The Salton Sea, located in Southern California, faces a significant environmental challenge. Once a popular resort destination, this large inland body of water has become increasingly toxic, posing serious threats to the environment and nearby communities. Understanding its unique origins and contributing factors is important for addressing its current state.
The Sea’s Unnatural Origins
The Salton Sea did not form naturally. Its modern existence began in 1905 when an irrigation canal from the Colorado River breached. For two years, floodwaters flowed uncontrolled into the Salton Sink, a dry basin, creating California’s largest lake.
Since its formation, the Salton Sea has been sustained primarily by agricultural runoff from the Imperial and Coachella Valleys, along with inflows from local rivers. It functions as a terminal lake, meaning it has no natural outlet and water leaves only through evaporation. This characteristic leads to the accumulation of substances within the sea.
The Accumulation of Contaminants
The primary reason for the Salton Sea’s toxicity stems from continuous agricultural runoff. Irrigation water carries pesticides, herbicides, and fertilizers into the sea. These chemicals, including nitrates and phosphates, accumulate, contributing to eutrophication and algal blooms. Additionally, banned substances like DDT have settled into the lakebed sediments.
The lack of an outlet and high evaporation rates lead to extreme salinity. The Salton Sea is now significantly saltier than the Pacific Ocean, more than double seawater’s salinity. This increasing salt concentration further concentrates pollutants and makes the environment unsuitable for most aquatic life.
Agricultural runoff also mobilizes naturally occurring toxic elements from the soil, such as selenium, arsenic, and lead. These elements, present in ancient lakebed sediments, are leached by irrigation water and accumulate. Selenium, for instance, can be highly toxic in elevated concentrations. Metals like cadmium, copper, molybdenum, and zinc have also been found at elevated levels.
Ecological and Environmental Consequences
Rising toxicity and salinity severely impact the Salton Sea’s ecosystem. Fish populations, like tilapia, experience massive die-offs due to high salinity and depleted oxygen. Algal blooms further reduce oxygen as they decompose.
These fish die-offs affect migratory birds that rely on the Salton Sea as a crucial stopover along the Pacific Flyway. Avian botulism outbreaks occur when birds consume infected fish or maggots. This causes significant bird mortality, including thousands of pelicans and other fish-eating birds. Other diseases like avian cholera and salmonellosis also contribute to bird losses.
As the Salton Sea’s water levels decline, large areas of contaminated lakebed, known as playa, become exposed. Strong desert winds pick up this fine dust, carrying toxins and particulate matter into the air. This windblown dust poses significant respiratory health risks to nearby communities, which experience higher rates of asthma and other breathing problems. The dust contains chemicals and carcinogens, and the region’s air quality is among the worst in the nation.
Challenges and Restoration Efforts
Addressing the Salton Sea’s environmental crisis presents significant challenges. The vastness of the area, high cost of solutions, and complex political dynamics make remediation difficult. Balancing agriculture, environmental protection, and community health is an ongoing struggle.
Despite these difficulties, efforts are underway to manage the shrinking sea and mitigate its impacts. The Salton Sea Management Program (SSMP), led by California, aims to construct habitat and dust suppression projects on exposed lakebed. Projects include creating wetlands and ponds to provide habitat for birds and fish, and implementing dust suppression measures. Federal and state funding has been allocated to these long-term endeavors, with the goal of improving air quality and restoring critical habitats around the sea.