min): 21.7 50 1.80 0.92 0.66 Post-Dev. Tc (hr.): 0.36 100 1.99 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.66 1.24 1.49 1.99 Post-Dev Qp (cfs):0.55 1.03 1.25 1.66 BASIN 25B Basin Area (ac): 2.26 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.56 (yr) (in/hr)A B Overland Distance (ft): 103 2 0.88 0.36 0.6 Overland Slope (%): 1.0 5 1.34 0.52 0.64 Gutter Flow Distance (ft): 521.0 10 1.68 0.64 0.65 Gutter Flow Slope (%): 1.25 25 2.01 0.78 0.64 Post-Dev. Tc (min): 13.6 50 2.45 0.92 0.66 Post-Dev. Tc (hr.): 0.23 100 2.73 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.56 0.56 0.56 0.56 Storm Intensity (in/hr): 0.88 1.68 2.01 2.73 Post-Dev Qp (cfs):1.11 2.13 2.56 3.47 BASIN 26B Basin Area (ac): 2.01 Storm Event Intensity Storm Coeff. (i) Post-Dev C (weighted): 0.52 (yr) (in/hr)A B Overland Distance (ft): 406 2 0.64 0.36 0.6 Overland Slope (%): 1.0 5 0.96 0.52 0.64 Gutter Flow Distance (ft): 172.5 10 1.20 0.64 0.65 Gutter Flow Slope (%): 0.64 25 1.44 0.78 0.64 Post-Dev. Tc (min): 22.9 50 1.74 0.92 0.66 Post-Dev. Tc (hr.): 0.38 100 1.92 1.01 0.67 Storm Event (yr):2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.52 0.52 0.52 0.52 Storm Intensity (in/hr): 0.64 1.20 1.44 1.92 Post-Dev Qp (cfs):0.67 1.24 1.50 2.00 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls 0.90 0.50 0.60 0.20 Note: Coefficients obtained from CoB Design Standards Table I-1 BASIN SDI-1C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 33525.86 0.77 0.73 0.56 Dense Residential 0 0.00 0.50 0.00 Commercial 40327.13 0.93 0.60 0.56 Open Land 5974.31 0.14 0.20 0.03 Totals 79827.3 1.83 1.14 Cw =0.62 BASIN SDI-2C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 11049.91 0.25 0.73 0.19 Dense Residential 89958.25 2.07 0.50 1.03 Commercial 40000.459 0.92 0.60 0.55 Open Land 17785.88 0.41 0.20 0.08 Totals 158794.5 3.65 1.85 Cw =0.51 BASIN SDI-3C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 2020.37 0.05 0.73 0.03 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 2020.4 0.05 0.03 Cw =0.73 URBAN + FARM PHASE 2 - BASIN C MAJOR SUBDIVISION Weighted Runoff Coefficients Asphalt/Concrete Dense Residential Commercial Neighborhood Open Land L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-5C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 27813.14 0.64 0.73 0.47 Dense Residential 34864.257 0.80 0.50 0.40 Commercial 0 0.00 0.60 0.00 Open Land 26444.112 0.61 0.20 0.12 Totals 89121.5 2.05 0.99 Cw =0.48 BASIN SDI-6C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 9596.53 0.22 0.73 0.16 Dense Residential 0 0.00 0.50 0.00 Commercial 36275.03 0.83 0.60 0.50 Open Land 29766.58 0.68 0.20 0.14 Totals 75638.14 1.74 0.80 Cw =0.46 BASIN SDI-7C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 16256.27 0.37 0.73 0.27 Dense Residential 107565.7 2.47 0.50 1.23 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 123822.0 2.84 1.51 Cw =0.53 BASIN SDI-8C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14223.06 0.33 0.73 0.24 Dense Residential 45236.86 1.04 0.50 0.52 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 59459.9 1.37 0.76 Cw =0.56 BASIN SDI-9C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 5655.42 0.13 0.73 0.09 Dense Residential 2180.63 0.05 0.50 0.03 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 7836.1 0.18 0.12 Cw =0.67 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-10C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 8620.47 0.20 0.73 0.14 Dense Residential 10021.07 0.23 0.50 0.12 Commercial 60673.38 1.39 0.60 0.84 Open Land 28720.51 0.66 0.20 0.13 Totals 108035.4 2.48 1.23 Cw =0.49 BASIN SDI-11C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 46042.93 1.06 0.73 0.77 Dense Residential 107213.41 2.46 0.50 1.23 Commercial 0 0.00 0.60 0.00 Open Land 24547.86 0.56 0.20 0.11 Totals 177804.2 4.08 2.11 Cw =0.52 BASIN SDI-12C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 14477.61 0.33 0.73 0.24 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 0 0.00 0.20 0.00 Totals 14477.6 0.33 0.24 Cw =0.73 BASIN SDI-13C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 18245.98 0.42 0.73 0.31 Dense Residential 0 0.00 0.50 0.00 Commercial 28704.23 0.66 0.60 0.40 Open Land 4038.67 0.09 0.20 0.02 Totals 50988.9 1.17 0.72 Cw =0.61 BASIN SDI-14C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 8246 0.19 0.73 0.14 Dense Residential 0 0.00 0.50 0.00 Commercial 20140 0.46 0.60 0.28 Open Land 5422 0.12 0.20 0.02 Totals 33808.0 0.78 0.44 Cw =0.57 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN SDI-15C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 7922 0.18 0.73 0.13 Dense Residential 0 0.00 0.50 0.00 Commercial 0 0.00 0.60 0.00 Open Land 42927 0.99 0.20 0.20 Totals 50849.0 1.17 0.33 Cw =0.28 BASIN SDI-16C Post-Development Weighted C-Value (Cw) Area Area Runoff (sqft) (Acres) Coefficient Calculations R.O.W. 9731 0.22 0.73 0.16 Dense Residential 0 0.00 0.50 0.00 Commercial 15378 0.35 0.60 0.21 Open Land 24144 0.55 0.20 0.11 Totals 49253.0 1.13 0.49 Cw =0.43 L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Equations Used: Qp = C i A (Modified Rational Method) i = a * (DURATION) ^ -(b) (City of Bozeman) Overland Flow tc=((1.8)*(1.1-C)*(D^(1/2)))/(S^(1/3)) (City of Bozeman) Gutter Flow V=3.28*k*(S^(1/2), where k=0.618 (paved) (FHWA HEC 22, Eqn 3-4) BASIN 1C Basin Area (ac): 1.83 Storm Event Intensity Post-Dev C (weighted): 0.62 (yr) (in/hr)A B Overland Distance (ft): 397 2 0.73 0.36 0.6 Overland Slope (%): 1.0 5 1.10 0.52 0.64 Gutter Flow Distance (ft): 127.0 10 1.37 0.64 0.65 Gutter Flow Slope (%): 0.5 25 1.65 0.78 0.64 Post-Dev. Tc (min): 18.5 50 2.00 0.92 0.66 Post-Dev. Tc (hr.): 0.31 100 2.22 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.62 0.62 0.62 0.62 Storm Intensity (in/hr): 0.73 1.37 1.65 2.22 Post-Dev Qp (cfs):0.83 1.57 1.89 2.54 BASIN 2C Basin Area (ac): 3.65 Storm Event Intensity Post-Dev C (weighted): 0.51 (yr) (in/hr)A B Overland Distance (ft): 205 2 0.74 0.36 0.6 Overland Slope (%): 1.0 5 1.12 0.52 0.64 Gutter Flow Distance (ft): 249.0 10 1.39 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.68 0.78 0.64 Post-Dev. Tc (min): 18.2 50 2.02 0.92 0.66 Post-Dev. Tc (hr.): 0.30 100 2.25 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.51 0.51 0.51 0.51 Storm Intensity (in/hr): 0.74 1.39 1.68 2.25 Post-Dev Qp (cfs):1.36 2.57 3.10 4.16 BASIN 3C Basin Area (ac): 0.05 Storm Event Intensity Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 31 2 1.88 0.36 0.6 Overland Slope (%): 1.0 5 3.03 0.52 0.64 Gutter Flow Distance (ft): 17.5 10 3.83 0.64 0.65 Gutter Flow Slope (%): 1.60 25 4.54 0.78 0.64 Post-Dev. Tc (min): 3.8 50 5.66 0.92 0.66 Post-Dev. Tc (hr.): 0.06 100 6.39 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.88 3.83 4.54 6.39 Post-Dev Qp (cfs):0.06 0.13 0.15 0.22 BASIN 5C Basin Area (ac): 2.05 Storm Event Intensity Post-Dev C (weighted): 0.48 (yr) (in/hr)A B Overland Distance (ft): 504 2 0.57 0.36 0.6 Overland Slope (%): 1.0 5 0.85 0.52 0.64 Gutter Flow Distance (ft): 234.0 10 1.06 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.28 0.78 0.64 Post-Dev. Tc (min): 27.7 50 1.53 0.92 0.66 Post-Dev. Tc (hr.): 0.46 100 1.70 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.48 0.48 0.48 0.48 Storm Intensity (in/hr): 0.57 1.06 1.28 1.70 Post-Dev Qp (cfs):0.57 1.05 1.26 1.68 BASIN 6C Basin Area (ac): 1.74 Storm Event Intensity Post-Dev C (weighted): 0.46 (yr) (in/hr)A B Overland Distance (ft): 278 2 0.66 0.36 0.6 URBAN + FARM PHASE 2 - BASIN C MAJOR SUBDIVISION POST-DEVELOPMENT SUB BASIN FLOWS Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Overland Slope (%): 1.0 5 1.00 0.52 0.64 Gutter Flow Distance (ft): 217.0 10 1.24 0.64 0.65 Gutter Flow Slope (%): 0.55 25 1.50 0.78 0.64 Post-Dev. Tc (min): 21.6 50 1.80 0.92 0.66 Post-Dev. Tc (hr.): 0.36 100 2.00 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.46 0.46 0.46 0.46 Storm Intensity (in/hr): 0.66 1.24 1.50 2.00 Post-Dev Qp (cfs):0.53 0.99 1.19 1.59 BASIN 7C Basin Area (ac): 2.84 Storm Event Intensity Post-Dev C (weighted): 0.53 (yr) (in/hr)A B Overland Distance (ft): 458 2 0.63 0.36 0.6 Overland Slope (%): 1.0 5 0.95 0.52 0.64 Gutter Flow Distance (ft): 127.5 10 1.18 0.64 0.65 Gutter Flow Slope (%): 0.55 25 1.43 0.78 0.64 Post-Dev. Tc (min): 23.4 50 1.71 0.92 0.66 Post-Dev. Tc (hr.): 0.39 100 1.90 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.53 0.53 0.53 0.53 Storm Intensity (in/hr): 0.63 1.18 1.43 1.90 Post-Dev Qp (cfs):0.96 1.78 2.15 2.86 BASIN 8C Basin Area (ac): 1.37 Storm Event Intensity Post-Dev C (weighted): 0.56 (yr) (in/hr)A B Overland Distance (ft): 176.5 2 0.79 0.36 0.6 Overland Slope (%): 1.0 5 1.20 0.52 0.64 Gutter Flow Distance (ft): 415.0 10 1.50 0.64 0.65 Gutter Flow Slope (%): 1.12 25 1.80 0.78 0.64 Post-Dev. Tc (min): 16.3 50 2.18 0.92 0.66 Post-Dev. Tc (hr.): 0.27 100 2.42 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.56 0.56 0.56 0.56 Storm Intensity (in/hr): 0.79 1.50 1.80 2.42 Post-Dev Qp (cfs):0.60 1.13 1.36 1.84 Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 9C Basin Area (ac): 0.18 Storm Event Intensity Post-Dev C (weighted): 0.67 (yr) (in/hr)A B Overland Distance (ft): 18 2 1.73 0.36 0.6 Overland Slope (%): 1.0 5 2.77 0.52 0.64 Gutter Flow Distance (ft): 171.0 10 3.50 0.64 0.65 Gutter Flow Slope (%): 1.72 25 4.16 0.78 0.64 Post-Dev. Tc (min): 4.4 50 5.17 0.92 0.66 Post-Dev. Tc (hr.): 0.07 100 5.83 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.67 0.67 0.67 0.67 Storm Intensity (in/hr): 1.73 3.50 4.16 5.83 Post-Dev Qp (cfs):0.21 0.42 0.50 0.70 BASIN 10C Basin Area (ac): 2.48 Storm Event Intensity Post-Dev C (weighted): 0.49 (yr) (in/hr)A B Overland Distance (ft): 379 