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Flood risk management: cases studies in French Mediterranean area

Stéphanie Defossez1, Tony Rey1, Freddy Vinet1 and Laurent Boissier1 1UMR Gouvernance, Risques, Environnement, Développement (UPVM/IRD), 2196, bd de la Lironde, bât 4, 34980 Montferrier sur Lez. France.

Abstract. In France, for a long time, flood risk management has only oriented to controlling flood hazard with structural measures such as dikes. But since 1990’s many events have proved they have not totally efficient measures. So, institutions decided it’s necessary to manage flood risk with others ways like prevention. Risk management is so organize about holistic policies with different stakeholders and societies exposed at risk. Our study have the aim to demonstrate through several examples how flood risk is manage in French Mediterranean area. Post event feedback permit us to evaluate damage and crisis management. This method is use for show if this strategies is efficient or not. This study demonstrate how is risk management in France. Regulations are they efficient, so have they an influence about the reduction of deaths and damages? Individual measures are they more important than collective action? Finally, what policies and strategies are used and effective? The main results about cases studies show that natural event has most important that publics policies and it determines preventive policies.

1 Introduction 2 Evaluation of effectiveness to risk management prevention Since twenty years in France, risk management move with a most important place for preventive measures. But Since two decades, the flood risk management the global risk management, witch define like a changes. In this context we want to estimate the management include all the stakeholders and many kind effectiveness of the proposed measures. Risk of measures, is not so easy. In fact, many time it’s so management through protection includes from now more difficult to develop the measures with societies to local methods of prevention and preparation for crisis scale. management. Prevention measures are organized around Our studies presents in this paper concern mainly actions on issues, regulation for land use, and reduction preventive measures because structural measures can’t be of vulnerabilities through Risk Plan Prevention. They only use for risk management. This measures wasn’t also organized around the information of populations at always efficient. Preventive measures are presented as risk and memory of the risk. So, people remain vigilant additional measures that can include all stakeholders with and can prepare for a potential crisis. This evaluation collective and individual measures. We particularly study aims to show a report of the measures but also then be Risk Prevention Plans because they are the main able to propose adaptation strategies. Adapting to risk measures concern prevention. It contains regulation land allows to envisage reducing the damages and especially use and mitigation measures, so we study both of them. the deaths. But information to populations about natural hazards and risks and preparation for crisis management are also very important. Institutional rules and laws was not always The valuation method based on the comparison applied on localities because they was not accepted by between expected objectives and reached objectives [1, 2, stakeholders (institutions and populations). So it’s often 3]. the event witch activate prevent individual and collectives It was possible with the analysis about the Risk measures. Prevention Plan (PPR in French). It’s a document witch This paper show certain results of several studies regulate land use liable to natural hazards and decided to focuses Mediterranean flood but also examples on French authorize or not buildings. Its objectives are to control the coastline concerned by storm surges. In fact some of future land use but also the existing with the main results are common about flood by river or sea in France decisions about mitigation. But this plan concerned all the stakeholders and people who live in areas exposed to natural hazard. So, after a survey with institutions, we also submit the people to a survey. The aim was to value a Corresponding author: [email protected] The European Physical Journal Conferences his knowledge and awarness about flood risk and different time, so we show the evolution of risk management flood risk. management including the arrival of new preventives We have realize several surveys about flood. One measures. For example Municipal Safeguard Plan (PCS survey concerned about 300 people in Cuxac-d’Aude and in French) since 2004 or the information buyer which Coursan in 2004 and in 2015 [3; 4] in low plains of mandate since 2006 to inform if the building is on risk department Aude (Fig.1). area. Even if we don’t have much backward perspective about these tools, it’s possible to show the advantages and the limits. The methodology also includes an assessment of human and material vulnerabilities based on vulnerability criteria (Table 2) used in other previous studies [7, 8]. This evaluation allows to estimate potential damages and make the link between the effectiveness of preventive measures including reducing vulnerabilities. This report also allows to adjust the adaptation strategies and mitigation.

