Water-Quality Samples

The Montana Department of Transportation (MDT) occasionally causes disturbance to wetlands during construction. To comply with Federal, State, and Tribal regulations, MDT creates replacement wetlands to compensate for wetland loss. The U.S. Geological Survey (USGS) collaborates with MDT to assess potential wetland replacement sites and monitor water conditions at established replacement sites...

The Kootenai River Watershed is an international resource cooperatively managed by the U.S., Canada, and Tribal governments. In recent years, coal mining in the Canadian portion of the watershed has resulted in elevated concentrations of several constituents, including selenium, nitrate, and sulfate downstream (Storb et al., 2023). At increased levels, these mining byproducts can affect water...

USGS studies revealed that aircraft deicing fluids from Jackson Hole Airport negatively affected the water quality of the Snake River aquifer in northwestern Wyoming (Wright, 2013). In response, the airport implemented improved deicing management and infrastructure. A recent USGS study determined that the airport’s changes likely contributed to improvements in aquifer groundwater quality (Wright...

The Wyoming-Montana Water Science Center, in collaboration with the Assiniboine and Sioux Rural Water Supply System (ASRWSS), is monitoring water quality on a seasonal basis at three U.S. Geological Survey streamgages along the Milk River and Missouri River.

Selenium is an essential nutrient with a narrow gap between enough for life and too much for life. Mining operations have been linked to releasing selenium into rivers and streams, where it can accumulate in aquatic ecosystems and disrupt the development of egg-laying organisms like fish and birds. Recent research shows that selenium travels farther from the Elk River Valley than previously...

Water-quality sampling for selenium in the Lake Koocanusa Basin has been occurring since 1972. The USGS WY-MT WSC began a sampling program on the lake in 2018. Water-quality data are collected on the inflows to Lake Koocanusa, in the lake itself, and on the Kootenai River downstream of Libby Dam. All data are available online. Data in graphs are updated monthly to present the latest results. All...

Since 1984, Canadian agencies have collected samples to measure selenium concentrations in the Elk River measured at the monitoring station (site BC08NK0003) (British Columbia Ministry of Forests Lands Natural Resource Operations and Rural Development, 2022) which is 2.2 miles above its discharge into Lake Koocanusa. Detections of selenium from this site have ranged from below detection to greater...

The U.S. Geological Survey (USGS) has collected water-quality samples from selected stream sites upstream from Missoula since 1985.

Wyoming's groundwater and streams are routinely monitored for pesticides. In order to balance the use of pesticides (herbicides, insecticides, and fungicides) with the protection of water resources, the Wyoming Department of Agriculture began a project to sample groundwater in 1995, in cooperation with the U.S. Geological Survey. Since the project's inception, more than 750 samples from...

The Blacks Fork is a stream that contributes a salinity load to the Colorado River Basin. In order to quantify the salinity load, collection of continuous streamflow and specific conductance data, and monthly sampling for total-dissolved solids will occur from April 2018 through September 2019. Calculations of monthly and annual salinity loading from the Blacks Fork were published in 2021.

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.

The Flaxville aquifer is present in the northern and central parts of the Fort Peck Indian Reservation and consists of sand and gravel that forms extensive plateaus and topographic benches used for dryland farming. Because many residents rely on groundwater as their primary water supply on the Reservation, the Flaxville and underlying aquifers are important sources of groundwater. The goal of this...