Science · Monitoring

Water Quality Monitoring

Tracking water quality, nutrients, and ecosystem health on the Upper Missouri since 2016.

“We commission independent, science-based studies of river health indicators.”

Ongoing Water Quality Studies

UMOWA has collected water quality data in the main stem since 2016, sampling seven sites between Wolf Creek and Cascade. The Montana DEQ has supported these studies through annual grants, enabling consistent and rigorous monitoring of river conditions.

In 2017, nitrogen and phosphorous levels increased notably compared to 2016. UMOWA intends to expand studies to determine if this represents a trend that could affect the ecological health of the river.

Our Goal

To establish baseline water quality data to assess its influence on benthic macroinvertebrate and plant communities. This data is essential for understanding the relationships between water quality, aquatic vegetation, and the overall health of the river ecosystem.

Long-term trend

Nutrient levels at Craig, 2016–2023

Annual averages of total nitrogen and total phosphorus from UMOWA's monitoring at the Craig site. The jump in 2017 is what prompted UMOWA to expand monitoring — phosphorus peaked across 2017–2019 and has eased since, though levels remain above the 2016 baseline year.

Annual nutrient concentrations (mg/L)

Lower is better. Nitrogen and phosphorus are shown separately because they differ by roughly a factor of ten — the dashed line on each is the old Montana DEQ impairment threshold.

Total Nitrogen

Total Phosphorus

Averaged from the seasonal samples in the appendix raw-data tables of UMOWA's published Water Quality Reports (linked below). Sampling is usually spring, summer, and fall; 2017 has no spring sample (high water) and 2019 has fall only. Annual averages smooth out the autumn spikes that drive most individual exceedances, so single samples in the reports run higher. For full methodology, site-by-site values, and DEQ comparisons, please refer to the PDFs.

Source Reports

Published water quality reports from our monitoring program.

Explore All River Data

Access comprehensive river data, reports, and dashboards from all of our research programs.

View River Data Macroinvertebrate Studies