ASSESSMENT OF GROUNDWATER POTENTIAL ZONES USING GIS AND AHP TECHNIQUES IN OSOGBO, OSUN STATE, NIGERIA

Purpose: Globally, groundwater is a crucial resource for human survival. Supporting diverse anthropogenic activities such as agriculture, domestic use, industrial use, and recreational use. for a sustainable groundwater supply, there is a need to identify areas with high and low groundwater prospects.
Design/methodology/approach: This study utilized the combination of Remote Sensing (RS), Geographic Information System (GIS), and Analytic Hierarchy Process (AHP) techniques to delineate groundwater potential zones (GWPZ) in Osogbo, Osun State, Nigeria. Thematic maps for groundwater influencing factors were generated using Remote Sensing and GIS techniques. Weight was assigned to each groundwater influencing factors in accordance to their importance using AHP approach. The combined thematic maps in ArcGIS generated a groundwater potential zones map.
Findings: The results showed that most high and moderate groundwater potential areas were found in the central and eastern parts of the study area and are the most viable for groundwater exploitation in the study area. The map showed the needed information and the zones were classified into five categories: very low GWPZ is 4.7km² (3.3%), low GWPZ is 28.2km² (19.8%), moderate GWPZ is 74.9km² (52.5%), High GWPZ is 34.8km² (24.4%), and very high GWPZ is 0.1km² (0.1%).
Research limitations/Implications: This study relied on secondary datasets which may not fully capture real-time variations in groundwater dynamic. And extensive validation of the groundwater potential zones could not be carried out due to limited boreholes yield records.
Practical Implications: It is recommended that delineation of groundwater potential zones should be adopted to provide scientific basis for stakeholders, agencies and policy makers to ensure Osogbo Metropolis secure reliable freshwater reserves and minimized unnecessary drilling in low-yield areas and reducing financial losses associated with failed boreholes.
Originality/value: This study revealed efficient and effective techniques for delineating and mapping groundwater potential zones for planning, decision-making for optimal utilization of groundwater and water resources management in Osogbo Metropolis.