Scenic view of the Upper Animas River watershed, Silverton, Colorado -- one of the watersheds in the USGS Abandoned Mine Lands Initiative.
A small mountain stream impacted by acid mine drainage, Prospect Gulch, Upper Animas River watershed, Colorado.
USGS scientists processing water samples during a stream tracer test on California Gulch, Upper Animas River watershed, Colorado.
Collecting fish samples for toxicity testing with an electrofishing unit in the Upper Animas River, Colorado.
Locating inflows and springs discharging into Mineral Creek, Colorado, prior to conducting a tracer test. Tracer tests are used to assess the relative magnitude of metal loading from inflows along a stream reach.
An abandoned structure and waste-rock pile from the Silverledge Mine adjacent to Mineral Creek, Colorado.
A site of continuous water-quality sampling during a tracer test conducted on the North Fork of the Animas River, Colorado.
View of a data logger used to control a pump that injects a tracer solution into a stream during a stream tracer test.
Collecting invertebrate samples to assess the community composition of a mining-impacted stream, Upper Animas River watershed, Colorado.