its main tributary is the doring river, changing name as melkboom/oudrif before it joins the olifants. the tributaries flowing from the east, such as the thee river, noordhoek river, boontjies river, rondegat river and the jan dissels river are typically perennial, except for the sout river. those flowing from the west, such as the ratels river, elandskloof river and the seekoeivlei river are smaller and seasonal, not contributing much to the flow in the system.