Nouvelle Aquitaine

The BRGM has agencies in all the administrative regions of mainland and overseas France, working to meet the needs of its regional partners and help them deal with specific local challenges. This article describes the activities undertaken by the BRGM's regional division for Nouvelle-Aquitaine.
Geological map of Nouvelle Aquitaine

Geological map of Nouvelle Aquitaine.

© BRGM

The BRGM’s Nouvelle Aquitaine division employs 31 people at two different sites, the regional head office in Pessac and the regional delegation in Poitiers. The two teams work together, networking to provide mutual support as and when required.

France’s largest administrative region

The twelve départements making up France’s largest administrative region, centred on Bordeaux, are very diverse, extending from Bressuire to Oloron-Sainte-Marie, from Biarritz to Guéret and from the Ile de Ré to Tulle, and taking in Angoulême and Poitiers.

Nouvelle-Aquitaine, France’s main agricultural and wine-growing region, has a population of almost 6 million, 700 km of coastline, 6 university centres and cutting-edge R&D activities with a priority focus on renewable energy development.

The region’s economic and spatial planning objectives are set out in two regional plans to which the BRGM is contributing its expertise in its core areas of competence: the SRDEII plan for economic development, innovation and internationalisation and the SRADDET plan for spatial planning, sustainable development and equality between different areas. 

Working with public and private partners 

The BRGM has gained wide experience of working with partners on projects to support public policy development, as well as on research and training at every level in regional policy-making and spatial planning. These partners include regional and département councils, intermunicipal bodies, municipalities, water supply associations, regional agencies (water, public health, energy), government departments, public institutions (Ifremer, Fredon, etc.), and associations (e.g. Association of French Mayors).

The BRGM also works with private companies of every size, on methodology development and RDI (Research, Development and Innovation) to support their fields of activity.

Practical information

Aerial view of the Centre beach, Bidart

Natural risks - protecting the coastline

BRGM runs the Aquitaine Coastal Observatory, which facilitates networking between experts to support management and protection of the Aquitaine coast against erosion and coastal flooding.

The challenges

The Atlantic coast is attracting more and more new residents and tourists (+0.6% per year). But with increasing urbanisation, its fragile coastal heritage is already experiencing the tangible and predictable consequences of climate change (storm surges, sea level rise, severe erosion), which are raising serious risks for its population, infrastructure and the environment.

A rockfall along the Miramar cliff near Biarritz

A rockfall along the Miramar cliff near Biarritz (SW France, 2010).

© Observatoire de la côte aquitaine - M. Le Collen

BRGM involvement and responses 

The Aquitaine Coastal Observatory is run by two operators, the BRGM and the ONF, and funded by the EU (ERDF), the French State, the Nouvelle-Aquitaine Region, the Gironde, Landes and Pyrénées-Atlantiques départements and the Inter-municipal agency for the Arcachon  Basin (SIBA).

It facilitates networking between experts to support management and protection of the Aquitaine coast against erosion and coastal flooding.

The Aquitaine Coastal Observatory has several key roles:

  • furthering knowledge, in particular through a unique measurement and observation network;
  • expert studies to provide know-how and decision support for elected representatives and policy-makers;
  • communication, by providing reliable online data for the general public and managers.

Examples of research and studies on coastal risk prevention 

  • Coastal erosion arising with climate change (with the Adour-Garonne water agency).
  • Adaptation to climate change in Aquitaine and strategies to control coastal erosion.
  • Effects of climate change on coastal marshlands (with the Conservatoire du Littoral).
  • Revising coastal risk prevention plans (e.g. with the DDTM for the Gironde département).
  • Study on the dynamics of sediment flows and stocks. Example: the MAREA  project, with the  Basque Country Urban Community (CAPB).
Marl-limestone alternating, Pyrénées-Atlantiques

Natural risks: ground movements

The BRGM carries out inventories and geotechnical diagnoses of subterranean cavities. It also works on natural ground instability risks.

The challenges

Much of the subsoil underlying inland towns and infrastructure in Nouvelle Aquitaine is riddled with thousands of subterranean cavities, especially in the Gironde, Charente, Vienne and Haute-Vienne départements. These cavities include former limestone and slate quarries used to extract building stone or soil amendments, vintners’ cellars, cave dwellings, ornamented caves, tunnels and refuges.

Most are disused or abandoned and not all have been identified: some only come to light if a disturbance occurs on the surface, such as subsidence (forming a swallet) or a cavity collapse. Identifying these cavities is essential to ensure the safety of people and property on the surface.

Other sectors are affected by cliff falls or flooding due to water table rise in karstic cavities after heavy and prolonged rainfall.

Sinkhole formed by the collapse of a cavity in the Allasac slate quarry

Sinkhole formed by the collapse of a cavity in the Allasac slate quarry (Central France, 2012).

© BRGM - Florence Auclaire

BRGM involvement and responses

The BRGM carries out inventories and geotechnical diagnoses of subterranean cavities, for government departments and others in charge of natural risks or road infrastructure.

On completion of its studies, the BRGM produces maps on which the perimeter of subterranean cavities (which sometimes form a labyrinth extending over several kilometres) is superimposed over the relevant cadastral land parcels and surface infrastructure, to show where they overlap and to detect any sectors where cavity collapses are liable to occur.

