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Home My WebLink About16 - Design Report - Graf Street Extension - Water WATER MAIN EXTENSION DESIGN REPORT FOR: GRAF STREET EXTENSION BOZEMAN, MT Prepared By: MADISON ENGINEERING Madison Engineering 895 Technology Drive, Suite 203 Bozeman, MT 59718 (406) 586-0262 APRIL 2016 APR 12 2016 ; i OF COMMUNITY DEVELOPMENT WATER MAIN EXTENSION DESIGN REPORT FOR: GRAF STREET EXTENSION BOZEMAN, MT Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 CHRIS BUDC S APRIL 2016 ° 1� 5�' 9 w GRAF STREET EXTENSION WATER SYSTEM DESIGN REPORT A. General This design report will give an overview of the proposed water main extension for the extension of Graft Street from S. 19th Ave to MacNab Street in Bozeman. Improvements are anticipated to be constructed during the summer of 2016. 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,2004. Addendum#5 b. COB Modifications to Montana Public Works Standard Specifications(MPWSS). c. WQB Circular No. l d. City of Bozeman Zoning Map e. City of Bozeman Water Facility Plan f. 2012 International Fire Code B. Existing Water Supply The proposed water main extension will connect the existing City of Bozeman water distribution system in Graf Street at the intersections of S. 19th Ave and MacNab Street via existing 24" stubs. The following information regarding pressures of the existing system were obtained from the City of Bozeman: Hydrants 1475 & 1474 (Graf St. & Teslow Drive) -East End of Main Static Pressure: 65 psi Pitot Pressure: 40 psi Residual Pressure: 63 psi Hydrant Discharge: 1060 gpm during test, 2.5" port Distribution Main Capacity—Fire flow at minimum residual pressure Qr=Qt[(Ps—Pm)/(P,—Pr)]0.14 Qr= 1,060[(65—20)/(65—63)]0.14 Qr=5,695 gpm at 20 psi Qt= Hydrant Discharge During Test Qr= Fire Flow at Minimum Residual Pressure Ps= Static Pressure P," = Minimum Residual Pressure Pr = Residual Pressure Pt= Pitot Pressure C. Proposed Water System The proposed water main extension consists of connecting to the existing City of Bozeman system at the intersections of Graf Street with S. 19th Ave and MacNab Street. The existing 24" mains will be connected with approximately 3,207 linear feet of ductile iron main along the proposed Graft Street alignment. The main will connect to the existing.24" main in MacNab Graf Street Extension Water Design Report Page I of 3 Street with a 24" butterfly valve. The main will be 24" ductile iron until the intersection of S. llth Ave, where it will be reduced to 12" to S. 19th Ave and connected to the existing 24" ductile iron stub with a 12"x24" reducer and a 24" butterfly valve. Twelve inch stubs are proposed in S. 1 lth Ave for future looping of the water system. Eight-inch stubs are proposed at all other intersections to provide service to the future residential development, per City of Bozeman Standards. The proposed water main is sized and located in accordance with City of Bozeman Water Facility Plan, Figure 5.13.8, provided in the Appendix. The layout of the proposed water main meets the City of Bozeman design criteria and will be located within the proposed right-of ways and separated from the proposed sanitary sewer main by a minimum distance of 10 feet. Fire hydrants will be installed so not to exceed 600' spacing, fulfilling the distance requirement for fire hydrant spacing, as well as`assisting in flushing of the main. Y D. Capacity Analysis The Graf Street water main extension is proposed for the development for the Yellowstone Theological Institute, which includes 80 acres of R-1 (residential low density) and R-2 (residential medium density) zoning. At full build-out, the main extension will serve approximately 69.8 acres of R-1 and 10.2 acres of R-2 development. Based on Table 4.13.4 of the City of Bozeman Water Facility Plan, the City's design standards for an R-1 and R-2 residential lot is 3.9 and 5.2 units per gross acre, respectively. The analysis was completed based on 170 gpd per capita usage and 2.11 persons per unit. The main will be looped into the existing City of Bozeman system and served from both ends, however calculations were based on a dead end line to be conservative. The water main extension has been designed to meet the maximum day demand plus fire flow during the peak hour. TABLE 1 WATER DEMAND—RESIDENTIAL Units/ Density Total Daily Flow Flow Zoning Acres acre (residents/unit) Residents Rate/resident d R-1 69.8 3.9 2.11 575 170 97,750 R-2 10.2 5.2 2.11 112 170 19,040 Total Flow d 116,790 Total Flow m) 243 Base on these parameters, the 80 acre development, at full build out, will have an estimated water usage of 116,790 gal/day, or an average daily demand of 243 gpm, based on an 8-hour day. 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 2 shows the peaking factors and the resultant flows from those factors when applied to the average daily demand of 243 gpm. Graf Street Extension Water Design Report 2 Page of 3 TABLE 2 PEAKING FACTORS Flow Designation Peaking Factor Flow m Average Day Demand 1 243 Maximum Day Demand 2.3 559 Maximum Hour Demand 3 729 The required fire flow for a residential structure is 1,500 gpm per the 2012 International Fire Code, Table B 105.1. A Hazen-Williams "C" Factor of 130 was used in the pipe evaluation. The working residual water pressure shall not be less than 20 psi at any point in the water distribution system under maximum day plus fire flow. The velocity shall not exceed 15 feet per second through the main line. Results Based on the analysis outlined previously, the required fire flow is 1,500 gpm, and with the maximum hour demand of 729 gpm a maximum hour flow of 2,229 gpm is required. Flow analysis shows that a 12-inch D.I. pipe with a C value of 130 can provide 2,229 gpm with a pressure drop of approximately 16.4 psi from 65 psi to 48.6 psi, well above the minimum of 20 psi. The pipe velocity is 6.32 ft/s. Capacity analysis calculations outlining the capacity of the proposed 12-inch pipe are included in the appendix of this report. E. Conclusion Based on this analysis, the proposed 12-inch & 24-inch Graf Street water main extension for the development of the Yellowstone Theological Institute Subdivision provides adequate service to meet the peak hour demand and fire flows for the subdivision. The water main design is consistent with the City of Bozeman Water Facility Plan. This project will require the approval of the City Engineer and MDEQ. Appendix 1. Capacity Calculations 2. City of Bozeman Water Facility Plan, Figure 5.13.8 Graf Street Extension Water Design Report Page 3 of 3 Capacity Calculations YTI Water Main Capacity Analysis Project Description Friction Method Hazen-Williams Formula Solve For Pressure at 2 Input Data Pressure 1 65.00 psi Elevation 1 4975.13 ft Elevation 2 4976.21 ft Length 3288.00 ft Roughness Coefficient 1X000 Diameter 12,00 in Discharge 2229.00 gal/min Results Pressure 2 48.58 psi Headloss 3639 ft Energy Grade 1 5125.68 ft Energy Grade 2 5088.88 ft Hydraulic Grade 1 5125.06 ft Hydraulic Grade 2 5088.26 ft Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Velocity 6.32 ft/s Velocity Head 0.62 ft Friction Slope 0.01119 ft/ft Bentley Systems,Inc. 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