Sediment pathways and morphodynamic response to a multi-purpose artificial reef – New insights

Multi-purpose Artificial Reefs (MPARs) are structures that may provide aesthetically acceptable coastal protection and improve recreational outcomes. Twenty years after construction of the first MPAR, Narrowneck Reef on Gold Coast Australia, most available literature is still focused planning, design such peer-reviewed publications their post-construction monitoring, interaction with sediment transport impacts morphology lacking. The aim this paper to evaluate how does influence transport, morphological changes around anthropogenic structure, two decades construction. To do so, a combination ten high spatial resolution topo-bathymetric surveys from top dune 10 m depth captured over 21 months series 60 simulations using calibrated numerical model were used. Our results demonstrate that: although not expected during or reported in similar structures, sand can bypass MPAR its offshore end; under oblique waves, longshore currents deflected as they pass reef, resulting shadow zone downdrift side where deposits; bar crest tends be higher reef's updrift compared downdrift, indicating act store for sediments, initially designed. Furthermore, stabilise it moves onshore offset inner result low wave incidence. presented here short-term response twenty more closely related build up deflection encounter reef than dissipation energy. This because MPARs designed dissipate just enough energy so achieve goal (surfing).