It will take time for the weeds to disappear on Lake Iola.
This information was presented by Wisconsin Department of Natural Resources representatives at the Lake Iola Lake District meeting on Sept. 24.
Members of the lake district were concerned because Lake Iola appears to be very weedy after the recent drawdown.
“Did you know it would be this bad?” asked Bob Dix, a lake district member.
“Your plant response was the best I’ve ever seen,” said Ted Johnson, a DNR biologist. “You had a massive plant response because you did a drawdown. You need to be a little patient.”
“A lot of the grass you are seeing is already dying,” he explained. “Terrestrial plants can’t live in deep water.”
Although they may look healthy, he said the saplings and grass that are underwater are stressed and will eventually die.
According to Johnson, the lake will look better next year, and even better in two years.
The presence of cattails and water lilies were a concern of some of the people who attended the meeting.
These will die out in the deeper water, Johnson said. He noted that with past drawdowns, pond weed population does not tend to change and does not disappear entirely from a system.
“Milfoil, on the other hand, will come back with a vengeance,” he said.
Johnson noted that milfoil was not present on Lake Iola. “This is good news,” he said.
According to the DNR representatives, the lily pads were present prior to the drawdown, so they will still be present in the lake.
Vicky Bellows asked what can be done about the canary grass.
“Anything exceeding a foot of water will not make it,” Johnson said. “It is a wetland grass, so it may take up to two years (to die).”
Lake District members wanted to know why the lake looks so weedy. They had expected the drawdown over one summer and two winters to kill most of the weeds.
“Is it mostly because we didn’t bring the lake up until later (in the spring)?” Jerry Harvancik asked.
Johnson agreed that the lake would have looked better if the drawdown had ended earlier in the spring, as planned. He also noted that the lake was not drawn down to the level the DNR had recommended.
Both of the factors were due to problems with the dam and drainage issues.
“I think we had a successful drawdown as far as the river bed,” said Marlin Mayer. “The trade off is we have a lot of sediment in the channels and sides.”
Fish population
The members of the Lake District asked, “When will the fish come back?”
The DNR will continue to monitor the fish population, according to Al Niebur, DNR senior fisheries biologist.
“We did do some stocking,” Niebur said. “They should grow pretty fast.”
He noted the DNR only stocked game fish like Northern Pike and Large Mouth Bass. Normally there is no need to stock the panfish species.
“We didn’t do much management with those species,” Niebur said. “They tend to establish themselves.”
One lake district member reported seeing a 12-inch bass.
“We want the game fish to come back so they can control the panfish,” Niebur said.
He noted this may take up to four years.
“Early this spring in the outflow we saw literally thousands of fish moving into the lake,” said Tom Fucik, who monitors the dam. “I was astounded. They were moving upstream through that bottom valve system.”
Continuous monitoring
The DNR is monitoring Lake Iola and plans to check the elevation levels this winter.
“There will be a lot more information coming later,” Johnson said.
Next spring, the DNR will look at individual properties to assess weed populations. At that time, the lake district can apply for a permit to chemically treat areas of the lake, if necessary.
Chemical application must be by a certified person. For Lake Iola, the application is usually done by Cliff Schmidt.
Although the lake district gets the permit, “Shoreline restoration is at the cost of individual homeowners,” Harvancik said.
Schmidt said a permit is not needed to use some granular chemicals.
Johnson noted there are liability issues, and recommended that landowners not apply granular chemicals.
Schmidt noted he usually charges about $40 for 30 feet.
“For that price, why risk it?” Harvancik said.
With the presence of sediment, lake district members asked if dredging would be recommended.
“In 90 percent of situations, you can’t afford it,” said Scott Koehnke, DNR water management specialist. “There could be hazardous materials so there’s a risk and a cost factor involved. Dredging projects are pretty huge and costly.”
According to Koehnke, most of the cost is paying to dump the hazardous waste. He also noted that the second the machine is turned off, the sediment begins to build again.
“From a cost standpoint, opening the bottom draw pipe is a better management choice,” Koehnke said. “If you can get a bottom draw working on a dam, the sediment will move.”
Mayer asked what could be done to take out some of the silt buildup.
“A certain amount of sediment comes in every year,” he said. “We aren’t gaining on it now – we’re losing ground.”
One solution is to install a silt trap.
“Silt traps are a short-term impact,” Koehnke said. “In a large river system like this, it’s filling in as you’re dredging out. So it wouldn’t be worth the effort or the cost.”
A mill pond is like a gold fish bowl, according to Johnson.
“If you don’t do anything to a goldfish bowl, sediment builds and the goldfish die,” he said.
“Every day you have to manage that mill pond,” Johnson said. “It’s a constant management technique.”
He said the drawdown moved a lot of sediment and Lake Iola is a “productive habitat again.”
“We voted for the drawdown. We did the drawdown,” Harvancik said. “It is what it is and now we have to ask everyone to be patient.”
He noted the drawdown gained about 6 to 8 inches of depth in the lake,