The president of the Order of Geologists explains to SIR: “Removing the waters from critical slope areas is the first action to be taken. The ditch is the first prevention, but now due to the intensive cultivation in agriculture and the few resources of the Municipalities, maintenance is scarce”
The bad weather emergency that has particularly affected Romagna in recent days has highlighted a problem that has always accompanied the Apennines: the phenomenon of landslides. Many areas are still isolated, where there are homes, businesses and farms that receive supplies with helicopters. We talk about all this with Paris Antolinipresident of theOrder of Geologists of Emilia Romagna.
How many landslides have occurred these days?
Official data speak of 370-380 landslides, but every mayor says that there are hundreds of landslides in their municipality. There may also be an emotional evaluation but actually the landslides are many more than 370-380:
we are certainly over a thousand,
because landslides are not only the big ones, but there are many along the roadside or that have destroyed portions of the road, but tens of thousands of euros are needed to repair them. The landslide discourse is still completely open.
Can new landslides be predicted even without further rainfall?
First, there are territories that are still not reached. The mayors themselves say that there are landslides currently in motion. It is clear that with the ground so saturated and soaked in water it is normal for there to be some landslide slope activation that we had not previously seen, perhaps there were the “symptoms” but there was no slipping yet. So, there may be new landslides, but going forward, with the summer heat, the ground dries up and the likelihood of new landslides decreases.
But were all these landslides predictable?
Our territory already has a hydrogeological instability in itself, a few rains are enough, sometimes even summer storms, to witness slope erosion or landslides. With rainfall like the one we have had, with two successive important events on 2 and 3 May and 16 and 17 May, these soils, which are mainly made up of clay and more or less cemented sand, together with water make up a deadly mix: it rains, the water infiltrates the ground through the porosity, the fissures and fractures that exist in the ground itself, descends deeply, reaches certain surfaces and lubricates them, saturates the ground, which increases in weight, and – not forgetting that we are on sloping slopes – all this causes the landslide, which can be small or even very large. Landslides, in fact, are of many types: a simple flow or a large landslide that is almost invisible to the naked eye but moves slowly.
Is prevention normally carried out in such a risky area?
This is an area where there is a lot of hydrogeological risk, a lot of work is done all the time. In the mountains, to prevent landslides, ditches must be made to regulate the waters: ditches both in agricultural areas and in country roads. Removing the waters from the areas of critical slopes is the first action to be taken.
The ditch is the first prevention: it must drain well, the water must not stagnate.
The less water we throw into the soil, the better.
But has there been prevention in the past?
As far as agriculture is concerned, in recent years there have been cultivation methods that do not help combat hydrogeological instability: I am referring to intensive cultivation, to processes that are carried out on vast extensions even on the hills, because by now we think in terms of quantity and never quality. There is no longer the farmer who goes to the mountains with a hoe to tidy up the ditches, to clean them, to empty the stagnant water; now we work with tractors, we prefer a job that must cost little and produce a lot. As far as the road system is concerned, the Municipalities no longer have the roadmen who take care of the continuous maintenance by going around the streets with the shovel to maintain those small instability. Sometimes buffering certain situations and taking care of water regulation in small streets can help. Now, however, this type of work is contracted out, ditches are made once or twice a year. If in the meantime the ditch closes, however you have to wait for the next intervention of the company that has contracted the execution of the works. These are the small works. Then in the mountains every time you intervene to fix a road a lot of money is needed: if a road collapses for a small stretch of a few meters, on the sea side, as usually happens, and half the lane disappears, intervene and carry out structural works to restore the viability really requires a lot of money, but small municipalities do not have many resources to deal with the problem.
This emergency can be an opportunity to do many works which will benefit the territories.
When it rains so much in such a fragile area, the damage is enormous. On the other hand, it was impossible for such extreme events and, honestly, it was also impossible to secure the whole territory.
Volunteers in Gambettola (Photo Corriere Cesenate)
But will it be possible to restore the situation to how it was before the bad weather and landslides?
No. In some cases, the layout of the roads will have to be changed when it is estimated that some roads cannot be recovered and therefore for a few kilometers the layout will have to be done elsewhere. On the other hand, the history of the Apennines and landslides goes hand in hand.
Landslides have always been a characterizing element of our Apennines in history,
in the past in correspondence with exceptional climatic events: if we look into history as long as there are documents attesting to this, when there is such rainfall, huge landslides always occur. The last heavy rainfall we had in Romagna with the rains of 1939 caused as many important landslides, even in the nineteenth century we had large landslides in correspondence with particularly rainy periods.
Sarsina, road interrupted due to landslides (Photo Corriere Cesenate)
Will it now take a lot of expense to restore or make new road layouts?
Absolutely very big. Certain roads, which used to be very close to a river and have been eroded, would be better not remade where they are now. Furthermore, we must remember that apart from the main road system, the provincial and state roads are all roads that in the past were mule tracks: first the horse or mule passed through them, then they were widened for carriages, in the end they were widened even more to the truck. So, over time they have undergone several changes.
(Photo Corriere Cesena)
What kind of work will have to be done now to overcome this emergency?
In the immediate future, where possible, the viability is restored by intervening on all those small landslides of escarpments that have occupied the roadway, cleaning with the bulldozer and reopening the roads. Let’s not forget that there are homes, businesses and farms that are still isolated. Both food for those who live in those areas and feed and hay for farm animals are supplied with helicopters. We are still in full emergency and it won’t always be possible to go ahead with helicopters, so the most urgent interventions are those to reach isolated areas. In a second moment it will take a big design work both to make the slopes safe, and to design small sections that have broken due to landslides, and to design wider routes.
And how long will it take to restore the situation?
Years and years. In fact, we must also consider the work of organizing the rivers, we will have to widen the banks, redo them. There will be design work for an entire generation.
(Photo Corriere Cesena)
Are you afraid that once the emergency is over, the spotlights on Romagna will go out?
Now there is great attention, but I am convinced that once the emergency is over we will forget what happened. Every Government, regardless of political colour, when a striking event occurs as has now happened in Romagna, waves the flag against hydrogeological instability, but then, once the emergency is over, the wind that makes that flag fly ceases.