Development of a karst model for the area of the Schalkauer Platte and the tunnel area of the Blessberg cave. Tunnel constructions are potentially at risk from water migration through the rock. Particularly in highly permeable karst, the modelling of water pathways is of great importance for hazard assessment. How does the karstification behaviour change due to large underground structures? How does water movement change due to concrete placement? Does groundwater quality possibly suffer? What are the effects of changing water flow in the Blessberg cave (and in other caves)? These and many other questions will be addressed with karst modelling.