These studies are also presented to municipal agents and to the population after the project is completed.

The BRGM also works on natural ground instability risks, for example in mountain areas or collapse-prone sectors in the Dordogne.

The Jonquilles River, Corrèze

Natural resources: support for sustainable groundwater management

Demographic growth, tourist use and agricultural irrigation are factors in conflicts over groundwater use, reinforced by the context of climate change. BRGM assists regional players in their water strategy.

The challenges

In Nouvelle-Aquitaine, intensive irrigation and a growing population, which increases fourfold in the summer tourist season, are factors that generate use conflicts over groundwater resources that supply drinking water for human consumption.  In today's climate emergency context, tensions over water resources can only worsen. 

3D representation of the 15 aquifers covered by the MONA model for northern Aquitaine

3D representation of the 15 aquifers covered by the MONA model for northern Aquitaine.

© BRGM

BRGM involvement and responses

The BRGM is assisting the region and its water agencies with their strategy for water resources: Regional agreement comprising seven modules on groundwater issues, including in particular the development of a regional hydrogeological model, a GIS for groundwater and a web portal.

The BRGM is providing its expertise to water users and managers such as agricultural federations and cooperatives, management bodies and basin agencies. 

It is also working on a wide variety of research topics that include development of 3D digital models of aquifer functioning across the entire region, the effects on water resources of different climate change scenarios and ensuring drinking water supplies for livestock while protecting wetlands. 

And also:

  • Training for secondary school teachers in Earth and Life Sciences (with the regional academic authority);
  • Prospecting for alternative resources in the Médoc area;
  • In the Charente département, studies on water management in the summer (agricultural context);
  • Information systems for groundwater management (ISGM) (SIGES Poitou-Charentes - SIGES Aquitaine).
A "tentative diagram" of different geothermal heat sources

Geothermal energy: supporting the energy transition

The energy transition is one of the region’s main policy areas. Geothermal energy is one of the components of the energy mix considered for new buildings in the region.

The challenges

Nouvelle-Aquitaine has significant potential for low-temperature geothermal energy, with exemplary geothermal facilities that have been supplying heat, in some cases since the 1980s, for residential neighbourhoods, commercial centres and airports in Bordeaux, Pessac, Mont-de-Marsan, Dax / Saint-Paul-lès-Dax or Mérignac. Other deep boreholes are in use for more targeted purposes (swimming pools, fish farms). Recent facilities are supplying heat and cold for businesses (Crédit Agricole head offices in Poitiers and La Rochelle), public buildings (e.g. hospitals in Poitiers and Rochefort, social security offices in Bayonne, schools and care homes for the elderly).

Atlas of geothermal potential in Nouvelle-Aquitaine

Atlas of geothermal potential in Nouvelle-Aquitaine published on the website geothermies.fr.

© BRGM

BRGM involvement and responses

To fulfil its key roles in geothermal energy promotion, training and feasibility analyses for local government and industries, the BRGM organises geothermal energy workshops with the ADEME in Pessac and Poitiers, facilitated by two engineers. For local-scale projects, it provides scientific and technical assistance for pre-feasibility studies.

In 2011, the BRGM began work on an atlas of geothermal potential in the former Aquitaine region. Full coverage of the Poitou-Charentes and Limousin was completed in 2018.

Example on the local scale: a geothermal energy mini masterplan for the SYBARVAL joint management agency

SYBARVAL (the agency responsible for reviewing and monitoring planning consistency in the Arcachon Basin–Val de L’Eyre area) had set out ambitious goals for halving energy consumption and trebling renewable energy production. Geothermal energy can potentially cover the majority of heating needs in the residential and tertiary sector across the whole area. The study undertaken aims to assess the availability of resources in the light of current and projected needs, in order to provide the SYBARVAL with user-friendly planning tools. The toolkit will in particular include detailed maps of the potential coverage of heating needs by geothermal energy. 

This approach also features an innovative component that will characterise possibilities for converting a large number of former petroleum prospecting boreholes to capture underground heat.

Part of an eroded cliff on the Basque coast, Pyrénées Atlantiques

Geology: mapping applications and user support

BRGM produces maps and geological data with applications in the fields of mineral resources, water and natural risks.

The challenges

Compiling geological data from the three former administrative regions into a single set requires a specific effort to homogenise data across the previous boundaries, in particular for mineral resources and quarries, knowledge of natural risks and aquifers.

A geology field assignment in the Pyrenees

A geology field assignment in the Pyrenees in collaboration with academic partners (Pyrenees, 2015).

© BRGM

BRGM involvement and responses

The BRGM is producing a geological map to the scale of 1:250 000 (relevant for all the different players), with an emphasis on its educational value as a means of highlighting connections with the natural heritage and biodiversity, for example. 

Projects now in the pipeline include production of a homogeneous synthesis of the different quarry plans and publications in the BRGM guidebooks on Geological curiosities collections to promote knowledge of the geological heritage among residents and visitors.

And also:

  • Regional quarry plans, for the DREAL;
  • Involvement of regional BRGM divisions in components of the RGF Pyrenees module.
Photographic report of the Aquitaine Coast Observatory, Urrugne

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