Geographic Background to Zandvlei Estuary

The Zandvlei Estuary is the largest of eight estuaries on the False Bay coastline. It receives the bulk of its fresh water from three river systems draining the eastern slopes of the south Peninsula mountain chain. These are the Westlake, Keysers and Sand Rivers.

The Sand River starts as the Diep River, which rises above Constantia and flows through a series of greenbelts and public open spaces before crossing under the M3 Freeway and into Little Princessvlei and Zandvlei. After it leaves Little Princessvlei it becomes known as the Sand River.

The Westlake River has its source on the lower slopes of the Steenberg. It flows through the Steenberg Estate, Pollsmoor Prison and the Kirstenhof Wetlands before entering Zandvlei. Town’s False Bay coast.

The Keysers River rises on Constantiaberg as a series of small streams, most notable of these are the Grootbosch, Spaanschemat and Prinkasteel rivers. All of these rivers and streams, as with Zandvlei itself, have been affected by urban development and have been modified in various ways.

The vlei, under natural conditions, would dry out completely at certain times of the year. Zandvlei is, however a semi-estuarine system as a result of changes to its catchment and the mouth. The water level in the estuary is controlled by a rubble weir and a sand bar , which is opened periodically.

The Zandvlei Estuary drains into the northern point of False Bay with its mouth adjacent to the popular Muizenberg Beach. Zandvlei is the only functioning estuary on Cape Town’s False Bay coast.

The estuary was neglected in the past and was negatively affected by farming, urban development, dredging and the introduction of alien invasive species. The original vegetation has been partly restored through local government initiatives and the efforts of volunteers.

The Zandvlei Estuary is rated within the top 25% (as far its importance is concerned) of all the estuaries along the South African coastline.