Salton Sea

• 1. Introduction

  ›

  The surface of the Salton Sea lies 236 feet below sea level, as measured in January 2018. Its deepest point sits only 5 feet above the lowest point in Death Valley. This landlocked lake in Southern California covers 318 square miles, according to a 2023 report. That makes it the largest lake in the state by surface area. Nothing drains out of it, so water leaves only by evaporating in the desert heat.

  The lake exists because of an engineering mistake. Since its birth it has survived on leftover water from farms. That arrangement turned a desert playground into a shoreline of dead fish, bad smells and toxic dust. This documentary follows the Salton Sea from its prehistoric ancestors through its resort glory to today's scramble to save it. Along the way it asks who caused the trouble, who is breathing the consequences, and what might still be done.

  8956346820

• 2. Ancient Lake Cahuilla

  ›

  Three million years of Colorado River mud explain why the Gulf of California ends where it does. Without the river's delta, the gulf would reach as far north as the city of Indio, roughly 150 miles beyond its present limit. Through the Pleistocene, the delta grew until it sealed off the northern part of the gulf. Since then the river has swung back and forth. Sometimes it emptied into the basin and made a freshwater lake. Sometimes it ran to the gulf and left the basin to dry into desert. Wave-cut shorelines at different heights record this cycle across hundreds of thousands of years.

  The most recent freshwater lake was Lake Cahuilla, also called the Blake Sea after the geologist William Phipps Blake. It covered over 2,000 square miles, six times the area of the Salton Sea. Radiocarbon dates and archaeological sites show that it filled three or four times in the last 1,300 years.

  Each time the water returned, people came to its shores. Hundreds of sites have turned up, some perhaps long-term villages and others temporary camps. The residents ate at least four kinds of fish, including razorback sucker and bonytail chub. They also hunted coots, jackrabbits and cottontails, and sometimes deer and bighorn sheep. Their plant foods and materials included bulrush, cattail, mesquite and saltbush. The Cahuilla people keep an oral memory of the last lake, which existed in the 17th century and dried up soon after 1700.

  Long before any new sea arrived, the dry bed of the Salton Sink hosted a major salt-mining operation.

  25136

• 3. The Canal Blunder

  ›

  Mapmakers struggled to name the basin long before it held any water. The Spanish-era name was the Colorado Desert, after the river. A railroad survey completed in 1855 called it the Valley of the Ancient Lake. Old maps in the Library of Congress label it Cahuilla Valley, after the local tribe, and Cabazon Valley, after Chief Cabazon. Salt Creek first appeared on a map in 1867. Salton Station shows up on a railroad map from 1900, although it had been a rail stop since the late 1870s.

  In 1900, the California Development Company, under Governor James Budd, began building canals to carry Colorado River water into the dry Salton Sink. Farmers soon planted crops there. Within two years, silt from the river clogged the Alamo Canal, and engineers could not clear it. Imperial Valley farmers were under heavy financial stress and pressed the company for a fix.

  Engineer Charles Rockwood faced bankruptcy. After what the record calls "mature deliberation," he directed workers to cut a breach in the riverbank about 4 miles south of the wooden headgates known as the Chaffey Gate. The cut, called the Lower Mexican Intake, had no headgates of its own. It also had no permission from Mexican authorities. Rockwood's order was later described as a "blunder so serious as to be practically criminal."

  Then came 1905. Heavy rain and snowmelt swelled the river, which overran the third intake cut into its bank and poured into the Alamo Canal. The flood spilled down two formerly dry arroyos, the New River to the west and the Alamo River to the east. Each is about 60 miles long. Over about two years, those two channels carried the entire volume of the Colorado River into the Salton Sink.

  The Southern Pacific Railroad dumped earth into the headgate area, but the effort was too slow. The river cut deeper into the desert sand and formed a waterfall that chewed its way upstream along the canal's path. It began at 15 feet and reached 80 feet before the flow through the breach was stopped. Engineers feared it would climb all the way to the river's true channel, where it might grow to between 100 and 300 feet and become nearly impossible to stop.

  The rising water drowned the railroad siding at the town of Salton and the New Liverpool Salt Company facility with its miniature railroad. It also swallowed much of the Torres Martinez Desert Cahuilla Indian Reservation, established in 1876. Nearly half of the reservation flooded, and the Cahuillas packed their belongings and headed into the mountains. The breach was finally closed on the 11th of February 1907, after major intervention by the Southern Pacific. With no drainage out of the basin, the new sea's survival now depended on what farmers sent downhill.

