Major issues in sustainable water supply in Botswana

Development of sustainable water supply in Botswana is hampered by the country's climatic. topographic and geologic conditions. The low rainfall and high potential evapotranspiration, combined with the country's flat topography and deep sandy soils, result in low rates of surface runoff and low rates of recharge to its groundwater. The estimated annual average run-off of 1.2 mm is one of the lowest in the world. All streams originating in Botswana are ephemeral. The low topographic relief of Botswana limits the construction of high dams storing large volumes of water. Groundwater development is hampered by low replenishment over most of the country and also by poor groundwater quality thigh salinity) in some parts. The water scarcity indicators and the water development constraints are a harsh reality, which leaves very little room for mistakes in water resources planning in Botswana. Optimum water development in a semi-arid country will be better obtained through a conjunctive use of surface and groundwater resources.