Climate change effect on groundwater resources in Emilia-Romagna region: An improved assessment through NISTOR-CEGW method

A ′New Implemented Spatial-Temporal On Regions–Climate Effect on Groundwater’ approach has been developed in the present work to assess the impact of climate on groundwater resources in Emilia-Romagna region. The assessment used in this paper is based on effective precipitation and De Martonne Aridity Index, both of them analyzed in three time periods (past, present, and future) using the spatial distribution of these parameters at a regional scale. In addition, the actual crop evapotranspiration using the Budyko method has completed to incorporate the land cover contribution at the evapotranspiration phenomena and further, the effective precipitation pattern was subtracted and defined for the Emilia-Romagna region. The examination of the actual crop evapotranspiration during the three periods show a slight decrease in the maximum values, from 817 mm (in the past) to 762 mm (in the present) and 751 mm (in the future). There was a decrease in the maximum effective precipitation between past and present from 2263 mm to 1922 mm, while for the future the effective precipitation indicates values which reach 1885 mm. The De Martonne Aridity Index indicates a significant decrease during the past (24.8–140.5), present (21.8–136.8), and future (20.5–127.1). These descending values suggest the aridization of the Emilia-Romagna in the northern, eastern, and central sides, where the index values fall below 28 and where the sub-humid and Mediterranean climates were identified. In order to assess the climate change effect on groundwater resources, an improved method based on inference matrix tool was proposed to combine the climate index and the effective precipitation parameter at spatial scale. Through this approach, the very high and high impact of climate change on groundwater resources were verified during all the three periods in the North and Northeast parts of the region, whereas the low impact was verified more in the South and the West sides. Moreover, the spatial distribution of the problematic areas extends in the present and future period.