Water stargrass, a native grass that has reached nuisance levels and some invasive species like milfoil and parrot feather have been choking local waterways.

The Wahkiakum Noxious Weed Control Board was able to secure permitting, and with funds from Wahkiakum County, aquatic treatment was scheduled for Welcome Slough and the Elochoman Slough Marina this year.

This week, a contractor from Ellensburg, Woodland Resource Inc., arrived with their airboat to begin treatment last week.

They are using two chemicals, according to Andy Lea, the coordinator for the Wahkiakum Noxious Weed Control Board, said on Tuesday.

The first is 2, 4-D Amine, which Lea described as a common broadleaf chemical used in lawn herbicide.

“It’s used for dandelion, blackberry, things of that nature,” Lea said.

The second is Diquat dibromide, a contact herbicide for the grass.

“The reason you have two chemicals is that one is for more of the broadleaf, milfoil, type weeds,” Lea said. “The grasses don’t take in the broadleaf chemical, so you have to use something different. The Diquat is a contact that acts normally quickly. The 2, 4-D is systemic and it works its way into the plant, down into the roots, and kills it from the roots. It’s much slower acting.”

They are old established chemicals, Lea added, okayed by the Department of Ecology.

He believes it will be 3-6 weeks before they see results, and it will require maintenance.

“I’m hoping the county will get on some maintenance program for the future,” Lea said.

Signs were posted along the slough and around the marina explaining restrictions, including one day for swimming, one day for pets, three days for drinking, and another restriction regarding irrigation.

Anyone with questions can contact Lea at the Wahkiakum Noxious Weed Board office.