TO REBUILD AND REORIENT an elevated section of the Massachusetts Turnpike near Boston University, the state Department of Transportation is currently planning to build a temporary Soldiers Field Road bypass out over the Charles River about 50 feet offshore, which would require filling in parts of the river where the bypass connects to land.

The proposed  bypass would break off from the existing section of Soldiers Field Road about 330 feet west of the BU Bridge, rise on fill to a temporary bridge several feet off the water, and then return to the shore further west down the river. The bridge, along with a pedestrian path, would be about 50 feet offshore and be about 80 feet wide, reducing the width of the Charles River in that section from 500 to 370 feet.

State transportation officials say the decision to run the road out over the Charles River was dictated by the need for construction space as the Turnpike is lowered to ground level in that area; Soldiers Field Road is elevated over the Turnpike; rail lines are reconfigured; and sewer, water, and utility pipes are relocated. The whole process is expected to take nearly a decade to complete.

Mike O’Dowd, the state transportation official in charge of the project, said in October that the proposal to build the Soldiers Field Road bypass out over the Charles had been generally well received, a comment that spurred immediate pushback from some advocates for the river.

An artist rendering of the completed and reconfigured elevated Soldier’s Field Road and pedestrian path along the Charles River. (Source: Massachusetts Department of Transportation)

At a joint meeting Monday of the boards overseeing the Massachusetts Department of Transportation and the MBTA, Transportation Secretary Stephanie Pollack suggested the state has little choice but to build out over the Charles River. A presentation to the boards said the bridge out over the Charles is needed if the state is going to do the construction work and retain throughout the project six Turnpike lanes, four Soldiers Field Road lanes, a pedestrian path, and two operational commuter rail lines “for as long as possible.”

Pollack said the new design for the road and rail system in that area will serve the region well once it is completed. One of the big improvements will be a better designed bank along the Charles River and more green space. Indeed, O’Dowd said, the park land along the river will be expanded by several acres and feature separate bike and pedestrian pathways.

But Pollack warned that the long-term benefits won’t be achieved without some significant pain during the 10-year construction period. “It is really hard to build,” she said of the project.

Pollack also suggested some of the criticism of locating a Soldiers Field Road bypass in the Charles River had been overblown. “It is a bit of an exaggeration to call this a middle river highway,” she said, without identifying who referred to the road that way.