Analytical Hierarchical Process (AHP) Techniques and Geospatial Technologies for Groundwater Potential Zone Mapping

Abstract

Due to its consistent availability, acceptable natural quality, and ease of direct diversion to the underprivileged population, groundwater is a vital source of water supply. It can also be transported there more swiftly and inexpensively. Exploring groundwater potential zones (GWPZs) maps is therefore essential, especially in semi-arid environments with insufficient surface water supplies. The groundwater potential of the research area is assessed using geographic information system methods and remote sensing data. Operational Land Imager 8 data, digital elevation models, soil data, rainfall data, and dug-out-well data were utilized to estimate the characteristics that influence groundwater potential and recharge zones.  Maps of lineament density, drainage density, rainfall distribution, topographic-wetness index, land use/land cover, land-surface temperature, slope and soil were produced. These were overlaid based on analytical hierarchical process weightage prioritization at a constituency ratio of 0.05. The resulting map was divided into very high, high, moderate, low and very low groundwater potential zones. The area dimensions of these categories are 116005.5 ha, 35822.4 ha, 20152 ha, 2459 ha and 259245 respectively. Accordingly, the north-east part of the study area is expected to have very high ground‐water potential. Out of the 55 operational wells sampled, 72.73 % were situated in areas with very high groundwater potential. The high category had 10.91% while the moderate, low and very low categories remained 7.27%, 5.45% and 3.64% respectively. The overall result indicates that the model approach is reliable and can be adopted for a reliable characterization of GWPZs in any semi-arid/ arid environment.