Coastal and nearshore morphology, bedforms and sediment transport pathways at Teignmouth (UK)

The beach and nearshore area of Teignmouth (UK) has been the object of a multidisciplinary research project, COAST3D, carried out by 11 European institutions. This paper emphasises the sedimentological and morphological investigations of the intertidal and nearshore area using a variety of techniques. From the results presented, it is clear that the Teignmouth site is very dynamic. Sediment mobility is high during fair-weather conditions owing to the strong jet-like current flows associated with the presence of the narrow estuary mouth. The beach at Teignmouth can be categorised as composite with a dissipative low-tide terrace and a reflective upper beach. From surficial sediment sampling, selective transport processes were identified, imposed by the high current velocities at the estuary mouth. This process also leads to the formation of characteristic depositional lobes with poorly sorted sediment. From digital side-scan sonar mosaicing, cross-shore and longshore-oriented bedforms could be observed, with their characteristics being dependent on the pre-survey hydro-meteo conditions. Although the nearshore system is dominated by the jet-outflow, littoral drift processes can also be important. They proved to be im portant for beach morphological changes leading to a rythmic alongshore beach behaviour which was attributed to a reversal of the littoral drift imposed by a period o