PONDWEED, YOUR TIME IS UP. The City of Eau Claire is tackling Half Moon Lake's pondweed problem – pondweed is an invasive species – by reallocating funds to create a new forestry position that will use an aquatic weed harvesting machine to clear the lake.

Half Moon Lake (615 Randall St., Eau Claire) is a well-known recreation spot in the Chippewa Valley. For decades, the lake’s sandy beaches and ample fishing spots have drawn college students and residents of all ages in the summertime. In recent years, however, an infestation of the invasive curly leaf pondweed has altered the local spot for the worse.

To offset the spread of pondweed, the City of Eau Claire has continued to allocate $100,000 annually to chemically treat the lake with a substance called endothall. Now, per updated DNR recommendations, local government officials voted to eliminate the chemicals altogether and switch to a fully manual method of clearing.

This decision was made as part of the Eau Claire City Council’s routine Capital Improvement Plan (CIP), which was passed unanimously by council members at their June 24 meeting. The environmental portion of the plan was penned by council members Jessica Schoen (District 1) and Andrew Werthmann (District 5).

“We've made tremendous progress over the years and we want to keep the lake in good shape.”

LANE BERG

EAU CLAIRE Community Services Director

The City of Eau Claire has been chemically treating the pondweed, pictured above, but it has not proven to be a long-term solution.

Using the $100,000 previously allotted for endothall, Schoen and Werthmann opened up the potential for a new forestry position that would spend the summer months manually clearing the lake, using an aquatic weed harvesting machine. Werthmann explained that $75,000 of that funding will be put toward the new salary and current employee hours, while the remaining $25,000 will be put toward a biodiversity matching fund.

“Community members can either bring their volunteer hours and have them matched to that (biodiversity) fund, or they can raise money for a project and get an equal match from this fund,” Werthmann said. “That could be (put) toward a new community garden; that could be tree planting, rain gardens, creating a prairie — it could even be a removal of invasive species like buckthorn or garlic mustard.”

Schoen, who has an academic and professional background in environmental efforts, said the endothall treatment has been on her mind gaining a seat at the dais.

“Over time, we've learned that (endothall) is not a very effective treatment. It's not a very long-term solution to manage that invasive species,” Schoen explained. “This year, they thought they'd finally eradicated the pondweed, but when they didn't treat for the species, it came back really aggressively again. So again, the endothall just isn't effective for its intended purpose.”

Lane Berg, community services director of the City of Eau Claire, said the city is currently performing some manual removal of the pondweed in addition to the endothall. However, the aquatic weed harvesting equipment his department has on hand has not been updated since the early 1990s.

Due to the age, width, and pace of the machine, he remarked, the clearing process is rather tedious. “It’s definitely served us well, but it only cuts the 6-foot wide path, and it's extremely slow. It travels at about half a mile per hour when it's cutting weeds,” Berg said.

For this reason, the city is hoping to purchase a new aquatic weed harvester before transitioning to complete manual removal next summer. Berg mentioned the possibility of a DNR matching grant, which would slash the cost of a new machine — roughly $300,000 — in half.

According to Berg, the harvested pond weed does not go to waste. City employees repurpose the vegetation as compost, which is available for sale at their brush site (5710 Jeffers Rd., Eau Claire). Compost is $1 per five-gallon bucket, with residents asked to bring their own buckets during pickup.

Despite the city's efforts to eradicate the pondweed by use of endothall, the invasive plant returned with a vengeance this summer. The new aquatic weed harvester, a more eco-friendly removal method, hopes to clear it for good soon.

Berg emphasized the improvement the lake has seen since beginning endothall treatment, and expressed some concern about maintaining that headway during the transitional phase.

“I’ve heard that in the 1980s, the lake was unusable. It was so choked off with weeds and floating algae and whatnot,” Berg said. “We've made tremendous progress over the years and we want to keep the lake in good shape.”

Schoen stressed that the decision to shift away from endothall does not mean the lake will be neglected or under-managed.

One form of treatment the city will continue to implement at Half Moon is the use of the mineral "alum" to combat high phosphorus levels. According to historical records, the lake used to be home to several saw mills which deposited sawdust into the water, Berg said.

“As (the sawdust) continues to break down, we end up with high levels of phosphorus,” Berg remarked. “Alum binds with the phosphorus. Without the alum, the lake would turn green in no time.”

Berg said his department is looking ahead toward these future changes. Schoen added that the city council will continue to prioritize environmental issues as they work on future policies.

For more information on the Half Moon Lake (615 Randall St., Eau Claire) cleanup fund passed by Eau Claire City Council, visit www.eauclairewi.gov, or check out the council members’ Facebook pages.