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Email the author (Login required) An interconnected system of tidal channels in Bahía Blanca estuary, Argentina: an evaluation of bedload sediment transport through acoustic methods
DOI: https://doi.org/10.3856/vol37-issue2-fulltext-10
Abstract
Bahía Blanca estuary located in the south of Buenos Aires province, Argentina, is characterised by a low coastal area with large tidal plains, islands, and a complex network of tidal channels of different dimensions. The latter form an interconnected tidal channel system. The aim of this study was to determine the net bedload sediment transport in an interconnected channel system (Cabeza de Buey, El Alambre, La Lista, and Principal channels) through an analysis of the morphological features of the bottom using acoustic data (echosounder and side scan sonar). Cabeza de Buey channel is connected to La Lista channel through El Alambre channel. The first two flow into the Principal channel. Cabeza de Buey channel has a flat bed of mud with very fine sand and medium-sized dunes of fine sand in its inner sector that display an asymmetrical section according to the ebb flow. These dunes continue to develop uninterrupted towards El Alambre channel, where large dunes (1.5 m high) of very fine sand originate. Their crestlines are either sinuous or barchanoid and they have their lee towards the ebb current. In La Lista channel, medium-sized asymmetrical dunes and large sand ribbons form on a rocky bottom according to the ebb flow. The sediment mobilized by the currents is characterized by the fine sand – silt fraction. The distribution and configuration of bed forms reveal that the bedload sediment transport is mainly concentrated in La Lista channel. Thus, only one tidal channel regulates the dispersal of sandy material, transporting a significant volume of sediment towards the shipping channel.
