Sacramento Delta at flood stage, 2009. (Credit: By Doc Searls (Flickr: 2009_03_06_sfo-bos_066) [CC BY-SA 2.0)
From the outside, it’s easy to believe that the controversy that embroils the California Water Fix is more about incongruent perspectives, in that many of the technical proponents of the Fix and its opponents seem to be talking at cross purposes. There can be little doubt that the issue of water in California—which touches upon shortages, drought, access between regions, agriculture, environmental impact, cost, conservation, and of course water quality—is so complex and divisive that it’s difficult to imagine that any one solution would resolve all issues for all stakeholders.
However, it’s possible that the technical experts, many of them engineers, who devised the Fix, were approaching the issue in a different way than are most of the people now debating it.
The Sacramento-San Joaquin Delta is at the heart of California’s water disputes, where battle lines are most fervently drawn. This 720,000-acre maze of canals and islands encircled by levees at the epicenter of the California water system was once freshwater marshland. The entire region was an estuary, moving in rhythm with the Pacific, east and west as salty water moved inland during drier days, only to be flushed away by freshwater seasonally.
When settlers came, they engineered California’s water system to move north to south, providing the water-poor areas in the Central Valley and Southern California with the ample water from the north. They achieved this goal by damming rivers and pumping water from the delta, moving it all the way down to Los Angeles, climbing over mountains to get there. Thanks in part to these machinations, the agriculture in the Valley flourished, and people continued to stream into Southern California.
However, while planners projected that the water would be enough to sustain the goals of every stakeholder in the 1960s, the time of the State Water Project, that amount of water never materialized. Droughts came with increasing regularity, stressing the entire system. Farmers planted crops like almonds, thirsty for huge amounts of water, and irrigated more fields.
Meanwhile, the estuary felt more pressure, water levels dropped, and the tides changed as the massive pumps changed the face of the Delta and trapped various species of fish, already in danger from dropping water levels. The Delta smelt and winter-run Chinook salmon are now endangered, creating another stakeholder in the region: federal actors charged with protecting the species.
And more and more people came.
Particularly since the recent drought years, almost everyone in the region of the Delta has an opinion about who is to blame for water scarcity. Many farmers blame the need to protect fish species. Many in the cities blame a host of problems from immigrants to lawns. Conservation groups cite insufficiently aggressive recycling and water conservation practices. And few of these groups support the California Water Fix.
Dr. Jonathan P. Stewart is a professor of geotechnical engineering, earthquake engineering, and engineering seismology and the Chair of the Department of Civil and Environmental Engineering at the University of California, Los Angeles. He is not directly involved with the California Water Fix projects. However, he has been researching technical issues in the Delta for a decade, mostly related to the seismic stability and seismic hazard of the levees specifically, and the broader seismic hazard in the region.
“The overarching concerns that we’ve been tasked with investigating by the Department of Water Resources is when we have an earthquake in that region, we expect to lose a lot of levees, which will lead to flooding of the interior islands,” Dr. Stewart details. “That flooding will necessarily involve water from the bay coming into the Delta in an uncontrolled way. Once the saltwater from the bay comes in there, it compromises Clifton Court, which is the intake for the California water projects, and then you no longer are able to export water to all the places served by that project which includes Contra Costa County, most of the West Valley area, including Coalinga, and of course Southern California. That’s the big concern.”
In other words, while there’s no doubt that the issues under discussion by these other groups are important, they may not really be at the crux of what makes the California Water Fix important: it is a measure to prevent what would be a large-scale disaster in the event of an earthquake in the region.
“My sense is that the single biggest motivation for the water fix project as outlined by the governor is to try to avoid that scenario, because once that scenario plays out, it’s very, very difficult to recover,” explains Dr. Stewart. “You can’t just flush the system out with fresh water very easily. There is no source near Clifton Court. So it’s very difficult to recover.”
What would the Delta look like immediately after a seismic event—and then as the aftermath unfolded?
“The day after an event where these levees failed and the islands flooded, you’d have lakes in the interior of the islands, and the levees that are still intact around the sides would have water up against them,” Dr. Stewart describes. “The problem is that those levees, while they have erosion protection on the side that’s supposed to be up against the water, do not have erosion protection on the side that’s supposed to be dry. So soon as you get a little bit of wind, you get wave action against the unprotected sides of levees causing erosion. Even if you start fixing the parts of the levees that failed from the earthquake, new failures will almost certainly develop over time due to erosion.”
There would also be no way to send water to the Central Valley for agricultural uses or Southern California.
“You would have communities all up and down the West Central Valley, not to mention big parts of southern California and Contra Costa County, that would have significantly reduced access to water,” Dr. Stewart adds, until it was all repaired. Meanwhile, ongoing failures would continue to happen, and the entire process would be astronomically expensive.
