Kustlijnzorg Project : statistical modelling of the impact of nourishments on thebeach and dune systems

A stochastic model has been developed, based on the historical trend analysis of long-term yearlyrecorded Jarkus-data, in order to describe the long-term dynamics of Coastal State Indicators (e.g. MCL position). The model includes mathematical representations of the most relevant phenomena: long-term trend, influence of nearshore bar dynamics and impact of nourishments. The stochastic model appears to be a useful tool to describe mathematically the impact of nourishments on the long-term trend of Coastal State Indicators, highlighting either a regressive (in time) behaviour of the transfer function representing the impact, that is consistent with the sawtooth concept, or a retentional or progressive (in time) behaviour of the transfer function (blocking mechanism in combination with longshore transport). The description of the actual state of the system, or so-called Testing Coastline (TCL), would be performed with more insight on the structural developments, using the stochastic model. Moreover, its application would lead to an indication for the (expected) coastal state in the years T to T+10. Finally, after defining the model parameters for a specific site, the model could be used as a predictive tool, to study the impact of nourishment design alternatives, and therefore support the optimal design of nourishments.