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This article is a sidebar to Comstock’s feature story on flood protection in Sacramento. 

As bad as the flood risks are in Sacramento, they might be worse in Stockton.

Like Sacramento, Stockton has two major rivers — the San Joaquin and the Calaveras — that converge in the city. Like Sacramento, Stockton’s rivers can overflow because of winter storms and Sierra snowmelt, factors that experts say are increasing with climate change.

Stockton differs from Sacramento in one key area: the quality of its flood-protection system. Stockton’s levees haven’t received a major overhaul since the 1990s, while Sacramento’s have received widespread upgrades in the last 20 years.

“We think they’re in danger,” says Jane Dolan, chair of the Central Valley Flood Protection Board. “They’re behind on flood protection.”

Chris Elias, who until recently served as executive director of the San Joaquin Area Flood Control Agency, says Stockton’s flood risks are “possibly worse” than Sacramento’s. 

“Sacramento has had billions of dollars invested in flood protection,” he says. “Stockton has not.”

The government has spent $5.5 billion on major flood-protection projects in the Sacramento area in the last two decades, according to the state Department of Water Resources. In the Stockton area, the government has spent $1.4 billion, all in the last four years.

Flood protection projects are funded by federal, state and local governments, with the majority coming from the federal government.

Residents have a voice in the process by voting on property-tax increases to pay a portion of the local share.

Elias notes that residents in his district have agreed to tax themselves for flood protection work. “That’s huge — it shows the seriousness of the threat,” he says.

Construction has started on levees on the Lower San Joaquin River and will “fortify our flood-protection system in North and Central Stockton,” Elias says. 

Those areas, which include the confluence of the San Joaquin and the Calaveras rivers, are Stockton’s highest-risk areas, he says.
The work is half complete and expected to be done in seven years, according to the state.

The last reported state inspections in the Central Valley, in 2022, found levees throughout the Stockton area failed to meet the standard expected under state law — protection against a 200-year flood. Most of Stockton is in the 200-year floodplain, Elias says, with the westside facing the greatest risks.

South Stockton and nearby suburbs are not receiving flood-protection improvements under the current construction work. That area has substantial risks, as evidenced by flooding in 1997 that led to non-mandatory evacuations.

When it studied what work was needed in the Lower San Joaquin River basin, the U.S. Army Corps of Engineers excluded the area known as the Mossdale Tract. The agency said such work would encourage development in a floodplain.

Parts of the Mossdale Tract are already seeing significant development. Lathrop, located at the southern end of the tract and along the San Joaquin River, was the fifth-fastest growing city in the country in 2023. 

Despite federal resistance to flood-control improvements in the Mossdale Tract, state and local officials are moving forward with plans for the area and hope to convince the federal government to join them, Elias says.

The work is included in the state’s flood-protection plans, completed by the Central Valley Flood Protection Board, and the plans from the San Joaquin Area Flood Control Agency. Voters agreed to fund the local portion of the work in 2020, and assessments started last November. 

“We have also continued our work with the state and USACE to complete an evaluation to determine federal interest and investment to achieve more protection for the area,” Elias says.
USACE did not respond to requests 
for comment.

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