Requiem for a River

(Page 2 of 5)

As the region heats up, and as more precipitation falls as rain and less as snow, it might seem that rainfall would simply make up the deficit. Even leaving aside the likelihood that precipitation of all kinds will decrease, studies of groundwater chemistry show that in many parts of the West, up to 90 percent of groundwater comes from melting snow. During the spring thaw, a few months' worth of water flows down the mountains within weeks, and the concentrated rush penetrates dry terrain more deeply than intermittent rains can.

"It's really interesting to ask what it means for the biology up here," Baron says. "Are we likely to see a change in when plants flower or put on leaves? If you get a big pulse of snowmelt earlier than before, does that mean these ecosystems dry out earlier in the year? And what would that mean for tundra, for meadows, for forest? Do they go into drought stress earlier, and is it more severe, and what will that do?"

The day after my hike with Baron, I drive north along the western slopes of the Rockies through a blizzard that clears as I descend into Kawuneeche Valley, the location of Grand Lake, the largest natural body of water in Colorado and part of the river's headwaters. The stream feeding into the lake here is not yet out of the mountains, but already it is being diverted. Grand Lake is the first of many locations where water that would otherwise run unimpeded to the Gulf of California is sluiced away toward cities and farms.

The diversion project, though enormous, is mostly invisible. On the southeast shore of Grand Lake, concealed beneath its surface, is the entrance to a 13-mile-long tunnel bored in the early 1940s clear through the Rocky Mountains. The nine-foot-wide Alva B. Adams Tunnel can bring up to 550 cubic feet of water every second across the Continental Divide to the cities and farms on Colorado's dry eastern plains. Perversely, while 80 percent of Colorado's precipitation falls on the west slope of the Rockies, 80 percent of the state's population lives east of the mountains. The tunnel spreads the river's bounty all the way to the northeasternmost corner of the state.

Just north of Grand Lake, with a few feet of snow on the ground and winter still stubbornly holding out in the mountains, one could almost forget the drought and doubt the existence of global warming, were it not for the dead trees. Tens of thousands of lodgepole pines cover these slopes. Many of them have been standing for well over a century; now a large number are dying, victims of a decade-long mountain pine beetle infestation. The beetles killed close to five million lodgepole pines in Colorado in 2006, nearly a fivefold increase from the previous year. About 43 percent of the state's lodgepoles have been infected. Trees at this elevation had been largely immune from the assault, but warmer temperatures have increased the beetles' range. Rust-colored and dead, the forests are a somber warning sign of climate change.

After parking my car along the roadside, I trudge through deep snow a few hundred yards into the forest. Beyond a stand of trees the Colorado glints into view, a shadowy umber band chiseled on a field of white. In the distance, clouds of blowing snow flare like shaggy manes from the peaks of the Never Summer range. The river in this snow-covered meadow is really still a mountain brook, barely six feet across, the water only ankle deep. Delicate sheets of ice jut from the banks, but the swift current prevents the river from ever completely freezing over.

The Colorado got its name from the color it acquires from sediments downstream, but here, some 70 miles northwest of Denver, its waters are clear. Although some other American rivers are longer, none is more crucial to its watershed than the Colorado. The lowlands' contributions to the river are relatively modest: about half of the water that reaches Hoover Dam comes from just 15 percent of the watershed's land area here in the mountains. But whatever the water's provenance, not a drop of it will ever reach the sea. Seven states, two nations, 14 dams, farms, cities, and evaporation will claim it all.

Page, Arizona
[Elevation 4,118 feet]

You know you're living in a nation that's congenitally warped by easy abundance when, on a 90-degree april afternoon, you see a large boat being hauled along a highway through the desert. On the road to Page, Arizona, assorted vessels on trailers are not an uncommon sight, and the welcome sign at the town limits sports a sailboat painted on a blue background.

Fifty-one years ago Page didn't exist. Nor did Lake Powell, the 186-mile-long reservoir that stores about two years' worth of the Colorado River's flow behind the 710-foot-tall concrete wall of Glen Canyon Dam. Page, which sits atop a mesa 600 feet above the lake, was originally a camp for the workers who began building the dam in 1957. Now it's a resort town with three golf courses and nearby marinas.

The dam was controversial from the start. The reservoir it created submerged some of the most spectacular red rock canyons in Utah, with formations rivaling those of the Grand Canyon. The rising waters drowned plants and wildlife, inundated towns and archaeological sites, and turned the canyon's solemn ancient buttes into archipelagoes.

