Provence-Alpes-Côte d’Azur (PACA)
Geological map of Provence-Alpes-Côte d’Azur.
BRGM Provence-Alpes-Côte-d'Azur is based in Marseille. The regional division's operations essentially focus on the region's major challenges, namely natural hazards (geological and coastal), groundwater resources, the quality of the environmental compartments (groundwater and soil), as well as resource management in the face of climate change, demographic pressure and the scarcity of building land. The operations are carried out by a multidisciplinary team of about ten people, closely supported by specialists from BRGM's scientific and technical centre in Orléans or from other regions.
The Mediterranean and the Alps: the French region with the largest expanse of natural areas
The region is typified by its Mediterranean coastline, along which most of the population is concentrated, and its hilly hinterland which stretches up towards the less densely populated Alpine mountain range. It is the third most populous region in France (with 4.5 million inhabitants). The population density (144 inhabitants/km2) is slightly higher than the national average.
This vast region is extremely diverse in terms of its geology and history and can be divided into several large geographically coherent areas: Provence, which is marked by the plains of the Rhône River, the Camargue coastline, the limestone cliffs around Marseille and a large area of plains and hills extending to the foothills of the Alps, the southern Alps and the French Riviera to the east. The coastline is quite unique in that it has been extensively urbanised, while also being home to France's first urban, coastal and marine National Nature Park (the Parc des Calanques in Marseille). The coastline varies greatly (with rocky, sandy and developed areas) and needs to be managed closely to meet the region's major challenges, be it in terms of protecting people and property or safeguarding the area's tourist appeal.
Natural areas cover 75% of the region, meaning Provence-Alpes-Côte d'Azur has a larger expanse of natural areas than any other French region.
In economic terms, the Côte d'Azur - the part of the coastline between Toulon and the Italian border - is one of the most popular regions in France for domestic and foreign tourists. In 2017, the tourist sector accounted for nearly 10% of the region's jobs. The area's industrial activity (notably petrochemicals) is located mainly around the Etang de Berre (Berre Lake)
Provence-Alpes-Côte d'Azur also has a wide spectrum of research activities, particularly in the fields of risk management (natural and human-induced) and geosciences. The cities of Marseille and Nice have historical ties with countries to the south or further afield and this has led to joint research programmes with European partners and other countries around the Mediterranean.
Public and private partners
BRGM has experience of partnerships for projects that help shape public policy, public and private research for responding to the needs of industry, and of training at all levels of decision-making and regional planning. It works with public partners: Europe (ERDF, INTERREG), Prefectures, DREAL, DDT(M), DRRT, DRAAF, ADEME, AFB, ARS, Conservatoire du littoral (Coastal conservation agency), Regional Council, Departmental Councils, City Councils and Communities of Conurbations, Rhone-Mediterranean-Corsica Water Agency, Société du Canal de Provence, Water management Syndicates (Huveaune, Arc, Argens, Var, etc.), Chambers of Agriculture, Regional Nature Parks (Alpilles, Sainte Baume), and several scientific partners:universities Aix-Marseille and Nice (CEREGE, GEOAZUR), IRSTEA, IFREMER, CEREMA, etc.
References and projects
Sustainable management of water and water uses
The water supply in PACA comes from various sources depending on the area in question: for a large part of Provence, the water is supplied by the Société du Canal de Provence and the Marseille Canal Management Authority. With more than 5,000 kilometres of canals and pipes, they essentially draw on the reserve water from the Durance and Verdon rivers, which they transport and distribute in the départements of Bouches-du-Rhône, Var, Alpes-de-Haute-Provence and Vaucluse.
In the east of the region, the water supply comes from the Var River, the Vésubie Canal and the water table of the Roya River, which flows from France into Italy.
In the Var département, part of the supply comes from water extracted from the aquifers in the Argens catchment basin.
Since Alpine surface waters make up the predominant part of the regional water supply, this has led to a relative lack of interest in developing knowledge about the area's groundwater, especially in the western part of the region (with the exception of the Crau water table). However, concerns about safeguarding water supplies and the potential impact of climate change are driving the region's authorities to carry out surveys and improve their knowledge of deep or alluvial catchment basins and to pursue water saving initiatives all over the region, notably for urban and agricultural uses. Indeed, in certain areas of Provence there is an imbalance between the quantity of water available and the needs. Moreover, this imbalance could affect other areas in the future due to the impact of climate change. More than 25 secondary catchment basins are affected by quantitative imbalances (SDAGE 2016-2021), and almost half of these are located in western Provence.
A campaign of video surveys and multi-parameter logs for the CONCERT-EAUX project.
