BRGM has offices in every region of mainland France and in the French Overseas Territories, in order to meet the needs of its regional partners and help them deal with specific local challenges. Presentation of the activities carried out by BRGM's Regional Division for Brittany.
Geological map of Brittany

Geological map of Brittany.


BRGM's Regional Division for Brittany is based on the northern side of the city of  Rennes, on the Beaulieu Atalante site. The team is made up of eight people, specialised in hydrogeology, regional geology, coastline geology, and geochemistry.

France's leading region in terms of agriculture and fishing

Brittany, in the central part of the Armorican Massif, is a peninsula that covers a surface area of 27,209km2, with an extraordinary coastline of 2,730km.

The region has two major cities, Rennes and Brest, and comprises four départements (Côte d'Armor, Finistère, Ille-et-Vilaine and Morbihan) with a total population of 3.27 million inhabitants (2014).

Despite a steady decline in recent decades, Brittany remains France's leading region in terms of agricultural production and fisheries. The region has experienced an increase in industrial employment, particularly in the agri-food, automotive, ship-building, electronics and telecommunications sectors. Tourism represents a major part of the region's economic activity (it is ranked as France's 4th most popular destination for domestic tourists and 5th in terms of tourists from abroad). The tertiary sector (retail trade and services) accounts for 74% of jobs, and the region has a dense fabric of small and medium-sized enterprises, with an unemployment rate (8.6%) below the national average (9.8%).

The region officially established a set of objectives in 2013 through "Le Pacte d'avenir pour la Bretagne" (Pact for the future of Brittany). These are now set out in the "Regional Master Plan for Economic Development, Innovation and Internationalisation" (SRDEII) and the "Regional Master Plan for Spatial Planning, Sustainable Development and Territorial Equality" (SRADDET), to which BRGM contributes its expertise in its core areas of specialisation.

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 (DREAL, DDTM, ARS, Prefectures), local authorities (the Region: development of the Brittany Water Plan, recently-acquired responsibility for managing and coordinating the Water Policy; the GIS CRESEB; the major water management syndicates: Morbihan Water Syndicate, Rennes Catchment Basin Water Syndicate; major cities: Rennes, Brest, etc.), Agencies (Loire-Brittany Water Agency/AELB, Environment and Energy Management Agency/ADEME), universities (Rennes 1, UBO, UBL).

BRGM also occasionally works with private companies to develop methodologies for Research, Development and Innovation aimed at supporting their various fields of activity.

Practical information

The island of Bréhat, Brittany

Natural resources: groundwater protection and rehabilitation

Some 80% of the Brittany Regional Division's activity concerns projects linked to studying and protecting groundwater.

The challenges

The Brittany region concentrates a great deal of French food production, which has led to significant problems in terms of water being contaminated by nitrates and phytosanitary products: the water in rivers and coastal bays (development of green algae), but also groundwater, whose quality has been greatly affected.

Since 1990, the Region has undertaken measures to restore water quality (Pure Water Programme, then GP5 (Grand Project 5)), which have resulted in a significant drop in nitrate concentrations over the last fifteen years. Since 2014, the Brittany Conference on Water and Aquatic Environments (150 stakeholders in water management and spatial planning), has been contributing to the Brittany Water Plan which aims to achieve a high level of quality for 69% of its water masses by 2021 (European Water Framework Directive).

With new areas of responsibility having been assigned to inter-municipal councils (French MAPTAM and GEMAPI) the Region decided to ensure the coherence and continuity of the measures implemented. In May 2017, the government placed the Regional Council in charge of coordinating the measures taken for the region in terms of managing water and the aquatic environment for the catchment basin.

Water sampling for chemical and isotope analysis

Water sampling for chemical and isotope analysis (2008).


BRGM's involvement and responses

Some 80% of the Brittany Regional Division's activity concerns projects linked to studying and protecting groundwater. The Division's team of experienced hydrogeologists (in collaboration with BRGM's Scientific and Technical Centre) deals with all types of issues concerning groundwater: monitoring groundwater levels and recharge rates, assessing and locating available resources, assessing the state of the groundwater and searching for the causes of contamination, assessing exchanges between groundwater and rivers, estimating water replenishment times, providing decision-making tools, managing water in urban areas, monitoring saltwater intrusion in coastal aquifers, etc.

BRGM is currently working on several projects concerning groundwater:

  • A study of the 100 most productive deep and semi-deep boreholes in Brittany in order to identify the geological, structural and hydrogeological environments that are most favourable for water production. The identification of sectors with high potential, with a view to protecting strategic areas for the production of drinking water in the future.
  • The impact of a drinking water catchment area on a watercourse's flow and on the related wetlands (Morbihan).
  • Coastal aquifer vulnerability to saltwater intrusion.
  • An assessment of the permeability of bedrock aquifers based on piezometric data.
  • Mapping of areas with poor rainwater infiltration and mapping of aquifer levels in the greater Rennes area.
  • The design of educational and communication tools for the site devoted to the management of groundwater in Brittany (SIGES Brittany).
  • An exhaustive review of groundwater extraction and uses covered by the scope of the Argoat-Trégor-Goëlo SAGE (water management plan),
  • Assessment of the impact of the reforestation of protective zones around drinking water catchment areas in terms of improving water quality.

And also:

  • Management of the network that monitors groundwater levels in Brittany (52 points monitored).
  • Expert audits in the field of hydrogeology.
  • Participation in drawing up the regional water strategy, in collaboration with various organisations: CRESEB (Brittany Centre for water resources and scientific expertise), Technical and Scientific Committees, OSUR (Rennes Sciences of the Universe Observatory), Brittany Environment Public Interest Group (GeoBretagne), COREB (Council of Research organisations in Brittany), Eco-Origin cluster, Espace des Sciences de Rennes (Rennes Science Area).
  • Contribution to the Regional Health-Environment Plan no. 3, the Brittany Water Plan and studies for the Green Algae Plan 2.

