2006-04-13 / Front Page

Growing Concern:

Team To Tackle Rampant Weeds in Cedarville Bay
By Amy Polk

A pristine image of the sunrise on Cedarville Bay, from the municipal boat launch, showing the Clark Township municipal docks and Cedarville Marine in the distance, barely disguises the weedy mess residents and visitors say lies beneath the water's surface. In the foreground, a large mat of vegetation can be seen at the surface of the water at the boat launch. A pristine image of the sunrise on Cedarville Bay, from the municipal boat launch, showing the Clark Township municipal docks and Cedarville Marine in the distance, barely disguises the weedy mess residents and visitors say lies beneath the water's surface. In the foreground, a large mat of vegetation can be seen at the surface of the water at the boat launch. Not so long ago, Fourth of July in Clark Township meant log rolls and canoe tipping contests in Cedarville Bay. People sought relief from the hot summer sun by wading into the cool waters of the bay or launching themselves off docks. Anglers pulled yellow perch by the hundreds from the bay.

Today, few would wash their dog in Cedarville Bay, let alone swim in it. Clark Township Hall phones ring in the summer with calls from angry boaters complaining about mats of dead vegetation, green scum on their vessels, and floating garbage, Treasurer Katie Carpenter said during last week's two-day Cedarville Bay Remediation Project meetings.

The April 5 and April 6 meetings, attended by Clark Township officers, Les Cheneaux Watershed Council members, the Department of Environmental Quality (DEQ), staff from University of Michigan and Lake Superior State University, and representatives from three weed control companies, was the first step the community is taking toward cleaning up Cedarville Bay.

As a result of the meetings, Clark Township and the Les Cheneaux Watershed Council will work to harness out-of-control weed growth in the bay, reduce the Clark Township wastewater treatment plant phosphorus discharge many believe promotes weed growth, and improve the appearance of the Cedarville municipal boat launch and public dock.

A town meeting to consider clean-up and control options will be held in late June or early July.

"It's a beginning," said Bob Smith, a member of the Les Cheneaux Watershed Council, who has coordinated much of the research that shows Cedarville Bay is aging prematurely. "The result of this forum is going to be an action plan. When we go away, we want to have an understanding of the weed growth and nutrients from the wastewater treatment plant in Cedarville Bay."

Mr. Smith, a retired microbiologist, returned to his childhood home in Cedarville six years ago and has been working to find an answer to reports that Cedarville Bay is choked by weeds and algae and no longer supports fish. Residents and visitors complain that the water there stinks, and that floating clumps of weeds and trash are bad for tourism. Earlier this year, based on the frequency of citizen complaints, Clark Township made cleaning Cedarville Bay its top priority for 2006.

Mr. Smith has conducted water quality and clarity tests on bays in the area and obtained grants to research Cedarville Bay. His research shows that Clark Township's treated wastewater discharges phosphorus to the bay that is promoting lush plant growth.

Randy Conroy of the Department of Environmental Quality says phosphorous levels are well below state limits.

Mr. Smith agrees, but contends any additional phosphorous is too much for Cedarville Bay.

"The issue is that the state was wrong to permit discharge of such large volumes of nutrient enriched water into a bay that has little, if any, flushing capacity," he said. "Nutrients simply sit in the bay and promote weed growth. The single worst place for the DEQ to permit such discharge volumes between the St. Marys River and Escanaba is Cedarville Bay."

He estimates the amount of phosphorus would fill 300 bags of fertilizer a year. It has been discharged into the bay for 10 years. To illustrate the weed problem, he shows aerial images of propeller cuts through weed mats just under the water's surface.

On the water, boaters complain that their motors sometimes sputter and seize after driving through these dense weed beds, and those familiar with the problem routinely stop after a run through Cedarville Bay to clear their propellers of vegetation.

"It's not a very happy situation for boaters," Mr. Smith said.

Some of the vegetation is healthy, but some of it has been identified as invasive Eurasian water milfoil, an aggressive plant with a tendency to force out native plants. Unlike the native milfoil, Eurasian water milfoil also has a longer growing season than other plants, grows to 10 feet in length, and rapidly creates huge, dense mats that impede recreation and ecological functions. Unchecked growth can lead to a vegetative monoculture in which the single species overtakes the bay, eliminating plants that support native fish, insects, and waterfowl. The milfoil is considered such a big problem around the country that government grants are available for its control and containment. It is easily spread by boats, bait buckets, and anything carrying as small as a one-inch piece of milfoil that will start to grow and eventually root itself in the lake bottom. The plant can live for days without water, so it often is carried from lake to lake on boats and boat trailers. Boaters are encouraged to wash any plants from their boats and trailers when they leave a lake to avoid transporting invasives, and some communities impose stiff fines on boat owners who fail to do so in an effort to control their spread.

In 2003, the Department of Environmental Quality compiled a vegetation profile of Cedarville Bay and found Eurasian water milfoil in several places in the bay, including three large mats on the northeast and southwest sides.

At the time, the DEQ reported that "a lot of plants" were found in the bay, more than 20 species. At the time, the DEQ said the diversity was good, but warned that Eurasian water milfoil threatened those plants.

The forum included presentations by two companies that offer methods to control Eurasian water milfoil. Ray Van Goethem of Aquatic Nuisance Plant Control in West Branch and Martin Hilovsky of EnviroScience Corporation of Stow, Ohio, each made presentations on different control methods available.

