A tool box for managing karst

Karst environment is subject to specific problems such as flooding, collapses/sinkholes, or water contamination. All are strongly associated to water. A good knowledge of the distribution of heads and fluxes in space and time would help a lot to predict and manage those problems. Ideally karst hydrogeologists would like to know water heads and fluxes anywhere in the karst system! Many studies are however focused mainly either on the time aspect (e.g. time series analyses) or on the spatial aspect (e.g. geophysics). Some modelling approaches are proposed to link both aspects together, but the required effort is huge and often reserved to academic work or to a few big projects. A series of karst-specific approaches are being developed by SISKA in order to provide this type of information within a reasonable effort (Karst Toolbox). KARSYS is based on a 3D geological model of the karst aquifer, including hydrological data explicitly. This approach provides a concrete sketch of the main drainage axes, of the expected heads and on the supposed catchment area. A tool is now available on the web to apply this method on-line for any system in the World. Adding a model of the speleogenetical conditions and on the inception horizons to the KARSYS model makes possible to predict the potential position of karst channels as well as their characteristics for any type of underground construction. This is KarstALEA, which can be expanded to near-surface in order to identify the potential position of sinkholes and collapses. KarstFLOWSIM is being developed in order to be able to simulate heads and flow in a karst environment. The simulation process includes the assessment of effective recharge (evapotranspiration processes) as well as the hydraulics of flow in a partially saturated pipe network. Various levels of details can be used in KarstFLOWSIM, requiring a more or less precise descriptionof the karst conduit network. This module is used for flood assessement. KarstNETGEN is being developed to generate karst conduit networks within the 3D geological model, considering probabilities inferred in the KarstALEA model. Compared to other generators, it takes explicitly into account the spatial distribution of recharge (zones of diffuse or concentrated recharge), as well as concepts of speleogenetical levels and inception horizons. KarstVULN is a way to assess groundwater vulnerability to pollution. It will include information of KarstINDIC, which is a map of the main characteristics of the near-surface of a karst region (karst cover and geomorphology). The sketc ed Karst toolbox is being developed first and mainly for karst region in temperate and mountaino us regions (as we have in central Europe). Adjustments and extensions for other contexts (e.g. lowland karst or hypogenic karst areas) should be discussed.