  813151916

• 4. Boom and Bust

  ›

  By the 1920s, the Imperial Irrigation District was delivering large volumes of Colorado River water to valley crops. Flood irrigation was common, so plenty of runoff drained into the lake and kept it full. The district holds senior rights to the river under the Doctrine of Prior Appropriation. That rule gives whoever first puts water to beneficial use the right to keep using that quantity. Hoover Dam later ended the valley's intermittent floods, and Imperial Dam, built in 1938, now removes silt from water entering the canals.

  A wildlife refuge was set up in 1930 on wetlands along the shore that had drawn many birds. Fish thrived in the lake and fed massive flocks of migratory birds. Birdwatchers flocked to the refuge in the middle of a desert.

  Speed was another draw. Beginning in the late 1920s, powerboat racers came to the lake. A January-February 1950 issue of National Motorist magazine called it the fastest body of water in the world, citing low barometric pressure and dense water. The magazine got the physics backwards. The region's extremely low altitude actually brings higher air pressure, which helps internal combustion engines. Rival courses first attacked these advantages as unfair. By the mid-1930s the Salton Sea racing group had the backing of the National Power Boat Association. Races ran at Desert Beach every year from 1941 to 1951. From 1961 through 1965, the Salton City 500 endurance race drew drivers such as Mickey Thompson and the astronaut Gordon Cooper. Racing returned in 2008, when a sprint boat set new world records at Salton Sea Speed Week.

  The US Navy made a preliminary inspection of the sea in January 1940. By October 1942 the area was commissioned as the Naval Auxiliary Air Station Salton Sea, later known as the Salton Sea Test Base and run by Sandia Labs. It began as a seaplane base. Over the years it also tested plane-launched rockets, jet-assisted takeoffs and inert atomic weapon test units. It tested the parachute landing systems for the Project Mercury space capsule as well. The base was abandoned in 1978.

  In the 1950s and 1960s, hotels, yacht clubs, homes and schools rose along the shore. Stocked fish drew anglers, and visitors came for water skiing and boating. Resorts in Bombay Beach hosted Frank Sinatra, The Beach Boys and Bing Crosby. At the peak, more than 1.5 million people visited each year.

  Hurricane Kathleen in 1976 put Bombay Beach completely underwater. Heavy tropical storms in the late 1970s had already pushed up the water level and damaged towns and businesses, many beyond repair. Tourism dropped sharply, and many resorts were abandoned. The state began issuing odor advisories as the lake started to stink. The US Geological Survey chose four words for the smell: objectionable, noxious, unique and pervasive.

  732322277

• 5. Salt and Wildlife

  ›

  By 2019 the Salton Sea carried about 70 grams of salt per liter, double the Pacific Ocean's 35. Measurements from November 2024 ranged from 68,000 to 86,000 milligrams per liter, according to the 2025 annual report of the Salton Sea Management Program. The concentration has been climbing at roughly 3% per year.

  Farm water explains much of it. The Imperial Valley has about 500,000 acres of farmland, most of it flood irrigated. Water is diverted from the Colorado River near Yuma, Arizona, into the 82-mile All-American Canal. The canal runs west along the Mexican border and then north into 1,700 miles of channels. Gravity carries the runoff down the New and Alamo rivers to the lake. That water holds salts, selenium and nitrate fertilizers, and it leaches ancient salt deposits from the soil on its way. Desert evaporation concentrates it further. About 3.6 million tonnes of salt are deposited in the valley each year, and with no outflow the lake has no natural way to stabilize.

  Fertilizer runoff also feeds large algal blooms and raises bacterial levels. Salt water carries less oxygen than fresh water, and blooms and summer heat strip out even more. Fish suffocate and wash up on the beaches in mass quantities.

  The desert pupfish is the sea's only native fish and a federally listed endangered species. It survives anywhere from freshwater to water twice as salty as the sea, and it has adapted to the farm drains. The lake began as freshwater and was stocked with tilapia, gulf croaker, orangemouth corvina and sargo. By the 1960s rising salinity threatened some of them. A September 2019 report said the sea held some 100 million fish 20 years earlier, and more than 97% of them are gone. Introduced tilapia tolerate salt and pollution best, yet their numbers have fallen too low to sustain the fish-eating birds. As tilapia dwindled, their prey, the water boatmen, multiplied. Fish have also kept mosquito production low, and a loss of fish could change that. Mosquitoes in warm regions can carry West Nile virus, Western equine encephalitis and St. Louis encephalitis.

  Milt Friend of the Salton Sea Science Office called the sea a "crown jewel of avian biodiversity." More than 400 bird species have been documented, and the lake is a major rest stop on the Pacific Flyway. A December 2018 report from the National Geographic Society said nearly all of California's eared grebes stop there, along with at least a third of North America's white pelicans.

