WSP11534

• File Number: 8270.100
• Description: Colorado River Basin Water Quality/Salinity -- Misc Water Quality
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1991
• Author: USDOI
• Title: Quality of Water - Colorado River Basin - Progress Report No. 15 - January 1991
• Water Supply Pro - Doc Type: Report/Study

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Chapter 6

Present and Future Development

This section of the report llummarizes the project
depletions used by the Colorado River
Simulation System (CRSS) to estimate the
effect8 of depletions by water resources
development at selected stations within the
basin. Chapter 8 summarizes the results of the
computer modeling.

Table 3 presents a summary of the estimated
depletion of water through the year 2010 for
both the Upper and Lower Basins of the
Colorado River. Depletions for 1990 were
estimated in 1989 for preparing this report. The
projections for the years 1990 through 2010
represent the best estimate by the Bureau of
Reclamation oEhow water use will be developed
over the next 20 years. The projections were
made after consultation with individual States
within the Colorado River Basin; however, the
States do not necessarily concur with the
projections adopted by Reclamation for planning
purposes.

UPPER BASIN DEPLETIONS

Table 3 summarizes estimates of depletions due
to water development in the Upper Colorado
River Basin. Reclamation made these estimates
in consultation with the water resource agencies
of the Upper Basin States, and they have been
reviewed by the St:'ltc'S.

Estimates of use in 1990 were developed by
updating depletions reported in the Upper
Colorado Region Comprehensive Framework
Study published in June 1971. Projections of
water use beyond 1990 were developed from
information supplied by State water resource
agencies and from construction schedules of
projects authorized for construction or already
under construction.

In table 3, the entry under each State labeled
"'Evaporation, Storage Units- represents that
State's share of total evaporation from Flaming

Gorge Reservoir, Lake Powell, and the Aspinall
Unit Reservoirs which will be charged to that
State when total Upper Basin water develop.
ment is reached. This is provided for in
Article V of the Upper Colorado River Basin
Compact.

The Upper Colorado River Basin Compact
provides that the Slates of Arizona, Colorado,
New Mexico, Utah, and Wyoming will share in
the consumptive use of water available in the
Upper Basin in the following proportions:
Arizona, 50,000 acre.feet; Colorado,
51.75 percent of remainder; New Mexico,
11.25 percent of the remainder; Utah,
23.00 percent of the remainder; and Wyoming,
14.00 percent of the remainder.

Arizona

Miscellaneous Additional Depletions

Consumptive uses due to irrigation and
stock pond evaporation have increased by about
6,000 acre-feet since the Comprehensive
Framework Study estimates were prepared.
Municipal and domestic uses have increased by
about 6,000 acre-feet. The Navajo Indian Nation
and the city of Page, Arizona, are expected to
use an additional 6,000 acre-feet for municipal
purposes. Water for Page is reserved by The
Reclamation Development Act of 1974, Public
Law 93-493, which, among other actions,
provided for the incorporation of the city.

Navajo Powerplant

Consumptive uses, according to records provided
by the Nav~o Generating Station, averaged
22,000 acre. feet over the 1980-85 period. The
contract for sale of water out of Lake Powell
allows for annual uses of up to 34,100 acre.feet;