Payette River Eastside Drive Bridge

Creating a Safer Crossing Through Ponderosa State Park

Project Highlights

• Expanded from one lane to two
• 115-foot clear span
• Safer travel through the park
• Pier-free span design
• Upgraded overflow and drainage systems

The Challenge

Valley County needed to replace an aging, single-lane bridge over the North Fork Payette River in Ponderosa State Park, a major recreation area for visitors crossing the bridge and for kayakers and paddle boarders passing beneath it. The existing two-span structure had limited capacity and outdated safety features. What’s more, the project had to address sensitive environmental conditions, a nearby overflow crossing, and roadway drainage while meeting Federal-Aid Off-System Bridge Program requirements and Idaho Transportation Department (ITD) standards.

The Solution

Keller led the project from early planning and permitting through hydraulic analysis and final roadway and bridge design. The team designed a 115-foot, single-span bridge with precast, prestressed concrete girders, removing the need for a pier in the river, creating room for two lanes, and leaving a clear passage for paddlers. The design also considered safe access under and around the bridge and down to the river. Advanced 2D hydraulic modeling confirmed the span length and evaluated conditions in the river and overflow channel. Keller also designed a new overflow culvert and drainage improvements. The final plans met American Association of State Highway and Transportation Officials’ (AASHTO) and ITD requirements.

The Results

The new bridge gives Ponderosa State Park a two-lane crossing where there was one. Replacing the main structure and the overflow crossing addressed long-standing maintenance concerns and improved performance during river and drainage events. Drivers, paddlers, and park visitors now have a safer crossing and better access to the river.