Construction can soon begin on a major tunnel meant to provide flood relief to the Baylor University Medical Center area and other parts of the city.

The Dallas City Council on Wednesday unanimously awarded the $206.7 million contract to Southland Mole, a Roanoke-based joint venture. The vote ends a two-year saga surrounding the bidding process. The contract was the big-ticket item from the $642 million 2012 bond package.

"It has taken a long time," said Mayor Mike Rawlings. "We are going to start the flood prevention process in East Dallas."

The five-mile-long tunnel, which will be 30 feet in diameter, is designed to provide 100-year flood protection to the areas around State-Thomas and Woodall Rodgers, East Dallas, Fair Park and south of Buckner Park. The tunnel will be built, with the help of a boring machine, about 70 to 100 feet under the surface.

The water levels on the streets in those areas tend to rise with any sustained heavy rains. Storm sewers in the increasingly dense neighborhoods were built in the 1930s. The city has reported significant flooding in many of the areas in 1995, 2006, 2007, 2009, 2012 and 2015.

Kristi Sherrill Hoyl, chief policy and community officer at Baylor Scott & White Health, said in a written statement that she is "very supportive" of the project.

"It is critical that vital infrastructure like the Level I Trauma Center and emergency department at Baylor University Medical Center are protected from floodwaters and can stay open to take care of patients," she said.

Dallas Area Rapid Transit, which has several train stations in the area, could also benefit. Agency spokesman Morgan Lyons said DART has had "flooding issues in the area before, so we're hopeful this will help address it."

Dallas voters approved money in the 2006 and 2012 bond packages for the project. In total, it is projected to cost taxpayers $275.7 million, barring any change orders later for construction, engineering, design and other needs.

The projected construction cost is actually a few million dollars less than it would've been if the council had approved it in 2016. Tim Winn, a partner with Southland Mole, said the company's bid came in lower this time because it found a way to recycle the rock it pulls from underneath the city.

Southland Mole, a company affiliated with longtime city contractor Oscar Renda Contracting, won the competitive bidding process last time, too. But myriad issues with the bidding process — as well as a subcontract with a man convicted in the sprawling corruption case that brought down former Mayor Pro Tem Don Hill — caused the council concern.

Ultimately, the issues — which were raised by disqualified bidder Odebrecht Construction and City Auditor Craig Kinton — prompted the council to reject the bids and call for a do-over.

This time, Kinton's office worked with Trinity Watershed Management, which tweaked some of the project, during the process to sort out any issues. Odebrecht did not submit a new bid. The company's giant Brazilian parent has been embroiled in a corruption scandal in Brazil.

But Michels Tunneling, which had a second-place, $224.8 million bid, submitted a protest, saying the Southland Mole bid was unbalanced. The city rejected the protest, saying it was unsubstantiated. Winn said he was not surprised that one of the two other bidders protested.

"In the tunnel world, that happens on every single job," Winn said.

Council members on Wednesday said they were pleased with the bidding process this time around, and some hoped that it would be a model in the future for other large contracts.

Casey Thomas and Tennell Atkins, who represent the southernmost parts of Dallas, questioned whether minority subcontractors would be part of the deal — more than a quarter of the cost will go to minority- and women-owned businesses — and came away satisfied.

Lee Kleinman, who chairs the committee that oversees flood-related infrastructure, said he appreciated the collaboration between the city auditor and other city officials. Philip Kingston, whose district includes a sizable chunk of the project, said the process was "sleeker and more reliable" this time.

But Kingston implored the city to come up with a "bad actors list" of people who should be barred from doing business with city taxpayer money in the future. And he called the original bid process "one of the worst-run procurements ever done in the city of Dallas."

Far North Dallas council member Sandy Greyson disagreed and said the 2016 dispute was "one of the most inappropriate protests" she had ever seen on a contract.

She echoed her comments from a committee briefing that the city got "really lucky and it came in a few million dollars less."

Trinity Watershed Management Director Sarah Standifer said the project will kick off at the end of February and construction will begin in March. Construction is scheduled to take about five years, and the tunnel is slated to open in December 2022.