Plans to replace a bridge at McDowell Grove this year could require the monthslong closure of a regional trail through the forest preserve near Naperville.
Forest preserve officials say a new bridge is needed to replace the 1940s-era, one-lane structure that spans the West Branch of the DuPage River at the entrance to McDowell Grove.
They said the existing bridge -- used by both pedestrians and vehicles -- is "critically deficient." In late 2014, an inspection found deterioration of the bridge's deck beams significant enough to reduce the structure's load rating to 5 tons.
"Being over 60 years old, it is at the end of its useful life," said Kevin Horsfall, manager of planning.
So the district is planning a $2 million bridge replacement project that could start as early as May.
The construction likely will affect trail users.
The West Branch DuPage River Trail -- a 23-mile regional path that begins in Hanover Park and runs south through DuPage -- passes directly through the construction site. That will pose a safety risk, officials said.
"We will need that area, due to limited space within the preserve, for the contractor to stage equipment," Horsfall said. "There's going to be a large crane involved. In the best interest of public safety, that area needs to be isolated and closed off."
Staff members are recommending the regional trail be closed from north of the project site to at least south of the parking lot, which will be closed.
If forest preserve commissioners agree, that part of the trail would be closed for the project's duration.
Construction is expected to take roughly five months.
The forest preserve is working with Naperville to establish a detour for the regional trail. Currently, the proposed detour route is 6.8 miles.
Meanwhile, district officials say replacing the bridge will solve numerous issues. For example, one concern with the bridge is that the road leading from Raymond Drive has a steep grade and an S-curve.
The new bridge will have two lanes for vehicles and a separate elevated 10-foot-wide path for pedestrians and cyclists. As part of the work, the entrance road that leads to the bridge will be realigned.