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Glen Canyon Institute

Dedicated to the restoration of Glen Canyon and a free flowing Colorado River.

Fill Mead First


In 1922, the Colorado River Compact was signed by the federal government and the seven states in the Colorado Basin. The Compact allocated water rights between the states of the upper (New Mexico, Utah, Wyoming, and Colorado) and lower (Arizona, California, and Nevada) Colorado River Basin. This paved the way for Hoover and Glen Canyon dams, which impound Lake Mead and Lake Powell, as well as the entire Colorado River water management system.

Today, the Colorado River Basin is facing a water supply crisis. We now know that the Colorado River Compact was based on flawed projections that seriously overestimated actual future river flow and seriously underestimated future water demand. As a result, growing demand, relentless drought, and climate change are creating a water deficit of almost 1 million acre-feet a year in the Colorado River system. Both Lake Powell and Lake Mead reservoirs are half empty, and scientists predict that they will probably never fill again. The water supply of more than 22 million people in the three Lower Basin states is in jeopardy.

The region is also facing an environmental crisis. The ecological health of the Southwest is tied to the fate of the Colorado River. A century ago, the Colorado was one of the world’s wildest rivers. Its extraordinary variations in water flow, temperature, and sedimentation created a unique ecosystem that was once home to 16 endemic fish species — the largest percentage of any river system in North America.

The construction of more than a dozen dams during the last century has critically damaged the integrity of the Colorado River. Hundreds of miles of canyon and countless archaeological sites have been flooded, and dozens of wildlife species have been endangered. Glen Canyon Dam is one of the largest contributors to these problems, with major impacts that stretch from above Glen Canyon, through the Grand Canyon, all the way to the Colorado Delta in Mexico. In 1992, Congress passed the Grand Canyon Protection Act, which sought to modify Glen Canyon Dam operations to “protect, mitigate adverse impacts to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established.” Unfortunately, efforts to implement the act have been only partially successful.


GCI believes the time has come to change Colorado River management to address today’s new realities. This is the goal of our Fill Lake Mead First Project. Since Glen Canyon Dam was completed in 1963, the goal of water managers has been to keep both Lake Powell and Lake Mead full. Now, with two half-empty reservoirs, this policy no longer makes sense. Through our Fill Lake Mead Project, GCI is advocating a new approach that consolidates most of the water from both reservoirs in Lake Mead, with Lake Powell used as a backup in flood years.

The Fill Lake Mead First strategy would benefit the people and ecosystems of the Colorado River Basin and beyond. This approach would help to maintain a reliable water supply for millions of people who depend on Lake Mead, in major cities such as Las Vegas, Phoenix, Los Angeles, and San Diego, as well as on farms across the region. It would also help to restore Colorado River ecosystems. Water would be permitted to flow more naturally through Glen Canyon Dam, helping to heal the damage done by the dam to the Grand Canyon. A lowered Lake Powell would expose many more portions of Glen Canyon that have been flooded under the reservoir, allowing them to recover their natural beauty and integrity. This would all be done without infringing on the water rights and needs of the Upper Basin states.

GCI recently completed a study that analyzed water usage under the Fill Mead First proposal. Our study, which is currently undergoing the peer review process, shows that 500,000 acre feet of water could be saved each year in the Colorado Basin if the Fill Mead First proposal were implemented. That’s enough water to serve the annual needs of half of Los Angeles.


The Fill Lake Mead First Project is an expansion on an idea that has been proposed before — including by David Brower, who helped to found Glen Canyon Institute. In the past, this strategy was considered “politically unrealistic.” Now, in the face of unprecedented water supply and environmental challenges, the various people and institutions involved in Colorado River water policy are increasingly open to new ideas that they never would have considered before. GCI is optimistic that this will lead to unprecedented, positive change in the next few years, for the benefit of the people and ecosystems of the Colorado River Basin.

The Fill Lake Mead First Project is still in its early stages and most of the work is behind the scenes. However, in the future, there will be important opportunities for the public to speak out. We will let our members know when these opportunities arise. Meanwhile, we will keep you up to date on our efforts to put this bold new plan into action.