EXPERIENCE WITH MOVABLE BED TIDAL MODELS

Abstract

A particular problem, of those arising in the economic development of estuary regions, concerns the maintenance and enlargement of navigation channels. The sediment transport plays an important role in connection with this problem. .Though the hydrodynamical processes are today, with the help of mathematical procedures, fairly exactly grasped, there is still insufficient knowledge about the related transport processes, the formation of ripples and dunes and of longterm periodical morphological changes. Nevertheless, the engineer wants information about sediment transport for his planning. A well-known aid is the movable bed hydraulic model, which has been technically developed to simulate the natural fluid-sediment interaction. Such models are not yet standard in hydraulic research institutes and. furthermore, they are not easy to handle. This is probably due to a lack of suitable similarity criteria for insuring valid experimental results. However, there exist recently developed somewhat compromised similarity relationships, which can be used for distorted movable bed tidal models. The experience gained with the movable bed. model Elbe I at the Bundesanstalt fur Wasserbau (BAW) in Hamburg provides an incentive for investigating special cases in other large tidal models of the German North-Sea coast. These models are presented in Fig. 1.