The Salton Sea: An introduction to an evolving system and the role of science

Abstract

While the Salton Sea was a relatively stable ecosystem for most of the 20th century, recent agricultural-to-urban water transfers have caused significant impacts on the region's ecology, including the expected loss of all fish and the fish-eating birds that are reliant on them. Photo: California DWR. The Salton Sea, located in Southern California, is a saline terminal lake that has had many identities over the past century or so. Since its reincarnation in 1905 due to lower Colorado River flooding that partially refilled the Salton Sink, it has been California’s largest lake by surface area, covering approximately 350 square miles (Water Education Foundation 2001). In the second half of the 20th century, it was referred to as one of the most productive fisheries in the world, drawing more than 1.5 million annual visitors in the 1960s — more than visited Yosemite National Park at the time — the majority of whom were there for fishing (Cohn 2000; Harris et al. 1969). Throughout the 20th century, with a habitat that supported over 400 species of migratory and resident birds and served as an important stopover along the Pacific Flyway, the Sea warranted recognition as one of the premier bird watching locations in the United States, if not the world (CNRA 2006; Cowan 2014; Schwabe et al. 2008). Yet with nearly 90% of its inflow comprised of agricultural drainage waters from the approximately 500,000 acres of irrigated farmland in the Imperial Irrigation District (IID), and exposure to an extremely arid climate that results in excessive evaporation (~ 1.3 million acre-feet annually), the Sea’s natural attractions have faded as the lake has become more polluted and nearly twice as saline as the ocean (Fogel and Schwabe 2021; Lyons and Hung 2021). Such an outcome was not unexpected given that while the Sea has played many roles in the past, its most well-known if not primary role from a management and water rights perspective has been as a “reservoir for irrigation drainage” (Littleworth and Garner 2017, p. 256). With the passage of the 2002 Quantification Settlement Agreement (QSA) — a local-state-federal