3.1 Study area and past flood disasters
The PACA region in France is characterized by steep slopes and deep valleys, the coastal plains are surrounded by the Cévennes mountain range in the North West and the Alps in the East. Summer drought and intense Autumn rainfall are typical features of the climate (Petrucci et al., 2019). Rainfall is concentrated over the period September–December (50% of annual total). Winter is drier with cold, continental winds. Flash floods are common in the region (e.g. Vinet, 2008; Vinet et al., 2012; Heinzlef et al., 2019) with an important number of deadly historical events taking place since the creation of the CatNat national solidarity scheme in 1982. Some notable extreme flooding events that have provoked loss of life as well as significant material costs include the Vaison-la-Romaine floods (09/1992), the Draguignan floods (06/2010) and the most recent Côte d’Azur floods (10/2015). The region has also faced smaller flood events such as the Var and Alpes-Maritimes floods (11/2011; 11-12/2019) and the Nice floods (11/1994; 12/2005). According to Heinzlef et al. (2019), due to these issues, in the last 10 years, several PACA municipalities (e.g. Avignon) attempted to emphasize resilience in their urban planning.
3.2 The October 2015 Côte d'Azur disaster
According to the official document of the Préfet (Regional authority) des Alpes-Maritimes report (2016), on Saturday the 3rd of October 2015 between 20:00 and 21:45 an exceptional rainfall event took place between Mandelieu-la-Napoule and Nice (for official rainfall maps see Météo-France[1]). This highly intense event, with approximately 200 mm of water in two hours is comparable to the 1966 catastrophic event that took place in the same region. According to Carrega (2016), these values correspond to a larger than a 100-year storm. More specifically, the Cannes Meteorological station recorded 175 mm of rainfall in two hours, which is approximately 80 mm more than the 100-year event (94,6 mm). This exceptional rainfall caused a substantial increase in river discharge (>250 m3/s, larger than the 100-year event as well), in the Argentière and the Brague rivers thereby reaching the levels of the 2010 flash flood that took place in the Var, also in southern France (Vinet et al., 2012). In addition, due to regionally steep slopes covered by Mediterranean vegetation, large, woody debris was swept into water courses, which dammed the main channels and caused water to be diverted onto floodplains. The Prefect of Alpes-Maritimes Region report (2016) declared that 20 people lost their lives during the event and that 1200 people were in need of immediate disaster relief measures.
3.3 PACA flood risk governance deficiencies
In the years following the October 2015 disaster, a number of reports were published (e.g. The Prefect of Alpes-Maritimes Region report, 2016; ARTELIA, 2017; CEREMA, 2019) that listed a number of pre-existing issues that might have led to the disaster such as a) inadequate land-use planning, b) inadequate prevention plans, c) inadequate warning systems in place, d) inadequate maximum threshold for emergency calls (only 20 calls simultaneously), e) lack of appropriate rain forecast modelling, f) lack of citizens’ operational knowledge after an alert is initiated, and g) lack of road network mapping. These issues seem to be the same as the issues in past local disasters (listed in Section 3.1). In the following sub-sections (3.3.1 -3.3.3) we will briefly analyse all aspects of FRG in PACA (which follows the French governance system summarized in Figure 1) to observe, in detail, the pitfalls leading to repeated disasters.
3.3.1 Risk prevention
The current French FRG system is based on prevention (e.g. Kaufmann and Wiering, 2017; Fournier et al., 2018). The main goal is to reduce the exposure by the use of the legal instruments mentioned in Section 2, such as the PPRi and the PAPI, and therefore the enforceability remains high. Nevertheless, it seems that these instruments had been significantly out-dated when the 2015 event took place (e.g. in Cannes the last PPRi was approved in 2003) and local population wasn’t aware of this issue. This was also observed during the June 2010 Draguignan disaster, where 22% of residential buildings and approximately one in three employees were commuting into a flood risk zone for their work (INSEE, 2018).
