Parametric and numerical approaches to assess groundwater vulnerability to pollution in alluvial areas.

Industrial and agricultural activities represent the main causes of decaying of hydro-chemical quality of groundwater, which represents the most important source of drinking water in developed countries. Thus, assessing of groundwater vulnerability is a crucial aspect for land management aimed at the safeguard of groundwater resources, because expressing the potential impact of pollutants, depending on hydrogeological conditions and processes occurring in the unsaturated and saturated zones. In the framework of the Horizon 2020 LandSupport project, the study presented here contributed to implement tools for a geoSpatial DSS (S-DSS) dedicated to groundwater vulnerability assessment. For such scope, the study is specifically focused on estimating groundwater vulnerability to pollution of shallow aquifers where agricultural and livestock productions cause a very high risk of groundwater pollution. The goal was to estimate and map intrinsic aquifer vulnerability to generic pollutants of representative shallow alluvial aquifer characterizing the Marchfeld region (northeast of Vienna, Austria). To reach the achievement, three different approaches were used: a parametric method, i.e., the SINTACS-R5, a transfer function approach, i.e., the TFM model and, a process-based numerical model, the Flow-Hages model. Specifically: the SINTACS method was applied to estimate intrinsic groundwater vulnerability of the shallow alluvial aquifers characterizing the area; TFM method was applied for the assessment of the mean travel times of a generic non-reactive pollutant, considering a grass cover, through the unsaturated zone till the water table depth; finally, considering the same generic non-reactive pollutant and a grass cover, the Flow-Hages model allowed to simulate the output breakthrough curves, evaluating the time arrival of the peak at the groundwater table depth.