| Oslava | |
| Source1 Location: | Matějov, Křižanov Highlands |
| Mouth Location: | Jihlava |
| Mouth Coordinates: | 49.0975°N 16.3642°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Czech Republic |
| Subdivision Type2: | Regions |
| Length: | 101.2km (62.9miles) |
| Discharge1 Avg: | 3.47m3/s near estuary |
| Basin Size: | 867km2 |
The Oslava is a river in the Czech Republic, a left tributary of the Jihlava River. It flows through the Vysočina and South Moravian regions. At 101.2km (62.9miles), it is the 24th longest river in the Czech Republic.
The first written mention of the river is from 1146, when it was called Ozlawa in a Latin text.[1] According to one theory, the name is derived from the old Czech word osla, which meant "grind" and referred to the stones suitable for grinding that were found in the river. According to the second theory, the name comes from the Celtic (Gaelic) òs, òsa, meaning "slow flowing water".[2]
The Oslava originates in the territory of Matějov in the Křižanov Highlands at the elevation of and flows to Ivančice, where it enters the Jihlava River at the elevation of . It is 101.2km (62.9miles) long, which makes it the 24th longest river in the Czech Republic. Before the remeasurement, its length was stated as 99.2 km until 2013 and then 99.6 km until 2021. After a survey by hydrologists, the location of the spring was specified according to the most abundant source and the length of the entire river was redefined.[3] Its drainage basin has an area of 867km2.[4]
The longest tributaries of the Oslava are:
| Tributary | Length (km) | River km | Side | |
|---|---|---|---|---|
| Balinka | 31.1 | 60.3 | right | |
| Chvojnice | 20.0 | 17.6 | left | |
| Bohdalovský potok | 17.3 | 83.0 | right |
The largest town on the river is Velké Meziříčí. The river flows through the following settlements: Nové Veselí, Ostrov nad Oslavou, Velké Meziříčí, Náměšť nad Oslavou, Oslavany and Ivančice.
The Mostiště Reservoir is constructed on the river and is the largest body of water in the basin area. A notable body of water is also the Veselský Pond with an area of .[4]
There were recorded 16 species of aquatic molluscs in the Oslava river: 8 species of gastropods and 8 species of bivalves. There lives endangered species of bivalve Unio crassus at the lower river section.[5]
The Oslava is suitable for river tourism. About 88 km of the river is navigable.[6] [7]