Glen Canyon Dam
Water management in the West



On this page are links to three Web Pages, which together make up the package:


(For a letter from the Clinton Administration stating their official position on draining Lake Powell - click here)

The information package contains:

1) A question and answer format concerning the feasibility of draining Lake Powell and the value and benefits of Lake Powell.

2) A response to David Brower’s accusations concerning the safety of the Glen Canyon Dam and other misleading information that he provided in an interview with the Lake Powell Chronicle in January 1997.

3) What the impacts of draining or drawing down Lake Powell would be.


We, the Friends of Lake Powell would like to provide some additional information for your consideration. The majority of the data and information was obtained from the Bureau of Reclamation's Upper and Lower Colorado Regional offices. Additional information and data was taken from the Lake Powell Research Project. Researchers from Dartmouth College, the University of California, Los Angeles, and the University of New Mexico, among others conducted this project.

In the first section of the package the question "Can Lake Mead handle the storage which would be necessary if Lake Powell were drained?"

The Bureau’s response is "The long term answer is no…..even for the scenario of present Upper Basin storage." As stated at the beginning of the section "[The Bureau of Reclamation] does not intend to spend funds to conduct such a study unless directed by Congress or the Secretary [of Interior]. In the absence of authority… would be inappropriate to spend money on such a study."

In support of the response to the question of Lake Mead’s capability to handle the storage requirements, significant, recent, historical data points to the very real potential for water shortages if Lake Powell was drained. A drought (1988-1993) in the watershed supplying the Colorado River resulted in a use of the combined water storage of Lake Mead and Lake Powell of 13.5 million acre-ft. If Lake Powell had not existed during this period Lake Mead would have been drained to half capacity, and Hoover Dam electrical generation would have been in jeopardy in December 1992. These effects are difficult to argue with, they are based on the water use at the time and the existing water supplies.

If a more severe drought were to occur without Lake Powell in place, the next thing to happen after the loss of Hoover Dam electrical generation, would the be curtailment of the water supplies to the Central Arizona Project (CAP) and Southern Nevada. The supply to Southern Nevada would be totally unavailable when Lake Mead Capacity falls below the 1,050 ft. elevation. The next lower basin water users to be curtailed (from present usage levels) would be the Metropolitan Water District including Los Angeles and San Diego County.

Reviewing historical data from the last century, droughts much worse than that experienced in the last decade occurred several times.

This historical data is contained in the Lake Powell Research Project Bulletins (Availability can be determined by contacting the Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90024). Our copies of the data were found in the John Wesley Powell Museum in Page, Arizona. The data is based on tree ring samples taken in the watersheds for the Colorado River. The data was correlated with measured flows from 1906 through 1961. The figure below was developed using this data and information from the Bureau of Reclamation. The assumptions involved, and the data sources are on a separate page, which can be linked to at the bottom of the page.

Looking back to the last century, it can be seen in the figure below, that Lake Mead would have been completely drained several times. It also shows that for significant periods of time there would have been massive flows over the spillways, which would cause damaging flooding downstream.

This type of river flow may be more natural but the consequences, to the parties dependent on water management to provide adequate water supplies during droughts and flood protection during years of heavy precipitation, would be disastrous.

These estimates are not the result of an official Bureau of Reclamation study, since they do not plan to do a detailed study until directed to do so. The estimates are conservative and reasonable. The Upper Basin usage was held at current levels (4.2 million acre-ft for consumption and evaporation), and the Lower Basin usage was held at the entitlements (7.5 million for the States and 1.5 million for Mexico). The water usage in both basins has grown and will continue to grow.

The 1800’s water scenario would result in the following (using full years - there would be many more partial year losses):

California’s entitlement is 4.4 million acre-ft. Use in 1994 and 1995 averaged 5.1 million. (During 1996 water releases from Glen Canyon Dam were well above average due to the "artificial" Grand Canyon flood and above normal precipitation in the watershed. The California use in 1996 was 5.3 million.)

The Metropolitan Water District (MWD) aqueduct has an capacity of over 1.1 million acre-ft/year, but only half of that capacity, is part of California’s Colorado River entitlement. The other half requires a surplus to be declared by the Secretary of the Interior. MWD use of water increases dramatically in time of drought. The city of Los Angeles alone (one of 27 members of MWD) used 1/10 of the total California entitlement during the drought of 1988-1993. Over 90% of the City of San Diego’s water supply during droughts is obtained from the MWD.

If Lake Powell is considered in the hypothetical scenario (that history suggests could very conceivably happen again) neither reservoir would be completely drained, and the Bureau of Reclamation could optimize storage such that water deliveries and electrical generation could be optimized. Without Lake Powell in place a severe drought condition could result in water use curtailments in the metropolitan areas of Southern California, Southern Nevada, Arizona, and Utah. There would also be the loss of agricultural water to all seven states taking water from the Colorado River drainage basins.

In the second section of the Bureau package there is nothing to add. The dam is safe, and the problems with the spillways, which occurred in 1983, have been corrected.

In the third section we do have a comment concerning the "Summary Table of Impacts". Under "Endangered species mitigation potential" the "Completely Drained Concept" has a "Restored" status. We would argue that the verbiage in the information package and the Bureau’s EIS makes it clear that this is very questionable. It is very improbable that the Grand Canyon could be returned to the pre-dam conditions regarding the endangered fish populations. The only way this could happen would be to remove all the dams on the Colorado River system, as well as the non-native, introduced aquatic species.

A concluding point:

One has to wonder if the Sierra Club’s Board and the Glen Canyon Institute are promoting the draining of Lake Powell to regain Glen Canyon or to force the reduction/elimination of agriculture in, and the depopulation of the American Southwest including Southern California.


Information from the Bureau of Reclamation regarding proposals to drain Lake Powell:

Data on possible impacts & technical information
Response by the Bureau of Reclamation to David Brower’s
points published by the Lake Powell Chronicle in January 1997
Impacts of drawing down Lake Powell to allow exposure of Glen Canyon

Questions or comments regarding the data
on this page may be directed to: