In 2019, without mobile barriers, the sequence of events was similar to this year. First, ostro and sirocco had blown from the south, and the rising tide had pushed against the houses of Venice; then, after having caused millions of damages, in a few minutes the wind had turned and in the night had vented its blind fury against the inhabited centers on the other side of the lagoon, such as Pellestrina.
What is Moses
The Mose is a colossal system of four retractable dams, a work of engineering unique in the world, designed starting in the 1980s. It is made up of 78 mobile sluice gates that rest on the bottom of the three inlets, the arms of the sea that join the Adriatic with the lagoon. When the water exceeds the safety level, the sluice gates rise side by side until they close the entrance to the sea inside the lagoon.
The first stone was laid on May 14, 2003 by Silvio Berlusconi in favor of television cameras. After 19 years it’s almost over; it works but some fittings have to be completed. Total cost of the work, with the complete package, around 6 billion. Annual operating cost, including staff salaries, about 100 million. There were Pharaonic bribes and Babylonian dissipations; in 2014 an investigation had led to the arrest of 35 people: the cost of the malfeasance is still an incomplete figure, certainly many tens of millions.
How Moses works
The lagoon and the sea are joined by 3 inlets where the tide flows in and out with 12-hour cycles (6 hours decreasing and 6 hours increasing). When the tide is too intense, beyond 110 centimetres, mobile barriers rise from the bottom of the three inlets. One in Chioggia (fishing port), one in Malamocco (large oil tankers, ferries to the Levant, container ships and the now sporadic cruises) and two barriers in the large mouth of the Lido.
The lifting operations are carried out by emergency teams made up of around one hundred workers in shifts. In the control rooms there are mechanical engineers, physicists, computer engineers, on the plants the highly specialized technicians who start up valves, travel through the tunnels under the sea bed, activate the devices.