Invasive weed posing problems for Central Canal - 13 WTHR Indianapolis

A very invasive, fast-growing weed is once again causing problems in the Central Canal, the city's primary source of drinking water.

The weed is called Eurasian Milfoil and it spreads like wildfire.

"This is worse than we've see the last couple of years," said Sarah Holsapple, spokesperson for Citizen's Energy.

The weed thrives in hot, dry weather, growing as much as a foot day if conditions are right. That can disrupt flow to the water treatment plant.

"We started cutting in March and we usually don't start until May, so that just shows you how weather impacts the canal," Holsapple said.

She noted they're now running two weed harvesting machines a day, six days a week to cut the weeds back and could soon go to seven days.

While there are chemicals available to kill milfoil, Holsapple said, "We can't treat it with chemicals because it's not safe for the water supply."

Holsapple said it costs up to $350,000 a year to mow the weeds down, money that's built into the budget "so there's no additional cost" to ratepayers.

"We're treating it and you shouldn't notice a difference in the smell or taste of the water," she said. "It's not unsafe. It's just unsightly and an annoyance more than anything."

Pete Patterson, who's been working near the canal, has noticed the weeds and the efforts to keep them at bay.

"I've seen it building up toward the middle and really getting carried away," he said. "It looks better [now that they've cut it] but I just don't know how quick it will come back."

If the hot, dry conditions persists, it's bound to come back very quickly. Holsapple said a change in the weather would help stop the spread.

"If it rains or cools down that stunts the growth," she said.

Given the forecast, milfoil is likely to stick around and so are the weed machines.