A lakes biologist from the state Department of Natural Resources spent an hour and a half with Algoma area residents Monday afternoon (April 1) explaining and answering their questions about what they can expect to happen during and after a planned two-year drawdown of the Forestville Millpond.
Ted Johnson appeared at Algoma City Hall at the invitation of state Rep. Joel Kitchens, R-Sturgeon Bay, who emphasized at the outset that he organized the meeting to explain the process, not second-guess the drawdown decision, which was made by the Door County Board and did not involve either the DNR or the state Legislature.
“In fact, the DNR did not want him to come initially, because they didn’t want him to be beaten up for the decision when he had nothing to do with it,” Kitchens said. “They said they would do it if I would facilitate it.”
His warning did not dissuade several vocal opponents, and Kitchens cut off questioners several times when their remarks strayed into the area of criticizing the Door County Board’s decision.
Johnson said he has been involved with about a dozen drawdowns over 25 years with the DNR and that the process of emptying a manmade lake can be very good at controlling infestations of Eurasian watermilfoil, an invasive species that grows in still or slow-moving water. As a result a drawdown can improve species diversity and the quality of native submerged plants once the lakebed is refilled, he said.
The drawdown can also increase fish and wildlife habitat and improve the depth of the lake, especially as the river cuts a stream channel through the area while most of the pond is empty, Johnson said.
“The maximum improvement in lake depth happens when the lake’s drawn down during a hot summer and a dry summer,” Johnson said, because the exposed bed dries out and is compacted.
A drawdown in Lake Weyauwega in 2012-13, for example, improved the average depth by nearly two feet. That drawdown lasted two summers and one winter.
Door County plans to drawdown the 94-acre millpond for two winters and two summers starting in November of this year.
It’s important for a drawdown to be “a slow, metered release” of the waters, reducing the level no more than 3 or 4 inches per day, and he downplayed the concern that a great deal of sediment will be washed into the lower Ahnapee River.
“Most sediment will deposit in slack water or low-energy environments, not the main river channel, or the floodplains of the Ahnapee River, and some will make it to Lake Michigan,” Johnson said. “I’ve had some people think that all the sediment from the millpond is going downstream. You’re talking about a stream channel that’s cutting through it; the rest of (the sediment is) going to stay in place. And when that terrestrial vegetation comes in, that’ll hold it in place, too.”
The drawdown process generally has short-term impacts – mainly with regard to aesthetics and economics – but long-term improvements, he said.
A meeting and training session planned between Door County and DNR officials on Tuesday (April 2) will focus on monitoring conditions in the millpond before, during and after the drawdown, Johnson said.
“It’s really important to study what happens so it’s not anecdotal and people know exactly what really happened with this,” he said. “Areas to consider are water quality upstream and downstream.”
Among issues raised during the question period, retired conservationist John Rybski asked how soon the Eurasian watermilfoil may return to the pond, citing what he said was a resurgence of the invasive about 10 years after a drawdown in the mid-1980s. Johnson said milfoil has stayed away after the drawdowns in his experience.
Rybski and others challenged Kitchens and the state Legislature to develop policy that requires counties in a watershed to work together on such projects. Kewaunee County residents have said Door County made the Forestville Dam decision without much feedback from their downstream neighbors.
“I’ve been to a couple meetings about this issue, and this is the first one where there was a substantial amount of questions and answers, and I feel like I understand both from your presentation and the questions the potential impact compared to actual trials in other locations than I did before,” he said. “I really feel this particular situation is kind of a golden opportunity to do some policy work (in the Legislature) for us to look at our streams and our lakes on a watershed basis and not on the basis of arbitrary political boundaries that have nothing to do with the geology.”
Photo: State Rep. Joel Kitchens, right, introduces lakes biologist Ted Johnson of the state Department of Natural Resources at the start of an informational presentation about the coming drawdown of the Forestville Millpond along the Ahnapee River.