Volume 5, Number 17 - July 21, 2005
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Upper Basin precip on rise
Hydrologic conditions have improved over the past 10 months in the Upper Colorado River Basin, according to John Shields, interstate streams engineer with the Wyoming State Engineer's Office. This is after five consecutive years of drought.
Precipitation in the Upper Basin has been above average since last fall, and fall rains increased river flows and helped to reduce soil moisture deficits caused by the drought.
Shields pointed out that November 2004 was the first month with above-average inflow to Lake Powell since September 1999.
Shields, in a report to the Green River Basin Advisory Group, noted that Lake Powell reached a low elevation on April 8, at 3,555 feet (145 feet from full pool). Reservoir storage had declined to 33 percent of live capacity. The last time Lake Powell had been this low was in May 1969, when the lake was filling. The water surface elevation has been increasing, to its current storage of 12.5 million acre-feet, which is 52 percent of live capacity.
Inflow in water year 2002 was the lowest ever observed since the completion of Glen Canyon Dam in 1963.
"Lake Powell is doing exactly what it was designed to do," Shields said. "The severity of the drought has, however, drawn the attention of everyone, including federal water managers."
The Bureau of Reclamation has opened a public process for the development of new, low-water management strategies for Lake Powell and Lake Mead. Among the management strategies anticipated are shortage guidelines for the Lower Colorado River Basin.
Shields reported, "The strategies will likely identify those circumstances under which the Department of the Interior would reduce annual Colorado River water deliveries and the manner in which annual operations of the Colorado River reservoirs would be modified under low reservoir conditions. The Department expects the strategies to provide guidance to the Secretary's Annual Operating Plan decisions, and provide more predictability to water users throughout the Basin, particularly the Lower Basin states of Arizona, California, and Nevada."
The annual operating plan specifies whether the amount of Colorado River water available to be released from Lake Mead to Lower Basin users in a given year will be "normal" (7.5 million acre-feet), "surplus" (more than 7.5 million acre-feet) or "shortage" (less than 7.5 million acre-feet).
Shields reported that adoption of detailed guidelines for making shortage determinations would enable water users in the three states to identify reservoir conditions under which less than 7.5 million acre feet would be available for use on an annual basis, as well as the amount of any potential future annual reductions in water deliveries.
"This would allow these users to better plan for periods of less than full water deliveries," Shields said. "Additional operational tools may also facilitate conservation of reservoir storage, minimizing the adverse effects of long-term drought or low-reservoir conditions in the Colorado River Basin."
Shields pointed out that the reason the feds are proceeding is because the states have been unable to come to agreement on what the shortage criteria should look like - and in fact, have been unable to agree on whether the release out of Lake Powell this year should be 8.23 million acre-feet or a lesser quantity.
Although the Upper Basin States had asked the Secretary of the Interior to reduce the amount of the total volume of release from Lake Powell this year below 8.23 million acre-feet in order to protect conservation storage in the reservoir, Secretary Gale Norton declined, instead deciding to maintain Colorado River water releases from Lake Powell at the AOP-established level of 8.23 maf.
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