California Ex Rel. Imperial County Air Pollution Control District v. U.S. Department of the Interior

The Saltón Sea — the largest inland body of water in California — is a creature of accident. In 1905, water from the Colorado River breached an irrigation canal and flooded the then-dry Saltón Basin. After the initial flood, irrigation runoff from the Imperial and Coachella Valleys — supplied by the Colorado River — sustained the Sea for more than a century. The Sea has become a unique attraction for water-based recreation in the harsh southern California desert.

The Sea’s continued access to Colorado River water is in jeopardy. Over the last few decades Arizona and Nevada began to claim their full entitlements to the stream. California, which has long used more than its share, has been required to conserve. The affected California water districts ultimately agreed to transfer some Colorado River water from the Imperial Valley to urban areas in southern California. The Secretary of the Interi- or — who controls the delivery of River water — prepared an environmental impact statement (“EIS”), which, among other things, analyzed the effect of these agreements on the Saltón Sea. Despite noting some potentially serious environmental consequences, the Secretary eventually…