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Home My WebLink About1 - Water and Sewer Design Report 2021.08.13 Design Report - Page 2 of 7 INTRODUCTION The proposed Fallon Apartments project includes the construction of 22 condominium units on Lots 1 and 2, Block 14 of Norton Ranch Subdivision, Phase 4. The property is fronted on three sides by City streets with Pond Lily Drive, Fallon Street, and Water Lily Drive being adjacent to the west, north and east property boundaries, respectively. Water and sanitary sewer mains are located within Pond Lily Drive, Fallon Street, and Water Lily Drive, surrounding the subject property. WATER DISTRIBUTION SYSTEM The water main extension plan involves a proposed 8” D.I.P. water main that would connect at two points to the existing 8” water main in Pond Lily Drive and Water Lily Drive along the southern portion of the property as shown on the civil plan set. 1” and 1.5” copper water services will be extended off of this 8” water main to the proposed condominium buildings. It should be noted that there are existing water and fire services stubbed into the property from Pond Lily Drive and Water Lily Drive as shown on the civil plan set. The existing service stubs are not located in a feasible location to serve the buildings given the site layout and will all be abandoned at the main. A WaterCAD analysis is enclosed (Appendix A of this report) for the main to be installed with this project. The connection to the existing system is modeled as a pump with characteristics matching pressure/flow data from the existing hydrant at the intersection of Water Lily Drive and Fallon Street. This existing flow data, provided by the City of Bozeman, was used to approximate the pressure and flow for the water main the project area. Water Distribution System Demands The design parameters used herein are according to the City of Bozeman Design Standards and Specifications Policy (DSSP) dated May 2017. Average Daily Residential Usage = 170 gallons per capita per day Average Population Density = 2.17 persons/dwelling unit Design Report - Page 3 of 7 Minimum Fire Hydrant Flow = 1,500 gpm Residual Pressure Required = 20 psi for Fire Flow Average Day Demand (Peaking Factor = 1.0) Maximum Day Demand (Peaking Factor = 2.3) Peak Hour Demand (Peaking Factor = 3.0) Water Demands (11 dwelling units) Average Day Demand = 22 d.u. x 2.17 persons/d.u. x 170 gpcpd = 8,116 gpd = 5.64 gpm Maximum Day Demand = 5.64 gpm x 2.3 = 12.97 gpm Peak Hour Demand = 5.64 gpm x 3.0 = 16.92 gpm Water Distribution System Hydraulic Analysis A water distribution model was created using WaterCAD Version 6.5 for demand forecasting and describing domestic and fire protection requirements. In order to model the system, each junction node of the water distribution system was assessed a demand based on its service area. The table shown below quantifies the demands placed at the junction nodes and calculates the demands for Average Day, Maximum Day and Peak Hour within the project. The peaking factor for each case is 1.0, 2.3 and 3.0 respectively. Refer to the site layout in Appendix A for node locations. Static, residual and pitot pressures were provided by the City of Bozeman Water Department for Hydrant #2407 on the 8” water main in Fallon Street at the SW corner of the intersection with Water Lily Drive. Email correspondence with the City of Bozeman Water Department regarding the hydrant data is provided in Appendix A of this report for reference. Location Hydrant # Static Pressure (PSI) Pitot Pressure (PSI) Residual Pressure (PSI) Fallon Street / Water Lily Drive 2407 58 48 54 Design Report - Page 4 of 7 Pump Curve Calculations: Pump #1 (Hydrant at Water Lily and Fallon) Static Pressure (Ps) = 58 Pitot Pressure (Pp)= 48 Residual Pressure (Pr) = 54 Qf = 1575 Q=Qf*((Ps-P)/(Ps-Pr))(0.54) Pressure Flow Head 54 1575.00 124.62 49 2440.39 113.08 44 3097.97 101.54 39 3653.38 90.00 34 4144.60 78.46 29 4590.53 66.92 24 5002.27 55.38 19 5386.95 43.85 14 5749.53 32.31 9 6093.60 20.77 4 6421.86 9.23 DEMAND JUNCTION NODE DWELLING UNITS (D.U.) POPULATION (RES.) 2.17 PEOPLE PER D.U. AVERAGE DAY GPM (170 GALLONS PER DAY PER PERSON) MAX. DAY GPM PEAK HOUR