The Hennepin County Board approved another $100 million Thursday to cover cost overruns for the Southwest light rail line.

The latest expenditure would bring the county's contribution to nearly $1 billion. The estimated cost of the 14.5 mile line from downtown Minneapolis to Eden Prairie is about $2.7 billion.

The board voted 6-1 to approve the additional funding, with only Commissioner Kevin Anderson voting against it. With the state sitting on a $17 billion surplus and the county having many transportation needs, he said he couldn't support the funding.

"It's not a lack of support for transportation projects," he said. "There needs to be a statewide investment."

During the meeting, the board also approved a $2.61 billion budget for 2023, which includes a net property tax levy of $930.8 million. This is a 3.5 percent property tax levy increase from 2022. The board has initially proposed a 4.5 percent levy.

The county will fund the $100 million from its half-cent transportation sales tax. Several commissioners guaranteed it wouldn't prevent or take away money from any projects.

The county's contribution is contingent on the full Metropolitan Council's approval next week of an additional $111 million for the project, which was unanimously recommended by the council's transportation and management committees meeting earlier this week. The majority Met Council portion would be funded by federal COVID-19 relief money.

Even with the new funding, the project will need several hundred million dollars more to complete. The Southwest line is more than 60% complete, with some $1.8 billion spent to date, and is expected to begin service in 2027 — at least nine years behind schedule. About $2 billion of the project is being funded by the Federal Transit Administration and Hennepin County,

The state's Office of the Legislative Auditor, a nonpartisan watchdog agency, plans to issue the first part of a special review in February about the series of cost overruns and a dwindling contingency fund to cover unexpected construction costs. Many of new construction expenses have been caused by construction of a tunnel in the Kenilworth Corridor in Minneapolis, and a crash wall separating light rail and freight trains west of Target Field.

Commissioner Jeff Lunde justified the county's continued financial support of the Southwest light rail because it is consistent with transportation and climate control goals. He said the talk he hears of scrapping the project is fiscally stupid.

"We would have to pay back a billion dollars in federal funding we have received and would lose all the money we've already spent," he said. "And then we would get stuck with the bill for cleaning up what has already been built."

He added that lessons learned from Southwest can be used in the development of the Blue Line extension from Target Field station to Brooklyn Park.