Criteria Indicator

Figure 1. Location of cases studies -State of walls Material Type and state of -Tightness of vulnerability built This people was suffered with flood river Aude in walls november 1999 (many damages and five deaths in -Over 80 years Cuxac-d’Aude). We follow-up while several years this Human Age old territory about flood risk management gave us the vulnerability Health -Disable opportunity to lead the same survey with the same person localization (addresses). We see the evolution of the Table 2. A few examples of vulnerability criteria and indicators perception of populations about risk knowledge and risk management. An other survey concern 110 persons in We work about several cases in French Grabels following flash floods on October 2014. Mediterranean where flash floods often occurred. Flash Additional on the surveys, we done as soon as floods are frequent and cause damage and deaths as in possible experience feedback especially after flood events 1999 (35 dead), in 2002 (24 dead) or in 2010 (26 deaths) in the Mediterranean area [3, 5, 6] (Table 1). Except for in the south of France for only these examples. The the events of 1999, which was study a few years later, natural event has high flow rates, high water heights and experience feedback consisted to go on the place rising fast level water. So are brutal events. occurred the flood. We value the damages but also the We study Mediterranean territories exposed to these floodplain and water levels, then we estimate the hazards whitch are highly urbanized. They knew strong effectiveness of measures, in particular with our own and fast population growth during the 1960s. But observations and with interviews. urbanization was made in the floodplains so in case of events, the damage and the deaths can be very important. Although there are small towns multiplying the frame Date of event Locate exposes people to risk. The city of Grabels (Hérault) for (river flood) example shows an extension of its urbanization, in part in Department of Herault, flood risk area (Fig. 2). November 1999 Aude, East Pyrenees and Lozere

June 2010 Department of Var

Lamalou-les-Bains September 2014 (department of Herault) Grabels October 2014 (department of Herault) [ Table 1. Feedback of natural events in France particularly French Mediterranean area.

These analyses on field study are realized to evaluate the global effectiveness of risk management and crisis. We use the same methodology explains before as the comparison between expected and achieved objectives. They also allow to show the damage and then Figure 2. Growth of urbanization to Grabels between 1960s and purpose strategies of reduction damages and today in part in flood risk area vulnerabilities. We led this experience feedback on Title of the conference

This studies cases allowed us to present here several this is the event that has influenced mitigation and less results about effectiveness of preventive risk regulation. management.

