WSP07539

• File Number: 8281.300
• Description: Colorado River Studies and Investigations - Colorado River Consumptive Uses and Losses Report
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1991
• Title: Consumptive Uses and Losses in the Arizona Portion of the Upper Colorado River Basin for the Water Year 1990
• Water Supply Pro - Doc Type: Report/Study

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Consumptive Uses and Losses

4

use; reservoir and stock pond evaporation losses, about 8 percent; municipal
and domestic consumption, about 20 percent; and livestock consumption,
4 percent.

INDUSTRIAL CONSUMPTIVE USE

The water used by the NGS is pumped directly from Lake Powell and
comprises over half of the total consumption in the study area. Since all
NGS water use is metered, this quantity is among those most precisely known,
with the maximum uncertainty in the metered quantities believed to be less
than 3 percent. The actual quantity consumed, along with the estimated
uncertainty for the water year 1990, was 20,720 (:t620) acre-feet.

Industrial consumption is expected to grow during the years 1997-1999, due to
antipollution "scrubbers" being installed on the exhaust stacks increasing water
use by 1,000 acre-feet per year for a total increase of 3,000 acre-feet in 1999.

MUNICIPAL AND DOMESTIC CONSUMPTIVE USE

City of Page

The city of Page pumps its domestic water, which amounts to about 6 percent of
the total use within the study area, directly from Lake Powell. The water
pumped is metered, and the uncertainty of the pumped quantities was assumed
to be less than 3 percent. The quantity pumped and its associated uncertainty
for the water year 1990 was 2,060 (:t60) acre-feet. The waste water for the city
of Page is treated and is either evaporated from lined ponds or applied to the
golf course and other parks or lawns. Water returning to the waste water
treatment plant is metered as well. In the past, the difference between the
amount of water pumped from Lake Powell and the sum of the evaporation and
consumptive use of water used for lawns showed that over half of the water
pumped was unaccounted for, some of which can be attributed to deep
percolation.s As it is not known how much water actually goes to deep
percolation, all unaccounted for water was assumed lost to the system.

3 Ron Ewing, a private consultant for the city of Page, stated that there is considerable lawn
and g~rden irrigation directly from the city water supply. He estimated that about 500 gallons
per capita per day ie being pumped during the summer months, while about 135 gallons per
capita per day is being returned to the waste water treatment plant. Due to the sandy soils in
the area, a certain amount of overinigation occurs. A considerable amount of municipal water
appears to be return flow to the Colorado River System. It has been recommended that studies
be done to estimate the amount of return flows that are accuning in this area, as the city of Page
would be credited for those. However, in this report all water pumped from Lake Powell for the
city of Page will be counted as losses to the system, as no information concerning return flows is
available.