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19th May 2022

In California, millions of residents and thousands of farmers depend on the Bay-Delta for fresh water—but they can’t agree on how to protect it.

By David Owen
May 11, 2022

The Sacramento is California’s largest river. It arises near the lower slopes of Mt. Shasta, in the northernmost part of the state, and runs some four hundred miles south, draining the upper corridor of the Central Valley, bending through downtown Sacramento, and, eventually, reaching the Pacific Ocean, by way of the San Francisco Bay and the Golden Gate Bridge. Erik Vink, the executive director of the Delta Protection Commission, a state conservation agency, described the Sacramento to me as “California’s first superhighway.” By the eighteen-fifties, daily steamboats ferried passengers between San Francisco and Sacramento in as little as six hours. Travellers now mostly use I-80 to cover the same ninety miles, and oceangoing ships bound for the Port of West Sacramento finish their trip in a deepwater canal built sixty years ago by the Army Corps of Engineers. But the Sacramento is still important: it and its tributaries make up the state’s single largest source of fresh surface water. Most precipitation in California falls in the north, while the biggest users, including all the major metropolitan areas and the immense farms of the San Joaquin Valley, are farther south. Devising ways to move water from wet places to dry places has been the labor of generations. During the past century and a half, miners, farmers, politicians, engineers, conservationists, and schemers of all kinds have worked—together and against one another—to create one of the most complex water-shifting systems in the world.

In mid-February, I ate lunch at Bethany Reservoir State Recreation Area, a ninety-minute drive south of Sacramento, with Jay Lund, who is a co-director of the Center for Watershed Sciences at the University of California, Davis, and Peter Moyle, an emeritus professor at the same university. Lund is in his sixties, and Moyle is almost eighty. Spring was well under way—on our drive to Bethany, we’d passed hundreds of acres of blossoming almond trees with neat stacks of beehives spaced at intervals along the rows, for pollination—but the weather was still cool enough for jackets. Before we ate our sandwiches, Lund unrolled a laminated sheet on top of our picnic table. The sheet was three feet wide and so long that one end drooped almost to the ground. Its surface was covered with lines, arrows, symbols, and small blocks of text—a maze-like network that could have passed for the wiring diagram of a nuclear power plant. In fact, Lund explained, it was a schematic of the state’s water infrastructure, the inflows and outflows, both natural and man-made.

Near the middle of the picnic table, maybe three feet from the edge that represented the Oregon border, was a small label indicating “The Delta.” It marked what Lund described as the most important element of California’s plumbing: an expanse of some seven hundred thousand acres, east of the Bay Area, formed by the confluence of several rivers, the largest of which are the Sacramento and the San Joaquin. For tens of millions of Californians, the Delta—which is also known as the Sacramento-San Joaquin Delta, the Bay-Delta, and the California Delta—serves as a hydrological hub. “The Delta ties everything together,” Lund said. All the fresh water that farms and cities in the south import from the north comes from it. Not far from our picnic table, large pumping stations were sending Delta water to other parts of the state.

In 2014, while I was researching an article and a book about the Colorado River, I interviewed Pat Mulroy, who had recently retired as the general manager of the Southern Nevada Water Authority and had just become a fellow at the University of Nevada’s law school. She surprised me by saying that the condition of the Delta—which lies several hundred miles outside the Colorado’s watershed and which I’d only just heard of—posed as grave a threat to the Colorado’s long-term stability as the shockingly low water levels I’d seen in its two largest reservoirs, Lake Powell and Lake Mead. Seven Western states and Mexico divert water from the Colorado, which for decades has been depleted by drought and unsustainable use. As Mulroy and I spoke, California was already being forced to reduce its withdrawals. The Delta is crucial because, if it ever failed as a hub, the resulting water crisis in California would increase existing tensions with the Colorado’s other parched dependents. “One good earthquake would do it,” Mulroy said.

News stories about the Western drought often focus on the Colorado and its reservoirs. The drops in their water levels are easy to see. A little over twenty years ago, Lake Mead was full, but since then, its volume has shrunk by two-thirds. As the water has disappeared, it has left a broad band of light-colored mineral deposits, known as the “bathtub ring,” on the surrounding canyon walls. The Delta’s problems are as dire, but they receive far less public attention. (No bathtub ring.) Up close, the Delta doesn’t look like much: a huge expanse of flat agricultural land, with relatively few signs of human habitation. On Google Earth, it resembles a triangular green jigsaw puzzle. The principal puzzle pieces are five or six dozen irregularly shaped islands, which are separated from one another by seven hundred miles of sloughs and meandering waterways. The islands are actually what the Dutch called polders; they’re landforms that farmers created, beginning in the nineteenth century, by draining natural wetlands. Most of the islands cover thousands of acres. All are surrounded by dikes, which are known locally as levees; their purpose is to keep water from flooding back in. The cultivated fields inside the levees have gradually subsided, and in some places are now twenty-five feet below sea level. One consequence is that Delta farmers, in addition to siphoning irrigation water from the channels that surround their islands, have to pump water out—a chore familiar to anyone who has used a sump pump to keep a basement dry.

