Hydrogeological Relationships of the Golubinka Karst Spring in Ljuba? Bay, Dalmatia, Croatia

摘要

The Golubinka spring is a typical karst spring situated in northern Dalmatia, Croatia. The catchment area is mostly composed of limestones of the Cretaceous and Palaeogene, with some dolomitic parts. Hydrogeological barriers are composed of flysch or Quaternary sediments, and most of them are “hanging” barriers, so that the karst water can flow underneath. Many spelaeological features in the vicinity of the spring point to a typical karst conduit flowing under ground. This has been proven by tracer tests, because a connection exists to the periphery of the catchment with an apparent velocity of 8.1 cm/s. The whole area is situated in the Mediterranean climatic belt, so the precipitation distribution is quite unfavourable – summers are long, hot and dry. This is why the summer seasons usually end with sea water intrusion into the aquifer with a significant increase in chloride ion concentration. Since the spring is capped for water supply, there is a bulk monitoring system established. The data obtained were processed by means of multivariate analysis, and three main types of quality deterioration were recognized. The first is connected with pollution from agriculture and inhabited areas without sewage, the second represents occasional sea water intrusions, while the third relates to heavy rainfall events accompanied by turbidity and pollution. Together with the other conclusions, these results should have a practical purpose primarily in the matter of water protection.