Longshore sediment transport and changes in submarine morphology: Brighton Beach, Adelaide, SA
Principal Investigator: Miot da Silva
This proposal presents a study of surf zone longshore sediment transport, nearshore dynamics and changes in submarine topography in a low wave energy environment. The study area is Brighton Beach, located in Gulf Saint Vincent and therefore protected against the high and persistent swells from the Southern Ocean. These energetic waves on the open coast approach Brighton with much reduced energy and frequently at a high angle, producing significant longshore sediment transport rates which are responsible for the formation and evolution of highly dynamic submarine sand bars and hence changes in submarine and beach morphology. Understanding the patterns and rates of sediment transport along low energy systems and how these factors control the general coastal barrier evolution is important since these analyses can provide critical information on, for example, how new pulses of sediment under high-angle waves can potentially generate and modify submarine bars and consequently create new erosion hot spots down the coast. These data and scenarios can be applied to management activities where beaches are currently being nourished with sand to minimize or ameliorate coastline erosion. This project will provide valuable information about rates of longshore sediment transport under periods of fair weather and storms, in efforts to understand mechanisms of environmental adjustment, long term metropolitan beach erosion, and impacts under threats such as climate change (e.g. changes in wave energy) and sea level rise.
A kayak-echosounder system has been built for this project and initial data has been gathered along the Adelaide Metropolitan Coast.