The U.S. Geological Survey (USGS) conducted an Abandoned Mine Lands (AML) Initiative during the fiscal years 1997 through 2001 to provide technical assistance in support of Federal Land Management Agency (FLMA) actions to remediate contamination associated with abandoned hard rock mining activities. This initiative was part of a larger strategy by the U.S. Department of the Interior and the U.S. Department of Agriculture to coordinate activities for the cleanup of federal lands affected by AML. The strategy employed a watershed approach, in which contaminated sites were identified and remediated based on their effect on the water and ecosystem quality of a targeted watershed. The initiative was implemented on a pilot scale in two watersheds, [...]