The news about Venice sinking are all over the Internet. Everyone knew that Venice was going to sink someday, but what people didn’t realize was how quickly this is happening. That Venice still exists today is already a miracle, knowing that it is a city full of marble buildings which was built on an ancient wooden structure.
But, how true and how bad is this situation really?
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Threats to Venice
Something very important is the place and the terrain on wich Venice was build on.
The city was build on hundred low-lying salt marsh islands almost two thousand years ago. These salt marsh islands are slowly dissolving, and therefore the city slowly, but periodically sinks into the lagoon.
Apart from this Issue there are some other wich also affect Venices survival:
Boat traffic: Big boats run by a motor, produce waves. These waves erode the canal walls and the salt islands that remain.
“Acqua alta”
“Acqua alta”
This specific phenomenon consists of extremely high tides wich enter the lagoon, and end up flooding the canals and the city itself. This happens when the water level is 90mm above normal. The worst case of “aqua Alta” was the one wich produced the historic floodingof 1966 when the water level went up to 194 cm. To make it easier to understand this situation, when the water rises 90cm, St marks´s square already floods.
However, these floodings were something abnormal and sporadic. But nowadays it is safe to say that at least 60 days per year are characterized by high tides and several floodings.
This is Venices biggest threat.
The main cause behind the acqua alta is a more global concern:rising sea levels. Due to climate change, the periodicity of the aqua alta has been multiplied. Venice having floodings is nothing new, but the fact that the flooding are becoming more regular and more destructive is alarming.
Venice in the future
A question that is often asked is: How much is Venice actually sinking per year?, and according to research, the city sinks, on average, 1-2 millimeters per year!
Flood risk needs to be integrated into a city’s vision: how do we want our city to look like in 10, 20, 50 years?
Swenja Surminski
Head of adaptation research at the Grantham Research Institute on Climate Change and the Environment in London,
More or less, it consists of several sea-based defensive barriers made up of 78 mobile gates, each 20m wide and located at strategic locations to create a “coastal cordon” which, it is hoped, will minimize major flooding events. These barriers will remain submerged until the water level rises above 110cm. The problem is, that the construction began in 2003, and it still isn’t finished. The constructors announced that it should be ready by the end of 2023.
In addition, the Mose project will end up costing around €8bn. It is also not a long-term solution, it will maybe work for more or less 100 years, knowing that the constant opening and closing of the barriers will also eventually “doom” the lagoon. This will lead to the destruction of the lagoons ecosystem.
Therefore, taking into consideration all the data commented on the paragraph above, experts come to the following conclusion; a Dutch-style solution will have to be introduced. Moreover, this solution takes a very long time to build and is very expensive. The dam system is approximately 30km long, that is roughly 18 times the size of Mose.
Conclusion
In conclusion, we need to be seeking those ultimate solutions right now, before it is too late. In the end, Venice’s very position as such an admired and sought after city may be the key to making these protective changes happen here first.
I don´t think that the world will let Venice sink
Fabio Carrera
Professor at Worcester Polytechnic Institute in Massachusetts and founder of Venice Project Center
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When storms with strong winds roam northeasterly across Italy and Adriatic tides run high, engineers would activate a system that pumped compressed air into the gates. The air would force out the water, enabling the gates to rise on hinges and form a barrier against the surging seas.
In the last century, Venice has sunk by about nine inches. Meanwhile, the waters around Venice are rising, a phenomenon that's especially apparent in winter. The notorious acqua alta happens when an unusually high tide combines with strong sirocco winds and a storm.
The city's ground level is currently sinking by around 1mm a year due to natural processes. Human activities have in the past made this worse, particularly the practice of pumping groundwater from beneath the lagoon in the 20th century.
A UNESCO report says that along with over-tourism and construction, climate change-induced sea level rise and extreme weather have put Venice's storied old buildings and landscapes at risk. In November 2019, floods endangered historical treasures and buildings.
Many climate experts suggest that Venice could sink by 2100. With many projects going on around and in Venice, these could potentially slow the progression of the water infiltrating this Italian city.
Yet if the waters are not held at bay, there is little doubt that Venice will eventually be submerged and uninhabitable. Today, Venice is safe, but it is staring at a future of excruciating trade-offs, with the sea level so high so often that the city will require constant protection.
How long is this expected to last – and will it happen again this year? In the last few days, the situation has started improving. Over the weekend, water levels were edging towards normal, though they're set to decrease again later in the week. The good news is it's unlikely to return in 2023.
Originally, it was thought that 5th century Venetians were forced to flee from the mainland because of conquerors and invaders. The idea was that building Venice on top of its lagoons provided protections that the original settlers sought after.
The depth of the water in Venice's canals varies by canal, whether dredging has been done to remove silt and sand in that particular canal, and the tide levels. Most canals are 5 to 6.5 feet deep, while the Grand Canal is deeper, at about 16.4 feet.
It's not possible to raise the city of Venice, therefor the question how much it would cost is obsolete. However there are alternative plans. Venice is in a lagoon, a sheltered part of the sea. It would be possible to control the water level in the lagoon by building dams and pumps at the sea openings.
A recent climate change study has warned that Venice will be underwater by 2100 if the acceleration of global warming is not curbed. This is because the Mediterranean Sea is expected to rise by up to 140 centimetres (over four feet) in the next century.
However, historically speaking, Venice was not always a city built on water. The origins of Venice date back to the 5th century when people from the mainland, fleeing the invading barbarian tribes, sought refuge in the marshy lagoon of the Adriatic Sea.
In the 5th century, people fled their homes to avoid barbarian conquerors. A marshy lagoon was located just off the mainland and protected from the barbarians who would not cross the water. As invasions continued across Italy more and more people fled until eventually, they realised there was a need for a new city.
In Venice, 78 barriers form a dam separating the Venetian Lagoon from the Adriatic Sea. The barriers are split between four gates among the barrier islands that are the access points to Venice.
Built on a muddy lagoon with inadequate foundations, the ground beneath it has slowly compacted over time. This, combined with the groundwater being pumped out from under the city and a gradual rise in sea levels, has resulted in the city very slowly sinking.
Venice solved the problem most ingeniously—with a tidal floodgate system called MOSE. Its steel gates float up as they are filled with air, sealing off the city from a rising tide. No one, not even the Dutch—legendary for fighting back the sea—has a system like MOSE. Leonardo da Vinci would have been proud.
With current projections, there is a possibility that Venice will be underwater by 2100. While the city may still be visible at it's highest points, the water levels may be so high that it will be uninhabitable. Between 2000-2015, the city only 'sank' approximately 3.75mm.
They did this by digging hundreds of canals and using wood pilings to keep the banks in place. There wasn't enough land for all the houses they needed, so they had to find a way to make marshy areas strong enough to build on. To do this they outlined areas in clay, then filled them with soil from the lagoon.
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Introduction: My name is Msgr. Benton Quitzon, I am a comfortable, charming, thankful, happy, adventurous, handsome, precious person who loves writing and wants to share my knowledge and understanding with you.
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