Occasionally the land surface in karst regions may collapse. Most of these events are triggered by man's activities in the karstic environment. Excessive pumping of groundwater from karstic aquifers may rapidly lower the water table and calls a sudden loss of buoyant forces that stabilize the roofs of cavernous openings. Man-induced changes in surface water flow and infiltration also may cause collapse. Most sinkholes that form suddenly occur where soil that overlies bedrock collapses into the pre-existing void.
Sinkholes are subsidence or collapse features that form at points of local instability.
Their presence indicates that additional sinkholes may develop in the future. Man-made structures in the vicinity of sinkholes are at risk for structural damage unless they have been adequately designed. In populated areas sinkholes are viewed as unwanted holes in the ground. Consequently, there is a great desire to fill them in order to level the ground. However, naturally developed paths of infiltration are often blocked, leading to potential ponding and flooding on the fill.