Impact of an inter‐basin water transfer and reservoir operation on a karst open streamflow hydrological regime: an example from the Dinaric karst (Croatia)

Abstract

Abstract:This paper describes the hydrological changes caused by inter-basin water transfer and the reservoir development on the hydrological regimes of two rivers. The Sabljaki Reservoir in the Zagorska Mrežnica River and the Bukovik Reservoir in the upper Dobra River began operation in 1959. Both are part of the hydroelectric power plant (HEPP) Gojak, whose installed capacity is 50 m 3 /s. Their water volumes at the spillway altitudes of 320Ð10 and 320Ð15 m a. s. l. are 3Ð3 ð 10 6 and 0Ð24 ð 10 6 m 3 respectively. Both the Dobra and Mrežnica Rivers are losing, sinking and underground karst rivers. A 9376-mlong tunnel provides water from the Sabljaki Reservoir to the HEPP Gojak, which was constructed in the Lower Dobra River. The Sabljaki Reservoir is located in the Plaški karst polje, while the Bukovik Reservoir is located in the neighbouring Ogulin karst polje. The consequences of the inter-basin water transfer are strong and have caused abrupt changes in the hydrological regimes of the downstream sections of both rivers. At the same time, the construction and development of both the reservoirs have also caused hydrological changes to the upstream section of the Upper Dobra River.

Long term variations of river temperature and the influence of air temperature and river discharge: case study of Kupa River watershed in Croatia

“…1). The region is characterized by complex karst hydrological/hydrogeological behavior common to the deep and developed Croatian Dinaric karst, resulting in a weakly defined hydrological drainage area (Bonacci and Andrić, 2010). A mix of continental and Mediterranean climate influences the upper part of the basin, while Pannonian climate is the most important in the lower part.…”

New interpretation of the role of water balance in an extended Budyko hypothesis in arid regions

“…are significantly changing natural hydrological cycle and breaking the original water balance to form a new balance under the new hydroclimatic conditions. For example, the transferring water becomes the new water source of the basin to evapotranspiration due to the implemented interbasin water transfer project (Bonacci and Andric, 2010). In dry regions, croplands expanded with irrigation, which increased water availability for evapotranspiration (Gordon et al, 2005).…”

Karst Aquifers—Characterization and Engineering

“…Such streamflows are more typical, significant and relatively frequent karst phenomena than is reflected in their treatment in the karst literature (e.g. Hess et al 1989;Yuan 1991;Bonacci 1999;Bonacci and Andrić 2008;Prelovšek et al 2008;Cavalera and Gilli 2009;Bonacci and Andrić 2010;Bonacci et al 2013). A synonym for a sinking and losing stream is an influent stream.…”

“…Especially in recent time anthropogenic actions in karst (inter-basin water transfer, dams and reservoirs, groundwater pumping, motorway and railway construction, etc.) strongly, suddenly and generally unpredictably affect natural hydrological and hydrogeological regime at the local and even large regional scale (Bonacci and Andrić 2010). Figure 5.2 is an attempt to present schematically all possible relationships of water circulation between two karst springs (a and b) and their topographic catchment areas (A and B).…”