BOARD00281

• Board Meeting Date: 9/21/1998
• Description: Colorado River Basin Issues - Upper Colorado River Commissioner's Report - Increasing Colorado's Stored Water
• Board Meetings - Doc Type: Memo

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ITEAU OF RECL.fl.!I\!\.

Bureau of Reclamation
Boulder City, Nevada
August 28, 1998

Contact: Bob Walsh [phone]
Bruce Williams [phone]

FOR IMMEDlA TE RELEASE

Space-Building Releases Scheduled For Lower Colorado River;
Flows Will Be At Non-Damaging Levels, Help Reduce Potential Of Higher Flows In 1999

On September 9, the Bureau of Reclamation will begin making non-rl~m~ging, space,.building
flood control releases from Hoover, Davis and Parker Dams along the lower Colorado River.

Above average runoff this spring has left Colorado River storage reservoirs near capacity,
resulting in a high probability that non-damaging flood control releases of about 19,000 cubic
feet per second (cfs) from Hoover Dam will be iequired beginning in January 1999. Similar
releases were required in January, February and March oftbis year.

Under normal circumstances, Reclamation would not make space-buil~g flood control releases
from lower Colorado River dams until later in'the year. However, Reclamation believes it is
appropriate to begin space-building releases at this time as a precautionary measure to help
reduce the potential for higher flood control releases in 1999. Flood control releases:above
19,000 cfs could cause property damage along the river below Parker Dam and in the Yuma area,
where sediment buildup from a 1993 flood on,the Gila River has significantly restricted the
carrying capacity of the river channel.

Maintenance requirements at Parker and Davis dams this fall also contributed to the decision to
begin the space-building releases earlier than normal. The powerplants at each dam are required
to have one generating unit out of service for maintenance from October through December,
1998. TIlls work, which must be completed before the 1999 spring runoff, limits the amount of
water that can be released through the powerplants during these unit outages. '

The space-building releases will r~sult in average daily flows of approximately 15,200 cfs from
Hoover Dam; 15,100 cfs from Davis Dam; and 13,000 cfs from Parker Dam. These:releases,
which are typical during the summer months, are not expected to significantly increase the flow
in the river at Yuma, because most' of the excess flow will be carried in the' All-Amcican Canal
and discharged back to the river through Pilot Knob power plant. Depending on Mexico's use of
the water, flows below Morelos Dam could reach approximately 4,000 cfs. '

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