Authors:
Mashal Al-Fawwaz;
Abstract:
In this study, the geological structures in the area extending between Ghabawi solid waste and Swaqa
hazardous waste deposits were investigated in detail to study the impacts of human activities on the aquifer
vulnerability. Two indices were used to evaluate that vulnerability, namely; DRASTIC and SINTACS. The
hazardous waste disposal site of Swaqa in the southern part of the study area, the landfill deposit in its
northern part and the intended oil shale and uranium mining are the main sources of potential groundwater
pollution. The study aims at building a new approach to combine structures with known vulnerability indices
to better evaluate the prevailing conditions. Chemical analyses of the groundwater quality in the area were
performed to validate the findings. All relevant variables of the study area were put in a GIS environment as
digits to ease layering of the different types of spatial data.
The aquifers in the study area refer to the Lower Tertiary and Upper Cretaceous and are composed mainly of
carbonate types of rocks. Three major structures are found in the area consisting of faults differently trending
in directions. These faults were found to intersect the aquifers in the area. Without the consideration of the
effects of the faults, the area would locate in middle vulnerability zones, but their presence caused an
elevation in the vulnerability class. This was clear from the spatial distribution of the values of nitrates, which
was found to correlate with the structural map of the area.
DRASTIC and SINTACS vulnerability indices are unable alone to evaluate the spatial vulnerability of the
aquifers when geologic structures are dominant. Accordingly, some modifications and merging were made to
the DRASTIC and SINTACS indices to account for the structures in order to make thse indices suitable to
evaluate similar areas with prevailing geologic structures, especially faults and fissures.
Keywords:
Swaqa, Ghabawi, Geologic structures, Vulnerability of groundwater, DRASTIC, SINTACS