Ecology & Conservation
Karst regions are notorious for environmental problems, and a knowledge of caves is one of the most important assets in being able to solve them. The most serious are described here: 1) land instability — as caves enlarge, the overlying land tends to subside into them. This causes sinkholes, cracking of foundations and roads, disruption of pipelines, and diminished property values. 2) Problems of water supply — most of the groundwater flow in a karst area is through caves. and unless these cave locations are known, the patterns of groundwater flow cannot be predicted. Well yield tends to be high (if solutional openings are encountered) or rather low. 3) Poor water quality — the unfortunate thing about wells with high yield in cave areas is that their water quality is almost always low.
Wells with smaller yield are generally of higher quality. Contaminants travel rapidly through caves and undergo very little filtering. Every effort should be made to avoid spills, leakage, or dumping of wastes in sinkholes. On a more positive note, caves give us information about the distribution of certain oil reservoirs and ore deposits. It is clear that a knowledge of caves is essential for a proper assessment of any of these phenomena. The study of caves is rapidly growing in importance, and only recently has it been recognized as a truly significant science of its own.
Every cave is sensitive, whether the cave is open to the public as a show cave or is an unexplored, wild cave. This fragile environment cannot repair itself like the environment on the surface. Because the cave is not visible to people living on the surface we often assume our actions will have no effect on the subsurface. This is as far from the truth as one can imagine. One of the most damaging environmental problems facing caves today is water pollution. Water is as vital to the life of a cave as it is to the life of humans. We have learned how caves are developed by groundwater seeping into the subsurface. Many caves also have rivers which start on the surface and enter the cave through a sinkhole or other entrance. Therefore, any materials that will dissolve in a liquid can enter the cave environment. Rain water and runoff carry pesticides from farming. Industrial wastes dumped into rivers may enter the cave if the river itself runs underground farther downstream.
In many communities, raw sewage is pumped into caves with the idea that it will be cleaned up by the cave system. If any potential pollutant is allowed to remain on the surface over a cave, eventually, the pollutant will reach the cave environment. All of these factors will contribute to the destruction of the cave and any life present. An even more serious threat is to the water we drink.
In western Wisconsin and eastern and southern Minnesota, much of the water we drink comes from aquifers which are riddled with caves. Much of the water that replenishes these aquifers comes from rainwater seeping into the ground. Caves provide a more direct route for the water to reach the water table through soil and rock. As a result, contaminants reach the water table in a matter of a few hours or days rather than months or years. In rural areas, people will have wells and septic systems. This also may be true of small towns and villages. It is not unusual to find a homestead or even a village or town pumping well water from the same rock unit as they dispose of the sewage. We must keep in mind that anything we put into the ground will eventually reappear in our drinking water. In one instance, dye flushed down the toilet in a house reappeared in the kitchen sink in less than 45 minutes. How much filtering has THAT water seen?Return to Cave Ecology