Salmon Creek Bridges Battle Ground, Washington
All three bridges on Salmon Creek south of Battle Ground in Clark County were categorized as scour critical. Installation of subgrade riprap as a scour countermeasure would be required as part of repairs and a self-mitigating design.
Scour Repairs Meet Mitigation Planning
In addition to scour repairs and the associated permitting, the Salmon Creek Bridges required substructure repair. Improvements to Lehto Bridge would also include new soil nail wingwalls. The permitting approach involved design of subgrade riprap to not adversely affect fish habitat and the inclusion of channel grading that maintains no-rise of the regulated floodplain. Additionally, creative identification of existing issues, including derelict riprap at the streambed surface, allowed the project to be considered self-mitigating and not require off-site mitigation. The Otak team led the design and permitting in repairing these structures while protecting local habitats.