On my second day in Page, I succumb to the lure of the immense flooded canyon and join 69 other tourists for a daylong excursion on Lake Powell. The drought's toll is visible everywhere. A fat white stripe of calcium carbonate deposits left by evaporation stretches 100 feet or more above the waterline, staining the red sandstone canyon walls. Once underway, our boat hits 20 knots and kicks up a good wake, passing dozens of multimillion-dollar houseboats. One has four Jet Skis lashed to its stern deck; another has a hot tub.

Lake Powell, with its many inlets, has a coastline longer than California's, and over the course of the day, Melvin Howard, our captain, pilots us into side canyons so narrow that passengers on either side of the boat can touch the smooth sandstone walls. These canyons once harbored cottonwoods, willows, and springs; the many verdant, secluded glens led John Wesley Powell, the nineteenth-century explorer, to give Glen Canyon its name.

At a public meeting at a Marriott hotel in Page, some 100 people are watching a PowerPoint presentation by Tom Ryan, a hydrologist with the Bureau of Reclamation's Salt Lake City office. The bureau manages Glen Canyon Dam, which creates Lake Powell, and most of the other big engineering projects on the river, including Hoover Dam. Ryan is talking about how the drought is depleting Lake Powell and Lake Mead, 250 miles downriver, and what that means for the millions of people who depend on the approximately 16 trillion gallons stored in the two lakes when they're full. Lake Powell hasn't been full for more than eight years, and no one knows if it will ever be full again.

Ryan's slide show is filled with grim statistics. "This is July 18, 1999," he says, pointing to a spot on a graph of water levels in the reservoir. "The lake was filled to 97 percent of its capacity. In the next five years the reservoir dropped almost 150 feet. Then 2002 -- that was a killer," he continues. "Lake Powell dropped 47 feet, and there was no runoff into the lake at all. It was the second-driest year in 100 years of record keeping on the Colorado River. We reached a low point on April 8, 2005: 33 percent capacity. After 2005 we rebounded a little bit.

"The good news now is that Lake Powell is half full," Ryan says. "But based on this year's snowpack, we won't get above 51 percent. Snowpack basin -- wide above Lake Powell is 50 percent of what it usually is this time of year. The bad news is that we don't know if we're in the eighth year of an eight-year drought or the eighth year of a 15-year drought." Or, I can't help thinking, the eighth year of an arid new era.

Conditions aren't any better at Lake Mead, the only reservoir larger than Lake Powell in the country. Shortly before the meeting begins, I buttonhole Terry Fulp, a colleague of Ryan's at the bureau. "At Lake Mead, we're about 100 feet down from a full pool," Fulp tells me. "We are about 72 feet above the minimum power pool. If we drop below that, we can't generate hydroelectric power."

While the loss of power generated by the Glen Canyon and Hoover dams wouldn't be catastrophic -- together the dams provide less than 10 percent of all power used in the Southwest-the reservoirs' water is crucial. "If Mead were to fall another 122 feet," Fulp tells the audience in Page, "Las Vegas could no longer draw water from the lake. That's about 1.9 million people whose taps wouldn't have water."

To prevent any such disasters, the bureau is modifying some of the most hidebound rules governing the river's use. These are codified in decades of labyrinthine decisions known collectively as the Law of the River, the keystone being the 1922 Colorado River Compact. Congress ratified the compact six years later after long, contentious negotiations among the southwestern states. It divides the states into two basins: an upper basin consisting of Colorado, New Mexico, Utah, and Wyoming; and a lower basin made up of Arizona, California, and Nevada. Each basin now receives half the Colorado's average annual flow, which is further subdivided among the individual states.

In 1922 Las Vegas was an obscure railroad watering stop in the middle of nowhere. The nation was largely rural; no one doubted that the vast share of the water allotted in the compact should go to farms. The compact was written for a world that no longer exists, for a river that seemed inexhaustible. Nevertheless, no one wants to scrap it and become mired in endless lawsuits while hammering out a new agreement.

Until the end of 2007, no incentive existed for any of the states to limit their annual withdrawals from the river. In fact, the system encouraged states to use their full allocation or risk losing the water to another state. The reservoirs could not carry over unused water from year to year, and if water remained unclaimed, other states could request to use it. Throughout the 1980s and 1990s, California lived on this unused water.

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