WSP04117

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1976
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1976 Projected Operations 1977
• Water Supply Pro - Doc Type: Publication

Proiected Plan of Operation
under Criteria for Current Year

View of Hoover Dam overlooking the roadway from
Nevada side.

Determination of "602(a) Storage"

Section 602(a)(3) of the Coiorado River Basin
Proiect Act of September 30, 1968 (Public Law
90-537), provides for the storage of Colorado River
water not required to be released under article
III(c) and III(d) of the Colorado River Compact in
Upper Basin reservoirs to the extent the Secretary
finds it to be reasonably necessary to assure Com-
pact deliveries without impairment of annual con-
sumptive uses in the Upper Basin. Article II of the
"Criteria for Coordinated Long-Range Operation
of Colorado River Reservoirs," pursuant to the
act, provides thai the annual plan of operation
shall inciude a determination by the Secretary of
the quantity of water considered necessary as of
September 30 of the current year to be in storage
as required by section 602(a) of Public Law 90-537
after consideration of all applicable laws and rele-
vant factors including, but not iimited to: (a) his-
toric streamflows; (b) the most critical period of
record: (c) probabiiities of water supply; (d) esti-
mated future depletions in the Upper Basin, in-
cluding the effects of recurrence of critical periOds
of water supply; (e) the "Report of the Committee
on Probabilities and Test Studies to the Task
Force on Operating Criteria for the Colorado
River," dated October 30, 1969, and such addi-
tional studies as the Secretary deems necessary;
(f} the necessity to assure that Upper Basin con-
sumptive uses are not impaired because of failure
to store sufficient water to asSUre deliveries under
section 602(a)(1) and (2) of Public Law 90-537,

26

Taking into consideration these and other reievant
factors, the Secretary has determined that the ac-
tive storage in Upper Basin reservoirs forecast for
September 30, 1977, on the basis ot average run-
off during the current year exceeds the "602(a)
Storage" requirement under any reasonable range
of assumptions which might be realistically applied
to those items which he is directed to consider in
establishing this storage requirement. Therefore,
the accumulation of "602(a) Storage" is not the
criterion governing the release of water during the
current year. The Lake Powell active storage fore-
cast for September 30, 1977, is scheduled to be
about equal 10 Lake Mead active storage forecast
for that date.

The plan of operation during the current year
based on average conditions is to release about
9,200,000 acre-feet of water from Lake Powell, in
accordance with section 602(a)(3) of Public Law
90-537.

Whirlpool Canyon belOW Echo Park, Flaming Gorge.