Salton Sea Study Status Report

The Salton Sea is located in a closed basin in Riverside and Imperial Counties in southern California, south of Indio and north of El Centro. The Sea is situated in a closed basin, more than 200 feet below sea level and has no natural outlet. Although lakes have existed in this basin in the past, the current body of water formed in 1905 when a levee break along the Colorado River caused flows from the Colorado River to enter the basin for about 18 months. Since 1905, the Sea has fluctuated in size with varying inflow, and it recently has had a surface area of 365 square miles.

A balance between inflowing water and evaporation sustains the Sea. With no outlet, any salts that are dissolved in the inflow are trapped, although some do precipitate. Salt concentrations are currently about 44,000 milligrams per liter (mg/L), or about 25 percent higher than ocean water. Salinity will continue to rise under current conditions. It is highly likely that in the future, the inflow to the Sea will be less than it has been in the past. A reduction in inflow would cause the Sea to shrink and cause salinity to rise faster than it would have without a reduction in inflow.

A gradual increase in salinity and its consequences was recognized soon after the Sea was formed. Formulation of salinity control measures was reported as early as the mid-1950s. Since then, many alternatives have been proposed and analyzed. The alternatives presented in this report were developed to address the goals contained in the Salton Sea Reclamation Act of 1998. The Act directs the Secretary of the Interior to study options for managing the salinity and elevation of the Sea in order to preserve fish and wildlife health and enhance opportunities for recreation use and economic development while continuing the Sea’s use as a reservoir for irrigation drainage. The Act required that certain options be analyzed and required consideration of reduced inflows down to 800,000 acre-feet or less per year. Consideration of any option that included importation of water from the Colorado River was prohibited. Reporting requirements of the Act were met on January 27, 2000, when Secretary Babbit forwarded a draft EIS/EIR and several other reports to Congress. Since then, analyses have continued on options presented in those reports and on new options. The development and transmission of this report is not required by law.

This report provides a summary of the current status of the evaluation of alternatives currently under consideration. The primary purpose of the planning study was to evaluate possible methods of controlling the salinity and elevation of the Sea. The study also includes elements that address other issues at the Sea, such as high levels of nutrients. Fourteen alternatives providing a range of salinity and elevation control benefits and costs are presented in this report. For ease of presentation and understanding, alternatives were divided into the following categories: