CONDITION OF RIVERS AND STREAMS IN THE ST. CROIX RIVER BASIN OF MINNESOTA

Scott Niemela and David Christopherson
Minnesota Pollution Control Agency

The MPCA condition monitoring program described here uses randomly selected sites to assess the condition of rivers and streams in each of the 10 major river basins of Minnesota. The random sampling design allows for the extrapolation of the monitoring results from a small number of sites (approximately 50) to the entire population of rivers and streams in each basin.

This first report focuses on streams in the Minnesota portion of the St. Croix River Basin. Based on an assessment of fish and invertebrate communities, the overall rate of stream impairment was 36%. However, the vast majority of stream impairments (89%) were confined to the southern half of the basin, where developmental pressures from agriculture, urban, and residential development were more prevalent. The same general pattern was observed for numerous water chemistry and habitat variables.

This round of monitoring provided the baseline water quality conditions by which future progress will be measured. Subsequent monitoring rounds will begin to provide the trend information that is critical to measuring the overall effectiveness of our pollution control activities. We also recommend a more intensive monitoring strategy in the impaired watersheds of the southern half of the basin to locate and identify stressors that are influencing stream quality.

Suggested reading

Niemela, Scott, David Christopherson, John Genet, Joel Chirhart, and Michael Feist. 2005. A Comprehensive Assessment of Rivers and Streams in the St. Croix River Basin Using a Random Site-Selection Process. Minnesota Pollution Control Agency.

Niemela, Scott, David Christopherson, John Genet, Joel Chirhart, and Michael Feist. 2004. Condition of Rivers and Streams in the St. Croix River Basin of Minnesota. Minnesota Pollution Control Agency.
http://www.pca.state.mn.us/publications/wq-bsm2-01.pdf