The Opava (, ) is a river in the Czech Republic, a left tributary of the Oder River. It partly forms the Czech-Polish state border. It flows through the Moravian-Silesian Region in the Czech Republic and along the Opole Voivodeship in Poland. It is formed by the confluence of the ÃÂerná Opava and Stà ÂednàOpava streams. Together with the ÃÂerná Opava, which is its main source, the Opava is long, making it the 15th longest river in the country. Without the ÃÂerná Opava, it is long.
The first written mentions of the river are from 1031 (as Vpa) and 1062 (as Opa). The words apa, opa were Celtic words for 'water' or 'river'. The suffix -ava is of younger origin and also denotes 'water'. The source streams of the Opava are called ÃÂerná Opava ('black Opava'), Stà ÂednàOpava ('middle Opava') and BÃÂlá Opava ('white Opava').
From a water management point of view, the Opava, ÃÂerná Opava and Stà ÂednàOpava are three different watercourses with separate numbering of river kilometres. The Opava itself is formed by the confluence of the ÃÂerná Opava and Stà ÂednàOpava in the territory of Vrbno pod PradÃÂdem at an elevation of , and is long. The stream of BÃÂlá Opava flows to the Stà ÂednàOpava shortly before its confluence with the ÃÂerná Opava and is also considered the source of the Opava.
In a broader point of view, the Opava (as ÃÂerná Opava) originates in the territory of Zlaté Hory in the Hrubý JesenÃÂk mountain range, on the slope of the OrlÃÂk mountain at an elevation of , and flows to Ostrava, where it enters the Oder River at an elevation of . It is long, making it the 15th longest river in the country. The river forms of the Czech-Polish border. Its drainage basin has an area of , of which is in the Czech Republic.
The sources and longest tributaries of the Opava are:
The most notable settlement on the river are the cities of Ostrava and Opava, named after the river. The river flows through the municipal territories of Vrbno pod PradÃÂdem, Karlovice, à  iroká Niva, Nové Heà Âminovy, Zátor, Brantice, Krnov, ÃÂvalno, Brumovice, Holasovice, Opava, Velké Hoà ¡tice, Kravaà Âe, à  tÃÂtina, Mokré Lazce, Háj ve Slezsku, DolnàBeneà ¡ov, Kozmice, Dobroslavice, DÃÂhylov, HluÃÂÃÂn and Ostrava.
In the section between Krnov and Opava, where the river forms most of the Czech-Polish state border, the river flows along the territory of Gmina Branice.
There are no reservoirs and fishponds built directly on the Opava. There are 754 bodies of water in the basin area. The largest of them is the Slezská Harta Reservoir with an area of .
Common fish in the river include river trout, grayling and common barbel. Among the protected species of fish and lampreys are the common minnow, European bullhead, alpine bullhead and brook lamprey, occurring on the upper course of the river. Among the protected animal species occurring in the lower course of the river are the European crayfish, painter's mussel, swollen river mussel and duck mussel. The entire course of the river is also a nesting and hunting ground for the common kingfisher.
The Opava is suitable for river tourism. The most popular part is the lower section of the river from Kravaà Âe to Ostrava with a length of about , which is passable all year round and is suitable for less experienced paddlers.