Hydrochemical characteristics of aquifers near Sutherland in the Western Karoo, South Africa

Abstract

The Western Karoo depends entirely on groundwater for domestic and agricultural use. An understanding of the chemical evolution of the groundwater provides insight into the interaction of water with the environment and contributes to better resource management.Descriptive statistics, correlation matrices and factor analysis, together with stable isotope data were used to gain an understanding of the hydrochemical processes of the groundwaters in the fractured rocks around Sutherland in the Western Karoo. The main processes influencing the groundwater chemistry are salinisation, mineral precipitation and dissolution, cation exchange and human activity. The stable isotope data indicate that the infiltration of evaporated water is partly responsible for the occurrence of saline subsurface waters. The ionic, oxygen and hydrogen stable isotope composition of the groundwaters suggests that the effects of localised topography are one of the overriding factors controlling the groundwater chemistry. In higher lying areas, Ca(HCO 3 ) 2 type waters are prevalent, while in topographical flat areas NaCl type waters dominate. In areas where water collects close to or at the surface, saline soils are formed. From these areas salts are leached to the subsurface, during significant recharge periods. These findings are important in that they contribute to the identification of suitable locations for developing groundwater resources that could yield a relatively better quality water. ᭧

Statistical study to identify the key factors governing ground water recharge in the watersheds of the arid Central Asia

“…They account for 87.1 % of the total variance in the dataset. To maximize the variance of the first three principal axes, the Varimax normalized rotation was applied (e.g., Adams et al 2001;Aiuppa et al 2003;Cloutier et al 2008). A descriptive term is defined for each of the three components based on their characteristic loadings (Fig.…”

“…6a, b). Many other regional hydrochemical studies have also produced a first component with high loadings of elements associated to different salinization processes, such as ion-filtration processes (Usunoff and Guzman-Guzman 1989), infiltration of saline surface water (Adams et al 2001), and seawater intrusion or infiltration from salt manufacturing (Wang et al 2007). The significance of the other two components 2 and 3, in terms of regional processes, is not as important as that of the first component 1 as they explain a lower percentage of the variance.…”

Sources of contaminants and groundwater quality in the coastal part of a river delta

“…The pH of groundwater of the study region varies from 6.6 to 8.1 with an average of 7.1 which indicates that the dissolved carbonates are predominantly in bicarbonate form (Adams et al 2001). The EC ranges from 500 to 5,500 lS/cm with a mean value of 1,702 lS/cm.…”

Using Statistical Analysis Approach to Evaluate the Groundwater Quality in Jisser Diyala Area

“…[1] In the last years, multivariate statistical methods were applied for groundwater to extract high concentration from hydrochemical data sets in systems. These methods can give the solution to the hydrological factors like aquifer boundaries, ground water flow paths, or hydrochemical contents [2], identify geochemical controls on composition [3], and fell apart anomalies like artificial impacts from the background on a variety of scales [4]. These studies often use either or both R-mode (source of variation in a dataset from parameters) or Q mode (variation between samples) multivariate techniques [5].…”