Hydrography and sectioning

One of springs of Pliva near village Pljeva in Šipovo municipality

The Pliva river flows from West to East, is 26.8 kilometers long, and has an average discharge artificially set for a biological minimum of 3.0 m³ near town of Jajce at the waterfall site. Total watershed area of the Pliva is 1,326 km².^[1] Its source is some 8 kilometers upstream of the town of Šipovo near Pljeva at the foot of the mountain of Smiljevac-Jastrebnjak, where the Pliva springs out from two very strong karstic springwells at 483 meters above sea level. The main tributary of the Pliva is the Janj, that flows into the Pliva from the right, in the center of the town of Šipovo. At the confluence, both the Janj and the Pliva are approximately the same size, and both rivers have the same amount of water.

Some 12 kilometers downstream, at the village of Jezero, the Pliva flows into the largest of three lakes, Veliko Plivsko Lake, then into two smaller lakes: Malo Plivsko Lake and Okruglo Lake. After the Pliva river passed through the towns of Šipovo and Jezero, and through both Plivska lakes, it reaches the town of Jajce where it meets with the Vrbas river. The Pliva river is a left tributary of the Vrbas that, on its way north, flows into the Sava river, therefore the Pliva is part of the Sava river basin.^[3]

Geo-hydrology

The river Pliva is characterized by the specific geological nature of the terrain and distinctive morphological and hydrological features, very similar as nearby Una River.^[4] The river bed of the Pliva, from the village of Jezero to its confluence with the Vrbas, consists of tufa also known as travertine which forms travertine barriers. In this area the Pliva river has created three natural lakes, Veliko Plivsko Lake, Malo Plivsko Lake and Okruglo Lake, with countless low cascades and travertine barriers (tufa barriers), which causing these lakes to form, slowing the river and deepening it.

Hydroelectricity

Csontvary Kosztka Tivadar's 1903 painting of an old Pliva hydroelectric power station, constructed on Pliva by the Austro-Hungarian government near the end of the 19th century.

The very first hydroelectric power station in Bosnia and Herzegovina was built on the Pliva river in 1899. It was also the very first of its kind in the Balkans. This facility was constructed and exploited by Austrian industrialist Dr. Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna". The power station had an installed capacity of 8 MW, and supplied electricity for "Elektro-Bosna" situated in Jajce, the largest chemical factory for production of calcium carbide in Europe at the time. The first hydroelectrical power station in Southeast Europe became operational on 24 March 1899.^[5]

Today plans of construction of numerous small hydro power stations on the rivers Pliva and Janj are already undergo, although local population started expressing deep resentment and disapproval, and in some cases organized protests stopping ongoing works, at least for the time being.^[6][7]

Janj's "otoke"

The Janj is also considered for construction of several small hydro, but location is highly controversial as a place of great natural and environmental value.^[6][7]

Pliva watermills

There is a cluster of small wooden hut-like watermills on the Pliva, on steep ford where the water spills between two lakes, from upper Veliko Plivsko into lower Malo Plivsko lake. These mills are out of their primary function today, but are preserved and maintained as a national monument of Bosnia and Herzegovina. Local farmers used the mills to grind wheat into flour until the Second World War and some afterward, with a heyday of production being during the days of the Austro-Hungarian Empire.^[8]