The challenges

The Brittany region is greatly influenced by its proximity with the sea. Its 2,730 kilometres of coastline offer a wide variety of landscapes, and geological and geomorphological outcrops, which are all interlinked. However, the coast is subject to several natural hazards: within a very short distance, erosion and a retreating coastline affect both the cliffs and beaches, and may be even be accompanied by sedimentation. Recent storms, and in particular Johanna in 2008, had a significant impact on the Brittany coasts and made a strong impression on the region's inhabitants.

The granite chaos of Ploumanac'h in Perros-Guirec in the Côtes-d'Armor

The granite chaos of Ploumanac'h in Perros-Guirec in the Côtes-d'Armor (France, 2005).

© Pierrick Graviou

BRGM's involvement and responses

Government agencies, notably the DREAL and the DDTMs, have implemented various measures to improve knowledge, prevent risks and adapt to changes in the face of global warming.

The North Atlantic - Western Channel Sea Basin Strategy Document (French DSF) is therefore being drawn up and includes a section on the possibility of setting up a Coastal Observatory in Brittany.

Since 2012, BRGM has been helping to improve the knowledge base and finalised the Atlas of coastal hazards in 2015, for the départements of Ille-et-Vilaine, Côtes-d'Armor and Finistère. In order to have a comprehensive, consistent region-wide overview, the same work is being done for the Morbihan département.

BRGM is involved in the Brittany strategic sea and coastline network and is also part of the steering committee of the OSIRISC (integrated observatory for coastal erosion-submersion risks) research project, led by the University of Western Brittany.

Diagram of BRGM’s experimental geothermal energy platform in Orléans

Energy: the development of geothermal energy

For several years now, the Brittany regional council has been trying to promote a variety of renewable energy sources. Geothermal energy is a promising alternative energy source with great potential.

The challenges

Implementing the principles of ecological and energy transition for green growth has been included in the French government's strategy for Brittany.

Since 2006, geothermal energy (a clean, renewable energy), has been developed significantly in the region. Between 2007 and 2010, nearly 1,400 geothermal boreholes were drilled in Brittany each year. Most of these installations concern very low-enthalpy geothermal systems (with heat pumps) that do not tap into groundwater.

For several years now, the Brittany regional council has been trying to promote a variety of renewable energy sources (marine, wind, biomass, etc.). Geothermal energy is also a promising alternative energy source with great potential, both for private homes and small apartment buildings.

Nonetheless, geothermal boreholes need to be carefully designed (as do water boreholes) in order to protect the groundwater resources they go through.

A borehole for installing a geothermal heat pump in a private home

A borehole for installing a geothermal heat pump in a private home (2008).


BRGM's involvement and responses

BRGM Brittany collects all the drilling declaration data, as well as data about any well structures deeper than 10 metres (see French Mining Code). Consequently, BRGM centralises and validates all data concerning geothermal drilling carried out in Brittany. BRGM also conducts awareness-raising campaigns about how to execute geothermal drilling correctly.

BRGM Brittany is actively involved in communication and training initiatives concerning very low-enthalpy geothermal systems (with heat pumps). These initiatives enable the different players to obtain consistent information about good technical practices, new regulations and feedback from local authorities or organisations that have already implemented a geothermal energy project.

Adjustments to the regulatory map of Minimum-impact Geothermal Energy in the Brittany region are also under consideration.

Geological survey campaign in the Paimpont forest, Morbihan

Geology: mapping operations and support for stakeholders

Improving and developing geological knowledge is a priority, for use in practical applications and in response to societal challenges.

The challenges

Having access to detailed geological knowledge is key criterion for many applications, for example concerning natural hazards, the rational exploitation of mineral resources, the management of groundwater circulating in geological formations, or for understanding and promoting the region's geological heritage.

Modelling of alterites in Brittany on a 1:250,000 geological map

Modelling of alterites in Brittany on a 1:250,000 geological map (SILURES programme).


BRGM's involvement and responses

BRGM has been producing geological maps of Brittany at a scale of 1:50,000 for several decades and has more recently started vectorising and harmonising these maps for each département.

However, since mapping methodologies are not all the same, certain categories of geological formations, particularly the altered parts of hard rock (surface formations), are not always clearly identified, even though they represent interesting deposits and constitute strategic aquifers in certain sectors.

Improving and developing geological knowledge is therefore a priority, for use in practical applications and in response to societal challenges (mineral resources, groundwater, natural hazards). The Regional Division in Brittany has just finalised the "Resources" component of the Brittany Regional Quarry Master Plan, on behalf of DREAL Brittany.

Les Tas de Pois, Finistère

Contact us

Would you like more information? Fill in this contact form. We will get back to you as soon as possible.
* Indicates required field

Your need

Your message

Your contact details

Validate the form

To validate this form, read our data protection policy and validate the security test to confirm that you are a human user.

About the personal data collected on this form

  • Purpose of the form: to enable BRGM to respond to a request for information you have made.
  • Users of the data provided: the departments in charge of communication and user of information systems reception, support and assistance, who may share the data with persons or departments concerned by your request in-house at BRGM and/or with subcontractors or service providers.

Your rights

Within the limits of the Regulation, in particular Articles 15 to 22 of the GDPR and having provided proof of identity, you have:

  • the right of information and access to your personal data,
  • the right to have your personal data rectified,
  • the right to delete or limit processing of your personal data.

To exercise these rights, please contact our data protection officer at:
Any request that constitutes an abuse of current laws and regulations may be rejected.
More information on the policy for third-party personal data protection