Central Valley, California - The Weather of the Future - The Weather of the Future: Heat Waves, Extreme Storms, and Other Scenes from a Climate-Changed Planet - Heidi Cullen

The Weather of the Future: Heat Waves, Extreme Storms, and Other Scenes from a Climate-Changed Planet - Heidi Cullen (2010)

Part II. The Weather of the Future

Chapter 7. Central Valley, California

At the end of the movie Pretty Woman, after Richard Gere has climbed up a fire escape and rescued Julia Roberts from the drudgery of the real world—we hear a baritone voice declare, “This is Hollywood, the land of dreams. Some dreams come true, some don’t. But keep on dreamin’.” It’s a classic Hollywood ending. Everyone is happy and full of hope for the future.

Hollywood may serve as the unofficial capital of dreams, but it’s certainly not the only place in the Golden State that lies within the realm of unreality. The Central Valley, where the Sacramento-San Joaquin Delta is located, represents a very different kind of dream for the future, a kind that many scientists have come to see as sheer fantasy.

In the Sacramento-San Joaquin Delta, the Sacramento and San Joaquin rivers converge into canals, levees, streambeds, marshes, and peat islands. With an area that spans about 24 miles east to west and 48 miles north to south, the Delta is the hub of California’s water supply system. The entire state—especially the rapidly growing and increasingly dry metropolitan areas, such as Los Angeles and San Diego to the south—depends on this very small area of land for its water. The dream is that the Delta will be able to supply enough clean, fresh water to help cities and crops increase forever, all without harm to the natural environment.


If this sounds too good to be true, that’s because it is. Those cities now stretch from San Francisco and Silicon Valley in the north to Los Angeles and Orange County in the south. And the crops, including alfalfa and corn, grow on a version of Fantasy Island. Many islands in the Delta are 15 to 20 feet below sea level and are protected only by increasingly fragile levees. The Delta was a good dream, a very American dream. And it even came true, for a while.

But today, the Delta has become an example of how complicated and costly it can be to sustain a dream, especially when global warming is a factor. California’s gold rush attracted a new generation of Americans who came west and saw endless possibilities. But endless possibilities and unbounded growth require infrastructure. And infrastructure comes at a cost, both for the economy and for the environment.

I recently spoke with an economist and an environmental engineer about the future of the Sacramento-San Joaquin Delta. Ellen Hanak, director of research at the Public Policy Institute of California (PPIC), and Jay Lund, an environmental engineering professor at the University of California-Davis, are part of a multidisciplinary team that includes biologists, economists, engineers, and a geologist. The team members are studying the Delta and attempting to salvage what remains of the dream. I spoke with Hanak and Lund about climate change and about two reports they had recently cowritten. The first report recognized that the Delta is in a crisis. The second report looked at ways to manage the Delta’s water while protecting the Delta ecosystem. Management strategies that attempt to satisfy the competing interests of the Delta’s economy and its environment have been discussed and debated for almost 100 years, and sometimes California’s version of the battle between the North and the South has resulted.

Engineers are taught to find optimal solutions to problems. As applied to the Sacramento-San Joaquin Delta, optimal means finding a balance between environmental and economic interests, and between agricultural and urban users of water. Optimal doesn’t mean perfect; it does mean that no one wins entirely. Fish will die and agricultural yields will decrease, but optimal means that the Delta will have a future. It also means writing a big check up front and making profound changes to the Delta landscape before Mother Nature or the climate makes its own changes for you.

“I’m not sure how it’s going to play out. A lot of people are working to make sure nothing happens in the Delta, or that things only happen their way,” says Lund.

The Central Valley stretches approximately 400 miles from north to south and is roughly the size of the state of Tennessee. Today, about 6.5 million people live in the Central Valley, which is considered the fastest-growing region in California. All the scientists I talked to when I was selecting the locations to write about in this book considered it a hot spot with regard to global warming.

The northern half is the Sacramento Valley, and the southern half is the San Joaquin Valley. The two halves meet at the Delta. California’s capital, Sacramento, is located along the Sacramento River’s banks. The rivers and their tributaries are harnessed by more than 100 large dams that produce the majority of California’s hydropower. The Delta is part Frankenstein’s monster, part natural wonder.

The Delta provides water for two out of three Californians, and for almost 4 million acres of farmland. At the Delta’s western edge lies Suisun Marsh, and at its southern end are two prominent examples of California’s water infrastructure: the Delta-Mendota Canal and the California Aqueduct. The canal and the aqueduct deliver water from upstream reservoirs and the melting mountain snowpack to cities and farms in every direction. The Delta is the hub of the state’s water supply because it serves as the transit point for water. Whenever the Delta shows signs of its original personality and moves from being a predictable freshwater conveyance system toward being a vast tidal marsh, every effort is made to push it back into place, by repairing levees, releasing water from reservoirs, or reducing water exports. Needless to say, a lot of dreams rest on the earthen walls of the suboptimal canals and levees.

And that’s the trouble with the Delta. Scientists say the canals and levees have become increasingly vulnerable to a catastrophic failure, whether it arrives abruptly in the form of an earthquake or slowly as the result of a rising sea level caused, in turn, by global warming. In any event, the scientists are nearly unanimous: the Delta is unsustainable.

At the start of the gold rush in the late 1840s, the levees provided a simple way to lock down the landscape and get more value out of the land. Lund, an expert on water resources in California, says, “If you look at the geological history of the Delta there was always a lot of variability.” Native species, such as the delta smelt, came to depend on that variability. But there are now 1,300 miles of levees in the Delta and Suisun Marsh—they form a longer stretch than the entire California coastline—and the Delta’s natural variability has been kept to an absolute minimum.

“The Delta is the direct result of rising sea level since the end of the last ice age,” Lund explains. “During the last ice age, the Delta was to the west of the Golden Gate Bridge. But starting about 10,000 years ago, as sea level rose, the Delta moved inland. About 6,000 years ago, the Delta arrived at its current location, where, for the most part, it was able to keep up with sea level rise by building marshes. Sediment accumulation in the Delta kept up with the slow rise by forming thick deposits of peat.” Peat is made of organic matter: decaying plants and animals that only partially decompose. This dead matter can’t get enough oxygen to break down completely, because everything is waterlogged. “It took 6,000 years for that peat deposit to build, as one layer of new plant material grew on top of previous layers of peat,” Lund says. Through this gradual process of flooding and rebuilding, a diverse, resilient ecosystem evolved. Then came the gold rush.

