WILLIAMS BAY — Plans to dredge a Geneva Lake lagoon to try removing an invasive plant species are being shelved for several months because of higher-than-expected costs.

The project was expected to cost about $160,000, but a solicitation drew only one contractor proposal, and the contractor wanted $850,000.

The Geneva Lake Environmental Agency has postponed the dredging effort until fall, when officials hope to find lower costs.

Officials had planned to dredge the lagoon this spring in hopes of removing starry stonewort, an unwanted plant-like algae that could spread throughout the lake and disrupt recreational activities.

As interim measures, officials now hope to combat the starry stonewort with chemicals, and to discourage boaters from using the lagoon, which is located near the Trinke Estates neighborhood in the town of Linn.

The unexpectedly high costs came just as the Geneva Lake Environmental Agency had succeeded in finding a place where the dredged material could be stored this spring while it drained dry.

Ted Peters, director of the Williams Bay-based agency, said he was disappointed to see the $850,000 bid from Integrated Lakes Management Inc. of Waukegan, Illinois. Peters said he hopes to seek new contractor proposals soon, with an eye toward dredging the lagoon in the fall.

“We worked so hard to be where we’re at, and I don’t want to lose it,” he said.

Peters reported the setback April 18 to his agency’s board of directors.

Integrated Lakes Management’s reported that it could do the job in the summer for $189,000 or in the fall for $174,000.

Keith Gray, owner of the contracting firm, said his company’s work schedule is already booked for the spring dredging season.

Gray said he wanted to help the Lake Geneva effort, but doing it this spring, he said, would be difficult and expensive.

“I can no longer use my own equipment, because it’s committed to somewhere else,” he said. “I have to rent equipment, and I have to find labor I don’t have.”

Peters suggested that the project be rebid for a fall dredging in an attempt to get bids from other companies.

The agency board of directors voted unanimously to rebid.

Starry stonewort is a plant-like algae that spreads quickly and grows into thick mats that crowd out native plant and animal species, and also disrupts boating, fishing and other lake recreation.

No known eradication method has worked, so dredging the Trinke Lagoon is seen as a good option for uprooting and removing the unwanted plant before it spreads to other areas of Geneva Lake.

Officials had expressed a sense of urgency to get the dredging done before boating season this summer.

Peters, however, said waiting until fall has its advantages, too.

It relieves a time crunch.

The Geneva Lake Environmental Agency still has to secure a loan from Town Bank to pay the dredging contractor. If dredging were moving forward this spring, the loan would have been needed by May 3.

“It was getting so tight, I was getting uncomfortable,” Peters said.

During the fall, boat traffic in the lagoon will be reduced.

The fall dredging would proceed as it would have in spring, with 2,000 cubic yards of lake sediment from the lake’s bottom removed, with the dredged soil deposited temporarily along the shore to drain dry.

Officials had struggled to find a suitable place for the sludge to drain — a process that could take a couple of months — but that issue seemed resolved just before the costs became an issue.

The Linn Town Board agreed April 8 to give the agency permission to put the sludge on an abandoned roadway called Golf Road, which is owned by the town. The site is southwest of the Trinke Estates neighborhood.

If the dredging is done in the fall, the sludge would be left onsite to drain over the winter. And the sludge then would be moved to a landfill for disposal.

The disadvantage of shelving the dredging effort for several months is that the delay gives the starry stonewort a better chance of spreading into the lake.

As interim measures, the environmental agency has posted a buoy near the entrance to the lagoon with a warning to discourage boaters: “Starry stonewort control area: Avoid.” More such buoys are planned inside the lagoon.

Officials have discussed trying to close the lagoon to boat traffic, but state officials will not allow it, considering that all of Geneva Lake is a public waterway.

Peters said that moving back the dredging date means the agency will also have to reapply for two $20,000 lake protection grants through the state Department of Natural Resources. The grants are reimbursement grants, meaning the agency would receive them for money spent up front for the dredging.

In addition, the agency’s member communities need to sign an agreement that commits them to backing the agency’s request for a $300,000 bank loan. The agreement would commit the communities to repay the loan if the agency is unable to pay.

Member communities are Lake Geneva, Fontana, Williams Bay and the town of Linn.

Fontana Village President Pat Kenny said his village board already has committed to supporting the project to eradicate starry stonewort.

Lake Geneva Alderman Doug Skates said he believes Lake Geneva, too, would be willing to back the loan.

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.