The Department of Natural Resources has approved an aerator, tentatively denied a re-circulator and is considering a possible drawdown of Pigeon Lake in Clintonville.
Deteriorating conditions at Pigeon Lake have been a topic of discussion for the past few years between the Pigeon Lake Protection and Rehabilitation District (PLPRD) and the DNR.
The two groups are trying to come to an agreement that is acceptable to both sides for the improvement of conditions at the lake.
“I’ve been involved with Pigeon Lake for almost 12 years, dealing with different issues or improvements that have taken place over the years,” said DNR Water Management Specialist Scott Koehnke. “We’ve had discussions going back to 2004 about how to address issues common to mill ponds like Pigeon Lake.
“Pigeon is not unlike any other mill pond in the area-it’s a river system that people have tried to turn into a lake by using a dam,” Koehnke stated. “Mother nature says, ‘No way, I want this to be a river.’ So the mill pond gets filled with sediment, and that’s what will continue to happen until the lake fills up.”
The PLPRD and DNR have talked about draw downs, harvesting weeds, using chemicals, sediment removal, and any other possible option. There are pros and cons for each option. The DNR says it has seen success with drawdowns in surrounding areas. This solution is has a reduced cost. In Clintonville’s case, the cost is next to nothing-it doesn’t cost the city anything to open up the dam. Permits do have a cost, but the physical work is just opening up the dam.
There is a significant amount of resistance to the drawdown method, so the PLPRD is looking at trying other methods. An aerator system on Brady Lake was approved. An application has been submitted to the DNR for a re-circulator for the Fairway Lake portion of Pigeon Lake. The DNR has made a tentative decision to deny that permit request.
“The aerator permit is different system than the re-circulator,” commented Koehnke. “It’s elevated off the bottom of the lake and puts air into the water column. It doesn’t mix in a vigorous manner and doesn’t re-suspend sediment-it just puts bubbles into the water that help in the digesting process. The re-circulator has a propeller that spins at a high rate of speed and will likely re-suspend sediments. When you turn them on, they draw water up from the bottom. The mechanism spins at such a speed that it will pick up material in shallow water and act like a blender, throwing it outside the device’s zone of influence.
“In a mill pond system, re-suspending the organics and clays into the water column has secondary outcomes that are not good for fish, water quality, or the aesthetic interests of property owners. We’re trying to tell the PLRPD that Pigeon Pond is not the type of setting for re-circulator equipment-that’s the difference between one permit that is approved (the aerator system) and one that’s potentially denied (the re-circulator system),” explained Koehnke.
“We have been speaking to the PLPRD for a couple years about re-circulator equipment,” continued Koehnke. “We have had concerns from the beginning. We’d hate to see them spend time, money and energy on a product that isn’t going to provide what they’re looking for in terms of relief. They still wanted to go through with the permit application process, so we asked them for additional information on their proposed project, stating that we’re not confident this system would be able to do what they wanted it to do. Based on the information they provided, the DNR isn’t convinced it’s going to work, so we made a tentative decision to deny the permit.
“All the literature we’ve read says re-circulator systems work well in deep waters. These products do well in organic digesters, manure pits, and other places where you don’t have a concern for water quality or fisheries. Those in favor of using this system say it will chew up sediments and vegetation, but the river is continually transporting these things into the mill pond. There’s no way for that equipment to stay in front of what’s coming into the lake. Re-circulators have a purpose, but not in this type of setting,” said Koehnke. “Pigeon Lake isn’t a deep lake-it’s a river with a dam on it. It looks like a lake but still functions as a river. Rivers and streams are natural sediment/nutrient transport systems-all that’s currently in Pigeon Lake would have left the system if not for the dam. So, we still think a draw down is the most effective and best management option for Pigeon Lake.
