A Shoreface Zonation in the Ebro Delta Based on Grain Size Distribution
Keywords:Grain size, sediment types, shoreface zones, coastal morphology, sediment transport, coastal hydrodynamics
Trends in sediments and morphology across the Ebro Delta shoreface were investigated during a three year experiment. The profile slope, the location of morphological features, the textural parameters of the sediment and the relative abundance of sand fractions were measured along the Ebro coast. The observed sediment distribution was compared with the grain size distribution calculated from simple models and with an equilibrium grain size defined from the abundance of textural fractions. On the basis of the cross-shore variations three zones were identified across the Ebro shoreface: high energy, transition and low energy zones. These zones are mainly controlled by the sediment transport processes associated with the incident wave climate. The distribution of these zones is locally disrupted by the presence of shoreface outcrops corresponding to ancient deltaic lobe deposits. The analysis of the sediment distribution is a useful tool in the definition of zones across the shoreface. Sediment distribution is complementary to other zonation criteria (based on morphology and hydrodynamics) and contributes to a better definition of the shoreface units.