Man’s Influence on the Water Regime in the Karst Terrains

Abstract

Living conditions are not favourable for man in karst regions. The main reason for this is the unfavourable water regime. In autumn and winter excessive precipitation often results in the flooding of fertile poljes and river valleys, which frequently last a long time. The water is retained in these fertile areas, more than 3 months on the average; the maximum retention lasting 6 months. Immediately after the floods end, long dry periods begin. Both phenomena adversely affect the agricultural production of the area. Since the soil is fertile and temperatures exceptionally favourable (particularly in the Mediterranean regions), the agriculture could be significantly improved by the regulation of the water regime. The previously mentioned facts have since ancient times forced man, living in these areas, to build more or less significant hydrotechnical structures. All of these structures were built with the same objective, i.e. to improve the water regime, and hence, the living conditions in the region. Today, intensive works are being carried out related to the regulation of the water regime in karst. Past experience has shown that many of these works have been suboptimal. The benefit resulting from these works in one area was frequently smaller than the damage caused in another area. This frequently occurred when the system was not thoroughly studied from hydrologic and hydrogeologic standpoints. Damage occurred most frequently in the lower karst horizons, but negative effects were also seen in the higher terrains. This damage was primarily caused by the water regime and floods.