OUR COASTAL TREASURE
The Sand River and the Dunefields
The Sand River only flows through a short section of the Oyster Bay Dunefield, a headland bypass dunefield that stretches from Oyster Bay to St Francis Bay. The Sand River rises in the farmland north of the dunefield and joins the dunefield about 3 km upstream from the Sand River Bridge.
There is often no visible water flow and even when there is a flow, it is generally more a stream than a river. On at least ten memorable occasions however, there has been flash flooding after a period of high rainfall.
Recent floods in 2011 took out first the bridge and then its temporary replacement. Before that, a 1996 flood from the Sand River came right through the canal area, creating some short-lived but impressive waterfalls into the canals. Following that event, the Sand River was diverted into the Kromme and the canals were not affected by the later floods.
Although the river creates occasional excitement, it is not nearly as interesting as the dunefield it flows through.
Thanks to wind and water, the dunefield is constantly moving and looks different every time you walk along it. There are pools of water in the slacks between the dunes and although some are more permanent than others, you can’t count on finding a pool where you last saw it – especially if there has been no rain.
The Oyster Bay dunefield is one of three headland bypass dunefields in the St Francis area, two large and one very small. The large ones are the Oyster Bay Dunefield and the Thysbaai Dunefield, and the small one cuts across Shark Point.
The two larger dunefields are the only remaining large dunefields of this type that are still active in South Africa. The Oyster Bay dunefield, at 16km long, is the longest existing headland bypass dunefield in South Africa and one of the largest in the world. The St Francis dunefields are considered to be unique at all levels, on a local, regional and probably global scale.
The dunefields are dynamic, sensitive systems that are constantly changing in response to natural and human activity. Click here to see the changes over the years.
What happens when human activities affect the dunefields is often more than we bargained for. Read more about this in the Impacts on the Dunefields section.