The construction of Version 3 of the BDLISA database on the limits of aquifer systems in all of mainland and overseas France was completed in October 2022.
After Version 2 was issued at the beginning of 2018, consolidation work based on user feedback continued from 2019 to 2022. In the end, about 20% of the entities have seen changes since the previous version (in terms of attributes and/or geometry). These corrections were made through the BDLISA Forge collaborative space in which users of the repository can share their expert knowledge with us.
Changes have also been made in recent years to improve targeting and several new features are now included in the new dataset, such as:
- Review of the geometry of some of the basement entities: the hydrogeological characterisation of these features, which until now was imprecise in the BDLISA, has been significantly refined (this work, partially carried out in the Armorican Massif and in Auvergne, will continue for V4).
- Revision of the geometry and characterisation of entities in part of the Auvergne: when the first versions of BDLISA were produced, some 1:50,000 geological maps of the region did not yet exist.
- Creation of a new table on the lithology of the entities: each entity is now also described by one or more lithologies (always including a "dominant" lithology). For this purpose, a major review of the associated SANDRE lexicon was carried out by adapting the BRGM lithological classification. This first version will obviously be supplemented in future versions.
- Improvement of the additional entity layer, including the removal of existing overlaps with the main alluvial entities.
Work on BDLISA began in 2006 after a conceptualisation and testing phase. The studies were conducted for each region by the regional agencies of the Ministry of Ecology, the water and environment offices and BRGM's regional divisions. Local and regional authorities, research organisations and civil engineering consultancies were also involved. BRGM was commissioned to build up the reference database and to consolidate its contents on the national scale, as required by the National Water Data Plan (SNDE).
With the completion of database construction, work is now focusing on approximately three-year iterative cycles, after which any anomalies observed by users will be corrected and proposed improvements incorporated using scientific and technical advances in knowledge of the subsurface.
Map of outcropping hydrogeological entities, classified by type, in Version 3 of BDLISA, the French hydrogeological database.
What is BDLISA for?
BDLISA (Base de Données des LImites des Systèmes Aquifères) was set up to provide maps for users in mainland and overseas France of the aquiferous geological formations known as "hydrogeological units" and defined in accordance with common rules. A single system of identification is applied for all formations, which are described in terms of their hydrogeological characteristics. The information is entered into a database linked to a shared set of reference maps that are freely available for consultation by the public. Any user of BDLISA can easily display, process and exchange the information attributed to one or more hydrogeological units.
BDLISA is a reference geographical database that divides France into hydrogeological units (geological formations with or without aquifers). A hydrogeological unit is part of a geological area which is:
- defined at a particular geographical scale, referred to as the "level",
- linked to a type of geological formation, referred to as the "theme",
- defined by its aquiferous potential, referred to as its "nature",
- characterised by a type of porosity (which identifies the main patterns of water circulation), referred to as the "environment",
- characterised by the presence or absence of a free and/or captive water table, referred to as its "status".
BDLISA is a reference database that:
- contributes to the development and improvement of the reference datasets being built up to form the Water Information System (SIE) on groundwater:
- the reference database on groundwater masses, established in line with Directive 2000/60/EC of the European Parliament and Council of 23 October 2000,
- the reference database on groundwater monitoring sites,
- provides coherently designed maps of groundwater resources within French territory,
- incorporates information associated with each hydrogeological unit (level, theme, nature, environment and status),
- facilitates exchanges of the data between different users.
BDLISA also contributes to the production of knowledge required to guide and implement national and EU policies on groundwater.
How can I access BDLISA?
A new dedicated website for access to BDLISA is now available on line, which has been designed to centralise and improve access to all BDLISA information and explanations. The site is available at: bdlisa.eaufrance.fr
As a consequence of the creation of this new website, the distribution procedure for BDLISA has changed. All data considered essential to the construction of BDLISA are in the "BDLISA reference base" (as defined for the water information system) and downloadable from the SANDRE website. An "operational" version has also been produced, containing supplementary data but also the "Reference base" data, rewritten to offer a series of relevant data products for users. This is available at : bdlisa.eaufrance.fr
BDLISA is available in the SHP (QGis, ArcGIS®), geodatabase (ArcGIS®), SQLite and Geopackage (OGC®) formats. Instructions for use are downloadable with the database: BDLISA may be reused under the open licence conditions applying to public information.
BDLISA is also available through cartographic web services that allow displays of the hydrogeological units via a GIS or web application. Details on these services may be consulted on the Eaufrance portal (under the heading "Les services de valorisation").
The project was funded by the Ministry for the Ecological and Inclusive Transition, the French Biodiversity Agency (AFB), the Water Agencies and the BRGM. The work was undertaken in accordance with a national methodology developed by SANDRE (the national administration agency for water data and databases), which is also responsible for distributing the database.