Before 2010 flooding was considered to be a controllable natural phenomenon and the government was putting in place an important number of flood defences as part of those controls (Larrue et al., 2016; Kaufmann and Wiering, 2017). This trend is now changing, and the effectiveness of structural measures is recently questioned (Kaufmann and Wiering, 2017; Kron et al., 2019). During the October 2015 Côte d'Azur disaster, the artificial protection dikes were largely ineffective due to the severity of the phenomenon (with river discharges being larger than the 100-year event), while some dikes also trapped the large debris, thereby blocking the flow and worsening the situation (The Prefect of Alpes-Maritimes Region report, 2016). A similar phenomenon was observed in the September 1992 Vaison-la-Romaine disaster. According to Ballais and Segura (1995), the protection dikes and embankments which were put in place during the second world war to straighten the channel in the valley and provide space for construction, intensified runoff turbulence, and transported boulders and woody debris that blocked bridges and promoted damage downstream.
Moreover, flood mitigation measures such as retention ponds and wetland restoration are considered a viable option for flood management because they not only improve resilience directly by improving runoff management, but also indirectly through improving the legitimacy of the PAPI project, thereby illustrating the advantages of land-based flood control (Barraqué and Moatty, 2020). After the October 2015 event, PACA inhabitants were promised the construction of new retention ponds as well as the reinforcing of mitigation measures. In 2001, some years after the Vaison-la-Romaine and other flood disasters around France, the Assemblée Nationale (2001) published a document suggesting measures for regions facing repetitive flood disasters, such as in the PACA region. They underlined that the natural retention capacity has decreased due to the disappearance of wetlands which were often replaced by intensive agriculture, heavy infrastructure, and the extension of waterproof surfaces.
Another important prevention tool is the municipal information document on major risks (Document d’information communal sur les risques majeurs - DICRIM) which is designed to inform the local population of each municipality about existing risks and the different ways to protect against those risks. In short, the mayor is charged with informing the citizens exposed to major risks, and after that the government indicates the adequate protection measures and municipality safety plans, or Plans Communaux de Sauvegarde (PCS), in order to respond to a major disaster, if it occurs. The Prefect of Alpes-Maritimes Region report (2016) analysed 10 DICRIMs out of the 14 municipalities that suffered from the October 2015 PACA disaster (four did not have an available DICRIM). In three of these DICRIMs the mapping was inappropriate, with several locations missing per map and in all DICRIMs there was a lack of explanation of the particular characteristics of flash floods while the vulnerable locations were not clearly identified.
3.3.2 Emergency management
According to Vinet et al. (2012), when a natural disaster strikes it is most often the elderly that face difficulties dealing with early warnings or evacuation orders. During the October 2015 event, there was lack of information on flood risk as well as lack of preparedness to face catastrophic flooding, and no appropriate alert system in place. According to the Préfet des Alpes-Maritimes report (2016), the alert level, which functions with a colour coding (yellow-low risk, orange-medium risk and red-high risk), was misused. Météo-France triggered orange alerts on a regular basis since the creation of the system, which has the effect of normalising and trivialising the severity of the orange alert level. Furthermore, after observing the rainfall and discharge during the October 2015 event, the red alert signal should have been triggered which was not the case (the alert remained orange). Carrega (2016) underlines that inaccurate meteorological (rainfall) models forecasted only about 25% of the precipitation that occurred during the event thereby causing more confusion to the alert system. In addition, civilians apparently did not have sufficient knowledge of the alert protocol, which would allow an understanding of the alert messages, with many being confused on the colour coding. The French alert system (Flood vigilance - Vigicrues) also faced criticism during the June 2010 Draguignan disaster since the three main overflowing rivers causing significant damage to local communities were not monitored by the Vigicrues system (Sénat report, 2012).
Another important aspect that needs to be investigated relates to the emergency services training for flooding. According to Sénat (2012), the Prefect of Alpes-Maritimes Region (2016) and the CEREMA (2019) reports, which discuss the events presented in this paper (e.g. June 2010 Draguignan, October 2015 Côte d'Azur, November-December 2019 PACA), noticed that, despite the important number of fire-fighters involved and the declared emergency interventions (e.g. 1500 interventions and 600 fire-fighters involved in 2015), there were a lack of robust protocols for flood disasters. Apparently, local population, government and emergency services downplay flood risk (considering it medium risk) if compared to forest-fire risk, which leads to PCSs focused on the risk of wildfire rather than flooding. Consequently, the report from the Ministry of Environment (Ministère de l’environnement, de l’énergie et de la mer, 2016) suggested that, after the October 2015 event, a flood information and action week should take place, where all stakeholders could be involved (e.g. Météo-France, government, fire-fighters) and where all past events could be demonstrated. This type of yearly workshop already exists in wildfire and earthquake hazard prone areas in France, but not yet for floods.
