13 WTHR - Indianapolis News |Water company fights weed invasion

Water company fights weed invasion

Mary Milz/Eyewitness News

Marion County - A monster weed is growing in Indianapolis' Central Canal and there's no way to kill this fast-growing plant. That's a big concern for the Indianapolis Water Company because the canal is the primary source of drinking water for the city.

"It's very aggressive and very invasive, and the more aggressive it is the worse of a problem it creates," said Jo Lynn Garing, Water Company spokesperson. 

At issue is a combination of weeds - curly leaf pond weed and even worse, Eurasian milfoil. It's a dense exotic plant non-native to Indiana that somehow got in the canal and grows like wildfire, as much as eight to ten inches a day in the heat of summer.

"The weeds, they impact how much water we can get into the water treatment plant, so we're trying to get out as many weeds as possible so we can improve the flow of water to the plant," said Garing.

She said crews using weed harvester machines have been on the canal 12-14 hours a day, every day since June. And the more they cut, the faster the weeds grow. That's because even though they haul away the clippings, the smallest piece that floats away can sink to the bottom and produce more plants.

"It's been more of an issue this year due to the hot dry weather. The water temperature in the canal is a lot warmer than usual," said Garing. 

She said using chemicals is out of question because of concerns about the water supply. She said other options are weed-eating insects or fish, but like the weeds, they too could also multiply, creating other problems.

She said the water company should get a reprieve in the next few weeks. The weeds stop growing when the water temperature drops to the low 60's. In the meantime, the weeds aren't the only things piling up. So are the costs, said to be thousands of dollars each day.

Eurasian milfoil was first noticed in the Central Canal about five years ago. It's also in the White River and Geist Reservoir. It's readily spread by boaters, trailers and even bait buckets, and if kept moist can live for up to two weeks. That's why the water company must follow DNR rules for disposal, which include taking the clippings to a separate site where they're left to decompose.