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TruNorth Center
Water Design Report
TruNorth Center
Water System Demand Report
Summary
This report outlines the water daily flow analysis calculations for the proposed TruNorth Center
Development. The Master Site Plan water report did not account for the water demands for this
site. The City will review the water demands calculated in this report and evaluate the adjacent
system’s capacity to accommodate the estimated demands.
Proposed Project Demand
The proposed TruNorth Center consists of two buildings, an office building (1340 E. Main St)
and a coffee/donut shop (1342 E. Main St). The future office building is an 11,626 SF two-story
structure with a max occupancy of 78. Based on a conservative basis the office building will use
0.273 gpd/sf, per water supply planning book by David W. Prasifka. Taking these factors into
consideration the office building contributes:
(0.273 gallons per day
square feet ∗11,626 square feet)=𝟑,𝟏𝟕𝟑 𝐠𝐩𝐝
The future Alza coffee/donut shop is a 5,148 SF three-floor structure with a max occupancy of
128. Based on a conservative basis the office building will use 41 gpd/seat, per water supply
planning book by David W. Prasifka. Taking these factors into consideration the coffee/donut
contribute:
(41 gallons per day
seat ∗128 seats)=𝟑,𝟏𝟗𝟕 𝐠𝐩𝐝
The addition of these two structures amounts to an average daily flow of 8,371 gpd or 5.8 gpm.
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 of 5.8 gpm.
TruNorth Center
Water Design Report
TABLE 1
PEAKING FACTORS
Flow Designation Peaking Factor Flow (gpm)
Average Day Demand 1 5.8
Maximum Day Demand 2.3 13.34
Maximum Hour
Demand 3 17.4
Both buildings will be outfitted with a fire protection system with a minimum fire flow of 1,500
gpm. With the addition of the fire suppression system, the maximum hour flow demand is 1,517.4
gpm.
This project will require the approval of the City of Bozeman Engineer and MDEQ.
Daily Water Usage Analysis
TruNorth Center
Average Daily Flow
Building Area
TruNorth Office Building 11626 sq. ft.
Annual Water Use/sq. ft.0.273 gpd/sq. ft.
Average Daily Flow 3,174 gpd
Max. Occupancy
Alza Building 128 occupancy
Annual Water Use/seat 41 gpd/seat
Average Daily Flow 5,197 gpd
Total Annual Water Use 8,371 gpd
Peaking Factor Calculations
Max Occupancy
78.00
128.00
206.00
=Q(max)= 18 + P
0.50 P = Population/thousands = 206/1000 = 0.206
Q(ave)4 + P
0.50
Peaking Factor =
Peak Hour Water Usage
Average Daily Usage 8,371 gpd
Maximum Hour Usage 25,112 gpd
Maximum Hour Usage 1046.3 gph
Maximum Hour Usage 17.4 gpm
Minimum Fire Flow Usage 1500.0 gpm
Total Max. Hour Usage 1517.4 gpm
4.61
Peaking
Factor
Tru North Office Building
Alza Building
Total Population