Karst Watersheds

Karst

Karst topography is a type of landscape underlain by soluble carbonate rocks easily sculpted by water, including limestone, marble and dolomite. These regions have little or no surface drainage and subterranean drainage will eventually exit via a spring. Natural features of karst such as sinkholes, caves and springs often result in spectacular landscapes. (Fetter, C.W.).

Watersheds

A watershed is a drainage basin, or an area of land that drains into a common water body. The extent and shape of the watershed is determined by how the topography of the region directs runoff . Precipitation moves over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, eventually depositing them in lakes, rivers, wetlands, and even underground sources of drinking water.

Karst Watersheds

A karst region is defined by a landscape with sinkholes, springs, and streams that sink into subsurface caverns. In a karst watershed water enters directly, as surface runoff, or indirectly by water percolating through soil and bedrock. Thus the watershed is typically three dimensional with water flowing across the surface as well as vertically underground. The streams and surface runoff enter sinkholes and caves, and bypass natural filtration through soil and sediment. This dramatically increasing the possiblilty of pollution and sedimentation build up in the ground water as well as the surface water that it often feeds.

Sinkholes

Associated with karst topography is the development of sinkholes, which are depressions created by the removal of soluable rock by groundwater (Tarbuck and Lutgens, 2002). Sinkholes can range from a meter to over 100 meters wide (Murck & Skinner, 1999). Areas that display karst topography and have potential for sinkholes development are portions of Kentucky, Tennessee, southern New Mexico, southern Indiana, central and northern Florida, and the Appalachian Mountain Great Valley Limestone Belt (Schmidt, 2001).

Kentucky Karst

Approximatly 55% of the Kentucky is underlain by karstic limestone in 3 of 7 physiographic provinces and along the margins of the Eastern and Western Kentucky Coal Fields (KGS 1985). This allows for a great diversity in the state’s caves and karst since each karst region has unique characteristics due to differing hydrogeologic conditions (KGS 1985). The abundance of karst in Kentucky affects everything from the state’s biodiversity (Barr 1958) to the history of human settlement (Andrews 2001; O’Dell 2001). The widespread and intense karstification of the region also poses tremendous environmental impact issues due to continued population growth and industrialization (Crawford 2001). Increasingly, the karst areas of Kentucky face rapid development and a losing battle due to lack of knowledge about our subsurface environment.