The Crystal Valley upstream from Redstone used to be busier than it is today. Ute Indians lived there until prospectors, trappers, ranchers, farmers, and miners forcibly removed them. A small town, which no longer exists, arose to support the settlers, and especially the miners, and for a long time it was the final stop on the Crystal River Railroad, which mainly hauled coal over tracks laid parallel to the river. Marble as white as lard was discovered in the mountains above the valley in the late 1870s. A quarry near what became the town of Marble supplied the raw material for the Tomb of the Unknown Soldier, which was carved from a single block, and the exterior of the Lincoln Memorial; today, most of its customers are in Europe and Asia. The gunfighter Doc Holliday lived in a borrowed cabin in the valley for a few months in 1887, futilely seeking relief from tuberculosis; he died that same year in a bed in a hotel room in Glenwood Springs, thirty miles down the river, and his last words were “Well, I’ll be damned. This is funny.” (He hadn’t expected to die in bed, with his boots off.)

The railroad tracks were taken up in 1942 and recycled as war matériel, and most of the Crystal Valley between Redstone and the river’s headwaters is currently relatively unmolested—a rarity among river basins of any size in Colorado. Since the 1980s, a coalition of conservationists has sought to have that section of the river designated “Wild and Scenic,” in accordance with a 1968 act of Congress that extends federal protections to rivers that flow freely, possess certain “Outstandingly Remarkable Values,” and meet other requirements. (The only river in the state with that designation currently is the section of the Cache la Poudre west of Fort Collins.) The original impetus for seeking protected status was a proposal, in the 1980s, to build two large dams, one a few miles above Redstone Inn and the other a little more than two miles below it. That proposal was a revived and modified version of the West Divide Project, which Congress approved in the 1960s but never funded. A few years ago, the Colorado River Water Conservation District, a state agency, tried again, this time with a proposal for a dam, a reservoir, and a power plant a short distance upstream from the inn. Mary Harris and Delia Malone were part of the group that defeated that proposal. They are both officers of the Roaring Fork chapter of the Audubon Society, and Malone is an ecologist and a research associate in the Colorado Natural Heritage Program of Colorado State University. They had agreed to show me where the dam was supposed to have gone.

We met in the parking lot of the Redstone Inn. Harris was wearing a maroon-and-black down jacket, and Malone was wearing a black down vest and gray yoga pants. (The morning was chilly.) Malone had brought her dog, a black Labrador retriever, and she had tied two strips of orange plastic to its collar, to protect it from hunters. We all got into Harris’s SUV and drove up the valley—and it’s a good thing we didn’t take my car, I realized later, because when I started it the CD player would have picked up at an especially embarrassing moment in Game of Thrones, in the middle of the wedding night of Daenerys Targaryen and Khal Drogo. Arranged on a blue rubber mat on Harris’s dashboard was a grouping of toy-soldier-size figures: angry farmers or townspeople from an unspecifiable foreign country and era, perhaps the ones who gathered with torches outside Castle Frankenstein and cursed Boris Karloff. The male figures were wearing hats and the female ones were wearing headscarves, and each was holding a weapon: a cleaver, a rolling pin, a rake, a pitchfork, a long knife, a rifle. Crouched near their feet were two green winged creatures, which looked a little like the flying monkeys in The Wizard of Oz. There was also an out-of-scale Uncle Duke, the Hunter S. Thompson character from the comic strip Doonesbury; he was wearing a T-shirt that said “Death Before Unconsciousness.” Thompson, who died in 2005, lived in Woody Creek, a few miles away. The display represented Harris’s exasperation with environmental desecraters.

A couple of miles upriver from the inn, tall rock walls pinched in on both sides of the road, and a little ways beyond that opening the valley broadened into an enormous mountain meadow, within which the Crystal had spread out into a maze of streams and ponds and grassy islands and meanders. We parked at a turnout and walked down a path to the edge of the water. On the far side of the valley, near the top of a dead spruce tree, I saw a pair of great blue heron nests, one above the other: huge, messy-looking saucers of silvery sticks. Harris thought she saw a bald eagle—Malone had seen one flying near the same spot the day before—but after passing binoculars back and forth we decided that the eagle was actually just sunlight glinting off a leafless branch. We did see an American dipper and a belted kingfisher, and, as we stood on the bank looking at other birds, the dog sat at Malone’s feet and seemed to look, too.

We saw many signs of beavers, including a couple of lodges they’d erected beside broad meanders on the far side of the valley. Indeed, the entire section of river before us, as well as the meadow it flowed through, had been shaped by beavers over many generations. Dam-building is instinctive in beavers and may be triggered by flowing water, or the sound of flowing water. A similarly irresistible urge seems to be inborn in hydraulic engineers. I could easily picture the architects of the West Divide Project standing where we were standing and mentally adding up acre-feet. “It’s the perfect place for a reservoir,” Malone said. “They wouldn’t have had to do much. That gap we drove through is the ideal spot for a dam.” The valley floor even looked a little like the bottom of a lake.

Where the Water Goes: Life and Death Along the Colorado River