Le service d’observation H+ a été créé en 2002, avec trois missions principales : La mission première de l’observatoire H+ est de maintenir et de coordonner un réseau de sites expérimentaux capables de fournir des données pertinentes – y compris des chroniques ou expériences long terme – pour la compréhension du cycle de l’eau et des éléments transportés dans les aquifères. Le couplage mesures / théories / modèles est une mission fondamentale de l’observatoire H+. La modélisation, à quelque niveau qu’elle soit, est un outil indispensable à la prédiction. L’observatoire a pour vocation de créer un lien pérenne entre les équipes de recherche intéressées par les aspects théoriques, numériques ou expérimentaux des transferts en milieu hétérogène. L’observatoire H+ a enfin pour mission d’établir un partenariat entre la recherche fondamentale, la formation initiale et continue, et l’expertise : bureaux d’études, régie de l’eau, ... Les sites de H+ accueillent des étudiants et des professionnels dans le cadre de formations sur l’exploitation de la ressource et la prévention des risques environnementaux. La base de données contient toutes les mesures effectuées sur les différents sites, chroniques, expériences, mesures de géophysiques et données spatialisées.

The vadose zone is the main host of surface and subsurface water exchange and has important implications for ecosystems functioning,climate sciences,geotechnical engineering,and water availability issues. Geophysics provides a means for investigating the subsurface in a non-invasive way and at larger spatial scales than conventional hydrological sensors. Time-lapse hydrogeophysical applications are especially useful for monitoring flow and water content dynamics. Largely dominated by electrical and electromagnetic methods,such applications increasingly rely on seismic methods as a complementary approach to describe the structure and behavior of the vadose zone. To further explore the applicability of active seismics to retrieve quantitative information about dynamic processes in near-surface time-lapse settings,we designed a controlled water infiltration experiment at the Ploemeur Hydrological Observatory (France) during which successive periods of infiltration were followed by surface-based seismic and electrical resistivity acquisitions. Water content was monitored throughout the experiment by means of sensors at different depths to relate the derived seismic and electrical properties to water saturation changes. We observe comparable trends in the electrical and seismic responses during the experiment,highlighting the utility of the seismic method to monitor hydrological processes and unsaturated flow. Moreover,petrophysical relationships seem promising in providing quantitative results.

This borehole hydrogeophysical logging data include optical imaging,acoustic logging,induction and electrical resistivity,natural and spectral gamma radioactivity,fiber optic measurements an d multiparameter probe logs.

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates). Note that soil and flux tower parameters are available in the dataset Soil-atmosphere exchange.

Available data include monitoring data (flow rates in springs or tunnels,weather parameters,piezometric levels and pumping flow rates).

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates).

This borehole hydrogeophysical logging data include optical imaging,acoustic logging,induction and electrical resistivity,natural and spectral gamma radioactivity,fiber optic measurements an d multiparameter probe logs.

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates).

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates).

Available data include monitoring data (weather parameters,piezometric levels and pumping flow rates).