HomeMy WebLinkAbout014-water -sewer usage
1105 REEVES RD. W. STE 6
BOZEMAN, MT 59718
406-581-5730
www.headwatersmt.net
Page 1 of 1
BPCP Facility
Lot 12 of Plat J-300 of Gallatin Park Subdivision
Sanitary Sewer Usage
The proposed project includes one 18,605 sf indoor recreational facility and one 2,603 sf office on
approximately 2.01 acres. Average day residential flows were calculated using DEQ Tables 3.1-1 & 3.1-2. The
facility use likely ranges between 5 gallons per person (visitor center) and a Swimming Pool at 10 gallons per
person. At an average of 7.5 gallons per visitors and an estimated average day of 100 visitors per day. The
office building anticipates roughly 12 employees per day at 13 gallons per person.
Average Facility Daily Flowrate = (100 people) x (7.5 gpd/person) = 750 gpd
Average Office Daily Flowrate = (12 employees) x (13 gpd/person) = 156 gpd
Total Average Daily Sewer Flow = 906 gpd = 0.63 gpm
The total population of 113 people yielded a peaking factor of 4.22. The peaking factor, PF, was calculated by
the following formula, where P = population (thousands):
PF = 18 + P0.5
4 + P0.5
Using a peak hour factor of 4.22 was and adding the City’s infiltration allowance of 150 gallons per acre per day
resulted in a combined peak hourly flowrate of 27,015 gpd.
Peak Hourly Flowrate = ADF x PHF + 150 gpd/acre Peak Hourly Flowrate = 906 gpd x 4.22 + 150 gpd x 2.01 ac = 4,125 gpd = 2.86 gpm
Water Usage
The estimated water usage for the site was calculated utilizing a the sewer rates from DEQ discussed above
and then multiplying that by the City’s peaking factors. Using the City’s max day flow factor of 2.3, results in a
maximum daily demand of 2084 gpd. Multiplying the average daily flow by the City’s peak hour factor of 3,
results in a peak hour demand of 2718 gpd or 1.89 gpm. Local landscape watering is included in the empirical
data. The calculated daily irrigation water usage is 1020 gpd per the inContour Landscape Plan, this fits well
within the max hour flows of 2718 gpd.
Average Residential Daily Flowrate = 906 gpd
Maximum Daily Flowrate = ADF x 2.3 = 0.63 gpm x 2.3 = 1.45 gpm
Maximum Hour Flowrate = ADF x 3.0 = 0.63 gpm x 3.0 = 1.89 gpm
Calculations completed by Jeremy May, P.E.
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