Published online 15 January 2004 | Nature | doi:10.1038/news040112-8

News

Saving Venice

Plans have been resurrected to raise Venice above the encroaching sea.

This story is from the news section of the journal Nature

Venice could be going up in the world - by 30 cm in 10 years.Venice could be going up in the world - by 30 cm in 10 years.© alamy.com

Venice could be saved from sinking into the sea by using oil-industry technology to pump fluid underneath the city, says a team of geomechanical engineers.

Led by Giuseppe Gambolati of the University of Padua, the group published its proposal in a paper last month1. The idea revisits a proposal first mooted in the 1970s, but Gambolati's team claims that advances in technology would now allow Venice to be raised safely.

The proposal will next be considered by CORILA, the consortium charged with coordinating research into the city's lagoon system.

Venice floods regularly, owing to climate-induced increases in sea levels in the lagoon and to over-extraction of groundwater, which has led to subsidence.

The Consorzio Venezia Nuova, the public authority responsible for protecting Venice, has taken various steps. These include raising the pavement in very low-lying areas, and building a controversial, huge mobile flood barrier called MOSE, whose gates will close during extreme sea surges. MOSE, costed at E3 billion (US$3.8 billion), is due to come into operation in 2011 - but rising sea levels could render it ineffective well within 100 years.

Gambolati says that his plan could lift Venice by up to 30 cm in 10 years, "which would help to counter the effect of rising sea levels and extend MOSE's useful life".

His proposal involves injecting either carbon dioxide from local power stations or - more simply and cheaply - sea water, into a sandy layer 600-800 metres below the lagoon. The layer is sandwiched between clay below and 25 metres of relatively impermeable cap rock above.

Pierpaolo Campostrini, director of CORILA, says of the earlier proposals to pump fluid below Venice: "The ideas then involved pumping only 40 or 50 metres below the surface, which would have led to uneven raising."

Gambolati says that slow pumping over a period of 10 years at greater depth should allow lifting to be even. Sceptics, such as Rafael Bras, a hydrologist from the Massachusetts Institute of Technology, warn that much more information is needed to establish the idea's feasibility.

CORILA now plans a feasibility study, including geological and geophysical analyses of the sea bed in the lagoon and a test drilling site a safe distance away. 

  • References

    1. Comerlati, A. et al. Eos, 84, 552 - 553, (2003). | Article |