Monitoring and modeling peat soil subsidence in the Venice Lagoon
M. Camporese
Dept. Hydraulic, Maritime, Environmental, and Geotechnical Engineering,
University of Padova, Padova, Italy
G. Gambolati, M. Putti, P. Teatini,
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
M. Bonardi, F. Rizzetto, L. Tosi
Institute of Marine Sciences, National Research Council, Venezia, Italy
S. Ferraris
Dip. Economia e Ingegneria Agraria, Forestale e Ambientale,
University of Torino, Grugliasco (Torino), Italy
G. Gasparetto Stori
Consorzio Bonifica Adige-Bacchiglione, Padova, Italy
V. Nicoletti, S. Silvestri
Sistema Informativo, Venice Water Authority, Venezia, Italy
P. Salandin
Institute of Hydraulics and Road Infrastructures, Polytechnic University
of Marche, Ancona, Italy
ABSTRACT
The Venice Lagoon is characterized by a fast morphodynamics appreciable not only over
the geological scale but also in historical and modern times. The lagoon environment
proves very sensitive to even minor modifications of the natural and anthropogenic
controlling factors. An important human endeavor accomplished in the past century is the
reclamation of the southernmost lagoon area that has been turned into a fertile farmland.
The reclaimed soil is reach in organic matter (peat) that may oxidize with release of
carbon dioxide to the atmosphere. The continuous loss of carbon is causing a pronounced
settlement of the farmland that lies below the present sea/lagoon level. This enhances
the flood hazard and impacts noticeably on the maintenance and operational costs of the
drainage system. Total peatland subsidence is estimated at 1.5 m over the last 70 years
with a current rate of 1.5-2 cm/year. The geochemical reaction is primarily controlled
by soil water content and temperature, and is much influenced by agricultural practices,
crop rotation, and depth to the water table. A small (24 km2) controlled
catchment located in the area has been instrumented for accurately monitoring the basic
parameters and recording the ground motion. The in situ measurements have been integrated
with the combined use of remote sensing data to help cast light on the process and
identify the mitigation strategies.
