Assessment of recharge capacity potential of groundwater using comparative multi-criteria decision analysis approaches

Groundwater resources have always been some of the most valuable resources of human settlements. Climate changes and ever-increasing water demands registered in the last century have led to diminishing levels of groundwater reserves, as well as reduced recharging potential. Therefore, in order to use groundwater aquifers in a sustainable manner, it is required to identify areas with higher replenishing potential. The current study addresses the issue of generating a map for identifying differently ranked groundwater recharging potential values, in the aquifers of the Moldavian Plain region, Romania. For the purpose of conducting the analysis, maps were created through GIS based multi-criteria Analytic Hierarchy Process (AHP) and Catastrophe Theory (CT), with seven relevant, thematic, spatial layers: precipitation distribution, lithological strata, soil texture, declivity, drainage density, land use and the distribution of groundwater level tendencies. The results of the two methods of analysis are similar. Prediction differences are of maximum 3%, in the case of extreme classes (very bad and very good) and in the case of middle classes the deviation is not greater than 0.4%. Following the validation of the results generated by the two methods that were applied, it was observed that the predictions offered by CT are more accurate. This aspect can be based on the fact that the main factors that contribute to the prediction are different. This type of workflow emphasizes the necessity of implementing appropriate groundwater management plans for mitigating reservoir scarcity/depletion, and recommending sustainable solutions for future groundwater exploitation practices.