Impact of Soil Coverings and Land Cover Types on Groundwater Recharge in Karst Aquifers of Southern Italy

In southern Italy, particularly in the Campania region, karst aquifers are characterized by unusual surficial geological conditions due to the widespread occurrence of a soil mantle, mainly of ash-fall pyroclastic origin and the development of related land cover types. These features play a significant role on hydrological processes controlling groundwater recharge, which until now has been generally oversimplified and underestimated. In such a view, coupled soil hydrological monitoring and modeling approaches are presented in this work in order to enhance the understanding of groundwater recharge processes in two representative karst aquifers of the Campania region, selected due to their geomorphological settings and variability of soil cover and vegetation types. Based on field and laboratory characterizations of the soil mantle, the spatial and temporal variability of groundwater recharge was estimated applying the Soil Water Balance (SWB) code. Among the principal outcomes, different depths of the evapotranspiration zone and variable values of Available Soil Water Depth (ASWD) were observed for each land cover class. Groundwater recharge rates were found to be reliant on the land cover type and soil thickness, showing lower values for wooded areas and higher for grassy ones. Based on the comparison of the results achieved, this research advances the knowledge about methods for the assessment of groundwater recharge in karst aquifers which can be conceived as useful in the perspective of improving water resources planning under the expected impacts of climate change.