Bundle 508 Stormwater Designs (OR)
The existing I-5 and OR 126 bridges are located in central western Oregon, with three bridges along Interstate 5 (I-5) south of Eugene and four bridges on Oregon 126 west of Eugene. The I-5 bridges are located between milepost (MP) 154 and 164 at the Elkhead Road, Curtis Creek, and Bear Creek crossings. The southernmost bridge, Elkhead Road, is located approximately 22 miles south of Cottage Grove. The Oregon 126 bridges are located between Mapleton and Eugene with the westernmost bridge, Knowles Creek, located 4 miles east of Mapleton. Five of the seven bridges will be fully replaced, one bridge will be a partial replacement and repair, and one bridge will be a repair only project.

WEST Consultants performed the stormwater designs, hydraulic designs, geomorphic analyses, and scour evaluations to support the bridge replacement designs. The bridge and stormwater designs were required to meet ODOT’s Environmental Performance Standards (EPS) in order to utilize ODOT’s programmatic permit for the bridge replacement program. Additionally, an agreement between ODOT and the regulatory agencies resulted in stormwater facility designs that will provide treatment for as much of the contributing impervious area (CIA) as practicable. This was a compromise reached after cost estimates for construction of the facilities necessary to provide full treatment of runoff from the CIA exceeded available funding.