Quantifying the Parameters Impact in Groundwater Vulnerability Assessment for Agricultural Pollution, a Review

This study presents a systematic review aimed at evaluating the rating schemes of modified groundwater vulnerability assessment methods, with the objective of identifying the most influential parameters and supporting mitigation strategies to reduce groundwater pressures arising from population growth, agricultural practices, industrial activities, and environmental hazards. The results confirmed that the DRASTIC methodology is the most widely used and modified approach worldwide. Parameters frequency and weights were collected and then screened using simple statistical indicators such as median and mean to properly rank their overall importance. Amongst the most widely used parameters, those representing a physical value, such as groundwater depth, morphology, recharge and hydraulic conductivity, resulted to be the most influential; while nominal parameters, such as the vadose zone, aquifer media, and soil texture, had the least effect in modified application. These differences from the standard DRASTIC approach reflect the focus of recent study on specific vulnerability to agricultural leaching and highlight the need to reconsider the weighting system when focusing on specific vulnerability. Finally, a multi-criteria decision analysis (MCDA) supported by the results of the systematic review was used to rank the most impactful parameters and assess their weight. The results confirmed that more than 70% of overall groundwater vulnerability depends on only three parameters: depth to water, recharge and morphology. These findings provide the foundation for developing more accurate and transferable methodology for evaluate the specific vulnerability assessment to agricultural leaching in porous aquifers.