We Must Do More to Protect Water Supply

The tragedy in Turkey was not that there was an earthquake; severe quakes are to be expected in seismically active areas. The tragedy is that public officials did nothing in the face of knowledge that the infrastructure, including residential housing and water delivery systems, was not built to withstand the inevitable.

But are California’s infrastructure planners doing much better in the face of credible information about earthquake vulnerability? Take, for example, the state’s water supply system. A report released last December by Cal-Fed, a consortium of state and federal agencies charged with addressing California’s water problem, suggests that the risk of an earthquake resulting in the failure of California’s water supply system is alarmingly high. Specifically, the report predicted a 15% chance of catastrophic levee failure in the crucial Sacramento-San Joaquin Delta area in the next three decades, or 25% within the next 50 years. Those are the odds in Russian roulette; only the seriously suicidal would play them.

More than 20 million Californians and the state’s $14-billion-per-year irrigated agricultural industry rely on water pumped from the delta, which is actually an estuary of the Pacific Ocean that extends inland almost to Sacramento. The pumps are at sea level, and the barrier that keeps these pumps from being contaminated with seawater is a network of “islands” surrounded by man-made earthen levees.

But this delta region is seismically active, and it is inevitable that the levees will eventually fail in an earthquake. This problem is exacerbated by the fact that that these islands already are 10 feet to 20 feet below sea level and sinking one to two inches every year. When the delta levees fail, saltwater from San Francisco Bay will flood the existing water supply system until a new system can be built, which would take years.

The death toll from delta levee failure would probably be low, but the economic disruption and corresponding human misery may exceed any previous preventable calamity in California. Catastrophic levee failure could not be repaired and would halt operation of the state water project for months or years, stranding the multibillion-dollar economies dependent on this water in the Silicon and San Joaquin valleys and Southern California. Inundation of the delta with saltwater would also permanently destroy its use for agriculture and its value as habitat.

Cal-Fed’s report on delta levees also concluded that the current government plan to spend $1 billion to strengthen them will not appreciably reduce the likelihood of their failure, because the problem is not the vulnerability of the levees themselves but the ground on which they stand.

Where are California’s infrastructure planners and politicians on this issue? For five years, Cal-Fed has been engaged in a planning process, costing more than $50 million so far, to secure a sustainable future for the delta and its water and environmental resources. A casual observer therefore might expect that addressing the seismic vulnerability of the delta would be the centerpiece of the emerging plan. But there is little mention of that risk in Cal-Fed’s report and no analysis of its implications for the plan that is being developed. At most, Cal-Fed seems willing to study the problem at some point.

Why does no one seem to care? Because the most obvious way to earthquake-proof the water supply system is to bypass the delta with a peripheral canal, an intractable issue that remains beyond the politically possible in California. Delta farmers and many environmental groups that oppose the canal do not wish to give succor to canal supporters. Canal supporters do not wish to be accused of fear-mongering. The peripheral canal has stumped at least three previous governors, and the current one does not seem about to wade into this political quagmire.

Nor is a peripheral canal a panacea in any event. To be sure, it would provide a more secure future for water users that export water from the delta. But it would not protect California against the eventual collapse of the delta levee system. In that circumstance, hundreds of thousands of acres of farmland dependent on the delta as well as the delta’s own fragile ecosystem will be lost. Conversion of the delta to an inland sea would destroy tens of thousands of acres of key wetlands and forever preclude restoration of the delta ecosystem and the endangered species dependent upon it.

There is a way to protect the delta: California could physically rebuild the islands so that they are no longer dependent upon the integrity of the levees.

Before the islands were converted into agriculture, they were at sea level. After a century of agriculture, the peat soils out in the delta have literally decayed, and the land surface has fallen to between 10 feet and 20 feet below sea level. If we can restore these islands back to sea level, then levee failure is no longer a concern. We will protect not only California’s water system but also the delta environment and its current dominant land use, farming.

Rebuilding the key delta islands to sea level is no small task. It would require raising the elevation of 20,000 to 40,000 acres of delta islands by an average of 10 feet, which could cost billions of dollars and take decades.

But the alternative scenario that threatens California’s economy is unacceptable. California must figure out a way to move forward with some way to safeguard the delta’s water supply and ecological resources.

Scientists have begun testing techniques for rebuilding these islands, including reusing dredged materials from shipping ports, cultivating tule (wetland vegetation) to physically regrow delta soils, importing soil from other regions and capturing the millions of tons of sediment that flow through the delta each year. The initial studies are encouraging.

One thing is sure: We can’t prevent earthquakes. But we can mitigate the consequences of them on our infrastructure.

Will we force our children to cope with the economic and ecological disaster that could follow a major earthquake in the delta? Or will we pass on to them a delta that they can depend upon as a resource to sustain both the state’s economy and its natural heritage?