Case Studies from the Dinaric Karst of Slovenia

Fig. 42: Cerkniško polje with meandering river Stržen and ponoring places Rešeto and Vodonos (photo: A. Mihevc).of the polje; there are some Jurassic dolomitesin the area. On W and NW the Cretaceouslimestone are presented.During the last centuries, a lot of plansfor the hydro melioration of polje have beenmade, but not any of them were realized. In1965 it was proposed to make Cerknica poljea permanent lake; in the years 1968 and 1969,entrances to the caves Velika and Mala Karlovicawere closed by concrete walls and 30 mlong tunnel was made to connect Karlovicawith the surface, but small effect of retentionin dry period and less moistened years wereassessed.The flattened bottom of Cerkniško poljeis regularly flooded for several months in autumnwinter and springtime; at floods it altersto spacious karst lake. Lower waters are sinkingmostly in marginal swallow holes and innumerous ground swallow holes and estavellas,which are disposed in central polje’s bottom.Principal ponor caves and swallow holesare disposed at the polje’s northwest border.Outflow from the polje was not orientedto one channel, rather to a mesh of channels,which about 200 m from the edge of poljecombine into a couple of larger galleries. Theyare generally low, because the bottom is filledwith alluvia. Alluvium at altitude of 550 m isdistinctive in all ponor caves; its thickness ispossibly the same as a thickness of alluvia inJamski zaliv.Karst of Dolenjska and KolpaThe karst of Dolenjska (Lower Carniola)occupies an area between the Ljubljanskobarje (Ljubljana moor), the eastern edge ofthe Bloška planota (Bloke plateau), the riverKupa/Kolpa, the mountains Gorjanci, thesettlement Krško and the southern of theDolenjsko podolje (Dolenjska lowland). It isalso described as the covered lowland karst55