2 0.65 0.36 0.6 Overland Slope (%): 1.0 5 0.97 0.52 0.64 Gutter Flow Distance (ft): 127.5 10 1.21 0.64 0.65 Gutter Flow Slope (%): 0.55 25 1.46 0.78 0.64 Post-Dev. Tc (min): 22.6 50 1.75 0.92 0.66 Post-Dev. Tc (hr.): 0.38 100 1.94 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.49 0.49 0.49 0.49 Storm Intensity (in/hr): 0.65 1.21 1.46 1.94 Post-Dev Qp (cfs):0.79 1.48 1.79 2.38 BASIN 11C Basin Area (ac): 4.08 Storm Event Intensity Post-Dev C (weighted): 0.52 (yr) (in/hr)A B Overland Distance (ft): 367 2 0.69 0.36 0.6 Overland Slope (%): 1.0 5 1.03 0.52 0.64 Gutter Flow Distance (ft): 72.0 10 1.29 0.64 0.65 Gutter Flow Slope (%): 1.72 25 1.55 0.78 0.64 Post-Dev. Tc (min): 20.5 50 1.87 0.92 0.66 Post-Dev. Tc (hr.): 0.34 100 2.07 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.52 0.52 0.52 0.52 Storm Intensity (in/hr): 0.69 1.29 1.55 2.07 Post-Dev Qp (cfs):1.45 2.72 3.28 4.38 BASIN 12C Basin Area (ac): 0.33 Storm Event Intensity Post-Dev C (weighted): 0.73 (yr) (in/hr)A B Overland Distance (ft): 71.5 2 1.25 0.36 0.6 Overland Slope (%): 1.0 5 1.97 0.52 0.64 Gutter Flow Distance (ft): 297.0 10 2.47 0.64 0.65 Gutter Flow Slope (%): 1.72 25 2.95 0.78 0.64 Post-Dev. Tc (min): 7.5 50 3.63 0.92 0.66 Post-Dev. Tc (hr.): 0.12 100 4.07 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.73 0.73 0.73 0.73 Storm Intensity (in/hr): 1.25 2.47 2.95 4.07 Post-Dev Qp (cfs):0.30 0.60 0.72 0.99 BASIN 13C Basin Area (ac): 1.17 Storm Event Intensity Post-Dev C (weighted): 0.61 (yr) (in/hr)A B Overland Distance (ft): 398 2 0.73 0.36 0.6 Overland Slope (%): 1.0 5 1.11 0.52 0.64 Gutter Flow Distance (ft): 74.0 10 1.39 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.67 0.78 0.64 Post-Dev. Tc (min): 18.3 50 2.02 0.92 0.66 Post-Dev. Tc (hr.): 0.30 100 2.24 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.61 0.61 0.61 0.61 Storm Intensity (in/hr): 0.73 1.39 1.67 2.24 Post-Dev Qp (cfs):0.53 1.00 1.20 1.61 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls BASIN 14C Basin Area (ac): 0.78 Storm Event Intensity Post-Dev C (weighted): 0.57 (yr) (in/hr)A B Overland Distance (ft): 311 2 0.77 0.36 0.6 Overland Slope (%): 1.0 5 1.16 0.52 0.64 Gutter Flow Distance (ft): 15.0 10 1.45 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.74 0.78 0.64 Post-Dev. Tc (min): 17.1 50 2.11 0.92 0.66 Post-Dev. Tc (hr.): 0.28 100 2.34 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.57 0.57 0.57 0.57 Storm Intensity (in/hr): 0.77 1.45 1.74 2.34 Post-Dev Qp (cfs):0.34 0.64 0.77 1.03 BASIN 15C Basin Area (ac): 1.17 Storm Event Intensity Post-Dev C (weighted): 0.28 (yr) (in/hr)A B Overland Distance (ft): 325 2 0.59 0.36 0.6 Overland Slope (%): 1.0 5 0.87 0.52 0.64 Gutter Flow Distance (ft): 15.0 10 1.08 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.31 0.78 0.64 Post-Dev. Tc (min): 26.7 50 1.57 0.92 0.66 Post-Dev. Tc (hr.): 0.44 100 1.74 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.28 0.28 0.28 0.28 Storm Intensity (in/hr): 0.59 1.08 1.31 1.74 Post-Dev Qp (cfs):0.19 0.36 0.43 0.57 BASIN 16C Basin Area (ac): 1.13 Storm Event Intensity Post-Dev C (weighted): 0.43 (yr) (in/hr)A B Overland Distance (ft): 390 2 0.62 0.36 0.6 Overland Slope (%): 1.0 5 0.93 0.52 0.64 Gutter Flow Distance (ft): 15.0 10 1.16 0.64 0.65 Gutter Flow Slope (%): 0.50 25 1.40 0.78 0.64 Post-Dev. Tc (min): 24.0 50 1.68 0.92 0.66 Post-Dev. Tc (hr.): 0.40 100 1.87 1.01 0.67 Storm Event (yr): 2 10 25 100 Storm Coeff. A: 0.36 0.64 0.78 1.01 Storm Coeff. B:0.60 0.65 0.64 0.67 Composite C: 0.43 0.43 0.43 0.43 Storm Intensity (in/hr): 0.62 1.16 1.40 1.87 Post-Dev Qp (cfs):0.30 0.56 0.68 0.91 Storm Coeff. (i) Storm Coeff. (i) Storm Coeff. (i) L:\203430\Computations\PHASE 2\Stormwater\Stormwater Calculations Inlet Calcs.xls Project Description UF_Phase 2 New.SPF Project Options CFS Elevation Rational User-Defined Hydrodynamic YES NO Analysis Options 00:00:00 0:00:00 00:00:00 0:00:00 00:00:00 0:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 30 seconds Number of Elements Qty 0 55 88 12 17 0 59 0 111 39 72 0 0 0 0 0 0 Rainfall Details 25 year(s) End Analysis On ......................................................................... File Name .................................................................................. UF_Phase 2 New.SPF Description ................................................................................ Flow Units ................................................................................. Elevation Type ........................................................................... Hydrology Method ..................................................................... Time of Concentration (TOC) Method ........................................ Link Routing Method ................................................................. Enable Overflow Ponding at Nodes ............................................ Skip Steady State Analysis Time Periods ..................................... Start Analysis On ........................................................................ Flow Diversions .................................................................. Start Reporting On ..................................................................... Antecedent Dry Days ................................................................. Runoff (Dry Weather) Time Step ................................................ Runoff (Wet Weather) Time Step ............................................... Reporting Time Step .................................................................. Routing Time Step ..................................................................... Rain Gages ................................................................................. Subbasins................................................................................... Nodes......................................................................................... Junctions ........................................................................... Outfalls .............................................................................. Return Period............................................................................. Inlets ................................................................................. Storage Nodes ................................................................... Links........................................................................................... Channels ............................................................................ Pipes .................................................................................. Pumps ............................................................................... Orifices .............................................................................. Weirs ................................................................................. Outlets ............................................................................... Pollutants .................................................................................. Land Uses .................................................................................. Inlet Summary SN Element Inlet Manufacturer Inlet Number of Catchbasin Max (Rim)Initial Ponded Peak Peak Flow Peak Flow Inlet Allowable Max Gutter Max Gutter ID Manufacturer Part Location Inlets Invert Elevation Water Area Flow Intercepted Bypassing Efficiency Spread Spread Water Elev. Number Elevation Elevation by Inlet during Peak during Peak during Peak Inlet Flow Flow Flow (ft)(ft)(ft)(ft²)(cfs)(cfs)(cfs)(%)(ft)(ft)(ft) 1 MH-3C FHWA HEC-22 GENERIC N/A On Grade 1 4819.75 4823.39 4819.75 N/A 1.28 1.08 0.19 84.73 7.00 5.35 4823.60 2 SDI-10A FHWA HEC-22 GENERIC N/A On Grade 1 4811.50 9627.29 4811.50 N/A 3.02 2.20 0.82 72.83 7.00 6.74 9627.54 3 SDI-10C FHWA HEC-22 GENERIC N/A On Grade 1 4818.60 4821.60 4818.60 N/A 1.02 0.88 0.14 86.19 7.00 5.60 4821.81 4 SDI-11A FHWA HEC-22 GENERIC N/A On Grade 1 4811.30 9627.29 4811.30 N/A 1.93 1.56 0.37 80.81 7.00 5.59 9627.51 5 SDI-11C FHWA HEC-22 GENERIC N/A On Grade 1 4827.83 4830.36 4827.83 N/A 2.56 1.90 0.66 74.17 7.00 6.76 4830.61 6 SDI-12A FHWA HEC-22 GENERIC N/A On Grade 1 4822.00 4824.99 4822.00 N/A 1.93 1.48 0.45 76.80 7.00 7.30 4825.26 7 SDI-12B FHWA HEC-22 GENERIC N/A On Grade 1 4818.10 4821.79 4818.10 N/A 0.70 0.65 0.05 92.97 7.00 4.08 4821.96 8 SDI-12C FHWA HEC-22 GENERIC N/A On Grade 1 4827.63 4830.36 4827.63 N/A 0.70 0.66 0.04 93.77 7.00 3.89 4830.52 9 SDI-13A FHWA HEC-22 GENERIC N/A On Grade 1 4817.90 4822.87 4817.90 N/A 0.71 0.66 0.04 93.76 7.00 3.88 4823.03 10 SDI-13B FHWA HEC-22 GENERIC N/A On Grade 1 4818.55 4821.79 4817.90 N/A 0.82 0.74 0.07 91.07 7.00 4.39 4821.97 11 SDI-13C FHWA HEC-22 GENERIC N/A On Grade 1 4826.00 4828.75 4826.00 N/A 1.19 1.00 0.19 84.05 7.00 5.99 4828.98 12 SDI-14A FHWA HEC-22 GENERIC N/A On Grade 1 4811.50 4813.98 4811.50 N/A 1.46 1.25 0.20 86.01 7.00 4.86 4814.17 13 SDI-14B FHWA HEC-22 GENERIC N/A On Sag 1 4818.70 4820.87 4817.90 10.00 1.27 N/A N/A N/A 7.00 5.60 4821.04 14 SDI-14C FHWA HEC-22 GENERIC N/A On Grade 1 4821.30 4824.93 4821.30 N/A 1.56 1.27 0.29 81.62 7.00 5.80 4825.15 15 SDI-15A FHWA HEC-22 GENERIC N/A On Sag 1 4813.25 4817.11 4813.50 10.00 0.34 N/A N/A N/A 7.00 3.33 4817.26 16 SDI-15B FHWA HEC-22 GENERIC N/A On Sag 1 4817.57 4820.87 4817.57 10.00 0.68 N/A N/A N/A 7.00 3.85 4820.99 17 SDI-15C FHWA HEC-22 GENERIC N/A On Grade 1 4822.05 4824.27 4822.05 N/A 0.87 0.77 0.10 87.98 7.00 5.14 4824.44 18 SDI-16A FHWA HEC-22 GENERIC N/A On Grade 1 4818.20 4823.67 4818.20 N/A 2.35 1.73 0.62 73.69 7.00 7.88 4823.95 19 SDI-17A FHWA HEC-22 GENERIC N/A