Eroding shoreline bluffs, or feeder bluffs, are a recurring dynamic geologic process that can be found along Whatcom County’s marine shorelines. Bluffs provide materials necessary for forming and maintaining our beaches, as well as supporting the geologic, biologic, and aesthetic diversity of our shorelines.

Many bluffs are naturally unstable due to soil, slope, and water conditions and are subject to periodic erosion, sliding and slumping. The natural rate of bluff erosion on Whatcom County shorelines varies and depends on several factors, including: exposure to wave action (toe erosion and undercutting), geologic resistance to erosion, and the width and elevation of the beach below.
Sand, gravel, and other materials that come from the erosion of these bluffs nourish nearby beaches, spits, and other types of accretion shoreforms. Protection of the natural function of these sources of beach material is vital for the long-term stability of shoreline habitat and process.

Management Concerns
Risk of more frequent or more intense bluff erosion and slides can be aggravated by increased development and human activities. Activities that can have potential impacts include: increased or focused drainage concentrations such as stormwater runoff or septic drain fields, removal of trees and vegetation, road cuts, excavation, placement of fill materials on a slope face, and so on.

Periodic efforts to control erosion and stabilize shoreline bluffs to protect developing shoreline areas are complicated by the fact that most of the marine beaches in Whatcom County consist of materials contributed by erosion of feeder bluffs. Not only can these efforts have significant financial impacts, but they can also lead to significant environmental impacts.

Prevention of erosion and landsliding in some areas may actually result in considerable declines in sediment supplies that continually replenish our beaches. A reduction in materials can essentially starve beaches and downshore areas, leading to the loss of beaches, fish and wildlife habitat, and accelerate erosion of previously stable areas.