Groundwater resources decline in apennine mountain areas (central Italy): climate change or hidden consumer?

STUDY REGIONSibillini Mountains, central Italy. STUDY FOCUSThe study aims to investigate the role of intensive forest growth, which began around the middle of the 20th century, in the decline of groundwater resources. The method, based on the crop evapotranspiration, considers different land use categories and their areal changes over time. Two model approaches, one of which also considers snow storage and melting, were used to quantify the impact of forest cover on groundwater recharge in the study area. NEW HYDROLOGICAL INSIGHTS FOR THE REGIONFew studies have assessed the impact of forest growth on groundwater resources in mountain areas, mainly due to the difficulty of estimating crop coefficients in this type of contexts. The modelling experiment suggests for the first time in the Italian Apennine ridges (Sibillini Mountains) that forest growth over the last 70 years has negatively impacted the availability of groundwater resources by reducing groundwater recharge; specifically, the analysis performed during the period 1995-2015 (i.e., after the forest growth) within one spring catchment yielded values of annual water loss between 2.8% and 6.3% of the annual spring discharge, obtained via a lumped-parameter model and by water budget, respectively. However, the influence of forest growth could be even more significant when considering other parts of the study region. The developed approach is particularly flexible and generally applicable to other contexts.