Venice is built on a group of small islands and is surrounded by water, with the Adriatic Sea to the east and the Venetian Lagoon to the west. The city is also built on soft, marshy ground, which makes it prone to flooding.
One of the main reasons why Venice is always flooding is due to a phenomenon called acqua alta, which is caused by a combination of factors. Acqua alta occurs when high tides, strong winds, and low atmospheric pressure converge, causing water levels to rise and flood the city. The high tides are a result of the gravitational pull of the moon and the sun, and they are more pronounced during the spring and fall equinoxes. The strong winds, such as the sirocco from the south or the bora from the north, can push water from the Adriatic Sea into the Venetian Lagoon and cause it to overflow. The low atmospheric pressure can also cause the sea level to rise.
In addition to acqua alta, there are other factors that contribute to the flooding of Venice. The city is sinking at a rate of about 1-2 millimeters per year, which means that the relative sea level is rising. This is due to subsidence, which is the gradual sinking of the land due to natural and human causes such as groundwater extraction and the weight of buildings. Climate change is also contributing to the flooding of Venice, as rising temperatures are causing the polar ice caps to melt and the sea level to rise.
Overall, the combination of acqua alta, sinking land, and rising sea levels due to climate change make Venice particularly vulnerable to flooding. The city has implemented a variety of measures to try to mitigate the effects of flooding, such as mobile flood barriers and a system of canals and pumps, but it remains a significant challenge to protect the city from the increasing frequency and severity of flooding events.