The Salton Sea is a shallow, landlocked, highly saline body of water in Riverside and Imperial
counties at the southern end of the U.S state of California.
It lies on the San Andreas Fault within the Salton Trough that stretches to the Gulf of
California in Mexico.
Over millions of years, the Colorado River has flowed into the Imperial Valley and deposited
alluvium, creating fertile farmland, building up the terrain, and constantly moving its
main course and river delta.
For thousands of years, the river has alternately flowed into the valley, or diverted around
it, creating either a saline lake called Lake Cahuilla, or a dry desert basin.
When the Colorado River flows into the valley, the lake level depends on river flows and
the balance between inflow and evaporative loss.
When the river diverts around the valley, the lake dries completely, as it did around
1580.
Hundreds of archaeological sites have been found, indicating possibly long-term Native
American villages and temporary camps.
The current lake was formed from an inflow of water from the Colorado River in 1905.
Beginning in 1900, an irrigation canal was dug from the Colorado River to the old Alamo
River channel to provide water to the Imperial Valley for farming.
The headgates and canals sustained a buildup of silt, so a series of cuts were made on
the bank of the Colorado River to further increase the water flow.
Water from spring floods broke through a canal head-gate diverting a portion of the river
flow into the Salton Basin for two years before repairs were completed.
The water in the formerly dry lake bed created the modern lake, which is about 15 by 35 miles.
The lake would have dried up, but farmers used generous amounts of Colorado River water
and let the excess flow into the lake.
In the 1950s and into the '60s, the area became a resort destination, and communities grew
with hotels and vacation homes.
Birdwatching was also popular as the wetlands were a major resting stop on the Pacific Flyway.
In the 1970s, scientists issued warnings that the lake would continue to shrink and become
more inhospitable to wildlife.
In the 1980s, contamination from farm runoff promoted the outbreak and spread of diseases.
Massive die-offs of the avian populations have occurred, especially after the loss of
several species of fish on which they depend.
Salinity rose so high that large fish kills occurred, often blighting the beaches of the
sea with their carcasses.
Tourism was drastically reduced.
After 1999, the lake began to shrink as local agriculture used the water more efficiently
so less runoff flowed into the lake.
As the lakebed became exposed, the winds sent clouds of toxic dust into nearby communities.
Smaller amounts of dust reached into the Los Angeles area and people there could sometimes
smell an odor coming from the lake.
The state is mainly responsible for fixing the problems, and California lawmakers pledged
to fund air-quality management projects in conjunction with the signing of the 2003 agreement
to send more water to coastal cities.
Local, state and federal bodies all had found minimal success dealing with the dust, dying
wildlife, and other problems for which warnings had been issued decades before.
At the beginning of 2018 local agencies declared an emergency and, along with the state, funded
and developed the Salton Sea Management Program.
After a slow start and some small projects, construction started on a $207 million project
in early 2021 on the delta of the New River, creating ponds and wetlands on the southern
shore of the lake.
under Governor James Budd, the California Development Company began the construction
of irrigation canals to divert water from the Colorado River into the Salton Sink, a
dry lake bed.
After the construction of these irrigation canals, the Salton Sink became fertile for
a time, allowing farmers to plant crops.
Within two years, the Alamo Canal became filled with silt from the Colorado River.
Engineers tried to alleviate the blockages to no avail.
In 1905, heavy rainfall and snowmelt caused the Colorado River to swell, overrunning the
third intake cut into the bank of the river and sending the flood into the Alamo Canal.
The resulting flood poured down the canal, and down two former dry arroyos, the New River
in the west, and the Alamo River in the east, each about 60 mm long.
Over about two years, these two newly created rivers carried the entire volume of the Colorado
River into the Salton Sink.
The Southern Pacific Railroad tried to stop the flooding by dumping earth into the canal's
headgates area, but the effort was not fast enough, and the river eroded deeper and deeper
into the dry desert sand of the Imperial Valley.
A large waterfall formed as a result and began cutting rapidly upstream along the path of
the Alamo Canal that now was occupied by Colorado.
This waterfall was initially 15 feet high, but grew to 80 feet high before the flow through
the breach was stopped.
