“STREAMBANK RESTORATION” IN THE PACIFIC NORTHWEST: THE USE OF NONTRADITIONAL METHODS TO STABILIZE ERODING BANKS

Traditional bank stabilization methods, such as riprap and other non-deformable bank lining, have become increasing difficult to implement in Pacific Northwest streams. This is an outgrowth of (1) increasing public awareness of ecosystem functions, (2) funding sources that prioritize stream restoration over channel stabilization, and (3) regulatory constraints resulting from aquatic species protected by the federal Endangered Species Act. Because of the negative connotation that has developed regionally around the term “bank stabilization”, these projects are now labeled categorically as “streambank restoration.” While perhaps a kinder and gentler way of saying bank stabilization, the underlying principles and processes remain the same.

Because traditional stabilization measures have become untenable in both regulatory and funding frameworks in the Pacific Northwest, practitioners have been forced to become more creative in both their material selection and design approaches. As an example, traditional rock revetments are commonly being replaced with engineered structures which integrate large wood, gravel ballast, and rebar pinning. In contrast, new channel stabilization projects that primarily utilize rock, concrete, and gabion baskets have become almost nonexistent. Through the use of case studies, this talk will highlight new and emerging technologies in streambank stabilization that seek to reduce bank erosion while concurrently providing aquatic and riparian habitat benefits. Additionally, the relative success rates of these approaches will be compared to more traditional engineering methods.