DYNAMIC SANDBAR FLUSHING & REFORMATION MECHANISMS AND RIVERBED MANAGEMENT AT ESTUARY AREA OF THE SAGAMI RIVER

Abstract

 Hydro-morphological processes are complex in the river estuary area, since certain intensity of a flood induces sandbar flushing under fluvial systems and subsequent reformation occurs due to coastal waves, and they are processed in a short period and repeated by each flood. Therefore, it is important to establish a methodology in order to both efficiently and effectively manage riverbed at the estuary area under the dynamic complexity. This study revealed this dynamic sediment mechanisms and discussed a methodology for estuary riverbed management in the Sagami River, Japan. Firstly, dynamic processes of the sandbars are analyzed. We used 3D geomorphic survey data and numerical simulations, in order to develop 3D geomorphic data. Secondly, several geomorphic features of the sandbar are set and analyzed in combination of dredging width and flood intensity. Further, reformation processes were numerically analyzed for desirable geomorphic features of the sandbar.