"In the 1800s there was a lot of earthquake activity in the Delta. But after 1906 there's been a lull," said Les Harder, deputy director, California Department of Water Resources. "It's fairly well agreed upon that the Delta has enjoyed a quiet seismic period, and that's not going to last. Tectonic movements continue in the Bay Area. The faults are due to break again. We'll expect to see larger earthquakes."
Five days after Harder spoke those words, a 5.6-magnitude quake hit near San Jose. Harder was speaking at the Oct. 25 meeting of the Delta Vision Blue Ribbon Task Force, which is preparing recommendations for saving the Delta to be presented to Gov. Arnold Schwarzenegger later this year.
There is a 62-percent probability of a 6.2-magnitude or larger earthquake in the next 25 years in the Bay Area, said Harder. There's a 28-percent chance that the levees on 30 or more Delta islands will fail simultaneously in that same time period due to a large quake. The west side of the Delta (the portion nearest East County) is expected to be hit harder than the eastern portion.
"The levees are relatively fragile for earthquake shaking," said Harder. "They are not designed for this. (Economic losses) could be as much as $60 billion for a catastrophic event."
Delta Task Force member Raymond Seed, who is a professor of civil engineering, said that unlike the isolated break in a levee that has been seen in the past, an earthquake would cause massive levee failures.
"Some of the seismic scenarios would require us to construct tens of miles, if not hundreds of miles, of levees," said Seed. "It would be like starting over. Putting a few rocks in place is not going to stop the channels. We may need dredges where we can literally rebuild levees almost from scratch. It's a task we should set for ourselves. It's not a simple issue."
It will cost anywhere from $25-52 million per mile of levee to make them seismically safer, so the tab could be enormous. As a result, choices may have to be made on which islands are most worth saving.
"The Delta is a place that has a value in itself and should be protected as the jewel that it is," said Harder. "(But) we don't have the funds to protect every single thing. (The emphasis will be on) some of the towns that are there, populations that are there and other points of value - which islands have people, habitat, and are critical for infrastructure. There's a fair amount that we want to retain. It's probably very much in the billions of dollars."
Currently nowhere near that amount of money is available. Proposition 1E, the $4 billion Disaster Preparedness and Flood Prevention Bond approved by voters last year, may provide at least $500 million for Delta levee protection, with another $300 million available from other sources. Reclamation districts can tap into those funds, receiving 75-percent reimbursement for levee repairs. About $57 million is being spent this year on levee repairs in California.
A proposal has been made to spend up to $74 million to stockpile rock and make other preparations to more quickly shore up levees in case of an earthquake.
Ron Baldwin of the San Joaquin County Office of Emergency Services told the task force that it's important to put together a regional agency that will be in charge of the Delta when an earthquake occurs.
"Regional is a buzzword that everyone supports until you try to implement it," said Baldwin. "We need a regional response system where we're integrated and have a single organization responding. The prime directive is to hold the levees. If we hold the levee, we prevent a lot of tragedy. The real vision is: how do we get there? How do we overcome those barriers of turf?"
Linda Fiatt from the Delta Protection Commission said a group is forming to discuss how to transport people and animals off of the islands in case of levee failures.
"I was watching the media about the fires (in Southern California) and seeing the kids in the stadium with their goats and pets. If you ask people to leave their animals (behind in an emergency), they won't do it. We're going to talk about what currently exists out there and where the gaps are."
To publicize and personalize the situation, Baldwin suggested creating a contest in which schoolchildren provide names for the levees.
Phil Isenberg, a former state assemblyman who once represented far East County and now chairs the Delta Task Force, jokingly suggested these two names: "Death and Destruction Levee" and "About to Fail Levee."