Boat-Wave-Induced Bank Erosion on the Kenai River, Alaska

Abstract : The Kenaitze Indian Tribe requested that the U.S. Army Engineer Research and Development Center (ERDC) determine the relative contribution of boat-wake-induced bank erosion to total bank erosion along the Kenai River. The approach used in this study consisted of a delineation of boat wave characteristics along the study reach and a geomorphic and bank stability assessment. This analysis showed that, at specific times of the year and at specific locations, boat wave energy may be a dominant factor. However, on an average annual basis, boat wave energy is secondary to river currents in terms of total bankline recession. Reduction of boat wave energy should focus on areas having large boat passage frequency, such as the drift area at river miles 10 12 and areas where bank erosion is most problematic.