  During a four-month stretch in 1996, avian botulism killed 14,000 birds, nearly 10,000 of them American White Pelicans. Storms churned the lake, and botulism spread among dying tilapia that the birds then ate. An incinerator burned the carcasses 24 hours a day for weeks. News coverage boiled this down to a simple story of a toxic catastrophe, with water that could be deadly. By 2017, birdwatchers reported that most of the American white pelicans, double-crested cormorants and eared grebes had disappeared.

  One visitor still arrives. The Salton Sea is the only part of the United States with a significant population of Yellow-footed gulls, a species otherwise native to the Gulf of California, and most are present only in summer.

  6979862887

• 6. Toxic Dust

  ›

  After 1999, the shoreline began pulling back from stranded boat docks, homes and businesses. Local farmers were using water more efficiently, so less runoff reached the lake. In 2003, the Imperial Irrigation District signed the largest agriculture-to-urban water transfer agreement in US history. Under the 45-year Quantification Settlement Agreement, much of its allocation goes to coastal communities, including those served by the San Diego County Water Authority, at a profit. Farmers installed sprinklers in place of flood irrigation, along with soil sensors that tell them when to water. To meet the cuts, about 36,000 acres, roughly 10% of the valley's arable farmland, was temporarily left fallow. As the sea shrank, it became saltier than the ocean.

  The valley's farms grow alfalfa, wheat, carrots and Brussels sprouts. Alfalfa is the most widely planted crop, followed by Bermuda grass and Sudan grass. A third of the hay is exported to China, the United Arab Emirates, Saudi Arabia and Japan. Most of it feeds dairy cows, while Japan uses it for Kobe beef.

  The 2003 deal required the district to send extra mitigation water to the sea for 15 years. In 2014, the district and Imperial County petitioned the State Water Resources Control Board to act. The Pacific Institute warned of a "period of very rapid deterioration." On the 1st of January 2018, the mitigation period ended and 40% less water began flowing in. A court decision also ended a program that had capped and evenly shared members' water. The level fell faster. A one-foot drop exposes thousands of feet of bare lake bed, known as playa, and at least 75 square miles will be exposed by 2045.

  That exposed playa feeds clouds of toxic dust. A haze of pesticides, exhaust, factory emissions and lake-bed dust regularly hangs over the valley, and Imperial County became known for some of the worst air quality in the country. More than 20% of children in the region have asthma, while the national rate is under 10%. Ten Imperial Valley schools fly green, yellow and red flags to signal air quality. On a red day, children stay inside all day. Parents can also get emailed alerts from the Imperial County Air Pollution Control District.

  About 650,000 people, many of them farmworkers, live where exposure to the dust is significant. The most affected area is 85% Latino, and local activists ask whether this is a matter of environmental justice. The dust travels far. In 2012, residents of the Los Angeles Basin, some 150 miles away, complained of odor after a storm churned the biomass on the sea bottom. In 2022, a massive haboob rose during a nighttime storm with 60 mph winds and reached as far as Los Angeles.

  To hold dust down, the district plows furrows on newly exposed playa that it owns, a program called vegetation enhancement and surface roughening. The Imperial County Air Quality Management District, the South Coast Air Quality Management District, the University of California at Riverside School of Medicine and the group Comite Civico Del Valle run mobile and fixed monitors. Scientists are still working out how much of the region's asthma the lake dust causes and what the windblown particles actually contain.

  9337383525

• 7. Rescue Plans

  ›

  Congressman Sonny Bono pressed for attention to the sea in 1995. After his death in a 1998 skiing accident, his wife Mary Bono Oswald and other politicians took up the cause as a tribute. Congress passed the Salton Sea Reclamation Act of 1998, and President Bill Clinton signed it. The Department of the Interior prepared a draft environmental report with the Salton Sea Authority. Studies piled up, including a Strategic Science Plan and an appraisal of alternatives from the Bureau of Reclamation. Then the September 11 attacks in 2001 shifted priorities away from the lake before the recommendations were put in place.

  The Imperial Irrigation District approved the 2003 water transfer only after Governor Gray Davis signed the Salton Sea Restoration Act. That law stated the "intent of the Legislature that the State of California undertake the restoration of the Salton Sea ecosystem and the permanent protection of the wildlife dependent on that ecosystem." In 2007 the state released an $8.9-billion proposal with a horseshoe-shaped outer lake, a berm across the center, and a web of dikes, channels and pumps. Lawmakers found it too expensive, and the Great Recession hit. Repeated delays and fading public interest followed.

