HomeMy WebLinkAbout19--Water Design Report_SignedWater Design Report
Lot 5, Block 16, Baxter Meadows Subdivision Phase 2A
Bozeman, MT
109 E. MAIN STREET, BOZEMAN, MT 59715 I OFFICE 406.728.4611 I EMAIL wgm@wgmgroup.com
Water Design Report
REPORT DATE:
August 2022
AUTHOR:
Gary Fox, P.E.
Project Engineer
WGM Group, Inc.
Water Design Report
CONTENTS
1.0 INTRODUCTION AND PROJECT DESCRIPTION ............................ 2
2.0 WATER SYSTEM ANALYSIS............................................................ 3
1.0 INTRODUCTION AND PROJECT
DESCRIPTION
The proposed project is a mixed-use development north of Equestrian Lane and east of Vaquero Parkway
in Bozeman, Montana. The site is 0.307 acres. City water infrastructure exists in Equestrian Lane on
the south side of the property. Below is an image from the City GIS website.
The project intends to connect to the existing water infrastructure alone Equestrian Lane, specifically
the existing 4-inch diameter water stub into the lot. The project plans to extends a new 2-inch diameter
water service line from the existing stub to the new building.
The proposed building consists of 2 residential units and 2 commercial units. Residential unit 1 is
planned to have 3 bedrooms and residential unit 2 is planned to have 2 bedrooms. Each residential
unit includes a kitchen. Total commercial area square footage is approximately 5,115. The commercial
area will include 4 bathrooms, one janitor room with a sink, and one laundry room. No fire service or
sprinklers are proposed.
Water Design Report
This design report summarizes the projected average, maximum day, and peak water demands for the
development.
2.0 WATER SYSTEM ANALYSIS
An average daily demand of 170 gallons per capita per day unit has been used per City of Bozeman
Design Standards and Specifications Policy.
Design Parameters:
Average daily use: 170 gallons/capita/day
Average Population Density: 2.11 persons/dwelling unit
Minimum Fire Hydrant Flow: 1,500 gpm
Residual Pressure Required: 20 psi for Fire Flow
Average Day Demand: Peaking Factor = 1.0
Maximum Day Demand: Peaking Factor = 2.3
Maximum Hour Demand: Peaking Factor = 3.0
Proposed Residential: 2 units (2.11 persons/DU)
Proposed Commercial: 2 units (equivalent population of 6 persons/DU assumed to be
conservative based on projected use and available parking)
Average residential demand: 170 gpcpd x 2 units x 2.11 persons/DU = 717 gpd = 0.5 gpm
Average commercial demand:170 gpcpd x 2 units x 6 persons/DU = 2,040 gpd = 1.4 gpm
Total Average Day Demand: 1.9 gpm (0.5 + 1.4)
Maximum Day Demand: (1.9 gpm x 2.3) = 4.37 gpm
Peak Hour Demand: (1.9 gpm x 3.0) = 5.7 gpm
As part of the project, the City of Bozeman sent WGM hydrant flow testing data for the nearest fire
hydrants east and west of the project. Those hydrants are numbers 2773 and 1956 respectively. The
adjacent mains are 8-inch (Vaquero) and 10-inch (Equestrian) diameter ductile iron. Hydrant flow curves
and available flow data is provided in this report.
Water Design Report
For hydrant 2773, the flow data is summarized as follows:
Static Pressure: 115 psi (pressure at 0 gpm flow)
Residual Pressure: 107 psi (at 1,500 gpm)
Flow Rates: 1500 gpm (minimum per City)
Note the available flow at a minimum residual pressure required (20 psi): ~11,500 gpm
Based on the results of the fire flow testing, along with the average, maximum, and peak hour demands
calculated above for the development, the existing City water system infrastructure is adequately sized
to handle this development. It is our understanding that the Baxter Subdivision water system was sized
according to the future projected use of the project site and adjacent lots. Also, based on a fixture county
analysis, the proposed 2-inch diameter water service is adequately sized for the development.
Water Design Report
Water Design Report