It was actually during the California gold rush that farmers stumbled on the Delta and struck their own kind of gold. The peat in the Delta was capable of producing excellent crops. But to farm the organic-rich soils, farmers first needed to drain the islands. After 6,000 years of continual flooding and rebuilding, the Delta was, for the first time, being pinned down. “This involved constructing levees around the islands, filling most tidal channels, and, most important, lowering local groundwater tables below crop root zones by constructing perimeter drains,” Lund explains. “When you’re located at the confluence of two major rivers, the dry period is when you want to grow your crops. And if you can keep the soil moist but not waterlogged all year long, then you’ve really struck gold.”

The Delta was a perfect spot to settle and farm. Its proximity provided easy access to the miners and markets, and its soil was beyond comparison. “And so these natural levees were formalized and the islands were dried out,” Lund explains. Today, the Delta grows more than 90 different crops, including wine grapes, pears, rice, corn, and tomatoes, producing more than $360 million annually in farm sales. But altering the landscape came at a price that has yet to be paid.

“The problem,” Lund says, “is that peat soils are meant to be waterlogged. When they remain dry for long periods of time, they lose their integrity.” So, every year you farm, you lose some soil. “Today, we’re farming on borrowed time,” Lund explains. “We’re mining the soil until the islands fail.” In just 150 years, about 6,000 years’ worth of peat has been eroded. It’s gone. By engineering the variability out of the system, we’ve attempted to pin something down that cannot be pinned down.

Pinning the Delta down also pushed it down, and so it is that much more vulnerable to earthquakes, flooding, and a rising sea level. When the levees were first constructed, no regulatory policies forced people to consider their impact on the Delta ecosystem. Farmers were doing their own engineering, and they were optimizing around just one quantity—agricultural yield. Hanak, the economist, explains, “Many of the water diversions upstream and within the Delta were made before the public demanded environmental protection.”

Levees built 100 years ago confined water to channels and transformed the Delta from marshland into dry islands of land available for human use. The Delta islands started sinking when the marshlands, the source of all the fertile peat soil, were first drained. And the sinking—the scientific term is subsidence—continues to this day. There are now seventy-four islands in the Delta. Most of them are below sea level, many by more than 20 feet. Subsidence also increases seepage into the islands, raises the likelihood of levee failures, and increases the costs and consequences of catastrophic island flooding. Take your pick: earthquakes, floods, a rising sea level, subsidence, and urbanization all contribute to the increasing likelihood of multiple levee failures. Scientists, not known for hyperbole, describe this as a catastrophic failure.

The Delta has far more in common with New Orleans than with Hollywood. You could argue that when the Delta experienced a major levee break in June 2004, cracks in the dream were also beginning to appear. A year later, when the devastating effects of Katrina bore down on the old, inadequate levee system in New Orleans, Hanak, Lund, and their colleagues saw an indication of the future of the Delta. However, they saw an earthquake, not a hurricane.

As Lund, Hanak, and other scientists who study the Delta watched Hurricane Katrina bear down on New Orleans, they felt compelled to prevent something analogous from happening in their backyard. Scientists had long warned of the fate that awaited New Orleans if its infrastructure was not improved to prepare the city for a major hurricane. But political apathy, and perhaps human nature itself, prevented these scientists from making much headway.

Approximately 2 million people in the Central Valley count on levees for flood protection. And the capital city, Sacramento, which is among the fastest-growing cities in the United States, is the major metropolitan area at the highest risk of flooding. The problem is that Sacramento’s infrastructure is inadequate; it doesn’t meet even the minimal federal standards. Conservative estimates of potential flood damage to the Sacramento area alone exceed $25 billion. Sacramento is, of course, just one city among many in the Central Valley. Actually, Sacramento is well upstream of the Delta, and its land is above sea level, so failure in the Delta is unlikely to flood major population centers. Nevertheless, if the Delta goes, it can take a lot down with it. In addition to flooding large areas of lower-value agricultural land, it would cripple the delivery of water to the San Francisco Bay Area, Southern California, and the San Joaquin Valley.

So the Delta is now a big fishbowl—a fishbowl not very good for the native fish. The Delta is the habitat of more than fifty species of fish, including 75 percent of the state’s commercial salmon catch. Today, the Delta supports what scientists kindly refer to as a highly modified ecosystem. Hanak explains, “We’ve engineered this system to the point where it’s a lot more vulnerable. The invasive species like the artificial things we’ve created. But we’re legally bound to protect the native species that aren’t adapted to the new Delta we’ve created.”

The Delta today is, in fact, a shadow of its former self. It resembles the Delta of the past only in that some of the original species, such as the delta smelt and chinook salmon, are still present. Invasive species, both plants and fish, now dominate the Delta’s riprapped channels and islands; native species, including the delta smelt, the longfin smelt, and salmon, to put it mildly, are struggling.

The recent sharp decrease in the population of several prominent Delta fish species was a red flag for conservationists, many of whom believe that the entire Delta ecosystem is on the verge of collapse. Two species have already gone extinct in the Delta: the Sacramento perch, which needs to be reintroduced; and the thicktail chub, which has been globally extinct since 1957. Six Delta fish species are heading toward extinction: the southern green sturgeon, the longfin smelt, the delta smelt, the winter run chinook, the spring run chinook, and the Central Valley steelhead. Two species are in decline: the splittail and the late fall chinook.

With regard to global warming, every place has its own counterpart of the canary in the coal mine. In the Central Valley, the canary is most likely the tiny delta smelt, a translucent fish about the size of a human finger. In the fall of 2004, routine fish surveys registered sharp declines in the delta smelt, and it was listed as threatened under the Endangered Species Act. The number of delta smelt found in 2008 was the lowest in forty-two years of surveys. Federal scientists say the delta smelt is on the brink of extinction; some biologists conclude that it may be gone by 2010.

