This report is the second in a series of reports detailing the procedures used and the results obtained from studies designed to determine the impacts of erosion control structures on habitat at Willapa Bay, Washington. The erosion control structure, consisting of a 1600-ft rock groin and an attached 930-ft underwater dike was placed on Washaway Beach in 1998 to protect State Route 105 from erosion. The location and general layout of the area surrounding the rock groin is locally known as "Jacobson's Jetty." The objectives of the study are to develop an understanding about whether groin-type structures on the outer coast can alter migratory movement or predation pressure on juvenile and adult salmon. The Washaway Beach dike and groin structure is an example of such a feature and provides an opportunity to conduct coupled studies on the physics and associated ecology of these sructures in this environment.