Studies were made to determine the erosive effect of gravity water waves on earth material obtained from the Kennewick Main Canal, Yakima Project, Washington. The soil is classified as a fine silt having practically no cohesive qualities. Three placements of the soil were made in a side-slope test section of a canal represented in a wave flume. Each placement received the same kind and degree of compaction but was subjected to the action of a different wave produced by a wave generator. The amount of bank erosion was measured and the relationship of the volume of eroded soil was determined with respect to wave length, wave period, wave height, and the time of exposure to waves. (Author).