KArst system Self-organization for water resource Protection and vulnERability – KASPER

We will develop various modeling tools (WP1) to verify the theory of decoupled chemical and mechanical processes and to better understand the conditions and locations of formation of the main conduits and cavities. These models will be linked to laboratory dissolution experiments (WP2), with a particular focus on observing the processes occurring before and after sample rupture. The relationship between laboratory experiments and field measurements will be studied through metric analysis and comparison (WP3).

These models will be linked to laboratory dissolution experiments (WP2), with an emphasis on observing the processes occurring before and after sample rupture. Dissolution experiments of carbonate samples will be conducted in the laboratory, with various initial heterogeneities and several monitoring tools used throughout the experiments (X-ray tomography imaging, tracers, geophysical measurements, etc.).

The relationship between laboratory experiments and field measurements will be studied through metric analysis and comparison (WP3). Field measurements and a multi-scale comparison, linked to the conclusions of numerical models and laboratory experiments, will be carried out. This step will be conducted at the Durzon site in Larzac, using the Karst3D database. This will improve our understanding of the formation of conduits and cavities in karst systems, as well as the properties of the surrounding matrix rock and its storage capacity. This information is essential for the sustainable use of these systems, particularly in the context of climate change, which is likely to affect the karstification potential of these natural environments.

Understanding the formation of karst systems is essential for the management and protection of water resources, as well as other resources stored within these systems (oil, gas, etc.). In particular, characterizing the hydrodynamic and storage properties of these systems is one of the objectives of research theme A1 of the French National Research Agency (ANR). In this context, studying the formation of ghost rocks (or weathered zones) and the self-organization of flows within these systems will allow us to understand how and where they form, and how this formation process determines the storage properties of these systems, notably through the porosity of the weathered zones. This knowledge will provide key information for field applications related to resource management and protection, as well as for predicting the impact of climate change on the properties of karst systems. These properties are essential to ensure the sustainable exploitation of resources stored in these natural environments. Conducting laboratory experiments under various hydrochemical conditions will allow us to reproduce different models of karst formation, from the hypothesis of total removal of dissolved matter during the passage of the acidic solution through the sample, to configurations where chemical and mechanical processes are decoupled. Numerical simulations will be used to define the range of validity of these representations and to assess the impact of the initial structures with additional synthetic systems.

We also anticipate that the conclusions drawn from the laboratory experiments and numerical simulations will contribute to the understanding of the data and measurements acquired in the field. The structural properties and data obtained through tracer tests and geophysical measurements will be compared at both scales and used in large-scale models. They will also feed into the karst3D database, in which the different karst systems can be classified according to the formation theory applicable to each example. This database constitutes a valuable open resource for the scientific community.

The results obtained within WP1 and WP2 will be published in open-access, peer-reviewed international journals (four publications are expected) and presented at national and international conferences (one international conference for the postdoctoral researcher and doctoral student, and one European conference and one national summer school for the doctoral student). Publication and conference participation costs not included in the KASPER project budget will be covered by research funding from other IPs.

Laboratory and field data, as well as models, will also be published in open access (see "Open Science Practices" in section I.c.).

The postdoctoral researcher and doctoral student will have the opportunity to participate in science festivals through the activities of the Géosciences Montpellier research unit and as part of the training offered by the GAIA doctoral school for the doctoral student (see the last paragraph of "Team and Resources" in section II.a.). Most of the topographic data from caves will come from speleological associations, conferences on karstogenesis, including the use of topographic data from caves in academic research, will be organized.