Venice is not just a stage set. It is also a city with a resident population, which has productive activities, transportation and services. But how does the “Venice system” work? How do the tides in the lagoon behave? How are the canals formed? And the embankments? What’s under the buildings? Venice Backstage, a project conceived by Insula spa, the operative arm of the City for urban maintenance, is about what happens behind the curtains, to make the fragile beauty of this fantastic city easier to appreciate.
Layout - The city of Venice, Italy is not built on solid ground, but rather a cluster of mud islands in a lagoon on the Adriatic sea. The mud islands are divided by the Grand Canal, which is, by definition, more a river than a canal. The city is built upon pilings driven 15 feet into the clay below. Twenty-five miles of canals act as tributaries between the islands, all draining to the Grand Canal, which flows into the Adriatic.
Purpose - The primary purpose of the canal system is drainage, to avoid flooding in the city. High barometric pressure on the lower Adriatic, combined with northward blowing winds, frequently push up the water level on the northern end of the sea. The canal system keeps the city from being inundated with water, though floods are still common.
Navigation - A by-product of the canal system in Venice is navigation. The canals are like streets and the gondolas are like taxis. Gondoliers use long wooden poles to guide their craft through the city's canals. The deepest point of the canal system is fifteen feet in the Grand Canal. Most canals are between five and ten feet deep, making it easy for the gondoliers to use the poles, rather than paddles or rudders, to stick into the earth at the bottom of the canal and steer the vessel.
Result - Despite the drainage of the canal system Venice still floods frequently. The canals and city squares are marked with high wooden and metal poles that measure the water level. When the water reaches a certain level a flood alarm sounds. The highest level ever reached was during the floods of 1966. Since then the population of Venice has decreased annually. Venice is a dying city propped up not only by those pilings that keep it from sinking but also the tourist trade, which keeps the canals filled with gondolas.