Dolores River

The Dolores River is a tributary of the Colorado River, approximately 250 mi (402 km) long, in the U.S. states of Colorado and Utah.

It rises in southwestern Colorado near Dolores Peak and Mount Wilson in the San Miguel Mountains. It flows southwest, past the town of Dolores, where it turns, flowing north and northwest. It flows through the Dolores River Canyon, then cuts across Paradox Valley before receiving the San Miguel River (incidentally, both the Dolores and the San Miguel have their headwaters to either side of Lizard Head Pass) in Montrose County and crossing into Utah, where it joins the Colorado in Grand County near the former Dewey Bridge.

The river was explored and possibly named by Juan Maria Antonio Rivera during an 1765 expedition from Santa Fe.

The Dolores is navigable by rafts and kayaks (up to class IV) from McPhee Reservoir to its confluence with the Colorado. When water is restricted from the reservoir it may be possible to boat down stream from the San Miguel River. However, the river is extensively used for irrigation and during low water years is wholly unnavigable. The mean annual flow of the Dolores is approximately 1,240 cu ft/s (35 m3/s).

In high-runoff years, the section from Bradfield Ranch near Cahone, Colorado down to Slickrock, Colorado, offers scenery, camping, and rapids for inflatables and kayaks. The section from Slickrock to Bedrock, Colorado goes through the goosenecks of a sandstone canyon with several mostly class II rapids. The Bureau of Land Management recommends minimum flows of 200 cubic feet per second (5.7 m3/s) for canoes, kayaks, and inflatable kayaks, 800 cu ft/s (23 m3/s) for small rafts of up to 14 feet (4.3 m), and 1,000 cu ft/s (28 m3/s) for larger rafts of up to 18 feet (5.5 m) in size. The BLM does not require permits for groups running the river in Colorado, though permits are required from the Moab BLM office for boaters wishing to make the run from Gateway, CO into Utah and to the confluence with the Colorado River near Dewey Bridge. In 2010, flash flooding altered Diversion Dam Rapid and Stateline Rapid on this section, making the latter very difficult to run in any vessel larger than a kayak.

Dam releases from McPhee reservoir are a controversial topic. Currently, the Bureau of Reclamation, which manages the dam, operates it on a "fill, then spill" policy, where the dam is filled first, and only then if any "extra" water is available are larger flows released for recreational boaters. This fact aggrieves recreational boaters, who claim it is difficult for anyone but a local resident closely watching the gauges to plan trips in advance on the river. The San Juan Citizens' Alliance has worked to start a dialogue between Dolores River stakeholders in the hopes of shifting release policy to one that allows for greater, planned releases.

• Diversion Dam Rapid in 2011 at 700 cfs

• Historic hanging flume clings precariously to canyon walls

• The Dolores river at low water, ~250 cfs