Restoring the Delta

Posted: 11-Mar-2003; Updated: 20-Jun-2003

The Colorado River Delta is at a critical juncture. Without any rights to water, the delta survives today on flows that reach it by chance. As competition for Colorado River water grows ever more fierce, these inadvertent flows are expected to disappear. The history of management on the Colorado reveals decades of neglect for fish and wildlife, but a happy accident of fate breathed life back into the delta at the end of the 20th century. Today we have an unprecedented opportunity to protect and restore this last naturally functioning reach of the lower Colorado River.

Beginning in the 1930's, the Colorado River was dammed and diverted on a grand scale to encourage development in the American Southwest. Numerous water projects on the Colorado fostered a massive agriculture business. As greater quantities of water were used, the river's flow dwindled downstream, and the delta, cut off from the water responsible for its existence, dried up and began to die.

In the early 1980's, the last big reservoir on the Colorado had finally filled, and the basin was hit with a series of wet years. During this time, even though annual consumption was as high as the river's annual average flow and even though the reservoir had a storage capacity of more than four times the river's annual average flow, still there was an excess of water. River managers had no choice but to send water downstream, and for the first time in decades the Colorado flowed all the way down to the Gulf of California. While no individual or organization planned for it, these floods in the delta restored highly productive marsh wetlands and native riverbank forests.

Before this revival, the Colorado River delta was largely written off as a lost cause. It was generally assumed that the amount of water needed to restore it to life was simply unattainable given upriver demands. But the area has demonstrated a remarkable resilience, and over the last two decades has been reborn. But given the antiquated system of water allocation that does not include water rights for the Colorado River delta itself, the delta is burdened by increasing demands for water that threaten to dry it up once again.

Here are our recommendations:

Develop a binational agreement for delta restoration. All Colorado River water storage is in the United States, and U.S managers control the river's flow. Almost the entire Colorado River delta is located in Mexico (the only part in the U.S. is a reach of 24 miles on the east side of the river below the last dam). Neither country can restore the delta on its own. Some preliminary agreements between the two have recognized the delta's importance to both, but they have yet to agree on a restoration vision and plan much less implemented one.
   
Dedicate water to the delta ecosystems. Water users in the U.S., specifically in the Upper Colorado Basin, are projected to increase water use in coming decades, and long-term hydrologic reports indicate that extended droughts are a fact of life in the Colorado River basin. The delta will not survive under today's management rules, which leave water for the environment to chance. The Colorado River delta and the plants and animals that live there need water, and the only way to guarantee this is to dedicate an instream flow.

Manage existing flows for the benefit of delta ecosystems. Because the water that reaches the delta is not legally allocated to sustain the environment, no agencies are managing the flows for maximum benefit to the plants and animals that live there. By deliberately managing water that flows in the main channel of the river, as well as the water that drains from nearby farms, the Bureau of Reclamation in the U.S. and the National Water Commission in Mexico could direct water to the places that need it the most, at the time it could do the most good.

Increase public participation. The agencies managing the Colorado River in both the U.S. and Mexico do not have a good record of including environmental and community stakeholders in the formulation of their plans, and consequently these plans frequently do not take environmental and community needs into account. Government agencies in the U.S. and Mexico, and especially the International Boundary and Water Commission, with a foot in each country, must all work closely with stakeholders.

Implement site-specific restoration. Conservation priorities in the Colorado River delta were defined in an experts' workshop in 2002 (read the report Mapping Conservation Prioities in the Colroado River Delta). Certain areas were targeted in the region, including riverbank forests, off-channel wetlands, and inter-tidal marshes. The workshop produced descriptions and water needs for each site, as well as information about threats and restoration opportunities. The Colorado River Delta offers many opportunities to restore habitat and restoration plans should not miss any of these.

View our slideshow Hope for the Colorado River Delta

LEARN MORE

The Colorado River Delta
Once a Mighty Delta: History
The Delta's Remarkably Resilient Flora and Fauna
A Decades-Long Tug-of War over Water
The People of the Delta: Yesterday and Today
Restoring the Delta

Another Step Forward for Restoring the Colorado River Delta (10/22/2002 article)

Mapping Conservation Strategies in the Colorado River Delta: A State-of-Knowledge Workshop (October 15-17, 2002)
A Delta Once More (1999 report from Environmental Defense)

University of Arizona web site