Estimation of the efficiency of a silt screen using a vessel-mounted ADCP

Abstract

The behaviors of suspended sediment concentration (SSC) near a silt screen in a macrotidal coastal area was measured with associated hydrodynamic conditions by a track monitoring using a vessel-mounted acoustic Doppler sensor and SSC profiling at two fixed sites. Distinctive increase in the current speed of the upstream mid-layer, and return flow in the downstream lower layer were measured, which results from the screen effect. In the dredging period, the SSC markedly increases at the depth of the screen. The amounts of SS transported across the upstream and downstream sections of 20 m apart from the screen are comparable in the period of no dredging, while the amount across the downstream section is about 77 % of that across the upstream in the dredging period.