ASHLAND, Wisc.- Lake Superior, long considered to be the cleanest of the Great Lakes, is showing new signs of vulnerability, according to a white paper released today by the Northland College Mary Griggs Burke Center for Freshwater Innovation.
Experts point to increased intensity of storms — likely associated with climate change — historic land use practices, and erodible soils specific to the south shore of Lake Superior as the reasons behind increased sedimentation rates, escalated infrastructure damage, and the first-recorded widespread blue-green algal blooms in the lake.
“We weren’t even thinking about super storms and algal blooms in Lake Superior until a few years ago,” said Matt Hudson, associate director of the Burke Center. “Since 2012, we’ve been served a new reality and a new set of challenges.”
The white paper is the result of a daylong summit at Northland College in September to discuss water quality concerns with the International Joint Commission, a bi-national organization charged with assessing water quality goals set out in the 1972 Great Lakes Water Quality Agreement.
The Burke Center convened a mix of experts from city and tribal governments, state and federal agencies and academia, to examine what is believed to be a “new normal” in water quality issues along the south shore of Lake Superior.
The region, spreading from Duluth, Minn., to Houghton, Mich., experienced 500-hundred-to-1,000-year storms in 2012, 2016 and 2018, resulting in flooding, blown out bridges and culverts, sewer system overflows, agricultural runoff and more than $150 million in damages.
“This new normal of extreme weather events is something we’re just starting to understand,” said Valerie Damstra, operations manager with the Burke Center.
The most noteworthy development in this storm-driven “new normal” is the appearance of potentially toxic blue-green algal blooms.
Brenda Lafrancois, an aquatic ecologist for the Midwest Region of the National Park Service, reported that until 2012, the only reports of algal blooms in western Lake Superior were few and anecdotal.
The 2012 bloom spread along parts of the south shore of Lake Superior in Wisconsin during warm July weather, weeks after the 500-year-storm in Duluth. Then in 2018, following the 1,000-year-storm near Ashland, Wis., the bloom stretched roughly 80 miles from Duluth to areas near Ashland.
The white paper concludes that the algal blooms, along with other storm-related water quality issues, will require more than a tweak of the 1972 Water Quality Agreement.
“We need to adapt and reassess the tools we have and use to protect water quality, not just in Lake Superior, but the whole Great Lakes system,” Hudson said.
For more information: northland.edu/watersummit