California’s Salton Sea is retreating at a greater rate, according to balloon mapping study

The Salton Sea, California’s largest lake by surface area, is experiencing an increased rate of shoreline retreat following policy changes to shift more water from the Colorado River to San Diego, according to a new study. . As a result, the lakebed has dried up, producing more polluted dust from dried agricultural runoff, impacting nearby communities, the researchers said.

Researchers predict that, given current rates of retreat, parts of the Salton Sea’s North Shore are expected to retreat 150 meters by 2030 and a further 172 meters by 2041.

The average retreat rate increased from 12.5 meters per year from 2002 to 2017 to nearly 38.5 meters per year since 2018. “Without mitigation measures, the expansion of exposed playas around the Salton Sea is expected to further exacerbate community exposure to pollutants,” the study states.

The study was conducted as a community science program involving local youth and other residents, using balloon mapping to record images of the coastline.

“This study is a direct response to requests from our community to participate in an impactful research agenda to understand shoreline reduction,” said Ryan Sinclair, Ph.D., MPH, associate professor of environmental microbiology at Loma Linda University. said. in Public Health and principal investigator of the study. “Local residents want to live next to the Salton Sea, something they can be proud of.”

Sinclair said balloon mapping can cover a larger area compared to using drones, which need to be recharged.

The study was published last week in the journal Geographries. Authors of the study included students, LLU faculty, Alianza Coachella Valley staff, and researchers from the University of California, Riverside.

Located in the eastern Coachella Valley of Riverside and Imperial counties, the Salton Sea has expanded and contracted in size over the centuries. The lake’s water levels currently rely heavily on agricultural return water from the nearby Imperial Valley, a vast agricultural region that holds significant water rights from the Colorado River diversion. The valley receives more water than Nevada and Arizona combined.

Sinclair said the flow of water from the Colorado River to the region has decreased in recent decades following changes to water rights agreements in 2003, and starting in 2018, water sent to San Diego will be reduced. It is said that the amount has decreased further due to an increase in the amount of Defenders of the Salton Sea are at war with a number of long-standing water shareholders across Southern California, Nevada, Arizona and Mexico. Shareholders include cities, settlements, farms, tribes, and recreational areas.

Agricultural runoff into the Salton Sea brings pollutants such as hydrogen sulfide, which become entangled in the dry lakebed and associated dust.

Sinclair and community members spent many days between 2019 and 2021 creating a series of maps using a balloon equipped with a camera suspended 60 meters above the coast. The researchers compared their findings to satellite images from 2002. They now hope the results will become part of efforts to restore the lake’s capacity.

“We started this at a strategic time,” Sinclair said of the study, which began shortly after policymakers diverted higher water rates to San Diego starting in 2018.