I am sitting next to a 200-foot high concrete apparition. Matilija Dam, not far from the California coast, sits astride the narrow canyon of the Ventura River amid the velvet green foothills of the Santa Ynez Mountains. At the entrance to the dam site, razor wire conspicuously adorns the top of a fence, just above a sign that says "DANGER RAZOR WIRE," as though visitors might not have noticed already that the dam looks more like a concentration camp than a public utility. The control tower’s windows are smashed, and rusting cables and slashed wires hang from the abutments. Falling boulders have smashed the staircase that ascends to the control tower, and the face of the dam is a filigree of cracks. This area has the geologic stability of a stack of greased bowling balls. One good shake of Mother Earth, and this dam is beach fill.

The current lessee of Matilija Dam, the Casitas Municipal Water District, based in nearby Oak View, Calif., would prefer that the public not see this concrete disaster. Numerous signs warn: "trespassing loitering prohibited by law." But I decide to loiter anyway, because I am fascinated by doomed dams: They presage the future. Just as surely as dams were once symbols of progress and the "conquest" of nature, some of them are now symbols of the excesses of the past. Nature, and a new political dynamic, are dismantling some dams. A dam slated for the wrecking ball is a kinetic form of politics — falling concrete that embodies the energy of a whole new concept of river management. As dams fall, hopes rise — a stark exchange of the past with the future.

I sit down beside one of the no-trespassing signs to rest, utterly alone. I see a piece of concrete from the dam, about the size of a fist, and put it in my pack, a souvenir of the world’s largest dam to be slated for removal, so far. At my feet are 16,000-pound chunks of concrete that have already been torn from the lip of the structure, some of them during a visit by former Interior Secretary Bruce Babbitt in 2000. Babbitt is no longer secretary, but this dam will continue its demise without him, the inevitable result of changing values and the law of gravity.

Spring rains have raised the shallow pool of water behind the dam (no one would seriously call it a reservoir), and water is spilling over the rim, creating a series of translucent sheets of water that drop gracefully down the face of the dam. The reservoir bed is filled with six million cubic yards of sand, silt and rock —material that once went to build up Ventura Beach. For the last half-century, this beach fill has been trapped in this canyon behind Matilija Dam, and as a result, Ventura Beach is slowly eroding into the sea. Even the surfers’ association lobbied to have the dam removed. The Santa Ana winds are gusting forcefully, and the falling water twists into swirls and drifts. The dark, dilapidated face of the dam is marked with large red circles painted at strategic joints; they look vaguely like targets, as though the dam owners are hoping someone will blow this thing to dam heaven and save a lot of time and money. But this is no monkey-wrench target; if the dam failed, the meager amount of water stored behind it would create no more than a spring freshet downstream.

Matilija is a dam that stores no water, generates no electricity, and offers no recreation. It is utterly, irrevocably useless, other than to serve as a reminder of a time when America built dams willy-nilly without considering their long-term impact or utility. It may be hard to imagine, but this is the future facing every dam in the world. Sooner or later, every dam crumbles.

Two months later, I am walking along the top of Elk Creek Dam, which spans a beautiful mountain stream in southern Oregon. I kick up a fine dust of weathered concrete that settles on the weeds growing from cracks. This is a dam so pointless, so obviously irrational, that even the Corps of Engineers — the Dams-R-Us agency — did not want to build it, and when forced to do so, completed only one-third of the job and quit.

Up- and downstream from the dam, this little valley is a verdant natural paradise. The river courses briskly through dark volcanic rock and dense stands of pine and Douglas fir. But the dam site is an industrial nightmare. It is strewn with giant piles of crushed rock and gravel, placed there by the Corps to complete the last two-thirds of the dam, but never put to use. Rusting rebar juts from the unfinished escarpment, and the rolled concrete fill is spalling badly.

Elk Creek Dam is the perfect example of pork-barrel water politics, born in an age when politicians equated dam building with re-election. The first standard bearer for the dam was Mark Hatfield, senator from Oregon from 1967 to 1997. According to some sources, Hatfield promised his constituents that he would get the funding to build Elk Creek Dam. When the Corps of Engineers recommended against building the dam, which would produce no hydropower or water supply, and provide only a slim margin of flood control, Hatfield put money for it in an appropriations bill anyway.

The Corps, a military unit, dutifully followed orders. It started digging keyways and pouring concrete. When representatives from an environmental group met with Corps personnel to discuss Elk Creek, a Corps staff member expressed his frustration, asking the environmentalists, "Isn’t there anything you can do to get Hatfield off our backs?"

There was: Environmental groups sued the Corps for failure to complete an adequate environmental impact statement. They were unsuccessful in the district court, but prevailed at the appeals level. That gave the Corps the excuse it needed; the agency turned its back and walked away from the construction site, leaving building materials lying around as though it planned to resume work the next day.

