كلية النفط والمعادن
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Item HYDROCHEMISTRYOF GROUNDWATER IN KHARTOUM STATE CENTRAL SUDAN(ALNEELAIN UNIVERSITY, 2002-02) Hussien Salim AwadAbstract The groundwater chemistry of Khartoum State between longitudes 32° 00'-33° 0O’E and latitudes 15° O0’-16° 00'N was evaluated and assessed using different hydrogeological methods. Groxmdwater in the region occurs in two hydraulically interconnected aquifers. The siliciclastic sediments of the Cretaceous Omdurman Formation form the lower one, and the mostly unconsolidated sediments of the Cretaceous-Tertiary- Quaternary Umm Ruwaba Formation comprise the upper one. The evaluated hydrodynamic properties revealed unconfined conditions in most parts of the aquifers system and partial confinement in some parts, where clayey zones occur. The analysis of flow system indicated a regional flow direction towards the northwest, with a local flow regime towards the east. Preliminary assessment of grormdwater chemistry was investigated by using different statistical technique such as X-Y plots, correlation, cluster, principle components, and factor analyses. The results of analyzing data by these techniques showed negative correlation between the exchangeable ions, Na-Ca and Na-Mg, which means ion exchange process is active. The strong correlations among Na’ and Cl‘ ions, TDS and EC indicate that salinization is related to the increase of concentration of these ions. Dissolution process of evaporitic mineral is suggested by the strong positive correlations between Ca”, Mg” and SO42" Groundwaters were classified by -grouping them‘ into faeies~ For ~the—purpose of -classification, the pattern diagram of Lee, trilinear plots of Hill-Piper, Durov and by Chadha diagram. Three main types of hydrochemical facies were recognized, Ca-Mg-HCO,, Ca-SO,-HCO, and Na-Ca-S04-Cl. The spatial distribution of these facies and hydrochemical sections, indicate that the anionic facies changes in the flow direction from HCO,’ to SO42’ and finely to Cll. The cationic facies is mostly affected by ion-exchange process of calcium and magnesium by sodium. Mixing is an important and active process that has affected the water facies in the region. The saturation state of groundwater showed that, it is saturated with respect to carbonate minerals and undersaturated with respect to CO2 and sulphate. Assessment of groundwater quality at different locations indicated its suitability for all purposes except at few specified localities.Item APPLICATIONS OF REMOTE SENSING AND GIS IN GROUNDWATER RESOURCES ASSESSMENT AND DEVELOPMENT CASE STUDY, GEDAREF STATE, EASTERN SUDAN(Neelain University, 2012) Basheer Ahmed Elubid EasiaABSTRACT The study area lies in Gedaref State in the eastern Sudan, the area suffers from acute shortage of water supply especially during summer seasons, due to the over exploitation of groundwater and the high rate of runoff as a result of clayey overburden and relatively high slopes. Integrated methods of Remote Sensing (RS) and Geographic Information System (GIS), geological, geophysical and hydrogeological investigations have been carried out to assess and develop the water resource in the area under consideration. Remotely sensed data of the Landsat 7 ETM+ multi-spectral images and SRTM (Shuttle Radar Topographic Mission) interferometry elevation data have been used in this study. Different digital image processing techniques were applied to the satellite images to reveal the geological, structural, hydrogeological, and hydrological aspects. The enhanced imageries had been pre-processed by new technique of vegetation suppression in order to minimize the masking effect of vegetation spectra over the geological ones. DEM (Digital Elevation Model) derived from SRTM data is used to delineate the hydrological catchment areas and the major lineaments. Nine sub-basins have been delineated with their hydrological aspects, where River Atbara and Abu Fargha sub-basins are the largest sub-watershed in the Gedaref area. Lineaments have been spatially and structurally analyzed, which revealed that most fractured basaltic and sandstone aquifers lie in tensional fractures zones related to the formation of Gedaref basin, whereas in basement terrains the fractures were classified based on the paleao - stresses during old geological events. The electrical geophysical methods identify three main aquifer types, sandstone, fractured basalts, and the unconsolidated superficial aquifers. The thickness of sandstone aquifer extends between 47 m to 150 m, where the groundwater occur at depths range from 30 m to more than 100 m blow surface. The sandstone aquifer parameters were calculated from pumping tests revealed that the average transmissivity is about 280 m2 day"', whereas the average hydraulic conductivity is 0.75m day", and the storativity varies from 6.3 x 10'2 to 2.0 x 10'7. However, the fractured basaltic aquifers are of average transmissivity values of 100 m2 day'l. l-lydrochemical data disclosed that the total dissolved solids (TDS) varying from 151 to 5210 ppm due to the lithological variations in the study area. Spatial analysis of these data indicates the presence of the highly TDS concentration zones in basaltic terrains. Surface geological investigations coupled with the geophysical data confirmed the presence of a thick widespread clayey layer capping the sandstone and basaltic aquifers, which preventing the infiltration of water to the underling aquifers. A number of fourteen potential dams and eighteen injections wells as artificial recharge facilities have been proposed in order to enhance the groundwater storage based on RS and GIS, geological, hydrological, and structural criteria.