Marsh Lake project completed
It has taken some time, but the Marsh Lake Ecosystem Restoration Project has reached its completion. Last Thursday, on what proved to be a very windy day at Marsh Lake, long-time DNR employee Walt Gessler invited some intrepid local reporters to Marsh Lake to take a tour of the lake and view the effects the project has had on the lake and nearby wetlands.
The project was a collaborative effort between the U.S. Army Corps of Engineers, the Minnesota Department of Natural Resources, and the Upper Minnesota Watershed District. The actual construction part of the project began in 2016, with discussions and research beginning in 2011.
According to Gessler, there were four major aspects of the project: the restoration of the Pomme de Terre River to its original pre-1930s channel; constructing a rock fishway; constructing a new water control structure; and building a new access road and embankment.
“The purpose of the project was not to restore the area to 100 percent the way it was before the 1930s,” said Gessler. “Instead, it was to eliminate the flow of sediments and farm nutrient runoff into the lake. Each of these parts of the project will improve and enhance the ecological systems and habitat that have been harmed over the years.”
In 1938, the Pomme de Terre River was rerouted from its original channel to empty into Marsh Lake as part of a government project to put men to work during the Great Depression. At the same time, a fixed-level dam and embankment were constructed to control downstream flooding.
Gessler pointed out the newly constructed fishway, which consists of semicircles of boulders. The boulders increase in size from further away and become larger toward the dam. “This fishway will allow many species of fish to migrate into Marsh Lake from Lac qui Parle Lake.
Walking a short ways downstream from the fishway, Gessler stopped at the confluence of the Pomme de Terre and Minnesota Rivers. The Pomme de Terre was flowing at a fairly fast rate last Thursday.
“The water is flowing really good today,” Gessler said. “Previously, this part of the old river channel served as nothing more than an overflow backwater for the Minnesota River.”
In order to return the river to its original course, the 1930s-era embankment had to be breached, which made the access road to the old dam area unusable. This in turn made it necessary for a new portion of embankment to be built, as well as a new access road.
From the breach, Gessler began the tour by heading around the northeast side of Marsh Lake, occasionally stopping to point out areas of interest. One such area was what had been a shallow bay before the drawdown. He said: “This area had been filling in with sedimentation over the years and was a non-supportive wildlife habitat.”
Throughout the former bay, vegetation has been taking root. “By September, this entire area will be full of head-high plants which will provide an improved habitat for wild life.
A short ways further down the road, Gessler stopped to point out a crystal clear backwater pond. “Last year at this time, you couldn’t see into the water,” he said. “Carp had gotten in there and muddied up the water. The carp were removed, and the water cleared up.”
Across the road was another pond, which contained carp. The difference was striking. The water was heavily sedimented and could not be seen into. “Carp got in here, and you can see how muddy the water is,” Gessler said.
The draw down has exposed large portions of former shallow lake bed, which are now seeing increased vegetation. At one such spot on the west side of the lake, Gessler walked a long ways out on the lake bed.
Deer trails to what were once islands were criss-crossed by coyote and other mammal tracks. “This entire area will become prime habitat for all kinds of animals and birds,” he said. It will be covered in vegetation come fall.”
After several more stops to look at how the draw down has affected the lake, Gessler made his way to the west side of the new water control structure, where water was flowing through the gates at a steady and rapid rate. He said: “This control structure allows us to control the level of the lake. If the level becomes too low, we can close the gates to raise the level of the lake. If it’s too high, we can open them up to lower the level as needed. The fishway on the other side also works to passively control the water level.”
The result of all the planning and construction will be a more natural and vibrant habitat for all wildlife, which when all is said and done, benefits everyone.