Through the extremely well-informed Fellows Mafia, I learned about the annual two week Environmental Film Fest in DC. There appear to be six or eight different movies shown each night in different venues across the city, with no venue being used more than once. I could easily identify several films each day that looked interesting, although I confess that my preferences have been somewhat influenced in favor of films shown at embassies. My niece came to visit for part of her spring break this past week, and she was game to join me for my first ever embassy visit.
The Italian Embassy wasn’t quite what either my niece or I expected. I think we were both anticipating an opulent mansion, but what we actually found was an enormous modern building instead. I can imagine that the many activities and missions of an active embassy could rapidly outgrow a more historic structure, and I can see the wisdom in having a building for the actual work of an embassy. After passing through security, we walked into a large open central space that would be ideal for receptions, and then the movie was in a room off to one side. There was still a generous helping of Italian Renaissance art on the walls, so it was not completely devoid of the expected Italian flavor.
The film we saw was called, “The Challenge of Venice,” and it focused on the difficulties being caused by rising sea levels due to climate change. I had always understood that Venice had canals, but I never gave much thought to why they existed other than being an interesting bit of architecture. From the splendid footage from the film, I can now envision that Venice is built on a collection of islands in a large lagoon, so water transport is really the most practical way of moving people and goods. The Grand Canal, which is the most famous of the waterways, carves a large backward S through the main island.
There are four inlets from the Adriatic Sea into the lagoon which allow tides to go in and out. The “acqua alta,” or high water, is usually a wintertime phenomenon that is the combination of several different factors. In addition to the astronomical tides caused by the phases of the moon, there is the seiche, which is an additional wave of tide that sweeps up and down the Adriatic. Winter also is often accompanied by the scirocco, a strong wind from the south, which helps pile water up at the northern end of the Adriatic Sea, behind the boot of Italy. Venice sits at the very top end of the boot. Unusually high tides occur when at least two out of the three, astronomical tides, seiche, and scirocco coincide. On a long term basis, two additional factors are expected to exacerbate the problem. First, the land in the area is also gradually subsiding, or sinking into the sea, so tides don’t have to be as high to be problematic. Second is the eustasy, the higher sea levels caused by climate change.
The first challenge of higher sea levels is an immediate disruption of foot and boat traffic. I didn’t immediately think that deliveries made by boat should be a problem, but those boats have to pass underneath the bridges, so if the water is too high, there isn’t enough clearance under the bridges and transport comes to a halt. It appeared that no resident or tourist in Venice should be without a sturdy pair of rain boots either. I saw the boots and thought, “Wellies!” and then followed up the thought with, “No, that’s a British term.” When the narrator went on to identify the boots as “Wellingtons,” I considered the man’s English accent and realized I had been right after all. Sometimes even Wellies aren’t enough to deal with the high water, so temporary elevated walkways are constructed to cross the immersed sidewalks. Hardy locals will don their special acqua alta boots, which look like waders to me, and some of the tourists will take off their shoes and roll up their pants, but three to four hours of high tide is obviously a great inconvenience all around. The famous Piazza San Marco is one of the low spots on the central island, so it floods frequently. I smiled at the pictures of the man standing in his front door using a long rod to retrieve the outdoor chairs and tables from the water in front of his restaurant.
On a longer term basis, the higher floods are causing problems for businesses, buildings, and homes. On the first floor of many structures, residents can identify the high water line from the exceptional tide in 1966 that flooded several feet up across the lagoon. The salt water also penetrates brick and stone, and when the water seeps out, the salt crystallizes. The development of the crystals creates and widens cracks, weakening the foundations and the walls. Individual buildings have been protected by chemical injections or by raising the buildings, but those solutions are not practical for the whole city or for the historic walkways.
That the Venetians have been coping with high water on a long term basis is evident in each person knowing exactly how many centimeters above sea level the floor of his building stands. I have certainly paid attention to elevations when I’m traveling in the mountains, but I have never had a similar awareness when I was close to the sea. Several of the locals who were interviewed as part of the documentary could explain that the floor of the shop was 100 cm high, and the water often rose 10 cm above that causing disruption or damage. The bakers seemed to take it in stride, but the man who made ornate costumes and masks was more negatively affected. When tides of 110 cm are expected, there are warning sirens and people receive text messages on their phones. The acqua alta is usually 120 cm or higher, and the record was over 160 cm.
Back in 2003, Italy felt that dealing with the rising seas threatening Venice was a national problem, and after considering a number of different possibilities, they settled on a huge engineering project to create floodgates that rise from the seabed to close off the inlets to the lagoon under unusually high tides. Called the MOSE project, the acronym is also intended to invoke Moses, who successfully held back the water of the Red Sea. MOSE is due to be completed in 2014, and combined with a complementary project to restore the wetlands in the lagoon and strengthen the coastline to help with water management, the hope is that people, the culture, and the history of Venice will then be protected during the increasing acqua altas.
Overall, it was an excellent film, and I learned both about Venice and about the special challenges of water in that city. I’m happy to recommend it, and I’m hoping to continue celebrating the environmental film fest this coming week.