Selected trace-element data for streams in the southern Yampa River basin, northwestern Colorado

Increases in coal mining in northwestern Colorado have increased concerns about the impact of mining on the chemical quality of surface water. One area of particular concern is in the southern part of the Yampa River basin. To identify the possible changes in water quality produced by mining in this area, it is first necessary to determine the present water chemistry resulting from the geology, climate, and land use. Because few data were available, a program for the synoptic collection of water-quality data was developed in which sampling sites were selected to determine the surface-water chemistry. (USGS)