Study of flow structure and sediment entry to a lateral intake

This paper reports on a set of laboratory experiments involving a layout that is common in irrigation diversion works. The layout involves a lateral intake channel with a diversion dam, positioned to allow the flow to be controlled and managed. Based on experimental measurements and observations, the effect of diversion angle (ranging from 90 to 120°) on the structure of the approaching flow to the lateral intake and amount of sediment entering the intake was investigated. Velocity fields both upstream of the intake in the main channel and in front of the intake in the sluiceway were measured under various discharge combinations of the river, intake and sluice gate. Analysis of sediment measurements showed that the intake with a diversion angle of 110° had the least amount of sediment entering the intake. Analysis of the streamlines in the main channel showed that the width of the bottom-diverted current in the main channel decreased as the diversion angle increased. Furthermore, analysis of the data showed that the product of the width of the diverted current and the mean shear stress decreased when the diversion angle increased from 90 to 110° before increasing again at 120°.