The Sava spans Central-
Southeast Europe, flowing through Slovenia, Croatia, Serbia and along the Bosnia-Herzegovina border. Its total length is , including the Sava Dolinka and the Sava proper. As a right tributary of the
Danube, the river belongs to the
Black Sea drainage basin. When the Sava Dolinka headwater is excluded from its course, the Sava River is the
third longest tributary of the Danube, slightly shorter than the
Tisza and the
Prut—the Danube's two longest tributaries. It is also the largest tributary of the Danube by
discharge. The river's course is sometimes used to describe the northern boundary of the
Balkans, and the southern border of the
Central Europe. Before the
breakup of Yugoslavia in 1991 the Sava was the longest river lying completely within the country.
From the source to the Sutla and
Trbovlje The Sava Dolinka rises in the Zelenci Pools, west of
Podkoren in the
Upper Carniola region of Slovenia at above sea level (a.s.l.), and flows east, past Kranjska Gora to
Jesenice, where it turns southeast. At
Žirovnica, the river enters the
Ljubljana Basin and encounters the first
hydroelectric dam—
Moste plant—before proceeding to the east of the glacial
Lake Bled towards Radovljica and confluence of the Sava Bohinjka, at a.s.l. Downstream of Radovljica, the Sava proceeds southeast towards
Kranj. Between Kranj and Medvode, its course comprises the
Lake Trboje and the
Lake Zbilje reservoirs, built for the
Mavčiče and the Medvode power plants. The Sava then flows through the capital of Slovenia,
Ljubljana, where another reservoir is on the river, adjacent to the
Tacen Whitewater Course. There the river's course turns east and leaves the Ljubljana Basin via
Dolsko, at a.s.l. (at confluence of the
Ljubljanica and the
Kamnik Bistrica). The course continues through the
Sava Hills, where it passes the
Litija Basin with the mining and industrial town of
Litija, the
Central Sava Valley with the mining towns of
Zagorje ob Savi,
Trbovlje, and
Hrastnik, turns to the southeast and runs through the
Lower Sava Valley with the towns of
Radeče,
Sevnica, and
Krško. The course through the Sava Hills forms the boundary of traditional regions of Lower Carniola and
Styria, At Radeče, the
Vrhovo hydroelectric dam reservoir stands. The latter is site of the
Krško Nuclear Power Plant, which uses the Sava River water to dissipate excess heat. The easternmost stretch of the Sava's course in Slovenia runs to the south of
Brežice, where it is joined by the Krka, and the river ultimately becomes a border river between Slovenia and
Croatia, marking of their border near confluence of the
Sutla (). At that point, the Sava reaches a.s.l. after flowing through Slovenia and along its border.
From the Sutla to the Una The westernmost part of the Sava River's course in Croatia, takes the river east, through the western part of the
Zagreb County, between
Samobor and
Zaprešić. The area encompasses forests interspersed by
marshes and lakes formed in
gravel pits. As the Sava approaches the capital of Croatia,
Zagreb, the marshes give way to urban landscape, but there are surviving examples of the gravel pit lakes, such as the
Jarun, and the
Bundek within the city. At the western outskirts of Zagreb, there is the western terminus of the
Sava–Odra flood-relief canal connecting the Sava to the
Odra River plain which is intended to act as
flood control retention basin. The canal has been built in response to the most destructive
flooding of the river that occurred in Zagreb in 1964, when one third of the city was flooded and 17 people were killed. The city itself marks the western extent of the Sava River basin area especially prone to flooding, spanning from Zagreb to confluence of the river in
Belgrade,
Serbia. East of Zagreb, the river turns southeast again further through the
Central Croatia, to the
Sisak-Moslavina County, the city of
Sisak, reaching a.s.l. The city of Sisak marks the westernmost extent of the Sava River navigable to larger vessels. Navigation conditions on the river are poor due to limited
draft and fairway width,
meandering of the river,
bridge clearance restrictions, poor
fairway markings as well as presence of sunken vessels and other objects, including
unexploded ordnance. The ordnance is left over from various conflicts including the
World War II,
Croatian War of Independence,
Bosnian War, and the
1999 NATO bombing of Yugoslavia. Before reaching confluence of
Una at
Jasenovac and a.s.l, the Sava River traces
Lonjsko polje Nature Park, encompassing marshes frequently flooded by the Sava and its tributaries in the area.
