Combined continuous electrical tomography
and very high resolution seismic surveys
to assess continental and marine groundwater mixing
L. Tosi, M. Bonardi, G. Brancolini, J. Frankenfield, F. Rizzetto
Institute of Marine Sciences, CNR, Venezia, Italy
L. Baradello, M. Zecchin, D. Nieto
National Institute of Oceanography and Experimental Geophysics, Trieste, Italy
P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
P. Shi, C. Tang, Q. Chen, D. Liu, Y. Sheng, Y. Xiao, D. Zhou
Yantai Institute of Coastal Zone Research, Yantai, China
F. Li
Department of Water Resources and Environment, Jinan, China
B. Chiozzotto, M. Giada
MORGAN Rilievi, Marghera-Venice, Italy
ABSTRACT
Salt contamination in the coastlands surrounding Venice Lagoon (Italy) and Laizhou
Bay (Shandong Province, China) is generally the result of the complex relationship
between fresh, continental groundwaters, paleo-saltwaters in deep aquifers, marine
waters, and the seawater encroachment upstream from the river mouths. Saltwater
intrusion is also enhanced by the presence of ancient, sandy, buried paleo-channels
that act as preferential pathways for groundwater flow and solute transport. The
characterization of these hydro-geo-morphological features, considering both the
architecture and the pore water quality, is an issue of paramount importance. In this
work, after a short overview of the saltwater contamination occurrence that affects the
coastlands of Venice Lagoon and Laizhou Bay, we report on the preliminary results of
a Very High Resolution Seismic and Continuous Electrical Tomography test carried
out in very shallow water (about 1 m) in the Venice Lagoon to test a technique suitable
for the better understanding of the surficial-groundwater mixing process. The
combined analysis of the two data sets highlights a correlation between
lithostratigraphic discontinuities and heterogeneity in the fluid filling the subsurface.
The promising results obtained in the Italian site support a prompt use of this
integrated methodology on the Chinese study area too.
