Bridge Approach Stabilization using Vegetated Crib Wall Techniques

INONOAKLIN RIVER PROJECT

Location: Edgewood, British Columbia

Client: Ministry of Transportation and Highways

Objective: The objectives were to prevent further undermining of the road prism caused by increased river erosion, and to protect the bridge infrastructure while enhancing and creating fish habitat.

The Inonoaklin River project is located upstream from the town of Edgewood in southern British Columbia. This project was implemented for the Ministry of Transportation and Highways. It involved the implementation of a vegetated crib wall at a bridge approach on the Inonoaklin River. The structure is composed of a combination of rootwad revetment and a live crib wall. In addition, the structures are intended to provide slope stability and increase fish habitat. The structure design and criteria were implemented to withstand a 1 in 100-year flood event.

Gerry Oliver of G.G. and Associates Environmental Science produced the design and implemented the structure. Terra Erosion Control Ltd. assisted with the construction, and provided and installed the live cuttings and vegetative treatment. The live material utilized on this project was "non dormant", harvested in the late summer, soaked for a period of ten days, and planted within the vadose zone. The species used were willow (Salix scouleriana), and red osier dogwood, (Cornus sericea). The site was monitored the following fall and during the summer of 2002 and 2003. Survival results were found to be excellent.