EVALUATING WATER QUALITY IN CHEQUAMEGON BAY, LAKE SUPERIOR, RELATIVE TO OTHER GREAT LAKES EMBAYMENTS

The intent of this study is to work towards determining how water quality conditions in Chequamegon Bay compare to other Great Lakes embayments and nearshore areas currently experiencing water quality issues such as cyanobacteria blooms. Basic water quality parameters such as Chlorophyll-a and Total Phosphorous were collected from Chequamegon Bay from 2014-2020 by the Mary Griggs Burke Center for Freshwater Innovation and compared to data from the EPA STORET database for 5 embayments around the Great Lakes, as well as data for Green Bay from NEW Water to determine the comparative health of Chequamegon Bay.

Analyses will evaluate mean concentrations of Chlorophyll-a and Total Phosphorous as well as annual and long-term trends throughout the study sites. Direct comparisons of the morphology, size, shape, depth and watershed land cover of the study sites will assist in overall comparisons. These evaluations will be used to investigate and describe any patterns among great lakes embayments experiencing water quality issues that could inform our understanding of the risk of similar water quality issues in Chequamegon Bay.

Total Phosphorous and Chlorophyll-a concentrations provide a good estimate of the overall health of a water body and whether it is suffering from nutrient pollution and eutrophication, factors that lead to many water quality issues including blue green algae blooms. Although Lake Superior is the largest and coldest of the Great Lakes, it too has begun to exhibit seasonal blue green algae blooms documented primarily along its Wisconsin shoreline near Chequamegon Bay. The bay has yet to experience any documented blue green algal blooms or other issues related to nutrient pollution, but the clay soils and history of the watershed as well as rapid regional climate change and relatively shallow water make it particularly vulnerable to future issues. This study is expected to be able to draw direct comparisons between Chequamegon Bay and other Great Lakes embayments to assess the potential risk of water quality issues.

Although many areas around the Great Lakes are increasingly experiencing severe water quality issues, such as blue green algae blooms, Chequamegon Bay has yet to experience these issues, making it an important resource to understand and protect especially considering the regional vulnerability.