Hydrology
Farming in karst areas must take into account the lack of surface water. The soils may be fertile enough, and rainfall may be adequate, but rainwater quickly moves through the crevices into the ground, sometimes leaving the surface soil parched between rains.
A karst fenster is where an underground stream emerges onto the surface between layers of rock, cascades some feet, and then disappears back down, often into a sinkhole. Rivers in karst areas may disappear underground a number of times and spring up again in different places, usually under a different name (like Ljubljanica, the river of seven names). An example of this is the Popo Agie River in Fremont County, Wyoming. At a site simply named "The Sinks" in Sinks Canyon State Park, the river flows into a cave in a formation known as the Madison Limestone, and then rises again a half-mile down the canyon in a placid pool. A Turlough is a unique type of seasonal lake found in Irish karst areas which are formed through the annual welling-up of water from the underground water system.
Water supplies from wells in karst topography may be unsafe, as the water may have run unimpeded from a sinkhole in a cattle pasture, through a cave and to the well, bypassing the normal filtering that occurs in a porous aquifer. Karst formations are cavernous and therefore have high rates of permeability, resulting in reduced opportunity for contaminants to be filtered out.
Groundwater in karst areas is just as easily polluted as surface streams. Sinkholes have often been used as farmstead or community trash dumps. Overloaded or malfunctioning septic tanks in karst landscapes may dump raw sewage directly into underground channels.
The karst topography itself also poses difficulties for human inhabitants. Sinkholes can develop gradually as surface openings enlarge, but quite often progressive erosion is unseen and the roof of an underground cavern suddenly collapses. Such events have swallowed homes, cattle, cars, and farm machinery.
The Driftless Area National Wildlife Refuge in Iowa protects Discus macclintocki, a species of ice age snail surviving in air chilled by flowing over buried karst ice formations.
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