Flow separation from the upstream corner of the intakes is one of the major problems. This phenomenon produces a flow rotation zone in the intake, hence decreasing the flow passage and intake efficiency as a result of accumulation of sediment at the intake. During the past decades, several methods have been conducted to reduce the area of separation zone and increasing the intake efficiency. One of the methods used to increase intake efficiency is to change the hydraulic conditions by altering the intake geometry. Any method that creates a uniform velocity distribution at the intake, reduces the secondary flow, separation zone, sedimentation leading to increases in the intake efficiency. In this study, the effect of intake geometry on the sedimentation and flow pattern was investigated using the dimensions and shape of the flow separation zone. Results for three discharge ratios of 0.2, 0.4 and 0.6 showed that an optimized intake wall curvature reduced the entrance sediment by 58, 50 and 33 percents, respectively.