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Home My WebLink About008 Nexus Point Water Design Report WATER DESIGN REPORT FOR: NEXUS POINT MULTI-UNIT RESIDENTIAL & OFFICE DEVELOPMENT BOZEMAN, MT Prepared By: Madison Engineering 895 Technology Drive, Suite 203 Bozeman, MT 59718 (406) 586-0262 March 2023 Nexus Point Development Water Design Report Page 1 of 3 NEXUS POINT DEVELOPMENT WATER SYSTEM DESIGN REPORT A. General This design report will give an overview of the proposed water main extension for the development of Nexus Point Multi-Unit Residential & Office Building Development Infrastructure Improvements. The proposed Phase 1 improvements are anticipated to be constructed during the fall of 2019. Once the water main is constructed and approved, the main will become a part of the City of Bozeman system. The following references were used in the preparation of this report: a. COB Design Standards and Specifications Policy, 2017. Addendum #6 b. COB Modifications to Montana Public Works Standard Specifications (MPWSS). c. WQB Circular No. 1 d. City of Bozeman Zoning Map e. City of Bozeman Water Facility Plan f. 2015 International Fire Code Existing System The proposed water main extension will be served by the existing City of Bozeman water distribution system, which will be looped. The two connection locations are the existing stub of Lantern Lane and future stub at intersection of Lantern Lane and S 21st Avenue, which will continue south and connect to the intersection of Graf Street and S 21st Avenue. The following information was obtained by the City of Bozeman at the intersection of Lantern Lane and Enterprise Boulevard. Fire Hydrants: 2077 Static Pressure: 65 psi Pitot Pressure: 56 psi Residual pressure: 57 psi Hydrant discharge: 1,250 gpm from 2.5” port Distribution Main Capacity – Fire flow at minimum residual pressure Qr = Qt[(Ps – Pm)/(Ps – Pt)]0.54 Qr = 1,250 [(65 –20)/(65 – 56]0.54 Qr = 2,981 gpm at 20 psi Qt = Hydrant Discharge during Test Qr = Fire Flow at Residual Pressure Ps = Static Pressure Pm = Minimum Residual Pressure = 20 psi Pr = Residual Pressure Pt = Pitot Pressure Nexus Point Development Water Design Report Page 2 of 3 B. Proposed Water System The proposed water main extension for the Nexus Point development consists of approximately 2,499 linear feet of 8” ductile iron pipe that will connect to the existing water main stub on Lantern Lane and at the future intersection of Lantern Lane and S 21st Avenue, which is to be installed with the Graf Street Apartment project. The layout of the proposed water main meets the COB design criteria and will be located within the easements/right of way and separated from the proposed sanitary sewer main by a minimum of 10 feet horizontally. Fire hydrants will be installed per COB design criteria and will not exceed the recommended distance. C. Capacity Analysis The Nexus Point development water main extension is proposed for the development of the 14- buildings comprised of 262-units (120 units in Phase 1 & 142 in Phase 2), 2 – office buildings and 1- café unit which sits on an estimated 19.99 acres of R-O (Residential Office District) zoned land. An estimation of the water flow rate was based on the City of Bozeman’s design standards and specification policy, which suggests using an average daily flow rate of 2.11 people per dwelling unit and 170-gallons per capita per day. Applied to the 240 units, the required water flow rate is calculated: (𝟐𝟓𝟐 𝐫𝐧𝐢𝐫𝐫∗2.11 residents unit ∗170 gallons capita day )= 𝟗𝟐,𝟗𝟓𝟗 gpd The 2 future office buildings consist of 11,300 sf and 9,900 sf at full build out. Based on a conservative basis the office buildings will use 0.273 gpd/sf. per water supply planning book by David W. Prasifka. Taking these factors into consideration the office buildings will contribute: (0.273 gallons per day square feet ∗(11,300 +9,900)square feet )= 12,985 gpd One building located within phase 2, is set to include a café/restaurant. Based on a conservative basis the café will use 55 gpd/unit per water supply planning book by David W. Prasifka. Taking this into consideration the café will contribute: (𝟓𝟓 𝐠𝐚𝐥𝐥𝐧𝐧𝐫 𝐧𝐜𝐫 𝐜𝐚𝐲 𝐫𝐜𝐚𝐫∗𝟓𝟗 𝐫𝐜𝐚𝐫𝐫/𝐧𝐜𝐜𝐫𝐧𝐚𝐧𝐫𝐫 )=𝟐,𝟓𝟗𝟓 𝐠𝐧𝐜 Based on these parameters, the development at full build out (262 units + 2 office buildings + cafe) will have an estimated water usage of 110,759 gpd (76.91 gpm). The main will connect to the existing City of Bozeman system and will serve the future Nexus Point apartment buildings. In addition to the average daily demand, the water main extension must account for peak periods of daily use. Peaking factors are applied to the demand and account for these peak periods in daily use. The peaking factors used are maximum daily use and peak hour and are obtained from the City of Bozeman Design Standards. Table 1 shows the peaking factors and the resultant