The Kamniška Bistrica river is 33 km long, it originates below the Kamnik-Savinja Alps, runs southward past Kamnik and Domžale, and flows in the Sava river just above the confluence of the rivers Sava and Ljubljanica. Its torrential character has resulted in regular flooding, so there has been always a tendency for its regulation and exploitation of water power. With the construction of barriers and dams for the purposes of slowing down the current, stabilization of the stream channel, insurance against erosion and fortified banks and embankments for flood protection, the river system was interrupted both
longitudinally and laterally. All riparian and aquatic species, especially fish, have been exposed to the effects of these changes. The worst damage was made to the types of fish, which migrates over longer distances. Many species couldn’t adapt to the changes in the aquatic environment, and had disappeared from the river. Numerous transverse water structures are interrupting the longitudinal connectivity of the Kamniška Bistrica river and doesn’t allow fish migrations, so essential for their existence – particularly for potamodromous fish (migrations within inland waters) and diadromous fish (migrations between oceans / seas and inland waters) which are almost extinct.
In this thesis we are getting to know the characteristics of the Kamniška Bistrica River Basin and its features, and assess the impact of numerous transverse water structures, as well as other factors that affect fish communities of Kamniška Bistrica. Our main objective is to identify those water structures, of which improvements on free passage for fish and other aquatic organisms would contribute most
largely to the improvement of longitudinal connectivity of the Kamniška Bistrica river.