MODELLING A RIVER CHANNEL WITH DISTANT FLOODBANKS.

River flooding problems present a great challenge to engineers. One possible method of dealing with floods is presented in this paper, namely the use of distant floodbanks. Floodbanks are set well back from the river channel which remains undisturbed, while a significant part of the floodplain can still be used for attenuation purposes. This paper presents experimental data for a range of parameters affecting meandering channels with distant floodbanks. These include main channel roughness, floodplain roughness, main channel cross-sectional shape, aspect ratio and side slope, sinuosity, relative depth of flow on the floodplain, and effect of model scale. The paper also develops an artificial neural network, based on nine geometric and flow parameters, which is designed to predict flow discharge in a channel with distant floodbanks, whenever the flow is overbank. The paper concludes with the development of a steady-state one-dimensional numerical river model incorporating channel/floodplain interactions, which is applied to a river reach in the UK.