ASHBY, MINN.

Brad Gruss was all smiles after Minnesota's duck opener Saturday. ¶ And he never fired a shot. ¶ Gruss, 60, hunkered with two friends on a historic spit of land he owns on Christina, one of the state's legendary waterfowl lakes long troubled by tainted pea-green water.While shotgun blasts echoed across the 4,000-acre shallow lake a half-hour before sunrise Saturday, nary a duck flew over Gruss and pals Doug Huberty and Tom Warnke. They weren't dismayed, because their morning hunt -- and those of other hunters around the lake -- was unprecedented.

"We're hunting on ground that has been submerged for 70 years," Gruss said.

And they believe they are witnessing the rebirth of Christina -- one of Minnesota's most important and famous waterfowl lakes, a place rich in wing-shooting lore.

The long-sick waters, a victim of turbid high water caused by rough fish, is being restored though a new $2.3 million pumping system that has lowered the lake 2 1/2 feet, exposing shoreline and mud flats, some for the first time in recorded history.

"It's lower now than it was in the 1930s Dust Bowl-era," said Tom Carlson, waterfowl habitat specialist for the Department of Natural Resources.

The goal is to mimic nature by causing much of the carp, buffalo fish, bullheads and minnows to die this winter either because the shallow water freezes solid or from lack of oxygen.

The rough fish uproot vegetation on the silty lake bottom, resulting in cloudy water, which then kills off the sago pondweed, wild celery and chara that attract and feed ducks. That includes great flocks of canvasbacks that once fueled themselves at Christina during fall and spring migrations.

"When the lake is healthy, the water is gin-clear," said Gruss, who has lived on the lake since 1994 and is active with the Christina-Ina-Anka Lake Association, a 200-member group named for the three adjoining lakes. It spearheaded the campaign to restore Christina.

"Without them, the project wouldn't have happened," said Jon Schneider, manager of Minnesota conservation programs for Ducks Unlimited.

Of the $2.3 million for the project, $1.5 million came from the state Outdoor Heritage Fund, $296,000 from Ducks Unlimited, $287,000 from the lake association and $170,000 from the DNR.

Why spend all that money?

When Christina is in its prime, up to 20 percent of the continental canvasback population stop to feed and rest there. Redheads, bluebills, ringnecks and mallards come, too.

"I've been here when there's 200,000 cans on the water," Gruss said. "They're the king of ducks. But there's nothing for them to eat now."

However, next spring, with most of the fish gone, the water should be clear, the vegetation should flourish -- and the ducks should return.

That's what happened after fish in the lake were poisoned by the DNR in 1965, 1987 and 2003.

But the rebound always was temporary.

"We've finally solved the root cause of this -- water levels," Gruss said.

Christina has been plagued by high water since the drought of the 1930s when a dam was built at the outlet to Pelican Lake, which Christina flows into, to retain water levels. But that has prevented Christina from going through natural wet-dry cycles.

The new pumping system, started in July, will be used to retain high-quality water on Christina. The hope is that after this season, the pumps won't have to be turned on for years. But Christina won't be allowed to deteriorate again.

A revitalized Christina should boost duck numbers in the entire area, said Carlson. And it will send cleaner water downstream to Pelican Lake, a recreational fishing lake.

This fall, the lack of water will make access for duck hunters difficult. But Gruss and other hunters who filled the many historic duck camps around the lake last weekend said they are willing to pay that price for a revitalized Christina.

Those mud flats should be covered with clear water and lush vegetation next fall -- a salad bar for ducks.

"I'm 100 percent convinced it will work, the ducks will come back, and Christina will be a jewel again," Gruss said.

Doug Smith • dsmith@startribune.com