Sediment control at water intakes

Abstract

Submerged vanes are shown to be effective in preventing bed load transport from entering water intakes. By generating a secondary circulation in the flow, the vanes change the magnitude and direction of the bed-shear stresses and cause a redistribution of the flow and sediment transport in the area affected by the vanes. As a result, the riverbed aggrades in one portion of the channel and degrades in another. The performance of two vane installations, designed according to guidelines developed earlier, are evaluated by comparing the bed topography before and after vanes were installed. The design guidelines, which utilize a numerical model developed earlier, are shown to be appropriate. The guidelines apply only when the intake flow is small enough that the withdrawal causes little change in the river flow velocity in front of the intake.