Peatland oxidation enhances subsidence in the Venice watershed
G. Gambolati, M. Putti, P. Teatini
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
M. Camporese
Dept. Hydraulic, Maritime, Environmental and Geotechnical Engineering,
University of Padova, Padova, 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
F. Rizzetto, L. Tosi
Institute of Marine Sciences, National Research Council, Venezia, Italy
ABSTRACT
The southernmost part of the Venice Lagoon catchment was progressively reclaimed
starting from the end of the XIX century and finishing in the late thirties. As a
major result the area was turned into a fertile farmland at present kept dry by a
distributed drainage system that collects the water from a capillary network of
ditches and pumps it into the lagoon or the sea. By its very origin this area lies
below the sea level and progressively lowers mainly because of bio-oxidation of the
histosols that represent a large fraction of the outcropping soil in the area.
This process occurs in close connection with the agricultural practices and is
currently responsible of a subsidence rate between 1.5 and 2 cm/year.
To study the land settlement that plagues this area, the VOSS (Venice Organic Soil
Subsidence) project was undertaken with the objective to understand the process,
quantifying the past and present subsidence rate and advancing possible remedial
measures without penalizing the economy of the area. The study, conducted in close
collaboration with the Land Reclamation Authority (Consorzio di Bonifica) and the
farmland owners, is focused on a hydrologically controlled catchment, the Zennare
Basin.