GPM DJ 1 11 24 2.8 6.5 8.5 DJ 2 11 24 2.8 6.5 8.5 Total 22 48 5.64 12.96 16.91 *See Demand Junction Map for more information on which lots contribute to each Demand Junction. This flow/pressure information was used to develop relationships between static head and flow at the tie in point to the existing water main. This relationship was simulated in the WaterCAD model, where it is modeled as a pump with characteristics matching pressure/flow data from the existing hydrant. The pump was placed in Fallon Street, north of the tie in point of the proposed Design Report - Page 5 of 7 water main and is connected to a reservoir which acts as a source of water. The elevation of the reservoir is fixed at the elevation of the pump. The input data and the pump curve are included in Appendix A of this report. Water Distribution System Design Summary The model shows that the existing water distribution system provides adequate flow and pressure for the proposed project. The modeled connection point (pump) in Fallon Street supplied sufficient pressure to the system. All of the junction nodes in the water model read 20 psi. The proposed 8-inch, D.I.P. water main in Fallon Street provides adequate capacity to serve the project. The flows and pressures within the system for the Peak Hour Demands were generated using WaterCAD and can be found in Appendix A of this report. The capacity of the system to meet fire flow requirements was tested by running a steady state fire flow analysis for all junctions. The model shows that the junction at this existing hydrant satisfies fire flow constraints (residual pressure > 20 psi, flow rate > 1500 gpm), while providing service to the condominium buildings at peak hour. The results of the analysis at peak hourly flow are given in Appendix A of this report. SANITARY SEWER SYSTEM An existing 8” sanitary sewer main is located in Fallon Street and terminated with a manhole (COB No. M0559) along the northwestern corner of the property, as shown on the civil plans. A proposed 8” sanitary sewer main will be extended from this manhole, eastward along Fallon Street, and then southward into the property. 19 of the proposed units will be serviced by 4” sewer services connected to this new main. There are two existing 4” sewer services stubbed into the property from Pond Lily Drive and Water Lily Drive, respectively. The two existing service stubs along Water Lily Drive would both be utilized to serve two (2) of the proposed units. However, only one of the existing service stubs along Pond Lily Drive would be utilized while the other would be abandoned at the main. Design Report - Page 6 of 7 Sanitary Sewer Design Load The population estimates of 2.17 people per dwelling unit, and residential flow rate of 64.4 gpcd used herein are according to the City of Bozeman Design Standards and Specifications. The peaking factor for the design area is determined using the formula provided in the City of Bozeman Design Standards and Specifications. The proposed main extension will be 8-inch and shall be sized to flow at no more than 75% of capacity for peak hour conditions. Using the city average of 2.17 persons per household the equivalent population is calculated. Connection: Equivalent Population = (2.17 persons/dwelling unit)(19 units) = 41 persons Harmon Formula: Peaking Factor = (18 + P0.5)/(4 + P0.5) where: P = Population in thousands Peaking Factor = (18 + 0.0410.5)/(4 + 0.0410.5) Peaking Factor = 4.33 Assumed infiltration rate = 150 gallons/acre/day = 150 (2.099 acres) = 315 gal/day The peak flow rate is calculated by multiplying the City's design generation rate of 64.4 gallons per capita per day by the population, multiplying by the peaking factor, and adding the infiltration rate: Peak Flow Rate = 64.4 gpcpd (41 persons) (4.33) + 315 gpd = 11,748 gpd = 8.16 gpm = 0.018 cfs The capacity of an 8-inch main is checked using Manning’s Equation: Qfull = (1.486/0.013)AR2/3S1/2 For an 8-inch PVC main: Manning's n = 0.013 for PVC Pipe Minimum Slope = 0.004 ft/ft A = area = (3.14/4)d 2 = (3.14/4)(8/12)2 = 0.34907 ft2 Design Report - Page 7 of 7 P = perimeter = 2(3.14)r = 2(3.14)(4/12) = 2.0944 ft R = hydraulic radius = A/P = 