The main threat to the Delta is saltwater intrusion. If an earthquake caused a major levee failure, the sunken islands would flood, drawing salt water from the Pacific into waterways that are now kept fresh by the pressure of inflows from the Sacramento. “Instantly, your fresh water turns to sea water,” Mulroy said—and, at that moment, a resource that millions of Californians depend on for drinking and irrigation would be unusable. A month before my interview with Mulroy, I had met with Bradley Udall, who had just joined Colorado State University as a senior water-and-climate-research scientist. During our conversation, he described the Delta to me as “the biggest potential water disaster in the United States.” That was eight years ago. In the meantime, the drought has continued, making all the problems worse.

When the Spanish first sailed into San Francisco Bay, in the late seventeen-hundreds, the water was so clear that a sailor could look over the side of a ship and see shoals of fish swimming at the bottom. The noise made by salmon at night, as they migrated up nearby streams, was loud enough to keep people awake, and there were so many ducks, geese, pelicans, cranes, and other birds that when they took flight they darkened the sky. Elk, deer, antelope, beavers, and grizzly bears were abundant. The hills surrounding the bay were covered by ancient forests. The Central Valley—California’s most productive agricultural region, which runs much of the length of the state, between the Sierra Nevada and the Coast Ranges—was a lush seasonal wetland.

All of that began to change in 1848, when a carpenter who was helping to build a sawmill for a Swiss immigrant named John Sutter noticed something glittering in the mill’s tailrace: the beginning of the California gold rush. An emergent mining technique involved shovelling gravel and dirt into an open-ended trough, called a sluice box, then running water over it. Gold is so dense that it settles into riffles in the bottoms of the sluice boxes as the lighter material is washed away. Miners soon realized that they could get rich quicker if they built bigger troughs and increased the volume and speed of the water. They diverted mountain streams into wooden flumes and broad pipes, then used canvas hoses with iron nozzles to aim the resulting water jets at entire hillsides. That technique was called hydraulic mining. The water jets were so powerful that, according to contemporary reports, they could kill people standing two hundred feet away. Samuel Bowles, an influential New England newspaperman (who was also a friend of Emily Dickinson’s and an early reader of her poems), visited the Sierra foothills in the eighteen-sixties. “Tornado, flood, earthquake and volcano combined could hardly make greater havoc, spread wider ruin and wreck, than are to be seen everywhere in the path of the larger gold-washing operations,” he wrote. Hundreds of millions of tons of sediment were pushed downstream, burying some farmland as far away as the Delta.

As significant as the gold rush, in terms of the physical and cultural transformation of California, was the passage, by Congress, of the Swamp Land Act of 1850. One of its purposes was to facilitate the conversion of Florida’s Everglades into arable land, but its provisions also applied to several other states, California among them. As frustrated forty-niners gave up on gold, they often turned to agriculture. Speculators acquired large wetland tracts, then built levees, drained marshes, and cut or burned existing vegetation. They grew potatoes, beans, corn, asparagus, cabbages, and other row crops, and riverboats carried their produce to market. They cut down so many trees, partly to provide fuel for the riverboats, that the only real surviving remnant of the region’s ancient forests is the name of the city at the eastern end of the Bay Bridge: Oakland. The enterprise was made possible by the immigration of laborers from China and, beginning in the late nineteenth century, by the use of steam-powered dredges. The modern Delta was born then.

Two days before our picnic at Bethany Reservoir, Jay Lund and I spent most of the afternoon on waterways near the Delta’s southwestern tip, in a boat owned by William Fleenor, an engineer and emeritus senior researcher at the Center for Watershed Sciences. Fleenor’s boat is fifty feet long and has a catamaran hull. We set out from the Pittsburg Marina, near the place where the Sacramento and the San Joaquin flow together. (The San Joaquin arises in mountains near Yosemite National Park, runs northward in the Central Valley, and enters the Delta from the south.) We headed up the mainstem of the Sacramento, and were soon passed by the Atlantis Discovery, a six-hundred-and-ten-foot-long bulk carrier, which was going the other way. I learned later, from a ship-tracking Web site, that it had left South Korea a month before, had unloaded cargo in West Sacramento, and was now heading back toward the Golden Gate. We gave it a wide berth.

Continued in Part 2