Toxin approved for cleaning Reeds Lake
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The eurasian water milfoil is a tiny plant that causes a big problem, choking out native plants and animals.
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By Elisabeth Bont
Community News Editor
Concerned Reeds Lake may soon be unusable by people and animals alike, the East Grand Rapis City Commission voted last week to spend $46,000 on an herbicide designed to combat a recent explosion of exotic weed growth.
The unanimous vote, supported enthusiastically by area residents and reluctantly by area environmental groups, approved the use of the technically toxic chemical, Sonar, against Eurasian watermilfoil, an aquatic weed that has begun to crowd both native lake species and area residents out of Reeds Lake.
“It’s very bad,” said Bill Barrager, Director of City Services for East Grand Rapids. “It is so bad that it’s tough to get boats in and out of the water.”
“We have times when areas of the lake are pretty much impassable due to weeds,” agreed Chris Schneiter, director of the Grand Rapids Yacht Club. “We have to stay on top of it somehow.”
According to a report by Michigan Lake and Stream Association, Eurasian watermilfoil, which was brought to the United States as an aquarium plant and has since spread to lakes in 37 states, clogs waterways by “forming thick mats at the water’s surface.”
The weed “can out-compete against other existing, native plants, because it doesn’t have a lot of natural predators,” said Tom Carey, director of the West Michigan Environmental Action Council.
“If it continues to grow without management, it can affect the whole ecosystem,” changing fish populations and decreasing species diversity.
In the past, Professional Lake Management attempted to solve the milfoil problem by using harvesting machines to cut vegetation out of the lake, said Jason Brokestra, Vice President of PLM, which is working with EGR to keep Reeds Lake’s environment stable.
Unfortunately, because loose pieces of cut milfoil can float to other areas of the lake and quickly take root, “the more you cut, the worse it gets,” said Barrager.
Milfoil weevils are another possible solution, said Carey, but they have only a 50% success rate and cost nearly a dollar each, making them less predictable and nearly as expensive as Sonar and other herbicides.
Sonar, which has been used recently on area lakes such as Lake Bella Vista and Silver Lake, is the safest herbicide available, said Broekstra, because it kills milfoil but leaves other plants and animals relatively unaffected.
“Different organisms respond to different chemicals in different ways,” agreed Carey, citing a recent report from the U.S. Army Corps of Engineers that “supports the idea that the application of Sonar at 5-8 parts per billion does not seem to have a dramatic effect” on species other than milfoil.
Sonar “affects the pigments of the plant,” breaking down yellow pigments and exposing green pigments to lethal amounts of sunlight, said Brokestra.
Professional Lake Management plans to use a concentration of 6ppb in Reeds Lake this spring, he said.
PLM estimates Sonar application will cost the City of East Grand Rapids nearly $40,000 the first year and $10,000-20,000 in spot treatments over the next few years.
According to Carey, Sonar concentrations must stay at 5-8ppb for 60 days for the treatment to be affective. This number worries members of Michigan’s Department of Natural Resources, he said, because some fear equal distribution of the chemical will be impossible, creating over-concentrations in some areas of the lake and under-concentrations in others. Since milfoil is potent at a mere 5 ppb, overdoses could negatively effect other lake species.
Carey stressed the need to act quickly, however. He argued that the longer EGR waits, the more dead milfoil will be left after Sonar application, increasing the risk of eutrophication, a lake-wide oxygen loss caused by bacteria overpopulation.
Barrager and the EGR city council hope the Sonar application will eradicate milfoil “well enough to let the native plants come back” and take back the lake. “We don’t think we’ll have to use Sonar and treat the whole lake again for 6 to 8 years,” he said.
Carey admits he is wary of using chemicals to solve a natural problem, especially since Sonar was only approved by the Michigan Department of Environmental Quality two years ago and has not been tested extensively. “We need to know more about it,” he said. “Unfortunately, there hasn’t been a lot of good research.”
Nevertheless, Carey and other environmental groups acknowledge something must be done to prevent milfoil from destroying the Reeds Lake ecosystem. “I don’t think its an ideal solution,” he said, “but I think it’s a feasible solution.”
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