A buoy placed at the entrance to Trinke Lagoon by the Geneva Lake Environmental Agency warns boaters that the starry stonewort invasive species has been found there. (Contributed photo/Regional News)

WILLIAMS BAY — The Geneva Lake Environmental Agency is hoping that warning buoys and herbicides will keep starry stonewort under control in Trinke Lagoon until it can be dredged out of the lake this fall.

But Trinke Lagoon will not be closed to boat traffic.

A state conservation warden says that while waterways can be closed under some circumstances, such action generally comes only during extreme situations, such as flooding.

Rick Reed, a warden supervisor for the state Department of Natural Resources, also expressed doubts about whether closing Trinke Lagoon would be effective in controlling starry stonewort in Geneva Lake.

Starry stonewort is a low-growing plant that stays close to the lake floor, well below boat propellers, Reed said. The plant could be spread if someone drops an anchor into the middle of a plant, pulling up the branches with the seeds still attached and then dropping the anchor elsewhere in the lake.

Reed said that is an unlikely occurrence.

But local conservation advocates are taking steps to control boat traffic in Trinke Lagoon out of concern that they would spread starry stonewort to other areas of the lake.

The Geneva Lake Environmental Agency has posted a buoy just outside the entrance to the lagoon that reads “Starry stonewort control area: Avoid.”

Ted Peters, director of the Williams Bay-based agency, said two additional buoys will be placed in an area where starry stonewort has been found on the east side of Trinke Lagoon. Both buoys will read: “Keep out.”

Peters’ agency had been planning to dredge the lagoon in an effort to remove the invasive plant, but those plans have been delayed until fall by cost overruns.

“Because the dredging won’t take place until the fall, boaters are asked to stay out of Trinke Lagoon to reduce the spread of this invasive,” Peters said.

Starry stonewort was found in Trinke Lagoon last year.

The unwanted intruder, which had not turned up previously anywhere in Walworth County, can grow into thick bushes that disrupt boating, fishing and other recreational opportunities on a lake.

Local and state environmental officials have been working on a strategy to keep the plant from spreading throughout Geneva Lake.

Trinke Lagoon is a harbor that averages about 40 boats belonging to residents of Trinke Estates in the town of Linn. It is also a favorite fishing area for many locals and visitors.

Closing the lagoon “would be almost impossible to manage,” Reed said.

Tim Cavanagh, president of the Trinke Estates Homeowners Associate, said that his homeowners group has worked with the Geneva Lake Environmental Agency and others on the starry stonewort issue, and will continue to cooperate.

Peters said he is urging all boaters and anglers to stay away from the buoys in the lagoon.

Boaters, he said, should check their crafts and accessory equipment for signs of the unwanted plant, he said. They should also clean all plants and bottom mud from their boats and anchors before navigating away from the lagoon, he said.

But limiting access to the lagoon seems off the table, for now.

“All of our laws are based on being able to access public waterways,” Reed said.

It would require an extraordinary situation to have the DNR agree to closing off the lagoon, he said.

He said the DNR would never unilaterally close off an area of a navigable waterway.

The Geneva Lake Environmental Agency previously announced plans to dredge up 2,000 cubic yards of silt from the Trinke Lagoon with the hope of removing starry stonewort.

The dredging was to take place before Memorial Day, before the heavy boat traffic of summer.

But with cost estimates of less than $200,000 for the dredging, only one contractor bid on the job, offering a price of $850,000. The same contractor said it could do the job in the fall for $174,000.

The board of the Geneva Lake Environmental Agency decided to put off dredging until the fall and to take interim steps in the meantime to try controlling the spread of starry stonewort.

In addition to the buoys warning boaters to steer clear, the agency this summer will pay for two chemical applications on the starry stonewort sites. The chemicals are intended to kill the part of the plant that grows above the lake floor.

However, the plant’s buried reproductive organs will likely remain undisturbed, Peters said.

State officials have reported that no conventional eradication efforts have ever been successful with starry stonewort, which was why Peters’ agency wanted to try dredging.

The agency has secured a $380,000 loan and was also recently awarded two state grants of $20,000 each.

According to Peters, the grants will offset the costs of the chemical treatments and education and outreach to boaters.

The agency also has raised about $3,800 in private donations through a Go Fund Me account.

Chris Schultz has been a reporter for more than 40 years. He has been with the Lake Geneva Regional since 2010. He covers the Lake Geneva City Council and the Lake Geneva area schools.