Water Quality Planning Projects

The majority of the Beaverhead TMDL Planning Area (TPA) is located within Beaverhead County, with a small portion in Madison County and includes the towns of Dillon and Twin Bridges. The Beaverhead TPA encompasses the Beaverhead River watershed, which begins at the outlet of the Clark Canyon Reservoir and flows northeast 79.5 miles before joining the Big Hole River to form the Jefferson River. The TPA coincides with the 10020002 fourth-code hydrologic unit code (HUC), and is bounded by the Pioneer Mountains on the west, the Ruby Range to the east, and the Snowcrest Range and Blacktail Mountains to the south.

Since the conclusion of water quality monitoring projects, three TMDL documents have been published that address multiple streams and pollutant types within the Beaverhead TPA. Nutrient TMDLs, however, are still in development.

DEQ has completed several years of water quality sampling for sediment, temperature, nutrients, and metals in cooperation with the Beaverhead Watershed Committee and others. 

Through this monitoring efforts, the Montana Department of Environmental Quality has identified 15 streams or assessment units with nutrient water quality impairments in the Beaverhead TPA. They are shown in the table below. The TMDL planning process for this TPA incorporates a combination of water quality sampling and hydrologic modeling to further identify and quantify nutrient contributions from all significant sources.

The table identifies which streams have nutrient listed impairments. For complete information on each stream's probable impairment causes and sources, see DEQ's Clean Water Act Information Center.

After a waterbody is listed as impaired for any pollutant, a total maximum daily load (TMDL) is calculated for that waterbody-pollutant combination. TMDLs represent the maximum amount of a pollutant that can enter a waterbody without exceeding the water quality standard. In addition, TMDL documents give specific recommendations for best management practices in order to meet the TMDL value.

Nutrient TMDLs are currently awaiting development based on listings in the 2020 Integrated Report.

Sediment TMDLs were completed in July of 2012. A temperature TMDL was developed for the lower segment of the Beaverhead River in November of 2014. Metals TMDLs were completed in September of 2020. The final documents can be found on DEQ's TMDL page.

DEQ has completed several years of water quality sampling for sediment, temperature, nutrients, and metals in cooperation with the Beaverhead Watershed Committee and others. 

Additional information will be provided as Nutrient TMDLs progress.

The Smith River begins near White Sulphur Springs at the confluence of its north and south forks and flows north approximately 125 miles to its confluence with the Missouri River. The Smith River watershed, shown on the map below with its major tributaries, is surrounded by the Little Belt Mountains to the east and the Big Belt Mountains to the west. The river is popular with recreators due to its trout fishery and canyon scenery, and floaters require a permit from Montana Fish, Wildlife, and Parks.

DEQ was involved in two major projects in the Smith River watershed that concluded in 2024. One investigated the causes of excess algae growth, and the other investigated baseline metals concentrations in the river and selected tributaries. Both final reports are available on this website. DEQ will assess the impairment status of the Smith River using data presented in these reports and all other available and credible data. 

Algae Study

Beginning during the 2015 floating season, recreators reported attached algae growth in the Smith River beyond commonly observed levels. In response to these observations and additional complaints in subsequent years, the Montana Department of Environmental Quality (DEQ) began monitoring algae levels along the Smith River and investigating potential causes of the excess algae growth. DEQ completed the Smith River Algae Study in 2024. DEQ found that Cladophora glomerata (hereafter Cladophora) was the dominant algae species responsible for the excess growth. Cladophora is a native filamentous alga which forms long filamentous streamers which are attached to the stream bed and can, in excess, negatively impact recreators and aquatic life. DEQ found that the likely cause of the changing Cladophora growth is increasing air and water temperatures in the Smith River watershed. Warmer temperatures, aligned with other growth factors, can stimulate faster growth of Cladophora and other algae species especially in the month of June. The study found no increases in nutrient concentrations when compared to the 1970s, and found and no changes to river discharge timing, magnitude, or duration which could have favored excess Cladophora growth.

The specific conclusions of the algae study include:

• Nutrients (nitrogen and phosphorus) are high in June due to normal runoff effects, and now there are also optimal river water temperatures for rapid algae growth occurring at the same time.
• In the Smith River valley, minimum daily air temperatures are trending warmer in spring and early summer, consistent with regional climate change.
• Smith River water temperatures are trending warmer in spring and early summer, driven by warmer air temperatures, and are moving into the ideal temperature range for rapid algae growth by June.

Metals Study

The Smith River watershed has also gained public attention due to the Black Butte Copper Project, an underground copper mine proposed by Tintina Montana, Inc. (Tintina) that would be located 15 miles north of White Sulphur Springs near Sheep Creek, a tributary of the Smith River. The proposed project area is in the south-central portion of the Sheep Creek drainage, approximately 19 miles upstream from the Smith River confluence. Direct impacts to the Smith River are not anticipated from the Black Butte Copper Project, but DEQ recognized the opportunity to simultaneously collect information on major ion and metal concentrations at the same time as the algae study detailed above. Between 2018-2019, DEQ collected water samples throughout the watershed for metals and ions. Water temperatures, flow rates, and other physical parameters were also monitored throughout this period.

Metals are a focus in the Smith River watershed due to diverse geologic conditions along with historical and ongoing land disturbance, primarily from agriculture and mining operations. DEQ completed the Smith River Metals Study in 2024, summarizing baseline ion and metal concentrations in the Smith River and selected tributaries. The report is available on this website and its major conclusions include:

• Data from the past decade show that metals concentrations are generally low throughout the Smith River, with the exception of aluminum and iron periodically not meeting the water quality standards for aquatic life at some locations.
• Some tributaries to the Smith River contribute to changes in metals and chemical characteristics at low concentrations, likely reflecting the natural weathering of geologic formations along with historical and ongoing human disturbance activities within the watershed.
• The metals study report summarizes background conditions prior to any construction or mine development at the Black Butte Copper Project near Sheep Creek, which today has not yet started any mining, water management, or water discharge activities.

After a waterbody is listed as impaired for any pollutant, a total maximum daily load (TMDL) is calculated for that waterbody-pollutant combination. TMDLs represent the maximum amount of a pollutant that can enter a waterbody without exceeding the water quality standard. In addition, TMDL documents give specific recommendations for best management practices in order to meet the TMDL value.

There is not an established timeline for TMDLs on the Smith River, but it is a DEQ priority due to the river’s importance. TMDLs will be completed for any pollutants causing impairment.

In early 2023, Montana Fish, Wildlife, and Parks (FWP) contracted Geum Environmental Consulting and Slough Creek Consulting to:

• Assess historical land use, existing water quality data, and information provided by local individuals and organizations to identify primary limitations to watershed health.
• Identify restoration strategies and priority locations to improve stream and floodplain conditions. 
• Engage stakeholders and work towards facilitating restoration through local organizations.

Key takeaways from the resulting report titled "Smith River Basin-wide Assessment Watershed Restoration Plan" include:

• The main degradational issues within the Smith River watershed are reduced streamflows, floodplain and riparian vegetation loss, increased erosion, increased water temperatures, and pollution from E. coli and nutrients.
• Agricultural land users and recreators play a critical role in implementing best management practices to restore watershed health. 
• This report makes it possible to get grant funding for projects that restore watershed health.