Episodic recharge of groundwater due to cyclonic events within the Limpopo province, South Africa

Abstract

Research was conducted based on long-term groundwater monitoring data to investigate the effect of cyclones on episodic recharge in the Limpopo province. Episodic recharge was mathematically defined through empirical observations, as modelling episodic recharge requires a very detailed dataset and the spatial scale of the study area rendered this modelling approach impractical. A detection algorithm based on the aforementioned episodic recharge definitions was developed and applied to boreholes with long-term historical water levels and the cyclone database along the eastern seaboard over the same periods. The correlation between cyclones making landfall, tropical storms and tropical depressions moving within 100km from Mozambique's and South African coastline were calculated with respect to the defined episodic recharge definitions. The maximum rainfall associated with the aforementioned events were also studied. Although some cyclone events do coincide with the episodic recharge events, the study showed that cyclones is not the driving factor for episodic recharge in the Limpopo province despite some evidence from long-term monitoring data that might suggest this