Colorado River Delta Identified As One Of Most Endangered Rivers Of 1998

The Environmental Defense Fund (EDF) today joined with American Rivers in calling the Colorado River delta in Mexico one of the most endangered rivers of 1998. The announcement was made at a press conference in Phoenix earlier today.

“EDF joins American Rivers in recognizing the delta as an endangered river,” said EDF scientist Dan Luecke. “Few people realize the tremendous beauty and conservation potential in the delta, but conservationists and scientists in both Mexico and the US are working there now. This is an unusual and important example of international cooperation in environmental restoration.”

EDF has been working for several years on a bi-national effort to restore remnant wetlands in the Colorado River delta. The delta, where the Colorado meets the Gulf of California in Mexico, was once a vast area of wetlands and salt flats covering over 3,800 square miles in the Sonoran Desert. However, the delta has been significantly altered by human activity, principally through the development and diversion of water for upstream use. Despite a century of degradation, significant wetland areas remain in the delta and provide critical habitat for shorebirds and migratory waterfowl, as well as habitat for several endangered species including the desert pupfish and the Yuma clapper rail.

EDF, together with scientists, resource managers and environmentalists from both the US and Mexico, are working to assess the condition of ecological resources in the delta and identify water management measures in the river basin that will help to restore critical wetland and riverine habitats. These results will be published in an upcoming EDF report.

Currently the delta receives water from agricultural drainage from the US and Mexico, and periodic flood flows. According to Luecke, “the long-term restoration of the delta will depend on securing a dedicated supply of water for the wetlands there, and better coordination of periodic flood flow releases from the US to Mexico. These are the types of changes needed to secure a healthy future for the delta.”

Recent water management changes proposed by the US. Bureau of Reclamation (BOR) could undermine these goals. These changes would alter the allocation of surplus water and allow off-stream banking of Colorado River water in the US, which could reduce the quantity of flood water available to the delta. A proposal by the BOR to operate the moth- balled Yuma Desalting Plant in Arizona would severely curtail agricultural drainage flows available to a major wetland area. Finally, it appears that a major US effort on the lower Colorado River to address endangered species issues will ignore the implication of those decisions for species or habitat in the delta, just downstream in Mexico. “Ultimately, we should be managing water in the Colorado River basin in a way that treats the river as a whole, rather than unrelated parts,” said EDF resource analyst Chelsea Congdon. ” Right now, the Colorado River delta is easily overlooked in water management decisions for the region. It lies across the invisible barrier that is the border between the US and Mexico. In fact, decisions made now about how water will be allocated or species will be protected could lock in management practices that make it much more difficult to accomplish environmental restoration in the delta in the future.”