Some worry that herbicides will harm fish and other animals. But others say the tangles of milfoil are dangerous to swimmers.
Milfoil treated in response to growing problem
Some say treating weeds in Patterson Lake with an herbicide will harm fish and wildlife. But others contend that milfoil poses a danger to swimmers and animals, who can become entangled in the dense weeds and drown.
After dealing with a worsening milfoil problem for years, Sun Mountain Lodge and the Wolf Creek Reclamation District have contracted with a weed-spraying company to treat a hybrid milfoil that has taken over most of the shoreline. The spraying will occur this weekend, Oct. 12 and 13.
“Hybrid milfoil is pretty darn aggressive,” Anna Lyon, manager of the Okanogan County Noxious Weed Office, said. “The treatment is a safety issue, not just for aesthetics.”
Milfoil poses a hazard to swimmers because they can get caught up in the weeds, Lyon said. “If my grandkid was out there swimming, I’d be yanking them out of the water because of milfoil,” she said.
Mike Kutz watches geese, ducks and beavers while he hand-pulls the milfoil in front of the 1/3-acre piece of Patterson Lake shoreline he owns. “Any herbicide is totally unacceptable in my world,” Kutz said.
Kutz recognizes that swimming through weeds can be unpleasant, but he’s more concerned about the effects of herbicides on the environment. “Everyone freaks out when stuff gets wrapped around their feet when swimming,” he said.
Kutz has recreated on the lake for decades. Since he and a dozen other people bought the lot eight years ago — where they put up a small building they call a “yacht club” — he’s seen milfoil multiply.
“Ninety percent of the lake has milfoil. There’s no getting rid of it — that stuff is tenacious. You just pull it, like any other weed,” Kutz said. He uses the milfoil he pulls as fertilizer.
Three or four years ago, milfoil started to become a significant problem for Sun Mountain, lodge general manager Brian Charlton said. The weeds were so thick near the boat dock that guests would complain, and it became dangerous for swimming. “They were quite rightly upset and concerned that they’ll get tangled in this stuff when they get back to land,” he said.
Sun Mountain gets its drinking water from the lake, and about three years ago lodge employees began noticing a “nasty discoloration” and a bad aroma. Sometimes the lodge had to buy bottled water for the guest rooms, Charlton said. They even dumped thousands of gallons of water until it ran clear.
Sun Mountain’s drinking water is tested weekly by Okanogan County. The tests attributed the problems primarily to algae and manganese, Charlton said.
Sun Mountain’s drinking water is taken from the middle of the lake and treated by sand filtration and chlorine. When herbicides are used, they test before, during and after the application, as well as from various faucets at the lodge, Charlton said.
“I’m like everyone else. You don’t want to dump a bunch of chemicals in and kill everything off. We’ve been extremely careful,” Charlton said. “My wife and I are beekeepers.”
Sun Mountain has hired a contractor to do minimal spraying to control weeds and clean the intakes the past few years. The problem has improved — this year was the first in a while when they didn’t have major problems, Charlton said. Sun Mountain is hoping to come up with a long-term treatment to keep the milfoil from growing back, Charlton said.
Sun Mountain owns most of the land around the lake, and the reclamation district owns most of the perimeter, according to Charlton.
Spraying from boats
Kyle Steelhammer, owner of Northwest Aquatic Management, in Rochester, Washington, will be applying the herbicide within 50 to 60 feet of the shoreline, in shallow areas where the milfoil grows. They’ll broadcast the herbicide with a handgun from boats, with some subsurface application, he said.
“Sun Mountain got tired of occupants who can’t use the waterfront,” Steelhammer said.
The planned weed spraying caught the attention of some commenters on the Methownet bulletin board. “The many creatures who live in the lake don’t deserve getting hurt/poisoned because they want the lake to appeal more for tourism,” Loren Boley (Kutz’s stepson) said. He suggested people just navigate around the weeds when they swim.
