Eagle Bend treats aquatic invasive species

In May Eagle Bend took the first step toward eradicating curleyleaf pondweed from its channel and harbor by treating them with herbicide.

The next step is to come up with a plan for treatment of Flathead Lake, Flathead River and Fennon Slough. Erik Hanson of the Aquatic Invasive Species working group is crossing his fingers that treatment can start before the end of the summer.

“The main thing now is finding the funding to do the rest of the work and deciding who’s going to do it,” Hanson said.

Because the harbor and channel are considered private land, private entities were able to spearhead the effort to get curleyleaf treated within those areas.

Flathead County commissioner Pam Holmquist said she supported Eagle Bend’s decision to go ahead with weed treatment because it was the right thing to do.

“We were all very concerned about that,” Holmquist said. “It’s a great step forward.”

Treatment in the other waterways affected by the aquatic invasive species has to wait until the county comes up with a new version of their invasive weed management plan. The current plan doesn’t include any details on how to deal with aquatic invasive species.

At Monday’s Flathead County weed and parks board meeting, the board said they sent a version of the revised weed management plan to county commissioners and county attorneys. The weed board is hoping to nail down a final update that includes treatment of aquatic invasive species during their July meeting.

Hanson worked with the Eagle Bend Yacht Harbor Boat-Slip Owners Association, the Flathead Basin Commission and the Montana Department of Environmental Quality to perform herbicide treatment in the harbor and channel on May 15 and 16.

Hanson said they used Diquat, a herbicide that “targets anything green,” has undergone 30 years of testing and is approved by the DEQ, to treat the pondweed.

“These herbicides are extremely safe,” Hanson said. “There are virtually no toxicity concerns to aquatic life.”

The goal was to get the herbicide in the water before spring run-off caused the water levels to rise too high. Before treating the channel, a curtain was strung across the entrance between the channel and the river to prevent the herbicide from leeching into the river.

The aquatic weed consists of a thin stem with blue-green leaves attached in an alternating pattern. Turions, a hard pinecone-like bud that falls off the plant, form in the spring. They are carried by water currents to new locations in late summer. Wherever they land, they can start a new plant. Turions’ germination rate is 60-80 percent.

It’s early enough in the aquatic plant growing season that curleyleaf can be specifically targeted because it is the first plant to grow. At first glance, Hanson said the treatment appears to be successful.

“I think we need to congratulate Eagle Bend on their proactive protection of Flathead Lake and Flathead River from this noxious weed,” Hanson said. “They stepped up.”

Eagle Bend put up $10,000 and gave the okay to go ahead with the treatment in April. The Eagle Bend owners association deferred all comment on the matter to Hanson and Caryn Miske.

“We felt pretty strongly that now is the time to treat it,” Miske said.

Miske of the Flathead Basin Commission has worked with Hanson, Eagle Bend and several government agencies to get some kind of a working plan put into action since the invasive weed was discovered last year.

Hanson identified the aquatic invasive species and performed a survey of the area last August. Curleyleaf pondweed had heavily infested (40 percent of the plants) Eagle Bend’s harbor and channel.

It was also found in patches along the Flathead River bottom leading upstream for a couple of miles, in Fennon Slough and in two places in Flathead Lake — just outside of the harbor in Somers and along a seawall outside of Bigfork.

Because Diquat targets plants that are already alive, the turions already in the soil of the channel and harbor will most likely start to grow in the late summer and Eagle Bend’s waterways will need to be treated again.

Miske said the group is planning on monitoring the progress once a week throughout the rest of the summer and it will take treatment every year for the next 3-4 years to eradicate the weed completely.

The next Flathead Basin Commission Meeting will be on Wednesday, June 13, from 10 a.m. to 2 p.m. at the U.S. Forest Service office at 650 Wolfpack Way in Kalispell.

The county’s new weed plan, the upcoming legislative meeting and the status of the boat inspection stations are on the agenda to be discussed.

An update will also be given on Eagle Bend’s progress. For more information about the meeting contact the FBC at 240-3453.