Xynthia related disaster at La Faute sur Mer (Vendée, France)

Transcription

1 Picture on the official prefectoral website (State local representative). Geological map (1975) Buildings and dikes as in Xynthia related disaster at La Faute sur Mer (Vendée, France) 12 mn A geopolitically an culturally driven disaster, challenging local management.

2 STRUCTURE 1. La Faute sur Mer : a high intensity and unusually located flood event in France. High frequencies of floods in France, with low mortality mainly concerning mediterranean areas. But : La Faute sur Mer : 29 dead on the atlantic coast. And a new type of zoning (in the making), raising strong local oppositions. Yet : Flood risk and storm surges are nothing new in La Faute sur Mer... How to understand such a disaster? What can we learn from it? 2. Preparing the disaster on the long run : a disaster geopoliticallly and culturally driven. Increasing trend towards disaster : very recent urbanization on flood-prone areas, with low-rise buildings, accommodating a greying and increasing population. What about political regulations, national and local? Political regulations (national and local) increased the trend towards disaster. Why? The main keys? A local community of landowners with poor land reserves on a marginal and recently created municipality under touristic pressure.

3 1. La Faute sur Mer : a high intensity and unusually located flood event in France. In France, floods have the highest frequencies among «natural» disasters. But low frequencies of storm surge related floods. Yet, during these events, French experienced low levels of mortality, hardly mapped. Mortality peaks used to be found in southern part of France. La Faute sur Mer, with 29 dead, doesn t fit the rule. (Vinet, 2007) 5 dead Floods Risk and related Management of mortality current and future Storm in Languedoc-Roussillon, Surges France,

4 The french State decided to issue a strongly contested «zone of extreme danger» («black zone» then «solidarity zone»..) and mapped it officially. 674 homes supposed to be erased. The official zone of extreme danger in La Faute m Landowners claims against the new zoning, July Original scale about 1/15000 Municipal council deliberation register (27 mai 2010) tracks back official damages declarations for: 324 main homes; 1103 second homes; 475 mobile homes»storm SURGES CONGRESS 2010«Once again, La Faute is more concerned Risk and Management of current and future Storm Surges than other municipalities.

5 Yet flood risk is nothing new (if not obvious) in La Faute sur Mer Lay river outlet Atlantic ocean Municipal campground, L Aiguillon (another municipality) Newly built estates behind dikes General picture from La Faute municipality, displayed on a wall of the municipal council room (about 1980). Risk and Management of current Let s and future notice Storm Surgesthe trend to gain land by diking.

6 Geological map notice mentions flood risk, dykes, and former storm surges m Coastal sandy ridge disrupted by Xynthia Old Lay river outlet Grounds gained by diking, heavilly flooded by Xynthia storm surge Dikes dating back to 1929 storm surge L Aiguillon sur Mer geological map (1975) Original scale 1/ Why such a peculiar disaster?

7 Favouring disaster : very recent urbanization on flood-prone areas, filling up the «zone of extreme danger» Dikes Roads on dikes P. Pigeon & A. Paillet, 2010 Sources :1963 and 1977 cadastres, 1984 POS, La Faute archives, municipal council deliberations.

8 Favouring disaster : low-rise recent buildings. Aerial picture of La Faute about Both estates didn t exist at that time. Courlis estate (29 february 2010) and Ostrea estate (50 metres northwards; 29 June 2010) seenrisk from and Management the of collective current and future Storm dike Surges («digue syndicale»).

9 Favouring disaster : a greying and increasing population Evolution Evolution Landowners Second homes Detached houses Retired people % 37% 73.9% % 46.1% % +9.1% A population of landowners mainly living in detached houses used for retirement Strong building pressure accommodating a greying population : vulnerability increases Demographic growth Home growth Percentage of women over % % +11.3% +45.6% +6.4% Age distribution Nombre de morts of liés dead à Xynthia people et à La Faute in sur Mer La Faute More than 2/3 of dead people (29) were over 60 years old Nom 2 1 What about political regulations that should Risk have and Management curb the of current trend and future towards Storm Surgesthe disaster? 0 Moins de 10 de 10 à 20 de 20 à 30 de 30 à 40 de 40 à 50 de 50 à 60 de 60 à 70 de 70 à 80 de 80 à 90 Data : La Faute council deliberations register.

10 Political regulations increased the trend towards disaster Original scale : 1/ Lay L Aiguillon 2002 Atlantic ocean La Faute Lay River 27 years needed for a risk prevention plan enforced by the french state 2010 Risk prevention plan, Map juridically enforced by prefectoral decision, 8 June Difficulties to enforce a strongly contested plan contributed to the disaster. In France, the»storm first SURGES PPR CONGRESS (PER 2010«at that time) date back to Municipal campground and more than 100 buildings in red zone area, which reduces land reserves

11 A municipal POS-PLU favouring low-rise building on flood-prone areas It favours low-rise buildings (<9m) and local construction. Building heights regulations directly mentionned on the 1984 PLU map, which is uncommon. This political choice increases land building pressure and challenges PPR map. Low-rise buildings heavily flooded behind the dike, seen from the port, July Local political choices and strong conflict between 13 french - 17 September, State 2010 and municipality favoured La Faute disaster. WHY?

12 The main key? A local community of landowners with poor land reserves 1977 cadastre 1963 Cadastre, original scale 1/1000 Cadastre constraints reduce (among others...) land reserve for building (municipal size : 7 km2). Local landowners created AFU «land associations for urbanization». Powerful NIMBY local pressure on La Faute municipal council. They favoured estates of low-rise detached homes or buildings. Small scale land plots unfitting building pressure (July 2010)

13 on a marginal and recently created municipality La Faute has been created in 1953 only Formerly it belong to La Tranche municipalty La Faute sur Mer doesn t belong to any intercommunality association. Local risk management doesn t impact any other major municipality. Until 2010, stakes ranked local if not secondary at the national scale. Red : La Faute sur Mer Yellow : other municipalities not belonging to any intercommunal association. Blue : municipalities belonging to a municipal association. Seen from the french State (before the disaster...) : La Faute : a marginal municipality with national stakes ranked low

14 The geopolitical and cultural side of the disaster. Challenging the absolute relevance of disaster local community management. Xynthia revealed the geopolitical preparation of the disaster : conflicts between french State and a municipality about building regulations and zonings, under conditions of low stakes at the national level (PPR -risk prevention plan- enforced in 2007 only). In this specific case, the small extension (7 km2!) of a newly created municipality (1953), and the will to promote low-rise urbanization (local landowners lobbies) stress on the cultural conditions of the disaster. Disaster as resulting from positive coevolution (local landowners lobbies will to build low-rise estate houses reducing even more municipal land reserves for building and increasing lobbies political pressure in turn), pushing to build even more on hazard-prone areas. Possible links with complexity theories. It challenges the absolute relevance of reducing disasters while strengthening local community decision powers...

15 Cap-Haz net WP1 report, 2010, pp

16 Cap-Haz net WP1 report, 2010, p. 34.