Aquatic Nuisance Plant Control offers chemical herbicide applications and EnviroScience offers a weevil application that specifically controls Eurasian water milfoil.

Cedarville Marine on Cedarville Bay is already planning to use a chemical herbicide application this year to control weed growth around the marina. Private citizens and businesses can apply to the DEQ for permits to use herbicide for vegetation control around their property. A permit would have to be obtained to apply herbicide anywhere else in Cedarville Bay. Herbicides are usually dropped around the base of the plants, and are absorbed by the plant to kill it. Mr. Van Goethem said when herbicides are applied, water use restrictions are typically placed on the water body where the treatment is taking place. Water use restrictions may include no swimming, no fish consumption, no drinking, and no irrigation using the treated water. Signs will be posted to warn people of the water use restrictions. Effective immediately, herbicides act quickly and are designed to kill only the plant targeted for removal. According to Mr. Van Goethem's literature on herbicide, health risks are minimized as the chemical dissipates in the lake. Herbicides are used successful to control unwanted plants, but may have to be applied year after year, as needed.

Mr. Van Goethem also described some mechanical strategies for weed control, including barriers to inhibit plant growth, weed rollers, and mechanical harvesting. Harvesting, he warned, does fragment milfoil and may leave many small pieces of the plant to repopulate areas where the plant has been removed.

Mr. Hilovsky introduced the Middfoil method of milfoil removal, which uses a milfoil weevil that burrows through the stalks of the plant, effectively weakening and killing it. Weevils have been effective as early as the first summer they are introduced, and as late as two to three years after introduction.

About the size of a sesame seed, milfoil weevil larvae feed on milfoil all spring and summer, and remain in the water until the fall, when they move into shore and burrow in leaf litter for the winter. The insect will leave the shore in the spring and return to the water. Mr. Hilovsky said the weevils will not enter homes, trees, or move further up from the shore than the first feet of vegetative strip. Milfoil weevils are native in some parts of the United States, and will not eat other plants, he said. They are cultivated in a laboratory in Ohio, and brought into lakes as larvae and eggs on a clump of milfoil that is applied by technicians. Mr. Hilovsky said the insects will eventually propagate and persist as long as milfoil is around. They control milfoil, rather than completely eradicate it, and weevil populations are typically maintained by what little milfoil remains, he said. Weevil populations will fluctuate based on the availability of the food source, he added.

Weevils are being used in more than 85 lakes in 12 states. The nearest weevil project the Cedarville is in Carp Lake, just south of Mackinaw City in the Lower Peninsula. The community planted 13,300 weevils in the 1,900-acre lake, and were able to control the Eurasian water milfoil there in three years, Mr. Hilovsky said. Other weevil projects are taking place in Michigan lakes of Bass, Eagle, Manistee Lake, Pickerel, and Van Ettan, and Lake St. Helen.

The weevils cost approximately $1 to $2 per insect, and several thousand are needed to control milfoil.

Participants also considered a program called CleanFlo, which introduces aeration and beneficial bacteria to water bodies to clean the water and restore healthy plant and animal growth. The presenter of the program was unable to attend last week's meetings, so participants watched an informational program about the method.

All three methods will be discussed again at the public meeting in June or July to determine which course of action the community wants to take. Action will also depend on how much money the community can raise for the project. Mr. Smith suggested there may be some local funding sources, as well. People at the meetings seemed mostly in favor of trying a combination of at least two different methods to determine which is most effective in Cedarville Bay.

"We were able to get our technical information out to others who can help suggest directions we might take to address what we perceive as local environmental issues, and that will be valuable as we take the issues to the community in an organized manner," Mr. Smith said. "We have a better idea of what technology can, or can not, do for us and we can now make more informed decisions on how or if to apply different remediation techniques."

Mr. Conroy of the DEQ said he is open to helping Clark Township find ways to remove more phosphorus from the wastewater effluent.

Clark Township's wastewater treatment facility takes all the raw sewage from Clark Township, and treats the water by aeration and settling to remove waste before it is discharged twice a year as effluent into Pearson Creek. The creek flows into Cedarville Bay. Participants in the meetings suggested additional aeration and a revised settling pond system among methods that might be used to remove additional nutrients from the water before discharge. Mr. Conroy further suggested an earlier discharge time than the spring, when aquatic vegetation begins to grow. Winter discharge may give the phosphorus in the effluent more time to dissipate from the bay before plants begin to absorb it.

Starting this year, Clark Township will add more ferric chloride, a solution first introduced to control odor, to the wastewater to bring phosphorus levels down even more. The solution was found to effectively

remove phosphorus from the water, and Clark Township Board decided a year ago to try adding more.

"Hopefully we'll all continue down this cooperative path, and if we need to get more staff involved, we will," Mr. Conroy said. "I'm amazed by the level of expertise you guys have assembled here."

In addition to the vegetation treatment professionals, Watershed Council members, and Clark Township officials, the meeting also included Doug Pullman, a limnologist from Aquest Corporation, Dave Szlag and Marie Greenwood, both professors at Lake Superior State University in Sault Ste. Marie, and Mike Grant, a University of Michigan scientist who performed many of the first water chemistry assessments of Cedarville Bay.

The meetings were assembled by Mr. Smith and Watershed Council members, who obtained a $950 Les Cheneaux Community Foundation grant. The Foundation awarded the grant because of Cedarville Bay's importance to the community's recreation, tourist, and sport-fishing economy.

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