engleski

High Waters in Vrana Lake (Dalmatia) – Protection and Risk

The lakes situated in the coastal karst areas are very sensitive hydrological systems whose aquifers are dynamically balanced with the sea. One of those systems is Vrana lake in Dalmatia which, by its surface of more than 30 km2, is the largest lake in Croatia. The lake is a cryptodepression, already in the 18th century connected to the sea by an artificial canal in order to create agricultural fields from the peripheral parts of the lake. Due to its outstanding natural characteristics the lake and the surrounding area has been declared a Nature park. However, the lake system salination appearances, the largest of which was in 2008, represent a threat to the natural eco-system. Therefore a need for finding the proper lake system salination protection measures has risen, primarily within the context of a possible elevation of the canal level by which the lake is connected to the sea. Such elevations also raised issues of large water protection for the influential part of Vrana field around the lake, which resulted in conducting and analyzing the high waters occurrences described in this paper. Since only a part of the surface inflows into the lake are hydrologically controlled, the high waters analysis was conducted by balance model monitoring – based on the analysis of lake water change dynamics. The analysis has established the statistical principles of high waters occurrence within the lake system, the intra-annual interdependence of high waters occurrence in relation to the previous minimal water level conditions as well as the corresponding trends.

lake; karst; high waters; Vrana lake; Dalmatia

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