Saltwater contamination in the lowlying coastland of the Venice Lagoon, Italy

Abstract

TIle southem portion ofthe Venice coastland includes a very precarious environment. Due to an elevation down to 4 m below msl, ilie Venice Lagoon atld Adriatic Sea proximity, and the encroachment of seawater from ilie mouth of the river network up to 20 km inland, salt contamination of land atld groundwater is a severe problem that is seriously affecting the farmland productivity. An interdisciplinary multi-scale research is ongoing with the aim of understanding ilie contamination process, quantifying the effect of ilie saltwater intrusion of the crop production, and proposing possible mitigation strategies. A 21-ha representative basin has been selected and deeply monitored from the hydrogeological atld agricultural points of view. It has been clearly outlined that in the upper 5 to 10 m mainly the lowpermeable soils are contaminated by salt. Conversely, fresh to brackish waters are located in the sandy elongated paleo-channels. This is likely due to the origin of the area which was a salty marshlatld since one century ago. The freshwater supplied for almost 100 years by the rainfall and leakage from the river and chatlnel beds has been able to reduce ilie salt concentration only in the highly permeable deposits.