Posted on September 24, 2025
ALTOONA — Two projects addressing critical parts of Lake Altoona in 2026 will require a draw down, significantly lowering water levels down by eight or nine feet in the fourth quarter of the year.
In one area, the dam connecting Altoona Lake to the Chippewa River requires repairs and maintenance in a couple of key areas.
“The tainter gate painting was marked as something that we needed to do, which is the biggest portion of the project, at least cost-wise,” Josh Pedersen, parks and forest director for Eau Claire County. “And in each of the ogee spillways on the tainter gates, there’s some concrete spalling and a few sections where there’s rebar exposed.”
The paint on the tainter gates plays a significant role in the dam’s stability. Water and metal often do not mix well after a while, so the paint helps prevent corrosion of the gates holding back all of Lake Altoona.
At the back side of the gate is where the ogee spillway is, which is designed in an “s” shape to help water flow smoothly.
For the second project in 2026, the Lake Altoona District plans to dredge 169,000 yards of sediment from its delta. A lot of the sediment and debris that has been picked up where the water flows into Lake Altoona has created difficulties at that part of the lake, said Michele Skinner, chair of the Lake Altoona District Board.
“That impacts boating navigation, recreation, our fisheries, the connectivity of the lake between the river and the lake. We need to keep that open,” she said. “If it just keeps filling up with sand, the lake loses water. And then we lose the ability to hold back water in the case of flooding to protect downtown Eau Claire, which is downstream.”
“The philosophy is all dams are temporary if we don’t actively try to mitigate some of that sedimentation that occurs,” said Noah Edlin, park supervisor for Eau Claire County. “A part of a natural watershed is to have some sediment flow down the river.
“We have some really tight corridors and big falls that have a lot of speed. So it will grab that sand and it will carry it a good distance until it hits something like Lake Altoona, that it’ll go from that high flow to low flow. Right there, it will constantly drop out that sediment. And what will happen is it’ll slowly crawl forward towards the dam itself.”
By dredging it, built-up mud, weeds and rubbish would be scooped out to prevent further negative impacts to the lake’s habitat, recreation and more.
“And [dredging is] probably one of the best ways to manage a lake that we’ve found,” Edlin said. “We haven’t ever found a perfect solution on how to deal with that sediment that flows downriver.”
To address both areas, plans are being worked on to create a draw down, slowly starting in early September 2026, that would lower Lake Altoona by eight or nine feet by Sept 30. At its deepest point, Lake Altoona is 25 feet deep.
During that time, the boat launch would be closed and ice fishing in later months would likely be prohibited. The water would have to be raised back to normal before fish spawning season begins on March 1, 2027.
“But hopefully they understand that doing this will protect the fishery for years to come,” Skinner said.
Pedersen added that the lowering of Lake Altoona’s water level may also serve as an opportunity for people to do their own maintenance if they live on or have things on the waterfront.
While hydraulic dredging would be an option to address Lake Altoona’s delta without lowering the water level, it comes at a significantly higher cost. Through the coordination of both projects, both areas could be addressed without having to draw down the lake twice.
For dam work, Pedersen said costs are expected to come in at around $800,000 funded by the Eau Claire County to paint gates at Lake Altoona and Lake Eau Claire, replace generators at both dams and to lay concrete at the Lake Altoona dam.
For the dredging work, Skinner said costs are estimated to be at over $1 million funded by the Lake Altoona District. The last time dredging was budgeted for was in 2016, which was also the last time Lake Altoona’s water levels were lowered by doing a draw down.
