In order to obtain a better understanding of a groundwater system, it is very important to understand the recharge mechanisms of such a system. Several intensive investigations have been done, documenting the different methodologies to derive recharge. Most of these studies have been centred on the detailed analysis and description of isotopes, which are either a characteristic of the water, the rock, or both. The isotopes of strontium, in particular the isotopic 87Sr/86Sr ratio, is one of such methodologies applied to drive the sources of recharge.

To control the impact of nitrate and its sustainable mitigation in groundwater systems used for drinking water production, it is crucial to understand and quantify sources as well as biochemical processes which (permanently) remove nitrate.

In an alluvial aquifer in Germany (Hessian Ried) that serves as major drinking water recourse for the Frankfurt metropolitan area, water quality is challenged by nitrate contamination from intensive agricultural land use locally by far exceeding the drinking water limits of 50 mg/L.

The past few years hydraulic fracturing has been a hotly researched topic. Currently, most published documents are just speculation of what can happen if hydraulic fracturing is to take place in South Africa. There is very little work done to firstly establish a baseline on the current groundwater quality and secondly look at the current state of the groundwater around the Soekor wells. For these reasons a geochemical investigation was launched looking at the Soekor wells and the surrounding boreholes to determine a valid baseline.

Anticipated Shale Gas Development could intensify possible natural hydraulic connectivity between deep groundwater reservoirs and shallow aquifers in the Karoo. This project attempts to test geochemical evidence of natural mixing between old groundwater from deep aquifers and young groundwater from shallow aquifers using selected isotopic signatures in conjunction with borehole yields. Borehole yields were determined using slug tests. All isotopes (δ18O, δ2H, δ13C, 3H and 14C) were analysed in the laboratory of Environmental Isotope Group of iThemba Laboratories in Gauteng.

The Table Mountain Group is a major fractured rock aquifer system throughout the Western Cape, with many interconnected but semi-independent parts, each having its own recharge area, flow paths and discharge area. Groundwater is known to travel long distances and reach great depths, including through the Olifants River syncline, such as at The Baths hot spring near Citrusdal. Stable isotope compositions of rain and groundwater in the Cederberg and Olifants River Mountains were measured over a period of 2-3 years.

Limpopo Province is one of the wealthiest areas of South Africa with respect to geothermal spring occurrences, which were classified according to the residing mountains: Soutpansberg, Waterberg and Drakensberg. Mphephu, Sagole, Siloam and Tshipise geothermal springs fall within the Soutpansberg. This study is aimed at understanding the origin and age, geochemical processes controlling the water chemistry. Analyses of major ion hydrochemistry and environmental isotopes (?18O, ?2H and ?3H) were undertaken, which is supported by conventional hydrogeological information.

Industrial areas are major sources of surface and groundwater pollution. As a result, constant monitoring of water quality is of vital importance to detect pollution incidences in time and to take corrective actions. This integrated hydrogeological, hydrochemical and environmental isotopes (?2H, ?18O, 3H) study has been undertaken to investigate the hydrogeological conditions around the Kusile coal-fired power station located in the quaternary catchment B20F. The study area is characterized by mainly weathered and fractured and fractured aquifer systems.