This monograph generalizes the design of stilling basins, energy dissipators of several kinds and associated appurtenances. General design rules are presented so that the necessary dimensions for a particular structure may be easily and quickly determined, and the selected values checked by others without the need for exceptional judgment or extensive previous experience. Proper use of the material in this monograph will eliminate the need for hydraulic model tests on many individual structures, particularly the smaller ones. Designs of structures obtained by following the recommendations presented here will be conservative in that they will provide a desirable factor of safety. However, model studies will still prove beneficial to reduce structure sizes further, to account for nonsymmetrical conditions of approach or getaway, or to evaluate other unusual conditions not described herein. In most instances design rules and procedures are clearly stated in simple terms and limits are fixed in a definite range. However, it is occasionally necessary to set procedures and limits in broader terms, making it necessary that the accompanying text be carefully read. At the end of this monograph is a graphic summary, giving some of the essential material covered, and a nomograph which may be used as a computation aid. These sheets are particularly useful when making preliminary or rough estimates of basin sizes and dimensions.