In October 1975 the U.S. Geological Survey established a network of nine data-collection stations on eight streams in Montana to monitor water quality in potential coal-mining areas. The report summarizes and evaluates the water-quality data that have been collected during the first 2 years (3 years for 1 station) of network operation. Big Dry Creek, Little Dry Creek, Timber Creek , and Nelson Creek are the principal streams forming the Big Dry Creek basin, which is tributary to the Missouri River. These streams all contain water of the sodium sulfate type. Concentrations were high for dissolved solids (433-4,570 mg/L) and generally low for nutrients and trace elements. Prairie Elk Creek, Sand Creek, and the Redwater River flow directly into the Missouri River. Prairie Elk and Sand Creeks have mainly sodium bicarbonate water, whereas the Redwater River is predominately sodium sulfate water. All three streams contained water of high dissolved-solids concentration (160-3,370 mg/L) and generally low nutrient and trace-element concentrations. Burns Creek is tributary to the Yellowstone River. The water type is generally sodium sulfate during the spring and summer and sodium bicarbonate during the fall and winter. Water from Burns Creek ranged from 382 to 1,420 mg/L dissolved solids. (Woodard-USGS)
