The Salton Sea is 35 miles long and 15 miles wide, located in the lowest portion of the desert valley in Imperial and Riverside counties. Agricultural irrigation drainage of 1.36 million acre-feet per year is the primary source of maintaining the sea's elevation. The sea's average depth is 29.9 feet, with the deepest point measuring 51 feet. High levels of salinity in the sea continue to pose an environmental problem. Colorado River water carries about one ton per acre-foot of salinity, and is an ongoing concern. Algal bloom and the subsequent by-products of decomposition (botulism) have led to recent fish and bird die-offs. These problems have gained the attention of local, state and federal officials who are now looking into solutions to clean up the sea. Given these fish and bird die-offs, the sea still continues to provide a vital link in the Pacific Flyway by offering vast aquatic and wetland habitats in a region where water is scarce and where historic wetlands have been developed. 

Background
Imperial Valley's history reveals that the Salton Sink, which is largely below sea level, was once the bottom of a prehistoric sea and the Gulf of California originally extended north into what is now the Imperial and Coachella valleys. Evidence of marine life and shells high on the sides of the local mountains indicates that the entire region experienced a tremendous up-thrust resulting in the birth of the region's mountain ranges. Gradually, over time, vast quantities of silt deposited by the Colorado River formed a delta closing off the northern arm of the basin from the gulf. Periodically, the river overflowed its natural levees and filled the valley between the mountain ranges to form a vast lake, Lake Cahuilla (about 30 feet above sea level). Traces of Lake Cahuilla, named after the ancient tribe of Indians who inhabited the shoreline, can still be seen along the mountains to the west of the northerly end of the sea and in the sand dunes toward Glamis.When construction of the Imperial Canal was completed in 1901, the sink was dry and the canal diverted water for irrigation from the Colorado River just upstream from the Mexican border. After about four years, silt deposits led to attempts to relocate the diversion a short distance downstream from the Mexican border. However, unusual winter floods breached the diversion structure in 1905, and for the following 15 months, the entire flow of the Colorado River poured through Mexicali, Imperial Valley and into the Salton Sink, threatening destruction of farming and thousands of homestead families. After many months and high costs the river break was finally closed in the spring of 1907 and the reestablished lake was named Salton Sea.Click here for a map of the various canals which drain into the Sea. 

Elevation
The Salton Sea's average elevation in 2000 was 227 feet below sea level. This is only five feet higher than the lowest point in Death Valley. In 1907, the Colorado River stopped flowing into the sea, and evaporation greatly exceeded inflow, resulting in a rapidly declining water level until 1924. Today, evaporation remains the only outlet as the sea exists in a closed basin. Increased irrigation development, improved agricultural drainage systems and several major rainstorms caused inflow to exceed evaporation, which resulted in a gradual rise in the sea until 1980. Decades of increased elevations have caused damage to agricultural, recreational and residential properties along the sea's shore. After 1980, the elevation stabilized somewhat due largely in part to IID's water conservation programs. Today the surface covers about 250,000 acres and contains about 7.5 million acre-feet of water evaporating at a rate of 1.36 million acre-feet each year. 

Water Conservation
It was the rising level of the Salton Sea that focused public attention on water use practices at the Imperial Irrigation District. Although IID began water conservation programs initially in the mid-1950s, the effects of these water conservation programs were not readily recognized as stabilizing the level of the sea until 1980. Despite savings of more than 100,000 acre-feet annually with these early conservation programs, state, federal agencies and several court decisions prompted a more aggressive plan to conserve water and lower the elevation of the Sea. In 1989, IID and the Metropolitan Water District of Los Angeles signed a landmark conservation agreement that would conserve an additional 106,000 acre-feet of water each year. 

Pollution
New River pollution from Mexico, although an issue at the border, is not significant as the river enters the Salton Sea. In fact, by the time the river reaches the sea, the water quality has improved due to the addition of agricultural drain water and through natural cleansing occurring in the intervening 60 miles.The sea is considered a Rec I swimmable water body by the California Regional Water Quality Control Board. The primary water quality problem currently facing the sea is the salinity level. Agricultural pesticides have never been detected in the sea at levels to cause a public health concern. 

