Effects of Tide and River Discharge on Mud Transport on Intertidal Flat

Abstract

Fine-grained sediment budgets based on the monthly bed level and net sediment flux monitoring from October 2006 to October 2007 are estimated to examine the relative contributions of tides and river discharge to mud transport on an intertidal flat adjacent to a river mouth in a semiclosed sound. The estimated sediment budgets are interpreted using the water mass balance equation and the horizontal tidal current pattern measured using high frequency (HF) radar. The intertidal flat accreted during normal discharge conditions are primarily attributable to the alongshore sediment flux toward the river mouth. However, the flat was eroded when the large offshore suspended sediment transport occurred on the flat during the large river discharge. The net alongshore tidal current causes alongshore sediment fluxes toward the river mouth on this intertidal flat adjacent to the river mouth. These findings may be specific to this site, but an adopted comprehensive approach may be applicable to other sites.