Sedimentation in lateral diversions causes many problems such as reduction of system delivery efficiency and increasing of maintenance costs. There are several methods for sediment control in lateral diversions and suitable means are required to reduce these difficulties. An effective method for preventing sediment deposition at entrance of diversions is submerged vanes. When submerged vanes are used, the sediment entering into the diversion is eliminated for the range of qr (specific discharge ratio which is defined as ratio of diversion unit discharge to main channel unit discharge) to be less than 0.2. Beyond this value, the efficiency of the vanes diminishes. The performance of the vanes can be enhanced in several ways such as by installing skimming wall and sill. In this research, Current Deflecting Wall-Sill (CDW-Sill) was used as a new way of sediment control at lateral diversion and the performance of sediment control of CDW-Sill was investigated. The results showed that the performance of the CDW-Sill, up to the available specific discharge ratio of 0.6, was better than the submerged vanes. However up to specific discharge ratio of 0.4, the width of main CDW channel equal to 14 cm had the best performance for different widths of secondary CDW channel which eliminated the sediment uptake.
