Loading...
HomeMy WebLinkAbout20 - Design Report - Icon Homes at Ferguson Farm - Water, Sewer WATER & SEWER DESIGN REPORT FOR: ICON HOMES AT FERGUSON FARM INFRASTRUCTURE IMPROVEMENTS BOZEMAN, MT Prepared By: MADISON ENGINEERING Madison Engineering 895 Technology Drive, Suite 203 Bozeman, MT 59718 (406) 586-0262 OCTOBER 2020 WATER MAIN DESIGN REPORT FOR: ICON HOMES AT FERGUSON FARM INFRASTRUCTURE IMPVOREMENTS BOZEMAN, MT �*%%I ITA e ri JS G. e CUD[S i Sa E ' ,SIONA,����r . Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 OCTOBER 2020 ICON HOMES FERGUSON FARM INFRASTRUCTURE IMPROVEMENTS WATER SYSTEM DESIGN REPORT A. General Project Description This design report will give an overview of the proposed water main extension for the development of Icon Homes Infrastructure Improvements. The proposed improvements are anticipated to be constructed during the Winter of 2020. 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 located within West Babcock existing 12"water main and the existing 8" water main within the current development. The following information was obtained from the City of Bozeman: Hydrant ID#: 1550 Maximum Day Demand Minimum Pressure: 21.20 psi Maximum Day Demand Average Pressure: 46.32 psi Maximum Day Demand Maximum Pressure: 67.91 psi Maximum Day Demand Available Fire Flow at 20 psi: 4,600 gpm Hydrant ID#: 1754 Maximum Day Demand Minimum Pressure: 20.92 psi Maximum Day Demand Average Pressure: 73.74 psi Maximum Day Demand Maximum Pressure: 121.13 psi Maximum Day Demand Available Fire Flow at 20 psi: 8,000 gpm The two hydrants listed above were used to create a three-point pump curve to model the existing connections to the City system. The first point uses the static pressure of the system when the flow is equal to zero. The second point uses the maximum day demand available fire flow at 20 psi (given above). The third point was determined by selecting an arbitrary pressure between the static pressure and the minimum pressure of 20 psi. An example calculation for Hydrant ID #1550 is given below: Icon Homes Phase II Infrastructure Improvements Water Design Report Page 1 of 3 Q,= Qt[(Ps—Pm)/(Ps—P01 0.54 Q,=4,600 [(67.91 —46.32)/(67.91 —21.20)]0.54 Q, = 3,032 gpm at 46.32 psi Qt= Maximum Day Demand Available Fire Flow @ 20 psi Qr= Fire Flow at Desired Fire Flow Residual Pressure Ps= Static Pressure Pm = Desired Residual Pressure =46.32 psi Pr= Minimum Residual Pressure =21.20 psi B. Proposed Water System The proposed water main extension for Icon Homes Phase 2 consists of approximately 910 linear feet of 8" ductile iron pipe that will connect to the existing water main within West Babcock via tapping tee and the existing cap and blowoff assembly within the development. The layout of the proposed water main meets the COB design criteria and will be located within a 30' foot wide public utility easement 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 Icon Homes water main extension is proposed for the multiphase development of 6 buildings. The proposed project consists of a comprised total of 120-units (10 — 3 Bedroom Units, 64 — 2 Bedroom Units, 46 — 1 Bedroom Units), which sits on a 6.14 acre 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 units in each phase the required water flow rate is calculated: Phase II—Full Build out residents gallons (120 units * 2.11 * 170 day) = 43,044 gpd unit capita Based on these parameters,the phased development will have an estimated water usage of 43,044 gpd (29.89 gpm) at full build out. 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. Icon Homes Phase 11 Infrastructure Improvements Water Design Report Page 2 of 3 TABLE 1 PEAKING FACTORS Flow Designation Peaking Factor Flow (gpm) Average Day Demand 1 29.89 Maximum Day Demand 2.3 68.75 Maximum Hour Demand 3 89.67 Three types of buildings will be constructed and will consist of 4— 12 Plexes, 2—20 Plex and 1 — 32 Plex for a total of 7 individual buildings. The square footage for each type of building are as follows: 12 Plex= 17,792 sf, 20 Plex=27,773 sf& 32 Plex =44,858 sf. Based off communication with th architect, the units are expected to be type V-A construction with fire sprinklers. The largest building based of square footages was choosen for a more conservative analysis. A Type V-A 44,858 sf building requires 1,500 gpm for a 3-hour flow duration per the 2015 International Fire Code, Table B 105.1(2). Results Based on the analysis outlined above, the required minimum fire flow is 1,500 gpm and the maximum hour demand is 89.67 gpm. The maximum hour demand was distributed throughout each water service within the subdivision. 