Geological map of Auvergne-Rhône-Alpes.
BRGM Auvergne-Rhône Alpes has two offices in the region, one close to Lyon (Regional Division, in Villeurbanne) and the other near Clermont-Ferrand (Regional Delegation, in Aubière). The two sites work in tandem, pooling resources for regional operations. They employ a staff of fifteen people, including specialists in groundwater and thermal spring water, soil and groundwater pollution, material resources, natural hazards and geothermal issues, and draw on the expertise of BRGM's scientific and technical centre based in Orléans.
One of the most dynamic regions in France
With twelve départements (Ain, Allier, Ardèche, Cantal, Drôme, Isère, Loire, Haute-Loire, Puy-de-Dôme, Rhône, Savoie, Haute-Savoie), the Auvergne-Rhône Alpes region covers some 70,000km² and is the second-ranked French region in terms of GDP and size of population, with almost 8 million inhabitants.
Straddling three hydrographic catchment areas (Adour-Garonne, Loire-Brittany and Rhône-Mediterranean), the region is crossed by the Rhône and Saône rivers, and, to the west, by the upstream section of the Loire river and by the Allier river.
The region has many different facets, with great tourist appeal, and has been extensively developed (hydraulic structures, major infrastructures, etc.). It has also been heavily exploited in terms of resources, for example in major coalfields based in the Auvergne, Loire and Dauphiné areas, and currently for building materials etc. It is the most industrialised region in France, a fact which is reflected by the thirty or so competitiveness clusters and hubs. However, the region also has several mountain ranges (Massif Central, the Alps, the southern part of the Jura Mountains, with 67% of the territory in mountain areas) and a highly developed agricultural sector.
Public and private partners
BRGM has extensive experience of both public and private partnerships. We work on projects to help shape public policy, or for public and private research in response to industrial requirements, as well as training projects aimed at every level of spatial planning and decision-making in the region: State representative bodies and decentralised services (Prefecture, DREAL, etc.), Water Agencies (Rhône-Mediterranean-Corsica Water Agency, Loire-Brittany Water Agency and Adour-Garonne Water Agency), regional and departmental services, as well as local authorities (metropolitan, district and municipal councils, etc.) and water or land management bodies.
BRGM also works on research partnerships with private companies of all sizes to develop methodologies for Research, Development and Innovation aimed at supporting their various fields of activity.
References and projects
Natural hazards: geological risks
Due to the variety of landscapes, the size of the region and the uneven distribution of the population (with major conurbations, a network of smaller towns around the region and dynamic rural areas), the exposure of goods and people to natural hazards is of real concern across the entire region. In view of the many events that have occurred in the past and recent times, geological hazards are a major issue. The main challenges are to improve our understanding of this risk by taking into account the different geological contexts (crystalline, secondary, volcanic, quaternary) and to characterise the socio-economic vulnerability of the different population groups.
Landslide in Sauvat (Cantal, 2014).
© BRGM - Gildas Noury
BRGM's involvement and responses
BRGM's engineers intervene first and foremost as experts during periods of crisis management, working alongside the Prefecture, civil protection agencies, regional authorities (DDT), town halls, and so on. The expertise and responsiveness of the teams from the Auvergne-Rhône Alpes Regional Division were required to respond to the government's urgent needs during recent crises (e.g. rock fall in Culoz in the Ain département, or seismic incident in Le Teil).
BRGM also carries out inventory work, in particular as regards underground cavities, for example under the Butte de Clermont-Ferrand (hill in the centre of the city) in the Puy-de-Dôme département. These cavities are often unused or abandoned, and not all of them have been inventoried, since certain cavities are only found when changes are made on the surface, particularly during construction work.
BRGM also conducts in-depth risk mapping studies concerning the various land movements that occur in the region: landslides, rockfalls, mudslides, cavity collapses, erosion.
The Auvergne-Rhône Alpes region is France's second-ranked mainland region in terms of exposure to seismic risk, with highly variable hazard levels. BRGM supports the DREAL, as well as the regional and local authorities as part of a regional approach to preventing risks linked to earthquakes. BRGM also works with industrial manufacturers to define the level of seismic action to be taken into account to ensure the earthquake resistance of their facilities. Finally, BRGM develops research and innovation projects in order to better understand and prevent risks. For example, research is being conducted to understand and mitigate the effects of major hill-side instabilities in the context of global change, such as in the Arly Gorge and the Upper Guil Valley.
Environment, spatial planning and anthropogenic risks: from urban wastelands to sustainable cities
Today, having the ability to respond to regional challenges in terms of the economy, environment and spatial planning requires having access to comprehensive and accurate knowledge of the soil and subsurface.
