Bureau of Reclamation moving less water through Colorado River dams
The Bureau of Reclamation is moving less water through Hoover and Davis dams than one year ago, largely because of more moderate weather.
As of June 17, the average release was 18,100 cubic feet per second (cfs) for Hoover Dam and 14,400 feet at Davis Dam.
Those numbers one year ago were 20,400 cfs for Hoover Dam and 17,600 cfs at Davis Dam.
A cubic foot per second is equivalent to about 7.5 gallons per second.
"Last year the difference was we were delivering surplus water to Southern California, so we had a little extra water flowing through the system," said Robert Walsh, public affairs officer with the Lower Colorado Region of the Bureau of Reclamation.
"But other factors go into the determinations.
"Last year was hot and dry, so we moved a lot of water to the irrigation districts.
This year has been a little cooler and not as windy, so the demand is not as high."
Water levels at lakes Mead and Mohave continue to drop from one year ago.
Part of that can be attributed to the Colorado River Basin being in its fourth year of drought, Walsh said.
Lake Mead's elevation was 1,144.68 feet at the end of May, down from 1,162.39 feet one year earlier.
Lake Mohave also dropped, although not as much, from 644.4 feet at the end of May 2002 to 643.6 feet at the end of last month.
The bureau controls water levels in Lake Mohave.
But the level of Lake Mead is largely dependent upon upstream snow pack and runoff, Walsh said.
The maximum elevation of Lake Mohave is 645 feet, a level not reached in a long time, Walsh said.
The maximum level at Lake Mead is 1,221 feet.
The lake was last at that level in July and August 1983.
"We try to hold Lake Mohave around 644.5 feet," Walsh said.
"That provides a little extra space in case of unexpected runoff or if we want to release water from Hoover Dam for any reason.
"But after July we'll take Mohave down to 631-632 feet.
The potential for side inflows from summer thunderstorms is high, so that gives us some extra storage space."
Lake Mead is expected to fall to about 1,139 feet by the end of the year as more water is taken out of the lake than flows into it, Walsh said.
Snow runoff is down about 50 percent upstream at Lake Powell.
That has significantly affected people in the Upper Colorado River Basin north of Lee's Ferry and to a lesser extent the Lower Colorado River Basin.
"Recreation enthusiasts in the lower part of the basin probably won't notice any difference in water levels," Walsh said.
"Come to Lake Mead and it's not as full as three years ago, but there's still lots of water and good beaches.
"The same is true for agricultural and municipal water users.
They're getting their full entitlement this year."
The design of the Colorado River system means the water situation is not as bad as it could be after four years of drought, Walsh said.
However, levels have dropped 90 feet at Lake Powell and 70 feet at Lake Mead during the last three years, he added.
"We still need people to be judicious in their use of water," Walsh said.
"If the drought continues, we need to ensure we don't use water in ways or amounts we don't need to use it."