Maintenance dredging in a macrotidal estuary: Modelling and assessment of its variability with hydro-meteorological forcing

This study used a hydrodynamic and sediment transport process-based model to simulate maintenance dredging in macrotidal estuary: the Seine Estuary. sandy-muddy estuary allows access two major ports (Le Havre Rouen). The accounts for sand mud dynamics was previously validated turbidity morphodynamic coupling. Dredging is schematised as physical process responding simulated seabed evolutions. In coherence with port practices, (i) numerical conducted when depositions exceed nautical depth limits determined by authorities; (ii) dredged are released water column above dumping sites. successfully reproduced amount of harbors fairways (7MT/year) without any drift along 10 years. Moreover, quantities appeared be considerably higher than estuarine maximum (ETM) mass, which model. relationships between requirements hydro-meteorological forcings. related forcings different ways depending on exposure areas waves, currents ETM. Le harbor fairway sensitive storms, 75% activity due waves 1m. entrance Rouen equally responds tidal range, river discharge waves. Variabilities differ type sediment. For instance, at navigation channel, strongly correlated range secondarily discharge, while dominantly A specific simulation (not including local wind-induced circulation) showed that low contribution explained materials suspension hauled off-site. induced westerly winds occurred together On other hand, increases amplitude intense currents, presents counter clock-wise hysteresis amplitude, can compared one followed ETM mass. addition, dependence appears proximity ETM, main source fine sediment, location shifts downwards increases. At an inter-annual scale, variability temporal distribution hydrometeorological leads 50% variation annual masses. conclusion, this has improved understanding responsible dredging. • Maintenance estuary. differently. needs increase resuspension either or currents. Mud presence maximum. Sand varies because bottom circulation.