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Abstract
Tectonically, the western region of Saudi Arabia is the eastern part of the rifted Nubian Shield that is known as Arabian Shield mainly comprising of the Precambrian to the Achaean rocks. Development of the alluvial cover or the younger sedimentary rocks is poor. In this part of the country, the main sources of water supplies are the desalination of seawater, the groundwater yielded from poorly developed thin alluvial deposits within different seasonal river (Wadi) channels and the recycled water. In spite of all efforts to improve the water supplies from these sources, the ‘water demand’ of Jeddah-Makkah and the allied urban centers is not adequately satisfied mainly because of ever growing urbanisational activities, drastic change in the lifestyle and the rapid increase in pilgrimers for Umra & Hajj. No serious attempt has so far been done to explore additional water potential from the crystalline rocks of the Arabian Shield. Direct identification of the prospective “hotspots” in crystalline shield areas is a difficult task in exploration as the exploitable water saturation is associated with the complex fault/fracture zone(s) or the weathered zones, which are generally concealed beneath the alluvial cover, thin weathered layers or the younger basalt-flows. During present study, the remote sensing analytical technique has been adopted for Identification of the offshore submarine groundwater springs along the selected coastal areas of the eastern Red Sea, which could be helpful for locating the buried pathways of groundwater discharging through the fault/fracture zone(s) from the Makkah-Jeddah-Taif land region. Preliminary remote sensing study using the Landsat7 ETM+ satellite images shows the possible presence of the groundwater discharges in the target area. The anomalous spots were observed spreading over a vast offshore area, which seem to be the manifestations of the flows of water originated on land and end up in the sea, just as rivers do – only they take a subterranean route to their destinations into the sea as invisible rivers. Based on the literature research, it is inferred that the tectonic setting of the western coast of Saudi Arabia shows favourable conditions for such phenomina. The apparent extent and amount of the groundwater arrested within the seawater indicate that the groundwater-flow has high hydraulic gradient, high secondary permeability & porosity of the crystalline rocks, and relatively longer transport pathway from a recharge area to a discharge area. A multi-disciplinary research project is in progress for the detailed remote sensing modeling of the offshore and the on-land tectonic structures controlling the groundwater potential in the region.
Writer
Nayyer Alam Zaigham, Omar Siraj Aburizaiza, Zeeshan Alam Nayyer, Gohar Ali Mehar, Azhar Siddiq and Sabahat Noor
Nayyer Alam Zaigham, Omar Siraj Aburizaiza, Zeeshan Alam Nayyer,
Gohar Ali Mehar, Azhar Siddiq and Sabahat Noor
Unit for Ain Zubaida Rehabilitation & Groundwater Research,
King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