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 where a building has a potential fire flow demand in addition to all hydrants. The flow analysis shows that an 8-inch DI pipe can provide the development with the required flow of 1,500 gpm in addition to the peak hour demand and remain above the minimum pressure of 20 psi. The maximum velocity within the water mains was constrained to 15 ft. per second per City of Bozeman specifications. See attached flow analysis for calculations. D. Conclusion Based on this analysis, the proposed 8-inch ductile iron water main extension serving the Icon Homes Phase II residential office development provides adequate service to meet the 120-unit peak hour demand and fire flow requirements for the development. 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. Icon Homes Phase II Infrastructure Improvements Water Design Report Page 3 of 3 Page 1 of 1 Scenario: Automated Fire Flow Analysis Current Time Step: 0.000 h Fire Flow Node FlexTable: Fire Flow Report Fire Flow Fire Flow Flow(Total Flow(Total Pressure Junction w/ Velocity of Pipe w/ Label (Needed) (Available) Needed) Available) (Calculated Minimum Maximum Maximum (gpm) (gpm) (gpm) (gpm) Residual) Pressure Pipe(ft/s) Velocity (psi) (Zone) J-3 1,500 2,260 1,500 2,260 91 J-26 15.00 P-15 J-12 1,500 2,260 1,500 2,260 97 J-35 15.00 P-15 J-5 1,500 2,260 1,500 2,260 87 J-26 15.00 P-15 J-15 1,500 2,260 1,500 2,260 87 J-26 15.00 P-15 J-7 1,500 2,260 1,500 2,260 95 J-26 15.00 P-16 J-16 1,500 2,260 1,500 2,260 100 J-35 15.00 P-16 J-10 1,500 2,260 1,500 2,260 104 J-35 15.00 P-15 J-13 1,500 2,260 1,500 2,260 83 J-34 15.00 P-16 J-18 1.500 2,260 1 1.500 2,260 86 J-34 15.00 P-15 GAACAD\2019\19-113 Icon Apts PH II\dwg\Civil\WaterCad\Icon Apts. Phase II WaterCAD.wtg file:///C:/Users/Tech7/AppData/Local/Temp/Bentley/WaterCAD/ba5mxzyd.xml 9/9/2020 Scenario: Automated Fire Flow Analysis w .n y yr r d LO o 4.0 a 6A U 01W N M SEWER MAIN DESIGN REPORT FOR: ICON HOMES AT FERGUSON FARM INFRASTRUCTURE I PROVEMENTS BOZEMAN, MT O .• CiC►il15 G. I,-- BUT r BUD .� Cc IlL5 Pc ; uJ= 'L .. e-K;/6 CENS.11 NA+oils Madison Engineering 895 Technology Blvd Ste 203 Bozeman, MT 59718 (406) 586-0262 OCTOBER 2020 ICON HOMES AT FERGUSON FARM INFRASTRUCTURE IMPVORMENTS SEWER SYSTEM DESIGN REPORT A. General Project Description This design report will give an overview of the proposed wastewater collection system for the development of Icon Homes Infrastructure Improvements Phase 1I. The proposed improvements are located South of West Babcock and West of Resort Drive in Bozeman, MT. The zoning for the 6.14-acre area is listed as R-O, residential office district. The proposed buildings are designed as four (4)twelve-plex buildings, two (2)twenty-plex buildings and one (1) thirty-two— plex building for a total of 7 individual buildings and a total of 120 units in the development. The infrastructure improvements for development are anticipated to be constructed during the winter of 2020. 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(C.O.B.) 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. Proposed Sewer System (Capacity Analysis) The proposed wastewater collection system consists of 381 linear feet of new 8"PVC sewer main and will provide service to the proposed development. The effluent generated from the proposed buildings will be collected by the wastewater collection system and ultimately flow West to the existing COB Manhole located within the current site. The wastewater demands from the proposed development were estimated based on a flow per capita basis, which provided a more conservative flow than a per zoned acre basis. (COB Table V-1 specifies an average daily flow rate of 980 gal/ac-day for R-O zoning, resulting in 6,017 gpd = 6.14 ac x 980 gal/ac-day). The