Earth Notes: Dolores Flume

May 8, 2019

At the confluence where the San Miguel the Dolores rivers, beams and hoists zipper a section of streaked, vertical sandstone cliff on river right.  They’re what remain of an open water chute, or “hanging flume.”

Dolores Flume
Credit CC, Wikimedia

The Dolores Flume in southwest Colorado is twelve miles long, built from ponderosa planks and iron rods. It siphoned water from behind a San Miguel dam near the town of Uravan, to the Montrose Placer Mine Company’s gold deposits along the Dolores.  

Lumber for the flume was lowered from the rim on a winch-powered cable. Workers suspended from ropes built the hydraulic project over three years, finishing in 1891.

   Prospectors and cattlemen flocked to the newly ceded Colorado territories, and in 1896, discovery of the uranium compound carnotite launched the first of several mining booms in the Dolores River country. Ore processing required large quantities of water—so did irrigation, which still puts a big demand on the river.

   The flume, conveying the contents of about 120 Olympic-size pools per day, operated for only three years. The Lone Tree mine gold was found to be unrecoverable, and the abandoned flume was scavenged for construction materials.

In 2006, the World Monuments Fund listed it among one hundred sites most in need of preservation and funding. Six years later researchers rappelled down the cliff to gauge the flume’s state of preservation and study construction details. An eighty-foot segment was rebuilt, but people wondered how the workmen sunk 18-inch holes into the cliff without power drills?

For river parties floating past, the Dolores Flume still raises such mysteries.