The challenge of HOVER was to gain understanding of the controls on both natural and polluted groundwater quality across Europe using the combined expertise and data held by member states. The project was built around 6 technical axes related to i) geogenic elements naturally present in high concentration in groundwater, ii) links between aquifer microbial ecology and diversity to contaminant transforming processes at European groundwater-surface water transition zones, iii) diffuse pollution of nitrate and pesticides from agriculture activities, iv) Groundwater age and travel time distributions in European aquifers v) vulnerability assessment of pollution risk from the surface and iv) organic contaminants of emerging concern.

Beyond the fruitful technical and scientific exchange between European GSOs, the project reached producing various guidelines, thematic maps, web service tools at pan-European and pilot study scale and databases available through the Information Platform / the European Geological Data Infrastructure (EGDI). The elaboration of a web service on thermal and mineral water, allowing an overview of main physico-chemical and trace element composition of these social waters. Also three maps of valuable interest for the diffuse pollution (nitrate and pesticide) impact assessment were made available on EGDI, together with the dataset and the method elaborated: Redox potential map, transfer time of nitrate through the unsaturated zone and the nitrate stored in the unsaturated zone from 1900 up to 2000. More than 20 pilot studies on the application of more than 10 environmental tracers and supporting parameters for assessment of groundwater age distributions across Europe. The assessment of the vulnerability of the upper aquifer to pollution using the well-established DRASTIC method and COP for specific karstic areas covers a large part of EU and is made available for further studies. The various case studies, guidelines and technical document describing the groundwater age distribution gives an good overview on the availability and use of such information in Europe and the need for further development and improvement such as as a global standard for a structured database for environmental tracers and derived groundwater age distributions and vulnerability of water supply wells towards pollution from the surface. Organic contaminants of emerging concerns were compiled from published and unpublished literature giving a good overview of the monitoring status over Europe.

Project facts:

Project duration: 1 July 2018 – 31 October 2021.
Project Lead: Laurence Gourcy, Bureau de Recherches Geologiques et Minieres (BRGM).
Project page on GeoERA website:

GIS viewer for HOVER results

Through this viewer the results of the HOVER project are accessible.

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