Groundwater is a vital source of fresh water in many areas of the Mediterranean Basin and it will become increasingly important due to climate change and the resulting intensification in water scarcity. The Salento peninsula (Puglia region) in southern Italy is no exception, where groundwater is the main source mostly for drinking and irrigation purposes. In fact, the karst nature of the Salento territory allows the presence of groundwater resources rather than surface water resources. The recharge conditions of this aquifer are very complex since its geological and hydrogeological structures are complex. In addition to this, the scarcity of data prevents to understand all the phenomena as a whole and to setup integrated surface/groundwater models that could be useful for investigating the impacts of climate change on the Salento groundwater resources. However, for the Salento area, a direct correlation between hydrological variables (precipitation and temperature) and groundwater levels (GWLs) has been shown. In particular, despite the complexity of the aquifer, it is possible to define potential linear relationships between observed meteorological indices, such as the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), and GWLs collected in monitoring wells. In most cases, there are high correlation coefficients between SPI/SPEI and GWLs for long accumulation periods of the climate variables, in the order of 18 months. This, for the aquifer studied, reflects the attenuated response of groundwater to precipitation/precipitation-evapotranspiration signals. In this work, we use future projections of SPIs and SPEIs for the Salento area to estimate the possible impacts of climate change on the groundwater resource. In particular, for this study, we computed SPI and SPEI projections, until the end of this century, from future precipitation and temperature data of an ensemble of Regional Climate Models (RCMs) of the EURO-CORDEX initiative, under two climate scenarios, namely the RCP4.5 and the RCP8.5. Prior to their use, the raw RCM data were downscaled/bias corrected to properly represent the observed climate in the study area. Under the hypothesis that the observed linear relationships between meteorological indices and GWLs remain valid over time, we obtained future projections of GWLs from the projections of SPIs/SPEIs. The analysis of the future GWLs has been conducted at short-, medium- and long term. The use of an ensemble of climate models allows in evaluating the uncertainty of the results. As long as a high correlation between meteorological indices and GWLs exists, the approach used in this work can be easily applicable to other study areas.
Climate change and future groundwater level projections for the Salento Aquifer (Italy) / D'Oria, Marco; Balacco, Gabriella; Todaro, Valeria; Rosaria Alfio, Maria; Dolores Fidelibus, Maria; Tanda, Maria Giovanna. - (2022). ((Intervento presentato al convegno Sustain Valencia 2022 tenutosi a Valencia nel 6-8 ottobre 2022.
Climate change and future groundwater level projections for the Salento Aquifer (Italy)
Marco D'Oria
;Valeria Todaro;Maria Giovanna Tanda
2022-01-01
Abstract
Groundwater is a vital source of fresh water in many areas of the Mediterranean Basin and it will become increasingly important due to climate change and the resulting intensification in water scarcity. The Salento peninsula (Puglia region) in southern Italy is no exception, where groundwater is the main source mostly for drinking and irrigation purposes. In fact, the karst nature of the Salento territory allows the presence of groundwater resources rather than surface water resources. The recharge conditions of this aquifer are very complex since its geological and hydrogeological structures are complex. In addition to this, the scarcity of data prevents to understand all the phenomena as a whole and to setup integrated surface/groundwater models that could be useful for investigating the impacts of climate change on the Salento groundwater resources. However, for the Salento area, a direct correlation between hydrological variables (precipitation and temperature) and groundwater levels (GWLs) has been shown. In particular, despite the complexity of the aquifer, it is possible to define potential linear relationships between observed meteorological indices, such as the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), and GWLs collected in monitoring wells. In most cases, there are high correlation coefficients between SPI/SPEI and GWLs for long accumulation periods of the climate variables, in the order of 18 months. This, for the aquifer studied, reflects the attenuated response of groundwater to precipitation/precipitation-evapotranspiration signals. In this work, we use future projections of SPIs and SPEIs for the Salento area to estimate the possible impacts of climate change on the groundwater resource. In particular, for this study, we computed SPI and SPEI projections, until the end of this century, from future precipitation and temperature data of an ensemble of Regional Climate Models (RCMs) of the EURO-CORDEX initiative, under two climate scenarios, namely the RCP4.5 and the RCP8.5. Prior to their use, the raw RCM data were downscaled/bias corrected to properly represent the observed climate in the study area. Under the hypothesis that the observed linear relationships between meteorological indices and GWLs remain valid over time, we obtained future projections of GWLs from the projections of SPIs/SPEIs. The analysis of the future GWLs has been conducted at short-, medium- and long term. The use of an ensemble of climate models allows in evaluating the uncertainty of the results. As long as a high correlation between meteorological indices and GWLs exists, the approach used in this work can be easily applicable to other study areas.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.