Sinkhole classification and nomenclature

Abstract

Karst is defined as a landscape that is distinguished by its underground drainage, so that its landforms evolve in response to rainfall and surface water flowing into the ground. Consequently, river valleys cannot develop in a mature karst. Instead, drainage and consequent fluvial erosion is centripetal towards points where the water sinks underground. Dendritic systems of linear valleys are replaced by internally drained closed depressions as the dominant surface landforms of karst. The erosion processes that create closed depressions are essentially downward, and therefore may involve subsidence that makes them a geohazard to engineers. The surface depressions are matched by the underground landforms, caves, which, by their very existence, create the second engineering geohazard in karst.