The warning siren howls in the dark.
As always, the flood arrives on the tide.
Water slops over the rim of the city’s canals, bubbles up through drains and, as the morning hours progress, surges into the ground-floor vestibules of palaces along the Grand Canal. It leaves stripes on sills, green and brown with a sticky scum of sewage.
The wind-driven high water — acqua alta — is a staple of Venetian life, like an espresso and a croissant con marmellata at a stand-up coffee bar.
Porters in knee-high waders set out elevated walkways. Shopkeepers slide cofferdams across doorways. Gondoliers duck their heads as they pass under bridges arched over swollen canals.
Brackish high tides swamp the city about 100 days a year — twice as often as 50 years ago. After a thousand years of adaptation to the water, Venice is foundering.
“There are no longer any homes at ground floor,” says Jane Da Mosto, who lives with her family near the Grand Canal. “Nobody risks being drowned in their sleep.”
Set at sea level in a shallow lagoon, Venice was designed by its founders to harmonize with the water, from the millions of alder pilings that anchor its grand palazzi in the muck to the maze of 177 canals that serve as streets and sewers.
By this year, the crypt of Mark the Evangelist in the city’s Basilica of St. Mark rested 8 inches below sea level, nearly 6 feet lower than when it was built in 828. Water seeps into the atrium virtually every day in winter, and the vestibule is often ankle-deep. At least seven times a year, much of the city is swamped.
When the cold bora wind blows from the northeast or the sirocco sweeps up from Africa, they drive waves across the narrow Adriatic into the Venice lagoon like stampeding cattle. The winds push an incoming tide swollen by millions of extra gallons, just as Katrina’s storm waters surged across Lake Pontchartrain into New Orleans.
On days when those winds are especially strong, they can pile tide upon tide, as occurred on Nov. 3, 1966, when a storm surge driven by 60-m.p.h. winds left Venice deep in a turbid stew of floating furniture and drowned rats.
`Like an alarm bell’
In that single disastrous surge, decades of municipal neglect and thoughtless industrial development surfaced.
“The flood was like an alarm bell about a process of decay,” says Da Mosto, co-author of “The Science of Saving Venice.”
As they have done for so many centuries, engineers set out to save this city of water one inch at a time.
Along the quay of Piazza San Marco, where 14 million tourists walk every year, two workmen heave up an 80-pound paving stone, dust it with a whisk broom and wrap it in plastic.
They number it and set it gently aside on a wooden pallet.
Each stone is unique, beveled by hand 150 years ago to fit the slope of the 18th Century pavement it overlaid. Fifteen inches below that is the red brick plaza of the 15th Century. Four feet below that is the walkway of the 13th Century.
Following a surveyor’s chalk line, the two masons smooth a thick layer of lime and sand and then tap the old paving stone back into place on top of it with an orange rubber mallet.
One antique paver at a time, the workmen raise the canal edge by 7 inches, to protect the world-famous plaza with an imperceptible ridge along the water line. At $2,000 a square yard, it is more like art restoration than urban renewal.
4th raising in 500 years
The $5 million project marks the fourth time in 500 years that city engineers have raised the city’s center to keep it dry.
From the 5th to the 11th Centuries, Venetians raised the level of the city by 6 feet, archeologists believe. The sea level today may be as much as 16 feet higher than when the lagoon originally formed about 6,000 years ago.
Since 2001, water authority engineers have spent almost $3 billion to refurbish the city’s sea walls, jetties and shorelines.
To restore 18 miles of protective barrier beaches, they spread 13 million cubic yards of sand, matching the shoreline’s precise shade of golden brown with the skill of a tailor reweaving an expensive suit. They anchored new dunes with a million plugs of grass and tamarisk.
But it is no longer enough to keep Venice level with the sea.
The specter of higher seas has forced the city to adopt more drastic measures.
Anything that might block the lagoon, however, must accommodate a port that handles almost one-third the harbor traffic of New York, a busy fishing fleet and the largest cruise ship terminal in the Mediterranean — without spoiling architecture, ruining vistas, affecting water quality or disrupting Italy’s largest wetlands.
“Everybody was pushing us to solve the flood problem by doing nothing,” says Alberto Scotti, 59, president of Technital, an engineering firm that specializes in coastal works.
But Scotti and his colleagues had a daring idea. They conceived a $4.5 billion dam that no one would see.
The ingenious design calls for 78 massive mobile gates to be installed across the three inlets that connect Venice to the sea. They would be hinged on the sea floor like trap doors. Under normal circumstances, the gates would remain out of sight and out of the way, parked unobtrusively on the sea bottom, the consortium’s engineers say.
But when the tide rises high enough, the gates would be pumped full of air and lifted up to block any threatening storm surge. They are designed to bob freely on the current, barely visible above the waves.
Based on worst-case projections of sea level rise, the gates eventually could be closed between seven and 39 times a year.
Critics worry that the barrier will destroy the city it is meant to save by turning the lagoon into a stagnant cesspool. Opponents argue that a systematic restoration of the lagoon would better solve the most serious flooding problems.
Like New Orleans, Venice can no longer afford its own renewal. Almost bankrupt, the city plans to auction a dozen of its most historic Renaissance buildings and palaces next month, to raise cash for operating expenses.
As planners in Venice ponder the future, a broader question haunts them. For whom will the city be saved — for the millions of tourists who visit every year or for the 60,000 residents who call it home?
Caught between high tide and the high cost of living, the population of Venice has fallen faster than that of any other West European city. If its problems cannot be solved, Venice will become Italy’s New Orleans, government officials warn.