Selenium
Selenium, a sulfur-like element, is to blame for waterfowl deformities at the Kesterson Reservoir in Merced County, California, and has been detected in Salton Sea fish in concentrations exceeding state advisory levels. As a result, the public has been cautioned about consuming large quantities of fish from the sea (currently under reevaluation). Given this fact, abnormalities in Salton Sea wildlife have not yet been detected. Selenium found in the Imperial Valley is imported with Colorado River water used for irrigation and does not naturally occur in the Imperial Valley. State and federal agencies are now looking more closely at studies on the impacts of selenium at the sea. 

Salinity
The salinity concentration of the Salton Sea is 25 percent higher than ocean water and Salton Sea wildlife as well as the sport fishing industry is threatened by these rising salinity levels. All salts that drain from the surrounding agricultural lands of the lower Colorado River and Mexico are deposited there. The high evaporation rate of the desert climate removes water from the sea each year, but leaves salt behind that becomes more and more concentrated. The annual water inflow is currently 1.36 million acre-feet with an annual salt intake of 4.5 million tons. 

Stabilizing the sea
In 1986, at the direction of the governor of California and the California Resources Agency, the Imperial Irrigation District joined a group of 20 interested agencies and formed the Salton Sea Task Force. Their goal is to find workable solutions in stabilizing the elevation and salinity of the Salton Sea. The statewide group studied solar pond technology, pump-out facilities and diked impoundments, among other options, along with possible funding sources.In 1993, the Salton Sea Authority was formed under a Joint Powers Agreement between the counties of Imperial and Riverside, IID and the Coachella Valley Water District. The group was organized to work with the state of California, the federal government and the Republic of Mexico to develop programs that will ensure continued beneficial use of the Salton Sea. In addition, IID is working with the U.S. Fish & Wildlife Service to develop marshlands for water quality improvement and to provide habitat for endangered species along the Salton Sea.The Salton Sea has evolved over the years from human induced changes and natural processes. Local, state and federal officials will continue to play active roles in efforts dealing with the restoration and preservation of the sea. This intervention will be expensive, but is necessary to save the sea's economic, environmental and recreational values. 

Pacific Flyway
The Salton Sea is a critical component of the habitat base that currently sustains migratory birds of the Pacific Flyway. Wetland losses within the state of California exceed 90 percent of the acreage present at the time of statehood and is one of the reasons why the sea has become an important wintering and staging area for migratory birds. Populations of up to 1.5 million Eared Grebes have been documented at the sea during recent years along with up to one-half of California's wintering White-faced Ibis, tens of thousands of shorebirds, waterfowl and White Pelicans. Nearly 40 percent of the nesting Black Skimmers in California are found at the sea along with significant breeding colonies of Double-crested Cormorants and Caspian Terns and the largest breeding population of Gull-billed Terns in western North America. In total, more than 380 species of birds have been recorded at the Sonny Bono Salton Sea National Wildlife Refuge, the largest number of species found on any national wildlife refuge in the West. Endangered species are also prominent at the sea. A significant portion of the Yuma Clapper Rail population is dependent upon the sea and the drains that feed the sea. Desert Pupfish are another prominent species present as are endangered California Brown Pelicans. Facts About the Salton Sea

• Over 200,000 visitors each year visit the sea's recreation areas and wildlife refuge.
• The state park has 1,400 campsites, five campgrounds, hundreds of picnic sites, trails, playgrounds, boat ramps and a visitor center.
• Activities at the sea include boating, water skiing, fishing, jet skiing, hiking, bird watching and sail boarding.
• The lake is known as the fastest boat racing lake in the nation because its high salt content causes vessels to be more buoyant.
• Four million birds are estimated to use the sea daily in the winter, more than any other resource in the nation.
• The sea is also a vital link for waterfowl and shore birds on the Pacific Flyway.
• Nearly 400 species of birds have been observed at the sea - almost half of the 900 species known to exist on the North American continent.
• IID maintains 17 miles of dikes that protect adjacent farmlands and other property from flooding.
• Imperial County has seven geothermal power plants generating 380 megawatts of installed geothermal generating capacity around the Salton Sea and is currently the second largest producer of geothermal-generated electricity and mineral recovery in the U.S.
• The Salton Sea geothermal system is the hottest water-dominated system in the world.

For more information regarding: revitalization visit the Salton Sea Authority; or the Salton Basin and Colorado Delta you can visit the SDSU Center for Inland Waters website; or for travel and tourism information you can visit GORP.com.