4000

• UCREFRP Catalog Number: 4000
• Author: U.S. Department of the Interior.
• Title: Report on Water For Energy in the Upper Colorado River Basin.
• USFW Year: 1974.
• USFW - Doc Type: \
• Copyright Material: NO

for the particular set of assumptions mentioned above. Other
combinations of assumptions, particularly those associated with
downstream deliveries; period of years used for water supply
and system operation; future condition of reservoirs due to
sediment accumulation; the distribution of uses - i.e.,
irrigation, industrial or export; and the future year to
which uses are projected would alter the total water available.
Reduction of releases to the Lower Basin below 8.25 million
acre-feet would increase the level of available water for use
in the Upper Basin by far the greatest amount. Other hypotheses
could either increase or decrease the available supply by a
smaller but substantial annual amount.

2. Water Supplies of the Colorado River., 196~/ - An engineering
consultant's study performed for the Upper Colorado River
Commission determined that 6.3 million acre-feet would be
available for consumptive use if 7.5 million acre-feet only
were delivered to the Lower Basin and no shortages were
required of Upper Basin users. These two conditions alone
cause a substantial difference from the minimum assured
supply derived in the Department's study described above.
If this variation in assumptions is taken into account, the
results of the two studies are essentially the same. Many
changes in development plans have occurred since these studies
were made and will continue to occur as priorities shift and
technological advances ~volve.

Present Consumptive Utilization - The present (1974) level of depletions
from the Upper Colorado River system above Lee Ferry total 3,187,000
acre-feet. Main stem reservoir evaporation was computed to be 520,000
acre-feet, so the present utilization totals 3,707,000 acre-feet.
Depletions include all of the average annual man-caused on-site
uses within the Upper Basin for agriculture, municipal, industrial,
fish and wildlife, recreation, and net export of water above Lee Ferry
together with evaporation from reservoirs associated with these
functions. These depletions do not include on-site use of surface
and subsurface water on public lands which is used thropgh management
of natural resource programs.

Depletions estimated for each State based on normal operations for
1974, and main stem evaporation are presented in Table 1. Evaporation
was distributed to each of the States by the same percentages provided

1/ Prepared by Tipton and Kalmback, Inc., Denver, Colorado, July 1965.

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