WSP04344

• File Number: 8282.600.10
• Description: Colorado River Operating Annual Reports
• Basin: Colorado Mainstem
• Date: 1/1/1987
• Author: USDOI/BOR
• Title: Operation of the Colorado River Basin 1987 Projected Operations 1988
• Water Supply Pro - Doc Type: Publication

Actual Operations Under Criteria - Water year 1987

The initial plan of operation for water year ending September
30,1987, based on forecasted inlIow conditions for October
through January and average inlIow cooditions through the
rest of the water year 1987 called for scheduled releases from
Lake Powell of 14,7 million acre-feet (MAP), This plan of
operation would have created 5.5 MAP of vacant space in the
Colorado River reservoir systcm by the end of September
1987, of wlUch 2,0 MAFwould have been in Lake Powell, With
this plan of operation the contents of Lakes Powell and Mead
would have been within 1.6 MAP of each other at the end of
September 1987,

The April through July forecast of runoff into Lake Powell
made on January I, 1987, was 9,5 MAP or 116 percent of the
long term average, This long term average is calculated by the
Bureau of Reclamation using 80 yeats of nalma! flow data
(1906-1985) and current depletion levels. Accordingly,
releases from Glen Canyon powerplant were maintained at
28,000 cubic feet per second (cfs) for January, The monthly
April-July forecasts decreased each month until on May I, it
was at 7,0 MAP or 86 percent of average, In response to the
lower forecasts and to insure filling Lake Powell the releases
averaged about 65 and 40 percent of maximum power plant
capacity for the months of February, and March through May,
respectively,

Lake Powell inlIows remained about average through the
spring runoff with a snowmelt runoff peak of 52;800 cfs being
observed on May 21,1987. The aclual unregulated April-July
runoff into Lake Powell was 7,8 MAP in 1987, or 96 percent

of average, The lake reached its maximum elevation on June
25, of 3,698,47 feet, or 99 percent full. Unregulated runoff is
the inlIow to Lake Powell adjusled for the change in storage
of the upstream reservoirs discussed in this report.

The total unregulated runoff for water year 1987 at Lake
Powell was 13,6 MAP or 114 percent of the long-term averagc,
Water supply for the San Juan River above Navajo Dam for
the water year was at 185 percent, while the Gunnison River
above BlueMesaDam wasat103percent and the Green River
above Flaming Gorge Dam was at94 percent of the long-term
average, Total releases from Glen Canyon were 13.6 MAF
while the regulated inlIow for the year was 14.1 MAF,
Aggregate Colorado River storage at the end of the year was
55.0 MAF representing a decrease of 0,7 MAF from the
, I
prevlOUS year.

Commencing in 1986 the opcration of the Colorado River
Reservoir System was coordinated with Federal and State
interests in the Colorado River Management Task Force. The
task force is comprised of representatives from each of the
Seven Basin States, the Upper Colorado River Commission,
the International Boundary and Water Commission, Western
Area Power Administration, and the Bureau of Reclamation.
The Task Force and was implemented by Secretary of the
Interior Donald p, Hodel. It represents a comprehensive
effort by the Seven Colorado River Basin States and numerous
Federal agencies and serves as a technical forum for resolving
operational issues on the Colorado River.

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