But others said the treatments are necessary. “I for one, do not want to lose the use of the lake for boating and swimming because of the Milfoil, that was undoubtedly introduced by an errant boater, and the Ecology permit process takes into consideration, all of the use factors before a permit is issued,” Rick Karro said.
“The mill foil [sic] will choke out the lake and eventually take over the lake and eventually make it non usable…. I would thank them for keeping the lake clean,” said another.
There are other, nonchemical approaches to controlling weeds, like using a submarine with shears to comb the bottom of the lake. “It sounds far-fetched, but if you have enough money and time…,” Charlton said.
Steelhammer talked with Kutz and agreed not to spray his property. “I have no problem with Kyle,” Kutz said, although he plans to be at the lake this weekend to watch and protect his lakefront.
Milfoil a longtime problem
Milfoil has been a problem in the Okanogan County for about 10 years, Anna Lyon, manager of the Okanogan County Noxious Weed Office, said. Initially the county thought it could draw down a lake so milfoil would freeze and die over winter, but it didn’t work.
Milfoil is also a danger to animals. Lyon said two deer died after getting trapped in milfoil in Conconully and Spectacle lakes in northern Okanogan County. Because it takes up oxygen from water overnight, milfoil can kill fish by asphyxiation, Lyon said.
Hybrid milfoil occurs when a native milfoil hybridizes with Eurasian milfoil. It’s often not a problem, Lyon said. “But at other times, it’s like your worst nightmare, like milfoil on steroids,” she said. The weed office usually doesn’t treat native milfoil, which typically cycles in and out over the years, Lyon said.
A survey done in 2014 found about 25 acres of 160-acre Patterson Lake was contaminated with milfoil, Lyon said. By contrast, there was less than 1/10 acre of milfoil on Pearrygin Lake.
The Washington Department of Ecology issues five-year permits for aquatic-weed control. Okanogan County added Patterson Lake to its permit several years ago. The initial permit and periodic renewals require a legal notice and public comment. Once a water body is added, there is no requirement for annual notification to the general public, according to Jon Jennings, aquatic pesticide permit specialist for Ecology.
Property owners within 1/4 mile of any area that will be treated must be notified 10 to 42 days in advance. The applicators are required to post the shoreline with the dates of treatment and any restrictions for water use right before the herbicide application, Jennings said.
Okanogan County has received Ecology grants for aquatic weed control over the past several years, but the Patterson Lake treatment — estimated at $7,300 by the contractor — will be paid by Sun Mountain Lodge and the Wolf Creek Reclamation District, Lyon said. The county hopes to obtain some grant money to help offset the cost, she said.
Flumioxazin: ‘Relatively nontoxic’
Northwest Aquatic Management will use an herbicide called flumioxazin (brand name Flumigard).
In the environmental impact statement (EIS) done for herbicides for freshwater aquatic plant management, the state Department of Ecology found flumioxazin is less toxic than the other two contact aquatic herbicides used in Washington. “There are few effective and less toxic algaecides available to Washingtonians,” they said.
Flumioxazin is fast-acting. It is considered “relatively nontoxic” to mallard ducks and “moderately toxic” to rainbow trout. Patterson Lake is home to rainbow trout, bass and kokanee, according to the Washington Department of Fish and Wildlife.
Although considered to have low to medium toxicity to fish, these herbicides can cause plants to decompose rapidly, which can lead to a loss of oxygen in the water. That oxygen depletion may cause fish kills, according to the EIS.
The U.S. Environmental Protection Agency (EPA) concluded flumioxazin is short-lived and that its potential to contaminate the environment is relatively low. EPA classified flumioxazin as a “not likely” human carcinogen.
Although contact herbicides like flumioxazin tend to be more acutely toxic to aquatic organisms than other herbicides, they break down sooner and are therefore generally less harmful in the long run, according to the EIS.
There are no label restrictions for using treated water for drinking, swimming or fishing after applying flumioxazin. There is a waiting period before using water for irrigation, but the irrigation intake from the lake has already been shut down for the season.
