Center for Marine Biodiversity and Conservation

Due to its arid, Mediterranean climate, lack of rainfall and scarce supplies of local water, Southern California relies on the northern half of the state and the Colorado River to satisfy most of its water needs. As demand rises due to population growth and economic expansion, Southern California’s reliance on imported water from the Colorado River and the Sacramento-San Joaquin Bay-Delta is beginning to show signs of uncertainty from drought, reallocation of water for the endangered Delta Smelt and other Colorado River Basin states a declining snow pack that has left reservoirs at their lowest levels in ten years. In an effort to increase the reliability and decrease the scarcity of future water supply, many water agencies are considering ocean desalination as a response strategy. Once an expensive alternative, recent advances in technology, coupled with increases in the cost of imported water, have made ocean desalination more economically viable. While ocean desalination offers a drought proof and reliable supplement to existing water supplies, its unique environmental impacts, energy requirements and social costs are cause for concern. Therefore, this document has been developed to educate the public about the process, costs, benefits and environmental impacts of ocean desalination. It may also serve as a template for regional water planners that wish to compare ocean desalination with other water management strategies.