Artificial reef site-specific design under upwelling favourable winds: Ría de Ares-Betanzos (NW Iberian Peninsula)

Abstract

The placement of artificial reefs on the seafloor alters the water velocity field, promoting proper nutrient circulation and thus improving the richness of ecosystems. This nutrient circulation is closely related to water currents, which in turn can be driven or influenced by wind action. The present work addresses the influence of the wind-driven circulation on the site-specific design of artificial reefs in the Ares-Betanzos estuary (NW Iberian Peninsula). To this end, a shallow water hydrodynamic circulation model is developed to compute the circulation induced by the wind, acting in conjunction with the other relevant forcings, namely the tide, river discharges, and its mixing with shelf waters. Particular attention is paid to average and intense wind-favourable upwelling conditions. The resulting velocity design parameters are used as input for near-field hydrodynamic analysis through computational fluid dynamics modelling around the artificial reef, and assess its proper design. It is found that the influence of wind action on the artificial reef design obtained for average conditions in absence of winds is limited. However, at certain locations, it is shown that wind action may induce sufficient hydrodynamic changes to require its consideration.