On Grade 1 4819.50 4822.21 4819.50 N/A 2.80 1.99 0.82 70.82 7.00 8.46 4822.51 20 SDI-18B FHWA HEC-22 GENERIC N/A On Grade 1 4817.90 4821.06 4817.30 N/A 0.30 0.29 0.00 98.67 7.00 3.00 4821.20 21 SDI-19B FHWA HEC-22 GENERIC N/A On Sag 1 4815.15 4816.59 4815.15 10.00 1.07 N/A N/A N/A 7.00 5.03 4816.74 22 SDI-1A FHWA HEC-22 GENERIC N/A On Grade 1 4816.40 4819.75 4816.40 N/A 0.74 0.68 0.05 93.03 7.00 4.02 4819.92 23 SDI-1C1 FHWA HEC-22 GENERIC N/A On Sag 1 4824.75 4827.74 4824.75 10.00 0.00 N/A N/A N/A 7.00 4.81 4827.89 24 SDI-1C2 FHWA HEC-22 GENERIC N/A On Sag 1 4825.00 4827.74 4825.00 10.00 2.06 N/A N/A N/A 7.00 7.55 4827.97 25 SDI-1D FHWA HEC-22 GENERIC N/A On Grade 1 4817.45 4819.82 4817.45 N/A 0.99 0.91 0.08 91.49 7.00 4.12 4819.99 26 SDI-20B FHWA HEC-22 GENERIC N/A On Grade 1 4815.40 4818.71 4815.40 N/A 1.03 0.92 0.10 89.99 7.00 4.39 4818.89 27 SDI-21B FHWA HEC-22 GENERIC N/A On Grade 1 4817.20 4820.10 4816.80 N/A 0.41 0.40 0.01 96.60 7.00 3.56 4820.26 28 SDI-22B FHWA HEC-22 GENERIC N/A On Grade 1 4823.00 4825.54 4823.00 N/A 0.92 0.81 0.11 87.56 7.00 5.37 4825.75 29 SDI-23B FHWA HEC-22 GENERIC N/A On Sag 1 4821.65 4824.39 4821.65 10.00 1.06 N/A N/A N/A 7.00 5.02 4824.54 30 SDI-24B FHWA HEC-22 GENERIC N/A On Grade 1 4821.00 4824.96 4821.00 N/A 1.01 0.87 0.14 86.32 7.00 5.58 4825.17 31 SDI-25B FHWA HEC-22 GENERIC N/A On Grade 1 4822.80 4826.67 4822.80 N/A 1.98 1.51 0.47 76.36 7.00 7.37 4826.94 32 SDI-26B FHWA HEC-22 GENERIC N/A On Grade 1 4816.20 4818.90 4815.80 N/A 0.39 0.38 0.01 97.00 7.00 3.46 4819.05 33 SDI-2A FHWA HEC-22 GENERIC N/A On Grade 1 4812.50 4815.96 4812.75 N/A 1.83 1.50 0.32 82.25 7.00 5.36 4816.17 34 SDI-2C FHWA HEC-22 GENERIC N/A On Sag 1 4825.15 4827.77 4825.15 10.00 1.56 N/A N/A N/A 7.00 6.35 4827.96 35 SDI-2D FHWA HEC-22 GENERIC N/A On Grade 1 4817.37 4819.82 4817.37 N/A 1.50 1.28 0.22 85.51 7.00 4.92 4820.02 36 SDI-3A FHWA HEC-22 GENERIC N/A On Grade 1 4811.05 4813.98 4811.30 N/A 1.87 1.53 0.34 81.90 7.00 5.40 4814.19 37 SDI-3C FHWA HEC-22 GENERIC N/A On Grade 1 4824.15 4827.87 4824.15 N/A 0.28 0.28 0.00 99.93 7.00 2.26 4827.99 38 SDI-4A FHWA HEC-22 GENERIC N/A On Grade 1 4816.60 4819.77 4816.60 N/A 2.66 1.95 0.71 73.24 7.00 6.97 4820.03 39 SDI-4B FHWA HEC-22 GENERIC N/A On Sag 1 4821.80 4824.39 4821.80 10.00 0.88 N/A N/A N/A 7.00 4.50 4824.53 40 SDI-4C FHWA HEC-22 GENERIC N/A On Grade 1 4817.50 4821.56 4817.50 N/A 0.94 0.86 0.09 90.96 7.00 4.26 4821.74 41 SDI-5A1 FHWA HEC-22 GENERIC N/A On Sag 1 4812.40 4815.65 4812.65 10.00 0.31 N/A N/A N/A 7.00 1.96 4815.71 42 SDI-5A2 FHWA HEC-22 GENERIC N/A On Sag 1 4812.65 4815.47 4812.65 10.00 1.41 N/A N/A N/A 7.00 5.98 4815.65 43 SDI-5B FHWA HEC-22 GENERIC N/A On Grade 1 4820.20 4825.57 4820.20 N/A 1.25 1.04 0.21 83.38 7.00 6.10 4825.80 44 SDI-5C FHWA HEC-22 GENERIC N/A On Grade 1 4817.30 4820.38 4817.30 N/A 0.98 0.89 0.09 90.58 7.00 4.30 4820.56 45 SDI-6A FHWA HEC-22 GENERIC N/A On Grade 1 4811.95 4815.67 4812.45 N/A 1.09 0.98 0.11 90.35 7.00 4.27 4815.84 46 SDI-6B FHWA HEC-22 GENERIC N/A On Grade 1 4820.20 4824.96 4819.90 N/A 0.59 0.56 0.03 94.79 7.00 3.78 4825.12 47 SDI-6C1 FHWA HEC-22 GENERIC N/A On Sag 1 4817.20 4820.20 4817.20 10.00 0.07 N/A N/A N/A 7.00 1.36 4820.24 Inlet Summary SN Element Inlet Manufacturer Inlet Number of Catchbasin Max (Rim)Initial Ponded Peak Peak Flow Peak Flow Inlet Allowable Max Gutter Max Gutter ID Manufacturer Part Location Inlets Invert Elevation Water Area Flow Intercepted Bypassing Efficiency Spread Spread Water Elev. Number Elevation Elevation by Inlet during Peak during Peak during Peak Inlet Flow Flow Flow (ft)(ft)(ft)(ft²)(cfs)(cfs)(cfs)(%)(ft)(ft)(ft) 48 SDI-6C2 FHWA HEC-22 GENERIC N/A On Sag 1 4817.20 4820.21 4817.20 10.00 1.16 N/A N/A N/A 7.00 5.30 4820.37 49 SDI-7A1 FHWA HEC-22 GENERIC N/A On Sag 1 4814.20 4817.14 4814.20 10.00 0.35 N/A N/A N/A 7.00 3.37 4817.28 50 SDI-7A2 FHWA HEC-22 GENERIC N/A On Sag 1 4814.20 4817.17 4814.20 10.00 0.73 N/A N/A N/A 7.00 5.30 4817.45 51 SDI-7B FHWA HEC-22 GENERIC N/A On Sag 1 4814.70 4817.67 4814.50 10.00 0.98 N/A N/A N/A 7.00 4.78 4817.81 52 SDI-7C FHWA HEC-22 GENERIC N/A On Grade 1 4817.40 4820.19 4817.40 N/A 2.15 0.35 1.79 16.51 7.00 5.74 4820.41 53 SDI-8A FHWA HEC-22 GENERIC N/A On Grade 1 4814.00 4817.97 4814.25 N/A 1.79 1.44 0.35 80.46 7.00 5.80 4818.19 54 SDI-8B1 FHWA HEC-22 GENERIC N/A On Sag 1 4815.00 4817.72 4814.90 10.00 0.00 N/A N/A N/A 7.00 4.81 4817.87 55 SDI-8B2 FHWA HEC-22 GENERIC N/A On Sag 1 4815.40 4817.72 4814.90 10.00 0.45 N/A N/A N/A 7.00 2.23 4817.79 56 SDI-8C FHWA HEC-22 GENERIC N/A On Grade 1 4814.95 4817.34 4814.95 N/A 1.45 1.25 0.20 86.07 7.00 4.85 4817.53 57 SDI-9A FHWA HEC-22 GENERIC N/A On Grade 1 4814.50 4817.96 4814.50 N/A 1.76 1.42 0.34 80.73 7.00 5.77 4818.19 58 SDI-9B FHWA HEC-22 GENERIC N/A On Sag 1 4815.10 4817.71 4815.10 10.00 1.43 N/A N/A N/A 7.00 5.49 4817.87 59 SDI-9C FHWA HEC-22 GENERIC N/A On Grade 1 4814.30 4817.80 4814.30 N/A 4.84 3.57 1.27 73.77 7.00 5.91 4818.11 Junction Input SN Element Invert Ground/Rim Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum ID Elevation (Max)(Max)Water Water Elevation Depth Area Pipe Elevation Offset Elevation Depth Cover (ft)(ft)(ft)(ft)(ft)(ft)(ft)(ft²)(in) 1 MH-1C 4827.30 4830.02 2.72 4827.30 0.00 4830.02 0.00 0.00 17.59 2 MH-2B 4815.00 4818.84 3.84 4814.80 -0.20 4818.84 0.00 0.00 22.12 3 MH-2C 4824.55 4828.80 4.25 4824.55 0.00 4828.80 0.00 0.00 33.04 4 MH-3B 4813.80 4818.84 5.04 4813.70 -0.10 4818.84 0.00 0.00 36.46 5 MH-4A 4813.55 4817.69 4.14 4813.80 0.25 4817.69 0.00 0.00 28.63 6 MH-4C 4816.75 4821.14 4.39 4816.75 0.00 4821.14 0.00 0.00 34.65 7 MH-5A 4812.25 4818.29 6.04 4812.50 0.25 4818.29 0.00 0.00 51.51 8 MH-5B 4818.10 4821.58 3.48 4817.50 -0.60 4821.58 0.00 0.00 20.82 9 MH-5C 4818.30 4821.85 3.55 4818.30 0.00 4821.85 0.00 0.00 27.56 10 MH-A1 4810.00 4811.44 1.44 4810.00 0.00 4811.44 0.00 0.00 2.25 11 MH-A2 4808.20 4813.25 5.05 4808.20 0.00 4813.25 0.00 0.00 45.60 12 MH-C1 4821.75 4824.99 3.24 4821.75 0.00 4824.99 0.00 0.00 23.93 Junction Results SN Element Peak Peak Max HGL Max HGL Max Min Average HGL Average HGL Time of Time of Total Total Time ID Inflow Lateral Elevation Depth Surcharge Freeboard Elevation Depth Max HGL Peak Flooded Flooded Inflow Attained Attained Depth Attained Attained Attained Occurrence Flooding Volume Attained Occurrence (cfs)(cfs)(ft)(ft)(ft)(ft)(ft)(ft)(days hh:mm)(days hh:mm)(ac-in)(min) 1 MH-1C 1.89 0.00 4827.80 0.50 0.00 2.22 4827.33 0.03 0 00:31 0 00:00 0.00 0.00 2 MH-2B 8.83 0.00 4816.47 1.47 0.00 2.38 4815.07 0.07 0 00:22 0 00:00 0.00 0.00 3 MH-2C 5.88 0.00 4825.59 1.04 0.00 3.21 4824.60 0.05 0 00:20 0 00:00 0.00 0.00 4 MH-3B 9.64 0.00 4815.14 1.34 0.00 3.70 4813.86 0.06 0 00:23 0 00:00 0.00 0.00 5 MH-4A 8.64 0.00 4815.04 1.49 0.00 2.64 4813.61 0.06 0 00:24 0 00:00 0.00 0.00 6 MH-4C 5.11 0.00 4817.44 0.69 0.00 3.70 4816.79 0.04 0 00:21 0 00:00 0.00 0.00 7 MH-5A 8.87 0.00 4813.72 1.47 0.00 4.57 4812.31 0.06 0 00:25 0 00:00 0.00 0.00 8 MH-5B 7.66 0.00 4819.64 1.54 0.00 1.95 4818.16 0.06 0 00:19 0 00:00 0.00 0.00 9 MH-5C 0.88 0.00 4818.67 0.37 0.00 3.18 4818.31 0.01 0 00:20 0 00:00 0.00 0.00 10 MH-A1 0.00 0.00 4810.00 0.00 0.00 1.44 4810.00 0.00 0 00:00 0 00:00 0.00 0.00 11 MH-A2 0.00 0.00 4808.20 0.00 0.00 5.05 4808.20 0.00 0 00:00 0 00:00 0.00 0.00 12 MH-C1 1.95 1.95 4822.15 0.40 0.00 2.85 4821.77 0.02 0 00:40 0 00:00 0.00 0.00 Inlet Input SN Element Inlet Manufacturer Inlet Number of Catchbasin Max (Rim)Inlet Initial Initial Ponded Grate ID Manufacturer Part Location Inlets Invert Elevation Depth Water Water Area Clogging Number Elevation Elevation Depth Factor (ft)(ft)(ft)(ft)(ft)(ft²)(%) 1 MH-3C FHWA HEC-22 GENERIC N/A On Grade 1 4819.75 4823.39 3.64 4819.75 0.00 N/A 0.00 2 SDI-10A FHWA HEC-22 GENERIC N/A On Grade 1 4811.50 9627.29 4815.79 4811.50 0.00 N/A 0.00 3 SDI-10C FHWA HEC-22 GENERIC N/A On Grade 1 4818.60 4821.60 3.00 4818.60 0.00 N/A 0.00 4 SDI-11A FHWA HEC-22 GENERIC N/A On Grade 1 4811.30 9627.29 4815.99 4811.30 0.00 N/A 0.00 5 SDI-11C FHWA HEC-22 GENERIC N/A On Grade 1 4827.83 4830.36 2.53 4827.83 0.00 N/A 0.00 6 SDI-12A FHWA HEC-22 GENERIC N/A On Grade 1 4822.00 4824.99 2.99 4822.00 0.00 N/A 0.00 7 SDI-12B FHWA HEC-22 GENERIC N/A On Grade 1 4818.10 4821.79 3.69 4818.10 0.00 N/A 0.00 8 SDI-12C FHWA HEC-22 GENERIC N/A On Grade 1 4827.63 4830.36 2.73 4827.63 0.00 N/A 0.00 9 SDI-13A FHWA HEC-22 GENERIC N/A On Grade 1 4817.90 4822.87 4.97 4817.90 0.00 N/A 0.00 10 SDI-13B FHWA HEC-22 GENERIC N/A On Grade 1 4818.55 4821.79 3.24 4817.90 -0.65 N/A 0.00 11 SDI-13C FHWA HEC-22 GENERIC N/A On Grade 1 4826.00 4828.75 2.75 4826.00 0.00 N/A 0.00 12 SDI-14A FHWA HEC-22 GENERIC N/A On Grade 1 4811.50 4813.98 2.48 4811.50 0.00 N/A 0.00 13 SDI-14B FHWA HEC-22 GENERIC N/A On Sag 1 4818.70 4820.87 2.17 4817.90 -0.80 10.00 50.00 14 SDI-14C FHWA HEC-22 GENERIC N/A On Grade 1 4821.30 4824.93 3.63 4821.30 0.00 N/A 0.00 15 SDI-15A FHWA HEC-22 GENERIC N/A On Sag 1 4813.25 4817.11 3.86 4813.50 0.25 10.00 0.00 16 SDI-15B FHWA HEC-22 GENERIC N/A On Sag 1 4817.57 4820.87 3.31 4817.57 0.00 10.00 0.00 17 SDI-15C FHWA HEC-22 GENERIC N/A On Grade 1 4822.05 4824.27 2.22 4822.05 0.00 N/A 0.00 18 SDI-16A FHWA HEC-22 GENERIC N/A On Grade 1 4818.20 4823.67 5.47 4818.20 0.00 N/A 0.00 19 SDI-17A FHWA HEC-22 GENERIC N/A On Grade 1 4819.50 4822.21 2.71 4819.50 0.00 N/A 0.00 20 SDI-18B FHWA HEC-22 GENERIC N/A On Grade 1 4817.90 4821.06 3.16 4817.30 -0.60 N/A 0.00 21 SDI-19B FHWA HEC-22 GENERIC N/A On Sag 1 4815.15 4816.59 1.44 4815.15 0.00 10.00 0.00 22 SDI-1A FHWA HEC-22 GENERIC N/A On Grade 1 4816.40 4819.75 3.35 4816.40 0.00 N/A 0.00 23 SDI-1C1 FHWA HEC-22 GENERIC N/A On Sag 1 4824.75 4827.74 2.99 4824.75 0.00 10.00 50.00 