On October 3, 2020, the long-awaited initial operation of the gigantic Mose flood protection system (Modulo Sperimentale Elettromeccanico), which is supposed to protect Venice from major flooding in the future. Although the premiere was a success, the unique and, above all, gigantic construction has also attracted criticism. Can this ambitious project really protect the UNESCO World Heritage Site from further flooding?
Technical masterpiece with limitations
On November 12, 2019, a flood of 187 cm above mean sea level flooded eighty percent of Venice’s old town. The second-highest “Acqua alta” of all time destroyed or damaged numerous cultural monuments, museums and valuable archives. A state of emergency had to be declared. This scenario should never have happened, because the MOSE flood protection system should have been completed and in operation long before. But corruption, construction freezes and cutbacks prevented the system from being put into operation as planned after the groundbreaking ceremony held by then Prime Minister Silvio Berlusconi on March 14, 2003. As a result, the suffering population had to be repeatedly put off. With a delay of more than five years, Mose finally started on October 3, 2020.
78 yellow steel giants form an imposing protective barrier
From a technical point of view, Mose is an incredible project : 78 steel elements, each weighing 250 tons, are positioned in the lagoon access points Bocca di Lido, Bocca di Malamocco and Bocca di Chioggia, and can protect Venice from flooding within about 30 minutes. The barriers are activated at a height of 130 cm above mean sea level and provide protection at a level of up to three meters above mean sea level.
Similar to a ship’s dock, the barrier is raised as follows: the flaps in large steel boxes are flooded on the seabed and when closed, compressed air is used to push the water out. The gates, which are five meters thick and 600 m² in size, are raised out of the sea. To ensure the continued flow of shipping traffic, there is a lock at Malamocco. Ships up to 280 meters long and with a draft of up to 12 meters can pass through there.
High costs and fears for the future
Despite the successful first use in October 2020 and two further uses in the same month, when the inhabitants of Venice did not get wet feet thanks to Mose, critical voices are increasing. On December 8, 2020, despite an approaching storm, Mose was not deployed because a level of just under 130 cm was forecast. A devastating mistake: the strong sirocco wind caused the sea level to rise to 138 cm, followed by an avoidable flood of the lagoon city.
The municipality argued that the deterioration happened rapidly and that they were completely unprepared. Now, the modern flood barrier is facing growing criticism. In addition to the costs (activating Mose costs around €300,000), questions are also being raised about expensive maintenance work and environmental aspects.
Ultimately, there are concerns that Mose may have been designed too low after all. “Venice will be the first lagoon to only let water in when needed. But we have to start thinking beyond Mose now, because Venice is exposed to an accelerated rise in water levels due to climate change. What used to happen once a century is now happening every 25 years,” warns Giovanni Cecconi, a water expert at Ca Foscari University of Venice.
At present, Mose provides reliable protection at a level of three meters. It would also have no problem dealing with the historic flood of 1966, when the sea level rose to 194 cm. However, the recent storms and flooding have clearly shown that the ever-increasing climate change knows no limits.
