Since many years, the seawater intrusion is involving wide areas of the Italian coastal plains. The knowledge of this phenomenon is basic in managing and protection of the water resource. In this paper, an example of the use of hydrogeological-geochemical multidisciplinary approach in a plain area is showed. The study area is represented by the coastal plain between Versilia (to the northwestern) and Pisa plain (to the southestearn), involved in seawater intrusion. The multilayered aquifer system of the Versiliese-Pisan coastal plain is mainly made up of sandy and gravelly horizons. The aquifers are locally affected by intense exploiting for drinking, industrial and irrigation uses, inducing seawater intrusion. In order to estimate the seawater rate and to understand the mixing mechanism with freshwater, a project co-financed by the Migliarino S. Rossore Massaciuccoli Regional Park is being carried out since 2005. This project consists of a multidisciplinary study carried out by means of hydrostratigraphic correlations, water level measurements and physico-chemical (electric conductivity, temperature, pH), chemical (principal chemical elements and Br) and isotopic analysis (18O/16O and 2H/1H ratios). In this paper the main results regarding the zones between Viareggio and Torre del Lago and between Marina di Pisa and Livorno are presented. In the first area the 30 m thick unconfined sandy aquifer was studied, whereas in the second one the confined gravelly aquifer (10 m thick, on average) located at a depth between 50 and 100 m below the sea level was analyzed. In both zones, water levels below the sea level are referable to groundwater exploitation principally due to tourism companies and farms. Chemical and isotopic analysis in different periods highlighted a maximum salt water percentage variable in the intervals 15-30% (unconfined aquifer between Viareggio and Torre del Lago) and 7-9% (confined aquifer between Marina di Pisa and Livorno). Isotopic tools, together with conservative chemical parameters, allowed at understanding the seawater-freshwater mixing mechanisms and at verifying the preferential path of the seawater.
Approccio multidisciplinare idrogeologico, geochimico e isotopico nello studio dell’intrusione marina
GIANNECCHINI, ROBERTO;DOVERI M.
2014-01-01
Abstract
Since many years, the seawater intrusion is involving wide areas of the Italian coastal plains. The knowledge of this phenomenon is basic in managing and protection of the water resource. In this paper, an example of the use of hydrogeological-geochemical multidisciplinary approach in a plain area is showed. The study area is represented by the coastal plain between Versilia (to the northwestern) and Pisa plain (to the southestearn), involved in seawater intrusion. The multilayered aquifer system of the Versiliese-Pisan coastal plain is mainly made up of sandy and gravelly horizons. The aquifers are locally affected by intense exploiting for drinking, industrial and irrigation uses, inducing seawater intrusion. In order to estimate the seawater rate and to understand the mixing mechanism with freshwater, a project co-financed by the Migliarino S. Rossore Massaciuccoli Regional Park is being carried out since 2005. This project consists of a multidisciplinary study carried out by means of hydrostratigraphic correlations, water level measurements and physico-chemical (electric conductivity, temperature, pH), chemical (principal chemical elements and Br) and isotopic analysis (18O/16O and 2H/1H ratios). In this paper the main results regarding the zones between Viareggio and Torre del Lago and between Marina di Pisa and Livorno are presented. In the first area the 30 m thick unconfined sandy aquifer was studied, whereas in the second one the confined gravelly aquifer (10 m thick, on average) located at a depth between 50 and 100 m below the sea level was analyzed. In both zones, water levels below the sea level are referable to groundwater exploitation principally due to tourism companies and farms. Chemical and isotopic analysis in different periods highlighted a maximum salt water percentage variable in the intervals 15-30% (unconfined aquifer between Viareggio and Torre del Lago) and 7-9% (confined aquifer between Marina di Pisa and Livorno). Isotopic tools, together with conservative chemical parameters, allowed at understanding the seawater-freshwater mixing mechanisms and at verifying the preferential path of the seawater.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
