Karstic waters, a water resource for the future? How can groundwater resources be sustainably managed in karstic regions such as the Jura or the Prealps, while the climate changes, the exploitation of the soil through agriculture and urbanization increases and the use of the underground in itself becomes more diversified (drinking water, geothermal applications, various infrastructures)?

Lay summary
With a reserve of 120 km3 and an annual resource of 6 to 8 km3, the karstic aquifers represent approximately 80% of the reserve and 50% of the groundwater resources in Switzerland. And yet, karstic aquifers present characteristics that are very different from those of other types of aquifers. Also, they are not well known in Switzerland, because there are no maps or documents that describe them systematically.
What effects will the following points have on karstic aquifers?
- Climate changes which progressively induce an adaptation of our drinking water supply system.
- Tunnel drilling, various borings (for example for the exploitation of heat from the underground).
- Water prospecting for power production.
- Infiltration of fresh water in more or less controlled quantity and quality.

Objectives and methods
The aim of this project is to establish a national inventory of the karstic aquifers. A pragmatic and practically-oriented documentation concept is being elaborated. The approach will combine three-dimensional models with geological and hydrological data. Various actual instances of use will also be taken into account, so that the concept can be adapted to practical needs and usage conflicts. In this way, information on a national scale can be put together, analyzed and compared, at least at the level of the large karstic aquifers.

Sustainable karstic aquifer management is only conceivable if a certain balance can be achieved between the different exploitation forms and the natural functioning of this particular system. The results of the project build a useful basis that can be directly applied to the management of the underground karstic waters in Switzerland. They will be made available to administrations, stakeholders from the private sector (e.g. hydroelectric companies) as well as the general public.