© BRGM - Florence Rivet
BRGM's involvement and responses
In view of the proximity of the sea and the fact that decades of human of activity have led to the deterioration of the quality of water resources, BRGM (with the support of government departments (DREAL), local authorities (Region, Département, etc.), the Water management Syndicates and the Rhone-Mediterranean-Corsica Water Agency) has developed methods for characterising, monitoring and modelling flows through multi-year research programmes. This includes:
- salinity surveys of the Crau water table, with additional studies in partnership with the Grand Port of Marseille (GPMM) as part of the GAMBAS project concerning the active management of the anti-salt intrusion dam,
- studies of water resources contained in deep karsts: the PROVENKARST project (in collaboration with the Water Agency) aims to identify groundwater resources that are not linked to surface water (which represents a large volume in Provence), and which could help maintain the quantitative balance in a context of mounting pressure on the resource due to climate change.
BRGM also carries out quantitative monitoring of 30 groundwater bodies that are part of the Rhône-Mediterranean catchment basins, using more than 80 remote-transmission piezometers that make it possible to read and disseminate groundwater levels in real time.
In addition, the remarkable CONCERT-EAUX project allows us to anticipate and better understand the impact of climate change on water resources in the Mediterranean environment. Conducted within the framework of an INTERREG programme with the CNRS, the University of Genoa and the Liguria region, the CONCERT-EAUX project concerns the Roya Valley area. Notably, BRGM has set up a web-based water resource observatory providing direct 3D displays of the water-level time series measured across the catchment area.
Better integration of risks to ensure sustainable spatial planning
There are many natural hazards in the region and no municipality is exempt from them. The region is affected by every type of risk, including two types that are considered to be major risks at the national level: earthquakes and floods. The region is also affected by gravity-related risks, landslides, risks linked to clay shrinkage and swelling, or the dissolution of gypsum. The effects of climate change will also increase the risk of coastal flooding on part of the region's coastline. This phenomenon ultimately raises questions regarding public safety as well as major social and economic issues, which could be trickier to deal with in the future if they have not been prepared for in advance.
Land collapse in Luc-en-Provence on 8 October 2014 (Var).
BRGM's involvement and responses
BRGM plays a major role in understanding and managing natural risks. It notably provided scientific and technical responses to the various issues set out in the 2015-2018 Regional Strategy for Preventing Natural Risks (established under the aegis of the Regional Prefecture), as well as for the 2019-2021 Regional Strategy. In particular, the Regional Strategy can draw on the Regional Observatory of Major Risks set up by BRGM PACA, the governance of which is shared between DREAL PACA, the Provence-Alpes-Côte d'Azur Region and BRGM.
BRGM's teams therefore support government departments and local authorities in characterising the risk of ground movements (collapse of coastal cliffs, sinkholes due to the dissolution of Triassic gypsum, mountain landslides, etc.), through visual surveys or geophysical measurements and the development of numerical models.
Scientific studies carried out in partnership with the Region and the DREAL for the Regional Observatory of Major Risks also makes it possible to:
- better determine erosion rates on coastal cliffs or the consequences of forest fires in the Maures massif,
- consolidate and pool knowledge of coastal dynamics, by modelling the risks of flooding in the Camargue and providing access to the Storm Database,
- implement a tried-and-tested multi-risk approach (used in the Asses-Verdon-Vaire-Var, Durance area) by producing a graduated damage scale and relevant indicators,
- understand the links between heavy rainfall and landslides in the Alpes-Maritimes département,
As regards earthquake risks, BRGM has seismological expertise which is drawn upon for regional studies, notably for the purposes of crisis management exercises (RICHTER exercises carried out in Cadarache in 2012, in Alpes-de-Haute-Provence in 2013 or Alpes-Maritimes in 2016) as well as for mapping and developing innovative tools for risk management. The European INTERREG RISVAL project (2017-2020) coordinated by the Aosta Valley Autonomous Region (Italy), working alongside the Piedmont Region, ARPA Piedmont, the ISTerre laboratory, GEOAZUR, CEREMA and ENTENTE, for example, is relaunching and extending scientific cooperation on this subject in the Alpine region, at the French and French-Italian cross-border level.
As regards the management of risks linked to polluted sites, soils and sediments, BRGM regularly provides decentralised government departments or ADEME with support to design diagnostic processes, develop or assess monitoring and rehabilitation processes for environments polluted by previous economic activities, or to assess complex pollution files or clean-up processes (industrial wasteland, former mining sites).
For this type of situation, BRGM draws on several areas of expertise (hydrogeology, site studies, GIS, geotechnics), as in the case of the POLMAR land plans, for which it is helping DREAL to design and size temporary storage areas for marine pollution residues.
