The Sonny Bono Salton Sea National Wildlife Refuge (Refuge) is located in California’s Imperial Valley, 40 miles north of the Mexican border at the southern end of the Salton Sea. 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 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, located near Refuge Headquarters. The Refuge is bordered by the Salton Sea on the north and farmlands on the east, south, and west.
The courses of the New and Alamo Rivers run through the Refuge, providing fresher water to the Salton Sea. However, because the Sea has no outlet, the salt content of the water has increased steadily over time. Due to agricultural runoff and rise in the level of the Salton Sea, most of the original Refuge area has been covered completely by the salty lake. At present, only about 2,000 acres are farmed and managed for wetlands. Rye grass is grown on the Refuge as food for wintering geese in the area. However, as farming practices have changed, less water is being used on neighboring crops and therefore runoff into the Salton Sea has decreased over time, lowering the shoreline and further increasing salt content. In 1998, the Refuge was renamed after Congressman Sonny Bono, who played an active role in restoring the health of the Salton Sea to historical levels.