MORPHODYNAMIC EVOLUTION AND INFLUENCE OF DREDGING ACTIVITIES IN SMALL-SCALE MESOTIDAL ESTUARIES: THE CASE OF PUNTA UMBRIA (SOUTHWESTERN SPAIN)

摘要

As in many others coastal systems, the interplay between tide and littoral drift controls the inlet morphodynamics of the Punta Umbria estuary (SW Spain). Their interaction causes that the estuary mouth has a natural tendency to closure, altering the economic activities related to the navigation through the inlet. The situation is no longer sustainable, since the regional government needs to dredge the navigation channel every two years. In order to understand the hydrodynamics and its impact on the morphology, a monitoring network was installed between May and October 2014, all along the estuary and the inner continental shelf. The measurements, combined with detailed bathymetric information between 2002 and 2014, enable the set up, calibration and validation of the computational model Delft3D. Three possible management scenarios are then analyzed. The long-term stability of the inlet is assessed through tidal prism and littoral drift relations. Attending these simple but robust relations, the best alternative to extend the useful life of dredging is the construction of a sediment tramp nearby the estuary mouth.