24 SDI-1C2 FHWA HEC-22 GENERIC N/A On Sag 1 4825.00 4827.74 2.74 4825.00 0.00 10.00 50.00 25 SDI-1D FHWA HEC-22 GENERIC N/A On Grade 1 4817.45 4819.82 2.37 4817.45 0.00 N/A 0.00 26 SDI-20B FHWA HEC-22 GENERIC N/A On Grade 1 4815.40 4818.71 3.31 4815.40 0.00 N/A 0.00 27 SDI-21B FHWA HEC-22 GENERIC N/A On Grade 1 4817.20 4820.10 2.90 4816.80 -0.40 N/A 0.00 28 SDI-22B FHWA HEC-22 GENERIC N/A On Grade 1 4823.00 4825.54 2.54 4823.00 0.00 N/A 0.00 29 SDI-23B FHWA HEC-22 GENERIC N/A On Sag 1 4821.65 4824.39 2.74 4821.65 0.00 10.00 50.00 30 SDI-24B FHWA HEC-22 GENERIC N/A On Grade 1 4821.00 4824.96 3.96 4821.00 0.00 N/A 0.00 31 SDI-25B FHWA HEC-22 GENERIC N/A On Grade 1 4822.80 4826.67 3.87 4822.80 0.00 N/A 0.00 32 SDI-26B FHWA HEC-22 GENERIC N/A On Grade 1 4816.20 4818.90 2.70 4815.80 -0.40 N/A 0.00 33 SDI-2A FHWA HEC-22 GENERIC N/A On Grade 1 4812.50 4815.96 3.46 4812.75 0.25 N/A 0.00 34 SDI-2C FHWA HEC-22 GENERIC N/A On Sag 1 4825.15 4827.77 2.62 4825.15 0.00 10.00 50.00 35 SDI-2D FHWA HEC-22 GENERIC N/A On Grade 1 4817.37 4819.82 2.45 4817.37 0.00 N/A 0.00 36 SDI-3A FHWA HEC-22 GENERIC N/A On Grade 1 4811.05 4813.98 2.93 4811.30 0.25 N/A 0.00 37 SDI-3C FHWA HEC-22 GENERIC N/A On Grade 1 4824.15 4827.87 3.72 4824.15 0.00 N/A 0.00 38 SDI-4A FHWA HEC-22 GENERIC N/A On Grade 1 4816.60 4819.77 3.17 4816.60 0.00 N/A 0.00 39 SDI-4B FHWA HEC-22 GENERIC N/A On Sag 1 4821.80 4824.39 2.59 4821.80 0.00 10.00 50.00 40 SDI-4C FHWA HEC-22 GENERIC N/A On Grade 1 4817.50 4821.56 4.06 4817.50 0.00 N/A 0.00 41 SDI-5A1 FHWA HEC-22 GENERIC N/A On Sag 1 4812.40 4815.65 3.25 4812.65 0.25 10.00 50.00 42 SDI-5A2 FHWA HEC-22 GENERIC N/A On Sag 1 4812.65 4815.47 2.82 4812.65 0.00 10.00 50.00 43 SDI-5B FHWA HEC-22 GENERIC N/A On Grade 1 4820.20 4825.57 5.37 4820.20 0.00 N/A 0.00 44 SDI-5C FHWA HEC-22 GENERIC N/A On Grade 1 4817.30 4820.38 3.08 4817.30 0.00 N/A 0.00 45 SDI-6A FHWA HEC-22 GENERIC N/A On Grade 1 4811.95 4815.67 3.72 4812.45 0.50 N/A 0.00 46 SDI-6B FHWA HEC-22 GENERIC N/A On Grade 1 4820.20 4824.96 4.76 4819.90 -0.30 N/A 0.00 47 SDI-6C1 FHWA HEC-22 GENERIC N/A On Sag 1 4817.20 4820.20 3.00 4817.20 0.00 10.00 50.00 48 SDI-6C2 FHWA HEC-22 GENERIC N/A On Sag 1 4817.20 4820.21 3.01 4817.20 0.00 10.00 50.00 49 SDI-7A1 FHWA HEC-22 GENERIC N/A On Sag 1 4814.20 4817.14 2.94 4814.20 0.00 10.00 0.00 50 SDI-7A2 FHWA HEC-22 GENERIC N/A On Sag 1 4814.20 4817.17 2.97 4814.20 0.00 10.00 0.00 51 SDI-7B FHWA HEC-22 GENERIC N/A On Sag 1 4814.70 4817.67 2.97 4814.50 -0.20 10.00 50.00 52 SDI-7C FHWA HEC-22 GENERIC N/A On Grade 1 4817.40 4820.19 2.79 4817.40 0.00 N/A 0.00 53 SDI-8A FHWA HEC-22 GENERIC N/A On Grade 1 4814.00 4817.97 3.97 4814.25 0.25 N/A 0.00 54 SDI-8B1 FHWA HEC-22 GENERIC N/A On Sag 1 4815.00 4817.72 2.72 4814.90 -0.10 10.00 50.00 55 SDI-8B2 FHWA HEC-22 GENERIC N/A On Sag 1 4815.40 4817.72 2.32 4814.90 -0.50 10.00 50.00 56 SDI-8C FHWA HEC-22 GENERIC N/A On Grade 1 4814.95 4817.34 2.39 4814.95 0.00 N/A 0.00 57 SDI-9A FHWA HEC-22 GENERIC N/A On Grade 1 4814.50 4817.96 3.46 4814.50 0.00 N/A 0.00 58 SDI-9B FHWA HEC-22 GENERIC N/A On Sag 1 4815.10 4817.71 2.61 4815.10 0.00 10.00 50.00 59 SDI-9C FHWA HEC-22 GENERIC N/A On Grade 1 4814.30 4817.80 3.50 4814.30 0.00 N/A 0.00 Inlet Results SN Element Peak Peak Peak Flow Peak Flow Inlet Max Gutter Max Gutter Max Gutter Time of Total Total Time ID Flow Lateral Intercepted Bypassing Efficiency Spread Water Elev.Water Depth Max Depth Flooded Flooded Inflow by Inlet during Peak during Peak during Peak during Peak Occurrence Volume Inlet Flow Flow Flow Flow (cfs)(cfs)(cfs)(cfs)(%)(ft)(ft)(ft)(days hh:mm)(ac-in)(min) 1 MH-3C 1.28 1.02 1.08 0.19 84.73 5.35 4823.60 0.21 0 00:20 0.00 0.00 2 SDI-10A 3.02 3.02 2.20 0.82 72.83 6.74 9627.54 0.25 0 00:25 0.00 0.00 3 SDI-10C 1.02 1.02 0.88 0.14 86.19 5.60 4821.81 0.22 0 00:20 0.00 0.00 4 SDI-11A 1.93 1.93 1.56 0.37 80.81 5.59 9627.51 0.22 0 00:23 0.00 0.00 5 SDI-11C 2.56 2.56 1.90 0.66 74.17 6.76 4830.61 0.25 0 00:30 0.00 0.00 6 SDI-12A 1.93 1.93 1.48 0.45 76.80 7.30 4825.26 0.27 0 00:22 0.00 0.00 7 SDI-12B 0.70 0.70 0.65 0.05 92.97 4.08 4821.96 0.17 0 00:19 0.00 0.00 8 SDI-12C 0.70 0.70 0.66 0.04 93.77 3.89 4830.52 0.16 0 00:30 0.00 0.00 9 SDI-13A 0.71 0.71 0.66 0.04 93.76 3.88 4823.03 0.16 0 00:23 0.00 0.00 10 SDI-13B 0.82 0.81 0.74 0.07 91.07 4.39 4821.97 0.18 0 00:19 0.00 0.00 11 SDI-13C 1.19 1.19 1.00 0.19 84.05 5.99 4828.98 0.23 0 00:26 0.00 0.00 12 SDI-14A 1.46 1.23 1.25 0.20 86.01 4.86 4814.17 0.19 0 00:24 0.00 0.00 13 SDI-14B 1.27 1.27 N/A N/A N/A 5.60 4821.04 0.17 0 00:18 0.00 0.00 14 SDI-14C 1.56 1.56 1.27 0.29 81.62 5.80 4825.15 0.22 0 00:20 0.00 0.00 15 SDI-15A 0.34 0.28 N/A N/A N/A 3.33 4817.26 0.15 0 00:24 0.00 0.00 16 SDI-15B 0.68 0.68 N/A N/A N/A 3.85 4820.99 0.12 0 00:18 0.00 0.00 17 SDI-15C 0.87 0.87 0.77 0.10 87.98 5.14 4824.44 0.17 0 00:20 0.00 0.00 18 SDI-16A 2.35 1.91 1.73 0.62 73.69 7.88 4823.95 0.28 0 00:22 0.00 0.00 19 SDI-17A 2.80 2.36 1.99 0.82 70.82 8.46 4822.51 0.30 0 00:23 0.00 0.00 20 SDI-18B 0.30 0.28 0.29 0.00 98.67 3.00 4821.20 0.14 0 00:19 0.00 0.00 21 SDI-19B 1.07 1.07 N/A N/A N/A 5.03 4816.74 0.15 0 00:08 0.00 0.00 22 SDI-1A 0.74 0.74 0.68 0.05 93.03 4.02 4819.92 0.17 0 00:24 0.00 0.00 23 SDI-1C1 0.00 0.00 N/A N/A N/A 4.81 4827.89 0.15 0 00:20 0.00 0.00 24 SDI-1C2 2.06 1.88 N/A N/A N/A 7.55 4827.97 0.23 0 00:19 0.00 0.00 25 SDI-1D 0.99 0.99 0.91 0.08 91.49 4.12 4819.99 0.17 0 00:14 0.00 0.00 26 SDI-20B 1.03 1.03 0.92 0.10 89.99 4.39 4818.89 0.18 0 00:08 0.00 0.00 27 SDI-21B 0.41 0.41 0.40 0.01 96.60 3.56 4820.26 0.15 0 00:20 0.00 0.00 28 SDI-22B 0.92 0.92 0.81 0.11 87.56 5.37 4825.75 0.21 0 00:20 0.00 0.00 29 SDI-23B 1.06 0.86 N/A N/A N/A 5.02 4824.54 0.15 0 00:21 0.00 0.00 30 SDI-24B 1.01 0.85 0.87 0.14 86.32 5.58 4825.17 0.22 0 00:22 0.00 0.00 31 SDI-25B 1.98 1.98 1.51 0.47 76.36 7.37 4826.94 0.27 0 00:14 0.00 0.00 32 SDI-26B 0.39 0.38 0.38 0.01 97.00 3.46 4819.05 0.15 0 00:22 0.00 0.00 33 SDI-2A 1.83 1.79 1.50 0.32 82.25 5.36 4816.17 0.21 0 00:23 0.00 0.00 34 SDI-2C 1.56 1.56 N/A N/A N/A 6.35 4827.96 0.19 0 00:20 0.00 0.00 35 SDI-2D 1.50 1.50 1.28 0.22 85.51 4.92 4820.02 0.20 0 00:14 0.00 0.00 36 SDI-3A 1.87 1.84 1.53 0.34 81.90 5.40 4814.19 0.21 0 00:23 0.00 0.00 37 SDI-3C 0.28 0.28 0.28 0.00 99.93 2.26 4827.99 0.12 0 00:20 0.00 0.00 38 SDI-4A 2.66 2.07 1.95 0.71 73.24 6.97 4820.03 0.26 0 00:24 0.00 0.00 39 SDI-4B 0.88 0.88 N/A N/A N/A 4.50 4824.53 0.14 0 00:20 0.00 0.00 40 SDI-4C 0.94 0.93 0.86 0.09 90.96 4.26 4821.74 0.18 0 00:20 0.00 0.00 41 SDI-5A1 0.31 0.00 N/A N/A N/A 1.96 4815.71 0.06 0 00:23 0.00 0.00 42 SDI-5A2 1.41 1.41 N/A N/A N/A 5.98 4815.65 0.18 0 00:23 0.00 0.00 43 SDI-5B 1.25 1.15 1.04 0.21 83.38 6.10 4825.80 0.23 0 00:19 0.00 0.00 44 SDI-5C 0.98 0.87 0.89 0.09 90.58 4.30 4820.56 0.18 0 00:16 0.00 0.00 45 SDI-6A 1.09 1.09 0.98 0.11 90.35 4.27 4815.84 0.18 0 00:22 0.00 0.00 46 SDI-6B 0.59 0.59 0.56 0.03 94.79 3.78 4825.12 0.16 0 00:20 0.00 0.00 47 SDI-6C1 0.07 0.00 N/A N/A N/A 1.36 4820.24 0.04 0 00:22 0.00 0.00 48 SDI-6C2 1.16 1.02 N/A N/A N/A 5.30 4820.37 0.16 0 00:21 0.00 0.00 49 SDI-7A1 0.35 0.00 N/A N/A N/A 3.37 4817.28 0.15 0 00:24 0.00 0.00 50 SDI-7A2 0.73 0.73 N/A N/A N/A 5.30 4817.45 0.29 0 00:24 0.00 0.00 51 SDI-7B 0.98 0.98 N/A N/A N/A 4.78 4817.81 0.14 0 00:22 0.00 0.00 52 SDI-7C 2.15 2.15 0.35 1.79 16.51 5.74 4820.41 0.22 0 00:22 0.00 0.00 53 SDI-8A 1.79 1.79 1.44 0.35 80.46 5.80 4818.19 0.22 0 00:24 0.00 0.00 54 SDI-8B1 0.00 0.00 N/A N/A N/A 4.81 4817.87 0.15 0 00:21 0.00 0.00 55 SDI-8B2 0.45 0.44 N/A N/A N/A 2.23 4817.79 0.07 0 00:22 0.00 0.00 56 SDI-8C 1.45 1.38 1.25 0.20 86.07 4.85 4817.53 0.19 0 00:21 0.00 0.00 57 SDI-9A 1.76 1.76 1.42 0.34 80.73 5.77 4818.19 0.22 0 00:24 0.00 0.00 58 SDI-9B 1.43 1.43 N/A N/A N/A 5.49 4817.87 0.17 0 00:21 0.00 0.00 59 SDI-9C 4.84 0.51 3.57 1.27 73.77 5.91 4818.11 0.31 0 00:21 0.00 0.00 Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis DESIGN REPORT STORMWATER MANAGEMENT FALLON APARTMENTS Prepared for: Norton Properties, LLC 63020 NE Lower Meadow Road, Suite #200 Bend, OR 97702 Prepared by: C&H Engineering and Surveying, Inc. 1091 Stoneridge Drive, Bozeman, MT 59718 (406) 587-1115 Project Number:200859 May 2021 INTRODUCTION The proposed Fallon Apartments is a 36 dwelling unit residential development located on a 1.4534- acre parcel in Section 2, Township 2 South, Range 5 East of P.M.M., Gallatin County,City of Bozeman. A combination of site grading, curb and gutter,and underground Rainstore retention system will be used to manage stormwater runoff on the site.Supporting stormwater calculations are attached to this report.A Drainage Area Map is included in Appendix A.Calculations for each individual drainage area (total area, weighted C factor,time of concentration, and conveyances) are included in Appendix B, while the underground Rainstore retention system calculations are included in Appendix C. RETENTION DESIGN The underground Rainstore retention system has been sized according to City of Bozeman Design Standards. Retention facilities are sized to capture the entire volume of the 10-year 2-hour storm event.Calculations used for sizing each pond can be found in Appendix C. EXISTING STORMWATER INFRASTURCTURE –NORTON RANCH SUBD. PH. 4 Existing Detention Ponds #1 and #2. There are existing Detention Ponds numbered #1 and #2, which treat stormwater from the underlying Norton Ranch Subdivision and are located in the Norton Ranch Park, just north of May Fly Street.These two detention ponds receive runoff from Lots 2-3, Block 13 via surface flow and gutters within May Fly Street. With the Norton Phase 4 development, these ponds were expanded to account for the proposed development within Phase 4. A