Towards defining a baseline status of scarce groundwater resources in anticipation of hydraulic fracturing in the Eastern Cape Karoo, South Africa: salinity, aquifer yields and groundwater levels

Abstract

Abstract:The Eastern Cape Karoo region is water stressed and will become increasingly so with further climate change. Effective and reliable groundwater management is crucial for a development such as the proposed hydraulic fracturing for shale gas. This is especially critical across this region of agriculture and protected ecosystem services. The research, as part of baseline data gathering, aims to characterize the hydrochemistry for both the shallow groundwater (<500 m) and saline groundwater closer to the c. 2-5 km deep shale gas. The classification will be used to determine possible vertical hydraulic connectivity between the shallow and deep aquifers, prior to anticipated hydraulic fracturing. This paper reports on the baseline framework that includes the sampling design and a hydrocensus with field-recorded parameters shown as interpolated maps. This includes electrical conductivity, groundwater level and borehole yield. Together with completed sampling results, these data provide a record against which the environmental impact of hydraulic fracturing and the reinjection of production water can be determined. The research is a critical first step towards the successful governance of groundwater in light of proposed shale gas development in the Karoo. In its absence, effective regulation of the sector will not be effective.

Earth Stewardship Science—Transdisciplinary Contributions to Quantifying Natural and Cultural Heritage of Southernmost Africa

“…In these areas, possible sources are further determined using isotope analysis [54][55][56]. It was initially proposed that the relatively higher salinity south of the escarpments may be due to low precipitation and limited dilution of groundwater with fresh meteoric water [57]. However, new groundwater samples collected in this area have both 14C (Carbon) and 3H (Tritium) isotope signatures of deep (old) groundwater, usually saline and non-potable, mixed with shallow, modern groundwater, with ca.…”

Hydrogeochemical Analysis and Spatial Distribution of Groundwater Quality in Roundhill Landfill Vicinity of South Africa

“…10 The site is located between Nahoon and Buffalo river catchments and its geology is characterized by dykes and dolerite sheets dating to Jurassic age as well as Beaufort sediment of the Karoo family. 9 Area groundwater flows to the southeast and northeast and is classified as a minor aquifer with low groundwater yields of 1 L/s in most boreholes and a deep depth of >40 m. The area has clayey soils. 9 To evaluate the effect of leachate on groundwater, samples were collected in 3 monitoring boreholes near the landfill facility ( Figure 2).…”

“…9 Area groundwater flows to the southeast and northeast and is classified as a minor aquifer with low groundwater yields of 1 L/s in most boreholes and a deep depth of >40 m. The area has clayey soils. 9 To evaluate the effect of leachate on groundwater, samples were collected in 3 monitoring boreholes near the landfill facility ( Figure 2). A handheld GARMIN GPS-60 receiver was used to locate the sampling points whose coordinates were georeferenced and documented as shown in Table 1.…”

“…8 These challenges enhance leachate generation and its unmanaged flow, which increases its risk of contamination to surrounding resources. According to Stroebel et al, 9 groundwater is the most reliable and accepted source of water in the area. As such, incidents of leachate overflow and seepage from the faulty collection system in the landfill could lead to groundwater pollution.…”

Groundwater in fractured bedrock environments: managing catchment and subsurface resources – an introduction

“…However, at the same time, facing these challenges provides an opportunity for new proposed exploration projects to establish suitable monitoring programmes ahead of the start of exploration activities in order to minimize impacts on water resources. In this context, Stroebel et al (2018) present an approach to comprehensive groundwater baseline monitoring across the Eastern Karoo Basin in the context of proposed shale gas extraction in the region.…”