Barchan vs Monopile: what happens when a barchan dune finds an obstacle in its path?

The impact of barchan dunes colliding with one another has been well observed, understood and modelled. But what happens when there is an immobile obstacle, an Offshore Wind Farm (OWF) monopile foundation, in one’s path? At the case study OWF a monopile was installed ~45 m downstream of the slip-face of an approaching barchan dune. Six bathymetric surveys, over a 20 year period, are analysed capturing the impact of the monopile on the dune’s evolution. The dune migrated relatively consistently, at a rate of 20 to 25 m/year. The re-appearance of the jack-up rig spudcan footprints in the wake of the barchan indicates that the dune does not exchange material with the seafloor and that the sedimentary composition of the two must be distinct.