project to build seventy-nine enormous hinged gates that can separate
Venice and its lagoon from the Adriatic in times of flooding. The hol-
low steel gates, each of which measures about 65 feet to a side, will lie
flat on the seafloor at the three entrances to the lagoon. When an acqua
alta(literally, “high water”) occurs, the gates will swing up to form a
temporary wall, stopping the rising sea from entering the lagoon and
the city’s streets and squares. The gates would protect against flood
surges of up to 6 feet in height, sufficient protection to keep pace with
sea-level rise for at least 70 years, according to Giovanni Cecconi, an
engineer with the New Venice Consortium, an alliance of major Italian
engineering firms charged with designing, building, and operating the
massive project. “It’s not the final solution, it’s just a way to protect the
city during this century until another solution can come into place,” he
says.
Italian authorities have also started dredging canals, raising city
pavements, and repairing damaged seawalls, slowly making up for a
half-century of neglected maintenance. Italy expects to spend about
$40 million a year for the next decade on such projects in an effort to
buy the city some extra breathing room. “If you wish to defend the city
from flooding, first of all you must maintain what is already there,”
says Paolo Gardin, who oversees much of the work. So far, construction
crews have raised and restored many miles of canal walls and pave-
ments. On the satellite island of Burano, home to some of Venice’s
famous lace makers, Insula built a series of small floodgates at all the
island’s canal entrances, allowing it to cut itself off from the lagoon in
times of flooding. The only problem: the mini-gates provide protection
only for floods up to 4 1/2 feet above normal water levels. The 1966
flood—and floods in a globally warmed future—stood more than 6 feet
above normal water.
Thus exists the need for the big gates, say proponents of the mas-
sive project. “Virtually everyone agrees that the only ultimate solution
is to separate the lagoon from the Adriatic,” says Rafael L. Bras of the
Massachusetts Institute of Technology, who led an engineering team
that audited Venice’s gates project. “Italy should do what the Dutch
learned to do a long time ago: act now and think preventively,” Bras
says, rather than continuing to “take a wait and see attitude.”
Europe 35