Principal investigator : Olivier Bour, Professor, Géosciences Rennes,  University of Rennes 1

Deputy scientific manager, Hydrogeology : Tanguy Le Borgne, Professor (physicien CNAP), Observatoire des Sciences de l'Univers de Rennes, University of Rennes 1

Deputy scientific manager, Hydrogeophysics : Cédric Champollion,Associate Professor, Géosciences Montpellier, University of Montpellier   

Site managers

PLoemeur : L. Longuevergne (U. Rennes 1)

Poitiers : G. Porel (U. Poitiers)

Mallorca : P. Pezard (CNRS Montpellier)

Larzac : C. Champollion (U. Montpellier)

Auverwatch : H. Celle-Jeanton (U. Franche-Compté)

LSBB : K. Chalikakis (U. Avignon)

Hyderabad : J.C. Maréchal (BRGM)

Database manager

A. Battais (U. Rennes I)

Supporting institutions

Coordination Laboratory : Observatoire des Sciences de l'Univers de Rennes (OSUR), UMS 3343 CNRS

Participating institutions:

- Departments : GéosciencesRennes (UMR 6118 CNRS), IC2MP (UMR 7285), Géosciences Montpellier (UMR 5243), EMMAH (UMR INRA-UAPV 114), Geosciences Azur (UMR 6526), BRGM, LSBB (UMS 3538 INSU/UAPV/UNS)

- Observatories : Observatoire des Sciences de l'Univers de Rennes (OSUR), Observatoire de Recherche Méditerranéen en Environnement de Montpellier (OREME), Observatoire de la Côte d'Azur (OCA)

- Institutions :CNRS / INSU, BRGM, INRA, Université Rennes I, Université de Poitiers, Université de Montpellier II, Université d'Avignon, Université de Nice, Laboratoire Souterrain à Bas Bruit LSBB

- Partner institutions :NGRI (India), CSIC (Spain), Forschungszentrum Jülich (Germany)

Structure and operation

The H+ Observatory is built on 5 components :

The hydrogeological sites

The kernel of the observatory consists of 7 sites, which are complementary in terms of geological medium, exploitation and research objectives. The sites are heavily instrumented for long term monitoring. The main objectives of the long-term monitoring are i) to analyze the hydraulic and chemical response of aquifers to perturbations (e.g. pumping), ii) to quantify the impact of climatic or land-use changes, and iii) to obtain measurements of fluxes and element transport in the hydrological cycle over time scales representative of these systems that are characterized by a broad range of response times. These long-term observations are complemented by experimental campaigns to characterize physical and chemical heterogeneity, target hotspots, which cannot be accessed by classical observations, and parameterize hydrological models. Each site is managed by a scientific team which determines the scientific questions, ensures the long-term functioning of the site and the link with the other sites and observatory networks, develops the experimental protocols and the instrumentation, and makes available the data to scientist community through the H+ database.

The experimental sites

The experimental sites are distinct from the hydrogeological sites. Their function consists of the testing and validation of technological developments and/or experimental procedures. They are often to be found in the vicinity of the research laboratories that are partners in H+. The three main sites are the Centre d’Etude et d’Enseignement de Lavalette, near Montpellier (south of France), the site of the Beaulieu campus in Rennes (Brittany, France), and the experimental platform in Strasbourg (Alsace, France).

The observation, measurement, and experimentation tools

The ability to acquire relevant information on the properties and the structure of the hydrogeological medium is a key element in the success of the H+ observatory. The pool of existing powerful tools and the development of new instruments ad methods for the characterization of the subsurface are therefore among the main tasks of the observatory. Thus, the different H+ team continuously acquire and develop innovative hydrogeophysical tools for long term observation and field experiments.

The database

Data archiving and dissemination is a key objective of the H+ observatory. The H+ network is committed to an open data policy. To extract data, users create an account in the H+ database that they obtain after agreeing with database chart. A significant effort has been done during the last years to ensure that the main datasets of all sites are continuously inserted in the database. The average number of data values entered every years by H+ teams is 50 million.

H+ data can be currently extracted in three different ways:

i)                 by formulating requests in the advanced interface,

ii)                by consulting pre-defined requests that allow a direct download of the main datasets on each site (there are currently over 280 pre-defined requests at the network scale),

iii)               by the google earth interface that allows a spatial visualization of sites and measurement locations (Figure 1). There are on average 200 downloads per year through this interface.


Figure 1: Illustration of the integration of the LSBB (left) and Hyderabad sites (right) in the H+ database and its google earth interface. Left: location of flow measurement stations in the LSBB tunnel, right : instrumented boreholes on the Hyderabad site.

The H+ Meetings and evaluations

Regurly-held meetings between partners in H+ provide discussions on all aspects of the site development (measurements, instrumentation, experiments, database, ...), but also on basic scientific aspects, in particular the relation between data and models. The meetings represent an essential element of the observatory, because they allow (i) to share the technical or experimental knowledge, (ii) to discuss the scientific orientations of the observatory, (iii) to open the debates to new questions or methods by inviting exterior researchers.

The H+ network is regularly evaluated by its funding agencies: CNRS and the ministry of research. In addition to this national evaluation system, the H+ partners have decided to set up an international advisory board, which provides an external advice on the scientific and observation strategy of the H+ network and of the individual sites that compose it. The two first international advisory board of H+ met in 2008 and in 2018 at Rennes.