Flood risk is one of the most pressing threats to the Sacramento-San Joaquin Delta. The Delta’s 1,100 miles of levees protect highly productive agriculture, recreational assets, habitats for sensitive species, utility and road infrastructure, freshwater for export, and navigation. However, Delta levees are becoming more vulnerable in the face of sea level rise, extreme weather events, burrowing animals, and subsiding islands, as well as shifting priorities and funding gaps.
A panel discussion at the Delta Stewardship Council’s October meeting highlighted the need for ongoing levee maintenance and the economic challenges of maintaining levees.
“The coequal goals are built on a foundation of levees,” said Erin Mullin, Senior Engineer with the Delta Stewardship Council. “Without levees, we do not have a reliable water supply and our ecosystem would be changed in a way that I don’t think that any of us can even imagine.”
DELTA LEVEE HISTORY
Many of the levees date back to when the Delta was reclaimed for agricultural purposes, with most of the levees being built between about 1900 and 1920 by landowners after the advent of the clamshell dredger.
“As those levees were built, they would just take the mud from the bottom of the rivers and slap it up on the natural levees, or if they were trying to be more efficient, they would make straight lines rather than follow the actual natural levees in the Delta,” said Tom Zuckerman. “That’s important to understand because there are different geological circumstances underlying different sections of the levees. Some of them were built on established natural levees. Some of them were built over channels. Some of them were built over peat soil. And over the years, with the problems of dealing with reclamation and maintenance of these levees, the engineers have had to develop different techniques to deal with each of those situations.”
THE SUCCESS OF THE LEVEE SUBVENTIONS PROGRAM
The landowners mostly built the Delta levees, and it is challenging to maintain them as private owners. Each island has at least one public agency that takes care of the levees, called reclamation districts, or levee maintenance districts, established under state law.
“They usually just consist of the land behind the levee,” said Mr. Zuckerman. “Those districts tax themselves, and they levee assessments within their districts to pay their share of the levee costs. It’s a real limitation as to how much work can be done because oftentimes the district can’t raise enough money even to meet their share of the cost.”
Paul Hames / California Department of Water Resources
It wasn’t until 1973 that there was state assistance for levee maintenance through the Delta Levees Maintenance Subventions program which provides funding on a cost-share basis to local levee maintaining agencies for rehabilitation and maintenance of levees in the Delta. The Delta Levees Special Projects Program was established in 1988. Through the two programs, the state has spent approximately $500 million in the Delta for flood protection and related habitat projects.
Joe Countryman, Central Valley Flood Protection Board Member, said the Delta Levee Subventions Program is the most cost-effective infrastructure program the state has ever put forward. “They offer a carrot to the local landowners to tax themselves and improve and maintain the levee system,” he said. “We got bond money in 2006 and we spent $200 million in fixing and improving the levee system in the Delta. And I’m sure without that influx of money, the Delta would look nothing like it does now. There would be a lot more islands looking like Franks Tract out there.”
“For the last 25, maybe almost 30 years, as a result of the efforts that we’ve been able to undertake in the Delta with these programs, we haven’t had a major flood in the Delta,“ said Mr. Zuckerman. “If you look back historically, all of these islands flooded at least three times, some of them eight or 10 times prior to that time. So, as Joe said, this is probably the most successful infrastructure program that the state of California has undertaken. It’s been relatively cheap. It’s had the cooperation and the driving energy behind it from the landowners and the farmers in the area, which has kept the cost down and everything pretty reasonable. It’s a very good program.“
There’s a proposition on the ballot, Prop 4, which will put some more money into the levee program. Without that, the program would run out of funding. There is no stable source of funding for these programs.
Tom Zuckerman acknowledged it’s an expensive process for the landowners to maintain these levees, and the economy of the Delta has not been great.
