Natural and anthropogenic factors influence water-quality conditions in the Yellowstone River Basin. Physiography parallels the structural geologic setting that is generally composed of several uplifts and structural basins. Contrasts in climate and vegetation reflect topographic controls and the midcontinental location of the study unit. Surface-water hydrology reflects water surpluses in mountainous areas that are dominated by snowmelt runoff, and arid to semiarid conditions in the plains that are dissected by typically irrigated valleys in the remainder of the study unit. Principal shallow aquifers are Tertiary sandstones and unconsolidated Quaternary deposits. Human population, though sparsely distributed in general, is growing most rapidly in a few urban centers and resort areas, mostly in the northwestern part of the basin. Land use is areally dominated by grazing in the basins and plains and economically dominated by mineral-extraction activities. Forests are the dominant land cover in mountainous areas. Cropland is a major land use in principal stream valleys. Water use is dominated by irrigated agriculture overall, but mining and public-supply facilities are major users of ground water. Coal and hydrocarbon production and reserves distinguish the Yellowstone River Basin as a principal energy-minerals resources region. Current metallic ore production or reserves are nationally significant for platinum-group elements and chromium. The study unit was subdivided as an initial environmental stratification for use in designing the National Water-Quality Assessment Program investigation that began in 1997. Ecoregions, geologic groups, mineral-resource areas, and general land-cover and land-use categories were used in combination to define 18 environmental settings in the Yellowstone River Basin. It is expected that these different settings will be reflected in differing water-quality or aquatic-ecological characteristics.

Montana, North Dakota, Wyoming↗

USGS1975

Water-resources investigations of the U.S. Geological Survey in the northern Great Plains coal region of Wyoming, Montana, and North Dakota, 1975

The Geological Survey's Water Resources Division has for many years maintained a program of water-resources investigations that includes the coal regions of Wyoming, Montana, and North Dakota. These programs have been supported by State and local agencies and by other agencies of the Federal government, largely to provide data for water-resources development projects, allocations of water, and to inventory of water resources for future planning. The recent interest in coal has added new dimensions and greater intensity to the investigations. The work has expanded to include monitoring the environmental effects of coal mining and processing and to determine the availability of additional water supplies for coal-conversion plants and related demands. New objectives are now reflected in the program. Much of the work is to assist the Bureau of Land Management in its responsibilities to minimize the possible detrimental effects of coal mining on the public resource lands. The Environmental Protection Agency also supports a significant part of the program. Their support is to assure that water-quality information is collected at key locations, with types of water-quality data and frequency of sampling needed by that agency in the discharge of its function. Relatively large increases in the program have been funded by direct appropriation to the Geological Survey. This report describes the water-resources investigation program that is currently in operation. Locations of gaging stations and water-quality measuring sites, frequencies and parameters, and areas of groundwater studies are included in this report. Brief descriptions of coal-related studies by investigators who are headquartered outside the Northern Great Plains coal regions are also included. Such studies are research in topics related to coal extraction, water supply, and post-mining reclamation

Montana, North Dakota, Wyoming↗