Hydrogeological Evaluation of Water Retaining Properties of the Kosinj Reservoir (Lika, Croatia)

Abstract

Construction of the Kosinj reservoir was planned in a karst terrainon the lower part of the river Lika. Preceding studies of this areadid not completely define the water constraining elements of the terrain,and therefore the more reliable Krušćica reservoir was built. Furtherstudies were undertaken in order to evaluate in detail the terrainof the anticipated location of the dam impoundment at Kosinj. Due tothe lithological homogeneity of the karst terrain, the studies focusedon tectonics and geomorphology, with emphasis on karstification.Terrain zoning was made on the basis of hydrogeological favourabilityfor water retaining in the reservoir.The Velebit hydrogeological barrier inluences the general waterrunoff in the hinterland, as well as the depth and the direction ofadvancement of recent karstificati on processes. In the hinterland ofthe Velebit barrier the karstificat ion is shallow, increases in depth towards the sea, and is characterized by the zoned distribution of springs,estavelles and ponors. This concept played a major role in laterhydrogeological studies of the proposed reservoir.