V G 222nd Working Group C Plenary Meeting 20-21 March 2012 Groundwater bodies delineation in France Susanne Schomburgk, BRGM, Water Division s.schomburgk@brgm.fr Sarah Bonneville , Ministry of Ecology, Sustainable Development, Transports and Housing Groundwater and water resource Unit sarah.bonneville@developpement-durable.gouv.fr

National Guidance document National Harmonisation Introduction Who’s doing what ? Coordinator : MEDDTL (French Ministry of Ecology, Sustainable Development, Transports and Housing ) Fulfilment : the 6 Water Agencies for the 9 mainland RBD Technical support : BRGM (French Geological Survey) National Guidance document “Circulaire” Delineation National Harmonisation Ministry/BRGM/ national expert group Water agencies BRGM

Groundwater body delineation Before the WFD: A national aquifer delineation/hydrogeology data base named “BDRHFv1” (“Base de Données du Référentiel Hydrogéologique Français” Based only on hydrogeological properties For the WFD: Construction of a new frame of reference Based on geological and hydrogeological criteria Very occasionally on pressures in order to have a stable map Exchanges between GWB are possible Deep groundwater bodies without any link with surface waters, in which no drinking water is (and will be) removed (salinity, temperature…) is not included in a GWB A GWB can present a spatial heterogeneity (qualitative and quantitative)

Groundwater body delineation 6 main types of lithology Mainly sedimentary (excluding alluvial) Alluvial Crystalline basement rocks Volcanic rocks “Intensively folded” (mountains areas) impervious “locally aquifer” + further criteria (e.g. karstic, coastal, confined/not confined …) The whole territory is covered by a GWB Limited number of GWB : ~ 500 Aquifers aggregation in order to avoid having “too many” entities “Reporting” unit and not “knowledge” unit Reasonable for the WFD reporting

Groundwater body delineation 574 GWB 533 in mainland France (15 trans-districts, 23 transboundaries) 38 in overseas territories Distribution of GWB types a very heterogeneous geology

Ranges of superposition for a GWB – French approach

Are we happy with this GWB delineation ? 10 years after the WFD, the GWB are well known and recognised by water managers, by the public, etc... But…. 10 ranges in France but at the EU level only 5 ranges seem to be wished Some limits don’t perfectly fit with the hydrogeological limits : better knowledge now than in 2004! new numerical géological mapping-system (scale :1/ 50 000) national database of boreholes with geological passes (under coverage), new local and regional hydrogeological studies Many GWB are too large and heterogeneous: difficulties to represent sub- parts « in poor status » Confined aquifers Transbondary aquifers

Delineation of confined aquifers 49 of 534 GWB in mainland France 1) At surface: according to coverage boundary, (much bigger surface if no boundary) 2) delineation under coverage of deep confines aquifer Remaining questions Depth? Lowest wells know in the aquifer? Knowledge of aquifer behaviour? Exemple : Chalkstone, very low permeability in > 50 m depth

Transboundary aquifers

Conclusion – next steps An updated GWB delineation will be available in 2012 for the river districts Loire- Brittany, Adour-Garonne and Rhône- Mediterranean /Corsica « Relatively » small changes to facilitate the next WFD reporting: Mainly adjustment of GWB boundaries following new knowledge (new hydrogeological reference system) Exemples of open questions in discussion between ministry, water agencies and BRGM(expert group): Management of depth for confined aquifers Complete coverage of the territory? Subdivision or creation of new GWB Consequences to manage Changes in the status assessment The GWB code of a borehole may change: need to link codes to the reporting period