C-factor of 0.5 (dense residential) was applied to the entirety Lots 2-3, Block 13. Using 1.4534 acres and a C coefficient of 0.50, the runoff for the 10-year 2-hour storm was calculated to be 2,145 cubic feet.Using the Drainage Area Exhibit of the Norton Ranch Subdivision Phase 4 Stormwater Design Report (February 2018),an analysis carried out in AutoCAD determined that pre-development approximately 55% of the site drained to the existing pond # 1 while 45%drained to pond 2.Therefore, it would be acceptable to allow 1,180 cf of stormwater runoff to discharge to pond 1 and 965 cf to pond 2.As shown later in the report, only 889 cubic feet of runoff is proposed to discharge off site into the adjacent street right of ways.As such,the existing Detention Ponds numbered #1 and #2 have more than adequate capacity to handle the off-site discharge from this development. Drainage Area #1 As shown on the drainage area exhibit, included herein, drainage area #1 consists of the perimeter of the of the property, including the half of building footprints.Stormwater from drainage area #1 is directed northward and eastward into the surrounding roadways via a combination of sheet flow and gutter conveyances. The volume of the 10-year 2-hour storm event results in 889 cubic feet of stormwater, which is allowed to be discharged into the underlying subdivision roads, as previously discussed.Of the 889 cf of runoff from DA 1 approximately 489 cf (55%) will flow into pond 1 and 400 cf (45%)will flow into pond 2. Drainage Area #2 Drainage area #2 consists of the central portion of the property, including the majority of the paved parking area as well and the internal landscape island. Stormwater from drainage area #2 is directed into an underground Rainstore retention system via a combination of sheet flow and gutter conveyances.The volume of the 10-year 2-hour storm event results in 1,293 cubic feet of stormwater. The proposed underground Rainstore retention system was designed with a total volume of 1,262 cubic feet and is therefore adequately sized to retain the 10-year 2-hour storm event.The inlet pipes for the rain store system were designed as 8-in PVC and can carry a flow of 1.19 cfs, this is more than adequate to handle the 25-year storm runoff of 0.64 cfs for the entire DA. Pipe sizing calculations can be found in Appendix C. Drainage Area #3 Drainage area #3 consists of half the western building footprint and the northwest portion of the parking walk with adjacent sidewalks. Stormwater from drainage area #3 is directed into drywell #1 via a combination of sheet flow, downspouts, and gutter conveyances. The volume of the 10- year 2-hour storm event results in 456 cubic feet of stormwater. The proposed drywell was designed with a total volume of 463 cubic feet and is therefore adequately sized to retain the 10- year 2-hour storm event. Drainage Area #4 Drainage area #4 consists of half the eastern building footprint and the northeast portion of the parking walk with adjacent sidewalks. Stormwater from drainage area #4 is directed into drywell #2 via a combination of sheet flow, downspouts, and gutter conveyances. The volume of the 10- year 2-hour storm event results in 457 cubic feet of stormwater. The proposed drywell was designed with a total volume of 463 cubic feet and is therefore adequately sized to retain the 10- year 2-hour storm event. DEPTH TO GROUNDWATER Groundwater monitoring has been conducted by C&H Engineering during the 2018 calendar year and the results are included in Appendix D.The monitoring wells nearest to Lots 2 and 3, Block 13 were used to verify that the proposed stormwater infrastructure for is above the high groundwater table.The property is located halfway between Monitoring Well (MW) #1 and #2. MW#1 and MW#2 had a measured high groundwater recording of approximately 6.1 feet below ground surface and 5.1 feet below ground surface, respectively.The average measured high groundwater between MW#1 and MW#2 is 5.6 feet below ground surface, which is most representative of the groundwater conditions of the property. The bottom of the proposed underground Rainstore retention system is approximately 4.5 feet below grade accounting for the specified profile design. Therefore, the anticipated seasonal-high groundwater depth is not expected to affect the proposed underground Rainstore retention system. Additionally,the bottom of the proposed underground drywells are approximately 5.0 feet below the proposed grade. It should be noted that the proposed grade is about one foot higher than existing grade, in which the previous groundwater depths were measured by. Therefore, the anticipated seasonal-high groundwater depth is not expected to affect the proposed drywells. OFF-SITE RUN-ON CONSIDERATIONS Stormwater run-on from adjacent properties is not expected to adversely impact this development. The surrounding properties have a slight downgradient slope to the north and, as a result, the only run-on would be from the adjacent property to the south, which is currently an undeveloped vegetated pasture. As such, the current conditions would not result is a measurable amount of run-on to this property. Any future development of the adjacent property to the south would be required to contain stormwater runoff within their property and not be allowed to discharge stormwater onto this property per City code. Given the existing and potential future conditions at adjacent properties, off-site run-on would have a negligible effect on this development. APPENDIX A DRAINAGE AREA MAP APPENDIX B DRAINAGE AREA CALCULATIONS RUNOFF VOLUME FROM DA#1 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2 )C * Area Landscape 0.2 15901 3180 Hardscape 0.95 10539 10012 Total 26439 13192 A = Area (acres)0.61 C = Weighted C Factor 0.50 2. Calculate Required Volume Q = CIA V=7200Q C = Weighted C Factor 0.50 I = intensity (in/hr) 0.41 (10 yr, 2hr storm) A = Area (acres)0.61 Q = RUNOFF (cfs)0.12 V = REQUIRED VOL (ft3)889 Check the half inch requirement (per DSSP II.A.4) 1. Determine Area of Hardscape within Drainage Area #1 Contributing Area Area (ft 2 ) Hardscape 10539 2. Calculate 1/2" runoff volume over hardscape (aka Runoff Reduction Volume [RRV] as calculated in Montana Post- Construction Storwater BMP Manual - Equation 3-1) RRV = [P*Rv*A]/12 P = Water quality rainfall depth 0.50 inches Rv = Dimensionless runoff coefficient 0.59 0.05 + 0.9*I I = Percent impervious cover (decimal)0.60 decimal A = Entire drainage area 0.61 acres RRV = Runoff Reduction Volume 0.0150 acre-ft RRV = Runoff Reduction Volume 651 cubic feet Because the runoff volume from the 10-yr, 2-hr storm (for flood control) is greater than the runoff volume produced by the half inch rainfall (for water quality) the larger runoff volume is used (2000 cf). RUNOFF VOLUME FROM DA#2 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2 )C * Area Landscape 0.2 2161 432 Hardscape 0.95 19737 18750 Total 21898 19182 A = Area (acres)0.50 C = Weighted C Factor 0.88 2. Calculate Required Volume Q = CIA V=7200Q C = Weighted C Factor 0.88 I = intensity (in/hr) 0.41 (10 yr, 2hr storm) A = Area (acres)0.50 Q = RUNOFF (cfs)0.18 V = REQUIRED VOL (ft3)1293 Check the half inch requirement (per DSSP II.A.4) 1. Determine Area of Hardscape within Drainage Area #2 Contributing Area Area (ft 2 ) Hardscape 19737 2. Calculate 1/2" runoff volume over hardscape (aka Runoff Reduction Volume [RRV] as calculated in Montana Post- Construction Storwater BMP Manual - Equation 3-1) RRV = [P*Rv*A]/12 P = Water quality rainfall depth 0.50 inches Rv = Dimensionless runoff coefficient 0.14 0.05 + 0.9*I I = Percent impervious cover (decimal)0.10 decimal A = Entire drainage area 0.50 acres RRV = Runoff Reduction Volume 0.0029 acre-ft RRV = Runoff Reduction Volume 127 cubic feet Because the runoff volume from the 10-yr, 2-hr storm (for flood control) is greater than the runoff volume produced by the half inch rainfall (for water quality) the proposed Rainstore 3 retention facility is sized to handle the larger volume (1,077 cf). RUNOFF VOLUME FROM DA#3 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2 )C * Area Landscape 0.2 453 91 Hardscape 0.95 7022 6671 Total 7475 6762 A = Area (acres)0.17 C = Weighted C Factor 0.90 2. Calculate Required Volume Q = CIA V=7200Q C = Weighted C Factor 0.90 I = intensity (in/hr) 0.41 (10 yr, 2hr storm) A = Area (acres)0.17 Q = RUNOFF (cfs)0.06 V = REQUIRED VOL (ft3)456 Check the half inch requirement (per DSSP II.A.4) 1. Determine Area of Hardscape within Drainage Area #3 Contributing Area Area (ft 2 ) Hardscape 7022 2. Calculate 1/2" runoff volume over hardscape (aka Runoff Reduction Volume [RRV] as calculated in Montana Post- Construction Storwater BMP Manual - Equation 3-1) RRV = [P*Rv*A]/12 P = Water quality rainfall depth 0.50 inches Rv = Dimensionless runoff coefficient 0.10 0.05 + 0.9*I I = Percent impervious cover (decimal)0.06 decimal A = Entire drainage area 0.17 acres RRV = Runoff Reduction Volume 0.0007 acre-ft RRV = Runoff Reduction Volume 33 cubic feet Because the runoff volume from the 10-yr, 2-hr storm (for flood control) is greater than the runoff volume produced by the half inch rainfall (for water quality) the proposed drywell #1 is sized to handle the larger volume (456 cf). RUNOFF VOLUME FROM DA#4 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2 )C * Area Landscape 0.2 452 90 Hardscape 0.95 7047 6694 Total 7498 6785 A = Area (acres)0.17 C = Weighted C Factor 0.90 2. Calculate Required Volume Q = CIA V=7200Q C = Weighted C Factor 0.90 I = intensity (in/hr) 0.41 (10 yr, 2hr storm) A = Area (acres)0.17 Q = RUNOFF (cfs)0.06 V = REQUIRED VOL (ft3)457 Check the half inch requirement (per DSSP II.A.4) 1. Determine Area of Hardscape within Drainage Area #4 Contributing Area Area (ft 2 ) Hardscape 7047 2. Calculate 1/2" runoff volume over hardscape (aka Runoff Reduction Volume [RRV] as calculated in Montana Post- Construction Storwater BMP Manual - Equation 3-1) RRV = [P*Rv*A]/12 P = Water quality rainfall depth 0.50 inches Rv = Dimensionless runoff coefficient 0.10 0.05 + 0.9*I I = Percent impervious cover (decimal)0.06 decimal A = Entire drainage area 0.17 acres RRV = Runoff Reduction Volume 0.0007 acre-ft RRV = Runoff Reduction Volume 33 cubic feet Because the runoff volume from the 10-yr, 2-hr storm (for flood control) is greater than the runoff volume produced by the half inch rainfall (for water quality) the proposed drywell #2 is sized to handle the larger volume (457 cf). MANNING'S EQUATION FOR PIPE FLOW Project: 0 Location: 0 By: 0 Date: 0 Chk. By: 0 Date: 0 INPUT D= 8 inches d= 7.503546 inches Mannings Formula n= 0.01 mannings coeff 57.7 degrees Q=(1.486/n)ARh2/3S1/2 S= 0.005 slope in/in R=A/P A=cross sectional area P=wetted perimeter V=(1.49/n)Rh2/3S1/2 S=slope of channel Q=V x A n=Manning's roughness coefficient Solution to Mannings Equation Area,ft2 Wetted Perimeter, ft Hydraulic Radius, ft velocity ft/s flow, cfs PVC 0.01 0.34 1.76 0.19 3.51 1.19 PE (<9"dia) 0.015 PE (>12"dia) 0.02 PE(9-12"dia) 0.017 CMP 0.025 ADS N12 0.012 HCMP 0.023 Conc 0.013 Manning's n-values d  D DRAINAGE AREA # 2 25-YR OUTFLOW RATE REQUIRED CAPACITY 1. Calculate Weighted C Factor for Right-of-Way Component Width C ROW Hardscape 41 0.95 ROW Landscape 19 0.2 Weighted C Factor = 0.71 1. Calculate Area and Weighted C Factor (Post-Development) Contributing Area C Area (ft 2 )C * Area Composite ROW 0.71 0 0 Landscape 0.2 2161 432 Hardscape 0.35 19737 6908 Dense Residential 0.5 0 0 Commercial Neighborhood 0.6 0 0 Commercial Downtown 0.8 0 0 Industrial 0.8 0 0 Total 21898 7340 A = Area (acres) 0.5027 C = Weighted C Factor 0.34 2. Calculate Rainfall Intensity (Duration = Max Tc from Contributing Drainage Areas) i = 0.78x-0.64 (10-yr Storm, Fig. I-3, COB Design Standards) x = storm duration (hrs) 0.08 (DA #2) i = rainfall intensity (in./hr.) 3.83 3. Calculate 25-yr Pond Outflow Rate Q = CiA C = Rational Method Runoff Coefficient 0.34 (calculated above) i = rainfall intensity (in./hr.) 3.83 (calculated above) A = Area (acres) 0.50 (calculated above) Q = 25-yr Flow Rate (cfs) 0.64 RUNOFF VOLUME FROM DA#2 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2) C * Area Landscape 0.2 2161 432 Hardscape 0.95 19737 18750 Total 21898 19182 A = Area (acres)0.50 C = Weighted C Factor 0.88 2. Calculate Required Volume Q = CIA V=7200Q C = Weighted C Factor 0.88 I = intensity (in/hr) 0.41 (10 yr, 2hr storm) A = Area (acres) 0.50 Q = RUNOFF (cfs)0.18 V = REQUIRED VOL (ft3)1293 Check the half inch requirement (per DSSP II.A.4) 1. Determine Area of Hardscape within Drainage Area #2 Contributing Area Area (ft 2) Hardscape 19737 2. Calculate 1/2" runoff volume over hardscape (aka Runoff Reduction Volume [RRV] as calculated in Montana Post- Construction Storwater BMP Manual - Equation 3-1) RRV = [P*Rv*A]/12 P = Water quality rainfall depth 0.50 inches Rv = Dimensionless runoff coefficient 0.14 0.05 + 0.9*I I = Percent impervious cover (decimal)0.10 decimal A = Entire drainage area 0.50 acres RRV = Runoff Reduction Volume 0.0029 acre-ft RRV = Runoff Reduction Volume 127 cubic feet Because the runoff volume from the 10‐yr, 2‐hr storm (for flood control) is  greater than the runoff volume produced by the half inch rainfall (for water quality)  the proposed retention facility  is sized to handle the larger volume (1,293 cf). CALCULATE RAINSTORE VOLUME # Rows= 6 3.28' x 3.28' x 4" Stackable Units (TYP.) # Columns = 8 System Depth= 2.60 ft Standard depths (0.7, 1.0, 1.3, 2.0, 2.6, 4.0, and 7.9) Total System Volume = 1343 cf Void Space = 94% *assumed no fill Pro Retention Volume=1262 cf Req Vol =1293 cf APPENDIX D GROUNDWATER MONITORING DATA APPENDIX E NORTON PHASE 4 STORMWATER DESIGN REPORT Approximate Project Location Project Engineer:Matt H Project: Well Information:bgs = below ground surface ags = above ground surface MW-1 MW-2 MW-3 MW-4 10'10'10'10' 0.58 1.71 0.71 0.92 Groundwater Information: MW-1 MW-2 MW-3 MW-4 02/14/18 6.81 6.29 4.20 4.38 03/13/18 6.94 6.39 4.20 4.34 04/13/18 6.10 5.10 3.12 3.30 05/11/18 6.87 6.36 4.20 4.35 05/25/18 6.78 6.18 4.14 4.31 06/08/18 6.99 6.62 4.37 4.54 06/22/18 6.30 6.51 4.48 4.60 07/06/18 8.64 8.21 5.91 6.10 07/20/18 7.49 7.32 4.85 5.10 08/03/18 7.47 7.32 4.85 5.21 08/17/18 7.57 7.10 5.00 5.21 08/30/18 7.15 6.82 4.50 4.70 09/14/18 7.25 6.85 4.65 4.80 Monitor Well Data Project Number:161140 Norton East Ranch Subdivision, Phase 4 Project Location:Bozeman Well ID Well Depth (feet-bgs) Top of Well (feet-ags) Date Depth to Ground Water (feet-bgs) BB+z z2:1 Δσ EtBqH DCompressible soil layerRigid soil layer APPENDIX E NORTON PHASE 4 STORMWATER DESIGN REPORT DESIGN REPORT STORMWATER MANAGEMENT NORTON RANCH SUBDIVISION, PHASE 4 Prepared for: Norton Properties, LLC 63020 NE Lower Meadow Road, Suite A, Bend, OR 97702 Prepared by: C&H Engineering and Surveying, Inc. 1091 Stoneridge Drive, Bozeman, MT 59718 (406) 587-1115 Project Number: 161140 February 2018 INTRODUCTION The proposed Norton Ranch Subdivision, Phase 4 is a 21-lot subdivision located on a 15.58-acre parcel in the East Half and the West Half of Section 9, Township 2 South, Range 5 East of P.M.M., Gallatin County, City of Bozeman. A combination of site grading, curb and gutter, storm inlets, and piping will be used to manage stormwater runoff on the site. The stormwater infrastructure used in this phase is all existing and was installed with Norton Ranch Subdivision, Phase 1. Supporting stormwater calculations are attached to this report. A Drainage Area Map is included in Appendix A. Calculations for each individual drainage area (total area, weighted C factor, and time of concentration) are included in Appendix B. RETENTION/DETENTION POND DESIGN All ponds have been sized according to City of Bozeman Design Standards. Retention ponds are sized to capture the entire volume of the 10-year 2-hour storm event. They are designed with An effective depth of 1.5 feet, and maximum side slope of 4:1. Existing Detention Pond 1 and Existing Detention Pond 2 are sized to limit discharge to pre-development rates for the 10-year storm event. Both ponds have been sized to retain the first 0.5 inches of rain before the outlet structure begins to discharge. Calculations used for sizing each pond can be found in Appendix C. Design pond capacities were calculated using volume surfaces in AutoCAD Civil3D. Existing Detention Pond #1 Existing Detention Pond #1 is located north of May Fly Street, between Bull Frog Drive and Laurel Parkway. It receives runoff from Drainage Areas 1, 2, 3, and 4, totaling 8.66 acres. The pond currently receives runoff from Norton Ranch Subdivision, Phase 1. The existing pond volume is 2,904 cubic feet at an effective water depth of 1.5’. For Norton Ranch Subdivision, Phase 4, the pre-development time to concentration was calculated to be 40 minutes and the pre-development runoff rate for the 10-yr storm was calculated to be 1.43 cfs. The existing outlet structure discharges into the existing wetland area in the park to the north. The outlet structure will need to be raised to retain the first 0.5 inches of stormwater runoff. The new flow out elevation will be set to 4804.25’ and the slot will be expanded to a width of 2.8”. The new required pond volume was calculated to be 8,964 cubic feet. The new provided pond volume is 9,146 cubic feet at an effective water depth of 1.5’ above the seasonal high groundwater level (see Appendix D and the Geotechnical Investigation Report for Phase 4). See construction plans for the expansion of the pond and modifications to the outlet structure. In the case of a storm exceeding the 10-yr design storm, runoff will overflow the outlet structure top grate into the outlet pipe and flow into the existing wetland area. Supporting calculations for the pond sizing can be found in Appendix C. Existing Detention Pond #2 Existing Detention Pond #2 is located north of May Fly Street, between Bull Frog Drive and Laurel Parkway. It receives runoff from Drainage Areas 5, 6, 7, and 8, totaling 14.58 acres. The pond currently receives runoff from Norton Ranch Subdivision, Phase 1. The existing pond volume is 6,072 cubic feet at an effective water depth of 1.5’. For Norton Ranch Subdivision, Phase 4, the pre-development time to concentration was calculated to be 58 minutes and the pre-development runoff rate for the 10-yr storm was calculated to be 1.91 cfs. The existing outlet structure discharges into the existing wetland area in the park to the north. The outlet structure will need to be raised to retain the first 0.5 inches of stormwater runoff. The new flow out elevation will be set to 4803.50’ and the slot will be expanded to a width of 3.7”. The new required pond volume was calculated to be 14,321 cubic feet. The new provided pond volume is 14,915 cubic feet at an effective water depth of 1.5’ above the seasonal high groundwater level (see Appendix D and the Geotechnical Investigation Report for Phase 4). See construction plans for the expansion of the pond and modifications to the outlet structure. In the case of a storm exceeding the 10-yr design storm, runoff will overflow the outlet structure top grate into the outlet pipe and flow into the existing wetland area. Supporting calculations for the