3 Preventive measures are recent and difficult to apply

3.1 Risk Prevention Plan is like a constraint?

3.1.1 A tool that come too late This regulatory tool has like main aim to regulate land use and purpose mitigation. So the assessment of this measures focused on the analysis of land use. In all cases studied, the two key parts. If we follow the Figure 3. Adaptation measure to flood (half floor) in Cuxac- evolution of construction, Risk Prevention Plan slows d’Aude (Defossez, 2009) down construction but do not stop the development of the town. This is the opportunity for municipalities to occupy We make surveys in Cuxac-d’Aude with 188 the free spaces with urbanization on areas outside the persons. The results show that more than half of the floodplain. But there are also buildings in the blue area houses don’t have one floor so they are vulnerable by (for remember flood risk area in PPR is divided in 2 flash flood. Homes are not built to be appropriate for the colors: red for the high level risk and blue for low level risk but dependent on other financial factors or lifestyle risk). In this area the buildings are allowed but they [10]. But we can estimate with this type of house that should be built with requirements (for example building damages and deaths are more frequent. An other survey floor above the high level water already known). This can was made in Grabels [11] and 10% of respondents said be considered like adaptation to risk. But it is difficult to the possibility of building a half floor or floor refuge. say, however, that the measure is effective because there They want to protect they self and so do mitigation. Even is no means to verify that the requirements are done and this decisions are also take following the crisis and not respected. In the Aude, interviews with elected with regulatory tools. These people had not considered representatives have shown that these audit lack do not before 2014 to build a floor. Of course this is still encourage people to respect for a long time these potential, we actually do not know how many people will requirements. Also instructors services are "very reluctant really do the work. The cost of this measure can be a by those relating to the construction and completely brake. Institutions will invest in such this measure. opposed to what his services are called upon to make any Financial factor is not only the problem, we consider the control even of construction" [9]. measure is not accepted by stakeholders and protection Then, the measure could be effective in the future and structural measures are still considered like the only but for already built that’s too late. Indeed, the buildings responses to flash flood. But for the moment the in floodplain have been built since the 1980s when the reconstruction at the same is the most frequent [12]. land use regulation was not a priority. The main limitation we make here is the lack of feedback from the In general, the risk prevention plan is seen by local regulations, so these buildings in floodplains will remain officials and residents as a constraint [3, 6, 13, 14].That in the floodplains. But if we can’t act on existing issues can affect the development of the town and the resale of Risk Prevention Plan purposes to reduce vulnerabilities. homes for people. So it’s difficult to accept Risk Prevention Plan and, they are not effectiveness. And while the long time procedures construction can continue. 3.1.2 Mitigation influenced by the experience of The aim of the plan are not achieve because it not reduce event more than RiSk Prevention Plan the stakes. In the various cases studied in our research, the measure does not appear effective because the plans Our case studies (Var, Grabels and Lamalou-les- arrive to late and their application is difficult because Bains) showed that few mitigation measures was used local societies and territories have other priorities (like following the approval of the PPR. Aude and particularly local development for example). in Cuxac d'Aude, analysis of building permit allowed us to notice adaptation. The main measure was to build half The regulate land use cannot be performing to risk, a floor or floor refuge. But if we analyze the period which especially as mentioned above regarding the existing. It these measures were taken, PPR has not much influence. seems so essential to complete that with others preventive In fact, the low plains of the Aude suffered serious measures like crisis management and planning with the flooding in 1999. Data analysis therefore shows a growth aim of saving lives to better organize crisis management of these measures immediately after 1999 and it and planning but also the information about risk. decreases after 2000 (Fig. 3). That makes us think that The European Physical Journal Conferences

3.2 Awareness of risk for saving lives We believe that informing the population about the risk involved in the preparation for crisis management so we treat both measures simultaneously. They depend on each other and participate in both harm reduction and flood victims.

