Project Highlights

A storm system associated with Hurricane Anna moved across northern Vancouver Island in November 2014. During a 24-hour period between November 5thand 6th, 189 mm of rainfall was recorded at the weather station in Holberg, BC. The resulting flood water and landslide debris from this storm event washed out several bridges along the Holberg-Winter Harbour access road,including the San Josef River and Goodspeed River Bridges. Because the washed-out bridges cut off primary access to Winter Harbour and other parts of northern Vancouver Island, a rapid emergency response to repair bridges and re-establish access was required.

Kerr Wood Leidal was retained by Ministry of Transportation and Infrastructure to provide engineering design services as part of emergency response for the bridge wash outs. This included: on-site reconnaissance to review conditions and develop an emergency response strategy; a geomorphology/land hazard review of the upstream watershed to assess the potential for additional debris to damage temporary bridge crossings; emergency response design of replacement road approaches; and hydrotechnical analysis to recommend waterway opening sizes, erosion/scour protection and freeboard allowances for both temporary bridges and permanent bridges.

Through a staged approach for repair and replacement of the bridges, emergency work proceeded during the winter and spring months, which was outside typical fisheries window restrictions. Follow-up work was carried out during the summer low-flow period. The design incorporated emergency works into the permanent design so that reworking of constructed works was minimized, saving time and reducing capital costs.