'Too much of a good thing:' How excessive fall leaves can cause summer algae

SOUTH BEND, Ind. -- The battle between fall leaves and fresh lawns has begun across michiana. No matter what tools it takes to tame the tree leaves, the city of South Bend will soon swoop in with some additional help.

Jitin Kain is the deputy director for South Bend Public Works. "We will have crews going throughout the city, area by area," Kain said.

Kain said the city’s leaf collection program will return in early November, offering two rounds of re-leaf throughout the season.

"We want the leaves to be in the tree lawn area and not the street. If they're in the street, then they can clog up catch basins and storm drains," Kain added.

If too many leaves make it down the drain, they can create a danger to local bodies of water.       Nate Bosch is the director of the Lilly Center for Lakes and Streams at Grace College.

"Fall leaves are a good thing for our streams, as they're an energy and a nutrient source, but it can be too much of a good thing, bosch explained."

bosch said autumn is typically a time for aquatic insects to feast on fall foliage. But michiana’s tree canopy provides a buffet that bugs can’t handle.

"We have so many leaves that come into our streams, and then we have so many nutrients as those leaves decompose and get broken up, that we start to get problems downstream in those rivers or lakes," bosch said.

An overabundance of autumn leaves can lead to weeds and algae blooms in local lakes, and while some algae growth is possible in the fall and even the winter months, algae from leaves can actually re-emerge during the following summer.

"As those leaves continue to decompose over the winter, maybe even into the next spring and summer, those leaves are going to be giving off nutrients," bosch described. "And then they could potentially be causing recreational problems or ecological impacts from something that happened many months ago."

bosch said while we can’t stop leaves from landing in our lakes and streams, we can do our part to not make the situation worse.

"We don't want people to purposefully put their leaves into local streams or rivers," bosch said. "We also don't want to see people put leaves into the gutters along the streets or into driveways, and that usually goes directly out to a stream or a lake as well."

For a map and schedule of all South Bend leaf collection zones, click here.