Skip to main content
U.S. flag

An official website of the United States government

Interim report on the scientific investigations in the Animas River watershed, Colorado to facilitate remediation decisions by the U.S. Bureau of Land Management and the U.S. Forest Service, March 29, 2000 meeting, Denver, Colo.

July 1, 2001

The joint U.S. Department of the Interior and U.S. Department of Agriculture Abandoned Mine Lands
Initiative (AMLI) was developed as a collaborative effort between the Federal land management agencies (FLMA,
that is the U.S. Bureau of Land Management and the U.S. Forest Service) and the U.S. Geological Survey (USGS)
in 1996. The stated goal of the AML Initiative was to develop a strategy for gathering and communicating the
scientific information needed to develop effective and cost-efficient remediation of abandoned mines within the
framework of a watershed. Four primary objectives of the AMLI are to:
1. Provide the scientific information needed (in the short-term) by the FLMAs to make decisions related to the
design and implementation of cleanup actions,
2. Develop a multi-disciplined, multi-division approach that integrates geologic, hydrologic, geochemical and
ecological information into a knowledge base for sound decision making,
3. Transfer technologies developed within the scientific programs of the USGS to the field and demonstrate
their suitability to solve real, practical problems, and
4. Establish working relationships among involved members of land management and regulatory agencies
within the framework of a watershed approach to the cleanup of abandoned mines.
Long-term process-based research, including development of analytical tools, is recognized as being critical to the
long-term success in remediating watersheds impacted by historical mining activities (AML 5-year plan,
In a meeting of Federal agencies (U.S. Bureau of Land Management [BLM], U.S. Bureau of Reclamation
[BOR], U.S. National Park Service [NPS], U.S. Forest Service [USFS], the U.S. Environmental Protection Agency
[EPA], the U.S. Fish and Wildlife Service [F&WS]), and State agencies (Colorado Division of Public Health and
Environment, Colorado Division of Mines and Geology), several watersheds were examined within the state whose
water quality was presumed to be impacted by historical mining activities. The Animas River watershed (fig. 1) was
selected by the State and Federal agencies as one of two watersheds in the U.S. to be studied in detail by the USGS
in the AML Initiative. Beginning in October 1997, each of the four Divisions of the USGS (Water Resources,
Geologic, Biological Resources, and National Mapping) initiated a collaborative integrated science study of the
watershed. Funds were provided from USGS base funding to each of the four Divisions in response to the priorities
set by Congressional action and within the flexibility provided by the budgetary framework funding individual
research programs. The AML Initiative provides for a five-year focused scientific effort in the two watersheds with
final synthesis of the scientific results from each to be published in 2001. Publications are released on the AML web
site on a regular basis (
On March 29, 2000, the USGS hosted a meeting for the BLM and USFS to discuss remediation options that
were under consideration for the summer of 2000. The purpose of this report is to provide an overview of the
scientific rational provided by the USGS to meet objective one above, and to summarize our preliminary
interpretations of our data. Additional information from sites on private lands have been collected by the State of
Colorado, EPA, and the ARSG. Unfortunately, these data have not been fully supplied to the USGS so our
conclusions are based only upon our data. These interpretations provide science-based constraints on possible
remediation options to be considered by the FLMA, the State, and local property owners in the Animas River
watershed. The report is presented in outline format to facilitate discussion of remediation options at the March 29,
2000 meeting. Not all historical mining sites within the watershed are on public lands. This should not be construed
to be a final report of the USGS