Why is Venice, the "Water City", suffering from a severe water shortage? Experts explain three reasons

Recently, the water level of the river in Venice, Italy, dropped significantly, and the riverbed dried up. Netizens couldn't help but sigh that the "water city" had dried up! Hu Xiao, chief analyst of China Weather Network, said that there are three reasons for the exposure of the dry riverbed in Venice, which is the result of the combined effects of marine activities, weather and climate change.

According to @CCTV.com, the water level in the ancient Italian city of Venice has dropped significantly recently, resulting in a rare water shortage. Inland rivers have dried up in many places, and the local main means of transportation, the "gondola", has run aground on the shore. The current average water level of Venice's inland rivers is -0.35 meters above sea level.

The "gondola" ran aground. (Photo source: People's Vision/Copyright photo source: Visual China)

Why is there drought in Venice, the "water city"? Hu Xiao, chief meteorological analyst at China Weather Network, said there are three reasons for the drought in Venice.

First of all, from the weather situation, since March, a huge warm high pressure has controlled the whole of Italy. Under the influence of high pressure, low water levels are prone to occur. Generally, one atmospheric pressure affects 1 cm of sea level. Continuous high pressure causes the atmospheric pressure on the sea level to increase, and the sea level water level drops accordingly.

European high-altitude pressure field map, the red circle is marked as a high-pressure control area. (Data source: European Center)

Second, the precipitation in Europe has been more in the east and less in the west since the beginning of this year. Italy, located in the south-central part of Europe, has received less precipitation. For Venice, February is the month with the least precipitation in the whole year, but this year it is even less. The local precipitation in February this year was only 3.4 mm, which is abnormally less than the 50 mm in February in normal years, which also led to insufficient river recharge.

Another most important factor is the tide. Venice is close to the sea (Adriatic Sea), and its water level is greatly affected by the tide. When the sea level rises, the water level is high, and when the sea level drops, the water level is low. This has been fully reflected in several droughts and floods, and only then did the Moses Plan (building a dam on the lagoon to block the tide) come into operation in 2018. Around the first and fifteenth day of the lunar calendar, the tidal activity is most obvious, and the tidal difference is also the largest at this time. From the two tidal timetables below, it can be seen that compared with February 28 (the sixteenth day of the lunar calendar) and February 19 (the eighth day of the lunar calendar), the tidal difference is obviously larger, and the water level during low tide is also lower. Without the supply of seawater, the "water city" will inevitably "cry out thirst".

In our impression, floods are the main threat to Venice, but in fact, droughts often plague this small city in winter. Hu Xiao introduced that today, coastal cities often face alternating droughts and floods, which is closely related to human activities, climate change, and changes in the marine environment. The theme of this year's World Meteorological Day is "Ocean, Our Climate and Weather". It is the responsibility of each of us to care about ocean changes, raise awareness of environmental protection and put it into practice.