Integrated GIS, Remote Sensing, and Electrical Resistivity Tomography Methods for the Delineation of Groundwater Potential Zones in Sangaw Sub-Basin, Sulaymaniyah, KRG-Iraq

Abstract

In the Sangaw region, groundwater is the primary supply of water for drinking, residential purposes, livestock, and summer farming activities. Therefore, the main objective of this research is to delineate groundwater potential zones (GWPZs) in the Sangaw sub-basin, Sulaymaniyah, KRG-Iraq, by integrating geographic information system (GIS), remote sensing (RS), analytical hierarchy process (AHP), and electrical resistivity tomography (ERT) techniques. Seven different thematic layers, including geology, rainfall, slope, lineament density, land use/land cover, drainage density, and topographic position index, were chosen as the prediction factors. The analytical method of an analytical hierarchy process pair-wise matrix was used to evaluate the normalized weight of these thematic layers. All the layers and their corresponding classes were assigned ranks and weights based on their impact on groundwater potential. Using ArcGIS, these thematic maps were combined to precisely determine the groundwater potential map within the research area. Five different potential zones were generated for the resulting map, namely, very low (55.4 km2), low (90.4 km2), moderate (68.1 km2), high (100 km2), and very high (62.4 km2). The findings revealed that almost 43.2% of the study region is characterized by high to very high groundwater potential zones. In contrast, the very low to low groundwater potential covers around 38.7%, and the moderate groundwater potential occupies 18.1% of the study region. The final map was then validated using results from the two-dimensional inverse sections of eight electrical resistivity tomography profiles. The validation data confirmed that groundwater potential classes strongly overlap with the subsurface water-bearing or non-bearing lithology, and groundwater productivity zones in the given area. The novelty of this research lies in the application of electrical resistivity tomography validation to the groundwater potential mapping approach, which illustrates the robustness of the overall methodology for data-scarce areas. Furthermore, this is one of the very few groundwater potential studies in Iraq and the first in the Sangaw sub-basin, which can assist decision-makers with groundwater prospecting and management, and enable further exploration in the region.