Originally, the waterfall was feared to recede upstream to the true main path of the Colorado,
becoming up to 100 to 300 feet high, when it would be practically impossible to stop
the flow.
As the basin filled, the town of Salton, a Southern Pacific Railroad siding, and Torres-Martinez
Native American land were submerged.
The tribe's reservation now straddles the northern end of the lake.
The sudden influx of water and the lack of any drainage from the basin resulted in the
formation of the Salton Sea.
The geothermal activity below the Salton Sea loosens up lithium that can be mined.
Due to increased demand for lithium, which is crucial for electric-vehicle battery production,
the Salton Sea area is attracting attention, and the extraction of lithium is expected
to boost the local economy.
In July 2021, General Motors announced that it was partnering with Controlled Thermal
Resources to develop a combined lithium extraction and power generation facility in the Hell's
Kitchen geothermal field in the Salton Sea, employing a closed-loop process.
The brine will be extracted from the ground, with geothermal steam being used to drive
a turbine generating electricity, and reacting with the brine to separate the lithium hydroxide
and lithium carbonate used for battery production.
The California Energy Commission estimates the sea might produce 600k metric tons of
lithium carbonate per year.
Evidence of geothermal activity is visible.
The Salton Buttes are volcanoes in the geothermal field of the same name.
Mud pots and mud volcanoes are found on the eastern side of the Salton Sea, including
the mobile Niland Geyser.
The area is used for geothermal electricity generation, with plants located along the
southeastern shore of the Salton Sea in Imperial County.
In the 1920s, agriculture had boomed in the valley as the Imperial Irrigation District
delivered large quantities of Colorado River water to irrigate the crops.
The lake would have dried up naturally, but with flood irrigation being commonly used,
plenty of water ran off the farms into the lake and kept it full.
The district holds senior rights to water from the Colorado River according to the Doctrine
of Prior Appropriation, which is based on whoever first put the water to beneficial
use could continue to claim it.
In 1930, a wildlife refuge was established on some wetlands along the edge of the lake
that had attracted many birds.
The fish flourished in the lake and provided a source of food for massive populations of
migratory birds.
Birdwatchers flocked to this new refuge in the middle of a desert.
The continuing intermittent flooding of the Imperial Valley from the Colorado River ended
with the construction of the Hoover Dam.
The Imperial Dam, built-in 1938, serves as a desilting dam for water entering the irrigation
canals.
In the 1950s and into the 1960s, the communities expanded as the area's reputation as a resort
destination and sport fishery grew.
Hotels and yacht clubs were built on the shore along with homes and schools.
Resorts in communities like Bombay Beach hosted entertainers such as Frank Sinatra, The Beach
Boys, and Bing Crosby.
Yacht clubs held parties at night and golf courses provided recreation.
Many people came for boating activities such as water skiing and fishing as stocked fish
proliferated.
Lakeshore communities grew as vacation homes were built.
More than 1.5 million visitors visited annually at the peak.
The Salton Sea and surrounding basin sit over the San Andreas Fault, San Jacinto Fault,
Imperial Fault Zone, and a "stepover fault" shear zone system.
Geologists have determined that previous flooding episodes from the Colorado River have been
linked to earthquakes along the San Andreas Fault.
Sonar and other instruments were used to map the Salton Sea's underwater faults during
the study.
During the period when the basin was filled by Lake Cahuilla, a much larger inland sea,
earthquakes higher than magnitude 7 occurred roughly every 180 years, the last one occurring
within decades of 1700.
Computer models suggest the normal faults in the area are most vulnerable to deviatoric
stress loading by filling in the water.
Currently, a risk still exists for an earthquake of magnitude 7 to 8.
Simulations also showed, in the Los Angeles area, shaking and thus damage would be more
severe for a San Andreas earthquake that propagated along the fault from the south, rather than
from the north.
Such an earthquake also raises the risk of soil liquefaction in the Imperial Valley region.
The effective drainage divide that separates the Salton Sea from the Gulf of California
is about 30 feet in elevation and is located near Delta, northeastern Baja California State,
Mexico, south-southeast of Mexicali.
Past sea level rise may partially be responsible for the salinity of the lake, while potential
future changes in sea levels could occur.