flows from those factors when applied to the average daily demand of 76.91 gpm. Nexus Point Development Water Design Report Page 3 of 3 TABLE 1 PEAKING FACTORS Flow Designation Peaking Factor Flow (gpm) Average Day Demand 1 76.91 Maximum Day Demand 2.3 176.89 Maximum Hour Demand 3 230.73 Based on communication with the architect, five types of buildings will be installed and will consist of two (2) – multi-floor office buildings, six (6) – 12 plex 2-bedroom units, and two (2) – 24 plex 2-bedroom units, three (3) – 36 plex 1 & 2 – bedroom units and one (1) - 34 plex 1 & 2 bedroom units that includes a Café, along with a club house for a total of 15 individual future buildings. The square footage for each type of building are as follows: 12 Plex = 12,552sf, 24 Plex = 24,046sf, 34 Plex/Cafe = 48,692sf, 36 Plex = 48,731sf, and the club house = 9,989sf. The units are expected to be type V-A and V-B construction with fire sprinklers. A Type V-A 48,731 sf building requires 4,000 gpm for a 4-hour flow duration per the 2015 International Fire Code, Table B105.1(2). The flow capacity for the largest building was chosen to be more conservative. Based on the 2015 International Fire Code’s Table B105.2, the 4,000 gpm fire flow can be reduced but shall not be less than the minimum of 1,500 gpm. Results Based on the analysis outlined above, the required minimum fire flow is 1,500 gpm and the maximum hour demand is 230.73 gpm. The combination of these results is a maximum hour flow of 1,730.73 gpm. The attached WaterCAD analysis was designed to incorporate the maximum hour demand throughout the system. A fire flow analysis was performed at each node throughout the system (including the base max. hour demand) where a building has a potential fire flow demand. The flow analysis shows that an 8-inch DI pipe can provide the development with the required flow of 1,730.73 gpm and remain above the minimum pressure of 20 psi. See attached flow analysis for calculations. D. Conclusion Based on this analysis, the proposed 8-inch ductile iron water main serving the Nexus Point residential development extension provides adequate service to meet the 262-unit, 2–Office Building and 1-Cafe peak hour demand and fire flows requirements for the development. The water main was designed on conservative premise for future development. For instance, only one connection point (intersection of Lantern Lane and Enterprise Blvd.) was modeled, when in reality there will be two connection points for the system. The water main design is consistent with the City of Bozeman Water Facility Plan. This project will require the approval of the City of Bozeman Engineer and MDEQ. Fire Flow Node FlexTable: Fire Flow Report Fire Flow (Available) (gpm) Fire Flow (Needed) (gpm) Satisfies Fire Flow Constraints? Fire Flow Iterations ZoneLabel 1,7541,500True3<None>J-2 1,9131,500True2<None>J-23 1,9131,500True2<None>J-25 1,8911,500True5<None>J-26 1,7721,500True6<None>J-33 1,9131,500True2<None>J-35 1,9131,500True2<None>J-38 1,9131,500True2<None>J-40 1,9131,500True2<None>J-42 1,9131,500True2<None>J-44 1,9131,500True3<None>J-46 1,9131,500True2<None>J-58 1,7651,500True6<None>J-62 1,9131,500True2<None>J-64 1,9131,500True2<None>J-71 1,8271,500True6<None>J-75 Pressure (Calculated Zone Lower Limit) (psi) Pressure (Zone Lower Limit) (psi) Pressure (Calculated Residual) (psi) Pressure (Residual Lower Limit) (psi) Flow (Total Available) (gpm) Flow (Total Needed) (gpm) 232020201,7541,500 272028201,9131,500 242026201,9131,500 202023201,8911,500 202023201,7721,500 252025201,9131,500 212024201,9131,500 232026201,9131,500 242026201,9131,500 222025201,9131,500 202023201,9131,500 232023201,9131,500 202023201,7651,500 222024201,9131,500 222025201,9131,500 202023201,8271,500 Is Fire Flow Run Balanced? Junction w/ Minimum Pressure (System) Pressure (Calculated System Lower Limit) (psi) Pressure (System Lower Limit) (psi) Junction w/ Minimum Pressure (Zone) TrueJ-123(N/A)J-1 TrueJ-227(N/A)J-2 TrueJ-224(N/A)J-2 TrueJ-220(N/A)J-2 TrueJ-220(N/A)J-2 TrueJ-925(N/A)J-9 TrueJ-221(N/A)J-2 TrueJ-223(N/A)J-2 Page 1 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 3/9/2020 WaterCAD CONNECT Edition Update 2 [10.02.00.43] Bentley Systems, Inc. Haestad Methods Solution CenterNexus Point WaterCad.1.wtg Fire Flow Node FlexTable: Fire Flow Report Is Fire Flow Run Balanced? Junction w/ Minimum Pressure (System) Pressure (Calculated System Lower Limit) (psi) Pressure (System Lower Limit) (psi) Junction w/ Minimum Pressure (Zone) TrueJ-224(N/A)J-2 TrueJ-222(N/A)J-2 TrueJ-220(N/A)J-2 TrueJ-223(N/A)J-2 TrueJ-220(N/A)J-2 TrueJ-222(N/A)J-2 TrueJ-222(N/A)J-2 TrueJ-220(N/A)J-2 Page 2 of 227 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 3/9/2020 WaterCAD CONNECT Edition Update 2 [10.02.00.43] Bentley Systems, Inc. Haestad Methods Solution CenterNexus Point WaterCad.1.wtg