Environmental effects of historical mining in the Animas River watershed, southwestern Colorado

The U.S. Geological Survey has completed an extensive environmental study of the effects of historical mining on water and sediment quality and aquatic and riparian habitat in the Animas River watershed upstream from Silverton, Colorado. Results from this study are being used by Federal and State agencies and by the local watershed stakeholders group to implement remediation and cleanup activities.

The Watershed Approach provides an effective means to rank and evaluate environmental impact of historical mining throughout a region: The mining-related sites that, upon evaluation, are shown to cause the greatest impact can become the subjects of remediation planning and implementation. This process helps land managers evaluate risk and focus remediation efforts on sites that may be the most deleterious to water quality and aquatic and riparian habitat.