The sites and land formerly used for industrial or small-scale activities constitute strategic land reserves and an alternative to the expansion of cities into rural areas, particularly in large regional conurbations (Lyon, Clermont-Ferrand, Grenoble, etc.). However, to exploit these land resources you first need to conduct a diagnosis and characterisation study in order to establish the scale of the clean-up operations (containment, excavation, decontamination works, etc.) required to reassign the land for future uses.
Moreover, the need to develop several underground transport infrastructures (metros, railways, ring roads, etc.) is one of the major challenges facing the region for 2030. The soil and subsurface can also generate risks and disturbances for goods and people and therefore need to be managed through a detailed understanding of the environment. They also need to be anticipated in order to deliver the projects mentioned above and move towards a circular economy (demand for aggregates, recycling of dismantled materials, management of excavated material, etc.).
Brownfield sites in Thiers (Puy-de-Dôme, 2005).
© BRGM - Daniel Rouzaire
BRGM's involvement and responses
In the field of geosciences, BRGM has developed expertise to contribute to the balanced management and controlled use of land and subsurfaces in cities and regions.
BRGM's geoscience expertise has numerous applications in the field of spatial planning and the use of land and the subsurface. As regards underground infrastructures, BRGM can provide planners with a valuable overview through 3D geological representations of the subsurface within the project's perimeter. In order to promote the circular economy, BRGM also evaluates the management of excavated materials (reuse of excavated soil) and secondary raw materials.
As regards potentially polluted sites and land, in 2017, BRGM and the Greater Lyon Metropolitan Council - both pioneers in this respect - completed a flagship Urban Historical Inventories (IHU) operation, which provides an insight into the industrial past on a cadastral (land register) level. On a more general level, a significant update of the inventory of former industrial sites was carried out for the entire Rhône-Alpes region: 1,933 sites were previously known, whereas more than 43,000 sites have now been identified and are gradually being published on the Géorisques portal.
This is a major challenge in such an industrial region, which has thus implemented IDfriches an original initiative, in view of the need to tap into the real-estate potential of the region's wastelands.
In addition to this knowledge of the region's industrial past, BRGM's expertise in the field of polluted sites and soils is being called upon to prioritise the sites identified in terms of their historical or current pollution potential, their origins, the feasibility of remediation and wasteland management.
Energy Transition: using heat from the subsurface
Geothermal energy is one of the possible solutions to help respond to climate change and reduce greenhouse gas emissions. Among the different sources of renewable energy, geothermal technology has high development potential, in order to move towards sustainable cities against the backdrop of increasing urbanisation. Energy can be drawn from the Earth's natural heat, as an alternative to other energy sources.
Geothermal energy has several uses, from providing heating via heat pumps in individual and collective housing or tertiary sector buildings to the production of electricity in locations with high potential. Today, people are generally poorly informed about the geothermal energy sector in terms of implementing the technology and, especially, its potential in different regions. Visit the Géothermies website for more information (in French only).
However, due to the presence of significant hydraulic resources in certain areas, such as Lyon or Grenoble, there has been significant development of geothermal energy in a number of districts over the last few decades. Certain groundwater resources can also be exploited to supply drinking water. Geothermal energy therefore needs to be developed in a controlled manner to reconcile the different uses.
Map of geothermal potential in the former Rhône-Alpes region, published on the website geothermies.fr.
BRGM's involvement and responses
The geothermal potential of a region first needs to be precisely mapped with a view to its operational development. BRGM helps local authorities to diagnose the potential of surface geothermal energy to optimise the sizing of their systems. The development of geothermal energy must take into account detailed knowledge of an area's hydrogeology, aquifers (hydraulic transmissivity, flow rates, temperature, depth, etc.) and subsurface (thermal conductivity, subsurface temperature, etc.) for geothermal probes.
A map of the potential can thus be drawn up from a multi-criteria analysis in order to assess the relevance of developing geothermal solutions (on aquifers or using vertical geothermal probes). The methodology deployed by BRGM can integrate cross-referenced resources and needs for the region concerned by comparing the theoretical density of extractable energy per grid cell with the current (and even future) energy consumption.
These projects also need to take into account key potential issues concerning the groundwater resources (demarcation of safeguard zones for drinking water, warming of the water resources) or the prohibition of drilling (such as around the CERN ring, etc.).
BRGM develops projects with local authorities to manage the developments and ensure the facilities operate properly and profitably. For example, since 2019, BRGM has been developing an Observatory to monitor the warming of the Lyon water table on behalf of the Greater Lyon Municipal Council, in conjunction with its partners CEREMA Centre Est, DREAL AURA, ADEME AURA). It is a thermal and hydrodynamic observatory of the water table, which aims to distinguish areas where the development of geothermal installations is no longer recommended (due to an impact which has already been observed) from those where development is still possible. The aim is to control the warming of the underground water while also establishing a strategy for exploiting the resource, in order to maintain the geothermal potential of the aquifer and protect the water resource over the long term.
