Small Scale Rain- and Floodwater Harvesting for Horticulture in Central-Northern Namibia for Livelihood Improvement and as an Adaptation Strategy to Climate Change

Abstract

This paper presents research results of the German-Namibian joint research project CuveWaters in which different technologies for small-scale rain- and floodwater harvesting were introduced as pilot plants in central-northern Namibia as part of a broader Integrated Water Resources Management (IWRM) approach. Central-northern Namibia has semi-arid climate conditions with clearly distinctive dry and wet seasons. Rain- and floodwater harvesting for irrigation purposes are intended to increase resilience in agricultural production by building buffers for interseasonal dry spells and to make irrigation farming possible during the dry season. This is intended to improve availability of vegetables in rural parts of Namibia and to derive income on local markets. Besides raising temperatures, climate change in sub-Saharan Africa is predicted to increase rainfall variability. Therefore, these adaptations also present a precondition for adapting to future climate change. Within the project, different organisational approaches such as harvesting of rainwater at the household as well as at the communal level were tested, as well as different locally available tank construction materials. All technologies were developed in cooperation with the local communities and framed by capacity development measures which yielded very good results and enabled a diffusion of the technology in the region. Based on 5 years of research the construction of ferrocement tanks on the household level and ponds covered with shade nets on the communal level can be recommended. Due to high evaporation rates all gardens irrigated with harvested rainwater were equipped with water saving drip irrigation systems. In combination with capacity development focusing on water management this enabled the users to irrigate their gardens throughout the dry season.