Plea for Colorado Delta as water authority welcomes water banking
As south western states move ahead with 'water banking' plans for the Colorado River, environmentalists are seeking legal commitments for minimum flows for the river's lower reaches.
A coalition of US and Mexican conservation groups has sent a letter to their governments calling for an amendment to the 1944 water utilisation treaty between the US and Mexico which would allocate water for threatened ecosystems.
The groups contend that the lower Colorado River ecosystem is under stress as the bulk of the river water is stored and diverted to agribusinesses and cities, leaving little water for wildlife. In accordance with the 1944 treaty, the relatively small amount of water which reaches the lower reaches of the Colorado River at the US/Mexico border is diverted in its entirety by Mexico for its agribusinesses.
The groups believe the spilled water that serves to support this ecosystem is currently treated as wasted water by US state water and power agencies. These agencies have devised plans to use this ‘wasted’ water for activities such as off-stream storage, designation of surplus criteria, water transfers, and operation of the Yuma Desalting Plant.
The US Department of the Interior recently approved ‘water banking’ legislation for Nevada and Arizona which will allow the voluntary movement of Colorado River water among the lower basin states of Arizona, California and Nevada.
Welcoming the water banking legislation, SNWA Chair Mary Kincaid said: “It’s a great day for Southern Nevada. It gives us the opportunity to extend our water resources by more than 30 years. While this certainly does not eliminate the need for efficient water use, it does give us a chance to explore other water resource options,” Kincaid said.
For the past few years there has been surplus water available from the Colorado River, but currently Nevada has no way of accumulating any of that water for future use. “Historically, Colorado River water has been based on a ‘use it or lose it’ scenario,” Kincaid said. “Now we have a way to capture and retrieve that water when we need it.”
Once the rules are finalised, Nevada hopes to negotiate an agreement that will allow it to store as much as 1.48Bnm3 of water in Arizona. “The ability to store water in neighbouring Arizona is an important component of the authority’s long-term resource plan,” Kincaid said.
Secretary of the Interior Bruce Babbitt’s release of regulations governing interstate water banking is the latest phase in a process that began in 1994 when Arizona, Nevada, California, the Bureau of Reclamation and American Indian tribes began to discuss long-term regional water needs.
Arizona took a lead role when it passed a law in 1996 that created the Arizona Water Banking Authority. This law allowed the new authority to not only bank Arizona’s Colorado River water in its groundwater basin but also allowed banking for Nevada and California.
Under the proposed groundwater banking procedures, Nevada would receive credits for Colorado River water stored in Arizona’s groundwater basin. When the water is needed, Arizona would withdraw the stored water for its own use, then allow Nevada to utilise a similar amount of its Colorado River allocation. This process would eliminate the need for a prohibitively expensive interstate distribution system.
Environmentalists point out that, since the early 1960s, the Colorado River has reached the Gulf of California only when flows have exceeded storage capacity at Hoover Dam and are deliberately spilled by the Bureau of Reclamation. Forests, shrimp, and shore bird populations, among others, exhibit dramatic and healthy changes when this water is spilled into the ecosystem.
“The restoration of water flows to the Salton Sea, the Colorado River Delta, and the wetlands in the region will actively restore all of these natural sites and we are hopeful that Mexico will have both the biological and technical information support to formally request that the United States government keep the allocation permanent,” said Carlos Yruretagoyena, a board member of the International Sonoran Desert Alliance (ISDA).
The delta forests and marshlands and the marine habitats of the upper Gulf support nearby fishing and farming communities, as well as important populations of endangered species. The area is also a major migration corridor for songbirds and an important stopover for waterfowl along the Pacific flyway.
“State water and power interests dominating the Lower Colorado River Multi-Species Conservation Plan have also rejected allocating water for conservation of the delta, thereby undermining lofty promises of the plan and ensuring desiccation of the delta under the pretext of ecosystem management within the US,” said Bill Snape, Defenders of Wildlife Legal Director. “National boundaries should not be an excuse to ignore legitimate instream flow rights of the entire lower Colorado basin. Bi-national co-operators possess an historic opportunity to restore the region’s bloodline.”
The groups have called on the governments of Mexico and the United States to put together a new amendment to the 1944 treaty specifically allocating water for cross border, in-stream, and perennial Colorado River flows for conservation of the delta and Cienega de Santa Clara. A Letter of Intent signed in 1997 by Mexican Secretary Julia Carabias and US Interior Secretary Bruce Babbitt could become the basis for an ecological amendment or minute to the treaty of 1944, according to the coalition.
Legal precedent for conservation of the delta already exists. Mexico and the United States have a significant history of co-operation in the conservation of shared natural resources, including water, vegetation, and wildlife. Past co-operative efforts include at least 15 different resource conservation agreements between the two nations. Both the United States and Mexico have also passed their own laws for wildlife conservation. The US Endangered Species Act mandates species protection by US agencies irrespective of international boundaries.
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