Plettenberg Bay, South Africa 21 June – 30 June 2024

Shifting Sands


A history of change of the Keurbooms estuary

The Keurbooms Estuary is formed by the confluence of the Keurbooms and Bitou Rivers, flowing into a lagoon situated behind a sandy barrier dune bounded in the south by the Lookout Rocks and in the north by a hard core of carbonate cemented beach/dune sand. This narrow back-barrier lagoon extends over a distance of almost 4km, but is only about 500 m wide. Such coastal lagoons and associated barrier beaches often form prime tourist attractions, and this is certainly the case with Lookout Beach and the Keurbooms Estuary. The effect of human influences on the functioning of the estuary/lagoon system can be considerable, and extreme events can also cause extensive damage to infrastructure built around the lagoon. There is no evidence that the mouth has ever closed.  This talk will present the results of an extensive study from 2005 to 2018 of 35 GPS surveys conducted at low and high tides, including spring tides, detailing the substantial changes that have taken place and relating them to the sediment structures and the dynamics of the system. In particular, damage to infrastructure has occurred and will occur in future and a knowledge of the system will enable better management. This also applies to possibilities of coordinating the position of the estuary mouth, and the consequences of climate change.


Dr Eckart Schumann is a physical oceanographer, i.e. his interests lie in the physical aspects of the ocean and coastal environments. This involves the processes and dynamics of these areas, including weather and climate. He has a BSc and BSc (Hons) from the University of KwaZulu-Natal (UKZN), MSc from the University of South Africa, MSc from Cambridge University and a PhD from UKZN. He has published more than 70 papers in international refereed journals and books, edited a book, presented more than 50 papers at international conferences, and written more than 100 reports and contract reports on various aspects of coastal and estuarine dynamics, weather and climate, as well as a number of popular articles. He has been involved with a number of South African research programmes as member and leader, as well as representing South Africa on international bodies such as IUGG, IAPSO, SCOR and CORPWIO. In 1982 he was a guest investigator at WHOI. He was Head of the Physical Oceanography Division of the National Research Institute for Oceano¬logy NRIO, CSIR, and Alternate to the Director, Marine Sciences before joining the new Department of Oceanography at Nelson Mandela University (NMU). As such he has undertaken numerous scientific cruises and is a scientific diving instructor with more than 300 dives. He retired from NMU in 2000 and has continued as a Research Associate while doing consulting work.

This event takes place on:

Saturday 22 June

15:00 - 15:25