Abstract
The scarcity of fresh water resources is a major challenge facing Saudi Arabia. Groundwater is the major conventional water source in Saudi Arabia. Therefore, it is important to identify areas having groundwater potential; however, the current methods of groundwater exploration consume a lot of time and money. Alternatively, this paper introduces a methodology to identify groundwater potential zones in the Central part of Saudi Arabia using remote sensing and GIS-based decision support system (DSS) and fuzzy logic based spatial model. The DSS model generated suitability maps for groundwater potential (GWP) zones with five suitability classes, i.e. excellent, very good, good, poor, and very poor based on the integration of nine thematic maps: soil type, land cover and land use, slope, lithology, rainfall, geological structure, geomorphology, lineament density, and drainage density using a hierarchical process analysis (AHP). The spatial distribution of the GWP zones by AHP-DSS and fuzzy logic model showed that "excellent" suitable areas for GWP were concentrated in the main wadi channels within the central, northeastern and southeastern parts of the study area. The AHP-DSS model showed that 1.47 % (5608.5 km (super 2) ) and 4.15 % (15,787.3 km (super 2) ) of the study area was classified as excellent and very good, respectively, while 12.59 % (47,911.1 km (super 2) ), 74.82 % (284,670.9 km (super 2) ) and 6.97 % (26,519.9 km (super 2) ) of the area were classified as good, poor and very poor, respectively. On the other hand, integrating thematic layers using fuzzy logics indicates that 2.8 % (10,739 km (super 2) ), 8.8 % (33,587 km (super 2) ), 7.9 % (30,106 km (super 2) ), 60 % (228,361 km (super 2) ), and 20.4 % (77,705 km (super 2) ) of the entire study area is considered as excellent, very good, good, poor, and very poor areas for groundwater potential, respectively. The majority of the areas with excellent to very good suitability had slopes between 0 and 3 % and were in intensively cultivated fields. The major soil type in the excellent to very good zones was Arenosols and Lithosols. The rainfall ranged from 125 to 226 mm/year, while the main lithological structures are alluvial deposits, carbonate rocks, and mixed sedimentary consolidated rocks. These areas are mainly located in the carbonate-sulfate formations, which extend from the Lower Jurassic to the Lower Cretaceous and the sandstone aquifers. Moreover, they have lineament density ranged from 4.75 to 8.34 km/km (super 2) , and drainage density ranged from 1 to 1.83 km/km (super 2) . Furthermore, the study revealed that lineament density is closely related to groundwater occurrence and yield and is essential to groundwater surveys, development, and management. Validation of the two models employed depends on comparing existing groundwater well locations with the suitability map generated using the proximity analysis tools of ArcGIS 10.2. The results obtained from AHP-DSS approach and fuzzy model were verified with field survey and were found to be in very good and good agreement, respectively. The validation results showed that the database and methodology used for developing the suitability model for GWP zones, including the suitability levels of the criteria and the criteria's relative importance weights, to have yielded accurate results. Copyright 2016 Springer-Verlag Berlin Heidelberg