Case Studies from the Dinaric Karst of Slovenia

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Ulica pečina is 125 m long, 10-15 m widecave with two entrances. Cave is developedin Lower Cretaceous thick-bedded limestone.The cave represents relict of old cave system,which was opened by denudation to the recentsurface. The bottom of the cave is composedof clastic sediments, clays, rocks andgravel. There is evidence of fast sliding of sedimentinto the lowest part of the passage as aresult of periglacial processes in the cave. Thethickness of roof above the cave is about 10 m.On the south side, the cave opens on theslope of the hill, while on the north side cavewas continues in unroofed cave Ulica. Theunroofed cave Ulica is a 250-m long series ofelongated depressions. The unroofed cave isabout 10 m deep and 20-30 m wide. The wallsof the unroofed cave are mostly steep, thefloor of it are composed of sediments, on onespot with massive flowstone. Continuation ofthe unroofed cave is not clear, possibly is towardsnorhwest, where are some large boulders,the remnants of collapsed cave ceiling.Even if the caves are not of the same system,they were most likely developed at thesame time, and were probably connected withthe sinking rivers from the flysch. Dating ofRačiška pečina sediments shows their ages upto 3.4 Ma. After the presumed lowering of thesurface with denudation rate of about 50 m/Ma with this age there was about 100 m of therock above the caves removed since de depositionof the dated sediments.Fig. 46: Plan and cross-section of cave Ulica pečina and unfoofed cave (figure made by: A. Mihevc).65
Use of Karst and its ProtectionThe Nature Conservation Act in Sloveniaprovided a basis for the overall conservationof biodiversity and protection of valuablenatural features (included karst surface andunderground) as part of Slovenia’s naturalheritage. Nature conservation legislationand the Cave Conservation Act (from 2000)regulate the protection and conservationof caves. This Act governs the protectionand use of underground caves, protectionarrangements, protective measures and otherrules of conduct, including the restoration ofpolluted or damaged caves.The conservation of caves is often difficultto implement because important segments oflife on karst take place above them. Becauselarge caves along underground rivers areimportant economically as tourist caves, as asource of water supplies, and for science, itis necessary to protect them or exploit themwithout devaluating them in the process.Unnecessary activities that often take placeabove the caves could easily be avoidedthrough more reasonable planning. Forinstance the entire Kačna jama cave lies belowthe town of Divača. While it is impossible tomove settlements, the sewage treatmentplant and its discharge could easily be installedfarther away from the cave. It is also notnecessary to build an industrial zone directlyabove the cave passage that connects theKačna jama cave and Škocjan Caves, a worldclassphenomenon. The industrial zone couldbe built one kilometer further north and notthreaten the underground world. This is notjust about the conservation of the two cavesbut about the tourist exploitation of the cavesas well; the situation will be much worseif the surface above the caves is built up.Along the underground Reka River is anotherproblem with the Sežana sewage treatmentplant in Kanjeduce, which is located abovethe underground passages of the cave and itsdischarges are far from achieving the requiredstandards. The entrances to Postojna Cave,Planina Cave, and the caves in Rakov ŠkocjanPark face similar problems. Thoughtlessencroachments are destroying importantassets and society will benefit from themmuch less in the future.There is a problem with tourist visits tocaves. For example two hundred years oftourism have left a number of negative tracesin Postojna Cave. Some have damaged thenatural condition of the cave, while othersthreaten the tourist exploitation of the caveand have reduced the value of the cave. Whilethese changes are negative, they could beminimized if we are aware of them. Stalactiteshave been removed, the floor of the cave hasbeen changed excessively, and large amountsof dust have accumulated in the entranceparts of the cave. Other activities in the vicinityof the cave may present an even greater threatto the cave than tourist exploitation: the poorcondition of the sinking Pivka River due to theinefficient treatment plant, the construction ofindustrial buildings in the immediate vicinity,for example, on the site of former militarybarracks near Veliki Otok, abandoned militaryfacilities above the cave, and a car dump sitebeside the old road toward Planina. Suchactivities should be moved farther from thecave since they present a serious threat andare certainly not examples of good practice.66
Page 2 and 3:
Andrej Mihevc, Mitja Prelovšek, Na
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ContentsGeographical Position and G
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Fig. 2: Coastal part of Dinaric kar
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ogy started. In 1531 a lawyer from
Page 11 and 12:
include numerous data and general o
Page 13 and 14: GeologyNadja Zupan HajnaThe Dinaric
Page 15 and 16: ceous. The final disintegration of
Page 17 and 18: Fig. 11: Locations of Jelar Breccia
Page 19 and 20: ClimateMitja PrelovšekThe Dinaric
Page 21 and 22: 311 mm/a; Zaninović 2008) and incr
Page 23 and 24: 24Fig. 16: Spatial distribution of
Page 25 and 26: ocks (such as Eocene flysch, Lower
Page 27 and 28: absent. Downstreamparts of the cany
Page 29 and 30: GeomorphologyAndrej MihevcIn folk l
Page 31 and 32: long. They are smoother especially
Page 33 and 34: is now depositing. Best known are t
Page 35 and 36: Structural poljes are dominated by
Page 37 and 38: Fig. 28: Typical dolines of Dinaric
Page 39 and 40: the disintegrated collapsed rock at
Page 41 and 42: on Northern Velebit, where three ca
Page 43 and 44: Land UseNadja Zupan Hajna, Andrej M
Page 45 and 46: for ‘bare limestone desert’ -th
Page 47 and 48: Fig. 38: Grančarevo dam in the upp
Page 49 and 50: KrasThe Kras is a distinct plateau,
Page 51 and 52: in this part of the Kras (Mihevc 20
Page 53 and 54: dolomite barrier along the Idrija w
Page 55 and 56: of Dolenjska (Gams, 1974; Kranjc, 1
Page 57 and 58: Fig. 44: Blind valleys of Matarsko
Page 59 and 60: ly several dozen meters deep. Shaft
Page 61 and 62: smaller than the higher ones. The r
Page 63: tion in the Divaški kras (Mihevc 1
Page 67 and 68: Gams, I., Vrišer, I. (Eds.), 1998:
Page 69 and 70: lems.- Dela 38, Raziskovalni center
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Case Studies from the Dinaric Karst of Slovenia

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