Generally Venice only has high water in
Autumn and Winter and even then it is not every day that
the streets are flooded. However when a higher than usual
tide is expected in the city, sirens blare to warn the
population so that they can prepar themselves. Maps as
posted at the boat stops showing alternative pedestian
routes around the city that are equipped with special
footbridges to avoid the high water and to reach the main
parts of Venice.
For further information call the Venetian Tides Service.