The Venice Tide Barrier System - MOSE Project

Introduction:

The city Venice located on the east coast of Italy, is a world-famous tourist spot. It was hit by several floods and massive waves from the Adriatic Sea in the past few decades. Many experts claim that the water level in the sea is rising day by day. In 1966, it became a significant concern as the tides rose to an enormous height of more than 7 feet above the seawater level. This project consists of 78 gigantic steel panels across the three inlets that allow water to surge from the Adriatic Sea into the Venice lagoon.

The MOSE System:

The Venice city lagoon has three main water inlets at Malamocco, Chioggia, and Lido. To protect the city from flooding, the government planned to temporarily close these three water inlets. In 2003, the approval for MOSE, an Italian acronym for Experimental Electromechanical Module, was passed to construct an artificial barrier that would protect the city from any future floods. Its fundamental idea was to engage a series of oscillating inflatable flood gates strategically positioned at the bed floor of the inlets of the three main water lagoons. The platform on which the inflatable flood gates will rest would also support towers that accommodate the control system of the gates.

How does it work?

When the metrological department forecasts the emergence of high tides in the Adriatic Ocean, the control system activates the MOSE. The project's main elements are the 78 enormous underwater gates placed between the Adriatic Sea and the Venetian lagoon. The flood gates at normal condition lie below the water level, completely submerged. When the tides appear, the control system fills compressed air into the inflatable gates. Due to the principle of buoyancy, the flood gates would come above the water and block the flow of the incoming wave.

Construction process:

Each gate is around 92 feet long, 65 feet in width and up to 16 feet thick. The heaviest of these gates weighs about 350 tons, and that is as much as a Boeing 747 airliner. They are supported by around 125 feet long steel and concrete pilings that measure about 500mm in diameter and 20m in length. Flood gates are hallowed at the bottom to allow the inflow of compressed air. The hinges form the technological heart of the sea defence system. There are 156 hinges, two for each gate and several reserve elements. They constrain the gates to the housing structures, allow them to move and connect the gates to the operating plant. After the tidal threat is neutralized, the compressed air is pumped out, and water is pumped in. As a result of which those flood gates will again sink to the bottom of the sea bed. 

         

WRITTEN BY : Satyajeet Swain