When scientists say the Delta’s native ecosystem is collapsing, they mean it. A major factor contributing to the collapse is the pumps. These pumps are extremely powerful and can kill fish that get stuck inside them. In addition, the reduction of total outflow to the ocean and the disruption of natural flow patterns in what is now a complex network of channels in the Delta aren’t helping matters. The situation has gotten so bad that in December 2007, U.S. District Judge Oliver Wanger imposed pumping restrictions to protect the delta smelt. The courts imposed 30 percent reductions on the amount of water that can be exported from the Delta by state and federal water projects. This means that even if water is available, it may not be delivered. On March 5, 2009, the state’s Fish and Game Commission unanimously voted to list the longfin smelt, a relative of the delta smelt, as a threatened species under the California Endangered Species Act. The commission also voted to classify the delta smelt as an endangered species. (It had been listed as threatened since 1993.) The ruling to protect the environment has disrupted the water supply of much of the state.

The scientists concerned with the Delta hoped to do better than those who had been concerned with Katrina, by giving people a vision of what lay ahead. The title of their first report was Envisioning Futures for the Sacramento-San Joaquin Delta.1

“Back in the summer of 2005, I got in touch with these guys and we all agreed that someone needed to start looking at the Delta. It was a problem that required a multidisciplinary approach. There are so many moving parts,” Hanak explains. “It was clear the Delta required more sophisticated long-term planning. And after years of neglect, the Delta ecosystem was showing signs that it had become unhinged. The crash of some Delta fish species between 2004 and 2005 helped focus attention.”

Hanak says it was important to combine an economic perspective with an engineering perspective. “The way we try to look at it is that there are two primary objectives: water for humans and a healthy ecosystem for fish populations. If you do those two things … you might make the Delta more sustainable,” Hanak says. “We wanted to give people a look at possible futures. We thought that it would help people to think long-term. We can’t just tinker with the status quo.”

Ask any scientists who study the Delta and they will tell you that it is likely to change significantly and abruptly within the next generation. A sudden catastrophic change would be a very hard landing indeed for those depending on the Delta. When a system pinned for more than a century swings loose, it’s going to take a lot down with it. The scientists feel that their job is to help people see what a catastrophic failure would look like and then provide options to prevent the worst-case scenario.

The scientists might not be worried about a hurricane in the Delta, but they’ve got plenty of other scenarios that would result in a catastrophic failure. An earthquake and a flood are the two most likely scenarios, and both could take the levees out fairly quickly. According to recent calculations, the odds are roughly two in three that during the next fifty years either a large flood or a seismic event will affect the Delta. And the scientists say that these odds are a conservative estimate, for two obvious reasons. First, strain continues to accumulate on faults in the Bay Area, increasing the risk of seismic activity with each passing year. Second, the 100-year flood isn’t what it used to be, thanks to global warming. The estimate of what a 100-year flood event in the Delta looks like is based on outdated hydrology data that don’t adequately address the impact of climate change on the Delta. Scientists have already established that in recent years, climate change is causing much higher inflows from rivers feeding into the Delta.

When I asked Lund if it was fair to say that a catastrophic levee failure of some kind was guaranteed by the end of the century if nothing was done, he answered as any good engineer would: “Well, you can’t give it a 100 percent probability. But I might put it at 99 percent.”

Aside from the cause, the scientists see a lot of the same issues in the Delta that their counterparts had warned about with regard to Katrina. Lund and Hanak envision a levee failure that would directly threaten water supplies and affect thousands of roads, bridges, homes, and businesses at the same time.

An earthquake is the quickest way to take down the Delta, and even though earthquakes are geologic—not climate-based—events, the changing of the landscape through global warming will determine its resilience. It’s what scientists call an unavoidable threat, and it’s been on their radar for more than thirty years. There are at least five major faults close to the Delta, and these are capable of producing significant ground accelerations. The soils are poor enough and the levees weak enough that risk of failure due to liquefaction and settling is high. You can do a lot of seismic risk studies in thirty years, and all of them indicate a very high potential for major earthquakes in the region sometime in the near future. If there is a major earthquake—similar to the 1906 event in San Francisco, which measured 8.25 on the Richter scale—many Delta island levees will fail simultaneously. And with each inch of rise in the sea level, the cost of such a failure increases significantly.

Even in a scenario involving a moderate-magnitude (6.0) earthquake, the seismic risk studies show a potential for multiple levee failures. The highest risk is in the western Delta, which is very close to several significant seismic sources and is already characterized by deep subsidence and poor foundations. There is a medium to high risk of catastrophic levee failures for almost all the central Delta as well. Scientists working for the Department of Water Resources (DWR) recently modeled the consequences of a catastrophic levee failure caused by a large earthquake. In one of the scenarios, the earthquake took out thirty levees, flooded sixteen islands, and cut off water exports for several months.2

But what the scientists fear most is something called the “Big Gulp.” The name itself sums up the scenario. If the levees break, salt water from San Francisco Bay will come rushing in, proving that nature abhors a vacuum. Lund does a quick back-of-the-envelope calculation: “It would take as little as twelve hours for the salt water to begin intruding into the Delta.”

In another earthquake scenario, scientists simulated a magnitude-6.5 earthquake that takes down twenty islands. This scenario shows a big tongue of salt water creeping in from the bay. Within thirty days, the Delta would be transformed into a saline estuary. The extra salt in the water would wreak havoc on the millions of people and the millions of acres of farmland that depend on Delta waters. Scientists estimate that a catastrophic failure of key levees would cost, in total, somewhere between $8 billion and $15 billion.

Even without catastrophic failure, rising sea levels will bring more salt into the Delta and significantly raise the cost of water treatment; raise the public health risks to the millions of Californians who rely on the Delta as a source of drinking water; and reduce the productivity of farms, which would be irrigated with increasingly salty water. An intrusion of salinity can be delayed for a time by releasing more freshwater into the Delta, as Lund explained, but it cannot be delayed indefinitely.

With regard to an earthquake, there is also the question of when. “If the earthquake happened during the summer when things are dry and water levels are low, it would get salty a whole lot more quickly,” says Hanak. “All these islands are bowls and all of them would be filled with saltwater. If the earthquake happened during winter there would be more freshwater in the Delta to start with, so the Big Gulp would be a lot smaller.” Timing, as they say, is everything.

Unfortunately, global warming is also a matter of timing. Global warming is insidious in that it discreetly fiddles with the timing of the Sierra Nevada snowpack. This snowpack is the true basis of California’s water system. It’s the state’s largest surface reservoir; even though the water is in solid rather than liquid form for several months of the year. Snowmelt currently provides an annual average of 15 million acre-feet of water, slowly released between April and July each year. An acre-foot, as the term implies, is the amount of water needed to cover 1 acre 1 foot deep. More significantly, 1 acre-foot is 325,851 gallons, or about enough water to supply one to two California families for one year or to irrigate from one-eighth to one-third of California farmland, depending on the crop.

