Venice was on red alert for more floods and fierce winds on Saturday after an exceptionally high tide swamped the city of canals, where authorities have declared a state of emergency.Mayor Luigi Brugnaro ordered the iconic St Mark's Square closed on Friday as the latest sea surge struck with strong storms and winds battering the region.The square was open again on Saturday, but the city forecast a high water of 160cm for Sunday, lower than Tuesday's high of 187cm but still dangerous.Civil protection authorities issued a weather "red alert" for the Venice region, warning of violent winds which can whip up the sea, although Saturday's midday high was forecast to be a manageable 105 centimetres.Churches, shops and homes in the city, a UNESCO World Heritage site, have been inundated by unusually intense "acqua alta", or high water, which on Tuesday hit their highest level in half a century."We've destroyed Venice, we're talking about one billion (euros) in damage and that's just from the other day, not today," Brugnaro said.The crisis has prompted the government to release $22m in funds to tackle the devastation.Surveying the damage, Culture Minister Dario Franceschini warned the task of repairing the city would be huge. More than 50 churches had suffered damage, he said. Hotel reservations cancelledPrime Minister Giuseppe Conte declared a state of emergency for the city on Thursday.Residents whose houses have been hit are eligible for up to 5 000 euros in immediate government aid, while restaurant and shop owners can receive up to 20 000 euros and apply for more later.Mayor Brugnaro on Friday also announced the opening of a fund where people in Italy and around the world could contribute to the historic city's repair.One tourist, Italian Nicole Righetti, said she would be willing to pitch in. "It would be a shame to no longer be able to see these places, and I think everyone should give," Righetti said.Most of the city's cash machines were no longer working because of the water, making life even more difficult for tourists and Venetians.Despite being used to the inconvenience of their city's rising waters, some inhabitants expressed frustration."All the stock in the basement is lost," lamented Luciano, a worker at a shop along St. Mark's Square.He said he remembered well the infamous "acqua alta" of 1966, when the water rose to a level of 1.9m, the highest-ever since records began in 1923."These so frequent high waters have never happened before... this time there's so much more damage than in the past," he said.Hotels reported cancelled reservations, some as far ahead as December, following the widespread diffusion of images of Venice underwater.Tuesday's high waters submerged around 80% of the city, officials said.Many, including Venice's mayor, have blamed the disaster on global warming and warned that the country prone to natural disasters must wake up to the risks posed by ever more volatile seasons.The Serenissima, as the floating city is called, is home to 50 000 residents but receives 36 million global visitors each year.A massive infrastructure project called MOSE has been under way since 2003 to protect the city, but it has been plagued by cost overruns, corruption scandals and delays.