Hydrogeology of the cave Vetrovna jama in karst aquifer north from Planinsko polje (Notranjska region, central Slovenia)

Abstract

For one year we have been measuring level and temperature of underground water in Vetrovna jama, to find out the origin of underground water and hydraulic characteristics of the cave and karst aquifer north east of Planinsko polje (karst of Notranjska region, central Slovenia). Similar parameters as in Vetrovna jama were measured also at the Unica River and at the Cerknica Lake. Cave is located only 2.7 km north from the polje and is fed by the Unica River, according to measurements. But in contrast with our expectations, we did not directly detect underground water flow, which drains from the Cerknica Lake. Hydrographs measured in Vetrovna jama were compared with those measured in some other caves within the aquifer. Hydrographs from Vetrovna jama are only partly comparable with hydrographs obtained in other monitored caves, as comparison shows no statistical significant correlation. Final conclusion would be that drainage of water between "eastern" and "western" part of karst aquifer is limited. Moreover, outflow from Vetrovna jama strongly depends on local hydrogeological restriction, such as supposed rockfall under Laška kukava collapse doline.