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Home My WebLink About18 - Design Report - Glen Lake Subdivision - Water, Sewer WATER & SEWER MAIN EXTENSIONS DESIGN REPORTS FOR: GLEN LAKE SUBDIVISION BOZEMAN, MT Prepared By: MADISON ENGINEERING Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 APRIL 2018 WATER & SEWER MAIN EXTENSIONS DESIGN REPORTS FOR: GLEN LAKE SUBDIVISION BOZEMAN, MT a o CHiS G. • No. 10�5 PE • «r r O • 1✓/ •cEN��. Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 APRIL 2018 Water Report GLEN LAKE SUBDIVISION WATER SYSTEM DESIGN REPORT A. General This design report will give an overview of the proposed water main extension for the development of Glen Lake Subdivision in Bozeman. Improvements are anticipated to be constructed during the summer of 2018. Once the water main is constructed and approved, the main will become a part of the City of Bozeman system. Soil conditions on site include Turner Loam (457A) and Urban Land (UL). The Turner Loam is moderately wet,with 0 to 2 percent slopes, comprised of alluvium on stream terraces. The typical provide includes Loam in the upper 6 inches of the profile, followed by clay loams to depths of 26 inches, underlain by gravelly loam sand to depths of 60 inches. The soils are considered well drained and are included in hydrologic Soil Group B. There are three piezometers on the property from previous investigations of the site that were used to determine groundwater depth. No groundwater was identified in the piezometers at depths up to 9 feet during periods of normally high groundwater. Per the Slagle groundwater map, the groundwater is flowing in a westerly direction. 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. The following information was obtained by the City of Bozeman on April 10, 2018. Fire Hydrants— 1215 and 1216 Static Pressure, Ps: 140 psi Pitot Pressure, Pt: 102 psi Residual pressure, P,: 128 psi Hydrant discharge during testing, Qr,= 1,695 gpm, 2.5"port Distribution Main Capacity—Fire flow at minimum residual pressure Fire Flow at Residual Pressure, Qr= Qt[(Ps—Pr)/(Ps—Pt)]0.54 Qr= 1,695[(140—20)/(140— 102)]0.54 =3,154 gpm Glen Lake Subdivision Water Design Report Page I of 3 Qt= Hydrant Discharge during Test Qr= Fire Flow at Residual Pressure PS= Static Pressure P,,, = Minimum Residual Pressure = 20 psi Pr= Residual Pressure Pt= Pitot Pressure B. Proposed Water System The proposed water main extension consists of approximately 831 linear feet of 8" ductile iron along Brewery Dr that will connect to the existing 10" water main in Manley Rd in two (2) locations. C. Capacity Analysis The Glen Lake Subdivision water main extension is proposed for the development for the Glen Lake Subdivision, which includes 5.49 acres of M-1 (Light Manufacturing)zoning. An estimation of the water flow rate was based on wastewater flow calculations. The City of Bozeman design standards and specification policy's Table V-1 suggests using 980 gallons/acre/day for wastewater flows from a light manufacturing, M-1, district. Applying this value to a 5.49 acre parcel: 980 gallons 5.49 acres * acre = 5,380 gpd day Based on these parameters, the 5.49 acre development, at full build out, will have an estimated water usage of 5,380 gal/day, or an average daily demand of 11 gpm,based on an 8-hour day. 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 calculation below shows the water main extension has been designed to meet the maximum day demand plus fire flow during the peak hour. 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 11 gpm. TABLE 2 PEAKING FACTORS Flow Designation Peaking Factor Flow m Average Day Demand 1 11 Maximum Day Demand 2.3 25 Maximum Hour Demand 3 33 Glen Lake Subdivision Water Design Report Page 2 of 3 Based on communications with the architect, the maximum square footage of a building will be 2,500 sf(5,000 sf duplex split into two with appropriate separation). The front lot (Manley Rd frontage) units are a mix of R-1 and F-1. The back (Brewery Dr) units are F-1. All units will be a 2-hour V-A type construction without fire sprinklers. A Type V-A 2,500 sf building requires 1,500 gpm per the 2015 International Fire Code, Table B 105.1(2). 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 33 gpm, a maximum hour flow of 1,533 gpm is required. Flow analysis shows that an 8-inch DI pipe with a C value of 130 can provide 1,533 gpm with a pressure drop of 10.65 psi from 140 psi to 129.35 psi, above the minimum of 20 psi. The pipe velocity is 9.78m ft/s. This is a conservative analysis based on a dead end line,however this line will be looped into the existing main and served from both ends. D. Conclusion Based on this analysis, the proposed 8-inch Brewery Drive water main extension for the development of the Glen Lake 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. Glen Lake Subdivision Water Design Report Page 3 of 3 Sewer Report GLEN LAKE SUBDIVISION SEWER MAIN EXTENSION REPORT A. General Project Description This report will give an overview of the proposed wastewater collection system for the development of the Glen Lake Commerce Subdivision. The subdivision at legal description S31, TO S, R06 E, Lot IA, Glen Lake Annex to Bozeman. The zoning for the 15-lot, 5.49 acre area is currently listed as M-1, which is a light manufacturing district and small commercial area. The proposed development is anticipated to be constructed during the summer of 2018 and is located in Bozeman on the northeast corner of Manley Road and Griffin Drive. Included in this report is a description of the proposed