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, which favours seawater intrusion. In order to study this phenomenon and 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 in 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 short paper the main results regarding the zones between Burlamacca Canal and Bufalina Ditch (zone A) and between Arno River and Scolmatore Canal (zone C) are presented. In the intermediate area (zone B) the study is still in progress. In the zone A the 30 m thick unconfined sandy aquifer was studied, whereas in the zone B the confined gravelly aquifer (10 20 m thick) 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% and 7 9% for A and C zones, respectively. Isotopic tools, together with conservative chemical parameters, allowed understanding of the seawater freshwater mixing mechanisms and to verify the preferential path of the seawater.
Seawater intrusion in the Versiliese-Pisan coastal aquifer system (North-western Tuscany): results from a hydrogeologic-hydrogeochemical study
DOVERI M;GIANNECCHINI, ROBERTO;
2010-01-01
Abstract
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, which favours seawater intrusion. In order to study this phenomenon and 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 in 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 short paper the main results regarding the zones between Burlamacca Canal and Bufalina Ditch (zone A) and between Arno River and Scolmatore Canal (zone C) are presented. In the intermediate area (zone B) the study is still in progress. In the zone A the 30 m thick unconfined sandy aquifer was studied, whereas in the zone B the confined gravelly aquifer (10 20 m thick) 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% and 7 9% for A and C zones, respectively. Isotopic tools, together with conservative chemical parameters, allowed understanding of the seawater freshwater mixing mechanisms and to verify the preferential path of the seawater.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
