Forecasting lagoon outlet erosion: KwaZulu-Natal, southeast Africa

ABSTRACT Smith, A.M., Guastella, L.A., Goble, B.J., 2014. Forecasting lagoon outlet erosion: KwaZulu-Natal, southeast Africa. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 151–156, ISSN 0749-0208. The Amanzimtoti Lagoon is at the mouth of the Amanzimtoti River. The lagoon outlet changes systematically in response to the 18 year long Dyer-Tyson summer rainfall cycle (DTC). During the dry part of the DTC the lagoon is generally closed, opening only during heavy rainstorms. When closed the lagoon is separated from the sea by a baymouth bar, varying from 30 to 60 m wide. The open-days per year have increased dramatically as the DTC has entered the wet phase. Early in the DTC the lagoon rarely opened, and when this occurred it breached near the centre of the headland bound bay, but as the DTC-driven runoff cycle has progressed the outlet has remained open. However, during this open phase...