A coupled surface-subsurface model of overbank flood flow and air entrapment in a permeable floodplain

This paper presents a coupled surface-subsurface flow model which simulates flow over a permeable floodplain during a flooding event. A simple hypothetical example is used for illustrating the effects of the floodplain permeability (i.e. surface-subsurface exchange) and air entrapment in the subsurface on the surface flow characteristics. The results show that, for initially unsaturated conditions of a soil which forms a floodplain, neglecting both water and air movement in the subsurface may lead to significant errors in predicted characteristics of the surface flow during a flooding event which involves overbank flow.