From the Una to the Drina (left) and
Slavonski Brod,
Croatia (right) Downstream of confluence of the Una River, the Sava is once again tracing an international border—between Croatia and
Bosnia-Herzegovina. Its meandering course runs generally eastwards along
Bosanska Gradiška, and
Slavonski Brod to
Županja, where it turns south to
Brčko. There, the river resumes its predominantly eastward course towards
Sremska Rača and confluence of the
Drina River. The right bank of the Sava, in this segment of its course, belongs to Bosnia-Herzegovina (with Bosnia's all three administrative entities,
Republika Srpska,
Federation of Bosnia and Herzegovina and the
Brčko District, having gateway to the river), while the opposite bank belongs to Croatia and its Sisak-Moslavina,
Brod-Posavina and
Vukovar-Srijem counties, except in the area of
Jamena and further downstream—which belongs to Serbia and the province of
Vojvodina. No cities in this segment of the course span the river. It is an international frontier, three times seeing adjacent key settlements facing one another: Bosanska Gradiška, Bosanski Brod, and Brčko in Bosnia and Herzegovina, opposite
Stara Gradiška, Slavonski Brod, and
Gunja in Croatia. The segment between the Una and the Drina confluences, corresponding to the Sava flowing along the border of Bosnia-Herzegovina, exhibits small change of elevation, such as from
ASL at Jasenovac to ASL at Brčko
gauges: over of the river between them. The river below Zagreb has a 0.4‰ slope (gradient) on average, much less steep than the course in Slovenia, where the average slope exceeds 0.7‰. This results in the Sava's meandering course running through a wide plain bordered by
wetlands.
From the Drina to the Danube (river on left) near the right bank of the
Great War Island and
Kalemegdan Downstream from the confluence of the Drina, the Sava River changes its eastward course to northeast, until it reaches
Sremska Mitrovica, whence it flows southeast and then south to
Šabac, before finally turning east towards Belgrade. Most of the river's course in Serbia represents a border between province of Vojvodina, on the left bank, and
Central Serbia, on the right bank. Exceptions to that are in area around Sremska Mitrovica, where both banks are in Vojvodina, and downstream of
Progar suburb of Belgrade where both banks are in Central Serbia. The river meanders and forms wetlands there as well—the most significant centering on
Obedska bara oxbow lake. The Sava River forms several large
islands in this segment of the course, with the largest among them—
Ada Ciganlija in Belgrade—connected to the right bank by a pair of artificial
embankment dams forming
Lake Sava since 1967. The Sava discharges into the Danube, after reaching a.s.l. as its right tributary at the
Great War Island off the easternmost tip of
Syrmia in Belgrade, away from the Danube's confluence and the Black Sea.
Settlements Population in the Sava River basin is estimated at 8,176,000, and includes four capitals: Belgrade, Ljubljana,
Sarajevo and Zagreb. All except Sarajevo, are on the river banks and represent the three largest settlements found along the river. Belgrade, at the lowest end of the river, is the largest city in the basin with urban population of 1,135,502. Ten municipalities of its outer conurbation have combined population of 1,283,783, taking in many mutual suburbs. The Belgrade
metropolitan area has a population of 1,639,121. Zagreb is the second largest city on the river, comprising population of 688,163 living in the city itself, and 802,588 in the city-administered area. Together with the Zagreb County, largely corresponding to various definitions of the city's metropolitan area, it has a combined population of 1,110,517. Ljubljana is the third-largest city on the banks of the Sava, encompassing a population of 258,873 living in the city itself and 265,881 in the city-governed area. The largest city of Bosnia-Herzegovina on the river is Brčko, whose urban population is estimated at 40,000. Other cities along the river, with populations of 20,000 and larger, are Slavonski Brod (53,473), Šabac (52,822), Sremska Mitrovica (37,586), Kranj (35,587), Sisak (33,049),
Obrenovac (24,568), and Bosanska Gradiška (est. 20,000). ==Watershed==