  Importing seawater has been discussed for a long time. Around 2004, Aqua Genesis Ltd proposed over 20 miles of pipes and tunneling to deliver 1,000,000 acre-feet of water a year to coastal cities. Geothermal power would desalinate it. In 2018, the California Natural Resources Agency received 11 proposals to send more water to the sea, costing from $300 million to several billion dollars. A 2020 research report argued that moving water from agricultural users to the sea would cost less and use existing infrastructure. In 2022, a state-appointed panel rejected the aqueduct idea for its high cost, environmental damage and minimal benefits to Mexico. It recommended diverting fresh water instead, though the Colorado River itself faces what it called an unprecedented water crisis.

  Governor Jerry Brown's administration formed the Salton Sea Task Force in 2015. In March 2017, the Natural Resources Agency released the Salton Sea Management Program. It called for 29,800 acres of habitat and dust-control projects on lake bed exposed by 2028. The state initially budgeted $80.5 million to start designing wetlands, with a projected total cost of $383 million. The goal had shifted from restoring the lake to presenting a plan lawmakers could fund gradually. Since 2000, California voters have approved five bond measures, which supply nearly all of the state's money for these projects.

  The first state-funded project was the Torres-Martinez Wetland Project, finished in April 2018. The Torres Martinez Desert Cahuilla Indians partnered with the state to restore shallow wetlands on the northern edge that a massive 2012 storm had destroyed. In November 2019, an emergency was declared over the heavily polluted New River. In February 2020 came the 112-acre Bruchard Road Dust Suppression Project, the first dust project completed under the management program.

  Construction began in January 2021 on the 4,110-acre Species Conservation Habitat Project at the mouth of the New River. Its ponds and wetlands mix lake water with river water to control salinity and selenium. That blend creates the right conditions for the desert pupfish and other aquatic life. The federal government said in November 2022 that it would spend $250 million over four years. In October 2024, a further 750 acres were announced, backed by $70 million in federal drought funding. In 2025, water began flowing into the first 2,000 acres of the shallow ponds.

  3049664359

• 8. Heat, Lithium, and Art

  ›

  Between 1 and 3 kilometers below the lake, a geothermal brine reservoir holds fluids at 250 to 380 degrees Celsius. The brine carries lithium at about 202 parts per million, far more than the Dead Sea's 30 to 40. It also holds rubidium, caesium and bromine. Geothermal plants stand along the southeastern shore, and a Berkshire Hathaway Energy subsidiary operates 10 of them in the area. The California Energy Commission estimates the field might produce 600,000 metric tons of lithium carbonate a year. One account says the nearby reserve amounts to roughly a third of global supply. Several groups want the new interest in lithium to help pay for restoration.

  The Salton Buttes are volcanoes in the same geothermal field. On the eastern side of the sea, mudpots and mud volcanoes bubble, including the mobile Niland Geyser. The lake also serves a practical purpose, since it is used to calibrate sensors on imaging satellites such as Landsat.

  The basin sits over the San Andreas, San Jacinto and Imperial fault zones. Geologists have linked earlier Colorado River flooding episodes to earthquakes on the San Andreas Fault. While Lake Cahuilla was full, earthquakes above magnitude 7 struck roughly every 180 years, the last within decades of 1700. A risk of a magnitude 7 to 8 quake remains. Simulations show that a rupture running north from the south would shake the Los Angeles area harder than one running south. Around the sea itself, increased seismic activity and soil erosion are breaking down roads. Bridges on Highway 86 routinely separate from the pavement.

  Bombay Beach has been reinvented since 2011 as a destination for desert art. South of the sea lie Niland and Slab City, where artists created East Jesus and Salvation Mountain. Niland had a population of 1,006, and a fire in June 2020 displaced 112 people. A news item in April 2018 described Bombay Beach as enjoying "a rebirth of sorts with an influx of artists, intellectuals and hipsters who have turned it into a bohemian playground." The 2016 dystopian film The Bad Batch used the area as its wasteland.

  The sea has long drawn filmmakers and musicians. Roger Corman said his story for the 1954 film Highway Dragnet came from a trip to the sea. In The Monster That Challenged the World, from 1957, giant prehistoric mollusks lurk at the bottom of the lake. Michael Jackson filmed the video for In the Closet there in 1992. Linkin Park shot photographs for Minutes to Midnight near the ruins of North Shore Beach and Yacht Club in 2007. The Alamo Sea in the 2013 video game Grand Theft Auto V is based on the lake.

  The earliest of these was Curtis Harrington's dreamlike 1949 short film On the Edge, which made extensive use of the bubbling mudpots. In a 1971 interview he said: "The location I used is entirely covered by water now; the sea has risen to cover it."

  99100742411