African Wildlife and Environment Issue 66

DESTINATION

DESTINATION

December 2007

Floods, the Keurbooms Estuary & LOOKOUT BEACH

There is a certain amount of subjectivity involved in the process, particularly on the beach face with ocean waves present. Moreover, the accuracy of the GPS is not better than a few metres, but the changes in sediment structures were so massive that such small deviations do not affect the conclusions in any substantial manner. Photographs, as well as Google images, were used to augment the structures depicted in the text. I was fortunate to cover the effects of three major floods over the next nine years, which caused dramatic changes in the morphology of the estuary. These changes also had a substantial effect on infrastructure and tourism insofar as Lookout Beach is concerned.

Plettenberg Bay, on the south coast of South Africa, is the chosen destination of large numbers of tourists each year. It has a wide range of attractions, including beautiful beaches, top-class hotels, boating, sailing, surfing, diving, fishing, hiking and nature reserves. To locals and those in the know, it is simply called ‘Plett’. Prime amongst Plett’s attractions is the Keurbooms Estuary, with its associated Lookout Beach. The estuary is formed by the confluence of two rivers, namely the Keurbooms River itself, and its tributary the Bitou River. The two estuaries combine to form a narrow back-barrier lagoon behind a sandy barrier dune which extends almost four km. The geology of the area is shown in Figure 1, and of specific interest are the Lookout Rocks in the south, and a hard structure of carbonate-cemented dune

As an occasional visitor to Plettenberg Bay, I decided in 2005 to start using a GPS to survey the Keurbooms Estuary. This involved running/walking along the water’s edge on the beach and in the estuary while marking out the route on the GPS; waypoints were taken at suitable locations. Where possible this was done at low and high tides, and more specifically at spring low and high tides. These two surveys could then give an indication of the intertidal sediment distribution. 2005 - 2014

Dr Eckart Schumann

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33 | African Wildlife & Environment | 66 (2017)