3.2.1 Preventive information The preventive information exist since end of 1980s but was not so regulate. After flash floods in Mediterranean area, French government reinforced laws for preventive information and memory of natural hazards. The main tools are public meetings, flood marks but also the obligation to inform buyers or tenants of houses in flood risk area. Our case studies have shown that preventive information addresses a theoretical obligation but is not easily transmitted to people. Many documents exist at municipal and regional scales to inform people. These documents describe the risk and give instructions in case of crisis. The assessment of such measures was conducted by analyzing the documents provided but also by their passing on to people that we estimated through interviews with institutional and surveys with populations. The content of the documents is not the same in different territories. Sometimes they are very comprehensive and effective. But sometimes they give not much information and it does not allow to have a clear idea about the risks and precautions in case of crisis information. In Grabels, a third of the 110 respondents had knowledge of one of these documents and more than half of the 188 respondents in Cuxac-d'Aude. We can consider that this kind of document can help to prepare for the crisis. But Figure 4. Extract of IAL (Information for buyer) there's a limit. Even if the people show the information, it’s not sure they will make the right decisions at the The general report of these measures is not totally appropriate time. The other main criticism is that access positive does not suggest that they are effective in to this information depends on the user when the reducing damages and saving lives. Since ten years the information should be communicated. It is often at the preventive measure change to the prevention of crisis inhabitant to search the information, so if person don’t measures that tends to reduce the damage and the deaths. know that a risk can occur it have not information. The case which the information is necessarily transmitted is if an inhabitant sell or rent a house or flat. From now a map must be attached to the sale or lease but limits again. The 3.2.2 Preparness to crisis management, tool of scale of the map and the base map are sometimes illegible safeguard? to understand and not allow the purchaser to obtain reliable information. In addition the document remains Crisis management comes at several spatial scales unclear for example to possible water level during a flood and includes many actors: institutional, emergency (Fig. 4). services but also the weather forecast services, or civil society. Since 2000 the devices, plans have expanded. The meteorological vigilance comes in support crisis management and local officials can rely on public and private companies in addition to emergency services. A new tool has also emerged to help local officials to manage the crisis: the Municipal Safeguard Plan (PCS). These theoretical documents provide instructions to follow in case of crisis. The feedback study to our research, however, show more mixed results. During the events of Lamalou-les-Bains (sept 2014) a small tributary – long about 5 km - caused severe damage and 4 deaths. This kind of streams does not benefit from a hydrological monitoring and nobody can Title of the conference estimate the scale and speed of the flood even crisis management responsibility is only to institutions. While management tools. To Grabels, the Municipal Safeguard collecting is often preferred, our results show that Plan was active and populations was informed by a individual management can be effective especially with telephone warning system. But our interview with local mitigation measures. officials showed the event could have turned a different These preventive measures are regulated by law, way. In fact the electricity was cut by the flood a few but it must also take into account the experience of event time after the alert. In fact, a power outage occurred a by different actors. The experience of an event does not few minutes after the alert. If it had happened a few mean that they will always have good behavior but gives minutes before the results could have been more severe. a little knowledge of risk and risk awareness. Then it is Discussions with populations the next day after flood estimated that the population will be more prepared. To have also shown that they own organized before the alert another side, the event triggers reactions to better manage and call alert firefighters. They don’t have any both collective and individual actions. On the contrary, if knowledge of tools like the Municipal Safeguard Plan in no significant event occurred, so the actors no have risk their town. During the event at Cuxac-d'Aude in 1999, awareness and generally low knowledge to deal with the the Municipal Safeguard Plan did not still exist but the crisis. The tools are then not or poorly developed by the local officials were prevented with the weather forecast institutions and people do not know them. The extent of services. Difficulties of interpretation between the the potential damage never materialized, then, there is no metrological data given to the local officials and the consideration of risk management decisions, or by the information passed on to the populations emerged from people or by the emergency services and crisis. This lack it. This shows the difficulty of transmitting information of event can be felt on the evaluation of the performance but also that despite the tools it is not possible to plan of the preventive information and preparation for crisis everything in a crisis and that there is always an element management in all the studies areas. of hazard. As like mitigation evaluation, those results showed The assessment led on a portion of territory shows a strong influence of the experience of an event in the the difficulty of application of preventive measures and effectiveness of measures. In areas where no "mark" the long way towards effectiveness. In fine, flood risk event occurred in recent decades, then all preparation management is probably not a priority for the measures to crisis management are poorly investigated by stakeholders on exposed territories, even if the institutions and less known by populations. But people's expectations of reducing casualties and damage are behavior are not assessable as shown the many deaths in usually present. Global management do not seem adapted French Riviera in September 2015 in which people died to local specifies and lack of prevention targets make by inappropriate behavior. But this may be due to lack of superficial management. knowledge and awareness of risk.

