Flush with vegetation, restored Marsh Lake will welcome migrating ducks this fall

Win Mitchell has lived long enough to see the good times, bad times and good times again on Marsh Lake, a 5,000-acre bulge in the Minnesota River.

Now he's seeing the good times ... with vegetation.

In advance of Saturday's regular-season duck opener, Mitchell, 79, of Northfield, past state chairman of Ducks Unlimited, was on Marsh Lake on Friday, scouting the large, shallow — and reborn — western Minnesota water body with a buddy, Pete Bohlig, 48, of Farmington.

"It looks entirely different from last year," Mitchell said. "A lot of vegetation has grown up."

The object of more than 20 years of planning, funding and construction, Marsh Lake is primed to welcome migrating ducks in October and November. But on Friday, Mitchell said, it didn't hold enough birds to warrant his and Bohlig's attention on the opener.

So when the sun crested the eastern horizon Saturday, the pair, along with Pete's Chesapeake Bay retriever, Penny, were aligned alongside a wetland lying within a nearby state wildlife management area.

"We saw a good number of teal," Mitchell said. "Pete and I managed to bag eight — seven bluewings and a greenwing."

Later this fall, when Mitchell and Bohlig motor onto Marsh Lake in Bohlig's mud boat, they hope the lake is a magnet for mallards. In its distant past, as many as 80,000 mallards called the lake home or used it during migration.

But Marsh Lake was fated to degrade nearly from the time it was created by construction in the late 1930s of a flood control dam.

Rather than prevent flooding, the fixed-crest dam stabilized the water level behind it, stifling the types of emergent and submergent vegetation ducks and other aquatic wildlife need. Created instead was a world-class carp factory.

"Carp are strong enough," said Department of Natural Resources wildlife area manager Walt Gessler, "that they could jump over the dam or otherwise get into Marsh Lake. Most other fish couldn't."

Gessler oversees Lac qui Parle Wildlife Management Area, a 24,300-expanse of public land that includes Marsh Lake.

Finally complete, about 60% of the Marsh Lake project's approximately $13 million cost was paid by the federal government, with the remainder picked up by funds provided by Minnesota's Clean Water, Land and Legacy Amendment.

Owned by the federal government and managed by the U.S. Army Corps of Engineers, the dam could have been replaced by an operable spillway with less cost, but fewer benefits.

Instead, following a 2005 study by the Corps that determined the federal government would help restore Marsh Lake's ecosystem and a follow-up study in 2011, funds were appropriated to the Corps to complete the Marsh Lake plan. Construction began in 2019.

The project's cornerstone is a massive water control structure that can periodically draw down the lake. The intent is to simulate periodic natural drought conditions that promote plant growth from seeds lying dormant in the lakebed.

Drawdowns also kill carp.

"We started a drawdown — with the new structure — in 2020 and ended it last year,'' Gessler said. "We didn't kill every carp in the lake, but we killed a lot. It was quite a field day for eagles and raccoons and other predators."

This "reset" of the lake's carp numbers will contribute to cleaner, clearer lake water and increased populations of walleyes, bluegills and northern pike. Construction of a 300-foot-long "rock arch rapids'' and ramp fishway helps these game fish enter the lake, as they did before the old dam was built.

This spring, Gessler said, DNR fisheries biologists found "a lot" of young northern pike in the lake. The hope is they prey on young carp.

Critical also to the project was a rerouting of the Pomme de Terre River to its original channel, so it no longer flowed into Marsh Lake, adding some 19,000 tons of sediment to the lake each year. Bank reinforcement of the new channel was required, and special mats consisting of sod, woody debris and logs were installed.

Additionally, thousands of mussels were relocated in the river. The mussels were found primarily by "pollywogging," or crawling along the river channel by DNR and Army Corps staff and volunteers, and feeling the bottom for mussels.

A concern throughout the project was the presence on islands in Marsh Lake of Minnesota's largest breeding colony of American white pelicans. Would they find enough to eat if the lake was drawn down? Would they have enough water to take off and land?

"It was something we watched closely during the drawdown," Gessler said. "From what we could tell the pelicans continued to nest and were successful in having their young. Perhaps not as many, but generally successful."

Last duck season, after the drawdown sparked growth of sago pondweed and other food ducks devour, hunting was fabulous on Marsh Lake. This year, the lake looks entirely different, with the presence of so many cattails.

Gessler said the second-year vegetative growth was expected and provides various benefits, perhaps especially by reducing "wind fetch," which contributes to erosion and particularly sediment suspension in the lake.

The latter leads to cloudiness, or turbidity, which inhibits vegetation growth.

"Marsh will be a great lake again, not just for ducks but for fish, pelicans, shorebirds and other wildlife," Mitchell said. "It took a long time. But the DNR, the Corps and the Upper Minnesota River Watershed District did great work."

Then, Saturday morning, Mitchell said, "Now Pete and I have to clean ducks."