Contributing to the rational, sustainable and responsible management of primary and secondary mineral resources
The region has fallen behind in terms of waste planning and management. This is reflected by insufficient household sorting, a lack of professional waste collection facilities, weak waste recycling channels, strong pressure on storage capacities and considerable inter-departmental and international flows (Italy). To better manage resources, the region needs to promote a circular-economy model, which consumes fewer natural resources, is less dependent on fossil fuels and promotes local economic development.
Map of deposits of national interest in northern Vaucluse.
BRGM's involvement and responses
Faced with this challenge, DREAL PACA has asked BRGM to help draw up the Regional Quarry Plan; in this respect, the Provence-Alpes-Côte d'Azur region is a pilot region, since it was the first region to draw up such a plan, set out in the Decree of 15 December 2015. BRGM was responsible for carrying out the inventory of primary and secondary resources at the regional level. It has thus drawn up a resource map that identifies the potential primary resources available in the region, including the distribution and diversity of the resources.
As regards secondary resources, the plan focuses on identifying deposits of resources that can be used to replace primary resources extracted from quarries. The plan provides figures about the locations, quantities (in tonnes) and uses of the region's available secondary resources. Exchanges of resources with the PACA region's neighbouring départements and countries have also been taken into account.
Overall, it can be noted that the flows currently being removed could be better directed towards the recycling sector (glass, plaster and construction waste in the broadest sense), and that large deposits (in terms of volume) are still available, with excavated earth and construction waste.
Finally, several supply scenarios have been analysed and their effects assessed in order to determine the measures required to avoid, reduce and, if necessary, compensate for any impact on the environmental issues identified.
Drawing on knowledge of the subsurface, its resources and uses for the purposes of energy transition
Due to the region's strong economic and demographic development, and its relative under-development in terms of major national nuclear-power plants, energy transition is a major challenge. Indeed, the region's stated objective in the Regional Master Plan for Spatial Planning, Sustainable Development and Territorial Equality (SRADDET) is to increase diversified energy production to achieve a carbon neutral region by 2050. With this in mind, it can be noted that the region has huge potential in terms of renewable energies, including solar, wind and geothermal.
Former mine pit with the concrete pit headframe of the Morandat shaft, which will become the Joint Development Zone (ZAC) for exploiting the geothermal potential of mine waters.
BRGM's involvement and responses
Geothermal energy has development potential for local needs, depending on the respective hydrogeological settings. In Gardanne, for example, BRGM is helping to convert former flooded lignite mines to exploit their geothermal potential to supply heating and cooling networks.
In addition, to support the sustainable development of geothermal energy, BRGM has the expertise to draw up maps of potential sources at different scales, including areas with geological risks. It is also developing monitoring methods aimed at avoiding conflicts of use between human activities in areas under cities.
Improving knowledge of the subsurface and developing a geological infrastructure
Most environmental and spatial planning issues cannot be properly addressed without a good knowledge of the subsurface. The nature of the subsurface has a direct bearing on many issues, including the heritage value of the region's geological diversity, its material and mineral resource needs, as well as the availability of building land in this highly popular tourist region.
Cover page of La Géologie des Bouches-du-Rhône.
BRGM's involvement and responses
BRGM provides public access to all available geological knowledge about the regions of France by publishing geological maps at a scale of 1:50,000 as well as 40,000 drilling and borehole records from the subsurface database (BSS, available on BRGM's InfoTerre portal).
In 2018, the new geological map of Marseilles was published, at the same time as the project to map the Alps and Peripheral Catchment Basins project was launched, as part of the new French Geological Reference (RGF) programme. Since 2012, the RGF programme has taken over from the 1:50,000 map programme. In line with an objective dating back nearly 200 years, this programme aims to provide France with a high-level scientific geological data platform, to meet the needs of society. In particular, it should provide a solid scientific basis for addressing the challenges of urban development with the help of innovative tools. One such tool is Building Information Modelling (BIM) which, when coupled with 3D models of the subsurface, will make it possible to draw up and exploit digital models that mirror an actual structure (building) or the infrastructures of the region's major cities (Marseille, Toulon, Nice) in order to assess their status at any given moment and anticipate how they will change over time.
BRGM is also involved in promoting the value of the region and its attractiveness (while ensuring that its assets are protected) by publishing books and guides on regional geology. Through its publications, BRGM contributes to raising the awareness among the general public, schoolchildren and elected representatives about the importance of protecting geodiversity to support biodiversity. These publications also simply give readers the chance to enjoy discovering the environment.