Caratterizzazione geochimica dell’acquifero alluvionale della piana di Licata (AG)

The preliminary results concerning the hydrodynamic and geochemical conditions of the underground water resources of the region surrounding Licata (Agrigento province, Sicily) are presented. The research was focused on the unconfined aquifer (or locally semiconfined) developed in the Quaternari deposits of the Licata plain. The evolution of the Salso river and the coastal dynamics, characterised by transgresions and coast-line retreats, qualitatively and quantitatively influenced the underground water resources. In this complex geological contest, also the anthropogenic activities played a crucial role, especially the farming activity as largely testified by the occurrence of numerous greenhouses that cover most of the plain. The analysis of thermopluviometric data concernine the last 75 year allowed to obtain inferences on the climatic evolution of this region characterised by a mean annual temperature of about 18 °C of mean annual precipitations of only 454 mm. The principal feeding of the aquifer is due to infiltration from precipitations and lateral outflow from the Salso river. The high salinity of the river especially during Summer periods and the intense farming activities played a crucial role for the quality of the aquifer.