wastewater collection system and design parameters. Once the wastewater system is constructed and approved, the system will become a part of the City of Bozeman system. The following references were used in the wastewater facilities design and capacity analysis: a. COB Design Standards and Specifications Policy, 2017. Addendum#6 b. COB Modification to Montana Public Works Standard Specifications(MPWSS) c. City adopted MPWSS and adopted Addenda d. COB Wastewater Facility Plan, 2017 e. WQB Circular No. 2 f. City of Bozeman Zoning Map The procedures and parameters outlined in the COB Design Standards and Specifications Guide were used in the design of the sewer infrastructure for the proposed development. B. Capacity Analysis The effluent generated from the proposed subdivision will be collected by one 8-inch sanitary sewer main along Brewery Drive. This 8-inch sewer main will flow northeastward into an existing manhole in Manley Road and flows northward in an existing 10" sewer main. The wastewater demands from the proposed subdivision were estimated based on a per acre basis for zoned areas. The density per zoned areas were obtained from Table V-1 of the City of Bozeman Design Standards and Specifications. Glen Lake Subdivision, consists of 5.49 acres of M-l(light manufacturing). The City of Bozeman's Design Standards specify an average daily flow rate of 960 gal/acre/day for M-1 development. The proposed sewer mains have been sized to flow at no more than 75-percent of full capacity at peak hour conditions of full build out, and a Manning coefficient of 0.013 was used for PVC pipe. Glen Lake Subdivision Wastewater Design Report Page 1 of 3 Glen Lake Subdivision The average daily flow based on the estimated wastewater flows is: (5.49 acres* 960 gal /day) = 5,270 gpd acre Using this daily flow rate, an approximate population of the subdivision can be approximated by using the City of Bozeman's average daily usage of 170 gpd/person. 5,270 gpd gpd = 31 persons 170 person This equivalent population can be utilized to determine a"peaking factor: Q _ 18 + P.5 _ 18 +.031.5 = 4.35 Al. 4+ P 5 4+.0315 (P=Population/thousands) Based on a total population of 31 people, a peaking factor of 4.35 was calculated. The calculated peaking factor is included in the appendix of this report. The peak flow rate anticipated from the development based on an average daily flow of 5,270 gallons per day is: Peak Flow Rate=(5,270 gpd x 4.35) =22,935gpd =48 gpm (based on an 8 hour day) = 0.11 cfs The sewer main size for the development will be an 8-inch, based on minimum required pipe size and slope. An 8-inch PVC sewer main at 0.40% slope has a capacity of 0.64 cfs at 3/ pipe depth which has adequate capacity for the proposed peak flow of 0.11 cfs effluent generated from the site. Calculations are provided in the appendix of this report. C. Proposed Collection System PVC pipe meeting COB specifications will be used for the sewer mains. The effluent from the Glen Lake Subdivision lots will drain into a proposed 8-inch diameter sanitary sewer main via 4- inch services. The effluent in the 8-inch will then flow northwestward into an existing 20-inch sewer main in Manley Road. The maximum manhole spacing will be 400 feet maximum for the 8-inch main. Manholes will be constructed according to COB specifications. All sewer services will be 4-inch PVC minimum installed at 2% minimum grade. Sewer services will connect into the main with in-line gasketed wyes. A 4-inch sewer service with a grade of 2.0% can convey Glen Lake Subdivision Wastewater Design Report Page 2 of 3 approximately 60 gpm at 50% capacity. The sewer main will maintain a minimum separation of 10-feet horizontally and 18-inches vertically from any proposed or existing public water mains. D. Downstream Capacity Analysis The sanitary sewer mains were designed in conformance with the City of Bozeman Wastewater Improvement Plan. It is anticipated that the City of Bozeman sanitary sewer system has enough capacity to accommodate the main extension. A capacity letter from a City Engineer will be required prior to DEQ approval of the system. E. Conclusion As outlined above, one single 8-inch sanitary sewer main serving the Glen Lake Subdivision has the capacity for the effluent generated from the subdivision. Also, the sanitary sewer main in Manley Road was sized in accordance with the Wastewater Collection Facilities Plan Update dated May 2015. This project will require the approval of the City Engineer and MDEQ. Appendix 1. Wastewater Main Capacity Analysis Glen Lake Subdivision Wastewater Design Report Page 3 of 3 Appendix 1: Sanitary Sewer Capacity Calculations 8-Inch PVC P100_Capaclty Projeot Desodptlon Fddlon Method Manning Formula Solve For Discharge Input Data Rmvhnese CoefacW 0.013 Channel Slops 0A00W % Normal Depth 5.55 In Diameter 8.00 In Results a.oharge 0.54 felt Flow Ms 0.28 SY WWtadPedmirlar 1.32 ft Hydraulic Radius L37 In Top Wkkh 0.01 A Critical Depth 0.38 A Pewt Full 09•8 % Craw Slope 0.017748 fbM Veb* 2A5 We yelapt Need 0.09 A SpeaftEherpy 0.58 A Frauds Number 0.66 Modmum Discharge 0.82 Vft Dlechatne Full 0.76 RW slope Fug 0.00276 Ant Flay Type SubMical OVF Input Data Downetroam Depth 0.00 In length 0.00 A Number Ot Slaps 0 OVF Output Data Upstream Depth 0.00 In Pro01e Desor"an Prollls Headbas 0.00 A Avenge End Depth Over Rlse 0.00 % Normal Depth Over Rba so-To % Dowrrinam Velocity Ifftily Ale ■anVay 8yalema,Ina IYeshd Methods Yal(1101.ECDOP1041) (Oe.11.01.031 411112019 9:20:06 AM V Blew.Cow4wT Drlre ielle=0 W Wideftwo,CTOeraa UM#14W-7064ae0 Pap I or 2