Why do sinkholes form?
Sinkholes form in karst terrain principally from the collapse of surface sediments into underground cavities in the limestone bedrock. Slightly acidic ground water slowly dissolves cavities and caves in the limestone over a period of many years. When the cavity enlarges to the point that its ceiling can no longer support the weight of overlying sediments, the earth collapses into the cavity. In the less catastrophic, type of sinkhole, a bowl-shaped depression forms at the surface, usually over a considerable period of time. Well drilling data suggests that much of the underlying bedrock in Florida is riddled with cavities of differing size and depth. However, relatively few ever collapse and directly effect roads or dwellings. Karst terrains develop in areas underlain by carbonate rocks such as limestone. They often have drainage systems that are reflected on the surface as sinkholes, springs, disappearing streams or even caves. The term karst, therefore, refers to the terrain and the
