In ‘Pulse Flow,’ Colorado River Reaches Its Delta For First Time This Century

May 23, 2014 by

By Ari Phillips


CREDIT: Shutterstock

It would seem a mirage. A sliver of water pulsing unevenly through the desert, just barely reaching the Gulf of California. A small fraction of the flow it started out as 1,500-miles earlier at the headwaters of the Colorado River in the Rocky Mountains. On May 15, a high tide reunited the Colorado River and its final destination for the first time in 16 years after water demand and allocation has kept it back for most of the last 50 years. And for the next five years, at least, it will happen annually.

This is not the result of increased water supplies or reduced demand. The West, especially California, is in the grip of a severe drought and climate change is predicted to make the entire region hotter and drier. At the same time the population continues to grow and irrigated agriculture is as embedded in the economy as ever. No, the meeting was the result of a 53-day flow from a planned pulse — an artificial flooding meant to at least somewhat restore the river’s parched, saline delta.

An international agreement between the U.S. and Mexico called Minute 319 allocates about one percent of the river’s flow to a five-year effort to recreate the formerly naturally-occurring spring floods in the delta. If it works out, some of the many fauna and flora that used to inhabit the delta will start to return. The delta once housed some two million acres of wetlands brimming with birds and wildlife.




“U.S. and Mexican policymakers, water agencies and conservation organizations are taking a major step to right the wrong that has been done to the Colorado river delta,” wrote Jennifer Pitt, Colorado River Project Director at Environmental Defense Fund. “Never before have we deliberately sent water below Morelos Dam — the last dam on the river just south of the U.S.-Mexico border — to benefit the environment.”

Though the amount of water is ultimately small — less than one percent of the river’s historic flow — it could be especially helpful for birds that are accustomed to nesting in the area.

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