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DESIGN REPORT
WATER AND SANITARY SEWER
DEMAND CALCULATIONS
TRACT 2A [PLAT F-1-D]
Prepared for:
Crater Mountain Investments, LLC
1906 Blanca Ct.
Loveland CO, 80538-5022
Prepared By:
1091 Stoneridge Drive • Bozeman, Montana • Phone (406) 587-1115 •
www.chengineers.com • E-Mail: info@chengineers.com
IMEG Project Number: 22003609
C&H Project Number: 210528
February 2023
Design Report - Page 2 of 3
INTRODUCTION
The Pines, Phase 2 Site Plan is a proposed apartment development located on Tract 2A of [Plat F-
1-D]. The proposed layout consists of one 12-unit apartment building, a drive access, a parking
area, and related stormwater and landscaping areas. The property is located within the City of
Bozeman limits and is currently zoned R-4.
The property is fronted on one side by South 19th Ave, water and sanitary sewer mains are located
within South 19th Ave. and water/sewer services are proposed to serve the development as shown
on civil sheet C2.1.
Water Distribution System Demands
The design parameters used herein are according to the City of Bozeman Design Standards and
Specifications Policy (DSSP) dated May 2017.
Average Daily Residential Usage = 170 gallons per capita per day
Average Population Density = 2.11 persons/dwelling unit
Average Day Demand (Peaking Factor = 1.0)
Maximum Day Demand (Peaking Factor = 2.3)
Peak Hour Demand (Peaking Factor = 3.0)
Water Demands (12 dwelling units)
Average Day Demand = 12 d.u. x 2.11 persons/d.u. x 170 gpcpd = 4,304 gpd = 2.99 gpm
Maximum Day Demand = 2.99 gpm x 2.3 = 6.88 gpm
Peak Hour Demand = 2.99 gpm x 3.0 = 8.97 gpm
Design Report - Page 3 of 3
Sanitary Sewer Design Load
The population estimates of 2.11 people per dwelling unit, and residential flow rate of 89 gpcd
used herein are according to the City of Bozeman Design Standards and Specifications. The
peaking factor for the design area is determined using the formula provided in the City of Bozeman
Design Standards and Specifications.
Using the city average of 2.11 persons per household the equivalent population is calculated.
Connection:
Equivalent Population = (2.11 persons/dwelling unit)(12 units) = 25.32 persons
Harmon Formula: Peaking Factor = (18 + P0.5)/(4 + P0.5)
where: P = Population in thousands
Peaking Factor = (18 + 0.025320.5)/(4 + 0.025320.5)
Peaking Factor = 4.366
Assumed infiltration rate = 150 gallons/acre/day = 150 (0.440 acres) = 66 gal/day
The peak flow rate is calculated by multiplying the City's design generation rate of 89 gallons per
capita per day by the population, multiplying by the peaking factor, and adding the infiltration rate:
Peak Flow Rate = 89 gpcpd (25.32 persons) (4.366) + 66 gpd = 9,905 gpd
= 6.88 gpm
= 0.015 cfs
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Demands.Docx