Design of irrigation drop structures

The approach channel and flow characteristics throughout the length of the drop structures were reviewed on the basis of open channel hydraulics. Many useful proposed stilling basins were also introduced and compared with each other in terms of both length and performance. Two types of drop structures were primarily investigated: first, a vertical drop structure with abrupt fall; and second, an inclined drop structure with a stilling basin. Figures have been prepared which may be used to: (1) determine drop structure dimensions for design purposes; and (2) as a guide in analyzing or predicting the flow characteristics under given conditions. By expressing step-by-step design procedures utilizing figures and suitable parameters as outlined in this study, the computation work is greatly simplified. In addition, generalized design procedures provide sufficient flexibility to adopt various types of structures to a wide variety of problems.