Hydrogeological Investigations of Groundwater and Surface Water Interactions in the Berg River Catchment, Western Cape, South Africa

Abstract

The Berg River Catchment based in the Western Cape Province, South Africa services the greater Cape Town area with water, subsequent to supplying the vast agricultural activities that exist in the middle and the lower reaches. This study thus investigates the hydrogeochemical interactions between surface and groundwater in the Berg River Catchment with the aim of establishing trends and transfer of constituents between the surface and groundwater systems, investigates the role that geology plays in water chemistry as well as identifies the geochemical processes controlling surface and groundwater chemistry in the catchment. This study was carried out using three types of research designs namely i) experimental research design; ii) field research design and meta-analysis research design. Furthermore, the study made use of hydrochemical data ranging from 2003 to 2013 obtained from the National Water Monitoring Database owned and maintained by the Department of Water and Sanitation and data that were sampled in 2016 by authors and analyzed using the ICP-MS Technique Ground Water Chart, Arc-GIS and Geosoft (Oasis Montaj) were further employed to model the data. The results indicated that: i) in the Upper Berg there is not much interaction and transfer of constituents between surface and groundwater; ii) the Middle Berg, however, indicated a degree of interaction with the sharing of constituents between the two water systems and iii) the Lower Berg indicated only NaCl water type also noting that the area situated near the river mouth whereby there is the mixing of river and seawater.