14. Drought as a Catalyst for Change: A Case Study of the Steenkoppies Dolomitic Aquifer

Karst aquifers in dolomites are the single most important type of aquifer in South Africa. One such aquifer is the Steenkoppies Aquifer, situated west of Tarlton (26°02′–26°13′ S, 27°29′–27°39′ E), which covers an area of 213 km² with a catchment area of 311 km². A perennial spring, Maloney’s Eye that discharges into the Magalies River, serves as the only natural outlet for the groundwater stored in the aquifer. Discharge from this spring, for the last 100 years, varied between 0.05 and 1.035 m³ s⁻¹ with an average of 0.455 m³ s⁻¹. The standardised precipitation index (SPI) was used to evaluate the potential affect of meteorological and hydrological drought on this aquifer. The region has experienced two distinct periods of severe and extreme meteorological drought during the last 27 years (1990–1992 and 2002–2005). The cumulative rainfall departure (CRD) method was used to evaluate the relationship between precipitation and spring discharge. There is a reasonable correlation between the CRD, with a short-term moving average of 9 months and a long-term moving average of 60 months, and the discharge from Maloney’s Eye. However, since 1987, the actual discharge from Maloneye’s Eye is lower than the simulated discharge, indicating that external factors such as abstraction may play a role and enhance hydrological droughts. These droughts have provided the primary stimulus for a change in the behavior and attitude of the groundwater users relying on the Steenkoppies Aquifer, which resulted in processes being initiated to measure, monitor, and manage water abstraction from the Steenkoppies Aquifer.