Water-Quality Characteristics for Sites in the Tongue, Powder, Cheyenne, and Belle Fourche River Drainage Basins, Wyoming and Montana, Water Years 2001-05, with Temporal Patterns of Selected Long-Term Water-Quality Data

Abstract

Water-quality sampling was conducted regularly at stream sites within or near the Powder River structural basin in northeastern Wyoming and southeastern Montana during water years 2001-05 (October 1, 2000, to September 30, 2005) to characterize water quality in an area of coalbed natural gas development. The U.S. Geological Survey, in cooperation with the Wyoming Department of Environmental Quality, characterized the water quality at 22 sampling sites in the Tongue, Powder, Cheyenne, and Belle Fourche River drainage basins. Data for general hydrology, field measurements, major-ion chemistry, and selected trace elements were summarized, and specific conductance and sodium-adsorption ratios were evaluated for relations with streamflow and seasonal variability. Trend analysis for water years 1991-2005 was conducted for selected sites and constituents to assess change through time. Average annual runoff was highly variable among the stream sites. Generally, streams that have headwaters in the Bighorn Mountains had more runoff as a result of higher average annual precipitation than streams that have headwaters in the plains. The Powder River at Moorhead, Mont., had the largest average annual runoff (319,000 acre-feet) of all the sites; however, streams in the Tongue River drainage basin had the highest runoff per unit area of the four major drainage basins. Annual runoff in all major drainage basins was less than average during 2001-05 because of drought conditions. Consequently, water-quality samples collected during the study period may not represent long-term water-quality conditions for all sites. Water-quality characteristics were highly variable generally because of streamflow variability, geologic controls, and potential land-use effects. The range of median specific-conductance values among sites was smallest in the Tongue River drainage basin. Median values in that basin ranged from 643 microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25°C) on the Tongue River to 1,460 µS/cm at 25°C on Prairie Dog Creek. The Tongue River drainage basin has the largest percentage of area underlain by Mesozoic-age and older rocks and by more resistant rocks. In addition, the higher annual precipitation and a steeper gradient in this basin compared to basins in the plains produce relatively fast stream velocities, which result in a short contact time between stream waters and basin materials. The Powder River drainage basin, which has the largest drainage area and most diverse site conditions, had the largest range of median specific-conductance values among the four major drainage basins. Median values in that basin ranged from 680 µS/cm at 25°C on Clear Creek to 5,950 µS/cm at 25°C on Salt Creek. Median specific-conductance values among sites in the Cheyenne River drainage basin ranged from 1,850 µS/cm at 25°C on Black Thunder Creek to 4,680 µS/cm at 25°C on the Cheyenne River. The entire Cheyenne River drainage basin is in the plains, which have low precipitation, soluble geologic materials, and relatively low grad...

Potential water-quality effects of coal-bed methane production water discharged along the upper Tongue River, Wyoming and Montana

“…Conditions in the upstream watersheds that affected the export of water and dissolved ions to the Tongue River during the synoptic sampling trips may have been different historically and may be different in the future. For instance, the trend in SC in Goose Creek at a site near Sheridan, Wyo., was small but significantly upward between 1991 and 2005 (Clark and Mason, 2007). The watershed conditions that could affect the export of dissolved ions could include, for instance, climate, land use, irrigation and other agricultural practices, water management, and CBM development.…”

Assessment of ecological conditions and potential effects of water produced from coalbed natural gas development on biological communities in streams of the Powder River structural basin, Wyoming and Montana, 2005-08

“…Water-quality characteristics of streams in the Powder River structural basin are variable largely because of streamflow and geology (Clark and Mason, 2007). The Tongue River drainage basin has its headwaters in the Bighorn Mountains, which are characterized by relatively high precipitation, low evaporation, and resistant igneous, metamorphic, and Paleozoic-era sedimentary rocks (Clark and Mason, 2007).…”

“…Water-quality characteristics of streams in the Powder River structural basin are variable largely because of streamflow and geology (Clark and Mason, 2007). The Tongue River drainage basin has its headwaters in the Bighorn Mountains, which are characterized by relatively high precipitation, low evaporation, and resistant igneous, metamorphic, and Paleozoic-era sedimentary rocks (Clark and Mason, 2007). In contrast, the Powder River drainage basin has a large part of its headwaters in the plains, which are characterized by relatively low precipitation, high evaporation, and soluble Tertiary-age sedimentary rocks (Clark and Mason, 2007).…”

“…The Tongue River drainage basin has its headwaters in the Bighorn Mountains, which are characterized by relatively high precipitation, low evaporation, and resistant igneous, metamorphic, and Paleozoic-era sedimentary rocks (Clark and Mason, 2007). In contrast, the Powder River drainage basin has a large part of its headwaters in the plains, which are characterized by relatively low precipitation, high evaporation, and soluble Tertiary-age sedimentary rocks (Clark and Mason, 2007). Different basin characteristics of the Tongue River and Powder River are reflected in the range of mean values for specific conductance, dissolved sodium, and alkalinity for ATG sampling events during the relatively low flow conditions of summer ( fig.…”

Application of a Bayesian model to infer the contribution of coalbed natural gas produced water to the Powder River, Wyoming and Montana

“…Two studies, however, examined historical water quality data from the Powder River to determine whether there were changes that may be attributed to development of CBNG activity in the PRB. Clark and Mason () could not establish a causal link with gas production and instead established that streamflow was the strongest control on water quality. Statistical analysis of historical water quality data by Wang et al .…”