From December 1975 to September 1977 the U.S. Geological Survey studied coal mine drainage in western Washington to 1) characterize the water quality of drainage from abandoned mines in the 11 coal-bearing areas of the State; 2) examine the water quality effects on a stream receiving drainage from an abandoned coal mine; 3) determine the baseline water-quality conditions at two prospective underground coal mine areas; and 4) recommend procedures for monitoring stream quality in the baseline areas in the event that mining occurs. This report presents physical, chemical, and biological data collected during the study period from Gallop Creek (Whatcom County), Loretta Creek (Skagit County), and Wilkeson Creek (Pierce County) and from 100 abandoned coal mines in western Washington, and from a borehole hydraulic-mining test site. Biological information included taxonomic identifications and counts of benthic invertebrates and periphytic algae. (USGS)