Mountain snowpack is like money in the bank. Much of California’s water infrastructure was designed to capture the slow spring runoff and deliver it during the drier summer and fall months. However, warmer temperatures would cause the snow to melt earlier, thereby reducing summer supplies. Using a combination of historical data and climate models, the DWR projects that the Sierra snowpack will experience a 25 to 40 percent reduction from its historic average by 2050, thanks to global warming.

Over the past 150 years, monitored mountain glaciers have been shrinking. And with the earlier melting disrupting the timing, there are now more floods during the winter and worse droughts during the summer. A flood of salt water can of course do enormous damage, but a flood of freshwater isn’t much better. Over the last fifty years, there has been a shift toward less snow and more rain in the Sierra Nevada. Climate change is also expected to result in warmer storms that bring less snowfall at lower elevations; this is more bad news for the snowpack and means, to use the metaphor above, less money in the bank for the state of California. These shifts have increased winter inflows to the Delta. Climate models indicate that this trend will continue, with even larger and more frequent floods in the future.

Whereas you might expect the melting to result in a short-term increase in the amount of water available in the “bank,” the disrupted cycle is actually more likely to cause excess runoff, bringing flooding and an overflow of reservoirs not equipped to contain such large inflows of water. Steve Schneider, a climatologist at Stanford University, puts it this way: “Water managers have this horrible choice. You can leave the reservoirs full and hope you don’t get a heat wave in February or March that melts snowpack early, floods productive farmland, and inundates surrounding communities.”

This is exactly the kind of scenario that scientists expect. A week of unusually high temperatures leads to an exceptionally early snowmelt, which causes a big pulse of meltwater at a time when reservoirs are already full. If that week of heat is combined with a storm that brings heavy rainfall, significant flooding is likely.

Schneider continues with his explanation: “The other option is to play it safe and release water from the reservoirs, bringing the level down. Then you’re praying for rain because you’ve got nothing to fight fires.” Schneider adds, “Either way you’re praying a lot.” This, Schneider says, is why Californians have become deeply involved in climate legislation. “They don’t want to deal with the increased risks of droughts and floods,” he says, “Ideally, they’d be happier with a whole lot less climate change.”

But California has already seen its share of climate change. During the last fifty years, winter and spring temperatures have been warmer, snowpack has been melting one to four weeks earlier, and flowers are blooming one to two weeks earlier. One of the fundamental problems with life on Earth is that natural resources, such as clean water for cities and for growing food, is not evenly distributed in space and time. As a result, we’ve tried to engineer the system to be more evenly distributed. Scientists even out the distribution by looking at past variability and building infrastructure to smooth away the bumps.

But global warming is working against us. So far, California is still betting that a system built using historical hydrological data can protect the future water supply and provide sufficient flood protection. But in the meantime, climate change has already redefined the hydrology of the Delta, making it quite clear that our past experience is not enough to serve as a guide. To think about it any differently would be dreaming.

A rising sea level makes the situation worse. If San Francisco Bay serves as the source of the Big Gulp, then a rise in sea level is the Little Gulp. During the past century, the sea level along California’s coast has risen about 7 inches. It is projected to rise an additional 12 to 55 inches—or possibly even more, if large ice sheets melt—by the end of the century. Without immense investments to raise the Delta’s levees, this rise in sea level will cause many levees to fail, pushing seawater into the Delta. A rising sea level can also increase the rate of saltwater intrusion into coastal aquifers; such intrusions would contaminate freshwater supplies. Even if the levees could be sustained, a higher sea level will increase the salinity of Delta waters. And the higher tide that sweeps in with a rising sea level would pose additional problems.

A higher sea level will make pumping water through the Delta increasingly unattractive and eventually infeasible. Even if the existing levee network could be maintained through unprecedented investments, the worsening water quality resulting from the rise in sea level would steadily reduce the economic value of water exports from within the Delta. The current costs of salinity in the Delta are already significant for agriculture and urban drinking water treatment in the southern Central Valley. More saline exports from the Delta will reduce the viability of agriculture in this region and increase costs of and health risks from drinking water from the Delta. With a continued rise in sea level, the volume of required outflows would continue to increase. Climate models suggest that by mid-century, the increased salinity of Delta waters will impose water treatment costs of about $300 million to $1 billion per year, every year.

Higher salinity will impose a direct water supply cost by requiring higher outflows to keep seawater away from the pumps. Scientists estimate that with a 1-foot rise in sea level, an annual average of at least 475,000 acre-feet of additional Delta outflow would have been required to maintain salinity conditions from 1981 to 2000 at the western edge of the Delta. That works out to about 10 percent of annual export volumes during the period. With an additional 3-foot rise in sea level late in this century, pumping through the Delta may no longer be practical. Steve Schneider says, “And that’s why the Delta is the single most vulnerable place to sea level rise in the entire state. We’ve completely transformed the landscape! And we’ve transformed it in such a way that it has no resiliency. No one was thinking sea level rise when they designed this stuff. It used to be a giant marsh! Now we use it to grow alfalfa for animal feed.”

But California has to play the cards it was dealt. Left to flow naturally through the state’s rivers, most of the precipitation that falls in California would flow out to the Pacific Ocean either directly through the rivers of the north coast or through the San Francisco Bay via the Sacramento and San Joaquin rivers. This would leave the southern part of the state—which contains about two-thirds of the state’s population—with little of California’s available freshwater supplies.

Lund agrees that the Delta is at a tipping point. In 2008, the scientists I mentioned earlier teamed up again, and Lund was the lead author of a report titled Comparing Futures for the Sacramento-San Joaquin Delta.3 The report looked at various options for preventing a catastrophic collapse of the levees. It was meant to offer realistic solutions. It was an opportunity to prevent what might otherwise be inevitable.

“It’s a game of chicken,” Lund says; “and I just hope they can stop playing chicken before the earthquake happens.” Hanak adds, “The current situation in the Delta is bad for the economy and brutal for the fish. Yet folks in the Delta don’t want to see any change. Our evidence suggests that is not possible. They need to be thinking proactively. And they’re going to need help financially.”

