California's Largest Lake is Shrinking Three Times Faster Than Before
California's Salton Sea appears to be shrinking even faster than before.
The lake, which is the largest in the state by surface area at around 240,000 acres, has seen its shoreline retreating three times faster in recent years than before 2017, according to a new study in the journal Geographies.
Policies that have decreed more water be rerouted from the Colorado River to San Diego may result in the Salton Sea's shoreline retreating by just under 400 feet by 2030, and by an additional 564 feet by 2041, according to the researchers.
They describe how they studied balloon and satellite images of a section of the lake dating back over 20 years and calculated the rate at which the shoreline was receding over time. They found that while the lake had been shrinking every year since 2002—the first year in their data—the recession accelerated between 2017 and 2020.
"The observed rate of change was greatly increased during the period from 2017 to 2020. The average rate of change rose from 12.53 m/year (41.1 feet per year) between 2002 and 2017 to an average of 38.44 m/year of shoreline change from 2017 to 2020," the researchers wrote in the paper.
The Salton Sea is a large, shallow, saline lake in the Salton Basin, a desert area between the Imperial Valley and the Coachella Valley.
Historically, the Salton Sea has relied on agricultural runoff from nearby farms in the Imperial Valley for much of its water, as farmers used Colorado River water to irrigate crops, and the excess runoff would flow into the lake. The 2003 Quantification Settlement Agreement (QSA) increased policy focus on water conservation, resulting in less water being used in agriculture, so that more could be provided to urban areas like San Diego.
However, this meant that less water reached the Salton Sea, causing the lake to slowly shrink year by year. Additionally, in 2018, even more water was sent to San Diego, further limiting the inflow into the lake.
The Southwestern U.S., including California, has experienced prolonged droughts and rising temperatures, which cause more water to evaporate from the Salton Sea, worsening the effects of reduced inflow.
Over the years, the Salton Sea has become increasingly saline because it has no natural outlet, with water only leaving through evaporation, concentrating the salts and minerals left behind.
As the lake recedes, its bed is being exposed, which contains airborne particulate matter (PM), including hydrogen sulfide, chlorides and pesticides, as well as toxic metals such as arsenic, lead and chromium. This dust is carried by winds to surrounding communities, worsening air quality and causing respiratory issues.
"This research was a direct response to a request from the community, which wanted to be involved in impactful research questions to understand shoreline reduction," study co-author Ryan Sinclair, an associate professor of environmental microbiology at Loma Linda University School of Public Health, said in a statement. "The community wants to be able to live next to a Salton Sea that they're proud of."
Another study r ecently published in the journal Environmental Research found that children living close to the Salton Sea were increasingly experiencing issues with their respiratory health: 24 percent of children in the area have asthma, compared to the national rate of 8.4 percent for boys and 5.5 percent for girls
"These rural environmental justice communities are facing health consequences due to local dust events," author of the Environmental Research paper Jill Johnston, an associate professor of environmental health at USC, said in a statement. "The agricultural industry in Imperial Valley has used excessive amounts of water, but one of the impacts of water conservation is the shrinking of the sea."
According to the Geographies paper, the increasing rate of the Salton Sea's shoreline receding may result in more particulates being whipped into the air, worsening the effects of the lakebed on local communities.
"Without mitigation, the continued recession of the Salton Sea shoreline and the resulting increase in PM10 concentrations pose significant risks to the health and well-being of nearby communities," the researchers wrote in the paper.
"This could manifest as increased respiratory illnesses, such as the increased asthma prevalence that the area is already experiencing or more frequent school absences that will occur with increased respiratory issues."
Do you have a tip on a science story that Newsweek should be covering? Do you have a question about the Salton Sea? Let us know via J. E., Kamai, E., Barahona, D. D., Olmedo, L., Bejarano, E., Torres, C., Zuidema, C., Seto, E., Eckel, S. P., & Farzan, S. F. (2024). Air Quality and Wheeze Symptoms in a Rural Children's Cohort near a Drying Saline Lake. Environmental Research, 263, 120070.
