EGU23-6405, updated on 08 Jan 2024
EGU General Assembly 2023
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Investigating the hydrological behaviour of the Upper Pivka Valley (Slovenia)

Cyril Mayaud1,2, Blaž Kogovšek1,2, Metka Petrič1,2, Nataša Ravbar1,2, Matej Blatnik1,2, and Franci Gabrovšek1,2
Cyril Mayaud et al.
  • 1Karst Research Institute - ZRC SAZU, Postojna, Slovenia (
  • 2UNESCO Chair on Karst Education, University of Nova Gorica, Glavni trg 8, 5271 Vipava, Slovenia

The Pivka River is a 20 km long stream located 40 km SW from Ljubljana (Slovenia), which disappears in the world famous Postojna Cave. While the river flows permanently on flysch rocks in the valley lower part, water is only present temporarily in the valley upper part due to the karstic nature of the aquifer located below the river. This aquifer is assumed to be linked to the larger Javorniki karst aquifer that belongs to the catchment of the Unica and Malenščica Springs, which drain water from the whole region. During high water period, the regional groundwater level rises up to 50 m, and 17 temporary lakes might appear on the valley surface. Because the hydrological situation in the Javorniki karst aquifer is assumed to affect flooding in the Pivka Valley, the interaction between both need to be understood. A network of nine automatic stations recording water level, specific electrical conductivity and water temperature at a 30 min interval has been progressively established in the valley since 2020. The three years dataset has been analysed with data collected in the water active caves of the Javorniki karst aquifer and at the Unica and Malenščica Springs. Results allowed elaborating a conceptual hydrological model of the region. They emphasized that the karst aquifer below the Upper Pivka Valley acts as an overflow of the Javorniki karst aquifer during high water periods, while it flows back into the Javorniki karst aquifer and further toward the Unica and Malenščica springs during the recession.

How to cite: Mayaud, C., Kogovšek, B., Petrič, M., Ravbar, N., Blatnik, M., and Gabrovšek, F.: Investigating the hydrological behaviour of the Upper Pivka Valley (Slovenia), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6405,, 2023.