Science and policy dilemmas in the management of agricultural waste waters: the case of the Salton Sea,CA, USA

The Salton Sea in California, a repository for agricultural drainage water and sewage effluent from the United States and Mexico, is increasing in salinity and may soon be too saline to support fish and other elements of the present food chain. Massive fish kills and bird die-offs in recent years have led to a perception that this is an ecosystem in trouble, and an initiative to restore the Salton Sea is underway. Engineering proposals to stabilize the salinity and volume of the Salton Sea could cost a billion dollars or more to install and ten million dollars per year or more to operate, and could adversely affect adjacent ecosystems, with no certainty that the problems of the sea would be remedied. On the other hand, allowing salinity to increase will likely lead to a dramatic change in the species composition of the sea over the next two decades. We consider the possible ecological consequences of allowing salinity to increase in the Salton Sea to levels similar to other salt lakes in the region. We also consider the possible adverse ecological affects of engineering proposals which would discharge contaminated Salton Sea water into the Gulf of California or divert excess Colorado River water that now flows to the Colorado River delta to the Salton Sea. We consider the benefits of an alternative proposal, which would handle the problem within the Salton Basin by installing designed wildlife habitats around the Sea while allowing the main body to become hypersaline. We recommend a set of principles which should guide policy decisions regarding restoration of the Salton Sea.