By Jennifer Kotila
COKATO, MN Anybody driving past or stopping at the Smith Lake public access this spring was treated to a lake that was full of waterfowl.
Smith Lake, a 330-acre shallow basin located north of Highway 12 on Wright County Road 5, is in the process of a drawdown in order to improve wildlife habitat.
The drawdown is coming along quite well, and the lake has been collecting a lot of wildlife already, compared to before the project started, said lakeshore property owner Dan Nyquist.
“It’s likely low water levels this spring made some food sources more available,” said Ducks Unlimited biologist Josh Kavanagh.
“Waterfowl use on the lake this spring was unprecedented for this lake based on prior years, and as of late last week, there was an abundance of trumpeter swans and pelicans still utilizing the lake,” said Bart Bly, Wildlife Lake Specialist for the Minnesota Department of Natural Resources (DNR).
Why the drawdown is needed
Smith Lake was labeled a “designated wildlife lake” by the Department of Natural Resources (DNR) in 2009, one of roughly 40 Minnesota lakes to have received that designation.
Due to an abundance of invasive fish, Smith Lake has been in a very turbid, degraded state for years, no longer supporting migrating and brood-rearing waterfowl.
Six years ago, a fish barrier, called a velocity culvert, was placed downstream in order to prevent invasive fish, such as carp and bullheads, from entering into the lake, according to Fred Bengston, DNR wildlife supervisor.
A velocity culvert is a culvert that is placed at a certain grade which fish cannot swim up.
While the fish barrier worked well to keep new fish from entering Smith Lake, Bengston said there has not been a significant enough winterkill to rid the lake of the invasive fish that were already there, such as bullheads and carp.
It will also promote the germination and growth of aquatic plants and invertebrates favored by ducks and other wildlife, according to the DNR.
Results of the drawdown this spring
The DNR documented an abundance and diversity of migrating shorebirds using the lake as a stopover site this spring, which was very impressive, Bly said.
Some of the waterfowl making a stop at Smith Lake are fairly unique to the area, Kavanagh said. They were attracted to the extensive mudflats exposed by the drawdown.
Mudflats are the areas around and in the lake where receding water has exposed the land.
Reptiles and amphibians were also documented utilizing the lake, suggesting that the water level management will have broad-reaching, positive impacts for a wide variety of wildlife species, Bly said.
Although the heavy snowfall last winter slowed the progress of the drawdown slightly, it also increased the severity of the winterkill of bullheads, which was one of the major goals of the drawdown, he added.
Nyquist has found that there are still some minnows in the lake, meaning it will have to remain low for at least another winter to kill them off, he said.
“Hopefully conditions this winter will allow for a complete winterkill of undesirable fish, including carp and bullheads,” Kavanagh said.
This spring, the DNR seeded Smith Lake with hardstem bulrush, which is common wetland vegetation.
The DNR will be seeding the lake with wild rice in late summer.
“If these plants become established on Smith Lake, it will only further add to the improvements for wildlife habitat we will have made on the lake,” Bly said.
“I anticipate the exposed mudflats turning bright green and lush with a variety of moist soil plants this summer,” Kavanagh said.
The construction of the water control structure is now complete, with only a little bit of cleanup and seeding left to do near it, Bly said.
“We, as an agency, hope that the success we have been documenting in terms of wildlife benefit and water quality on Smith Lake will serve as a model example for how shallow lake management can benefit other impaired lakes throughout the state,” Bly said.
“Local support has been tremendous, and strong partnerships have been key in making what figures to be an extremely successful project,” Kavanagh said.
“Everything went well with the DNR and Ducks Unlimited,” said shoreland owner Dennis Larson. “I expect in a few years, there will be plenty of vegetation, and the water will be cleaner.”