Aquifer Water Level Behaviour In Relation To Deluge And Drought At Eskom's Thyspunt Site, Oyster Bay, Eastern Cape

The paper presents the groundwater monitoring data collected at Eskom's Thyspunt Site over the eleven-year period from January 2008 to January 2019. The Thyspunt site is underlain by an upper unconfined intergranular aquifer of the Algoa Group sediments, called the Algoa Aquifer, and a deeper semi-confined fractured-rock aquifer of the Table Mountain Group, called the TMG Aquifer. In the Algoa Aquifer, the highest water levels were recorded after the very good winter rains of 2011 and 2012. Between 2013 and January 2019 the recorded water levels in this aquifer have been declining to the lowest measured levels since monitoring started in 2008. This decline varies from 11.0 m in the Oyster Bay dune field recharge zone to 0.8 m in the Langfonteinvlei discharge zone. The deeper TMG Aquifer shows a similar decline over the last four years ranging from 10.1 m in the inland recharge zone where the TMG outcrops to 1.3 m at the near coastal discharge zone.