DULUTH – A massive, multiyear highway interchange project has been scaled back after going $100 million over budget even before construction starts this spring, but project backers are hopeful the money can be found.

"I plan to drop a bill this session for that funding," state Rep. Liz Olson, DFL-Duluth, said last week. "[It's unlikely we can] bond for it, but that doesn't mean I should dial back my advocacy for my community."

The Twin Ports Interchange — the tangle of roads and ramps that connect Interstates 35 and 535 and Hwy. 53 in Duluth — is getting a $343 million rebuild to increase safety and address aging infrastructure.

But in November the Minnesota Department of Transportation (MnDOT) said it needed about $100 million more to complete the entire project as planned. Soil, streams and other factors drove up the costs to $442 million as the so-called "Can of Worms" earned its nickname.

"I've never seen something so complicated in my career," MnDOT Assistant District Engineer Pat Huston said at a project update last week in Duluth.

If the money doesn't come through, just the work on the interchanges that will eliminate blind merges and left-lane exits, among other improvements, will occur. Two other phases of the project have been indefinitely postponed.

The Hwy. 53 bridge that rises over Lincoln Park will not be replaced, though it will need rehabilitation work that had been put off since a new bridge was planned.

The Interstate 535 interchange at Garfield Avenue will also have to wait for the upgrades needed to accommodate oversize trucks leaving the port, such as those carrying wind turbine parts.

Lane closures on I-35 will begin this spring. Work will be substantially done by the end of 2022 with final touch-ups planned for early summer 2023.

Closures and detours around the interchange could stretch across the decade if work on the Hwy. 53 bridge and Garfield interchange is rescheduled. MnDOT also expects to start substantially repairing or entirely replacing the Blatnik Bridge between Duluth and Superior, Wis., starting in 2027.

MnDOT will continue to plan the entire Twin Ports Interchange project should more money become available to get it done in one go.

"I want to go to bat for my community and get the funds secured for it," said Olson, majority whip for the House. "But we can't piecemeal our entire transportation system. We need to have a bigger conversation around revenue and reinvesting in transportation."