Venice uplift by seawater injection in a randomly heterogeneous aquifer
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 the Venice Lagoon might induce a land uplift of a few tens of centimeters over 10 years
with a very 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 communication
investigates the influence of a seawater injection in a randomly heterogeneous aquifer with particular
reference to the differential vertical displacements predicted at the ground surface. A Monte Carlo
simulation is carried out assuming a log-normal stationary process of the hydraulic conductivity,
namely the most important and naturally variable parameter, with a sensitivity analysis performed
on the variance σ2 of the associated random field. The
results indicate that gradients larger than those currently experienced in Venice at the building
and monument scale are never attained irrespective of σ2
and despite the possible highly uneven expansion of the injected formation because of the smoothing
effect exerted by the 600-m thick overburden.
