This paper summarises the lessons learned during the planning and construction of four rainwater harvesting (RWH) pilot plants in the village of Epyeshona (400 inhabitants) in central northern Namibia. The main problem of the region is that the water demand of its population exceeds the local natural resources. The rainfall in the project region is extremely variable (50–990 mm per year), evaporation rates are high, perennial rivers do not exist, and groundwater aquifers are saline due to low soil permeability and high evaporation. The project's activities were prepared and accompanied by stakeholder participation and capacity development. The village community chose the techniques and pilot sites in several participatory workshops. Three roof catchment systems with differing tank designs (polyethylene, ferrocement, and concrete bricks) for individual households and a concrete-lined ground catchment facility for six households were built. The collected water is supposed to be used for horticulture. Hence, gardening plots and drip irrigation systems were created. Selected trainees were trained to build, operate and maintain the RWH systems and gardens. Finally, the pilot plants were monitored and evaluated to examine their social and technological feasibility.

Rainwater harvesting to irrigate small-scale gardens enhances food self-sufficiency to overcome rural poverty. So far rainwater harvesting is not encouraged by the Namibian National Water Supply and Sanitation Policy nor supported financially by the Namibian government. This study proposes two rainwater harvesting facilities to irrigate gardens; one collects rain from household roofs with tank storage, the second collects rain on a pond roof with pond storage. The aim of this paper is to assess the benefits of rainwater harvesting-based gardening and to propose policy and financing implications for the Namibian government. We investigate the benefits of rainwater harvesting through a literature review, a cost-benefit analysis, monitoring of project pilot plants and a comparison with the existing irrigation and drinking water infrastructure. The results indicate that rainwater harvesting offers numerous benefits in technological, economic, environmental and social terms. The facilities have a positive net present value under favourable circumstances. However, material investment costs pose a financing problem. We recommend that government fund the rainwater harvesting infrastructure and finance privately garden and operation and maintenance costs. Integrating these aspects into a national rainwater harvesting policy would create the conditions to achieve the benefits of an up-scale of rainwater harvesting based gardening in Namibia.

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