Nevers

About the city and its flooding problem

Within the STARFLOOD project, our three case studies had to represent three different rivers and watersheds. Nevers is a medium-sized city located along the Loire River – largest French river and basin – and is therefore mainly concerned by slow floods. The city of Nevers is the main city of the Nièvre Département in the Bourgogne Région. Its urban area is located at the confluence of three rivers: Loire, Nièvre and Allier. Flooding is the main natural hazard in that territory, and it is not really in competition with other natural or industrial risk.

Nevers
Figure 1: Nevers and the Loire basin

Socio-economic characteristics

 

Nevers Region France

Number of inhabitants

(Insee 2012)

City : 36 700

Agglo.: 68 734

1 642 734 66 317 994
Population density

314 inhabitants/km²

 

General: 52

Urban:

General: 113

Urban:

Population growth (1999-2010)

>20 years

<65 years

(Insee 2009)

City: – 1%

Agglo.: – 0,6%

20%

36%

0,2%

 

23%

19,7%

0,7%

 

24,5%

16,3%

Economic importance

(Insee, 2013)

 

436 companies creations

2% PIB national

9500 Companies creations

 

521 000 companies creations

Fiscal Income average (Insee 2011)

Revenu médian

16 600 18 695 19 218
Unemployment rate (Insee 2014) “Employment zone” : 9,4 (Agglo: 14%) 8,9% 9,7%

 

River and floods characteristics

The Loire is the longest river in France, with a length of 1,012 kilometres. Its catchment basin of 117,054 km2, covers one fifth of France’s land area. Relatively narrow when it leaves the Massif Central, the Loire changes face 450 kilometers from its source, receiving its first large tributary, the Allier. The confluence is called “Bec d’Allier” and constitutes the location site of Nevers. The volume of the river flow doubles here. In Nevers, in the absence of containment, the Loire great flood would rise to a height of 5 to 6 meters above the low water, with a flow of 6000 to 9 000 m3 per second downstream the Bec d’Allier.

Three types of floods can be distinguished (Fournier, 2010). The “oceanic” floods are the most frequent. Resulting from long periods of rainfall from the Atlantic Ocean and generally occur in the cold season. The “cevenol episodes” are due to sudden and violent storms (coming from stormy Mediterranean influences). The flows reach their maximum upstream Loire. Finally, the “mixed” floods correspond to the conjunction of these two events. They most often occur in the spring or fall. The floods in 1846, 1856, 1866 and 1907 are the main “mixed” floods that have marked the last two centuries.

The left bank of the Loire, the most prone to flooding, remained less developed. Small villages only grew at the output of the main bridge crossing the Loire: Sermoise and Challuy. The Nevers city is located on the right bank. The main districts exposed to floods were built after the Second World War, as population growth led to new spatial extensions. The urban physiognomy changed considerably, especially on the outskirts where large sets of collective housing and individual estates conquered the hitherto remained agricultural areas alongside the river (Districts of the “Bords de Loire” and South Nevers). In Total, 12 000 inhabitants are exposed to flood risk.

Nevers2

 

Flood risk and strategies : An exemplary case of mitigation strategy

The management of the Loire River presents historical characteristics, which has always influenced the development of specific local flood risk policy and governance organisations.

On the one hand, the earliness of the containment policy strongly orientated the future action. While the course of the Seine and Rhone Rivers had slightly be constrained until the nineteenth century, the Loire has a long history of massive embankments since the 12th century. First embankments served the interest of transportation and economic development. Until the mid-nineteenth century, the Loire River was indeed the main route on which transited goods from the inland regions to the port of Nantes. Economic use of the river bed was also favored by the embankment: agriculture first, then extraction, electricity production… As a result, 700 km of dikes have been erected along the river !

On the other hand, this onward rush to the maximum containment was periodically questioned. The first « room for water » policy emerged on the Loire in the 19th century with the Comoy Plan. The actual proposal of the river managers to give more room for water echoes the long tradition of the flood management on the river. The dam construction policy that begun in the 1950s to regulate the course of the Seine and Rhône, could not be implemented on the Loire (Villerest and Grangent dams are the only two constructed on the Loire River, along with Naussac on the Allier River, major Loire’s tributary). The local oppositions to the dam construction caused a national conflict, which has lead to the development of a more diversified and integrated policy initiated with the Plan Loire Grandeur Nature.

Finally, at the local level, Nevers took an early interest in the flood management issue compared to the other Loire cities. In the early 2000, it was a pioneer city willing to develop an innovative approach, organising visits in the Netherland and involving in the Interreg program “Freude am Fluss”. Orléans followed in 2010 and recently Tours.

 

Characteristics of flood risk governance in Nevers

The objective of the case study selection was to select a diversity of local governance arrangement. In this regard, Nevers offers an opportunity to analyse a situation where the Loire Basin Water Board (“Etablissement Public Loire” – EPL) and the Water Agency play both a historical and a central role. It is also marked by the involvement of a local municipality (Nevers) and an inter-municipal body, which takes over the action and the view of the EPL.

On the one hand, the basin scale soon appeared as a central one for the definition of the flood policy on the Loire and has had a strong influence on the local policies. The Loire Basin Waterboard (EPL) was created in 1983 and has gradually become a key player in both the field of defense and prevention/mitigation. The Equipe Pluridisciplinaire that emerged in 1996 in the frame of the first Plan Loire questioned its policy and was at the initiative of a policy turn leading to the development of the “Plan Loire Grandeur Nature”. Today, the Water Agency has taken over human and expert resources of the team and is also considered as an influencial player on the definition and implementation of flood management policies at the local level. Even though the role of the EPL and the Water Agency is indirect in Nevers, the policy developed at the basin level was historically and is still today very important in terms of discourses as well as resources (by funding multiple actions, providing expert support, promoting the broadening of actions…).

On the other hand, created in 2003, the local government (“Communauté d’Agglomération de Nevers”) affirms its role in the flood management field through an integrated project called EGRIAN (Etude Globale du Risque Inondation sur l’Agglomération de Nevers). This study specifically addresses the flood risk issue. Its ambition is to address nearly all flood management strategies in a common vision: protection, mitigation, prevention, crisis management. After several years studying the local situation, the local government has come up with a lot of data and expertise. It recently defined its global strategy for the years to come, as well as the measures to be taken, in collaboration with several design, engineering and management consultants. More space should be given to the rivers when waters reach a high level but local development should also keep going on in flood-prone areas. This particular course of action will be particularly addressed during this case study research.

Nevertheless, the question of the compatibility and integration between this local strategy and the legal planning documents that are currently re-designed by the State administration (“Plans de Prévention du Risque d’inondation”, Flood Risk Prevention Plan, ie the binding cartography and rules for flood-prone areas) arises. Tension also occur concerning the protection strategy, which is traditionally under the State’s supervision. Even though the State has given free reins to Nevers agglomeration to study the protection system and develop solutions, the situation becomes more complex when it comes to determining who will fund the works and how much.

Considering the specificities of the Nevers territory, we also have to underline the demographic and urban context, marked by a negative growth and the lack of estate pressure. This particular situation has some consequences on how actors view the risk and how they strive for articulation with other policies.

Nevers3

Research questions

  • What are the conditions to develop and implement a specific local strategy like EGRIAN ?
  • What is the role of a specific Public Basin Organisation ?
  • What can explain the development of mitigation in Nevers ?
  • What are the driving factors of the local involvement?
  • Shock events (2003 and 2008 floods contribute to changes)?
  • State disengagement?
  • Intermunicipal authority rise?