CARDWELL – Volunteers and crews from the Montana Conservation Corps worked through waist deep mud and sediment in the Jefferson Slough near Cardwell last week to remove Eurasian watermilfoil, an invasive aquatic plant that threatens to choke out rivers and streams in portions of the state.
Also known as EWM, the plant grows thick vegetation mats in shallow water that collect sediment. The result is streams and rivers become overgrown with the noxious weed and the ability for water to flow decreases. The weed can infest a variety of aquatic habitats like lakes, ponds, reservoirs and slow-moving streams.
In the Jefferson Slough, the uppermost point on the watershed where EWM has been detected, the species has already taken hold, said project coordinator Celestine Duncan.
The slough is actually fed by Whitetail Creek and Big Pipestone Creek, which Duncan explained is the second highest sediment-producing stream in the state. But as sediment collects in the slow moving water it allows the EWM to take root and spread.
“Once it starts spreading, getting real dense, it traps more and more sediment,” said Duncan.
As the MCC volunteers slogged through the murky backwater, their spirits were high. While reaching into the mud to pull weeds, by hand or using a rake in some areas, might not be the most glamorous summer work, it helped to know they were contributing to an important conservation effort.
“You might think that weed pulling could get monotonous, but its actually been a lot of fun,” said 25-year-old Danny Collom, who was working with a MCC youth crew. “If we can remove it from this area, then we have a really good chance at kind of eliminating its downstream impact.”
EWM can be transported between bodies of water via watercraft and can be caused by people dumping aquariums into a watershed, Duncan explained, emphasizing the importance of cleaning, drying, and inspecting boats and aquatic gear to prevent further invasion. Even plants removed from water and dried completely can will remain viable and continue to spread once returned to an aquatic environment.
Duncan said the sediment layers in the Jefferson Slough are more than four feet deep in some places, reducing the water flow drastically. As 17-year-old Craig Gordon Sim III struggled to keep from sinking down into the muck while pulling weeds with the rest of the MCC youth crew, he understood the concerns presented by the invasive plant.
“What happens is it slows the water flow, allowing more silt to gather up,” said Sim. “As you can see, it kills all of the fish basically. Not even carp can live in it.”
Over the course of the week the group effort removed hundreds of pounds of the plant from the backwater, located approximately five miles upstream from the junction with the main body of the Jefferson. The group was allowed to access the area and camp overnight on the property owned by Tim Mulligan, and concentrated their efforts upstream from a large culvert.
“Our goal is to take everything from these culverts upstream, and we’re going to get rid of every plant we see,” Duncan said of the project. “Start at the top and work down. That’s the only way we’ll get anywhere.”