RIO VISTA, CA, Aug. 8 (U.S.): Charlie Hamilton hasn’t watered his vineyards with water from the Sacramento River since early May, even though it flows just meters away from his crop.
Near the south, the industrial city of Antioch in the Bay Area supplied its residents with water from the San Joaquin River for just 32 days this year, compared to nearly 128 days by this time in a wet year, the Associated Press reports.
They may be close, but these two rivers, central arms of California’s water system, have become too salty to use in places as drought continues in the state.
In dry winters like California just experienced, less fresh water flows from the mountains into the Sacramento River, the state’s largest river. This allows salt water from the tides of the Pacific Ocean to rush into the state’s main water center, known as a delta. They help provide water for two-thirds of the state’s 39 million residents and for farms that grow fruits and vegetables for the entire nation, and they play a major but sometimes underappreciated role in the state’s economy.
Droughts that scientists say are part of a drought in the western United States 1,200 years ago combined with rising sea levels are revealing the fragility of this system, forcing state and city water managers and farmers to search for new ways to stabilize their fresh water supplies. Delta’s challenges offer a harbinger of upcoming dangers to critical water supplies elsewhere in the country amid a changing climate.
Planners and farmers face the problem of salt water intrusion through a desalination plant, an artificial barrier and groundwater pumps. Those who cannot engineer their way out of the problem are left with a strong hope that things will change.
“We’re just trying to hold on and hopefully the water quality will improve,” said Bobby Costa, a farmer who has seen cucumber yields drop 25% this year compared to wetter years.
The delta is the largest estuary on the west coast of the Americas. It’s home to endangered species like Chinook salmon and delta stingrays that require certain water flows, temperatures, and mixtures of salts, as well as hundreds of square miles of farmland and the millions of people who live, work, and recreate in the area.
Other estuaries such as the Chesapeake Bay and within the Everglades do not play a significant role in providing water directly for drinking and agriculture. But these estuaries are also at risk of salt encroachment, causing problems for ecosystems, groundwater supplies, and other needs.
Farmer Bobby Costa stands in his cucumber field, on Thursday,
Giant pumping systems built more than half a century ago send Delta waters south to major urban centers like Los Angeles and massive agricultural operations. The further east the salt moves, the more vulnerable the water system becomes. The brackish water that infiltrates the system is not as salty as ocean water, but it is salty enough to make it undrinkable for some crops and for people.
“The ramifications of losing control of the delta are very serious,” said Jacob McCwerk, principal engineer at the state’s Department of Water Resources.
Last year, the state moved 112,000 tons of rock and piled it 30 feet (9 meters) deep in a major river in the delta to prevent salt water from getting too close to the pumps. This was the second time in the past decade that we needed the bulkhead. The Department of Water Resources installed it for the first time during the last drought in 2015.
It was only meant to be temporary, but plans to remove the barrier last fall were called off due to dry conditions, although a slit was cut to allow fish to swim through it. Officials still hope to get it out in November.
The state has asked the federal government for permission to build two more barriers north if drought worsens, arguing that it will be necessary to protect the water supply. In the long term, the state wants to build a massive tunnel that will move water around the entire delta, which officials say will make it easier to catch more during times of heavy rain and protect against the dangers of saltwater intrusion.
But defenders of the area worry that it’s just another solution that would leave farmers, fish, and people who depend on the delta’s waters high and dry.
While the bulkhead protects the pumps, it does little to help some interests within the delta that rely on fresh water before they head south.
Take Hamilton, for example, which rents about 50 acres of vineyards to grow wine grapes along the Sacramento River. The land is owned by Al Medvitz, who grows alfalfa and other crops on more than five square miles of land. The water they draw from the river has always been gradually affected, and they learned how to pump water from it when the tides are low and the salt content is low.
But since early May, Hamilton hasn’t been able to draw any water at all, even during low tide, because it’s too salty for grapevines. If he continues to use it, the edges of the leaves on the vine will first begin to burn and curl, and then fewer grapes can grow in each bunch, eventually rendering the crop unusable.
To avoid this, he extracts groundwater from a well above the property and passes it through a ditch down to the drip irrigation lines, a process that takes much longer. Owner alfalfa, which is used to feed cows, can tolerate higher levels of salt, so it can still drink river water even now.
The two men want state approval to build a small tank on the property to store fresh water for use in times of drought. If they have to resort to salt water more and more, it will damage the soil over time.
He said that Hamilton’s goal is “to have land that my children can grow”.
Others, like Costa, don’t have many options. About four square miles (10 square kilometers) of land is cultivated in the southern extension of the delta. He gets water from several rivers in the delta, delivered by an irrigation zone through a ditch on his property. This year, the water’s high salt content was evident, leaving white spots on the dirt in his fields and damaging the cucumber crop.
He sells the cucumbers to a company that turns them into pickles for use in Subway and other stores. His yield is down 25% this year, and a lot of the cucumbers he picks are quirky, which makes using them more difficult to pickle.
said John Herrick, general counsel for the Southern Delta Water Agency, which is responsible for protecting the area’s water supply.
Meanwhile, in Antioch, a city of 115 thousand people, officials are investing in desalination. Last year, things were so bad that the city couldn’t draw water from the river at all.
John Samuelson, city engineer and director of public works, said the plant will be the state’s first inland brackish surface water desalination plant.
Sweetening plants are often controversial; Earlier this year, the state rejected a proposal in Orange County that would draw water from the ocean. But the water in the delta is not salty, so it takes less energy to make it fresh. Samuelson said other Bay Area cities are reaching out to Antioch to learn more about their efforts as they consider their own options for stabilizing water supplies as climate risks grow.
“We just know that this problem will continue to get worse in the future,” Samuelson said. “We want to make sure we think ahead and solve the problem today.”