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Drought is a normal and recurrent climate feature, but one of the most important climate hazards that can produce negative effects on natural and socioeconomic systems. The northern part of Italy is historically rich in water resources and a very fertile and productive area. Recently, however, drought events increased their influence on the hydrological behaviour of the main rivers in this region. In this work, we analyse the spatial distribution of drought events and their effects on vegetation greenness in northern Italy during the 2000–2020 period, using MODIS images at 1 km spatial resolution. Correlation maps between fields of bi‐weekly vegetation indices (normalized difference vegetation index [NDVI] and enhanced vegetation index [EVI]) and drought indices (standardized precipitation index [SPI] and standardized precipitation evapotranspiration index [SPEI]) were estimated. To generate the SPEI index, 150 daily precipitation and temperature ground station series were collected, aggregated at bi‐weekly scale, reconstructed, homogenized and spatialized at 1 km resolution by mean of Universal Kriging with auxiliary variables. The NDVI and EVI indices (MOD13A2) and the land surface temperature (LST; MOD11A2) were collected from MODIS images and quality checked, removing pixels with clouds and low‐quality data. Drought events were detected by means of the SPEI and SPI at medium (12‐months) and long (24 and 36 months) timescales. The events were characterized by drought intensity, duration and percentage of affected area. For each pixel, the Pearson's correlation between NDVI/EVI and SPEI/SPI at different timescales was estimated. On the basis of the correlation maps and the CORINE Land Cover 2020 (MCD12Q1), we estimated the drought impact on different vegetation types as the percentage of vegetation undergoing drought stress. The investigation on drought indices has revealed nine main summer and spring events in the study period. The events of summer 2003 and 2017 were especially remarkable, with respectively 50% and 40% of the total area under drought according to the SPEI index at 12 months. The correlation between drought and vegetation indices revealed that in the Po Valley and Tuscan hills, the vegetation communities perturbed by agriculture are those that are most affected by droughts, with 13% of vegetation under drought on long timescales. This study also indicated that in the last two decades, the main trigger of droughts in northern Italy was the lack of precipitation rather than pure temperature increase. [ABSTRACT FROM AUTHOR]

In the context of climate change, the correct management of groundwater, which is strategic for meeting water needs, becomes essential. Groundwater modeling is particularly crucial for the sustainable and efficient management of groundwater. This manuscript provides different types of modeling according to data availability and features of three porous aquifer systems in Italy (Empoli, Magra, and Brenta systems). The models calibrated on robust time series enabled the performing of forecast simulations capable of representing the quantitative and qualitative response to expected climate regimes. For the Empoli aquifer, the process-based models highlighted the system's ability to mitigate the effects of dry climate conditions thanks to its storage capability. The data-driven models concerning the Brenta foothill aquifer pointed out the high sensitivity of the system to climate extremes, thus suggesting the need for specific water management actions. The integrated data-driven/process-based approach developed for the Magra Valley aquifer remarked that the water quantity and quality effects are tied to certain boundary conditions over dry climate periods. This work shows that, for groundwater modeling, the choice of the suitable approach is mandatory, and it mainly depends on the specific aquifer features that result in different ways to be sensitive to climate. This manuscript also provides a novel outcome involving the integrated approach wherein it is a very efficient tool for forecasting modeling when boundary conditions, which significantly affect the behavior of such systems, are subjected to evolve under expected climate scenarios. [ABSTRACT FROM AUTHOR]

Salinization is a main concern for coastal aquifers due to climate change and incremental anthropogenic pressure. The Mediterranean area is particularly sensitive to this process, being several coastal aquifers already affected by seawater intrusion. The Fano coastal aquifer, located in the northern part of the Adriatic Sea (Italy), has a regional importance since it supplies drinkable water to the local communities and may be subjected to salinization given its intrinsic vulnerability and the awaited human and climate pressure. In this work, for the first time a detailed hydrogeochemical and isotopic study on the Fano shallow aquifer is presented to highlight the quality of this groundwater system. The hydrological, geochemical and isotopic data indicate a strong nitrate contamination in the central part of the basin, forcing the local water management company to inject low-NO 3 waters from the main river course (Metauro River) to reduce the impact due to the N-bearing species. Differently from other coastal aquifers located along the Adriatic Sea where the seawater wedge is deteriorating most groundwater systems, our results and geochemical modeling suggest that the shallow aquifer of Fano is not apparently affected by salinization. This achievement makes this aquifer suitable for assessing whether the groundwater system might be evolving toward a seawater-contaminated aquifer. According to the proposed hydrogeochemical conceptual model, a monitor network should be deployed by the local authorities and the water management company to take appropriate measures to minimize the risk of seawater intrusion, should the hydrogeochemical and isotopic parameters indicate an incipient ingression of seawater. [Display omitted] • The Fano (central-eastern Italy) shallow coastal aquifer in the Mediterranean panorama. • Hydrogeochemistry and isotopes to define salinization and anthropogenic pressure. • Nitrate contamination is minimized by injecting surface water into the aquifer. • Conceptual hydrogeochemical modelling for steering preventive actions. • The Fano aquifer is ideal to investigate short-to-medium term salinization processes. [ABSTRACT FROM AUTHOR]