In 2010 and again in 2015, the MPCA collaborated with the U.S EPA in a national river and stream probabilistic (random) survey. These projects help to determine past and current water conditions and trends across the state. For this project, 150 sites were selected randomly and proportionally across Minnesota’s three ecoregions. In 2010, station locations were newly established and sampled, whereas in 2015, 50% of the stations were newly established and 50% were pre-existing stations from the 2010 project. The pre-existing stations were used for trend analysis. Stations were sampled for biological communities of both fish and macroinvertebrates (bugs). Water chemistry samples were also collected, and analyzed for various pollutants.
The reports with the results of these surveys:
- Conditions of rivers and streams in the St. Croix River Basin of Minnesota
- The Condition of Rivers and Streams in Minnesota, Based on Probabilistic Surveys, 1995-2011
The MPCA expects to again take part in this national survey in 2020.