0.34907/2.0944 = 0.16667 ft R2/3 = 0.30105 ft S = 0.004 ft/ft S1/2 = 0.0632 ft/ft Qfull = (1.486/0.013)(0.34907)(0.30105)(0.0632) = 0.7592 cfs Connection: Q/Qfull = 0.018 /0.7592 = 0.024 or 2.40% Based on these calculations, an 8-inch sewer line has adequate capacity to carry the design flows for the project. It should be noted that the downstream sanitary sewer discharge is received by the Norton Ranch Lift Station, which is currently at capacity. It is understood that upgrades to the Norton Ranch Lift Station are currently in the design review phase, which has prepared by HDR. The proposed upgrades to the lift station would significantly increase the capacity of the lift station to allow for this development. It is understood that approval of the future infrastructure plans cannot be issued until the lift station updates are complete. We respectfully request that site plan review is allowed to proceed on the assumption the that lift station upgrades will be completed this during late-summer 2021. APPENDIX A WaterCAD Model Results Scenario: Base P8 P5 P3 P1 DJ2 DJ1 J-5J-4J-1 J-17J-18 WATER LILY AND FALLON HYDRANT R-2 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203-755-16668/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg FlexTable: Junction Table Pressure (psi) Hydraulic Grade (ft) Demand (gpm) Demand Collection ZoneElevation (ft) LabelID 584,951.790<Collection: 0 items><None>4,817.34J-133 594,951.799<Collection: 1 items><None>4,815.87DJ235 594,951.799<Collection: 1items><None>4,815.68DJ137 584,951.790<Collection: 0 items><None>4,816.97J-439 584,951.790<Collection: 0items><None>4,817.78J-541 594,951.790<Collection: 0 items><None>4,815.99J-1775 594,951.790<Collection: 0 items><None>4,815.68J-1877 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg FlexTable: Pipe Table Length (User Defined) (ft) Velocity (ft/s) Flow (gpm) Minor Loss Coefficient (Local) Hazen-Williams C MaterialDiameter (in) Stop NodeStart NodeLength (Scaled) (ft) Label 1200.11-170.000130.0Ductile Iron8.0J-5J-4120P5 2270.11-170.000130.0Ductile Iron8.0J-17J-5183P4 320.11-170.390130.0Ductile Iron8.0J-18J-1742P3 270.19170.000130.0Ductile Iron6.0J-18WATER LILY AND FALLON HYDRANT23P2 10.00170.000130.0Ductile Iron99.0WATER LILY ANDFALLONHYDRANTR-233P1 960.11-170.000130.0Ductile Iron8.0J-4DJ196P7 2630.05-90.000130.0Ductile Iron8.0DJ1DJ2263P8 960.0000.000130.0Ductile Iron8.0J-1DJ296P9 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg FlexTable: Pump Table Pump Head (ft) Flow (Total) (gpm) Hydraulic Grade (Discharge) (ft) Hydraulic Grade (Suction) (ft) Status (Initial)Pump DefinitionElevation (ft) Label 133.85174,951.804,817.95OnWater Lil and Fallon Hydrants-4,817.95 WATER LILY AND FALLON HYDRANT Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg Fire Flow Node FlexTable: Fire Flow Report Junction w/ Minimum Pressure (Zone) Pressure (Calculated Residual) (psi) Pressure (Residual Lower Limit) (psi) Flow (Total Available) (gpm) Flow (Total Needed) (gpm) Fire Flow (Available) (gpm) Fire Flow (Needed) (gpm) Label DJ220201,9361,5001,9361,500J-1 J-120202,0481,5082,0401,500DJ2 J-120202,3701,5082,3611,500DJ1 J-120202,5481,5002,5481,500J-4 J-120202,8131,5002,8131,500J-5 J-520203,8141,5003,8141,500J-17 J-520204,3031,5004,3031,500J-18 Page 1 of 176 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg Pump Definition Detailed Report: Water Lil and Fallon Hydrants- Element Details 73ID Notes Water Lil and Fallon Hydrants- Label Pump Curve Head(ft)Flow(gpm) 124.621,575 113.082,440 101.543,098 90.003,653 78.464,145 66.924,591 55.385,002 43.855,387 32.315,749 20.776,094 9.236,421 Pump Efficiency Type Best Efficiency Point Pump Efficiency Type %100.0Motor Efficiency %100.0BEP Efficiency FalseIs Variable Speed Drive? gpm0BEP Flow Transient (Physical) lb·ft²0.000Inertia (Pump and Motor)SI=25, US=1280Specific Speed rpm0Speed (Full)TrueReverse Spin Allowed? Page 1 of 276 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg Pump Definition Detailed Report: Water Lil and Fallon Hydrants- Page 2 of 276 Watertown Road, Suite 2D Thomaston, CT 06787 USA +1-203- 755-1666 8/3/2021 WaterCAD [10.03.04.05]Bentley Systems, Inc. Haestad Methods Solution Center200860_WaterCAD.wtg