From scour to dune migration: understanding and predicting seabed mobility near offshore structures at different spatial scales

Several offshore wind farms (OWF) are currently operating or being developed on a series of sand ridges on the Belgian continental shelf known as the Flemish Banks. In order to guarantee the stability of structures such as subsea cables and turbine foundations, the minimum and maximum projected bed level over the project lifespan should be known. Two applications are discussed in which sea bed dynamics are constrained to optimise the design of OWFs. The Jacket Scour Predictor (JaSP) model, a data –driven model of time-dependent scour depth development for jacket foundation, is presented. The model calibration allows to identify potential shortcomings of existing formulations. The estimated sea bed level (ESBL) methodology allows to define defendable bounding values of expected sea bed mobility in the absence of structures, based on a statistical analysis of dune migration rates.