Increased risk of flooding. While a recent public report by the Court of Auditors highlights the lack of preparation of the Ile-de-France region in this area, the problem has been tackled head-on, for many years, in the departments of Aisne and Oise. In 1993 and 1995, the Oise had been confronted, one after the other, with historical floods. Today, the Etente Oise-Aisne, a public establishment which deals with the management of floods and floods, remains vigilant.
“We cannot compare ourselves with Ile-de-France, which has very different problems because of urbanization, immediately points out a spokesperson for the Entente Oise-Aisne. But it was necessary to act after the disasters of December 1993 and January 1995 which each time caused 100,000 victims in approximately 200 municipalities. »
In this sector, we are far from the violence of the Mediterranean episodes and the Cévennes storms which rage in the south-east of France (at least 45 dead and 8 missing since 2015, according to the Ministry of Ecological Transition). Less dangerous, the Oise is nonetheless a capricious river. And it was the collective awareness, in 1995, that triggered major investment projects.
Two flood control dams have thus been built in the Aisne. The construction of a third, smaller one is planned for 2023-2024, in Beaugies-Berlancourt, between Compiègne and Saint-Quentin. “The cost of the studies and works for the structure in Proisy, for example, was 8.2 million euros. The damage that was avoided during the January 2011 flood is estimated at 70 million euros,” says Marjorie André, director of the Oise-Aisne agreement.
In the department of Oise, another structure, said flood reduction, was designed around Longueil-Sainte-Marie. It is quite simply a question of reproducing the natural expansion zone of the Oise by creating weirs in charge of storing water on agricultural or wooded plots. The water is released later when the risk of flooding has passed.
Preparedness for crisis management
“These strategies are implemented by communities to reduce the risk and these facilities have been created to protect property and people,” continues Marjorie André. Today, the actions are continuing and focus in particular on raising public awareness and preparing for crisis management.”
Thus, a new aid device, baptized Inond’action, makes it possible, after diagnosis, to finance 80% of protection work for individuals or small businesses. “A dozen people have already started work such as raising a boiler or fixing a garden shed to the ground, for example”, we explain to the Oise-Aisne Agreement.
Planting of hedges and weirs
Moreover, this fight against floods extends to the effects of runoff during major storms. Because after the high heat of summer, the risk is even higher this winter. “We are carrying out actions with farmers to replant hedges or fascines, kinds of intertwined branches, as in Saint-Pierre-les-Bitry, in the Oise, underlines the Entente. In September, a violent storm hit the town. The mayor was delighted with these arrangements which prevented the mud from rolling down. »
This fall, the Hauts-de-France region has not yet experienced major flooding, except in certain towns on the Côte d’Opale, in Pas-de-Calais or in Abbeville, in the Somme. But the critical period is often between November and March.
“If the February 1995 flood were to happen again today, the flooding would be much less for the municipalities benefiting from the regulation works which concern the departments of Oise, Aisne and Val-d’Oise, assures Marjorie Andrew. Water levels would be reduced and damage to housing and activities would therefore be less significant. »