Spatiotemporal and Hydrogeological Assessment of Groundwater Flow and Vulnerability in Parts of the Benin Formation, Akwa Ibom State, Southeastern Nigeria

Groundwater flow dynamics and vulnerability assessment are critical for sustainable water management in parts of the Benin Formation, Southeastern Nigeria, where groundwater is the primary potable water source. However, uncontrolled exploitation, poor borehole siting, and contamination risks necessitate a detailed understanding of groundwater flow patterns and vulnerability. This study applies geospatial techniques to analyze groundwater flow patterns and assess aquifer vulnerability in parts of the Benin Formation, Southeastern Nigeria. Sustainable groundwater management is crucial due to increasing water demand, uncontrolled borehole siting, and contamination risks. A total of 23 borehole Static Water Level (SWL) measurements, lithologic logs from 11 sites, and Digital Elevation Models (DEMs) were analyzed to model groundwater flow. GIS-based hydrological modeling and vulnerability mapping were applied to assess contamination risk. Results indicate a predominant northwest-to-southeast groundwater flow, influenced by topography, hydraulic gradients, and lithology, with secondary flows towards the Imo and Cross Rivers. Recharge zones were delineated in Oruk Anam, Essien Udim, and Ukanafun, while discharge areas were identified near Ibesikpo Asutan and Ikot Ekpene. Vulnerability mapping reveals higher contamination risks in shallow aquifers within agricultural and industrial zones, necessitating urgent groundwater protection. These findings provide critical insights into groundwater sustainability, emphasizing the need for recharge zone protection, sustainable extraction policies, and pollution control measures to ensure long-term groundwater security.