Kupa River (Croatia)

Kupa / Kolpa
Kolpa at Prelesje (Slovenia)
Country	Croatia, Slovenia
Basin features
Main source	Razloge, Gorski kotar, Croatia 313 metres (1,027 ft)
River mouth	Sava, Sisak, Croatia 130 metres (430 ft)
Basin size	10,032 km2 (3,873 sq mi)
Physical characteristics
Length	297 km (185 mi)
Discharge	Average rate: 283 m3/s (10,000 cu ft/s)

The Kupa (Croatian) or Kolpa (Slovene, from Latin: Colapis in Roman times) river, a right tributary of the Sava, forms a natural border between north-west Croatia and southeast Slovenia. It is 297 kilometres (185 miles) long, with its border part having a length of 118 km (73 mi) and the rest located in Croatia.

The Kupa originates in Croatia in the mountainous region of Gorski Kotar, northeast of Rijeka, in the area of Risnjak National Park. It flows a few kilometers eastwards, receives the small Čabranka River from the left, before reaching the Slovenian border.

It then continues eastwards between the White Carniola region in the north and Central Croatia in the south. The Kupa receives influx from the river Lahinja from the left in Primostek, passes Vrbovsko, and eventually detaches from the Slovenian border having passed Metlika.

It then reaches the city of Karlovac, where it receives influx from two other rivers from the right, Dobra and Korana (which in turn is joined by Mrežnica). The Kupa continues flowing to the east, where it merges with Glina from the right as well as Odra from the left, and proceeds to the town of Sisak where it flows into the Sava River.

Fairly unpolluted downstream to Karlovac, the upper Kupa is a popular place for bathing in summer. The section from Stari Trg down to Fučkovci since 2006 is part of the Slovenian Krajinski park Kolpa nature reserve.