Estimating the groundwater reserves in the river and dunes areas along the lower Kuiseb River in Namibia: Exploration for groundwater in the Namib Desert from 1992 to 1995 provided information about the hydrogeology of the dunes area south of the lower Kuiseb River. The model calculations based on this information indicate that the groundwater stored in the fossil river beds of the Kuiseb cannot be viewed as a possible source of water. The rather infrequent flash floods of the present Kuiseb contribute little to the groundwater recharge of the dunes area. Model calculations show that the occasional groundwater recharge along the present Kuiseb River between Swartbank and Rooibank allows only limited withdrawal. Keywords: Hydrogeologie, Grundwasserexploration, Modellrechnungen, fossile Flußtäler, Kuiseb-Fluß, Namibia, Afrika.