Created in 2002, the H+ network is the French long-term observation system for hydrogeological research. The four main goals are :


  • The production of monitoring and experimental data on subsurface structures and processes from highly instrumented sites. The main scientific questions are : the impact of heterogeneity on flow, transport and reaction processes, the development of hydrogeophysical methods and the interactions and feedbacks between subsurface and surface systems. To address those questions, many links were developed with other communities, such as geochemists, hydrologists, microbiologists and geomorphologists.


  • The coupling between measurements, theories, and models to create a long term relation between research teams interested in theoretical, numerical, and experimental aspects of flow and transport in heterogeneous media.


  • The hosting of international teams developing novel subsurface monitoring and imaging techniques. Interactions with the catchment networks (RBV), have led to the creation of the CRITEX equipment project in 2012 and the OZCAR critical zone research infrastructure in 2017. H+ coordinates the ITN project ENIGMA (European training Network for in situ imaGing of dynaMic processes in heterogeneous subsurfAce environments)


  • The maintaining of a partnership between basic research, university/continuous training, and professional expertise (consulting agencies, water management services). The H+ sites accommodate students and professionals for traineeships on the exploitation of water resources and the prevention of environmental risks.