Water-quality data for streams in the Boulder River Watershed, Jefferson County, Montana

Chemical data were collected in the Boulder River watershed of southwestern Montana during 1996-99 as part of a detailed interdisciplinary study characterizing the effects of historical inactive mines on streams in the watershed. This report presents water-quality data collected by the U.S. Geological Survey for physical properties, major ions, nutrients, and trace elements for 62 sites in and near the watershed. Supplementary historical water-quality data for 83 sites also are presented.