“The levees are what the Delta is. There’s no going back. If we start to lose one levee, we’re going to lose the one next to it, and then the one next to that, because of the pressures that are generated from wind, fetch, and so forth. It is a system, and we need to maintain it all at a reasonable level. Some of the levees protect more important things than others, and oftentimes, there’s another financial pool to help maintain those levies to a higher standard, but it’s very important that we have a reasonable standard, not only to deal with what we’re dealing with today but what we’re going to be dealing with as sea level rise increases.”
PROJECT AND NON-PROJECT LEVEES AND THE ROLE OF THE ARMY CORPS
The Central Valley Flood Protection Board is responsible for setting, maintaining, and enforcing standards for building, maintaining, and operating flood control systems and serves as the non-federal sponsor for federal flood control projects outlined in the State Plan of Flood Control. The State Plan of Flood Control includes both federally authorized and state-authorized projects along the mainstem and tributaries of the Sacramento and San Joaquin Rivers that have been built incrementally over the years, such as levees, weirs, bypasses, and other flood management infrastructure that are part of the federal-state flood protection system.
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The Delta Levees Investment Strategy (DLIS) is a risk-based prioritization for levee investments in the Delta with the goal of maximizing flood protection for people, property, water supply, the Delta ecosystem, and infrastructure.
Project levees are built to comply with the Army Corps of Engineers guidelines and are part of the federal flood control project. Of the Delta’s 1100 miles of levees, only about a third of those are the project levees. When a levee breaks in the Delta, only those federal project levees are eligible for federal funding to recover the island and rehabilitate the levee. So when a non-project levee fails, the state of California has to pay to recover the island at a cost of tens of millions of dollars.
Councilmember Ben Hueso asked about the possibility of putting more Delta levees into the Corps program, but Joe Countryman said that’s highly unlikely as the Corps must first determine it is economically feasible, meaning the economic benefits of the area being studied exceed the costs of the levee. The Corps has studied other islands in the Delta but has not found any additional levees that are economically feasible to bring up to the federal standard.
Erin Mullin added that the Army Corps doesn’t consider water supply as it’s not part of their mission, which is primarily navigation. “When they consider the cost benefit analysis of a levee, they do not look at its participation in the water supply for California. So if the levee functions as a water supply feature, it does not factor that into its function. That’s been one of the challenges we’ve had with engaging the Corps in finding a positive benefit-cost ratio in the Delta.“
Tom Zuckerman said the Army Corps’ policy is penny-wise and pound-foolish as the money FEMA spends responding to flooded islands is much more than what the state has spent on the subventions and special projects programs.
“We can maintain these levees and prevent almost all of the failures at a reasonable cost,“ said Mr. Zuckerman. “But when an island floods, you’re saying, is it worth is it worth it to reclaim it? We don’t have a lot of choice on a lot of those things because the levees not don’t just protect the farmland now; they protect the Deep Water Ship Channel, the transfer of water across the Delta to the Central Valley Project, and the State Water Project, the environmental values of the Delta, an enormous recreational economy and so forth. It’s difficult to just rely on the people within the island to maintain these levees that provide so many public benefits to the state, and that’s the reason why the state is sharing in the maintenance and costs.“
GOING FORWARD …
Mr. Zuckerman said there is a need for an agricultural standard for all of the levees in the Delta. “It is more than just maintenance because the situation is changing constantly. You build one, and it doesn’t just stay there. It can consolidate, it can erode, and so forth. So we’re constantly rebuilding them. We call it maintenance, but we’re trying to maintain it to a level that will withstand global warming and sea level rise and so forth. So, it’s not just a maintenance program. We need a program to get and keep all of the islands at a minimum level. It wouldn’t be foolproof, but will reduce the number of catastrophic failures down to something that we can manage.“
“The Achilles heel in the Delta is that there will be a levee failure there,“ said Joe Countryman. “There will be. There’s no doubt in my mind about that if you just consider all the probabilities and the state of the construction. There’s no way the local landowners can recover that island. It can only happen if they have federal and state help.“
