Venice's St Mark's Square was under water on Tuesday as strong winds and heavy rains pushed into the lagoon city after a newly installed system of mobile artificial dams failed to activate.

Local residents, long accustomed to perennial high water events or "acqua alta" in Italian, pulled on their rubber boots once more to deal with flooding that reached a high of 1.37 meters (4.5 feet) above sea level in the afternoon.

The waters drowned St Mark's Square, the Renaissance city's lowest area at about one meter above sea level, and invaded the famous basilica as many shopkeepers blocked their entrances with wood panels to keep the water out.

A massive flood defense system called MOSE aimed at protecting Venice's lagoon during high tide up to three meters was finally installed in October. The network of water-filled caissons is designed to be raised within 30 minutes to create a barrier capable of resisting a water rise of three meters above normal.

But on Tuesday, the system failed to swing into action because the forecast erroneously predicted a rise of only 1.2 meters (four feet) above sea level.

The system requires 48 hours' notice to be activated, according to the Straitstimes. Venice Mayor Luigi Brugnaro said that "to activate MOSE a bigger forecast is necessary." 

"We will have to review the rules of the command post."

Last November, the water reached a peak of 1.87 meters (six feet) above sea level, one of the highest ever recorded. Dozens of churches with UNESCO World Heritage status were damaged.

The MOSE infrastructure project, intended to protect the city of Venice, Italy, and the Venetian Lagoon from flooding, began in 2003 but was plagued by cost overruns, corruption scandals and delays. The project has cost about seven billion euros ($8 billion), versus an original estimate of two billion.

(With input from Reuters)