The first traces of the port of Saint-Valery-en-Caux, nestled in a valley between Dieppe and Fécamp, date back to 990. A refuge for herring fishermen, the city became, in the middle of the 19th century, a vacation spot destroyed in the three-quarters by the Panzerdivision (armored division of the Wehrmacht
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of General Rommel in 1940. Today, the city has nearly 4,000 inhabitants and must face another major risk, climate change.
Already threatened by runoff from the plateaus, the municipality is currently testing an anti-flood buoy to protect against rising sea levels.
Indeed, Saint-Valery-en-Caux must first look behind it, “because we are the outlet of a dry valley which drains 100 km2 of crops upstream by runoff from the plain.
It began in the mid-1980s and twenty dams with a total storage capacity of 300,000 m3 were built to contain the mudslides and regulate the flow into our inner harbour.
This is a reduced risk, however with major floods like those which have just occurred in Hauts-de-France, it would overflow and all the main streets would be affected.
All this is integrated into our urban plans,” indicates Jean-François Ouvry, the mayor and member of the IPCC Normand.
Great first with the tide of 117 expected in March
With a coastline two kilometers long with cliffs and a pebble beach, the seaside resort must also pay attention to the vagaries of the Channel, “with its tides and its storms”.
“When the coefficients exceed 100, the water flirts with the edge of the Quai de la Batellerie where the Maison Henri IV is located, classified as a historic monument.
It is the lowest in the department.
So, when the wind comes from the North-West and there is a strong swell, in addition to the pebbles flying, waves of 1.5 meters hit the foundations.
With each episode, it is more and more visible and it will continue to grow.
The floods keep coming,” notes the councilor.
This is why, installed by SML76 (Seine-Maritime Coastal Mixed Union), for several weeks a box has been enthroned with a floating barrier inside.
“Designed by the Danish company Flood Frame, this anti-flood buoy rises with the water level and deploys a plastic film which is pressed against the walls.
It is a proven technique for river or river flooding.
Now we are testing it in a choppy environment with waves and swell.
Will it rise fast enough?
We are giving ourselves six months to validate the experiment and the first major nature test will take place around March 12 with an expected tide of 117.” However, for Jean-François Ouvry, this enters into short-term strategies.
“Our communities do not have the means to expropriate, buy back and raze”
According to the Norman IPCC, the Batellerie quay will be under water for at least 70 days per year in 2100, “and perhaps more often”.
“Sea level rise is inevitable.
One meter by 2100, on one condition: Antarctica does not move.
Our scientific friends say so, otherwise it's at least two meters.
Therefore, Saint-Valery-en-Caux will be affected.
This is why we must react in two stages.
In the short term, with temporary measures to limit the damage.
This is what we are testing at the moment.
This can give us time to think and find the financial means to put in place.
Will there be a Barnier type fund
(Editor's note: created in 1995 for compensation for properties highly exposed to natural disasters)
managed by the State which does not yet exist?
Because our communities do not have the means to expropriate, buy back and raze.
The cofferdams will no longer be enough,” says the mayor.
And, of course, there is the long term, where, according to the elected official, for his municipality and that of the Seinomarine coast, “it will also be necessary to adapt agriculture in order to limit runoff.
That being said, we know that the level will be one meter higher and that our houses will have their foundations in the water.
What do we do ?
Do we maintain, dismantle, move?
It will be necessary to transform part of the city.
This is why we must already imagine things and provide information.
Our Quai de la Batellerie will be the first to disappear in Seine-Maritime.
The SML76 was created so that elected officials can organize themselves and prepare mentalities, because we will not be able to hold back the sea. This is not a figment of the imagination,” Jean-François Ouvry is convinced.