Natural Resources: groundwater
In the Rhône-Mediterranean and Corsica basins, 80% of the volume of raw water intended for drinking water is drawn from groundwater. In addition to being subject to strong anthropogenic pressure, linked to the development of urbanisation and industrial and agricultural activities, the groundwater resources used for drinking water may also be affected by "historical" pollution, a legacy of former industrial or military activity.
There are several major challenges linked to the sustainable management of these essential resources, such as identifying and understanding the hydrogeological phenomena at work with respect to the various sources of pollution, monitoring the quality of water masses, understanding the conditions that favour the recharging of aquifers and identifying new resources.
Pertes de la Valserine: the Valserine river passes under a limestone plateau and flows out into the Rhône a few kilometres further on (Bellegarde, Ain, 2007).
© BRGM - François Michel
BRGM's involvement and responses
In relation to the region's industrial background, various initiatives have been undertaken to develop methods for assessing the impact of industrial activities on groundwater quality. This work provides the relevant technical data required to assess the quality of the groundwater masses with regard to the many different impacts due to industry in the vicinity of the region's large cities. These studies are mainly carried out in conjunction with the region's conurbation authorities and with the support of the Rhone-Mediterranean-Corsica Water Agency.
BRGM provides its expertise to both managers and users of water, such as water distribution boards, management bodies in sub-catchment areas, in order to improve their understanding of the hydrogeological behaviour of groundwater masses, the relationships between groundwater/rivers/wetlands and how the resource is likely to evolve in different climate change scenarios. This may involve the development of 3D numerical models of how the aquifers work, thus providing decision-making support tools for managers.
BRGM also works on innovative research subjects, such as tools to support decision-making by mapping the potential rainwater infiltration sites that are most beneficial for the groundwater, in line with the objectives of the Rhône-Mediterranean-Corsica Water Management Master Plan (SDAGE) concerning rainwater management and the fight against soil sealing. The recently developed methodology draws on a large amount of information (occupation/use of land, intrinsic soil and subsurface parameters, etc.) available for the entire area of the former Rhône-Alpes region (the boundaries and name changed in 2016).
During the deployment of the Nitrates Directive, and notably within the framework of changes to the current zoning plan, many questions arose concerning the fact that certain criteria were not accurately represented in the network for monitoring the water quality of the "Limagne" groundwater mass (in Auvergne), and the consequences of this in terms of categorising the municipalities concerned by this mass of water. The study (carried out from 2016 to 2019, in partnership with the Loire-Brittany Water Agency) made it possible to appreciate the degree of representativeness and to propose measures to be taken jointly with the government departments and representatives of the agricultural profession.
- Identifying and characterising new aquifers that could supply drinking water to small communities - definition of safeguard zones
- Identifying and characterising potential new mineral water resources, with a view to developing this economic sector
Natural Resources: geological materials
The region's geological resources (sand, aggregates, etc.) are today in great demand to support economic development in Auvergne-Rhône Alpes. Updating the knowledge base and identifying new material resources - especially strategic deposits - is a priority.
Ultra-pure kaolin used for the manufacture of ceramics, Echassières quarry (Allier, October 2018).
© BRGM - Isabelle Duhamel Achin
BRGM's involvement and responses
In the field of geological materials, BRGM made a geological inventory (in order to meet the deliverables required by the regional quarry plans), which resulted in the development of a regional map of primary raw materials, drawing on pre-existing work. BRGM pursued its work on this subject by identifying potential deposits in the region.
BRGM also works with mining companies to improve local geological knowledge and identify new resource sites in France and even Europe.
Partners can possibly benefit from the Extra&Co scheme which is aimed at micro-enterprises, SMEs and middle-market companies in the "Extractive and Primary Processing Industry" sector, and financed by the French government's Investissements d'Avenir (Investing for the Future) programme. The primary purpose of Extra&Co is to support companies' R&D and Innovation projects, by providing a range of services with access to cutting-edge technological skills and resources ("platforms"), covering subsurface exploration, resource extraction & exploitation and the management of environmental impacts).
Within this context, BRGM is currently heading up an R&D project with a quarry company to develop geophysical methods for identifying a specific material in the region.
In order to improve its geological knowledge base, the foundation on which all BRGM projects are built, an initial airborne geophysical survey (electromagnetism, magnetism and gamma-spectrometry) will be carried out in the Auvergne area during 2020. The survey will make it possible to assess the value of this powerful method's contribution in terms of 3D imaging of the subsurface and of how it can be harnessed to meet regional needs.
In terms of publishing geological and, on a broader level, geoscientific information, BRGM is involved in an innovative project with a company based in the Auvergne-Rhône-Alpes region, aimed at disseminating its data to the largest possible audience in a more fun and attractive way, through the development of hiking-trail applications for smartphones.