If the scientists’ first report was an attempt to envision various future scenarios for the Delta, then their second report presented four possible ways to move the water around. Lund says, “If you want to have a significant amount of long-term water exports from the Delta and you want fish, you need a strategy. You can always screw that strategy up. You can engineer a system with the best intentions and make it worse. But if you do things right, the optimal strategy should at least be better than all the other strategies. Based on our analysis it looked like a peripheral canal was the optimal solution if you want to continue with significant exports.” Hanak says, “It doesn’t mean everyone agrees with us.”

The proposed peripheral canal (a canal that goes around the periphery of the Delta) is fairly straightforward, and it isn’t new. The first such proposal was defeated in a state referendum in 1982; Northern Californians turned out in force to vote against it. As a result, it remains controversial today. The scientists are now offering a proposal that improves on the original concept but conservation groups are still worried that if a peripheral canal is built, it will allow for even more unsustainable levels of water exports to the south. They might be right. As Lund says, you can screw up anything.

But if we don’t screw it up, the canal would protect water exports in the event of a levee failure and would also help reduce the extent to which water flow is altered by the current configuration of the pumps. Pumping water directly out of the Delta clearly hurts the environment. Water diversion pumps in the southern Delta are so powerful that they actually make the Delta’s maze-like channels flow backward. Hanak explains it this way: “You’re not sucking water through the Delta to the pumps. The peripheral canal decouples the management of water for humans with the water for the Delta ecosystem. You bring the clean water directly to the pumps and you don’t have to keep the Delta fresh. It’ll get saltier in the fall. We pump all year round right now. You’re also not sucking the fish down. We’ve been operating this system and pumping so much the rivers go backward. You’re not as vulnerable to a catastrophic levee failure. You just have to repair the canal, not the entire levee system.”

The scientists see the canal as an essential way to separate the state’s water demand from a Delta environment under grave stress. Sixteen Delta fish species are being pushed toward extinction, in part, by this demand.

“If you’re just worried about fish,” Hanak explains, “you want absolutely no water exports. But the engineering question is: how much water can you take out of the system and not hurt the fish? If you’re optimizing over both human needs and ecosystem needs, you’ll see reductions in uses for things like low-margin agriculture. It will force us to cut back on lands that are least productive. It’s hard to do. And that’s why this is one of those things that has been off the table for a long time. The Bay Area actually depends more on the Delta than Southern California does. Most of the growth in the Bay Area has relied on water from the Delta. If Bay Area folks understood the implications, then I don’t think they would object.”

The peripheral canal would deliver water from the Sacramento River along the Delta’s eastern edge and then down to the pumps in the south, in effect circumventing the Delta itself. That’s why it is called peripheral. It requires building an earthen canal wider than two football fields and more than 40 miles long. The canal would give the Bay Area and Southern California a direct line to tap into the Sacramento River. The channel would divert some of the river’s flow around the fragile Delta and on to existing pumps in the southern part of the Delta. From there, the river would continue to serve Los Angeles, San Diego, farms in the San Joaquin Valley, and much of the Bay Area.

Originally, the peripheral canal was seen only as a water conveyance. Now, many scientists also view it as a restoration tool and a hedge against disaster. But residents along the eastern edge of the Delta are concerned about the effects of a 40-mile canal with a footprint 1,000 feet wide. For this reason, scientists say that any consideration of a canal must first begin with a commitment to water conservation and efficiency efforts on a scale not yet attempted in California. Hanak says the price of the peripheral canal would be somewhere between $5 billion and $10 billion.

“That’s not such a big problem,” she says. “Water users can cover that. The current system is so unreliable and risky. The bigger question is who pays for improvements in fish habitat and for the mitigation for farmers who rely upon the Delta to make their living.”

Lund adds, “It’s about adaptive management. We don’t really have any other choice when you begin to factor in the impacts of climate change, like sea level rise, and how these new forces will be pushing on the system. If we go ahead and build the peripheral canal, we’ve essentially constructed a whole new Delta. We’re not going to know exactly how to operate it.”

Adaptive management is an admission that pinning a situation down will never work, but it requires a willingness to make changes and to be flexible. “It’s real water and it’s real money to someone,” says Lund. “It’s very hard to do adaptive management because every experiment is real water and real money. But we need to do this.”

That said, Lund still thinks the more likely possibility is that, as in the case of Hurricane Katrina, the decision regarding what to do will be made for us, something Lund calls “failing into a solution.”

According to Lund, “The physics is not going to wait for the policy to be put in place. If you have the big earthquake, the event forces you into making the quick policy decision. And that quick policy decision could be a complete disaster. That’s what I call failing into a solution.” When I asked Lund if he thought it was likely that a good policy decision could be made in advance of the worst-case scenario, he wasn’t necessarily optimistic. “It’s incredibly difficult to reach a consensus. It asks too many people to give up too much.”

But if an adaptive style of management were to go into effect, it could also deal with other big problems—the kind of problems that come with living in a place subject to extreme weather and extreme climate. For example, El Niño—the periodic warming of the Pacific Ocean—routinely inflicts millions of dollars’ worth of damage on California. Losses caused by storms and floods during the 1997-1998 event alone were over $1 billion. Adaptive management would help reduce the state’s vulnerability to El Niño events. Schneider says climate change is another problem that could be addressed. “The two big problems you need to keep in mind when you think about climate change in California,” he says, “are wildfires and pollution.”

California has the worst air quality in the United States. More than 90 percent of the population is in areas that violate the state’s air quality standard for either ground-level ozone or airborne particulate matter. These two types of pollutants can cause or exacerbate a wide range of health problems, including asthma and heart attacks. They have also been shown to decrease lung function in children. Combined, ozone and particulate matter contribute to 8,800 deaths and $71 billion in health care costs every year. The connection with global warming is nothing more than simple chemistry. Higher temperatures increase the formation of ground-level ozone and particulate matter. Ambient ozone also reduces crop yields and harms the ecosystem. If global background ozone levels increase as projected in several future climate scenarios, it may become impossible to meet local air quality standards. Air pollution events will become more frequent, longer-lasting, and more intense as temperature increases. For example, scientists at the California Climate Change Center forecast that the scenario based on moderate temperature increase almost doubles the number of days with weather conducive to ozone formation in the San Joaquin Valley, relative to today’s conditions.

And then there are wildfires. Warmer temperatures, drier conditions, and increased winds could mean hotter wildfires that are harder to control. Aside from their destructive potential, wildfires also increase levels of fine particulate matter. Therefore, air quality could be further compromised by increases in wildfires, which emit fine particulate matter that can travel long distances, depending on wind conditions. The most recent analysis suggests that if greenhouse gas emissions are not significantly reduced, large wildfires could become up to 55 percent more frequent toward the end of the century. The California Regional Assessment notes an increase in the number and extent of areas burned by wildfires in recent years; and modeling the results under changing climate conditions suggests that fires may be hotter, move faster, and be more difficult to contain in the future.

When I ask Hanak what the Central Valley might look like by 2050 if we do nothing, she says, “The Delta water system will not be viable. You’ll see a lot of open water, and the folks who depend on that water won’t have access to it. We’re likely to lose 1 million acres of San Joaquin farmland. It wouldn’t be a devastation to the state economy, but it would certainly hurt that region, one of the country’s most productive farming areas.” In 2009 the California Climate Change Center released a report that builds on this picture. According to the report, water shortages across California are more likely in the future as snowmelt decreases, the climate warms, and the population grows. California’s population is expected to grow from 35 million today to 55 million by 2050.

Climate models suggest that by the end of the century, late spring stream flow could decrease by one-third. Agricultural areas could be hard hit, with California’s farmers losing as much as 25 percent of the water supply they need. Climate models indicate that by 2050 the average annual temperature in California will rise between 1°F and 2.3°F, depending on the level of global greenhouse gas emissions. And by the end of the century, if emissions proceed at a medium to high rate, temperatures in California are expected to rise somewhere between 4.7°F and 10.5°F. In a more optimistic scenario, with lower greenhouse gas emissions, temperatures still go up between 3°F and 5.6°F by 2100. If temperatures rise to the higher warming range, there could be as many as 100 more days per year with temperatures above 90°F in Los Angeles and above 95°F in Sacramento by 2100.4

In 2010, the peripheral canal will be under the spotlight as the proposal reaches the governor and the legislature. There will be lots to wrangle over, including whether and how to build it, as well as how the state will buy up land for 100,000 acres of environmental restoration in the Delta. A committee of government agencies is working on a related habitat conservation plan for the Delta, also due in 2010, which is expected to include a canal. The state Department of Water Resources is drafting an environmental impact report on canal options, also due for completion in 2010. Lund says, “You never know what will come out of the sausage machine that is politics.” But what seems clear is that a classic Hollywood ending is unlikely.

Hanak and Lund will tell you that in order for the Delta to survive, it will need a substantial overhaul. They can offer what they see as an optimal solution, but they can’t offer a perfect solution. The optimal solution means that some fish will still die and some farmers will lose their livelihood. It is not—to repeat—a Hollywood ending. The problem with engineering is that it provides a methodology for calculating your losses ahead of time. That means you have to take responsibility and accept those losses. Lund is not sure rational solutions are the inevitable choice, because people would rather simply hope for a happy ending. “The most likely outcome is we will not be able to decide in time. And our reports will be used as a hind-cast instead of a forecast. Our studies will serve as a nice example of what could have been done. And we will forever be known as the Katrina scientists of the Sacramento-San Joaquin Delta.”

The Central Valley, California: The Forty-Year Forecast—Drought, Water Resources, and Agriculture Problems


Forecast April 2017

By 2017, the future began to reveal itself to the residents of California. Temperatures continued creeping up, winters were becoming increasingly tepid, and spring came earlier and earlier. Summer seemed to last forever, whereas the Sierra snowpack was gone by June. None of this came as much of a surprise. It had always been fairly easy for the climate models to forecast temperature. Mostly, we were just relieved that it wasn’t worse. At least the seasons were still pretty much the seasons, even if they were all tracking warmer than they should be. Those all-important winter storms that blew in from the North Pacific Ocean bringing rain and the occasional snowfall, part of the classic so-called Mediterranean seasonal precipitation pattern, were still around. We figured that as long as the timing of the rains remained about the same, California could focus on dealing with the heat.

It was in 2017 that a storm gathering in the Pacific would redefine how we looked at winter. It would also redefine how we looked at the ocean-atmosphere phenomenon called El Niño, a periodic warming of the equatorial Pacific Ocean. El Niño was now further juiced by all the extra heat in the atmosphere, and the winter storms it brought were expected to knock some of California’s rainfall records out of the ballpark.

For the most part, El Niño events typically lasted about one year. But coral records from Palmyra Island in the tropical Pacific Ocean suggested that there were periods in the past when both the amplitude and the frequency of El Niño events changed abruptly.5 Whatever the cause, the present El Niño seemed to be different. As the climate models struggled to describe how global warming might influence El Niño events in the future,6 we watched as it changed right before our eyes.

The warming of sea surface temperatures in the equatorial Pacific was evident by early April 2017. And in early June, the NOAA Climate Prediction Center issued an El Niño Advisory stating that ocean temperatures in the central and eastern Pacific Ocean were the warmest since August 1997. Until now, the 1997-1998 El Niño had been one of the strongest in recorded history. It was lucky for California that we had learned from past mistakes. Following the large El Niño of 1982-1983, an event that went largely undetected until it kicked California in the teeth, federal money was used to make improvements to the observational network that fed into the climate models. With the installation of the TAO/TRITON array of moored buoys, scientists finally had more comprehensive data regarding the condition of the tropical Pacific Ocean. The data collected by means of this improved observing system supplied the climate models with very high-resolution snapshots of ongoing ocean conditions. The models, in turn, predicted that a strong El Niño was now growing in the Pacific and that it would continue to grow through early 2018 and perhaps even longer—with emphasis on the word longer.

By late spring 2017, scientists at NOAA issued a climate forecast for the approaching winter months, highlighting El Niño’s probable impact on temperature and precipitation patterns in the United States. Mother Nature’s forecasts, often more subtle, were not far behind. Luckily, there were plenty of old-timers, knowledgeable about wild creatures and the local environment, who were still capable of reading these more subtle messages with great skill. Phone calls came pouring in to the Marine Mammal Center in Sausalito about sightings of stranded sea lions. The sea lions, unable to find enough anchovies or herring, were malnourished. It was likely that the warming ocean temperatures associated with the growing El Niño were driving the fish away.

