HomeMy WebLinkAboutWater&SewerDemandCertification DESIGN REPORT
WATER AND SANITARY SEWER
DEMAND CALCULATIONS
LOTS 2 -3, BLOCK 2
GLEN LAKE COMMERCE SUBDIVISION
Prepared for:
JBRC, Inc.
Jim@jrothgeb.com
(818)-636-4823
Prepared by:
Engineering and Surveying Inc.
1091 Stoneridge Drive • Bozeman, MT 59718
Phone (406) 587-1115 • Fax [406) 587-9768
www.chengineers.com • info@chengineers.com
May 2021
r eat'' e erg
C&H Project No. 210418
INTRODUCTION
The proposed building with seven residential/shop units is located on Lots 2 - 4, Block 2 of Glen
Lake Commerce Subdivision in Bozeman, Montana. The project includes construction of (4)
live/work apartment buildings with 16 total units.
The property is fronted on two sides by City streets with Manley Road and Iron Horse Road being
adjacent to the east and west property boundaries, respectively. Water and sanitary sewer mains
are located within Iron Horse Road and individual water, fire, and sanitary sewer services will
connect to each of the proposed buildings 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 = 2.17 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 (16 dwelling units)
Average Day Demand= 16 d.u. x 2.17 persons/d.u. x 170 gpcpd= 5,902 gpd=4.10 gpm
Maximum Day Demand =4.10 gpm x 2.3 = 9.43 gpm
Peak Hour Demand =4.10 gpm x 3.0 = 12.30 gpm
Design Report-Page 2 of 3
Sanitary Sewer Design Load
The population estimates of 2.17 people per dwelling unit, and residential flow rate of 64.4 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 2.17 persons per household the equivalent population is calculated.
Connection:
Equivalent Population =(2.17 persons/dwelling unit)(16 units) = 34.72 persons
Harmon Formula: Peaking Factor= (18 +P0-5)/(4 +P0-5)
where: P =Population in thousands
Peaking Factor= (18 + 0.0350-5)/(4 + 0.035-5)
Peaking Factor=4.34
Assumed infiltration rate = 150 gallons/acre/day= 150 (1.057 acres)= 159 gal/day
The peak flow rate is calculated by multiplying the City's design generation rate of 64.4 gallons per
capita per day by the population,multiplying by the peaking factor,and adding the infiltration rate:
Peak Flow Rate = 64.4 gpcpd (34.72 persons) (4.34) + 159 gpd = 9,863 gpd
6.85 gpm
0.018 cfs
Design Report-Page 3 of 3