R.W.M.R.J.B. Ranasinghe

Morphological developments after a beach and shoreface nourishment at Vlugtenburg beach

Typically a beach is out of equilibrium after a nourishment is installed. To observe how a nourished beach behaves on the timescale of storms a monitoring campaign was set up at Vlugtenburg beach after a nourishment in the spring of 2009. Here we show a sediment budget analysis of the first 2.5 years for a coastal domain spanning 1750 m alongshore from -9 to +5 m NAP. To investigate the redistribution of nourished sand different sections of the profile are examined. Observations show that the initial response (first 6 to 12 months after construction) is large where the sediment eroded from the beach is transported offshore to form a subtidal bar. In the following period (until present) the losses in the domain are on the order of 40 m3 per m alongshore per year. These losses are concentrated in the profile around the waterline.

Dune development and aeolian transport along the Holland coast

This paper presents an analysis of annual to decadal dune behavior along the Holland Coast. In the database of the JAarlijkse KUStmeting (JARKUS) a very large collection of yearly measured profiles is available for analysis. These measured profiles are used to extract a selection of parameters relevant to the development of dunes which are inter-comparable in time and between profiles. Special attention is given to dune volume changes and parameters which could influence aeolian transport such as the beach slope and annual wind conditions. It is found that the beach slope is significantly correlated with dune volume changes on an annual timescale. No temporal lag between the two parameters is found. Additionally, annual wind conditions are found not to correlate with dune volume changes; windy years do not show different dune volume changes than relatively quiet years. The results of this analysis provides new insight on processes governing aeolian transport and how to model aeolian transport and dune development. Extending the analysis to more areas along the Dutch coast could give more information on specific processes regarding dune behavior.