The Twin Ports Interchange reconstruction project through Lincoln Park soared $100 million over budget this month, forcing planners to defer indefinitely portions of the work scheduled for 2020-23.

The $343 million project is scheduled to begin in May. Minnesota Department of Transportation figures released Monday at a regular public meeting about the project showed a $443 million price tag.

"This is what happens with every big project," Duane Hill, district engineer based in Duluth, said Monday. "You have to manage it as you go along. We thought we did a good job initially coming up with a budget for this project and what we’ve learned is that it's really hard."

Project funding is firm at $343 million, and there is currently no way to expect additional funding, sources said.

From here on out, the project will set aside work planned farther up both U.S. Highway 53 and Interstate 535 to focus solely on the Interstate 35 corridor, Pat Huston told more than 100 people gathered at Clyde Iron Works to hear about the project.

Huston, the major projects and assistant district engineer locally for MnDOT, called the project "way more complex" than anticipated, and said engineers are still learning about things such as underground lines and utilities that need to be moved, adverse soil conditions throughout the project footprint and scores of other concerns. For instance, Michigan Street through Lincoln Park will now need to be rebuilt for all of the wear and tear and outright damage it will endure throughout construction, Huston said.

"We didn't know what we didn't know," Huston said of the original engineering and budgeting processes. "There's still a lot we don't know."

To keep the project at $343 million, reconstruction of the Garfield Avenue interchange with Interstate 535 near the Blatnik Bridge will be deferred, and so will the planned rebuilding of the U.S. Highway 53 bridge through Lincoln Park.

That means the remedy to the unwieldy entrance from southbound Interstate 35 onto Highway 53 will require a new solution. Under a new bridge, entrants onto Highway 53 from southbound I-35 would have had a dedicated lane and not continued to be asked to crane their necks in order to merge into oncoming traffic. Several guests at the public meeting expressed dismay upon learning that news.

"We're still hoping to make it the same or better than it is today," Hill said. "We've got to do the engineering first."

The Twin Ports Interchange reconstruction project will replace a series of aging bridges and sections of elevated freeway known colloquially as the "can of worms." The project was expected to remove all left-hand exits and blind merges in an effort to make the interchange safer. Currently, it's the fourth-worst interchange in the state for crashes, said MnDOT, racking up fender benders for all of its oddball configurations.

Three weeks ago, the project reached 60% of its engineering completed. At that point, the primary contractors, Ames Construction, of Burnsville, Minn., and Kraemer, of Plain, Wis., updated the budgets, showing the $100 million gap, Hill said.

"In the last three weeks we've said, 'We've got to change direction,' " Hill said. "We had risk and contingency built into our budget, but there was just more things that we uncovered than (our contingencies) even covered."

The Twin Ports Interchange reconstruction project is also being done to make the interchange favorable for oversize loads coming into and out of the port. Currently, oversize trucks use city streets to avoid weight-restricted bridges located throughout the interchange. The Garfield interchange work that's being deferred would have greatly benefited oversize loads coming into and out of the port.

“The deferral is definitely disappointing, but every agency has to work within a budget, and that’s the reality facing the Twin Ports Interchange project," Duluth Seaway Port Authority Executive Director Deb DeLuca said. "This is a big, complex project and it is not surprising that unanticipated and extraordinary costs forced MnDOT to reshape the overall project budget."

Oversize cargo will have to remain on city streets, DeLuca said, but added "the good news is that many types of cargo/truck movements throughout Rice’s Point and the interchange area will still see benefits from improved fluidity through the interchange as a whole. The Twin Ports Interchange project is still an important transportation investment that is good for the port and good for the region.”

Huston ticked through several aspects of the project that were responsible for escalating costs, including:

An increasingly complex underground merging, that starts off the project in May, of Coffee Creek with Miller Creek into a giant box culvert under I-35 emptying into St. Louis Bay.

The real possibility of needing to treat contaminated water on the project at a cost of $200,000-$500,000 monthly.

Ground improvements to poor soil, using a process involving scores of cement pilings, that will allow I-35 to be brought to grade.

A need to relocate sections of BNSF rail in order to keep the rail yard operating throughout the project.

"I want to make sure everybody heard 'defer' and not delete," Huston said at the meeting, promising that the deferred elements won't be forgotten. In fact, by deferring those projects, Huston said each will require increased maintenance and inspection to aging bridge infrastructure until the eventual replacements.

Neither Huston nor Hill could say when the deferred aspects of the project would be rescheduled. MnDOT generally schedules its projects four years out from construction.