Minnesota has shoreline on only one Great Lake, but it happens to be the greatest: largest, clearest, coldest and, until recently, seemingly least vulnerable to various environmental afflictions elsewhere in the five-lake basin.

The world’s biggest lake by surface area, Superior happens to hold one-tenth of the fresh water on the face of the Earth. Its volume equals those of Michigan, Huron, Erie and Ontario combined, plus several more Eries. Sea kayakers and sailors who travel on Superior like to call it an inland ocean.

There is love in that loose comparison, but also some aptness: Here is a lake that can make its own weather, accommodate ocean-going vessels (and sometimes sinks them), whose resident aquatic species now include emigrants from all over the world thanks to irresponsible handling of ballast water. It’s not only wide but deep; as a newbie kayaker nearly 20 years ago, I was reassured by seasoned companions that the nice thing about paddling Superior is you’re always within a quarter-mile of land – if you count the bottom.

Now the lake and its shoreline communities are experiencing a series of climate impacts that run queasily parallel to the problems of saltwater coasts that have become familiar in recent decades: storms of unusual fierceness and destruction, intensifying rainfall patterns, accelerating coastal erosion and infrastructure losses, overwhelmed wastewater treatment systems, icky (and potentially harmful) algal blooms.

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These changes and more were the focus of a daylong series of expert briefings I attended a while back at Northland College in Ashland, Wisconsin. The sessions were organized for the benefit of the International Joint Commission, a binational treaty organization created more than a century ago to advise U.S. and Canadian governments on transboundary water issues.

This year the IJC has been conducting a “listening tour” in communities across the Great Lakes to gather public comments and concerns about the health of the lakes and the basin, as part of an updating of its own periodic assessment of problems and progress. But Northland’s Peter Annin, a longtime journalist and author of “The Great Lakes Water Wars” who now directs the Mary Griggs Burke Center for Freshwater Innovation, had the idea of supplementing that feedback with something grounded more firmly in scientific and policy expertise. (Full disclosure: He also retained me to help prepare a formal report on the discussions.)

In Annin’s summary for the IJC delegation, Superior’s south shore region — stretching from Ashland and the Apostle Islands westward to Duluth, and eastward to Michigan’s Upper Peninsula — may have entered a “new normal” phase of climate and attendant weather patterns. Some examples presented by the speakers:

Storms: Plenty of Minnesotans well remember the so-called “500-year storm” that struck Duluth in June 2012; fewer may connect the dots between that monster and the “1,000-year” event of July 2016 that was roughly centered on Ashland, followed by another “1,000-year” storm in June 2018 that caused havoc from Ashland to Houghton, Michigan.

Matt Hudson, a Northland faculty member who specializes in watershed restoration, pointed out that the Ashland region has been designated as rainfall “hotspots” by the National Oceanic and Atmospheric Administration – official recognition of current, continuing precipitation patterns far outside historical norms. In Ashland’s case, the volume of rain in heavy storms nowadays is at least 37 percent greater than what was “normal” in the mid-1900s.

Unfortunately, those obsolete rainfall data are the basis of calculations made by engineers and transportation planners when they design roadbeds and determine the size of culverts needed to channel floodwaters underneath them. Also, when they decide how high a bridge needs to be. So when the 2016 storm came to town, blown-out culverts and other damage cut road (and rail) access across the Ashland region; some 8,000 people were able to travel only if heading west. Villages on the Bad River Indian Reservation became islands.

Infrastructure being expensive, Hudson said, planners face difficulty in persuading governments to invested in culvert upgrades based on storm volumes that are still supposed to be once- or twice-in-a-millennium occurrences. And the Federal Emergency Management Agency has rules that allow aid for infrastructure replacement but not enhancement, which encourages continued investment in outdated capacities.

Algal blooms: Until 2012, according to National Park Service ecologist Brenda Lafrancois, the only known instances of algae producing blooms in western Lake Superior consisted of a few small events in the 1960s that were associated with iron entering the lake from mine tailings. It was widely assumed that the lake was simply too cold and too clean — meaning nutrient-poor — for cyanobacteria to form large blue-green masses.

