Report calls for decommissioning Glen Canyon Dam as the primary action needed to reduce current and future economic and ecological impacts of dam operations to the Southwest.
John Weisheit - (435) 259-1063/Mobile: (435) 260-2590
David Haskell - (928) 567-9873
As the Bureau of Reclamation begins developing plans for re-operating the nation's two largest dam and reservoir complexes with public meetings at Las Vegas and Salt Lake City this week, a new report released by Living Rivers reveals that Southwestern water users and the ecological health of the Colorado River would both be better served if one dam were removed.
"Hoover and Glen Canyon Dams may have been icons of 20th century civil engineering, but continuing to operate them in their present fashion is wasting water that could support more than six million people. In addition, Glen Canyon Dam is devastating the ecological integrity of the Grand Canyon and is creating a dam safety problem due to advancing sedimentation in Lake Powell," says John Weisheit, Living Rivers conservation director.
The analysis reveals that increased water use and decreasing supplies raise questions about the need for both dams, especially in light of their tremendous evaporation losses. The report concludes that it would be more efficient to eliminate Glen Canyon Dam from the system and utilize Hoover Dam and adjacent underground storage to capture the limited amounts of surplus water that may be available in the future.
Key findings of the 24-page The One-Dam Solution include:
More efficient water storage strategies are needed.
When Glen Canyon Dam was built, nearly 2.6 million acre feet (MAF) of surplus water flowed into Lake Powell annually, allowing the reservoir to fill in 17 years. However, increasing demand upstream has nearly eliminated these reserves. Demand has risen 100 percent since the dam was built and is projected to increase another 23 percent by 2020--placing demand well above the rivers' 13.5 MAF average annual flow.
Since 1979 there have been warnings that the Colorado River would fail on the supply-side because 11 percent more water has been allocated than the river can historically provide. Even more problematic is that Department of Energy research forecasts that climate change will cause Colorado River flows to decline 18 percent by 2040.
Precious water is being lost from the system
On average, Lake Powell and Lake Mead lose 1.3 MAF of water annually to evaporation, nearly ten percent of the river's annual flow.
It was not until the Autumn of 2004 that Lake Powell's storage actually factored into the water usage of people downstream. Prior to this time it caused the loss of 36 MAF due evaporation and to seepage into the surrounding sandstone. Underground Storage should be more widely utilized
Depleted groundwater aquifers along the Colorado River represent a storage solution that could eliminate much of the water now being lost. In California and Arizona alone it is estimated that suitable sites containing a total of 41 MAF of storage are available along the system, and potentially another 46 MAF nearby. Aquifer recharge infrastructure in place now have the capacity to recharge 1.4 MAF of Colorado River water annually.
There is one dam too many in the Southwest desert.
Removing Glen Canyon Dam from the system, using Hoover Dam to capture annual flows while expanding groundwater storage could recover 810,000 acre feet annually now being lost to evaporation. This is enough water to support 1.6 million households of four people each.
The Destruction of Grand Canyon Resources must be stopped.
More than $200 million has been spent in failed efforts to halt the demise of Grand Canyon National Parks's river ecosystem due to the impacts of Glen Canyon Dam. Four native fish are now extinct, one is in jeopardy and another is of special concern. Glen Canyon Dam has trapped the sediment necessary to maintain habitat and beaches for wildlife and recreation, as well as the stabilization of archeological sites.
Accumulating Sediment Presents a Serious Looming Problem.
Sediment is a major unresolved problem threatening the long-term operations of both Hoover and Glen Canyon Dams. Ultimately, sediment will have to be removed from one or both of these reservoirs. Removing sediment from Lake Mead rather than Lake Powell is the most feasible and least expensive likely alternative. While original estimates projected that sediment would not effect the safe operations of Glen Canyon Dam for another 60 years, scientists now warn that major problems could occur sooner.
Hydropower and Recreation are Incidental Benefits
Lower reservoir levels have already resulted in reducing Glen Canyon's power production by 40 percent. This loss has been seamlessly absorbed elsewhere in the energy market. The same is true of recreation, which at Lake Powell has dropped 50 percent in the past 15 years. Such uses were deemed "incidental" to water management when these dam were authorized, and should be treated similarly as new management strategies are developed.
"There will be no efficient solution to managing the growing crisis in Colorado River water management without seriously rethinking how these dams are used, or not," adds Weisheit. "And when doing so, it's clear than when it comes to saving precious water, and restoring Grand Canyon in the process, one dam is better than two."
Click here to download a pdf of The One-Dam Solution: Preliminary report to the Bureau of Reclamation on proposed reoperation strategies for Glen Canyon and Hoover Dam under low water conditions