This work reports the results of a hydrogeological investigation carried out on the volcanic Vulsino area (Central Italy). In this area there is an important regional aquifer, which feeds the Bolsena Lake (average surface area of about 114 km2). The volcanic aquifer is made up of alternated lava and pyroclastic deposits, laid over low permeability Pliocene and Pleistocene marine and brackish-marine sediments. The north-eastern part of the Vulsino area has been, in the last twenty years, the focus of several geological and hydrogeological investigations, as it is a key resource of drinking water. On the base of new geological and hydrogeological information, a review of the hydrogeological budget of the Bolsena Lake was made. Results suggest the adoption of new water management strategies in order to avoid worsening the environmental situation, deriving from the ongoing climatic variations and the increase of anthropic pressure. Indeed, the analysis of the rainfall trends of two meteorological stations having a continuous set of data show a statistically significant decrease in rainfall, of approximately 3-4 mm/year (1921-2007 period). These trends are consistent with those in many other localities of Central Italy. The reduction in rainfall coupled with the amount of water pumped from wells produced a reduction in the discharge in the outlet of Bolsena Lake. The available piezometric data, and geoelectric investigations, show that the position of the groundwater divide in the north-western sector is related to the recharge and to the rate of pumping, while in the north-eastern area it is almost stable. This is due to the geological and structural set up of the area (i.e. presence of faults associated with the caldera structure of Bolsena Lake). The results of these investigations will be useful in minimising the impact of the occurring climatic change and for rational management of the water resources.

Management of complex aquifers in times of climatic change: the case of the volcanic Vulsino aquifer (Central Italy)

DI MATTEO, Lucio;DRAGONI, Valter Ulderico;GIONTELLA, CECILIA;
2008

Abstract

This work reports the results of a hydrogeological investigation carried out on the volcanic Vulsino area (Central Italy). In this area there is an important regional aquifer, which feeds the Bolsena Lake (average surface area of about 114 km2). The volcanic aquifer is made up of alternated lava and pyroclastic deposits, laid over low permeability Pliocene and Pleistocene marine and brackish-marine sediments. The north-eastern part of the Vulsino area has been, in the last twenty years, the focus of several geological and hydrogeological investigations, as it is a key resource of drinking water. On the base of new geological and hydrogeological information, a review of the hydrogeological budget of the Bolsena Lake was made. Results suggest the adoption of new water management strategies in order to avoid worsening the environmental situation, deriving from the ongoing climatic variations and the increase of anthropic pressure. Indeed, the analysis of the rainfall trends of two meteorological stations having a continuous set of data show a statistically significant decrease in rainfall, of approximately 3-4 mm/year (1921-2007 period). These trends are consistent with those in many other localities of Central Italy. The reduction in rainfall coupled with the amount of water pumped from wells produced a reduction in the discharge in the outlet of Bolsena Lake. The available piezometric data, and geoelectric investigations, show that the position of the groundwater divide in the north-western sector is related to the recharge and to the rate of pumping, while in the north-eastern area it is almost stable. This is due to the geological and structural set up of the area (i.e. presence of faults associated with the caldera structure of Bolsena Lake). The results of these investigations will be useful in minimising the impact of the occurring climatic change and for rational management of the water resources.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11391/35706
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