Saltwater contamination in the managed low-lying farmland of the
Venice coast, Italy: An assessment of vulnerability
C. Da Lio, L. Tosi
Institute of Marine Sciences, CNR, Venezia, Italy
E. Carol, E. Kruse
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cátedra de Hidrología General, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata,Argentina
P. Teatini
Dept. of Civil, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
The original morphology and hydrogeology of many low-lying coastlands worldwide have been significantly
modified over the last century through river diversion, embankment built-up, and large-scale land reclamation
projects. This led to a progressive shifting of the groundwater-surficial water exchanges from naturally to
anthropogenically driven. In this human-influenced hydrologic landscape, the saltwater contamination usually
jeopardizes the soil productivity. In the coastland south of Venice (Italy), several well log measurements,
chemical and isotope analyses have been performed over the last decade to characterize the occurrence of the
salt contamination. The processing of this huge dataset highlights a permanent variously-shaped saline contamination
up to 20 km inland, with different conditions in relation with the various geomorphological features of
the area. The results point out the important role of the land reclamation in shaping the present-day salt contamination
and reveal the contribution of precipitation, river discharge, lagoon and seawater to the shallow groundwater
in the various coastal sectors. Moreover, an original vulnerability map to salt contamination in relation to
the farmland productivity has been developed taking into account the electrical conductivity of the upper aquifer
in the worst condition, the ground elevation, and the distance from salt and fresh surface water sources. Finally,
the study allows highlighting the limit of traditional investigations in monitoring saltwater contamination at the
regional scale in managed Holocene coastal environments. Possible improvements are outlined.
