The application of geostatistics in defining the characteristic distance for grain size trend analysis

Sediment trend analysis is a widely used tool in coastal management. The Gao and Collins method is used mostly in complex open marine environments. A key component of this method is the notion of a characteristic distance known as Dcr. Geostatistics are used to improve the determination of this parameter. A new distance called Dg is proposed through the analysis of the semi-variogram. A comparison between Dcr and Dg was performed by numerous tests upon regular/irregular and filtered/non-filtered sets of sedimentological data. Compared to tracer results, regular and non-filtered data are considered to be the best descriptor for sediment trend patterns. Using 260 sedimentological samples from the southern Bay of Seine (English Channel), an application of this approach allows us to gain a better understanding of the superficial sediment transport pathways between the Seine estuary and narrow shallow water area north of the Calvados coast.