This work describes the dynamics and evolution trend in two similar beaches located in NE Sardinia (La Cinta beach and Budoni beach), composed of fine to gravelly quark sand, backed by well- developed dune ridges and lagoons. The study began a few days after the flood on the 24'" of September 09, which caused the breach of dry-beach and openings on both beaches. Medium-term evolution, over a period of 55 years, was canied out using ortho-images (years 1954, 1977, 1997, 2000, 2003,2006,2008, SPOT 5-2009) used for reconstruction of coastline changes at this temporal scales. Short-term variations have been periodically monitored using topo-bathymetric digital models, derived from data acquired in 6 different field surveys (DGPS data and Echo-sounder data). Coastline evolution was reconstructed by means of measurements made at 5 transects per beach homogeneously spaced. Sedimentary and hydrodynamic characteristics were studied. Models of wave motion and hydrodynamics were created using Defft3D software. The results obtained from these models (wave ray direction, deep current distribution, structure and surf-zone dynamics) allowed to visualize the response of both beaches to windlwaves stress, forced from NE, E, SE prevalently (wind intensity 18mls, 1 Omls). The comparison between data collected, thematic maps and models allowed to identify the main controls and distribution mechanisms of the sedimentary paths on the shoreface. Results demonstrate, in medium-term scale, the stability of both beaches and, in short-term scale, the height resilience of this beaches, with tendency to reestablishment of steady state with short relaxation times.
Medium and short-term evolution of two beaches on NE Sardina: La Cinta (San Teodoro, OT) and Budoni (OT)
BATZELLA, TIZIANA;KALB, CLAUDIO;IBBA, ANGELO;DEMURO, SANDRO
2012-01-01
Abstract
This work describes the dynamics and evolution trend in two similar beaches located in NE Sardinia (La Cinta beach and Budoni beach), composed of fine to gravelly quark sand, backed by well- developed dune ridges and lagoons. The study began a few days after the flood on the 24'" of September 09, which caused the breach of dry-beach and openings on both beaches. Medium-term evolution, over a period of 55 years, was canied out using ortho-images (years 1954, 1977, 1997, 2000, 2003,2006,2008, SPOT 5-2009) used for reconstruction of coastline changes at this temporal scales. Short-term variations have been periodically monitored using topo-bathymetric digital models, derived from data acquired in 6 different field surveys (DGPS data and Echo-sounder data). Coastline evolution was reconstructed by means of measurements made at 5 transects per beach homogeneously spaced. Sedimentary and hydrodynamic characteristics were studied. Models of wave motion and hydrodynamics were created using Defft3D software. The results obtained from these models (wave ray direction, deep current distribution, structure and surf-zone dynamics) allowed to visualize the response of both beaches to windlwaves stress, forced from NE, E, SE prevalently (wind intensity 18mls, 1 Omls). The comparison between data collected, thematic maps and models allowed to identify the main controls and distribution mechanisms of the sedimentary paths on the shoreface. Results demonstrate, in medium-term scale, the stability of both beaches and, in short-term scale, the height resilience of this beaches, with tendency to reestablishment of steady state with short relaxation times.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
