This experimental site is based on an extraordinary hydrogeological object: the “Fontaine de Vaucluse” spring,  which has the highest average annual flow in France, and one of the highest in Europe.
This hydrosystem constitutes a unique observatory of flows in an unsaturated zone, due to its thickness (on average 800 m), the caving access provided by more than ten kilometers of karst networks, and the presence of the UAR LSBB whose 4 km of sub-horizontal galleries provide access to flow points of impenetrable karst conduits at depths ranging from 30 to 500 m.

Societal and scientific challenges

Carbonates provide around 13% of groundwater used for AEP globally (Stevanovic, 2017) and 40% across France (Marechal et al., 2020).
The very heterogeneous structure of carbonate hydrosystems is the root of a dual functioning: slow flows within the network of pores and fine fractures or cracks coexist with rapid flows within the karst network. This particularity causes or intensifies risks and issues such as flash floods, resource variability, vulnerability of water quality, etc.
As all the compartments of the water cycle interact with each other and with the biosphere, future increase in anthropogenic pressures and change in climate will exacerbate these risks, while the evolution of karst water resource will impact surface flows and the functioning of ecosystems.
Research work carried out within the observatory aims to help respond to these challenges. It focuses on improving the understanding and conceptual and numerical modeling of the hydrodynamic and hydrochemical functioning of the different compartments of karst hydrosystems, in connection with the plant cover and in the context of global change.

Link to research infrastructures

The Vaucluse Fountain experimental site – LSBB is part of the national observation services (SNO) H+ and KARST which aim to synergize research led in small-scale hydrogeological sites and karst hydrosystems. These long-term observations feed the OZCAR network to answer the same general question: the adaptation of the Critical Zone to a changing planet.

Datasets

Measurement period: 1992 – present
Multidisciplinary observations are carried out at different scales:
    • local scale on the LSBB site - characterization approaches combining hydrochemistry, hydraulic tests and hydrogeophysics are developed,
    • scale of small hydrosystems - monitoring of several sources on or around the impluvium of the fontaine de Vaucluse,
    • scale of the carbonate platform - fontaine de Vaucluse is the privileged observation point,  hydrodynamic monitoring in drilling and cavities.
The data is accessible via the SNO H+ and KARST databases