EROSION AND AVULSION HAZARD MAPPING OF THE NOOKSACK RIVER

The purpose of mapping the erosion and avulsion hazards of the Nooksack River was necessitated by both riverine hazard planning through the Comprehensive Flood Hazard Management Plan and recent updating of the Shoreline Master Plan and Critical Areas Ordinance. This fundamental geomorphic information also provides an essential tool for habitat restoration planning under a recently adopted federal recovery plan for two salmonid species native to the Nooksack River. The intent of the mapping effort is to provide a technical background document and set of maps to help guide decision makers in developing comprehensive flood hazard and ecological planning. The combination of the historic, erosion and avulsion hazard mapping are the foundation for delineating Channel Migration Zones (CMZ) (Rapp et al, 2003). Modern datasets and assessment tools, such as GIS, LiDAR, digitized orthophotographs and historical surveys, and GPS have added to the data available to help understand river morphology patterns used to delineate riverine hazards. Combined, these provide analytical tools that can provide policy-makers and the public with the key analyses they will need to guide and regulate public safety, private landownership, and public resource and restoration issues related to river management.