FLUME EXPERIMENTS TO STUDY THE DEVELOPMENT PROCESS OF SAND WAVES IN THE BACKWATER SECTION

Abstract

Flume experiments were carried out to understand the development of sand waves in response to the downstream water level and the characteristics of the longitudinal profile of the water level that may be affected by the sand waves. In addition, no-contact measurement of the riverbed below the water surface was carried out using a blue laser, and its usefulness in movable bed experiments was discussed. In the case of rise in water level, the sand waves developed in the entire channel section and the water level rose accordingly. In the case of low backwater, the riverbed waves developed and the water level rose in the same way, but there was a section downstream of the channel where the riverbed flattened without the formation of sand waves because the water level rose in the upstream section, thereby, contributing to a larger water surface gradient.