Cave system Djula-Medvedica

Ogulin, Croatia

 16 396 m - the second longest Croatian cave 


Djula's sinkhole and Medvedica cave are connected into one subterranean system with total channel length of 16 396 m.  Entrance parts of this system (Djula, Medvedica, Badanj) are known for a long time. The first explorations were performed by Josip Poljak (1926.) and Mirko Malez (1956- 1957.). The most exhaustive exploration of the cave was performed by Marijan Čepelak and Speleological section Velebit (Zagreb)  from 1984. to 1987.
Djula-Medvedica is a contaminated subterranean system. Main contaminator is town Ogulin with its waste and sewage waters and refuse deposits by the precipice and in river Dobra. Contamination of greater or smaller rate can be observed in the majority of the cave channels. 



The town of Ogulin

Photos from speleoorietation in Djula-Medvedica cave system

Djulin ponor, 1930.
Ogulin, Matica hrvatska


Karst Waters Intitute: Top Ten List of Endangered Karst Ecosystems 

Ogulin Karst, Croatia is located in the northern Dinaric karst area and is part of the Black Sea drainage. The lowest point of known underground channels is 83.5 m deep in the Djula-Medvedica cave system. The high biodiversity of this karst ecosystem is likely due to rich organic input, permanent groundwater habitats, high diversity of surface streams and the changing of water flow directions in the area. It is one of the richest underground biodiversity sites in the world with more than 20 cave-limited species, including several endemics. The karst ecosystem is threatened from sewage and waste dumping, water extraction for the Gojak Hydroelectric Power Plant which causes the old parts of the river beds to maintain water only during extremely high water levels, the construction of highways and gasoline pipelines.


The results of the explorations 1984-1987.

From 1984. to 1987. explorations were performed by Speleological section Velebit, Zagreb. The average temperature in the cave system Djula-Medvedica is 9 oC. The difference in altitude between the highest and lowest point is 83.5 m. The cave system is divided into 3 main parts. The first part is a maze of passages between Djulin ponor and the entrance parts of the cave Medvedica. The entrance of Medvedica is 310 m away from the entrance of Djula. During the period of a low water level this is a dry part of the cave. This part of the cave system is a sort of a filter of the river Dobra, and this is the main cause of frequent floods. In the second part called Velika pletenica (a big braid) there is a main channel in the north direction. It is the most elongated part of the cave with several water flows and lakes, a part of which is very badly polluted. The third part of the cave consists of several big channels formed by a strong water flow in the SW-NE direction. Unlike the first two parts, the third one is not badly polluted and the water is rather clean. 

Because of water flows, the cave decorations are very scarce and erosive features like whirpool slugs are very common. The level of water often increases very rapidly as a consequence of heavy rainfall and snow melting. While the water level is higher, a bigger part of the cave gets completely filled with water. 
The easternmost part of the cave ends in a siphon and indicates that some water flows of the underground Dobra are directed toward the spring Bistrac. The main direction of the channels and of the water flow in the cave Medvedica is toward the north, and Gojacka Dobra is in the same direction. The strongest water flow in the third part of the cave comes from the direction of the surface Dobra sinkhole at Okruglica and Hreljin. 

The pollution of the cave system

The cave system Djula-Medveica is a typical example of human negligence of environment. It is situated under a town Ogulin and is exposed to permanent polluting. The entrance parts of Djula and especially Medvedica are the most polluted parts. The cave is polluted with sewage, drawing through the surface and with the river Dobra, especially during the period of the high water level. There are several sorts of waste: artificial solid waste (metal, glass, rubber, and plastic materials), biological waste (wood trunks and branches, dead organisms, microflora and microfauna in water), chemical waste (oil, tar, detergents). The consequences of such pollution are following: sinkholes set blocked up and threaten to flood, the underground is mechanically and bacterially contaminated. The final consequence is that the underground space is being damaged. It all directly influence the inhabitants and the living world od Ogulin region.


  1. Marijan Čepelak, Špiljski sustav Đula-Medvedica, Speleolog, 1984-1985, 2-24, Zagreb.
  2. Boris Vrbek, Some characteristics of silt of subterranean system of Djula-Medvedica in Ogulin, IAH 21st congress, Karst Hydrogeology and Karst Environment Protection, 1988, Gulin, China.
  3. Eduard Kireta, Miron Kovačić, Speleološka istraživanja ogulinskog krša, Speleološki odsjek Velebit, Zagreb, 1987.
  4. Mirko Malez, Pećina Medvedica (Ogulin), Geološki vjesnik, X, 1956., Zagreb.
  5. Mirko Malez, Đulin ponor u Ogulinu, Geološki vjesnik, VIII-IX, 1954/55., Zagreb.
  6. Josip Poljak, Geomorfologija i hidrografija Ogulina i oglinskog Zagorja. Glasnik hrv.prir.društva, XXXVII-XXXVIII, 1926., Zagreb.
  7. Josip Poljak, Pećine okolice Ogulina, V. Paklenice i Zameta. Rasprave geol.inst.kralj.Jug., sv.5, 1935.


Edited by: Dalibor Paar. Photo: Ana Bakšić, Darko Bakšić,  Dalibor Paar
Speleološki odsjek Velebit/Speleo Section Velebit

Last update: April 27th, 2008.