A big threat to the Great Lakes comes from outdated sewer systems that can carry bacteria into waterways, and lead to closed beaches and drinking water warnings. Now, some cities are fighting back – with trees.
In nearly 200 communities, sewer systems handle both stormwater and sewage. When it rains a lot, these systems get overloaded, and untreated water -- or sewage -- runs into the Great Lakes or nearby streams and rivers.
“These outflows happen up to 82 times per year at some spots in Cleveland,” says U.S. Forest Service scientist Michelle Kondo.