It follows distinctive paths, and contaminants remain in concentrated masses called plumes. However, in karst limestone aquifers, flow is not laminar. Contaminants are not concentrated in one area. Instead, they travel quickly throughout the entire aquifer. Water can move across the valley in 5-6 hours, carrying contaminants with it.
Caves are common in karst terrains.
Over thousands of years, the water slowly dissolves the limestone and forms passageways and huge chambers. In the limestone valleys of central PA, many small streams plunge underground at sinkholes and follow underground channels for a few hundred feet or for several miles. They reappear to form springs that are at or above the water table. The largest springs in central PA originate from solution channels that are in limestone. Some of these springs flow directly into surface streams.