History of the Cape Flats Vleis (Part II): Rietvlei

24 April 2011

This is the second contribution to this short series and in itself is a short contribution dealing with Rietvlei (see here and here for earlier renditions).

North-east Rietvlei

A good summary of the history of Rietvlei is contained in the ECRU Report on this vlei system (downloadable here).  I want to address a couple of aspects of the lesser-known history.

Rietvlei comprises three components, the vlei proper (the saltmarsh), the area of standing water which is man-made and was created when sand was needed for the harbour breakwater and the dune-beach system bordering it on the west and previously to the north.  The salt marsh system is ecologically-important, has wet, marginal and dry vegetation types, soil-salinity transects that dictate vegetation zones and bears strong type-similarities to other salt marshes on other continents (see Harding et al).  Regrettably, the dual pressures of urbanization, altered hydrology and poor management are leading to the progressive loss of this very sensitive matrix of seasonal and ephemeral environments.

Channelling the Diep River past the vlei

The Diep River, now passing alongside the vlei via Brooke’s Folly (apologies to Dave Brooke) to collect the effluent from Potsdam sewage works and place it carefully in the estuary, used to discharge to the north of the present vlei system – in fact evidence of two former outlets has been found.  Most interestingly, the yellowwoods of the Knysna Forest system used to extend all the way to Milnerton (the climate was wetter then).  This information is contained in a most interesting work by HJWG Schalke, entitled The Upper Quarternary of the Cape Flats Area (published in Scripta Geologica, Volume 15, 1973), in which he sampled pollen records all the way around our coastline.

Estuary outlet to the Atlantic

One Response to History of the Cape Flats Vleis (Part II): Rietvlei

  1. Adnan Bashir says:

    ‘Would LOVE to Initiate A Project to Reintroduce Yellow Woods onto the Cape Flats & Surrounds – ie. get each household to grow a tree from scratch holding its own intent for a fruitful future !

Leave a Reply

Your email address will not be published. Required fields are marked *