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The innards of Byllesby Dam on the Cannon River were manufactured in 1910, when the average worker earned 22 cents an hour and William Taft was president. The dam’s bearings and runners have been whirring for most of the last century, long past their recommended life span.

This year, Dakota County asked for — and got — $6 million from the Legislature to fund much-needed updates to the dam’s turbines and powerhouse. In the process, the dam’s hydropower production will nearly double, saving Dakota County taxpayers money on future dam maintenance.

Byllesby Dam has been a top-priority project for the County Board for several years. The county and the Department of Natural Resources have collectively spent $13 million in the past decade to repair its parts, mostly to satisfy federal requirements, said Josh Petersen, senior water resources engineer for Dakota County.

The rest of the dam is “up to snuff,” Petersen said, but the turbines could go at any time.

“I always use the analogy [that] it’s like driving a Model T,” Petersen said. “Anybody can go out and buy a Model T Ford if you want to. … It’s not going to be cheap and it’s not going to be efficient.”

The County Board sought $6 million in state funding last year but tabled the project when the bonding bill failed to pass.

This year, the Legislature allotted money to repair, rebuild or tear down six dams and make emergency fixes to several state-owned dams. The Byllesby project got the most money.

“We’re thrilled to death,” said Earl Benson, president of the Lake Byllesby Improvement Association. He said he’s been living on Lake Byllesby “since I was two years old and I live on the lake now.”

Benson said he’s also excited about blueprints for Lake Byllesby Regional Park. At last week’s County Board meeting, commissioners discussed a draft of the park’s master plan, which includes more camping areas, trails and trailheads and access to the Cannon River below the dam.

Not exactly green energy

Byllesby Dam is designated as a “high hazard” by the federal government because if it fails, people would likely die and property damage would be extensive.

Northern States Power (now Xcel Energy) owned it until 1969, when Goodhue and Dakota counties bought it together. In 2009, Dakota County took it over.

A recent study determined that removing the dam was too costly, would deprive residents of the power it provides and might prompt a lawsuit from property owners because of diminished values, said Petersen, the water resources engineer.

Byllesby’s new turbines will generate nearly twice the energy and cut maintenance costs. The excess power it produces can be sold, saving taxpayers money.

But dams come with “environmental baggage,” said Luther Aadland, a natural resources consultant for the DNR. They block fish migration and their reservoirs emit methane, a greenhouse gas.

“The term ‘green energy’ probably doesn’t fit real well with hydropower,” Aadland said. “I think most people are not aware of [dams’] effects.”

It will cost about $14 million to replace the turbines and revamp the powerhouse. The county will finance $8 million of that.

Erin Adler • 612-673-1781