Hydrochemistry of groundwater at Omdurman area Khatoum state, Sudan

The hydrochemistry of water samples have been used to identify the chemical characteristics of groundwater in Omdurman area. Water samples in the project area were chemically analyzed for major cations and anions at the laboratory by the standard analytical procedures. GIS technique was used to construct water sample location sites and Rockwork software for lithostratigraphic cross-sections. Chemical data were manipulated using Piper diagram for chemical facies and SPSS software for statistical analyses such as basic statistics (mean and standard deviation) and Spearman's correlation matrix. Generally the chemistry of the groundwater in relation to physical parameters and major ions (cations and anions) visualizes increase of concentrations to the south and south-west of the study area. Based on Hill-Piper trilinear diagram, four chemical water types were observed: Na-Ca - CO₃ - facies; Ca-Mg-HCO₃ - facies, Na-Mg-Ca-HCO₃-Cl- facies and Na- Cl-HCO₃-SO₄ facies, forming the dominant water types in the area. The relationship between EC and TDS is highly significant (r = 0.82). Salinity variations are mainly controlled by sodium, chloride and Sulfate concentrations. The groundwater geochemistry is governed mainly by the dissolution of silicate minerals (plagioclase and montmorillonite) and carbonates (calcareous cementing material) as well as ion exchange of cations.