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Home My WebLink About21 - Design Report - Lot 4 Block 2 Opportunity Subdivision (Town Pump 6) - Water WATER MAIN EXTENSION DESIGN REPORT FOR: LOT 4 BLOCK 2 OPPORTUNITY SUBDIVISION BOZEMAN, MT Prepared By: OtATA MADISON . . 'caAr,Is G. Bum's� ENGINEERING = 2 �E , rNAL� Madison Engineering 895 Technology Drive, Suite 203 Bozeman, MT 59718 (406) 586-0262 March 2021 OPPORTUNITY SUBDIVISION—LOT 4 WATER SYSTEM DESIGN REPORT A. General This design report will give an overview of the proposed short 8" water main extension for the future development of Lot 4 Block 2 of the Opportunity Subdivision located on North I9th at Kimberwicke Street. The report includes a description of the proposed water main extension and design parameters. The proposed improvements are anticipated to be constructed during the spring of 2021. Once the water main is constructed and approved, the main will become a part of the City of Bozeman(COB) system. This main will not be put into use until future development is reviewed and approved by the City for Lot 4. It is being constructed only to be installed under a parking lot that will be paved for the recently approved Town Pump 6 Lounge. 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 and City of Bozeman Water Facility Plan e. 2015 International Fire Code B. Existing Water Supply The proposed water main extension will be served from the existing COB water distribution system in Kimberwicke. The following information regarding pressures of the existing system obtained from the COB: Hydrants 1953 & 1786 (N. 19th& Cattail St.) Static Pressure: 96 psi Pitot Pressure: 74 psi Residual Pressure: 86 psi Hydrant Discharge: 1,445 gpm during test, 2.5" port Distribution Main Capacity—Fire flow at minimum residual pressure Q,=Qc[(Ps—Pm)/(PS—p,)]0.54 Q,= 1,445[(96—20)/(96—86)]0.54 Q,=4,320 gpm at 20 psi Qt= Hydrant Discharge During Test Q,= Fire Flow at Minimum Residual Pressure P5= Static Pressure Pm = Minimum Residual Pressure Pr = Residual Pressure P,= Pitot Pressure Opportunity Subdivision—Lot 4 Water Design Report Page 1 of 3 C. Proposed Water System The proposed water main extension will connect to an ext'g 8" stub in Kimberwicke and consists of approximately 135 linear feet of Class 51 Ductile Iron Pipe and extend north into Lot 4. The proposed main will be looped in the future with the future development of Lot 4. The layout of the proposed water main meets the COB design criteria and will be centered within a 30' wide water main easement. A gate valve will be installed at the connection point to the existing main per City standards. A blow-off will be installed at the end of the line, that will be extended in the future. D. Capacity Analysis A capacity analysis was performed on the proposed water main extension. The water main extension has been designed to meet the maximum day demand plus fire flow during the peak hour. The main will ultimately serve Lot 4 which is 7.4 acres and zoned B-2, community business. The City's Design Standards does not specifically reference water usage for B-2 zoning so we propose to use the Sanitary Sewer Design Criteria for evaluating the water usage. Based on Table V-1 of the City's design standards, it is estimated a B-2 lot will produce 2,000 gpd of wastewater flow per acre. Based on this value, the 7.4 acres, at full build out, will have an estimated wastewater discharge of 14,800 gal/day. Assuming wastewater usage is comparable to water usage, this equates to an average daily water demand of 10.3 gpm (0.023 cfs). 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 COB Design Standards. Table 1 shows the peaking factors and the resultant flows from those factors applied to the average daily demand of 23 gpm. TABLE 1 PEAKING FACTORS Flow Designation Peaking Factor Flow (gpm) Average Day Demand 1 10.3 Maximum Dav Demand 2.3 23.64 Maximum Hour Demand 3 30.83 The required fire flow for a Type V-B structure up to 13,400 sf structure is 3,000 gpm. Based on a fire flow demand of 3,000 gpm and a maximum hour demand of 31 gpm, a maximum hour flow of 3,031 gpm is required. However, a 75% reduction in fire flow is allowed when a building is provided with an automatic sprinkler system, which all buildings developed on the B- 2 property will likely have. Based on the allowed reduction, the required fire flow is 750 gpm. TABLE 2 Opportunity Subdivision—Lot 4 Water Design Report Page 2 of 3 ANTICIPATED FLOWS Flow Designation Residential Fire Demand Total Flow Demand m m ( m) Maximum Day 23.64 750 773.6 Maximum Hour 30.83 750 780.8 The total demand during maximum hour, including fire flow, is 780.8 gpm. 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 The analysis was performed based on a dead-end main. Flow analysis of the 8-inch D.I. pipe with a C value of 130 can provide the required 780.8 gpm with a pressure drop of approximately 9 psi from 86 psi to 77 psi, well above the minimum of 20 psi. with a maximum pipe velocity is 5.38 ft/s. Capacity analysis calculations outlining the capacity of the proposed 8-inch pipe is included in the appendix of this report. E. Conclusion Based on this analysis, the proposed 8-inch and 12-inch water main extensions for the development of the proposed Opportunity Subdivision provide adequate service to meet the peak hour demand, irrigation demand, and fire flows for the development. This project will require the approval of the City Engineer and MDEQ. Appendix 1. Water Main Capacity Analysis 2. Hydrant Pressure/Flow Test Opportunity Subdivision—Lot 4 Water Design Report Page 3 of 3 1 � � 2 O 4 2 O Shaping Our Future Together CITY OF BOZEMAN HYDRANT PRESSURE/FLOW REQUEST FORM Date: 6/2/16 Location Hydrant# Static Pressure Pitot Pressure Residual Pressure N. 19` /Cattail St. 1953 96 86 Cattail W. of N. 19th 1786 74 Requested By: Brianna Baker Fax# Nozzle Size Flowed: 2.5" Done By: ES /CD Comments: 1445 GPM 2360 I �% ♦ j •1954 Q 1101 1100 1099 • 1 04 CA-1Rj S 1416 1418 1169 1415 ,, 1261 1260 1414 1408 • I ♦ • 2694 1257�I,R 1258 1445 14" 1417 •1409 1262 _- • I� ST 1259 5 ! 1338 1166 1757 \��I `'1170 1443 2364 23db • ¢ 1337 !1762 17,61 \�1436�� • • 1756 17591 0 2165 2000 436- ♦ \\, \1442 • • 1760 ♦2+I4 11 1 1439— ♦ I� 1838 14 3 J • 1441.1� "1"164 *CAT f_ IL.ST 1953 165-71785-- 1493 _ 1172 1163 �117��