RMZ-M&G 2003, 50 Protection of the kast aquifers in the river Kupa catchment area and sustainable development BOIDAR BIONDIÆ 1 , RANKO BIONDIÆ 2 & SANJA KAPELJ 2 1 Faculty of Technical Sciences, Varadin, University of Zagreb, Hallerova aleja 7, Varadin, HR-42000, Croatia 2 Institute of Geology, Department of Hydrogeology and Engineering Geology, Sachsova 2, HR-10000, Croatia; E-mail: rankobiondic@zghtnethr Abstract: River Kupa catchment area is one of the most significant water resources in Croatia, located in the border area with Slovenia About 85 % of total amount of water of the river Kupa discharges on the Croatian side so the catchment areas are of the significant dimen- sions It is the typical karst aquifers of Dinarides, with relative fast water exchange in the ground, with high velocities of groundwater flow, opened towards the surface by numer- ous swallow holes, therefore the aquifer of high vulnerability and high risk High quantities of high quality springs water (about 35 m 3 /s) give the strategic importance to the whole area, and the water resources get the high strategic importance of future development of the west part of the Republic of Croatia In this paper the investigation results of the whole water system on Croatian side are presented Thereby, the available investigation methods were used; from the classical hydrogeological approach, the detail hydrologic calculation of water balance, the groundwater tracing, hydrogeochemical analyses and modelling and finally the protection zones and protection measures for the whole area It is emphasized that the catchment areas lie in the zones of major traffic corridors, oil pipelines, railway and numerous settlements with developed wood industry and all of those subjects, with pre- vention measures and remediation activities, should satisfy very strict protection require- ments for the karst aquifers Although they are the karst aquifers of high risk, the solutions exist, even the possibilities for lowering the existing risk from todays development level of the whole area Keywords: Kupa river catchment area, karst springs, protection system, groundwater, hydrogeology INTRODUCTION Karst aquifers recently in the public water supply get the growing importance in the Europe, especially in Mediterranean and Alps regions, where on many places presents the only source of potable waters Value in the water supply grows foremost because of the high quality of water and the position of the majority karst catchments in relatively weak developed moun- tain areas of very short loaded space Croatia has significant high quality water resources in the karst area of Dinarides, from which the whole Adriatic coast and numerous towns and settlements in continental area have organized the water supplying systems The special place by this has the water re- sources in the catchment of Kupa River, which flows through borderland between the Croatia and Slovenia The largest part of the huge karst springs, and main river spring has been placed on the Croatian side The catchments extend deep in the area of Gorski Kotar, and protection problems mainly are bound the management system on the Croatian side RMZ - Materials and Geoenvironment, Vol 50, No 1, pp 33-36, 2003 33 Scientific paper