A year ago, frozen Pelican Lake in Wright County was bustling with hundreds of anglers catching crappies, sunfish and northerns.

It was the hottest fishing hole in the county.

Today the sprawling 3,800-acre shallow lake, about five miles west of St. Michael, is empty of both anglers and fish.

"Essentially no one is fishing the lake," said Fred Bengtson, Department of Natural Resources area wildlife manger.

Which is no surprise, because the DNR has started a multiyear $2 million project to drastically lower water levels and kill off fish to improve water quality and restore waterfowl habitat. The lake has historically been a waterfowl mecca, but persistent high water degraded the lake and spawned a burgeoning fishery.

Then late last winter, a natural winter kill — spurred by cold temperatures that produced 3 feet of ice and low oxygen levels — wiped out many of the lake's fish. That gave the DNR's project an unintended boost, though it brought an abrupt end to some spectacular fishing.

"It was a pretty significant winter kill," Bengtson said. When the DNR saw plunging oxygen levels were going to kill many of the lake's fish, it opened the lake to unlimited harvesting for 10 days last March.

Lots of anglers showed up. Successful ones used chain saws to saw large holes in the ice, and scores of oxygen-starved fish congregated in the holes and were netted.

"It only lasted a few days, and then it was over," Bengtson said. "The fishermen I talked to were amazed. Most people had never experienced anything like that. It was an eye-opening experience."

Later in May, after the ice disappeared, the remnants of some fish washed ashore.

"We found some really large bass and northerns, but a lot of panfish just went to the bottom of the lake," Bengtson said.

DNR test-netting showed a few northerns and some tiny crappies survived but no bluegills, Bengtson said. More importantly, he believes bullheads also took a major hit, though some likely survived. They root up sediment, causing turbidity and killing vegetation. The absence of all the fish allowed the flourishing of invertebrates, which feed on the lake's overabundant algae.

Water clarity immediately improved, which allowed submerged vegetation to grow.

"The water clarity this year is the best I've ever seen," Bengtson said. "The water used to be pea-green in July. Now you can easily see down 6 to 8 feet."

The remaining fish might have short lives.

Using a new water-control structure engineered by Ducks Unlimited (DU) and installed last year, officials lowered the water level by 4 inches before the lake froze. The drawdown will resume this spring, and the DNR hopes to eventually lower the lake by 4 feet. When a pumping station is added this summer, the lake will be drawn down even further, all but draining it to kill the last of the fish, expose mud flats and generate new vegetation.

Then the lake will be allowed to refill to an average of 3 to 5 feet. In recent years, its average depth has been 7 to 9 feet, with some spots as deep at 12 feet.

All of this will take time, because water has to be released slowly to keep downstream areas from flooding. Draining a big lake isn't like draining a bathtub.

"It may take three to five years, depending on how much precipitation we get," Bengtson said. The pumps will be turned on for major drawdowns every 10 to 15 years, to revitalize the lake.

"The goal is to improve water quality by managing water levels to historic lower levels," he said. "There will be better habitat for waterfowl and other wildlife. It's a very important diver duck lake."

The lower water levels will spur more natural fish kill-offs, which will help maintain high water quality. The project was funded by the Outdoor Heritage Fund.

Meanwhile, the improved water clarity and vegetation should have been attractive to ducks last fall. But waterfowl hunting there was only so-so, Bengtson said.

"I didn't get the impression there was a large buildup of waterfowl," he said. "There were a lot of curious hunters who wanted to see what had happened to the lake. And there was some good diver hunting in mid-October."

Bengtson said he believes hunting will improve as water levels are lowered, boosting the attractiveness of the lake to ducks.

"It will get better," he said. "It will just take some time."

Doug Smith • dsmith@startribune.com