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USGS Water-Quality Information

USGS Water-Quality Data and Activities for the 2015 Gold King Mine Release



On August 5, 2015, a release of about three million gallons of water and sediment occurred at the Gold King Mine near Silverton, Colorado. At the time of the release, the U.S. Environmental Protection Agency (EPA) was conducting an investigation of the Gold King Mine to assess the on-going water releases from the mine, to treat mine water, and to assess the feasibility of further mine remediation. The EPA planned to excavate the loose material that had collapsed into the cave entry. During the excavation above the old entrance to the underground mine, the loose material gave way, opening the adit (mine tunnel) and pressurized water began leaking above the mine tunnel, spilling the water stored behind the collapsed material into Cement Creek, a tributary of the Animas River.

This web site provides:

  • easy access to USGS data in the area of the release, and
  • updates on recent USGS activities in the area of the release.

Current USGS Activities

USGS scientists from several offices are providing scientific input and collecting data following the release.

Examples of USGS Activities

At the request of the EPA, USGS hydrologists conducted an analysis of streamflow data from USGS streamgages along Cement Creek, Mineral Creek, and the Animas River near Silverton, Colorado. The results were used by EPA to estimate the amount of water released from the Gold King Mine on August 5, 2015.

USGS has collected water and sediment samples:

  • along Cement Creek upstream from Silverton,
  • downstream along the Animas River from Silverton to the confluence with the San Juan River, and
  • downstream along the San Juan River in neighboring New Mexico and Utah.

Refer to the Water-Quality Sampling Data page for all available USGS data.

Historical Data

The upper Animas River watershed near Silverton, Colorado, has been an area of extensive interdisciplinary USGS research on abandoned mine lands. Prior to mining in this area, the mineralized rocks were natural sources of metals and acidity to streams. Historical mining also contributed to the metals and acidity in streams of this area. Multiple USGS papers have been published about the environmental effects of unmined mineralized areas and historical mine sites in the Animas River watershed. These reports, and the data contained therein, provide a critical environmental baseline against which the effects of the Gold King Mine release can be assessed. The locations, types of data, and frequency of data vary based on the objectives of the USGS program or study for which they were collected.

Why do we need data from before the release?

Scientists can use data collected before the August 5, 2015, Gold King Mine release to help answer important questions, including:

  • What were the water-quality conditions in Cement Creek and other downstream water bodies before the release?
  • How did the release affect the water quality downstream?
  • How will we know when downstream water bodies have recovered from the release?


For emergency response information:

For emergency response concerns or questions, please contact the U.S. Environmental Protection Agency (EPA) or call the EPA hotline at 844-607-9700. The USGS is not a regulatory, permitting or enforcement agency; Federal government response to the Gold King Mine is coordinated by the EPA.


Why is the USGS releasing these data now?

USGS historical data linked to from this site were already publicly released by the USGS and available online prior to the August 2015 release. This web site is intended to help Cooperators and interested community members more easily identify and download historical data that may be of relevance to water-quality studies related to the August 5, 2015, release.



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Page Last Modified: Wednesday, 28-Dec-2016 18:55:09 EST