Hydrogeology of the sinking zone of the Korana River downstream of the Plitvice Lakes, Croatia

Abstract

IzvlečekUDK 556.3(497.56) Ranko Biondić, Hrvoje Meaški & Božidar Biondić: Hidrogeologija ponornega območja reke Korane dolvodno od Plitviških jezer, HrvaškaDolvodno od Nacionalnega parka Plitviška jezera vode, ki tečejo skozi sistem jezer, oblikujejo reko Korano. Nekaj sto metrov pod to izvirno cono v času poletnih sušnih obdobij voda v strugi ponika in s časom povsem presahne. Ponorno cono gradijo zelo dobro prepustne karbonatne kamnine in šele po prehodu na manj prepustne dolomite približno 17 km nižje po strugi Korana postane stalna reka. V članku so obravnavane hidrogeološke razmere v coni ponikanja vode v strugi in odnosi s sosednjim porečjem reke Une, pa tudi možnosti prestavitve vira oskrbe s pitno vodo iz jezera Kozjak (Plitviška jezera) na novo lokacijo v ponorni coni reke Korane. V ta namen so bile izvedene hidrogeološke raziskave, izvrtanih je bilo več piezometrskih vrtin in izvedena sta bila dva sledilna poskusa za določitev smeri podzemnega toka v času nizkih vod. Rezultati so pokazali, da je v sušnih obdobjih v ponorni coni reke Korane nivo podzemne vode z aktivnim vodonosnikom približno 25 m pod strugo. To odpira možnost dodatnih raziskav za rešitev problema oskrbe z vodo in prestavitve zajetja vode na tem območju. Oba sledilna poskusa sta dokazala povezavo z izvirom Klokot (Bosna in Hercegovina) v sosednjem porečju reke Une, kar kaže na čezmejni značaj vodonosnika. Minimalni pretok izvira Klokot je približno 3 m 3 /s, maksimalni pa več kot 75 m 3 /s. Zajetje za oskrbo z vodo v ponorni coni reke Korane z izdatnostjo približno 60 l/s ne bo imelo vpliva na pretok izvira Klokot. Ključne besede: Dinarski kras, ponorna cona reke Korane, Plitviška jezera, sledilni poskus, čezmejni vodonosnik, zajetje podzemne vode. AbstractUDC 556.3(497.56) Ranko Biondić, Hrvoje Meaški & Božidar Biondić: Hydrogeology of the sinking zone of the Korana River downstream of the Plitvice Lakes, CroatiaDownstream of the Plitvice Lakes National Park, water that pass through the water system of the lakes begins its flow as the Korana River. A few hundred meters downstream of the source zone, during the summer dry periods, there are losses of water in the riverbed resulting in its total drying. The sinking zone in that area is built of high permeable carbonate rocks and with the appearance of less permeable dolomite rocks, about 17 km downstream, the Korana River becomes a permanent river. This paper focuses on the explanation of hydrogeological relations in the zone where losses of water occur in the riverbed, relationship to the neighbouring Una River catchment, as well as possibilities of relocating the source of water supply from the Kozjak Lake (Plitvice Lakes) to the new site in the sinking zone of the Korana River. For this purpose hydrogeological researches were performed, with drilling of several piezometric boreholes and two tracing tests to determine the direction of groundwater flow during the dry season. The results show that during the dry periods in the sinking zone of the Korana River the groundwater level with ac...

Early Development of the Endemic Delminichthys krbavensis (Leuciscidae, Cypriniformes) from a Karstic Field in Croatia

“…The slower rate of development could be the consequence of the lower water temperature in the aquarium, though the temperature difference between D. krbavensis and T. karsticus was not significant (17 • C vs. 18 • C in T. karsticus), but this is most likely linked with the higher water levels that lingers longer in the Krbava Polje field than in the Sušik field. The flooding and high-water levels in the Krbava Polje field persist due to the limited reception capacities of the sinkholes in the field [28].…”

Uloga nagiba padina, gustoće vrtača i analize vodne bilance u izdvajanju kompleksnog slivnog područja rijeke Slunjčice (Hrvatska)

“…2 (and Fig. 8) were collected and interpreted based on previous dye tests (Herak, 1956;Bahun, 1968;Jurak, 1983;Marušić and Ćuruvija, 1991;Garašić, 1997;Ivičić, 1999;Ivičić et al, 2003;Pavičić et al, 2007;Trpčić & Pletikosić, 2010;Mlinarić, 2012;Biondić and Meaški, 2016).…”

“…The Middle Recharge Area is interspersed by dolomite and dolomitic breccia (K1,2) with the regulation and redirection of groundwater flow acting as relative barriers. In the SE part, Korana River is sinking into Upper Cretaceous limestone; therefore, the riverbed can dry up during the summer 1.5 km downstream of source, and 10 km from the source, the riverbed is fully without water for more than 4 months (Biondić et al, 2010;Biondić and Meaški, 2016). The Middle Discharge Area is defined with true barriers formed of (NE towards SW) Upper Jurassic dolomite and limestone (J3), Middle Triassic dolomite (T2) and Upper Triassic dolomite (T3).…”

Isotope Composition of Precipitation, Groundwater, and Surface and Lake Waters from the Plitvice Lakes, Croatia

“…Plitvice Lakes, although protected from direct anthropogenic influence, cannot be protected from global changes such as climate change. Thus, the consideration of the lakes' hydrology is of most importance for the system, especially in dry summer periods [38][39][40]. Water warming was observed in the surface water and springs of the Crna Rijeka and Bijela Rijeka Rivers [33].…”