期刊名称：Journal of Environmental Hydrology (ältere Jahrgänge)
印刷版ISSN：1058-3912
电子版ISSN：1996-7918
出版年度：2006
卷号：14
出版社：IAEH
摘要：The groundwater chemistry of Khartoum State between longitudes 32º 15’ - 33º 00’E and
latitudes 15º 10’ - 16º 00’N was evaluated and assessed using different hydrogeological
methods. Groundwater in the region occurs in two hydraulically interconnected aquifers: the
siliciclastic sediments of the Cretaceous Omdurman Formation and the mostly unconsolidated
sediments of the Cretaceous-Tertiary-Quaternary Umm Ruwaba Formation. The analysis of
the flow system indicated a regional flow direction towards the northwest, with a local flow
regime towards the east. Assessment of groundwater chemistry showed negative correlation
between the exchangeable ions, Na-Ca. This means an ion exchange process is active. The
strong correlations between Na+ and Cl
-
ions, TDS and EC indicate that salinization is related
to the increase of concentration of these ions. Dissolution of evaporites is suggested by positive
correlations between Ca, Mg and SO4. Groundwaters were classified into three hydrochemical
facies, Ca-Mg-HCO3, Ca-SO4-HCO3 and Na-Ca-SO4-Cl. The spatial distribution of these
facies and hydrochemical sections indicates that the anionic facies changes in the flow
direction from HCO3 to SO4 and finally to Cl. The cationic facies is mostly affected by the ion-
exchange process of calcium and magnesium by sodium. Mixing is an active process that has
affected the water facies in the region
