A team of eight leading South African hydrogeologists with more than 250 years of combined Karoo-specific groundwater experience led the study. The local specialists undertook a desktop review and held a workshop to identify and agree on key groundwater attributes and their significance across the Karoo region.
“The Karoo Groundwater Atlas represents a significant step in assisting us to better understand the Karoo’s groundwater and fulfilling our promise not to compete with the residents of the Karoo for their fresh water. It also highlights Shell’s commitment to an environmentally responsible approach to shale gas exploration,” said Jan Willem Eggink, Shell SA Upstream General Manager.
The Atlas identifies 10 key factors that assist to characterise the groundwater attributes of the Karoo, the most important being depth to water level, groundwater quality, presence of dolerite intrusions and groundwater yield.
The Atlas indicates that the yield, quality and natural refilling of the groundwater systems generally increase, or improve, when moving from west to east and from south to north in the Karoo. The Atlas includes consideration zones assigned to features such as dykes and boreholes to reflect the potential importance of their zones of influence.
The hydrogeologists concluded that shallow groundwater, at less than 300 metres in depth, is well understood and documented, however the deeper geological (hydrogeological) model requires further exploration. Further analysis, including geophysical data acquisition and exploration drilling, could contribute to a better understanding of this environment.
Shell has made all data gathered by the study freely available for research purposes. Stage Two of the Atlas is planned to further improve our understanding of the Karoo groundwater system by integrating physical additional water measurement and mapping around our proposed areas of operation. This work will be complemented by a further independent surface water study, commissioned to assess possible surface water sources for our operations, including waste water.
Eggink added, “Shell remains firmly committed to identifying, assessing and managing the associated groundwater issues related to our proposed Karoo shale gas exploration project.”
Benefits and next steps
The Karoo Groundwater Atlas provides South Africa with a comprehensive, versatile and interactive database and adds a meaningful new dimension to the literature available in the public domain, endorsed by a group of the country’s leading hydrogeologists.
The Atlas builds on Shell’s Environmental Management Plan – a public document submitted to the Petroleum Agency South Africa (PASA) as part of Shell’s exploration license application – and will assist the company in possible exploration activities in the Karoo.
The Karoo Groundwater Atlas is available for download from www.shell.co.za