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How to Raise a River from the Dead

For the past half century, the Colorado River has rarely made its way to the Gulf of California. Without regular flow of the river’s nutrient rich water, the once teeming delta ecosystem and fishing communities have flatlined. Impeded by dams, major water diversions, and escalating droughts, this 100-mile stretch of the mighty Colorado River stopped flowing regularly to the gulf in 1960.



Eloise Kendy helped initiate the first pulse flow from Morelos Dam, March 23, 2014. | Eloise Kendy


But in an achievement of historic proportions, governments, scientists, and volunteers let loose a controlled flow of water on March 23 from the Morelos Dam near Los Algodones, Baja California and Andrade, California into the river’s delta. It took nearly two months for the water to travel approximately 94 miles to reach the gulf on May 15. Nature Conservancy hydrologist Eloise Kendy, an American Geological Institute-sponsored fellow in the U.S. Senate from 2003-04, is a key member of the team that implemented the experimental pulse flow. 

A pulse flow is a surge of water that periodically flows through a river – normally as the result of natural events such as spring storms or melting snow. This initial pulse flow is the first step in a five-year plan to restore a continuous base flow through the delta. While the volume of pulse flow water is minute compared with the 4.9 trillion gallons of water that flowed in pre-dam days, it will have clear effects on the ecosystem, and on the spirit of the people in delta communities. Due to the complex nature of the Colorado River system, scientists were uncertain if the water would reach the sea or if it would seep into the ground before that.

In the 1980s, the governments of the U.S. and Mexico, nonprofit organizations, and volunteers started an effort to bring water back to the delta to revive the habitat, economy, and inhabitants’ way of life. Signed in November 2012, the ground-breaking agreement between Mexico and the U.S. called Minute 319 outlines how the two countries will share and store water and remains in effect for five years.

“My fellowship experience helped me appreciate the federal bureaucracy and politics that made Minute 319 possible. Of all the 260 rivers that cross or form international borders, this is the world’s first water allocation for the environment,” said Kendy.

“Standing on the riverbank surrounded by joyful revelers, I finally realized deep in my heart that rivers are for people and nature – and neither should ever have their river taken away. That alone will drive me to see this experiment to its completion, tally the lessons it teaches us, and apply them to future pulse flows until we get it right."

Eloise Kendy

The restoration of river flow will also benefit people. “What’s one incredible outcome that had nothing to do with ecological recovery?," asked Kendy. "San Luis Rio Colorado got its namesake river back. For decades, the broad channel under San Luis Bridge had been used only for drag races. The city’s younger residents had never seen the river flow. Now, if only for a few weeks, San Luis had its river once again.”

A coalition of U.S. and Mexican conservation groups, Raise the River, is raising money to purchase and lease the additional water rights required to ensure base flow in the future.


"The Pulse Flow Reaches San Luis Rio Colorado" | Sonoran Institute


Learn more:

Colorado River: Pulse Flow Q&A with Eloise Kendy. Nature Conservancy. Accessed May 5, 2014.

Fountain, H. (2014, April 16). Relief for a Parched Delta. New York Times. Accessed May 5, 2014.

International Boundary and Water Commission. “Colorado River Reconnects with the Sea Following Historic Release Of Water for the Environment.” May 16, 2014.