pond sizing can be found in Appendix C. APPENDIX A DRAINAGE AREA MAP APPENDIX B DRAINAGE AREA CALCULATIONS DRAINAGE AREA #1 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 12158 8967 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 72612 36306 Existing Development 0.5 0 0 Total 84771 45273 A = Area (acres) 1.95 C = Weighted C Factor 0.53 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 1.46 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 249 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)18.57 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.52% L = length of gutter (ft) 214 V = mean velocity (ft/s) 2.17 Tc Gutter Flow (minutes) =1.64 Tc Total = 20.21 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.53 (calculated above) I = 0.78 Tc-0.64 (in/hr)1.56 (25-yr storm) A = area (acres) 1.95 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 1.63 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.52% Q = PROVIDED GUTTER CAPACITY (cfs) 2.69 DRAINAGE AREA #2 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 11868 8752 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 0 0 Existing Development 0.5 0 0 Total 11868 8752 A = Area (acres) 0.27 C = Weighted C Factor 0.74 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 2.00 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 23 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)5.11 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.52% L = length of gutter (ft) 285 V = mean velocity (ft/s) 2.17 Tc Gutter Flow (minutes) =2.20 Tc Total = 7.31 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.74 (calculated above) I = 0.78 Tc-0.64 (in/hr)3.00 (25-yr storm) A = area (acres) 0.27 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 0.60 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.52% Q = PROVIDED GUTTER CAPACITY (cfs) 2.69 DRAINAGE AREA #3 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 60231 44420 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 189509 94755 Existing Development 0.5 0 0 Total 249740 139175 A = Area (acres) 5.73 C = Weighted C Factor 0.56 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 0.86 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 350 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)26.30 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.07% L = length of gutter (ft) 784 V = mean velocity (ft/s) 3.10 Tc Gutter Flow (minutes) =4.21 Tc Total = 30.51 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.56 (calculated above) I = 0.78 Tc-0.64 (in/hr)1.20 (25-yr storm) A = area (acres) 5.73 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 3.84 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.07% Q = PROVIDED GUTTER CAPACITY (cfs) 3.85 DRAINAGE AREA #4 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 30818 22728 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 0 0 Existing Development 0.5 0 0 Total 30818 22728 A = Area (acres) 0.71 C = Weighted C Factor 0.74 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 1.18 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 25 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)6.31 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.27% L = length of gutter (ft) 663 V = mean velocity (ft/s) 3.38 Tc Gutter Flow (minutes) =3.27 Tc Total = 9.59 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.74 (calculated above) I = 0.78 Tc-0.64 (in/hr)2.52 (25-yr storm) A = area (acres) 0.71 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 1.32 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.27% Q = PROVIDED GUTTER CAPACITY (cfs) 4.19 DRAINAGE AREA #5 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 6870 5067 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 18920 9460 Existing Development 0.5 0 0 Total 25790 14527 A = Area (acres) 0.59 C = Weighted C Factor 0.56 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 1.73 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 206 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)16.00 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.50% L = length of gutter (ft) 82 V = mean velocity (ft/s) 2.12 Tc Gutter Flow (minutes) =0.64 Tc Total = 16.65 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.56 (calculated above) I = 0.78 Tc-0.64 (in/hr)1.77 (25-yr storm) A = area (acres) 0.59 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 0.59 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.50% Q = PROVIDED GUTTER CAPACITY (cfs) 2.63 DRAINAGE AREA #6 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 56228 41468 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 120620 60310 Existing Development 0.5 0 0 Total 176848 101778 A = Area (acres) 4.06 C = Weighted C Factor 0.58 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 0.90 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 170 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)18.05 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.56% L = length of gutter (ft) 569 V = mean velocity (ft/s) 3.74 Tc Gutter Flow (minutes) =2.53 Tc Total = 20.58 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.58 (calculated above) I = 0.78 Tc-0.64 (in/hr)1.55 (25-yr storm) A = area (acres) 4.06 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 3.61 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 1.56% Q = PROVIDED GUTTER CAPACITY (cfs) 4.64 DRAINAGE AREA #7 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 9297 6856 Park 0.2 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 0 0 Existing Development 0.5 0 0 Total 9297 6856 A = Area (acres) 0.21 C = Weighted C Factor 0.74 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 2.00 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 26 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)5.42 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.31% L = length of gutter (ft) 165 V = mean velocity (ft/s) 1.66 Tc Gutter Flow (minutes) =1.66 Tc Total = 7.08 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.74 (calculated above) I = 0.78 Tc-0.64 (in/hr)3.06 (25-yr storm) A = area (acres) 0.21 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 0.48 (assuming no carry flow) PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.31% Q = PROVIDED GUTTER CAPACITY (cfs) 2.06 DRAINAGE AREA #8 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 54523 40211 Park 0.2 35811 7162 Low-Med Density Residential 0.35 0 0 Dense Residential 0.5 91442 45721 Existing Development 0.5 241552 120776 *See Norton Ranch Phase Total 423328 213870 1 Stormwater Design Report for C Factor A = Area (acres) 9.72 C = Weighted C Factor 0.51 2. Calculate Tc (Time to Concentration) Tc Overland Flow Tc = 1.87 (1.1-CCf)D1/2/S1/3 Storm S = Slope of Basin (%) 1.17 Return (yrs)Cf C = Rational Method Runoff Coefficient 0.35 2 to 10 1 Cf = Frequency Adjustment Factor 1.1 11 to 25 1.1 D = Length of Basin (ft) 160 26 to 50 1.2 51 to 100 1.25 Tc Overland Flow (minutes)16.05 Tc Gutter Flow Tc = L/V/60 V = (1.486/n)R2/3 S1/2 n = Mannings Coefficient 0.013 R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.91% L = length of gutter (ft) 845 V = mean velocity (ft/s) 2.86 Tc Gutter Flow (minutes) =4.93 Tc Total = 20.98 3. Calculate Flow (Rational Formula) Q = CIA C = Weighted C Factor 0.51 (calculated above) I = 0.78 Tc-0.64 (in/hr)1.53 (25-yr storm) A = area (acres) 4.17 (calculated above) Q = REQUIRED GUTTER CAPACITY (cfs) 3.27 (assuming no carry flow) *Note: The existing development was removed for gutter capacity calculations due to a different time of concentration. PROVIDED GUTTER CAPACITY 1. Calculate Gutter Capacity @ 0.15' Below Top of Curb Q = (1.486/n)AR2/3 S1/2 n = Mannings Coefficient 0.013 A = Area (ft2)1.24 (0.15' below top of curb) P = Wetted perimeter (ft) 9.23 (0.15' below top of curb) R = Hydraulic Radius A/P (ft) 0.13 (0.15' below top of curb) S = slope (%) 0.91% Q = PROVIDED GUTTER CAPACITY (cfs) 3.55 APPENDIX C POND SIZING CALCULATIONS EXISTING DETENTION POND # 1 REQUIRED VOLUME 1. Calculate Area and Weighted C Factor (Post-Development) Contributing Area C Area (ft 2 )C * Area Composite ROW 0.74 115074 84867 OS/Park 0.20 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.50 262121 131061 Existing Development 0.50 0 0 Total 377196 215928 A = Area (acres) 8.66 Storm C = Weighted C Factor 0.57 Return (yrs)Cf 2 to 10 1 2. Calculate T c (Pre-Development)11 to 25 1.1 Tc Overland Flow 26 to 50 1.2 Tc = 1.87 (1.1-CCf)D1/2/S1/3 51 to 100 1.25 S = Slope of Basin (%) 1.47 C = Rational Method Runoff Coefficient 0.2 Cf = Frequency Adjustment Factor 1.1 D = Length of Basin (ft) 780 Tc (Pre-Development) (minutes) 40 3. Calculate Rainfall Intensity (Duration = Pre-Development Tc) i = 0.64x-0.65 (10-yr Storm, Fig. I-3, COB Design Standards) x = storm duration (hrs) 0.67 (Tc Pre-Development) i = rainfall intensity (in./hr.) 0.83 4. Calculate Runoff Rate (Pre-Development) Q = CiA C = Rational Method Runoff Coefficient 0.2 (open land) i = rainfall intensity (in./hr.) 0.83 (calculated above) A = Area (acres) 8.66 (calculated above) Q = Runoff Rate (Pre-Development) (cfs) 1.43 5. Calculate Required Pond Volume Total Area (acres) = 8.66 acres Weighted C = 0.57 Discharge Rate (cfs) = 1.43 cfs (Equal to Pre-Development Runoff Rate) Duration(min) Duration(hrs) Intensity (in/hr)Qin (cfs)Runoff Volume Release Volume Required Storage (ft3) 35 0.58 0.91 4.50 9457 516 8942 36 0.60 0.89 4.42 9551 602 8949 37 0.62 0.88 4.34 9643 688 8955 38 0.63 0.86 4.27 9734 774 8960 39 0.65 0.85 4.20 9823 860 8963 40 0.67 0.83 4.13 9910 946 8964 41 0.68 0.82 4.06 9996 1032 8964 42 0.70 0.81 4.00 10081 1118 8963 