Open channel velocity profiles over a zone of rapid infiltration

Laboratory measurements have been made of the modification of the velocity profile in an open channel caused by a region of rapid infiltration through the bed, such as that associated with a bed-type river intake. The results have been analysed to provide an estimate of bed shear stress in the suction zone. The measurements were obtained using Laser-Doppler anemometry, and are compared with hot-wire measurements over a similar zone of suction in a wind tunnel.