Title: Modelling the morphodynamic impact and the effect on significant wave height due to sand extractions.”

Date: 7-1-2016

Time: 12:30

Location: HR N109


Sand extractions are performed in the Dutch part of the North Sea in order to be able to maintain the coastal safety level of the Netherlands by means of sand nourishments. The pit that is left behind after an extraction is referred to as a sand pit. Due to the decrease of available sand and possible cost reductions, Rijkswaterstaat is interested in the effects of new sand extraction strategies, i.e. larger extractions in terms of depth as well as extractions closer to the shore than current regulation allows.

For the morphodynamic impact we built a process-based idealized sand pit model in MatLab, which is used to model for tidal flow, sediment transport and bed evolution. The effects are presented in terms of area of morphodynamic influence, pit deepening, morphodynamic radius of influence and pit migration. For the impact on the significant wave height we use the Delft3D-WAVE model with storm conditions of different recurrence periods (100, 1,000, and 10,000 years). A sensitivity analysis for both models is carried out to analyse the effects of different pit geometries and pit locations on the model results.