About the Refuge

Salton Sea stretches into the distance, viewed from a hilltop. In the foreground are shrubs and sandbars studded with birds. A geothermal powerplant can be seen in the near distance. Furthest out are the purple outlines of desert mountains against an orange-and-purple sunset sky.

The refuge is located within the Pacific Flyway, an important migration route for birds. The refuge's habitats and the Salton Sea are vital to these migrating birds as a resting place and wintering area. The refuge was established as a sanctuary and breeding ground for birds and other wildlife when 32,766 acres were set aside in 1930.

The Sonny Bono Salton Sea National Wildlife Refuge is located in California’s Imperial Valley, 40 miles north of the Mexican border at the southern end of the Salton Sea. The refuge has two separate managed units, 18 miles apart. Each unit contains wetland habitats, farm fields, and tree rows. The land of the Salton Sea Refuge is flat, except for Rock Hill, a small, inactive volcano, and is bordered by the Salton Sea on the north and farmlands on the east, south, and west.

Because of its southern latitude, elevation of 227 feet below sea level, and location in the Sonoran Desert, the refuge sees some of the hottest temperatures in the nation. Daily temperatures from May to October exceed 100°F with temperatures of 116°-120°F recorded yearly. The Salton Sea Authority has measured the current salinity of the sea to be 60 PPT. By comparison, the ocean water is approximately 35 PPT. Despite the harsh environmental conditions, the Salton Sea supports one of the most diverse avian compositions in the United States as well as a host of endangered and other wildlife species.

The Salton Sea is the most recent form of Lake Cahuilla, an ancient lake which has cyclically formed and dried over the centuries due to natural flooding from the Colorado River. The current Salton Sea was formed when Colorado River floodwater breached an irrigation canal being constructed in the Imperial Valley in 1905 and flowed into the Salton Sink. For decades, the Sea continued to receive sufficient quantities of water from irrigation runoff and the New and Alamo rivers, providing fresher water to the Salton Sea. This lake in the desert became a favorite getaway for Hollywood stars, and the Sea was stocked with sport fish to entice anglers. In 1930, 32,766 acres were set aside to establish the Salton Sea Refuge. At 37,900 acres today, the refuge is designated as an Important Bird Area by the American Bird Conservancy and a Regional Shorebird Reserve by the Western Hemisphere Shorebird Reserve Network.

Since its initial flooding, the Salton Sea has attracted a tremendous diversity of birdlife. Drawn by the marine-like waters, freshwater habitats, and marshes, birds of the Pacific Flyway have sought out this wetland oasis to re-fuel before continuing south. The Sea has been a winter home for more than 90 percent of the western population of American White Pelicans and has hosted millions of eared grebes during their southward migration. On the refuge and immediate surrounding area, over 400 species of birds have been documented.

But over time, the evaporation of water in the hot desert, combined with fallowing of farm fields to supply additional water to San Diego County and lack of outflow, has continued to decrease the size of the sea. This results in a highly saline body of water that is losing its ability to sustain fish and organisms essential for migrating birds that depend on it. In a different time, other water bodies would have provided alternate spots for migrating birds, but loss and degradation of suitable habitat in this part of the Pacific Flyway necessitates the Salton Sea remain a staple of the flyway.

In 1998, the refuge was renamed after Congressman Sonny Bono to Sonny Bono Salton Sea National Wildlife Refuge, who helped inform the U.S. Congress of the environmental issues facing the Salton Sea as well as acquiring funding for this Refuge to help it respond to avian disease outbreaks and other habitat challenges at the Salton Sea. Efforts to address the restoration of the Salton Sea have been in process for many years and will continue for many more.