proposed sewer main has 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. Icon Homes Phase II Infrastructure Improvements Wastewater Design Report Page ] of 3 The average daily flow is based on the number of units, 2.11 residents per unit, and 89 gallons per capita per day, the latter two values based on COB design standards: ( residents * 89 gallons l _120 units * 2.11 unit capita/day I 22,535 gpd An approximate population for Icon Homes phase B development at full build out is calculated as: residents 120 units * 2.11 = 254 persons unit This is a more realistic population value compared to utilizing the 5.2 units per acre (Table V-1 from COB design standards) applied to 6.14 acres, which only results in 32 persons. This equivalent population can be utilized to determine a peaking factor: (Q _ 18 + P•5 18 +.254.5 71ux _ = 4.11 \QAve 4 + p.5 4 +. 254-` (P =Population/thousands) Based on a total population of 254 people, a peaking factor of 4.11 was calculated. The peak flow rate anticipated from the development based on an average daily flow of 22,535 gallons per day is: Peak Flow Rate = (22,535 gpd x 4.11) = 92,619 gpd = 64 gpm = 0.14 cfs Additionally, an infiltration flow of 921 gpd(150 gal/acre/day x 6.14 acres)has been added to the flow, resulting in a total flow of 93,540 gpd (0.144 cfs). The sewer main size for the development will be an 8-inch, based on minimum required pipe size and designed at a 0.45% slope,which is above the city required minimum slope of a 0.40%. An fl- inch PVC sewer main at 0.40%slope has a capacity of 0.64 cfs at 3/4 pipe depth,which has adequate capacity for the proposed peak flow of 0.144 cfs effluent generated from the site. Calculations are included in the end of this report. C. Proposed Collection System PVC pipe meeting COB specifications will be used for the sewer mains. The effluent from the Icon Homes Phase 1I development will drain into a proposed 8-inch diameter sanitary sewer main via 6-inch sewer services. The effluent in the 8-inch wastewater collection system within the site will flow to the West to the existing C.O.B. manhole already located within phase 11. The Icon Homes Phase II Infrastructure Improvements Wastewater Design Report Page 2 of 3 maximum manhole spacing will be 400 feet for the 8-inch main. Manholes will be constructed according to COB specifications. Sewer services will be 6-inch PVC installed at 1% minimum grade. Sewer services will connect into the main with in-line gasketed wyes. 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 as this was included in the onsite design of the downstream collection system. A capacity letter from a City Engineer will be required prior to DEQ approval of the system. E. Conclusion As outlined above, a proposed 8-inch sanitary sewer collection system serving the residential development has the capacity for the effluent generated from the subdivision. The wastewater sewer collection system was designed on a conservative premise for future development. This project will require the approval of the City of Bozeman Engineer and MDEQ. Icon Homes Phase II Infrastructure Improvements Wastewater Design Report Page 3 of 3 8-Inch PVC Pipe Capacity__ Project Description Friction Method Manning Formula Solve For Discharge Input Dale Roughness Coefficient 0.013 Channel Slope 0.40000 % Normal Depth 5.58 In Diameter 8.00 in Results Discharge 0.64 Wis Flow Area 0.26 fN Welled Perimeter 1.32 ft Hydraulic Radius 2.37 in Top Width 0.61 ft Critical Depth 0.36 ft Percent Full 69.8 % (93%full flow capacity x 75%flow depth) Critical Slope 0.00748 ftM Velocity 2.45 ft/s Velocity Head 0.09 ft Specific Energy 0.56 fl Froude Number 0.66 Maximum Discharge 0.82 fN/s Discharge Full 0.76 fP/s Slope Full O.D0278 ft/ft Flow Type SubCrftloaf GVF Input Data Downstream Depth 0.01) In Length 0.00 1t Number Of Steps 0 GVF Output Data Upstream Depth 0.00 In Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 Normal Depth Over Rise 69.76 % Downstream Velocity Infinity f/s Bentley Systems,Inc. Neastad Methods 8oletmllipffi evMseter Vill(SELECTaeries 11 [06.11.01.031 4111/2016 0:20:06 AM 27 Slemons Company Drive Sulte 200 W Watertown,CT 09795 USA +1-203-766.1666 Page 1 of 2