National Geographic : 2009 Aug
N RIALTO BRIDGE GRAND CANAL Silt Sand, silt, and clay Sand Clay Clay Sand PALAZZO DEI CAMERLENGHI Stone Wood piles (Original structure, 16th century) Floor levels Original Raised Reinforced area GRAND CANAL 46 ft Lagoon bed Stone layer Lagoon of Venice Malamocco inlet Venice 7 MILES Lagoon of Venice Venice Malamocco inlet Lido inlet Chioggia inlet Adriatic Sea 7mi e Venetians 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. e city s structures, despite reinforcements, have su ered the assault of brackish water, sea-level rise, and subsidence (sinking)--- some ve inches in the past century. Excessive pumping of ground- water contributed to subsidence. The MOSE 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 MOSE: TO STEM THE TIDES Hollow steel gates filled with water lie flat in housing caissons built into the lagoon bed at each inlet. 1 FERNANDO G. BAPTISTA AND ALEJANDRO TUMAS, NG STAFF SOURCES: CITY OF VENICE; MINISTRY OF INFRASTRUCTURE AND TRANSPORT VENICE WATER AUTHORITY THROUGH ITS CONCESSIONARY CONSORZIO VENEZIA NUOVA; INSULA; YUIL EPRIM, CONSORZIO VENEZIA NUOVA VERSUS VENICE THE SEA DETAIL OF MALAMOCCO BARRIER Buildings and MOSE barriers drawn to scale. Tide-level scale rounded to nearest tenth.