This Boise River bridge nearly failed. ACHD says a replacement is on the way

A year ago, the Eckert Road Bridge over the Boise River was close to collapse. Now, the Ada County Highway District has a preliminary set of designs for a new one — and a tentative timeline for the estimated $30 million project near Barber Park in Boise’s Southeast.

The ACHD this month unveiled plans for a pair of new bridges and roundabout on South Eckert Road with an eye toward an October 2026 groundbreaking, Senior Project Manager Stephanie Tanis told the Idaho Statesman in an interview Wednesday. Complete construction, which would happen in stages, will take between one and two years, she said.

The heart of the project is a newer, wider and sturdier concrete bridge over the Boise River. The existing span, which is set on wooden piers, predates the 1971 founding of the ACHD by decades, according to spokeswoman Rachel Bjornestad. In January, an ITD inspection found that 22 of its 48 supporting piles showed “moderate to severe decay,” she said; at the time, engineers estimated the bridge could support a maximum weight of three tons — about the weight of an F-250.

The survey prompted the emergency closure of the bridge to cars and trucks until early March while work commenced to buttress the roadway. It’s been open to traffic since and has passed regular inspections, Bjornestad said.

While the severity of the deterioration came as a surprise, ACHD was already scoping a replacement for the aging bridge, Tanis said.

“The plan was to get this project done, but we accelerated the timeline significantly with the findings that we had and the emergency closure,” Tanis said.

Boise bridge project includes bike, pedestrian improvements

Once completed, Tanis hopes the new infrastructure will shore up the river crossing, ease mounting traffic concerns, and improve safety near the busy entrance to Barber Park.

Some details — namely aesthetics — are still negotiable, Tanis said. But the final plan will almost certainly feature:

• An additional middle turning lane on bridges over the Boise River and the smaller, parallel Ridenbaugh Canal.
• A single-lane roundabout at the intersection of Eckert Road and Boise Avenue.
• A broader entrance to Barber Park.
• A wider bike and pedestrian lanes.
• An underpass linking pathways to the larger Boise Greenbelt near the city’s forthcoming Alta Harris Park.

State money will pay for the Boise River bridge portion of the project, Tanis said. While “early, early” estimates on the three-prong project put the price around $30 million, ACHD won’t know the true cost until the plan goes out to bid in 2026, she said.

Once the realigned two-pier bridge goes in, ACHD aims to work with other agencies to restore the riparian habitat, including surrounding wetlands and conservation easements.

As it stands, the ACHD plans to close the Boise River bridge and Boise Avenue intersection during construction, Tanis said. The closure will save an estimated $3 million in construction costs and trim eight months off of the build time, according to an ACHD website on the project. The detour next year is expected to mirror the 2025 closure, routing cars to the East Parkcenter Boulevard bridge.

Barber Park, a popular put in for float tubers and fisherman, will remain open throughout work, ACHD said.