Abstract

Sedimentation in irrigation canals is one of the important problems in the exploitation of any irrigation project. This problem has many direct and indirect effects on the hydraulic characteristics and economical considerations of canals. The main objectives of the present study were: (1) to study the influence of the transmitted sediments on the hydraulic capacity of the canals, (2) to examine the various existing theories and relationships for determining the settling and non-settling velocities in the irrigation canals, and (3) to recommend the best possible and economical solutions to avoid sedimentation process in irrigation canals. The results of the study show that the limiting concentration theory and the Kennedy method had the best agreement with the measured values, respectively. Thus, these methods can be used in the design of irrigation canals to avoid sedimentation process. Also, by regulating the water surface elevation in the canals and monitoring the concentration of the sediments in the entering water, it would be possible to create the non-settling velocity conditions in irrigation canals.

Key words: Non-settling velocity, irrigation canal, regime theory, limiting concentration theory.