“Many mill ponds have been let go for 20 or 30 years with little or no management, and now they have sediment and vegetation problems,” said Koehnke. “If you draw them down, you can minimize areas you need to work on. The PLPRD can continue to harvest weeds, do chemical treatments, or install aerators via permit-this is all voluntary. But when they come to the DNR and ask for options, a drawdown is going to be a strong option. There’s no question that there’s sediment coming into the pond-everything that was in the Marion Pond is now in Clintonville, because they had vegetation and sediment issues, and they did a draw down, so everything flowed down to Pigeon Lake. We have not nor could we hold the PLRPD hostage. If a re-circulator could be used in a situation that didn’t have secondary impacts, we’d allow it. We know re-circulators work for certain things, but we are making a decision based on the impact it will have on resources.”
“When you go back 20 or 30 years ago, you didn’t have larger boats with 200 horsepower motors; there weren’t as many people living on the lake; we didn’t have zebra mussels and other exotic species,” Koehkne said. “I don’t doubt that the lake was in much better shape-I’m sure it offered great recreational potential. But, as a society, we’ve taken such a hands off approach towards mill ponds, because we think, ‘It looks like a lake, so it must be a lake.’ But it’s not. It gets to a breaking point, and that’s where we’re at now. Fairway Lake used to be 8 feet deep, but now the deepest part is 4 feet deep. It’s filling in.”
Koehnke noted that the DNR has worked with other lake districts to conduct draw downs in Marion, Weyauwega, and other surrounding areas that have mill ponds. “We’ve seen positive results,” Koehnke stated. “It’s a tool that we know will work, and it’s the cheapest option. The DNR is not forcing the PLRPD to do a draw down-they actually came to us with a draw down proposal and we were talking about depths of draw down before the re-circulator came into play.”
If a drawdown is employed, fish re-stocking will likely be needed. Al Niebur, DNR fisheries biologist, said that in the event of a draw down, some fish will go upstream, some will go downstream, and some will stay in the river channel in the Pigeon Lake.
“The population can recover on its own over time,” Niebur said. “What we do when we re-stock fish is we try to augment that process. Usually we re-stock bass and northern. The pan fish species can recover on their own quite rapidly.”
Niebur is also a PLPRD resident, and he feels that all options for the lake need to be considered.
“Our leadership needs to weigh the pros and cons of all options,” he said. “I’m concerned. I feel like the re-circulator isn’t right for Pigeon Lake, and based on the cost, I don’t think it’s a worthwhile option. I’m in favor of a drawdown because I’ve seen it work in other cases. We have to think long-term. Yes, there will be a short-term impact that results from a draw down, but we have to look ahead. The lake is collecting sediment and it needs to be flushed out. No solution will be 100 percent successful, but we have to work together to manage the health of the lake.”
PLPRD President Dennis Krueger said a public hearing may be scheduled to address sediment problems in Fairway Lake and get public input. The use of a re-circulator system will also be discussed.
“I think the re-circulator works great in its right place,” Krueger said. “But, the DNR has tentatively denied our permit request based on the depth of the water. If the lake was a lot deeper, it might work, but we don’t have much depth at Fairway. But that’s not to say we can’t try a surface or fountain aerator. We need to consider all of our options.”
“The PLPRD board has been bifurcated in the sense that there is a group in favor of a draw down and there is a group in favor of using a re-circulator. There are people that have left the board in frustration just because of the direction the board was going,” said Koehnke. “It’s not a unanimous type feeling that they really want to go through with the re-circulator. There is a local businessman who stands to gain financial onuses if it goes through. I’ve been involved in the discussions, and the board is not 100 percent in agreement on what direction to go.”
PLPRD Secretary Jerre Cummings said the board is considering writing letters to state legislators and DNR Secretary Cathy Stepp. “I disagree with the DNR when they say the river flowing through has a strong enough effect on Fairway Lake. I live right on Fairway Lake, and the flow through isn’t enough to impact that part of the lake. Some feel like there is a double standard-it’s ok to move sediment by draining the lake, but not ok for us to disturb it with another tool such as a re-circulator. There are a lot of different opinions and we need to all come to an agreement before we proceed.”
The PLPRD board will hold their next meeting at City Hall on Thursday, Aug. 18, at 6:30 p.m.