Investigating Risks To Groundwater Systems In The Main Karoo Basin Of South Africa

The improvement in hydraulic fracturing techniques resulted in the exploitation of natural gas associated with low-permeability organic-rich shale formations in the United States. South Africa has prospective shale gas resources linked with the marine black shales of the Whitehill Formation found in the Karoo Basin. Plans exist to develop the Karoo shale gas resources to diversify the primary energy mix. However, concerns among stakeholders about groundwater contamination and source of water for hydraulic fracturing remain unresolved. Such concerns include the potential of spills, fugitive gases, mechanical well integrity, and water management practices individually and collectively to introduce methane, hydrocarbons, metals, radionuclides, or other chemicals in groundwater posing human and environmental health-related risks. However, such concerns have not been assessed to provide evidence-based results that can be used to develop either an early warning or mitigation or adaptive monitoring system for shale gas development activities. The study was designed to develop a conceptual risk assessment model of potential shale gas operations to provide insights for groundwater protection. The western part of Greater Karoo Basin was used as a case study area. Applying this model suggests that hydraulic fracturing itself will have low risks in contaminating groundwater resources. However, the risks for over-abstracting groundwater remain high. These results suggest that it is crucial to learn from countries which have practised hydraulic activities for long periods of time, especially countries where the environmental setting are similar to South Africa. These findings form the basis of designing field-based studies that will influence policy making for action planning.