Battle Creek is a perennial, urban stream located in the western Twin Cities metropolitan area of Minnesota. Historically, the creek was plagued by frequent floods that caused heavy erosion. To address this, the Ramsey-Washington Metro Watershed District initiated a large erosion-control project in the early 1980s. Since project completion, bank erosion and channelization have significantly reduced. However, the population and diversity of fish and macroinvertebrates within the stream’s ecosystem have not similarly improved. In 2014, Battle Creek was added to Minnesota’s impaired waters list for biological impairment of the fish and macroinvertebrate communities.
Working with the district and the Minnesota Pollution Control Agency (MPCA), Barr analyzed water-quality data and fish- and macroinvertebrate-survey information collected over the past 30 years to develop a stressor identification report. Following the U.S. EPA’s Causal Analysis/Diagnosis Decision Information System stressor-identification process, various measures of biological integrity—index of biological integrity, tolerance indicator values, biological metric analytical techniques, etc.—were compared to water quality data to determine which ecological stressors (e.g., turbidity, low dissolved oxygen, heavy metals, etc.) were primarily responsible for biological impairment within the stream ecosystem.
The report was submitted and approved by the MPCA in 2016. Following recommendations in the report, a total maximum daily load (TMDL) for total suspended sediment was developed and completed in 2016. The TMDL report has been submitted to the MPCA and is under final review.