However, other factors such as hydrothermal vents, diffusion of salt from minerals and
sediment, including concentrated brine, and evaporites are another contributor to salinity,
as is the recent lowering of lake levels raising the salinity, though sedimentary records show
the lake surface elevation reached levels 33 to 39 feet above world sea level in the
1500s.
The Salton Sea has a salinity of 44 grams of salt per liter of its water, greater than
that of the Pacific Ocean.
The lack of an outflow means the Salton Sea does not have a natural stabilization system;
it is very dynamic.
Fluctuations in the water level caused by variations in agricultural runoff, the ancient
salt deposits in the lake bed, and the relatively high salinity of the inflow feeding the sea
are all causing increasing salinity.
The concentration has been increasing at a rate of about 3% per year.
About 3.6 million tonnes of salt are deposited in the valley each year.
An updated report on the University of California: Imperial County website provided these specifics:
"Salton Sea salinity is about 44,000 mg/l, that is about 4.4% salt.
The amount of salts that are deposited in the Imperial Valley agricultural land with
irrigation water is about 4 million tons of salts annually.
To maintain crop productivities, an equal amount of salts must be leached from the root
zone".
Fertilizer runoffs have resulted in eutrophication, with large algal blooms and elevated bacterial
levels.
By the 1970s, the runoff which was full of salty chemicals led to a warning that the
salinity of the lake would no longer sustain wildlife.
By January 2020, the salinity of the Salton Sea was double that of the Atlantic Ocean.
Both the hypersalinity and presence of contaminants in the Salton Sea triggered massive die-offs
in the fish and avian populations; saltwater carries less oxygen than freshwater, which
was further depleted by algal blooms and by extreme temperatures during the summer period.
The lake continued to dry up, exposing more lake beds known as the playa, and sending
nearby communities clouds of toxic dust.
A haze incorporating pesticide plumes, exhaust fumes, factory emissions, and the vaporized
dust from the lake regularly hangs over the communities in the valley.
With a dense blend of ozone and particulate matter, Imperial County became known for some
of the worst air quality in the country.
Eastern Coachella communities have disproportionately higher rates of asthma and respiratory complications
because of high concentrations of contaminants in the air.
Scientists are studying how much of this is due to the Salton Sea dust and what is actually
in the windblown particles.
Ten schools in the Imperial Valley use green, yellow, and red flags signaling air quality
for the many children who have asthma.
Green means they join their friends on the playground, whereas red means they stay inside
all day.
Parents can also receive emailed alerts from the Imperial County Air Pollution Control
District.
Local activists ask if this is an issue of environmental justice since the area most
impacted is 85% Latinos.
Some 650,000 people, many of who are farmworkers, live where there is significant exposure to
the dust.
The public health impacts of continuing not to meet federal air quality standards include
the treatment of child and adult asthma, Cardiac Disease, lung cancer, and increased mortality
rates.
Lower concentrations of the wind-borne dust travel all the way into Southern California
and Arizona.
Residents in the Los Angeles Basin, some 150 miles away, complained about the odor that
drifted their way in 2012 after the biomass on the sea bottom was churned by a storm.
During the first 15 years after the sale of the Imperial water to San Diego County, the
Imperial Irrigation District has been required to put water into the Salton Sea to compensate
for the loss of agricultural runoff needed to replenish the sea.
As the 2017 deadline for ending the additional mitigation water approached, the district,
along with Imperial County, petitioned the California State Water Resources Control Board
in 2014 with a demand for state action to fulfill its obligation after years of delays
and unfulfilled plans.
Pacific Institute, an environmental think tank, was warning that the lack of replenishment
water was leading to a "period of very rapid deterioration."
The rapidly shrinking sea was a "looming environmental and public health crisis".
With the increased shrinkage, dust storms would increase and the rotten-egg smell would
reach the coastal cities more frequently.
Fugitive dust, consisting of very small particles suspended in air, is being studied to distinguish
between playa dust and desert emissions that are primarily made up of mineral dust from
soil.
The Imperial County Air Quality Management District, the South Coast Air Quality Management
District, and the University of California at Riverside School of Medicine along with
the environmental justice group Comite Civico Del Valle are using mobile and stationary
air quality monitoring units in the effort to protect the health of the nearby residents.