A SINTACS GIS-based method for assessing groundwater vulnerability in sedimentary aquifers, South-Eastern, Nigeria

Groundwater vulnerability is an ardent problem all over the globe owing to the degradation of groundwater level and rising pollution which presents grievous adverse threat to the ecosystem. To determine this threat, comprehensive research has been conducted to examine the groundwater vulnerability by using several approaches. Broadly, the process-based approach, statistical analysis, and overlay index approaches are utilized in this regard. SINTACS method is one type of process-based and overlay index methods for vulnerability appraisal. This research represents a SINTACS model using applications of the Geographic Information System (GIS) techniques for groundwater vulnerability appraisal. According to the present SINTACS model, the study area surrounded high, moderate, and low zones of potential contamination with area occupy 20.41%, 71.6%, and 7.99%, respectively. The high potential contamination is majorly impacted by combined contributions of thematic layers viz., impact of the vadose zone, aquifer media, topography and net recharge. Nitrate concentrations analysis in some selected boreholes were compared with the SINTACS model to examine its accuracy. The validation rate of the present SINTACS model attains more than 65%, which is an evidence of a satisfactory modeling method. The SINTACS approach demonstrated its versatility even in this complicated hydrogeological setting.