It’s so difficult to evaluate the effectiveness to this 5 References type of measures because preventive management of 1. Deleau M and Nioche J P (1986). Evaluer les flood risk depends, in part, to the implication of all politiques publiques : méthodes, déontologie, stakeholders. So we can say this tools will be develop for organisation. Rapport pour le Commissariat Général crisis management is more effectiveness. This tools and du Plan, la Documentation Française, Paris, 180 p. the information and awareness of risk allow, in our 2. Pottier N., 1998, L’utilisation des outils juridiques opinion, to reduce number of the deaths. de prévention des risques d’inondation : évaluation des effets sur l’homme et l’occupation des sols dans 4 Preventive management still overpass les plaines alluviales (application à la Saône et à la by structural measures and triggered by Marne, Thèse de Doctorat de l’Ecole Nationale des Ponts et Chaussées, Spécialité Sciences et the events Techniques de l’Environnement, 582 p. After a long period of risk management focused on 3. Defossez S. (2009). Evaluation des mesures de the protection, management tries to globalize with gestion du risque inondation. Application au cas des preventive actions and including all stakeholders. basses plaines de l’Aude, thèse de doctorat, The report of these few researches shows that université Montpellier 3, 462 p. + annexes preventive methods are still in their beginning and it will 4. Heaumé C, (2015). Evolution des perceptions du take time for them to be accepted by local stakeholders risque inondation dans les basses plaines de l’Aude. and anticipated structural measures. The surveys led to Rapport de stage effectué au sein de l’UMR GRED, Cuxac-d'Aude, Grabels, or in other territories as on the Montpellier, 85 p. Atlantic coast after Xynthia, show that expectations of 5. Vinet, F., Boissier L., Defossez S, 2011, « La stakeholders based on structural measures such as dikes. mortalité comme expression de la vulnérabilité Historically, French institutions manage floods with built humaine face aux catastrophes naturelles : deux such as dikes, so it’s necessary to change in mentality. inondations récentes en France (Xynthia, var, 2010) But such measures is also a political display showing », VertigO- la revue électronique en sciences de managing to populations. For their part the people are l'environnement, Volume 11 Numéro 2, [En ligne] also used to protection measures and believe that the URL : http:// vertigo.revues.org/11074 The European Physical Journal Conferences

6. Rey T., Defossez S., Vinet F., Boissier L. (accepted). Cinématique et impacts d’un évènement hydrométéorologique : les inondations du 6-7 octobre 2014, Grabels (France méditerranéenne), Vertigo, 20 p. 7. Leone F. Vinet F., Denain J.C., Bachri S., 2007, Développement d’une méthodologie d’analyse spatiale des destructions consécutives au tsunami du 26 décembre 2004 (Banda Aceh, Indonésie). Premiers résultats pour l’élaboration de futurs scénarios de risque, Géocarrefour, Vol. 82, n°1-2, (numéro spécial risques et territoires), pp. 77-90 8. Lagahe E., Vinet F. (2014) Evaluation de la vulnérabilité des logements face à la submersion marine sur l’île d’Oléron. Projet dans le cadre du projet Risks porté par l’UMR Liens, Université la Rochelle et du PAPI « île d’Oléron, 102 p. 9. Barthélémy F., Lazergues R., Linet M., Pin X., Quevremont P. (2006). Organisation de la prévention des risques naturels dans les services déconcentrés. Rapport de l’IGE 25/054, 20 p. + annexes. 10. Madoré (2004). Les ensembles résidentiels fermés en France, Les Annales de la recherche urbaine, METATTM, n°95, Apprivoiser les catastrophes, p. 99-106. 11. Druon E. (2015). Gestion de crise et vulnérabilité face aux crues torrentielles, étude des facteurs limitant la catastrophe : retour d’expérience sur l’inondation du 6-7 octobre 2014 à Grabels (France), mémoire de master 1 GCRN, 98 12. Veyret Y and Laganier R. (dir). (2013). Atlas des risques en France. Prévenir les catastrophes naturelles et technologiques. Paris, éditions Autrement, collection Atlas/Monde, 96 p. 13. Douvinet J., Defossez S., Anselle A., Denolle A-S. (2011). Les maires face aux plans de prévention du risque inondation (PPRI). L’espace géographique, 1/2001, tome 40, p. 31-49. 14. Caumont V. and Fasquel F. (2012). Risque de submersion marine et marches fonciers et immobiliers sur le littoral du Nord-Pas-de-Calais. Phase 1 : Approche qualitative des marchés et exemples d’adaptations, CETE Nord Picardie, 33 p.