The contribution of aeolian and marine processes to decadal coastal dune evolution along the Dutch coast.

The development of coastal dune systems is determined by the balance between aeolian and marine processes acting on the system. Traditionally, aeolian processes have been considered as constructive and marine processes as destructive with respect to dune evolution. However, a recent study has shown that marine processes can also contribute to dune build-up (Cohn et al., 2018).

In our study, a unique data set from the Dutch coast is analyzed to investigate the relative importance of marine and aeolian transport processes on decadal-scale dune evolution. The Jarkus data set contains cross-shore elevation profiles that have been measured yearly since 1965, spaced 200-250 m apart along the entire, 200km long Dutch coast. Previously, the Jarkus dataset has been used to study temporal variations in dune behaviour related to, e.g., beach width (De Vries et al., 2011), nourishments (Bochev-van der Burgh et al., 2009), wind conditions and beach slope (De Vries et al., 2012). These studies mainly focussed on the temporal variations in dune volume changes. However, in our study, we explore to what extent temporal variations in environmental factors, like foredune slope and storminess, explain temporal and spatial variations in dune evolution.

The results show for example that where dune volume growth rates seem constant in time, the growth of secondary dune ridges can be reduced due to the initiation and development of a new primary foredune depending on marine and aeolian processes.