Inflow Seepage Influence on Straight Alluvial Channels

Abstract

A flume study was conducted to identify and analyze the effects of inflow seepage on flow in straight alluvial open channels. The effect of inflow seepage on energy slope, water surface depth, velocity, sediment transport, scour, bed forms, and resistance to flow was investigated. The results of this investigation indicated that inflow seepage increases localized mean channel velocity, energy slope, and stream power in the zone of inflow. The water surface depth decreased for subcritical flow and remained nearly constant for supercritical flow during inflow conditions. Sediment transport was slightly increased when inflow was introduced in the bed. Inflow seepage did not appear to enhance channel scour. Inflow seepage significantly enhanced bed form transformation and the bed roughness. Inflow seepage also caused dunes to become longer, flatter, and move more erratically in the reach where inflow occurred. It was concluded that inflow seepage could significantly influence the channel hydraulics, stream power, bed form and bed roughness in the localized zone of inflow.