Venice versus The Sea

Venice versus The Sea

The Venitians put down roots-on a cluster of islands in a lagoon at the north end of the Adriatic Sea-by driving alder and oak piles into the sandy ground. atop these foundations they built homes and palaces and began a battle against the ceaseless rise and fall of the tides. The city's structure, despite reinforcements, have suffered the assault of brackish water, sea-level rise, and subsidence (sinking)-some five inches in the past century. Excessive pumping of groundwater contributed to subsidence.

MOSE : TO STEM THE TIDES

The MOSE (acryonim for Modulo Sperimentale Elettromeccanico, in english Experimental Electromechanical Module) project, begun in 2003 and projected to be complete in 2014, will string four barriers made up of 78 floodgates-at a cost of nearly six billion dollars-across the three inlets (left) to Venice's lagoon. The gates, raised when unusually high tides threaten flooding, will block seawater from pouring into the lagoon. Controversial from the start, the project provoked years of political wrangling as well as worries about lagoon ecology.

How it works

1. Hollow steel gates filled with water lie flat in housing caissons built into the lagoon bed at each inlet.
2. When a flood is predicted, air is pumped into the gates to displace water and make them bouyant, allowing them to rise within a half hour.
3. Fully elevated, the gates separate sea from lagoon. When the tide recedes, water flows back into the gates to lower them.