Very little rainfall, on average less than 50 mm/a, occurs in the Namib Deserts. Its water resources are dependent on water brought down from subsurface or surface flow out of he inland where more favorable rainfall conditions prevail. The most important water resources are created by three of Namibia's western flowing rivers, which cross the central Namib into the Atlantic Ocean, i.e. the Omaruru, Swakop and Kuiseb Rivers. These form linear oases in the desert, not in the form of permanently flowing open water, but by the episodic recharge of the sandy aquifers underlying the river bed. Keywords: Namibia, Namib Desert, Kuiseb River, ephemeral rivers, flash flood, water resource, hydrology, rainfall variability.