Experience has already shown that fixing the levees is costly. In June 2004, a mere 350 feet of levee broke near Stockton, allowing the Middle River to flood crops and homes. The reasons for the failure are still unknown. The cost to repair that relatively small breach was $90 million—and that’s just the cost of the levee, not the repairs to homes, farmland, and other damages.
“In the case of damaging earthquake, the repair problem is compounded by the need to repair not one, but multiple levee breaches, as well as the subsequent breaches from erosion. This is an enormous challenge, and very costly. Moreover, even if that could be accomplished, there is the matter of flushing saltwater out of the southern Delta to re-establish fresh water at Clifton Court. We would be well advised to avoid this scenario by developing effective mitigation strategies before the earthquake occurs.”
Moreover, in the days following a flood in the Delta, the impact of the loss of the water would be felt even beyond those areas in the state that would immediately be without water. For one thing, the rest of the country is dependent upon California’s abundant agriculture, which includes more than one-third of the nations’ vegetables and two-thirds of the nations’ nuts and fruits.Furthermore, the water from the Delta has a much greater impact than its volume implies.
“The impact of the California Water Project is actually greater than is immediately apparent just by its own flow rate,” Dr. Stewart details. “The Project is delivering water that is of relatively high quality in terms of low salt content. In fact, it exceeds some quality standards so it is blended with Colorado River which is often of lower quality, due to higher salt content prior to distribution.”
In other words, as important as the California Water Project water is in its own right, its impact is far greater than its volume, because it allows officials to use Colorado River water without salt removal.
“If you lose the California Water Project water you lose those cubic feet per day, but then you also have a problem with the Colorado River water,” Dr. Stewart states. “You either have to send it out into the distribution system with a higher salt content than is recommended, or you have to devise some way to treat that water. If the saltier water is distributed, there are implications for pipes, networks, and human health.”
Some opponents to the Fix simply do not accept that there is a real seismic hazard in the area. This is, of course, incorrect.
“I’ve been to meetings in the delta where people argue, “I’ve been living here for 50 years and I’ve never felt an earthquake, so therefore there’s no risk,” Dr. Stewart comments. “And that’s a pretty easy argument to refute.”
Other opponents of the Fix, including some engineers, have argued that the risk is minimal based on the nature of the faults.
“I’ve heard engineers argue that the faults that are driving the hazard are not of the type that can really produce earthquakes,” reports Dr. Stewart. “While they will correctly point out that high-activity sources like the Hayward fault or the San Andreas fault are relatively distant, they fail to recognize the hazard from relatively proximate, but still active faults.”
However, in 2014 the Napa Fault, which is similar to those near the Delta, did rupture and cause an earthquake. Its magnitude was 6.0, and two years later, damage was still being addressed.
“It so happens that, the Napa Fault has a similar slip rate, which is how quickly the two sides of the fault displace relative to each other over time, to some of the local faults.,” Dr. Stewart explains. “Other aspects of the faults are also similar in several cases, such as their approximate dimensions. As a result, if the argument is that the faults local to the Delta cannot produce earthquakes, by extension the Napa fault also could not produce earthquakes—yet that is what occurred in 2014. A colleague and I discussed this in an editorial in The L.A. Times. In summary, we have known faults in the region—this is typical of California, we’re not talking about Kansas here—and as a result we should expect earthquakes to occur in the future.”
And while some critics argue that money should be spent on repairing levees instead of constructing tunnels, there are technical reasons why the levees will probably never be able to withstand an earthquake.
“These levees are vulnerable,” cautions Dr. Stewart. “Many levees are comprised of liquefiable soil. That means that earthquake shaking can cause the material to develop high water pressures, and temporarily have virtually no strength, causing it to behave almost like a liquid. As a result, a levee that’s standing with a slope can start sliding, and you lose some portion of the levee height, causing flooding
Looking back at the history of the Delta, concerned voices who feel humans have engineered this problem to begin with may not be wrong. This mess was caused by damming and pumping the region into a completely different ecosystem, so why should we continue to try to engineer solutions? And how could we ever have the right, especially when the tunnels may well shove multiple species into extinction?
The answer, at least for Dr. Stewart and others, is a practical one: the people are here now, and so is the risk.
“These faults, they’re capable of earthquakes up to magnitude 6, maybe at the outside magnitude 6 and a half,” Dr. Stewart says simply. “We know that faults like that can rupture, though they may not rupture in your lifetime or mine, they could go in hundreds of years or they could rupture tomorrow. We have these faults near the Delta and so we in the earthquake community are pretty confident that this area has a genuine seismic hazard. Is it as high as Oakland or San Francisco or L.A.? Of course not. But it is there, and we would ignore it at our peril.”