Using Remote Sensing Data to Model Groundwater Recharge Potential in Kanye Region, Botswana

Abstract

This study focuses on the groundwater recharge potential in the upper Limpopo catchment starting from Kanye region in South Botswana. Existing high resolution remote sensing data were used to estimate the spatial distribution of potential recharge anddischarge of aquifers in this semi-arid region. 29 NOAA AVHRR images available for Southern and Central Botswana between 1996 and 2000 were analyzed to produce 29 Kc maps. The comparison of Kc maps in wet and dry seasons shows similar patterns over the upper Limpopo catchment in Kanye region. The conclusion can be drawn that the Kc pattern does not significantly change with time over the region. Therefore the time averaged Kc map can be used together with a map of potential evapotranspiration to calculate actual evapotranspiration for the period 1996-2005. Ten year averages of actual evapotranspiration and precipitation together with the averaged discharge of the catchment to the Limpopo River are then used to calculate a potential recharge/discharge map using the water balance equation. The problem of passing from the potential recharge/discharge map to the actual recharge/discharge map will have to be solved in future research.