Lateral Flow Exchange in Transient Compound Channel Flow

Abstract

Lateral flow exchange takes place between the main channel and the flood plain during the movement of a flood in a compound channel. An estimate of this lateral flow exchange is necessary in the application of transient one-dimensional coupled flow compound channel models. Two simplified theoretical equations are derived for flow exchange between the main channel and the flood plain in terms of the local channel and flood plain flow depths for fully and partially flooded flood plains with zero lateral slope. Data from numerical experiments support the trend of these equations reasonably well and empirical regression equations are proposed for practical purposes.