Karst is a landscape characterized by caves, sinkholes, sinking streams, and large springs. Karst is formed by the dissolution of soluble rocks such as carbonates (limestone and dolomite) and evaporates (gypsum). Ground-water movement through karst aquifers is often dominated by flow through discrete solution conduits (underground rivers). However, karst aquifers may combine characteristics of diffuse, fracture, and conduit flow and ground-water storage. Recharge to karst aquifers is often rapid through sinking surface streams and through sinkholes that funnel storm water downward to the underlying conduits. Karst aquifers generally transmit ground water much further and at much faster rates than would be expected for more diffuse aquifer types. Karst aquifers are usually directly connected to surface inputs and are more vulnerable to contamination than other ground-water sources.
Karst aquifers may be studied and characterized using a variety of tools. Water tracing tests give the most reliable information concerning the direction and rates of ground-water movement in karst areas. Mapping of caves and sinkhole distributions provide a detailed look at exact flow paths and recharge points to the aquifer. Discharge measurements and monitoring at springs is a good way to determine water supply. Although ground-water models developed for diffuse-flow aquifers are not generally appropriate for karst aquifers, pump tests and water-table mapping can yield useful information for some carbonate aquifers that are not as dominated by conduit flow. We at Environmental Data have over forty years of experience in studying karst flow systems.