The Ostravice (, ) is a river in the Czech Republic, a right tributary of the Oder River. It flows through the Moravian-Silesian Region. It is formed by the confluence of the BÃÂlá Ostravice and ÃÂerná Ostravice streams. Together with the BÃÂlá Ostravice, which is its main source, the Ostravice is long. Without the BÃÂlá Ostravice, it is long.
The name is derived from the Czech word ostrá (literally 'sharp', but here figuratively meaning 'fast flowing'). The river was initially called Ostrá. The city of Ostrava was named after the river.
The sources of the river are called BÃÂlá Ostravice ('white Ostravice') and ÃÂerná Ostravice ('black Ostravice'). The colours in the names of the rivers most often appeared according to the nature of the river bed (white = stony river bed, black = muddy river bed).
From a water management point of view, the Ostravice and BÃÂlá Ostravice are two different rivers with separate numbering of river kilometres. In a broader point of view, the Ostravice (as BÃÂlá Ostravice) originates in the territory of BÃÂlá on the border between the Hostýn-VsetÃÂn Mountains and Moravian-Silesian Beskids at an elevation of and flows to Ostrava, where it enters the Oder River at an elevation of . It is long. Its drainage basin has an area of . The name Ostravice is used from the confluence of the BÃÂlá Ostravice with the ÃÂerná Ostravice on the municipal border of BÃÂlá and from this point to the confluence with the Oder, the river is long.
The sources and longest tributaries of the Ostravice are:
The largest settlement on the river is the city of Ostrava. The river flows through the municipal territories of BÃÂlá, Staré Hamry, Ostravice, Frýdlant nad OstravicÃÂ, Prà ¾no, Baà ¡ka, Staré MÃÂsto, Frýdek-MÃÂstek, Sviadnov, à ½abeà Â, Paskov, à Âepià ¡tÃÂ, Vratimov and Ostrava.
In terms of natural regions, the river flows through the Moravian-Silesian Beskids, Moravian-Silesian Foothills and Ostrava Basin. The BÃÂlá Ostravice springs in the area of the Hostýn-VsetÃÂn Mountains, but immediately leaves this region.
There are 598 bodies of water in the basin area. The largest of them is the à  ance Reservoir with an area of , built on the Ostravice. It was built in 1964âÂÂ1969 and its primary purpose is to supply Ostrava and its surroundings with drinking water and protect the area behind the reservoir against floods.
Common species of fish in the river are trout, grayling and common barbel. Among the protected animal species are the common minnow, burbot, European bullhead, alpine bullhead and brook lamprey. The river is a nesting place for the common kingfisher. The Eurasian otter rarely occurs on the middle course of the river.
The Ostravice partly formed the border between historical lands of Moravia (left bank) and Cieszyn Silesia (right bank). It was first agreed as such in 1261 by a special treaty between Duke Wà Âadysà Âaw Opolski and King Ottokar II. Later it was confirmed on 2 August 1297 between Duke Mieszko I and DÃÂtà Âich, bishop of Olomouc. It lost importance as a state border in 1327, when the Duchy of Teschen became a fee of the Kingdom of Bohemia.
Before the construction of reservoirs in the basin, the Ostravice was one of the most fluctuating rivers in the Czech Republic in terms of flow, and its high peak flows in combination with the relief were the cause of catastrophic floods. Among the worst floods were those in 1902 and 1903, and after them came a period of gradual flow regulation, culminating in the construction of the à  ance Reservoir on the Ostravice, à ½ermanice Reservoir on the LuÃÂina, Morávka Reservoir on the Morávka and Oleà ¡ná Reservoir onn the Oleà ¡ná.
The Ostravice is suitable for river tourism only when water is released from à  ance Reservoir, which is once or twice a year. About of the river is navigable.