A FIRST INVESTIGATION INTO THE IMPACT OF VERY LARGE-SCALE OFFSHORE SAND MINING ALONG THE DUTCH COAST

Jebbe van der Werf, Alessio Giardino, Jan Mulder, Ad Stolk

Abstract


This paper investigates the impact of very large-scale offshore sand mining along the Dutch coast on waves, currents, sand transport rates and morphology. To this end, we simulate different extreme sand extraction trench geometries (depths between 1 and 17 m, volumes between 10 and 63 x 109 m3) with the process-based modelling system Delft3D. The simulations show that the waves become 0-20% higher, currents change with 0-0.3 m/s and transport rates with 10-80%. In general, the trench has a negative effect on the sand balance of coastal sections, especially near the narrow part of the deepening. The estimated trench impact on dune erosion during normative storm conditions with a frequency of occurrence of 1/10,000 yr is 5-10%. The impact of the deepening is generally seen to increase with depth.

Keywords


dune erosion; marine sand extraction; morphological modelling; Netherlands Continental Shelf; sea level rise

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