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Abstract

With a mean annual rainfall of about 285 mm Namibia is one of the driest countries in Africa. The high demand for water due to a growing population and economy and an expected increase hydroclimatic extremes resulting from climate change, requires the country to effectively manage limited water resources. Since only 1 % of rainfall recharges the groundwater and only 2 % generates ephemeral runoff, the country consequently relies extensively on harvesting surface and groundwater and storing this water in dams for agricultural production, domestic and industrial water supply. The total storage capacity of the major water supply dams in Namibia amounts to about 710 million m³, with a total water consumption of about 300 million m³ for the municipal sector (~24%), industry (~5%), livestock (~26%) and irrigation (~45%) in 2000. The balance of Namibia’s water supply and demand was tested to its limits in the recent prolonged drought experienced by most of southern Africa. By the end of 2019, due to the worst drought in Namibia in 90 years, the full capacity of the capital’s main supply dams was at less than 20%. We will present an analysis of 40 years of satellite-based precipitation data and dam inflows showing an alarming trend and vulnerability of the country’s water supply to rainfall variability and projected climate change, which requires a paradigm change in managing Namibia’s major source of water supply, particularly in the perspective of a likely increase of droughts in a future climate.