OAKLEY, Calif. (CN) — The Sacramento-San Joaquin River Delta faces significant challenges affecting the health of its waterways and ecosystem, and stewards say state agencies must accelerate efforts to prepare for the impacts of climate change and a growing urban landscape.
Delta Stewardship Council staff presented the Delta Plan Five Year Review on Thursday, recommending numerous measures to preserve precious water and environmental habitats against future crises such as extreme drought, sea level rise and earthquakes.
The council recommended that stewards work with state regulators to improve the delta's ecosystems and reduce reliance on delta water, and with landowners to identify affordable uses of sinking land for sustainable farming.
The 70–square mile watershed known as the Sacramento-San Joaquin River Delta is the largest freshwater estuary on the West Coast and one of the Golden State’s most prized natural zones. Levee failure is one of the greatest challenges facing the complex region due to seismic risk and sea level rise, council officers Jeff Henderson and Martina Koller said.
Many of the delta’s 1,100 miles of levees date back to the 1800s and protect more than 600,000 residents and about 740,000 acres of land.
Levees which meet state or federal standards protect only 30% of delta islands and tracts — leaving 70% of land reliant only on banks that fall short of U.S. Army Corps of Engineers standards. Although climate change will intensify current risks, the funds to accelerate levee improvement are short, Randall Neudeck of the Metropolitan Water District said.
“We aren’t breaking even on these islands,” Neudeck said. “We are looking at new programs in the future to try to get sustainable revenue sources on the islands.”
Cash flow also affects projects to slow land subsidence. The state has finished only 10% of the 30,000 acres of planned subsidence reversal and carbon sequestration projects within the last decade, the council reported.
On the bright side, management of the delta’s water is improving, the council said.
State and federal pumps move water from Northern California reservoirs south, helping supply more than two-thirds of Californians with drinking water. Much of that water travels through the delta, irrigating the millions of acres of agriculture that produce about 45% of the nation's fruits and vegetables.
The council also reported that between 2010 and 2020, urban water users reduced consumption by 20%. More than 90% of urban suppliers who rely on delta exports can handle at least three consecutive dry years.
However, the delta’s ecosystems are still struggling, affecting salmon and smelt populations in the waterways. Despite work to restore more than 5,300 acres of tidal wetlands and 700 acres of riparian habitat, the delta battles toxicity from both ongoing and emerging contaminants and increasing levels of harmful algal blooms.
While nitrate contamination levels in groundwater wells have improved, arsenic contamination has not, according to the council. Between 2014-2022, delta waterway segments not meeting water quality standards increased by 30%.
“Attention should be focused on water wells that serve small water systems and disadvantaged communities," the council said in their report.
The council is also looking toward transforming land use to increase carbon capture and storage. For example, Neudeck said one island which grows corn has switched to rice crops, to help slow land subsidence while earning carbon sequestration credits.
“These aren't money making ventures, but we’re trying to make it so it’s sustainable,” he said.
Those who attended the report presentation focused their concern on earthquakes and flooding. Gilbert Cosio, owner of River Delta Consulting, said levee improvements must be a high priority in the face of natural disasters.
“It’s a lot of money, and the funding is not what we’d like it to be,” Cosio said. “I spent my whole career working on the levees, and now I’m semi-retired and they aren’t fixed yet.”
Deirdre Des Jardins, director at California Water Research, cited University of California, Los Angeles climatologist Daniel Swain’s finding that a doubled chance of a “great flood” should drive the state’s haste to make improvements.
“I know it’s been incredibly challenging to get the funding to upgrade levees for a 100-year flood event,” Des Jardins said. “I think it could cause an extreme loss of life, particularly in the primary delta.”
Californians can comment on the report for 45 days. Councilmember Diane Burgis, supervisor of Contra Costa County's Third District, said that hearing from a diverse number of communities with stake in the delta’s future is key. Those who live and work along the 57,000 acres of waterways have a long history of debating management of levees, land and ecosystems.
“So many of these communities are still trying to catch up with the infrastructure required and expected of them,” she said. “At the same time, there’s all these other challenges happening and I don’t think we recognize that enough. The challenges we’re facing are not unique to California — it’s international.”
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