KARST TERRANES AND ENVIRONMENTAL ASPECTS

Karst is a complex geological phenomenon that relates to terranes composed of limestone, dolomites, gypsum, halite, or other soluble rocks. Protection of groundwater in karst against pollution is needed because of the high velocity of its flow (several hundreds of thousands of meters per day) and where polluted materials are carried without being filtered. Protection of karstic aquifers against pathogens and rapidly degradable chemicals is carried out for the catchment areas with an estimated delay time of 60 days and for a distance of more than 30 m. Tracer methods have recently become quite useful in karst regions; a tracer may respond as a multiimpulse because of different flow lines, flow velocities, and water aquifers. Therefore, if a total water balance has to be established, nearly all answer-back impulses should be considered.