New Report Offers Strategy to Save/Restore Lower Colorado River Delta

Once an amply watered region, its willow thickets, mesquites and cottonwoods providing shelter and habitat to many and varied species of bird and animal life, the Lower Colorado River Delta has become an environmentally troubled area.

A recent Sonoran Institute report calls for an environmental rescue mission to save the delta and restore and protect it as functioning ecosystem. Despite its present bleak environmental conditions, the 82-page report is hopeful that the delta can be brought back from the brink.

The delta is where the Colorado River once emptied into the sea, south of Yuma; it is literally at the end of the line. Very little flow reaches the delta after upriver diversions to farms and cities and storage behind reservoirs. Drought is further limiting water supplies. All of this has taken their toll; once 3,000 square miles, double the size of Rhode Island, the delta has shrunk 90 percent during the last 50 years.

To sustain remaining Colorado River Delta riparian habitat, the report says a minimum of 50,000 acre-feet of water is needed annually. A very small fraction of the total flow of the river — about three-tenths of a percent of the river’s historic annual flow — the amount is nonetheless another draw on a river already overdrawn.

The report says the Colorado River Delta now survives on accidental water that comes its way from leakages and inefficiencies in the Colorado River system and its canals. In these water-tight times efforts are being made to capture this water, further reducing flow to the Delta.

Shortages loom and environmentalists fear its consequences may be fatal to the delta. Proposing action to preserve the delta is now timely since plans are currently underway for dealing with possible, and increasingly likely Colorado River shortages. In a sense water allocation is back on the table, and environmentalists are concerned that such plans recognize the importance of restoring the delta.
“We have a unique near-term opportunity for bi-national cooperation as these water shortage rules are being developed,” said Luther Propst of the Sonoran Institute. “One of the goals of this report is to increase the flexibility of water allocation and delivery within the constraints of the current treaty between Mexico and the United States. All users of water from the river would benefit from additional flexibility.”

The report’s policy recommendations include: extending proposed water banking and trading mechanism to include Mexico and entities not currently Colorado River contractors; dedicating base and pulse flows to restore key riparian areas in the Colorado River Delta; encouraging water conservation by setting urban and agricultural targets, reducing subsidies on water-intensive crops and sharing best practices across the region; and creating mechanism to safeguard the well-being of rural U.S. and Mexican communities affected by ongoing transfers from agricultural to municipal water use.

The report also looks into the future to stimulate discussion and prompt action regarding Colorado River management. Four future scenarios are presented and are titled: a dry future; the market rules; Powell’s prophecy; and a delta and estuary once more. The scenarios are not intended as road maps but fictional narratives intending to stimulate discussion among stakeholders about the desired future of region.
Creating by the Sonoran Institute and Island Press and written by Mark Lellouch along with consultants Karen Hyun and Sylvia Tognetti, the report is available by contacting: The Sonoran Institute,
www.sonoran.org / 7650 E. Broadway, Suite 203, Tucson, AZ 85710, (520) 290-0828; or Island Press, www.islandpress.org / 1718 Connecticut Ave., N.W., Suite 300, Washington, D.C. 20009, (202) 232-7933. Copies of the report are available at either web site.

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