Geomorfología y dinámica del Canal San Blas, provincia de Buenos Aires (Argentina)

the bahía anegada is the coastal zone of the southern part of buenos aires province (argentina), where several environments are recognized: islands, inlets, marshes, tidal plains and different types of beaches. the bahía san blas is located at the southern part of the bahía anegada, where the san blas channel separates the mainland from an island (fig. 1). the san blas channel is 2.5 km wide and 12 km long. the study area has a tidal amplitude characterized by a mean of 1.62 m, being 2.20 and 0.58 m the high and low tide respectively. the present study shows the results of a bathymetric survey of the san blas channel and an analysis of the behavior of the tidal currents that affect sediment transport and promote the generation of different bedforms. the aim of this study was to analyze the submarine geomorphology related to the dynamic conditions in order to characterize in detail the sedimentary conditions in this area. a detailed bathymetric study was conducted over a zone of 50 km2, covering the san blas channel, through a digital echosounder bathy-500 positioned by dgps operating in real time. fifteen transversal tracks and three longitudinal tracks were made at the san blas channel in order to obtain the necessary bathymetric profiles to make a bathymetric chart of the area. over a zone of 1.5 km2, characterized by a field of subaqueous dunes, a phase measuring bathymetric system (fmbs), called swath bathymetry system "geoswath plus" from geoacoustics lt. (uk), was employed in order to determine the detailed dune morphology. this survey yielded details and disposition of the bedforms present on the channel bed with centimetric precision. bottom sediment samples were collected and tidal currents were measured using an acoustic doppler current profiler (adcp) mounted on a ship. the tidal currents were measured during a whole tidal cycle, obtaining the distribution of velocity and direction over the water column, on a track carried out transversally to the channel