How have they saved Venice from the waters?
With a combination of natural restoration, "grey infrastructures", such as the dunes that protect against flooding and slow down the energy of the incoming water; and the engineering of mobile submerged barriers.
His predictions three days before the floods have been providential.
Having a precise and correct prediction of when the flood will be - storms, winds, currents, sea level on the coast -, we can start the MOSE containment system.
Does it take three days to contain the waters?
Three days, yes; but the submerged mobile barriers are saving Venice, even if they complain that it is very expensive engineering.
I remember that the flood and the end of Venice was a recurring chronicle.
Well, there are no more chronicles of correspondents about the end of Venice with a wonderful and expensive work; but she was the only one who could save her as long as we had an accurate weather forecast three days in advance.
Wouldn't forecasting a storm and flood just a day in advance save Venice?
No, because the system requires these three days of anticipation to give the barriers time to deploy and be effective.
Well congratulations: you save Venice.
Now we need more accurate and specialized forecasts to also defend our coast: all the coasts of the Mediterranean are in danger and more so, theirs.
Why else ours?
Because the Atlantic through the Strait of Gibraltar influences them more.
This year, like almost everyone, we have run out of sand: how can we save them?
With the collaboration of engineers, oceanographers – rivers and their currents and the drag of silt are essential – and meteorologists. If you know that in seven days a big storm will hit your coast, you can propose engineering solutions to protect it.
Put running sandbags?
It is also necessary to restore natural assets, such as dunes or corals, that human intervention, with the construction of ports or other infrastructure, and climate change deteriorate. Human engineering is not enough; we need that of the planet.
Do we still have time to recover our beaches?
Until 2010 scientists, engineers and entrepreneurs, managers and politicians, we worked without organizing. In the last decade we realized that without collaboration there would be no salvation. The case of Venice and its providential public-private collaboration can serve for others.
Will we get better weather and ocean forecasts?
But we need data to make the models work. We need observations and I am sure that with them artificial intelligence will make a huge difference in prediction and engineering.
What do we need most urgently?
Europe must get to work immediately to have a sediment balance budget.
Have all the sediments of European rivers and beaches quantified?
We need to calculate the sediments of rivers, reservoirs, coasts... Know if they are available to move and transport them and how they flow with the rivers.
Is it possible to measure them all?
Today we have the tools to prepare this budget that would allow us to deploy a system of monitors that would save beaches, coasts and deltas.
I admit it's better than sacks.
Better than truckloads of sand, believe me, is planning, engineering and ecological restoration.
Why are we losing sand in Catalonia?
We are losing beaches all over the planet, because they are like living organisms and climate change affects them, but also because of changes in the seabed. In the bed of the river Po, which I know well, we are running out of heavy gravel and instead have more and more fine sand.
Does the coast degrade without gravel?
Due to human action and swamps for electrical energy, coarse gravel is transformed into fine sand; but there are many other factors that combine to destroy the beaches, such as changes in temperature that modify the vegetation of the bed that fixed the sediments or destroy the corals that stopped flooding. Do you know which is the best truck to carry sand?
Who?
The ocean itself... if we restore its balance.
And if not?
If it continues to degrade... I am told by the UPC that on the Catalan coast the sea level rises by 10 mm a year.
