The Oleška is a

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

in the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

, a left

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the Jizera River. It flows through the

Liberec Liberec (; ) is a city in the Czech Republic. It has about 108,000 inhabitants, making it the fifth largest city in the country. It lies on the Lusatian Neisse River, in a basin surrounded by mountains. The city centre is well preserved and is pr ...

and

Hradec Králové Hradec Králové (; ) is a city of the Czech Republic. It has about 94,000 inhabitants. It is the capital of the Hradec Králové Region. The historic centre of Hradec Králové is well preserved and is protected as an Cultural monument (Czech R ...

regions. It is long.

Etymology

The name is derived from the Czech word ''olše'' (i.e. '

alder Alders are trees of the genus ''Alnus'' in the birch family Betulaceae. The genus includes about 35 species of monoecious trees and shrubs, a few reaching a large size, distributed throughout the north temperate zone with a few species ex ...

'), meaning "water flowing between alders".

Characteristic

The Oleška originates in the territory of Studenec in the

Giant Mountains Foothills In folklore, giants (from Ancient Greek: '' gigas'', cognate giga-) are beings of humanoid appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''giant'' is first attested in 1297 from ...

at an elevation of and flows to

Semily Semily (; ) is a town in the Liberec Region of the Czech Republic. It has about 8,000 inhabitants. Administrative division Semily consists of four municipal parts (in brackets population according to the 2021 census): *Semily (2,554) *Bítoucho ...

, where it enters the Jizera River at an elevation of . It is long. Its

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

has an area of . The longest tributaries of the Oleška are:

Course

The river flows through the municipal territories of Studenec,

Levínská Olešnice Levínská Olešnice is a municipality and village in Semily District in the Liberec Region of the Czech Republic. It has about 300 inhabitants. Administrative division Levínská Olešnice consists of two municipal parts (in brackets population a ...

Stará Paka Stará Paka is a municipality and village in Jičín District in the Hradec Králové Region of the Czech Republic. It has about 2,200 inhabitants. Administrative division Stará Paka consists of six municipal parts (in brackets population accordi ...

Bělá Bělá may refer to: Places in the Czech Republic *Bělá (Havlíčkův Brod District), a municipality and village in the Vysočina Region * Bělá (Opava District), a municipality and village in the Moravian-Silesian Region * Bělá (Pelhřimov Di ...

Libštát Libštát () is a market town in Semily District in the Liberec Region of the Czech Republic. It has about 900 inhabitants. Etymology The name was derived from the Middle High German words ''liube stat'', meaning 'nice place'. Geography Libštát ...

Košťálov Košťálov is a municipality and village in Semily District in the Liberec Region of the Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is ...

, Slaná and

Fauna

Fish species that live in the river include

brown trout The brown trout (''Salmo trutta'') is a species of salmonid ray-finned fish and the most widely distributed species of the genus ''Salmo'', endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally ...

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributary, tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout) is an Fish migration#Classification, ...

brook trout The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae native to Eastern North America in the United States and Canada. Two ecological forms of brook trout h ...

and grayling.

References

External links

River flow at Slaná station
– Flood Warning and Forecasting Service of the

Czech Hydrometeorological Institute The Czech Hydrometeorological Institute (CHMI; ) is the central state office of the Czech Republic in the fields of air quality, meteorology, climatology and hydrology. It is an organization established by the Ministry of the Environment of the Cz ...