HYDRO- AND MORPHO-DYNAMICS AT RIVER ENTRANCES

A mathematical model for calculating river mouth morphology change is overviewed, in which longshore sediment intrusion into a mouth by waves, as well as sediment flushing out of a mouth by river and tidal discharge is considered. Behavior of an analytical solution is discussed for various combinations of opposing forces acting at a river mouth. For model verification, as well as for planning, management and serving as the information for the engineering projects in a river mouth area, in-situ monitoring of morphology changes is important and inevitable. Thus, recent monitoring method of river mouth morphology is also introduced, which enables us to make an accurate and frequent survey of river mouth. Furthermore, quantitative discussion will be made for wave set-up, water level rise due to wave breaking, in a river entrance.