Dolores River

The Dolores River is the river that almost never runs. Rising in the San Juan Mountains near Rico, Colorado, the Dolores flows 250 miles northwest to the Colorado River near Gateway — but McPhee Dam, completed in 1984, captures almost the entire flow for agricultural use in the Montezuma Valley. In most years, the river below the dam is dewatered to a trickle. But in big snowpack years — when McPhee Reservoir fills and the Bureau of Reclamation has no choice but to release — the Dolores comes alive. The 100-mile Bradfield Bridge to Bedrock run is one of the great multi-day wilderness trips in the American West: red sandstone canyons, Class II-IV whitewater, ponderosa pine benches, and a sense of earned remoteness that comes from running a river that may not run again for years. The Dolores is a boom-or-bust proposition. You watch the snowpack reports all winter. You watch the reservoir fill all spring. And when the call comes that they’re releasing, you go — because it might be three or five years before it happens again.

The Dolores cuts through the same Mesozoic sandstone sequence visible throughout the Colorado Plateau — Wingate, Kayenta, Chinle — but with the added geological complexity of the Paradox Formation salt anticlines. The river flows through Paradox Valley perpendicular to the valley's axis, one of the most unusual drainage patterns in Colorado, created when the river cut through the salt anticline faster than it collapsed. Slickrock Canyon exposes deep red Cutler Formation sandstone in one of the most dramatic canyon settings on the plateau.

The Dolores supports endangered Colorado pikeminnow and razorback sucker, but McPhee Dam has severely altered the natural flow regime these species depend on. Tamarisk beetle biocontrol has shown progress in some canyon reaches. Ponderosa pine benches along the canyon rim create a distinctive ecological transition not found on most Colorado Plateau rivers.