That was in 1987 — 17 years ago. Now, the unfinished dam just sits there, blocking salmon and steelhead migration on the river. The Corps is now operating an expensive trap-and-haul system, catching fish on their way upstream to spawn, dumping them into trucks, and driving them around the dam — a scheme that has Rube Goldberg written all over it. Efforts to remove or "notch" the dam have been stymied by some local politicians and Congressman Greg Walden, who still see dams as the key to future development. They hope that some day the dam will be finished and provide additional water storage for area farmers. Elk Creek Dam is a symbol of how difficult it is to change a mindset and overcome the inertia of a hundred years of pork-barrel water policy.

Later, in the fall, I head to Escalante Canyon in southern Utah. If this canyon was anywhere else in the United States, it would be a national park. But it had the misfortune of running into the Colorado River upstream of Glen Canyon Dam, and thus the most impressive part of the canyon was submerged under Lake Powell. I have come here with members of the Glen Canyon Institute, a group with the unthinkable idea of draining Lake Powell and restoring Glen Canyon (HCN, 12/22/03: Massive logging plan shakes Northwest). The Bureau of Reclamation will not even discuss draining the lake, but Mother Nature seems to have other ideas: After five years of drought, the reservoir is at less than half capacity.

Most of Glen Canyon’s 96 side canyons are marked with buoys, like street signs at busy intersections. Our motorboat takes a hard right turn into the Escalante Arm and enters a maze of side streams, dead-end cirques, and spiraling rock buttresses. We pause for traffic to clear, turn left into Davis Gulch, and slow the motor to a crawl. Still, our wake bounces off the narrow rock walls and rolls back and forth across the channel.

We follow this avenue of water, its surface like green polished marble, around innumerable switchbacks and meanders. All the while, the water channel becomes more confining while the surrounding walls remain high and often over-hanging. It’s as though we are descending into a cleft in the crust of the earth itself. After a mile or two, we come to a sandy beach that stretches across the canyon — the end of this arm of the reservoir. Perhaps a hundred feet above us, we can make out the high-water mark on the canyon wall. We have come to see some of the revealed landscape that has emerged from the depths of the reservoir.

We beach the boat and begin walking on ground that has not been trod since Mickey Mantle was in his prime. The area closest to the current water line is practically devoid of vegetation, but nascent sprigs of grass, tamarisk, and willow are sprouting a little farther upstream. As we hike up-canyon, the typical array of canyon flora begins to appear in profusion. After half a mile, we are in a part of the canyon that has been above water for perhaps two years. A meadow has formed on both sides of the stream; evening primrose, prickly pear, and globemallow compete for space. Across the creek, a dense copse of young cottonwood trees crowds the bank, some of them six feet tall.

We can guess how long this area has been free of the reservoir because of the graffiti on the rocks above us; boaters spray-painted their names and the year they visited — two years ago — on the cliff above their lakeside fire ring. The fecundity and regenerative power of the canyon are spectacular, especially compared to the dead zone that immediately surrounds the reservoir’s edge. The great push and rush of spring floods has fed a rich load of seeds, soil and moisture into these previously drowned areas, bringing them to life in just a season or two. Canyon country is fragile, but it does have a habit of aggressively reclaiming its own. Davis Gulch is coming alive, recovering its natural green velour and its complex web of desert life.

There are 76,000 dams in this country over six feet in height, and another 2.5 million smaller dams. The United States entered the dam-building era the way it sometimes goes to war — bold and headstrong, with no understanding of the ultimate costs. For the first 200 years of this country’s history, dams were synonymous with prosperity and stability. But dams also destroyed entire ecosystems, and replaced living rivers with stagnant reservoirs. We dismembered rivers and divvied up the component parts without realizing the value of the rivers themselves.

But the canyons and rivers are still there, below the reservoirs. Extinction is forever; dams are not. This provides us with an opportunity to engage in the politics of healing rivers and restoring riverine landscapes. We can always find another source of energy, a more sensible place to grow high-water crops, and a more efficient way to water our cities. But we cannot replicate Glen Canyon; we cannot genetically engineer a massive salmon run; we cannot invent a mountain canyon that funnels sand to the edge of a continent. We have great power to foul our own nest, but we have a commensurate power to mend that nest, and create a future of free-flowing rivers and deeply carved canyons.

In years to come — maybe 100 or 200 years from now — when a free-flowing river is no longer as rare as a quiet moment, people will stand on the edge of the Ventura River, or Elk Creek, or the Colorado River running wild again through Glen Canyon, and marvel at the grandeur. They may even give thanks to their ancestors for having the foresight to save America’s rivers for them.

Daniel McCool is a professor of political science and director of the American West Center at the University of Utah.