43 0.72 0.79 3.94 10164 1204 8960 44 0.73 0.78 3.88 10246 1290 8956 *Note: The outlet structure will not release any water until the initial 8,923 CF of runoff from the first 0.5"of rain has been retained. This occurs within the first 29 minutes of the storm event. PROVIDED VOLUME (ft3)9,146 OUTLET STRUCTURE SLOT Q=CLH3/2 Q = Discharge (cfs) 1.43 C = Weir Coefficient 3.33 (per COB Design Standards) H = Head (ft) 1.5 L = Horizontal Length (ft) 0.23 L = Slot Width (inches) 2.8 DETENTION POND #1 REQUIRED STORAGE FOR FIRST 0.5 INCHES OF RAIN FROM 24-HOUR STORM EVENT REQUIRED VOLUME 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft 2 )C * Area Composite ROW 0.74 115074 84867 Park 0.20 0 0 Low-Med Density Residential 0.35 0 0 Dense Residential 0.50 262121 131061 Existing Development 0.50 0 0 Total 377196 215928 C=Weighted C Factor 0.57 2. Calculate Required Volume Q = CIA V=22194Q C = Weighted C Factor 0.57 I = intensity (in/hr) 0.08 (10 yr, 24 hr storm) A = Area (acres) 8.66 Q = runoff (cfs) 0.40 V = REQUIRED VOL (ft3)8923 *A 10-year, 24-hour storm event produces 0.5" of rain after 6.165 hours. (I=0.0811in/hr --> 0.5in / 0.0811in/hr = 6.165 hours) **The required volume was calculated by using the 6.165 hours it takes to produce the 0.5" of rain. (6.165hr * 60min/hr * 60sec/min * Q = 22194Q) EXISTING DETENTION POND # 2 REQUIRED VOLUME 1. Calculate Area and Weighted C Factor (Post-Development) Contributing Area C Area (ft 2 )C * Area Composite ROW 0.74 126918 93602 OS/Park 0.20 35811 7162 Low-Med Density Residential 0.35 0 0 Dense Residential 0.50 230982 115491 Existing Development 0.50 241552 120776 *See Norton Ranch Phase Total 635263 337031 1 Stormwater Design Report for C Factor A = Area (acres) 14.58 Storm C = Weighted C Factor 0.53 Return (yrs)Cf 2 to 10 1 2. Calculate T c (Pre-Development)11 to 25 1.1 Tc Overland Flow 26 to 50 1.2 Tc = 1.87 (1.1-CCf)D1/2/S1/3 51 to 100 1.25 S = Slope of Basin (%) 1.02 C = Rational Method Runoff Coefficient 0.2 Cf = Frequency Adjustment Factor 1.1 D = Length of Basin (ft) 1261 Tc (Pre-Development) (minutes) 58 3. Calculate Rainfall Intensity (Duration = Pre-Development Tc) i = 0.64x-0.65 (10-yr Storm, Fig. I-3, COB Design Standards) x = storm duration (hrs) 0.97 (Tc Pre-Development) i = rainfall intensity (in./hr.) 0.65 4. Calculate Runoff Rate (Pre-Development) Q = CiA C = Rational Method Runoff Coefficient 0.2 (open land) i = rainfall intensity (in./hr.) 0.65 (calculated above) A = Area (acres) 14.58 (calculated above) Q = Runoff Rate (Pre-Development) (cfs) 1.91 5. Calculate Required Pond Volume Total Area (acres) = 14.58 acres Weighted C = 0.53 Discharge Rate (cfs) = 1.91 cfs (Equal to Pre-Development Runoff Rate) Duration(min) Duration(hrs) Intensity (in/hr)Qin (cfs)Runoff Volume Release Volume Required Storage (ft3) 45 0.75 0.77 5.97 16119 1833 14286 46 0.77 0.76 5.89 16243 1947 14296 47 0.78 0.75 5.80 16366 2062 14305 48 0.80 0.74 5.72 16487 2176 14311 49 0.82 0.73 5.65 16607 2291 14316 50 0.83 0.72 5.57 16724 2405 14319 51 0.85 0.71 5.50 16841 2520 14321 52 0.87 0.70 5.43 16956 2634 14321 53 0.88 0.69 5.37 17069 2749 14320 54 0.90 0.69 5.30 17181 2863 14318 *Note: The outlet structure will not release any water until the initial 13,927 CF of runoff from the first 0.5"of rain has been retained. This occurs within the first 29 minutes of the storm event. PROVIDED VOLUME (ft3)14,915 OUTLET STRUCTURE SLOT Q=CLH3/2 Q = Discharge (cfs) 1.91 C = Weir Coefficient 3.33 (per COB Design Standards) H = Head (ft) 1.5 L = Horizontal Length (ft) 0.31 L = Slot Width (inches) 3.7 DETENTION POND #2 REQUIRED STORAGE FOR FIRST 0.5 INCHES OF RAIN FROM 24-HOUR STORM EVENT REQUIRED VOLUME 1. Calculate Area and Weighted C Factor Contributing Area C Area (ft2 )C * Area Composite ROW 0.74 126918 93602 OS/Park 0.20 35811 7162 Low-Med Density Residential 0.35 0 0 Dense Residential 0.50 230982 115491 Existing Development 0.50 241552 120776 Total 635263 337031 C=Weighted C Factor 0.53 2. Calculate Required Volume Q = CIA V=22194Q C = Weighted C Factor 0.53 I = intensity (in/hr) 0.08 (10 yr, 24 hr storm) A = Area (acres) 14.58 Q = runoff (cfs) 0.63 V = REQUIRED VOL (ft3)13927 *A 10-year, 24-hour storm event produces 0.5" of rain after 6.165 hours. (I=0.0811in/hr --> 0.5in / 0.0811in/hr = 6.165 hours) **The required volume was calculated by using the 6.165 hours it takes to produce the 0.5" of rain. (6.165hr * 60min/hr * 60sec/min * Q = 22194Q) APPENDIX D POND PROFILES 0'100'200'300'AS NOTEDGROUNDWATERMONITORINGMALHEC May 18, 2022 - 2:35pmCAD FILE: M:\203430\Drawings\PA 17, 26\EXHIBITS\WELL LOCATION.dwg REVISIONSDATEPROJECT NUMBERHYALITE Engineers, PLLC2304 N 7th Ave. Ste. LBozeman, MT 59715Tel: (406) 587.2781w w w . hyaliteeng. comFax: (406) 522.92252018URBAN + FARM BOZEMAN, MT5/18/2022203430PRELIMINARY 22x34 ORIGINALSSCALESHEET TITLEDESIGN BYOUTLAW PARTNERS11 LONE PEAK DRIVEBIG SKY, MT 59716PHASE 1URBAN + FARM PHASE 1MAJOR SUBDIVISIONGROUNDWATER MONITORINGLEGAL DESCRIPTIONLOT R2A OF NORTON EAST RANCH PHASE 4, LOCATEDIN THE SOUTH 12 OF SECTION 9, TOWNSHIP 2 SOUTH,RANGE 5 EAST, PRINCIPAL MERIDIAN MONTANA,GALLATIN COUNTY, MONTANA.MW # 1MW # 2MW # 3MW # 4SOUTH LAUREL PARKWAY MAY FLY STREETFALLON STREET1OF 1MAYFLY MW # 2MAYFLY MW # 1URBAN + FARM PHASE 2URBAN + FARM PHASE 1MAYFLY URBAN + FARMPHASE 1Groundwater MonitoringDate: 10/19/2022By: Miguel Ley, EIProject #: 203430DATE MW#1 (ft) MW#2 (ft) MW#3 (ft) MW#4 (ft)7-May-213.76 3.73 3.20 4.6014-May-213.55 3.47 2.96 4.2620-May-212.56 3.62 3.02 4.0526-May-212.68 2.50 2.77 3.602-Jun-212.84 3.20 2.88 3.9811-Jun-213.16 3.28 2.91 3.9017-Jun-213.40 3.36 2.96 4.2224-Jun-213.51 3.60 3.09 4.302-Jul-213.16 3.84 3.19 4.489-Jul-212.76 3.69 3.09 4.3716-Jul-212.86 3.84 3.16 4.4722-Jul-213.58 3.87 3.18 4.7629-Jul-214.04 4.01 3.28 4.969-Aug-216.31 6.59 2.98 4.6020-Aug-213.88 2.54 2.57 4.3730-Aug-213.91 3.39 2.93 4.7610-Sep-214.06 3.59 2.93 4.8615-Sep-214.01 3.54 2.88 4.8025-Oct-213.96 4.53 2.63 4.745-Nov-213.92 3.52 2.67 4.9912-Nov-213.95 3.64 2.99 5.0418-Nov-213.96 3.71 3.05 5.0124-Nov-213.97 3.75 3.09 4.992-Dec-213.95 3.78 3.10 4.9213-Dec-213.98 3.83 3.20 5.0022-Dec-213.95 3.82 3.12 4.981-Jan-223.97 3.91 3.18 5.0013-Apr-223.69 3.38 2.83 4.5623-Apr-223.44 1.74 2.48 4.011-May-223.11 0.64 2.38 3.914-May-222.71 2.42 0.11 3.4111-May-222.86 2.73 0.78 3.6918-May-223.11 1.91 2.64 3.9924-May-223.33 2.64 2.73 4.001-Jun-22 2.67 0.58 2.37 3.158-Jun-22 2.62 0.55 2.37 3.0714-Jun-22 2.97 0.26 2.55 3.4220-Jun-22 3.39 2.33 2.66 4.0428-Jun-22 3.36 3.23 2.93 4.266-Jul-22 1.91 2.90 2.93 4.1513-Jul-22 3.11 3.52 2.94 4.3818-Jul-22 4.36 2.66 2.68 4.5128-Jul-223.733.622.964.823-Aug-222.922.262.894.6512-Aug-223.450.802.614.6916-Aug-223.681.232.924.8130-Aug-223.823.713.975.106-Sep-223.983.903.185.1213-Sep-223.823.773.065.0020-Sep-223.833.472.894.770.001.002.003.004.005.006.007.004-Jan-21 14-Apr-21 23-Jul-21 31-Oct-21 8-Feb-22 19-May-22 27-Aug-22 5-Dec-22DEPTH (ft.)DATEDEPTH TO GROUNDWATERMW#1 (ft)MW#2 (ft)MW#3 (ft)MW#4 (ft)L:\203430\Computations\GROUNDWATER MONITORING\Groundwater Monitoring SSSSBT BT BT BT BT BT BT BT BT BTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTSSSSSSSSFIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE WS WS WS WS WS WS WSSDSDSDSDSD■■■■■■■■■■■■SDSDSDSD SD SDSDSD SD SDSDSD SD SD SD SDSDSDSD SD SD SD SDSDSDSDSDSDSDSDSDSDSDSDSDSDSD SD SD SD SD SD SDSDSDS D SD SDSDSDSDSDSDSDSD SD SD SD SD SDSDSDSDSD■■FIREFIREFIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE FIRE WSWS WS WS WS WS WS WS FIREFIREDYH SDSDSDFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOSDSDSDSDSDSDSDSDSDSDSDSDSDSDFOFOFO FOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOFOWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWHYDW W HYDHYDSSS SSSSSSSSSS SSSSSSSSSSWXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXOHPOHPBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBTBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBF BFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBFBTBTBTBTBTBTBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVBTVS89°08'28"W 1106.17'S2°47'19"E 270.48'N89°08'29"E 1087.93'N1°04'34"E 270.49'N89°11'22"E 302.41'R=11539.16'L=403.74'Δ=2°00'17"CB=S88°11'15"WCH=403.72'N87°13'55"E 248.59'9.16'5.14'6'04"55'05"E85.13'60'90'24.59'N73°41'53"E43.40'25'4825482448234822482148204819481848214822482448234824FG: 26.07GW: 22.19FG: 26.07GW: 21.41FG: 21.15GW: 19.09FG: 29.59GW: 24.06FG: 29.59GW: 23.32FG: 25.30GW: 22.564829482 8 4 82 6 48234829482848274826FIGURE NUMBER©PROJECT NO.DRAWN BY:DSGN. BY:APPR. BY:DATE:COPYRIGHT MORRISON-MAIERLE,2025Plotted by rosie nickelson on Apr/1/2025engineers surveyors planners scientistsMorrisonMaierle2880 Technology Blvd WestBozeman, MT 59718406.587.0721www.m-m.netN:\10549\002 - ALTA and Concept Plan\ACAD\Exhibits\10549.002_Post-Development_Drainage.dwg 10549.002APP A.ROERS BOZEMAN APARTMENTSBOZEMANMTGROUNDWATER EXHIBITRSNRSNCMSNOV 2024408020400SCALE IN FEETBASIN P-2BASIN 3(DETENTION POND AFROM URBAN+FARM)BASIN P-1VALLEY COMMONS DRIVELAUREL PARKWAYHUFFINE LANEBUILDING AFFE = 4826.07BUILDING BFFE = 4829.59ELEVATOR PIT LOCATION (TYP.)G Gallatin County I i MClerk & Recorder Map Planning & Zoning Map Environmental Health Map Sc Find address or place City of Bozeman, Montana, Maxar | Madison, James P., 2022, Potentiometric surface in Gallatin, Lower Ma…Powered by Esri A T T A I N S D a t a F E M A S t r u c t u r e s M B M G G W I C W el l MAP LAY Gallati n City Count y E i 3/19/25, 10:00 AM Environmental Health Map | Gallatin County Mapper https://experience.arcgis.com/experience/6c5d3097540f4895be52c11b0bda0731/page/Environmental-Health-Map?print_preview=true#widget_12=acti…1/1