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Standardising data on water and aquatic environments

Millions of data points on water, aquatic environments and their uses are produced in France to assess water status and guide public policy. These data must be standardised to enable their exchange and comparison. Standardisation in turn requires the use of shared data repositories. Two new repositories have been created, one for hydrogeological data and the other for the hydrographic network of Mayotte.

The purpose of the water information system (WIS-F) is to collect, produce, manage and disseminate data that is consistent, comparable and compliant with French and European regulations. That requires the development of data repositories that are available free of cost to all water stakeholders in France to ensure their effective use. The repositories must facilitate the exchange of WIS-F data (water status, pressures, prices, etc.) among users and with other information systems, notably the European water information system (WISE).

A new hydrogeological data repository

The new hydrogeological data repository BD Lisa (database on the limits of aquifer systems) informs on five aspects of aquifers, i.e. their geographic size (national, regional or local importance), type of geological formation, type of aquifer, type of porosity, presence of water, thus making it possible to draw up precise hydrogeological profiles. On the national level, the repository provides information on water resources and their evolution over time, an assessment of aquifer resistance to drought, vulnerability to pollution and the risks of rising water tables. On the regional level, it can be used to draw up hydrogeological atlases and evaluate water resources. On the local level, the repository can assist in drafting piezometric maps or in modelling aquifers. Internet services have also been created to map hydrogeologic units in contact with the surface, also showing the depth of each unit.

Contact : l.chery@brgm.fr

 

Hydrographic data repository for Mayotte

The BD Carthage Mayotte® data repository is now accessible and provides in-depth information on the very dense hydrographic network of the island and its many specific aspects. Initiated in 2008 at the request of the Mayotte Prefect, the project involved numerous partners, including the Mayotte environmental agency, Onema, Irstea, BRGM, IGN, etc. The data may be accessed in the form of maps on the 1 : 25 000 scale. Each hydrographic unit is identified by a code and described by general topographic (width of river, name, location, etc.) and geometric information indicating the links between rivers. Some of the data must still be validated. Aerial photographs (BD ortho® database) and a digital terrain model (DTM), both in 3D, were used to create the repository. In addition to its use for police work and for studies on natural hazards, BD Carthage Mayotte® will also serve to update the database on water bodies and for the new status report due out at the end of 2013. It is part of BD Carthage®, the repository for the hydrographic network that has covered all of France, including the overseas territories, since 2012. Mayotte, the most recent French department, now complies with the French and European requirements.