Tom Cleasby
Science and Products
Wyoming-Montana Stream Water-Quality Network - Water Year 2020
The USGS monitors stream water quality in Wyoming and Montana in cooperation with State, County, local, and other Federal agencies. Water-quality data for these sites are available from the USGS National Water Information System Web Mapper application in the form of an interactive map that can be accessed from the Data and Tools tab.
Clark Fork Water-Quality Monitoring
The U.S. Geological Survey (USGS) has collected water-quality samples from selected stream sites upstream from Missoula since 1985. Sampling was initiated in response to elevated trace-element concentrations and the designation of areas in the upper Clark Fork basin by the U.S. Environmental Protection Agency (USEPA) as National Priorities List...
Quantification of trace element loading in the upper Tenmile Creek drainage basin near Rimini, Montana, September 2011
The principle sources of trace elements entering upper Tenmile Creek, Montana, during September 2011, four trace metals and the metalloid arsenic, were identified and quantified by combining and analyzing streamflow data determined from tracer injection with trace-element concentrations and related water-quality data determined from synoptic...
Cleasby, Tom; Eldridge, Sara L. Caldwell
Water-quality, bed-sediment, and biological data (October 2016 through September 2017) and statistical summaries of data for streams in the Clark Fork Basin, Montana
Water, bed sediment, and biota were sampled in selected streams from Butte to near Missoula, Montana, as part of a monitoring program in the Clark Fork Basin of western Montana. The sampling program was led by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to characterize aquatic resources in the Clark...
Cleasby, Tom; Hornberger, Michelle I.; Heinert, Terry L. ; Turner, Matthew A.
Water-quality trends for selected sites in the Boulder River and Tenmile Creek watersheds, Montana, based on data collected during water years 1997-2013
In the Boulder River and Tenmile Creek watersheds in southwestern Montana, there was intensive mining during a 40-year period after the discovery of gold in the early 1860s. Potential effects from the historic mining activities include acid-mine drainage and elevated concentrations of potentially toxic trace elements from mining remnants such as...
Sando, Steven K.; Clark, Melanie L.; Cleasby, Tom; Barnhart, Elliott P.
Diel mercury-concentration variations in streams affected by mining and geothermal discharge
Diel variations of concentrations of unfiltered and filtered total Hg and filtered methyl Hg were documented during 24-h sampling episodes in water from Silver Creek, which drains a historical gold-mining district near Helena, Montana, and the Madison River, which drains the geothermal system of Yellowstone National Park. The concentrations of...
Nimick, David A.; McCleskey, R. Blaine; Gammons, C.H.; Cleasby, Tom; Parker, S.R. Influence of in-stream diel concentration cycles of dissolved trace metals on acute toxicity to one-year-old cutthroat trout (Oncorhynchus clarki lewisi)
Extrapolating results of laboratory bioassays to streams is difficult, because conditions such as temperature and dissolved metal concentrations can change substantially on diel time scales. Field bioassays conducted for 96 h in two mining‐affected streams compared the survival of hatchery‐raised, metal‐näive westslope cutthroat trout (...
Nimick, David A.; Harper, David D.; Farag, Aida; Cleasby, Tom; MacConnell, Elizabeth; Skaar, D. Diel cycles in dissolved metal concentrations in streams: Occurrence and possible causes
Substantial diel (24‐hour) cycles in dissolved (0.1‐μm filtration) metal concentrations were observed during low flow for 18 sampling episodes at 14 sites on 12 neutral and alkaline streams draining historical mining areas in Montana and Idaho. At some sites, concentrations of Cd, Mn, Ni, and Zn increased as much as 119, 306, 167, and 500%,...
Nimick, David A.; Gammons, Christopher H.; Cleasby, Tom; Madison, James P.; Skaar, Don; Brick, Christine M.