Rainwater harvesting as an alternative water resource in rural sites in central northern Namibia

Abstract In this paper, results of the investigations on rainwater harvesting (RWH) in central northern Namibia are described, which are part of the transdisciplinary research project CuveWaters. On the basis of hydrological and technical as well as social and cultural conditions, appropriate solutions for RWH are developed, discussed, and evaluated. The main objective is to analyse their technical and economical feasibility as well as their affordability for future users. In detail, two small-scale RWH systems are examined: roof catchments using corrugated iron roofs as rain collection areas and ground catchments using treated ground surfaces. The current status of local water supply and water use was investigated in the village of Epyeshona. Concepts and techniques of RWH were discussed with the population. Based on the results of these investigations and on the physical conditions, the appropriate RWH design and the required storage capacities could be identified. Local material and labour costs were determined and a dynamic cost analysis was carried out to compare the technological options in terms of amortisation times and prime costs. The feasibility of the RWH systems was assessed in relation to local socio-economic conditions. The calculations reveal that it is economically feasible to apply decentral techniques of RWH in terms of the roof catchment systems. Moreover, the proposed technologies provide comparable benefits to the public water supply. The ground catchment system, however, needs moderate subsidies to obtain the same benchmark.