These rivers, in the wet season and in places, have plenty of water, generally dissipated in vleis, pans and vloers (marshy and lake land).
Shallow sheets of water termed vleis, usually brackish, accumulate after heavy rain at many places in the plateaus; in the dry seasons these spots, where the soil is not excessively saline, are covered with rich grass and afford favourite grazing land for cattle.
Besides these pans there are in the interior plateaus many shallow pools or vleis whose extent varies according to the dryness or moisture of the climate.
West of Knysna, and separated from the seashore by a sandbank only, are a series of five vleis, turned in flood times into one sheet of water and sending occasional spills to the ocean.
These vleis are known collectively as " the lakes."
In some of the vleis and streams in which the water is intermittent the fish preserve life by burrowing into the ooze.