Determination of recharge patterns by combining remote sensing and the chloride method

Water supply in semiarid Botswana is, to a large extent, based on groundwater. In the planning of a groundwater abstraction scheme, criteria for the sustainability of the abstraction with respect to both quantity and quality have to be satisfied; groundwater models can aid this task. The most important model parameter in the context of quantitative sustainability is the long-term average groundwater recharge together with its spatial distribution. A method is developed to calculate a recharge map that can be used in a groundwater model. The distribution of recharge is obtained from remotely sensed data and the absolute values of recharge are derived from the chloride method.