A lack of upwelling of cold water along California’s coast was the key to many of the strange sightings. Wind-driven upwelling of cold, nutrient-rich deep water acts as a feeding trough. But El Niño turns down those winds, and that downturn reduces the upwelling. Reduced upwelling prevents nutrient input to surface waters, lowers the amount of plankton—tiny marine plants and animals—and messes with nearly everything that relies on the ocean for sustenance. Biologists studying salmon in the waters off San Francisco reported finding razor-thin sardines and anchovies, underweight for their size and probably undernourished. A brown pelican was spotted in a suburb of Phoenix, probably propelled by El Niño winds from the California coast all the way to Arizona. An official from the Maricopa Audubon Society explained that many starving birds had just given up and let the wind carry them.

According to NOAA’s El Niño Watch, tropical El Niño conditions would continue to gain strength through January along the U.S. west coast, with sea surface temperature (SST) departures similar to those observed in December. The SSTs were 5°F to 6°F above normal off the northern California coast, more than 6°F above normal off the coast of San Francisco and Southern California, and 4°F to 5°F above normal off the coast of the Pacific Northwest.

By February the worst of the winter brought heavy rains, flooding, and mudslides in northern California, and there were flood warnings for the Russian and Napa rivers. Interstates were shut. Heavy surf, rising to 50 feet, eroded beaches. As much as 14 inches of rain fell in Santa Barbara. Hurricane-force winds of up to 95 miles per hour caused devastation. Residents of Sacramento stockpiled sandbags and cleaned out channels. And the 2 million people of the Central Valley who were counting on the levees for flood protection heaved a sigh of relief. The levees, for the most part, had survived the storm intact. But the overall frailty of the levee system was in plain sight, and the storm revived stalled discussions about the need for a peripheral canal. It was clear that something had to be done, and it was hoped that this El Niño might serve as the impetus.

After the first El Niño dissipated, climate models forecast one more round. In other words, the El Niño of 2017-2018 was technically the first of a pair. Surfers in Newport Beach had a field day. But while they were riding the best winter waves of the century, California itself was riding headlong into an economic meltdown. This time it was caused by a flood of water as opposed to a flood of bad mortgages. The state, still suffering from the bursting of the real estate bubble in 2009, was already strapped for cash and ill-equipped to make any significant infrastructure upgrades. There was talk of trying to float a $10 billion bond for the peripheral canal. But in the end, no one had the cash to support it.

There was one small gift amid all the wreckage. The El Niño rains generated a blooming of spring flowers across Death Valley. The winter storms that brought mudslides and death to Southern California dropped more than 10 inches of rain on this thirsty desert—five times more than usual—persuading the hearty wildflower seeds to blossom year after year. Death Valley hadn’t seen such an array of flowers since the spring of 2005, almost fifteen years earlier. In March and April 2017, tourists came from around the world to see the landscape repainted in the rich blue of the desert lupine, the royal purple of the chia flower growing in clumps along the side of the road, the magnificent golden yellow of the California poppy and the desert dandelion, highlighted by the soft white petals of the tufted evening primrose scattered across the hillsides.

August 2027

By 2027, the dream that was California had begun to unravel. Temperatures across the Golden State, which had been rising since the 1950s, started to spike. August 2027 saw new record high temperatures being set almost every day. As one local meteorologist put it, “The good news is that the number of official heat waves in Sacramento this year is finally down, the bad news is that the heat wave that started in July is still going strong.” Sacramento, along with much of the U.S. Southwest, was trapped in one long heat wave.

The intensity of this heat wave was crushing, and the duration of abnormally high maximum and minimum temperatures was reaching into every sector of California’s economy. An all-time record for statewide energy consumption was set, and hundreds of heat-related deaths were reported. Meteorologists watched in awe as the semipermanent four-corners high-pressure system expanded to the west and north. Associated with this expanded high-pressure system was an unseasonably warm air mass settling over the region through the duration of the event, with an influx of monsoonal moisture from the Gulf of California and the Baja region. Typical mid-level winds from the southwest shifted to the southeast. This allowed for maximum transport of moisture over southern and central California, and served to lift minimum overnight temperatures higher. It also brought excessively humid conditions during the daytime hours—a situation not typically associated with California. In other words, California felt like Louisiana.

The heat wave proved devastating to the state’s $3.2 billion winemaking industry. California, still the nation’s largest wine producer and the fourth-largest wine producer worldwide, with its high-quality wines produced throughout the Napa and Sonoma valleys and along the northern and central coasts, had, in a sense, come under siege. High temperatures during the growing season caused grapes to ripen prematurely and reduced their quality. Specifically, an increase in the overall number of temperature extremes above 86°F during the growing season had shut down photosynthesis. Cooler spots, such as Mendocino and Monterey counties, were still hanging in. But the grape-growing regions of the Central Valley, with its already marginal conditions, were hit hard. California’s losses due to heat were estimated at 30 percent and close to $1 billion.

It was a summer that seemed like science fiction and apparently wasn’t set on the planet Earth. Mudslides became a big problem in areas deforested by wildfires, and these slides were almost impossible to escape. Airports were virtually forced to shut down as plane after plane was grounded, week after week, by decreased visibility from the wildfires. Air quality became unbearable. The entire state violated air quality standards for ground-level ozone (smog) and small particles. Air pollution in Los Angeles and the San Joaquin Valley was especially bad. The cost of managing an unruly climate had become crippling.

The models were right: over the past two decades, California’s average temperature had risen somewhat more than 2°F. The temperature increase was further proof that a high-emissions scenario was happening. This meant that by mid-century, the serious changes would to start to kick in. And if nothing was done to ramp down emissions, by the end of the century, climate models projected that statewide average temperatures would rise more than 10°F. We couldn’t even manage 2°F.

October 2040

By 2040, the seasons had become almost unrecognizable. The heat hung on as summer extended into a long, mind-numbingly brutal test of patience. Rainfall had become erratic, and a cool patch of tropical Pacific Ocean temperatures suggested that we were locked in something like a prolonged but sketchy La Niña event. For the U.S. Southwest, La Niña is synonymous with drought. Water was on everyone’s mind.

Ironically, the original pact that governs water supply in the West was negotiated in 1922, during one of the wettest periods of the past 1,200 years. Paleoclimatologists, analyzing tree ring records across the Southwest, said it was only a matter of time before the western United States reverted to its old ways and the Colorado River became drier again. We knew that global warming would push the system back into drought harder and faster.

