Patterns and Rates of Sedimentary Infill in the Minnamurra River Estuary, South-Eastern Australia

Panayotou, K., Woodroffe, C.D., Jones, B.G., Chenhall, B., Mclean, E. and Heijnis, H., 2007. Patterns and rates of sedimentary infill in the Minnamurra River estuary, south-eastern Australia. Journal of Coastal Research, SI 50 (Proceedings of the 9th International Coastal Symposium), 688 – 692. Gold Coast, Australia, ISSN 0749.0208 This paper presents a revised process-based model that explores aspects of estuarine geomorphology and the rates and patterns of sedimentary infill based upon the Minnamurra River estuary, a mature barrier estuary in south-eastern Australia. The Minnamurra River is located on the south coast of New South Wales and is characterised by three main facies: a marine flood tide delta/barrier, a central lagoon/estuary and a fluvial delta. The sedimentary record in this system was examined in detail to quantify the rate of estuarine infill. This predominantly infilled mature barrier estuary is now largely dominated by river influence. In the early stages of evolution this wave-dominated estuary was characterised by a central mud basin which trapped sediment supplied from the catchment. In the latter stages of evolution, decreased accommodation space restricted sediment retention within the basin, enabling the river to potentially contribute sediment directly to the coast. . The record of sediment retention for this wave-dominated estuary demonstrates that the rate and pattern of infill has changed with time as this system has become increasingly dominated by river influence.