Delta Levee work

Photo courtesy of the Delta Protection Commission 

Last week, the Delta Stewardship Council (DSC) held a public hearing to review proposed changes to how spending decisions on the maintenance of Delta levees are made, and the plan — known as the Delta Levee Investment Strategy (DLIS) — has drawn criticism from several sources.

Last week, the Delta Stewardship Council (DSC) held a public hearing to review proposed changes to how spending decisions on the maintenance of Delta levees are made, and the plan — known as the Delta Levee Investment Strategy (DLIS) — has drawn criticism from several sources.

Among the criticisms leveled at the DLIS is a concern that Delta towns, including Discovery Bay and Rio Vista, were ranked second among the three risk classifications, and heritage towns like Courtland, Hood, Walnut Grove and Locke received the lowest risk classification. Meanwhile, it’s asserted by critics like Deirdre Des Jardins, principal with California Water Research, that islands and tracts related to the export of Delta water via the State Water Project received the highest prioritization.

“Shifting state taxpayer funds to pay for improvements to Sherman Island and Twitchell Island from Rio Vista, Discovery Bay and North Delta legacy towns may not increase water supply reliability and may have significant impacts on small businesses, life and property in the Delta,” wrote Des Jardins in a letter to the DSC.

Urban levees in West Sacramento and Stockton did receive top-tier prioritization, as did Bethel Island — a fact Des Jardins noted in a blog post where she called investment in those areas “important.”

There are, according to the DSC, approximately 1,100 miles of levees in the region defined as the Delta. The levees play a critical role protecting homes, businesses, agricultural areas, historical landmarks and the state’s water delivery infrastructure from flooding. The area is also home to more than 500,000 residents. A catastrophic levee failure could result in a loss of life, property damage and a disruption of water supplies, in addition to other possible consequences.

“The Delta Reform Act (of 2009) created the Delta Stewardship Council and laid out some directives that we were to accomplish,” explained Erin Mullin, senior water resources engineer with the DSC. “We were to write the Delta Plan, and the Delta Plan was to accomplish a certain set of goals. One of those was to set priorities for state investment in Delta levee maintenance, operations and improvements.”

DSC documentation states the frequency of levee failures has diminished over the past 30 years, but at the time the Delta Plan was approved, the state did not have a comprehensive method to prioritize discretionary spending on flood risk management to ensure the spending was in line with the state’s long-term objectives. An interim methodology was put in place in 2013 while the DLIS was developed.

With the adoption of the DLIS in April 2018, the DSC developed a three-tiered risk assessment, and 144 islands and tracts were ranked as either “very high,” “high” or “other priority” to “ensure that the limited public funds available are expended first for improvements that are most critical to protect lives, property and state interests.” The plan further directs the Department of Water Resources — the state agency responsible for funding and completing the work related to levee maintenance and flood management — to fully fund each higher-priority objective before projects with a lower priority can be addressed. The DLIS identified 17 islands and tracts as very high priorities, and work on the remaining 36 high-priority and 91 other-priority properties would be prohibited until funding for the 17 very-high priority parcels is secured.

“The prioritization is a risk-based assessment,” said Mullin. “The way that we defined risk is the probability of flooding times the consequences of that flooding. We looked at the estimated levee fragility for each of the islands and tracts, and we looked at the state interests on each of the islands and tracts. There was an analysis done to see what is the threat to state interests on each island and tract. That was how we set the prioritization, based on the highest risk to state interests.”

The rigidity of the DLIS process is a source of concern for some critics of the plan.

“The concern that our commission continues to have is that the approach doesn’t fully appreciate the system-wide nature of Delta levees,” said Erik Vink, executive director of the Delta Protection Commission. “We’re not saying that every last segment is critical to the strength of the entire network, (but) it’s pretty close to that. It can be a real challenge to start to disregard levee segments, especially as it relates to prioritization of improving those levees. The more we learn about what happens when levees breach in the Delta, the more we realize we don’t know how the entirety of the system works.”

Vink went on to argue that all Delta levees should be improved to a base level of protection, and only improvements beyond that should be subject to prioritization.

“We will now have a prioritization scheme that puts most of these levees in a low-tier priority, so they won’t enjoy any money for improvement until levees in a higher segment are improved,” said Vink.

The plan took about four years, and Mullin said that DSC hosted over 70 workshops and public meetings in the Delta and with Delta interests. Though the DSC adopted the recommended DLIS last year, an additional process is required because regulations in the Delta Plan are legally binding. For that reason, additional analysis and review is required, and that process added more than a year to the plan’s timeline.

“It was a deliberate, iterative process that was taken step by step,” said Mullin. “The next steps are that we’re going to be considering the public comments, developing responses to the comments, and taking it back to the council for their direction. We have a year from the time that we file our regulatory package on July 5th to wrap the process up. Hopefully, we’ll be doing it much quicker than that. I don’t anticipate that it will go beyond the next few months.”

Despite DSC’s effort, Barbara Barrigan-Parrilla, executive director of Restore the Delta, feels the plan places emphasis on water exports over Delta communities.

“We believe that the council cannot fulfill its legislative directive to protect the Delta as a place of cultural, economic and historical significance, if it fails to promote policies that protect human life and the totality of the Delta communities,” wrote Barrigan-Parrilla in a letter to the DSC. “The failure to prioritize the protection of human life reduces the Delta to nothing more than a water extraction zone.”

For more information, visit the Delta Stewardship Council at, the Delta Protection Commission at, California Water Research at and Restore the Delta at