Climate change was indeed a game changer, especially for utilities and water managers who were trying to make sure everyone had a fair share. The pact of 1922 that allocated Colorado River water to California, Nevada, Arizona, Utah, Colorado, New Mexico, and Wyoming had come about in a very different world and did not fit readily into this new one. There was still plenty of argument about whether the new reality was in fact new or just an old reality come back to haunt us. But in any case, the reality was that it wasn’t raining.

As the seasons became unfamiliar, so did the landscape. Its color and texture had begun to shift before our eyes. To start, high-elevation forests in California were receding. They just couldn’t take the heat. Almost half were gone, replaced by grasslands. The desert, once lush with wildflowers, was being slowly overtaken by alien species such as red brome and buffle grasses—plant species native to Africa and the Mediterranean and able to do well in high temperatures. Not only did these noxious weeds outcompete some native species in the Sonoran Desert; they also fueled hot, cactus-killing fires. The magnificent saguaro cactus (Carnegiea gigantea)—the state flower of Arizona—and the Joshua tree (Yucca brevifolia) had become hard to find.7 In fact, the majority of California’s native species, numbering well over 3,000, were fading. It seemed as if everything was heading for the hills—but the hills were on fire.

One of the first lessons regarding climate change is that the conditions of the past can’t predict the future. The Hoover Dam, completed in 1936 and once a proud symbol of American engineering power and vision, became a sorry reminder of our collective inability to change with the times, let alone stay one step ahead. Straddling the border between Nevada and Arizona, Hoover Dam was built to tame the flow of the magnificently wild Colorado River, which stretched over 1,450 miles from Colorado’s Rocky Mountains to the Gulf of California. The Colorado River had supported the growth of cities such as Las Vegas and Phoenix, providing about 30 million people with water for drinking and irrigation. By the year 2040, Hoover Dam was empty, and a sort of bathtub ring—a thick white band of mineral deposits—marked the walls of Black Canyon. That ring showed where the waterline used to be—before the rain stopped but while the people kept pouring in.

Before the last drops were released a few months ago—to Las Vegas, Los Angeles, San Diego, Phoenix, Mexico, and some other places—our strategy had become hope and prayer. We hoped and prayed that life would just go back to the way it used to be, when there was still rain and we didn’t have to think about water all the time. Casinos like the Bellagio and Mirage, with their beautiful fountains, lagoons, and waterfalls, reinforced our hope and made it easy for us to think that everything would be fine. My favorite was Planet Hollywood, where it rained every hour on the hour, day after day. The daily rain show became one of the most popular attractions—it almost seemed to prove that Sin City could not possibly be in the midst of a water crisis.

But Lake Mead and Lake Powell were always the biggest poker tables in Nevada. Back in 2009, water resource managers at the Southern Nevada Water Authority were asking all the right questions about the cards they were holding. Was the drought one of the traditional droughts that the Colorado River had experienced in the past, or was it something very different? In just two weeks in April 2009, managers watched as Lake Powell lost the equivalent of 14 feet of snowpack. And by the summer of 2009, the reservoir’s water level fell to its lowest point since 1965—back when Lake Powell was new and officials first diverted water from the Colorado River into it. By the end of August 2009, Lake Mead’s elevation teetered at just 1,092 feet above sea level. Water resource experts knew they were betting on the future of the West. A mere 17 feet stood between hope and despair. By law, once the level dropped below 1,075 feet, the Southern Nevada Water Authority was required to find alternative sources of water. The future of water in the West, the future of great bottles of cabernet and zinfandel, the future of beautiful apricots and almonds and avocados, the future of life itself, depended on that 17 feet.

The models had been predicting that climate change could reduce the runoff that feeds the Colorado River between 5 and 25 percent by the middle of the century.8 But there was a big difference between reduced runoff and empty reservoirs. That difference was a matter of managing the double whammy of climate change and population growth. One problem was that even under the most extensive drying scenario—a drop in runoff of 20 percent—water supplies wouldn’t be affected immediately, because Lake Mead and Lake Powell, which could store up to 50 million acre-feet of water, provided a significant cushion. In fact, the total storage capacity of all the reservoirs on the Colorado exceeded 60 million acre-feet, almost four times the average annual flow on the river itself. As a result, scientists calculated the risk of complete reservoir depletion as low through 2026, making it easy to postpone action. But after that, all bets were off, and the risk soared. Good management could reduce the risk, but a policy of business as usual meant that under a worst-case climate scenario, by mid-century there was one chance in two of empty reservoirs in any given year. The scientists cautioned that if the water managers took aggressive steps to reduce downstream releases during periods of drought, it would still be possible to cut their losses by as much as one-third. But they warned that if the managers did nothing, as the West continued to warm, a drier Colorado River system could have a risk as high as one chance in two of completely depleting all of its reservoir storage by 2050. At the time, it was anyone’s guess when or if Lake Mead would reach that point.

Looking back, the water resource managers did the best they could, considering that the country was in the midst of a recession. The national economic downturn reduced the utility’s revenues just as they came to see the risk of climate change and wanted to take steps toward new infrastructure investments. Even so, they managed to allocate $800 million and embarked on a large-scale construction project to build a new intake pipe to pull water from Lake Mead. This project, known as the third straw, was a way to ensure that the utility could siphon water if the lake level dipped below 1,000 feet, the point at which the two existing intakes became useless. It was an excruciatingly difficult project, but they got it done. And it bought us extra time. They also sought permission to build a controversial $3.5 billion pipeline to transport groundwater from ranches in rural eastern Nevada. But the pipeline plan drew so much ire from ranchers and environmental groups that it never made its way out of court.

July 2050

Despite the fact that scientists had run countless simulations of an earthquake in California’s Central Valley, the first twenty-four hours of the real thing were terrifying. It was a magnitude-6.5 earthquake, and it took down twenty islands in the San Joaquin Delta. As the levees collapsed, salt water from San Francisco Bay rushed in. The islands, now acting like bowls, filled up with salt water. It took a little more than thirteen hours for the salt water in San Francisco Bay to begin filling up the Delta. Unluckily, the earthquake happened during the summer, when the ground was dry and water levels were low. Just as predicted in an earlier scenario, within thirty days the Delta became a saline estuary; salt water ravaged millions of acres of farmland that had come to depend on freshwater from the Delta; and a catastrophic failure of important levees cost more than $16 billion. The president declared the Central Valley a federal disaster area. Federal and local lawmakers vowed to rebuild, and plans for a peripheral canal were finally put on the fast track.