3.3.3 Disaster recovery
Recovery in the French system is mainly based on insurance. Numerous authors have already pointed out some of the pitfalls of the current French flood insurance system and suggested a shift towards a new PPP mechanism offering more flexibility (e.g. Larrue et al., 2016; Kaufmann and Wiering, 2017; Fournier et al, 2018; Hudson et al., 2018; Kron et al., 2019; Barraqué and Moatty, 2020). The French solidarity insurance system, although very inclusive with more than 95 % penetration seems to have played, unintendedly, a negative role in resilience, by blocking the possibility of a BBB culture (Barraqué and Moatty, 2020). In addition, according to Barraqué and Moatty (2020), the refunds received by the disaster victims cover the actual damages incurred, but numerous aspects, such as outdoor housing damages or non-monetary aspects (e.g. emotional impact), are not taken into account. According to the report from the Ministry of Environment (Ministère de la transition écologique, 2019), insurance companies refund on average 500 million euros for flood disasters, and the October 2015 event alone generated approximately 650 million euros of damage, which signals a heavy financial blow to insurance mechanism. Furthermore, approximately 60,000 insurance claims were registered with 60% relating to housing damage, 30% to car and 10% to business. The extended impacts of this event led to a very high number of insurance claims, underlining the necessity for crisis units deployed in the field to deal directly with the claims as well as the increase in phone assistance capacity and the acceleration of refunds from the insurance companies.
3.4 Persisting flood disasters after 2015
After the October 2015 Côte d'Azur disaster discussed above, a number of preventive measures were put in place by the government (Table 1).
Despite persistent government efforts, the impacts of flood events in the region do not appear to have lessened over time, and heavy rainfall events continue to cause loss of life and to induce important material and immaterial damages at the same time. According to Météo-France[2], since the October 2015 event, 17 notable rainfall events took place in PACA up to January 2020 leading to 14 flood victims in total. Two recent events on 22-24/11/2019 and 01/12/2019 account for 11 of the victims and have also caused serious material damage. According to the French Insurance Federation (Fédération Française d’ Assurance - FFA)[3], the costs of these two disasters total 390 million euros, while 57,000 insurance claims were registered (54% relating to housing damage, 12% to car and 34% to business).
Identical losses can be observed in the Riou de l’Argentière watershed. The stream that has burst its banks during the 2015 event did so again in 2019 causing damage to the same locations, while several protection dikes around the flooded area failed during these events, triggering local inhabitant protests in Mandelieu-la-Napoule as illustrated by the France 3 news channel on 01/12/2019[4] and on 06/09/2020[5]. In addition, the retention ponds promised after the 2015 disaster were still missing in various locations and are now estimated to start functioning in 2023 (see France-Digues on 09/12/2019[6]). Bokhove et al. (2019) conducted several workshops with local citizens in 2018 at the River Brague in Biot, and they illustrate that residents asked for more flood retention measures. Furthermore, the CEREMA report (2019) illustrates that only 2% of the total population use the #MyPredict app which alerts population against flooding, underlining the need for better communication on the side of flood governance.
More recently, in October 2020 (exactly five years after the October 2015 disaster) another major event took place. According to the FFA and CCR (2020) press release, after the 2020 catastrophic flooding event, 14,000 insurance claims were registered with a total cost of 210 million euros, again mostly damaging housing (72%) compared to business (25%) and car damages (3%), and nine people lost their lives. The historical disaster analysis of the PACA region underlines the need for new policies to be put in place. As we observe in Le Moniteur (2020), the Architectural association of Côte d’Azur (Syndicat des architectes de la Côte d’Azur) are suggesting a new way of thinking linked to flooding risk starting with not rebuilding in the same locations again (or in the same manner) but rather adopt a BBB logic by strictly avoiding the areas identified as potentially flooded in the PPRi[7].