By
Géraldine Lebourgeois
Published on
May 21, 2024 at 6:58 a.m.
; updated May 21, 2024 at 7:04 a.m.
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In front of the instability of the coastline, in front of coastal erosion, it is clear that it remains difficult to enter fully and collectively into a new regional planning logic.
For years already, the findings and declarations of intent have been there. Reflections, meetings, programs and projects have multiplied in an attempt to establish suitable strategies.
Already several properties in danger
Cerema (Center for studies and expertise on risks, environment, mobility and planning), a public establishment which supports the State and communities in these issues, has studied the consequences of the retreat of the coastline on the French coast by 2100. The Channel is among the six most threatened departments, with almost 20,000 housing units affected by the retreat of the coastline.
In these projections, 5 housing units and 22 business premises (shops, hotels, campsites, offices) are already threatened in the short term, by 2028, for a value of more than 2 million euroswhile protective structures (dykes, riprap, etc.) are considered to still be effective in this scenario.
In that for 2050, the machine is racing and the figures increase to 309 housing units and 48 premises threatened in the Channel, and a loss of 42.6 million euros. For 2100, in support of the projections of the IPCC (Intergovernmental Panel on Climate Change) which estimates that sea level will rise by more than a meter, and by integrating this time that the defense works will no longer be effective, 18,748 homes and 2,146 premises would be threatened, for a value of more than 3 billion euros…
Identify places to act as a priority
This study, of which the share of uncertainty is recognized (read our box below) is an aid to reflection led by the Coastline National Committee, of which the president of the Manche departmental council is a member. Jean Morin recalls that the Department is present and acts to protect the coastline. He voted for a budget of “ 8 million euros to liven up the regionraise awareness, raise awareness.
Everyone is affected by rising sea levels.
A scenario “conditioned to major storms”
Supporting communities with other experts such as the BRGM (Bureau of Geological and Mining Research), Cerema explains the difficulty of estimating the challenges of coastline retreat, even in the short term, because it is “largely conditioned by the effects of major storms or the cumulative effect of series of storms” (Source: cerema.fr).
“It is almost certain that this type of event will occur again in the coming decades (and more frequently due to the effects of climate change), but it is much more difficult to comment on the occurrence and consequences. chances of reproduction of such phenomena in the coming years”, it is added to evoke the part of uncertainty.
“The position of the coastline could retreat more quickly than estimated during a major event, or, conversely, not change or change later in the absence of a significant event. »
156 monitoring stations
Also the tools are multiplying to approach the most plausible scenario. The Manche departmental council has also been involved for several years and there is a local “coastline observatory”. To date, 156 monitoring stations have been installed along the Channel coast, in areas already identified as sensitive, explains Clément Nalin, coastal natural risks and flooding engineer.
In a policy focused on sustainable management, the departmental council supports the need to adapt the defense and protection strategy to the specificities of each site and its evolution, in support of scientific and rational methods. “Be careful of the choices whose long-term consequences we suffer,” says Clément Nalin, who also announces the soon establishment of citizen observatories, where everyone will be able to contribute to monitoring.
The latter hopes to be able to work even more with the municipalities to identify the places where to act first.
Because each new storm no longer goes without its share of significant damage. During the last assault of strong winds coupled with strong tides, On April 9, 2024, with storm Pierrick, constructions and sea defenses suffered once again. Again, dune cords were mutilated in many places.
Municipal decrees have been issued to prohibit access to the seaside, or even to prohibit access to property in danger. It is then a question of security orders, by which the owners and occupants are prohibited from accessing the house. For the moment, these municipal decrees are rare and only concern second homes, but until when?
While waiting for effective sustainable management, plans are being drawn up and we can expect a boost in 2025 to “identify the consequences of the evolution of the coastline within 30 and 100 years”. In addition, to the decree establishing the list of municipalities “whose action in matters of town planning and development policy must be adapted to the hydrosedimentary phenomena leading to coastal erosion”, a list that the State is preparing to update, there are 40 in the Channel as of July 31, 2023.
Can we wait another century?
For the moment, communities (municipalities, intermunicipalities) are mapping the areas of exposure to horizons 30 years and 100 years, maps which will be integrated into town planning documents. The State is committed to providing them with tools to support them in this process (technical and financial support).
The objective is to improve knowledge and share information in the face of phenomena which will accelerate, in a obligation of transparency, in order to make choices, develop local coastline management strategies, evaluate exposed assets, prioritize issues with full knowledge of the facts, and consider “real lease of adaptations to coastal erosion , possible exemption from the coastal law to manage relocations, financing attached to the management of the coastline”, as it was exposed on April 12, 2024 during the council of the Cotentin Urban Community. The implementation of PPA (development partnership project), such as the one signed in the territory of Coutances Sea and Bocage (PPA “Between two havens”, there are only three currently in France) and PPRL, is also expected to become widespread.
Isn’t it high time to enter into the concrete together, which will certainly require opening the financial floodgates…, knowing that the sea and climatic phenomena, which remain largely unpredictablewill not wait after the procrastination.
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