That happy fantasy came to an end a few weeks after the big 2012 storm, when a large bloom formed in the Apostle Islands. It lasted only a couple of days, and was followed by small blooms in 2016 and 2017 that were noticed only by park staff, she said. But in August 2018 the lake grew a five-day bloom that stretched eastward from Superior, Wisconsin, all the way past the Chequamegon Peninsula to Long Island, visible from downtown Ashland.

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Granted, this is not a problem on the scale of the Lake Erie bloom that forced Toledo’s water utility to close the intakes in 2014, or the red tides that are lingering longer off Florida nowadays. But Lafrancois said it appears the blooms are associated with warmer years in general, and are driven in large part by the nutrient- and sediment-laden runoffs that follow unusually heavy rainfalls (which seem to be growing more usual). This is not good news for tourism in a region whose top asset is water so clear, typically, that you can paddle a boat over the shipwrecks off Bayfield and count the vessels’ blackened ribs.

The particular strain of algae in the Apostles incidents is Dolichospermum lemmermannii, known for blooming in colder water (like alpine lakes in Italy) and also for producing a variety of toxins. None of those has been detected at hazardous levels in the Superior blooms as yet, but Lafrancois noted that the samples were few and the list of toxins tested for was short; moreover, for many of the types associated with this strain, no hazard standard has yet been established.

Industrial-scale pollution: Just as Lake Superior and its south shore attract lovers of clean, clear water, there’s also a draw for large-scale mining and agricultural development that poses a threat more serious than algal blooms that briefly paint a shoreline. Two notable recent examples, both abandoned for the time being, are a big iron mine and a huge hog farm.

The Gogebic Taconite project would have dug an open-pit iron mine similar in size to the largest on Minnesota’s Mesabi Range in a wetland-rich area of the Bad River watershed. Northland’s Tom Fitz, a geoscience professor, observed that this poses an unavoidable problem: “You can’t dig a hole in the ground that’s 4.5 miles long and 1,000 feet deep without a big effect on surface water and groundwater”; chief among these would be acid drainage toward the Great Lakes basin’s largest wild-rice beds and, eventually, Lake Superior.

Problem No. 2: Ore in some portions of the mine layout are rich in asbestos-like minerals, and “there has not been a mine anywhere in the world that we know of where asbestiform minerals of this type have been mined and people have not died.” (Think Libby, Montana.)

The Badgerwood pork operation, in the Fish Creek watershed, would have been sized to 26,000 hogs producing 6.8 million gallons of manure annually – in an area whose soils tend to be so heavy in clay content that controlling runoff from family-size farms is a significant challenge.

Jason Fischbach, an ag extension agent with the University of Wisconsin, told the IJC delegation he believes the Iowa company behind the project dropped it because it couldn’t meet standards from the crop fields it needed to feed the hogs. But he also believes similar proposals are inevitable.

Difficult soil and cold weather in this part of Wisconsin long kept farms small and labor-intensive, he explained, and this made for an agriculture sector that was “a little lighter on the landscape” than usual. In dairy, the four counties in the Ashland region had about one-twentieth the number of cows, pastured on five times more acreage per animal, than a comparison area of Wisconsin on Lake Michigan. There was far less row-cropping of small grains, less clearing of woodlands, more retention of pastures planted in deep-rooted, low-maintenance, runoff-reducing perennials.

But low farm income and land values are leading to consolidation across that landscape as people quit farming and neighbors buy their land; Bayfield County, he said, has gone from 100 dairy farms to about 10 in the last three decades. And cheap land is a magnet for outside investors who seek to build Badgerwood-scale operations – essentially the opposite of the region’s traditional farm models.

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Just to be fair and balanced, I’ll close with one of my favorite speakers of the day, Bad River Tribal Chairman Mike Wiggins Jr. Wiggins is widely credited for pursuing litigation that forced Gogebic Taconite to pull back its mine proposal, and he’s currently fighting Enbridge over its Line 5, which crosses his reservation; he is eloquent on the subject of industrial bullying of his people and attempts to grab their land.

But he also spoke for a time in somewhat mystical terms, and possibly playful tones, to challenge his listeners to think of the new rainfall patterns and even the big storm events as positive developments for Lake Superior – and quite literally the reappearance of thunderbirds in Ojibwe lore. Here’s some of what he said, lightly compressed: