Integrating flood mitigation, sediment management and habitat enhancement on coastal rivers of British Columbia

Abstract

This paper describes the challenges of reconciling flood mitigation, sediment management and aquatic habitat preservation on two rivers in British Columbia: the Vedder River in the lower Fraser Valley and the Cowichan River on Vancouver Island. Both rivers were channelized and modified greatly at the turn of the last century and were diked to protect rapidly growing communities against flooding. Both support important salmon stocks but have experienced habitat loss due to past flood control works. The lower reaches of the rivers are alluvial fans and are subject to gravel aggradation and avulsion hazards. River management on these systems involves mitigating flood risks on stream channels that are subject to aggradation and sediment deposition while preserving or enhancing aquatic habitat. © 2013 WIT Press.