COMPARATIVE STUDY ON THE SEDIMENT TRANSPORT MEASUREMENT CHARACTERISTICS OF PIPE TYPE AND PLATE TYPE HYDROPHONES

Abstract

 Sediment transport monitoring in mountainous regions is useful for integrated sediment management in sediment routing system and planning countermeasures for reservoir sedimentation problems. Recent monitoring devices including a hydrophone and a turbidity meter have successfully applied as indirect sediment transport monitoring techniques. Conventional hydrophone is made of a steel pipe, and in a mountain stream with heavy sediment run-off, the pipe is easily damaged by gravel or stone impacts, and it is often the case that reliable data can not be obtained for long-term observation. Therefore, some of the devices today employ a steel plate instead of a steel pipe, so that this works against a high-impact collision. The use of the steel plate type devices, however, are still in a study phase because the nature of their data and methods to convert their outputs to bedload transport rate are yet unclarified. This study aims to compare behaviors of the pipe type and plate type hydrophones by analyzing field experimental and real observation data by both devices installed in the same location, and to discuss applicability of the method to calculate bedload transport rate developed for the pipe type device, to the data obtained by the plate type one.