This study has resulted in the development of criteria for the design of riprapped cantilevered pipe spillway plunge pool energy dissipators having the shape of self-formed scour holes. A literature review revealed information on the general principles of local scour at pipe exits, but inadequate practical information on scour and prevention of scour at pipe outlets. Presented herein are a research plan to provide the needed information, a description of the experimental apparatus and instrumentation, and an explanation of the experimental methods. Additional background information is a description of the scour process, and the geometry of the jet after emerging from the pipe.