Test results in for Grizzly Reservoir release into Roaring Fork River

Sep 9, 2015


The discoloration of the Roaring Fork River in mid-August was due to a release from Grizzly Reservoir.
Credit Hunter Baar

Results are in from testing done after a release of water from Grizzly Reservoir last month turned the Roaring Fork River a dirty yellow.

The discoloration happened in mid-August after a dam problem forced the release of between 10 and 20 acre feet of water from Grizzly Reservoir on Independence Pass. The water flowed into Lincoln Creek and eventually into the Roaring Fork River. It raised alarm because of its color.

According to tests done by the City of Aspen and the Roaring Fork Conservancy, the water contained elevated levels of dissolved minerals like aluminum, copper and iron. The metals had accumulated in Grizzly, in part, from acid mine drainage from the Ruby Mine.

By the time the water reached Aspen, it had been significantly diluted. Still, tests showed concentrations of aluminum and iron temporarily exceeded state water quality standards meant to protect fish. But, because of the short duration and the dilution of the water, the results conclude it’s unlikely the water pulse will leave long-term impacts.