Increases in coal mining in Colorado have raised questions regarding the impact of mining on the quality of surface water. An area where increases have caused particular concern is in northwestern Colorado, in the southern part of the Yampa River basin. In order to identify the changes produced by mining in the area it is necessary first to identify the water chemistry resulting from the geology, climate, and land use. To answer the above questions, a program for the synoptic collection of water-quality data was developed in which a network of sampling sites was established to determine the surface-water chemistry.
This study was begun in April 1981. Water-quality samples were collected from sites on all continuously flowing streams in the southern part of the Yampa River basin from the Oak Creek drainage near Steamboat Springs on the east to the surface-water gaging station on the Yampa River near Maybell on the west. Each water-quality site was sampled repetitively as changes occurred in discharge and specific conductance. Water-quality data from surface-water gaging stations in the area for water years 1976 to 1981 are included in the report.