Marsh Lake is working again. Water is percolating out of the famous reservoir faster than the Minnesota River is flowing in.

Before long, duck hunters, anglers, naturalists and bird watchers will start to realize a dream conceived more than 20 years ago: returning the degraded, carp-infested Marsh Lake to its previous grandeur as a waterfowl and shorebird mecca.

“All the major features are complete… there is hope on the horizon,” said Clay Tallman, Army Corps of Engineers project manager for the $13 million ecosystem restoration in far western Minnesota.

It’s still too soon for the project’s partners to hold a public dedication, but insiders at the Army Corps, Upper Minnesota Watershed District and Department of Natural Resources (DNR) received slaps on the back earlier this month from Dave Trauba, the DNR’s regional wildlife manager.

“We did it, folks!” Trauba wrote two weeks ago in a mass e-mail. “For some, this has been a 3-year ordeal; for others 20-plus years to get to this day.”

Already happening is a gradual draw-down of the 5,100-acre wide spot in the Minnesota River, enough to expose vast amounts of old shoreline. The lake’s natural hydrology is to ebb and flow with climate conditions, but a fixed-crest dam built in the late 1930s drastically interfered with those cycles.

Too much water in the shallow basin — made turbid by carp and winds stirring up the bottom — destroyed the natural balance of plant life that once attracted as many as 80,000 mallards. A deep draw-down will allow native plant seeds to sprout again, returning emergent and submergent vegetation to help clean the water, support a diverse fish population and feed wildlife. Meanwhile, mud flats will reinvite an abundance of shorebirds. Marsh Lake also acts as major rookery for pelicans.

“For us, success is going to be able to see that pulse of vegetation … more balance,” Trauba said.

Citizen advisory committees for a troubled Marsh Lake were formed as early as the 1990s. There had been intermittent years of severe drought that caused the lake to recede. When rains filled it up again, there’d be flashes of good vegetation to draw ducks. The earliest talks to fix the lake centered on building an operable spillway to mimic the droughts.

Looking back, Trauba said that was the project’s biggest fork in the road. He’s proud that the Army Corps and DNR chose a higher degree of difficulty. After a major environmental assessment in 2011, planners settled on a three-fold plan:

• Build a concrete structure allowing for the southerly release of water into Lac qui Parle Lake and the Minnesota River.

• Reroute the Pomme de Terre River to its original channel below Marsh Lake Dam. (It was diverted decades ago into Marsh Lake for flood control.)

• Introduce a 300-foot-long “fishway” for walleyes, northern pike and other species to migrate between Marsh and Lac qui Parle lakes.

Congress gave the true go-ahead in 2014, unlocking $7.6 million that Sen. Amy Klobuchar famously said would “put the marsh back in Marsh Lake.” Minnesota’s Outdoor Heritage Fund kicked in $4.63 million, or 35 percent of the total cost. When construction began three years ago, record rains caused setback after setback. “Credit to the Corps as they never sacrificed quality,” Trauba said.

Win Mitchell, a former state chairman of Ducks Unlimited, said the last good year for ducks at Marsh Lake was 1999. He’s looking forward to the lake’s comeback.

“It was the natural cycle of wet and dry that made the lake produce like it did,” Mitchell said. “This will create fresh water, and that’s what you need.”