The role of aquifer heterogeneity in the anthropogenic uplift of Venice
M. Ferronato, G. Gambolati, P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
ABSTRACT
Recent numerical analyses indicate that injecting seawater into a 600-800 m
deep brackish aquifer underlying Venice might induce a land uplift of a few
tens of centimetres over 10 years, with a significant mitigation of the floods
that periodically plague the city. In real porous media, however, the hydraulic
conductivity of the injected formation may exhibit a strong heterogeneity which
could impact on the uniformity of the expected heave. The present paper
investigates the influence of such heterogeneity on the vertical displacements
predicted at the ground surface during seawater injection. A Monte Carlo
simulation is carried out assuming a log-normal stationary distribution for
the hydraulic conductivity with a sensitivity analysis performed on its
variance. The results indicate that differential displacements larger than
those currently experienced in Venice are never attained irrespective of the
possible, highly uneven aquifer expansion, because of the smoothing effect
exerted by the overburden.
