The algae bloom that smothered much of Lake Erie this past summer was the worst on record, according to the National Oceanic and Atmospheric Administration (NOAA).
That means it was even more severe than the 2011 bloom, which stretched along the shoreline from Toledo to Cleveland, and considerably larger than the 2014 bloom that contaminated the water supply for nearly a half-million people.
The 2015 bloom also was more dense, but fortunately migrated toward deep water. "Fortunately, the bloom moved into the center of the central basin rather than along the shore, resulting in less impact along both coasts," said NOAA's Rick Stumpf.
Fueled by heavy rains, it covered an area of about 300 square miles with a thick, paint-like scum by mid August. But the actual bloom was larger, NOAA said, adding just how big is still being determined.
Rains notwithstanding, the bloom's severity suggests that resource managers haven't been doing enough to minimize runoff pollution.
"It would be hard to find much evidence of progress based on what we saw this year," said Jeff Reutter, former director of the Ohio Sea Grant Program.
On the positive side, Ohio, Michigan and Ontario recently agreed to sharply reduce the amount of phosphorus flowing into western Lake Erie by 40 percent in 10 years. Changes already implemented included limiting when farmers can spread fertilizers and manure on their fields.
With much of that pollution flowing in from the Maumee River in western Ohio, many would like Ohio to pursue a federal impairment designation for the lake. A similar designation for Chesapeake Bay brought in $2.2 billion to help mitigate damage and reduce the amount of algae-feeding nutrients that flow into the bay.