Otava (river)
The Otava is a river in the Czech Republic, a left tributary of the Vltava River. It flows through the Plzeň and South Bohemian regions. It is formed by the confluence of the Vydra and Křemelná rivers. Together with the Vydra, which is its main source, the Otava is long, making it the 13th longest river in the country. Without the Vydra, it is long.
Etymology
The origin of the name is unclear. The word otava literally means "second harvest of grass", but the name of the river is probably of pre-Slavic origin and the resemblance to the word otava is only coincidental. A possible but unproven origin is the Germanic word Vatahva, meaning "quick water". According to one theory, the name of the river is derived from the Celtic words áth a ava, which meant "river with many fords".Characteristic
From a water management point of view, the Otava and Vydra are two different rivers with separate numbering of river kilometres. The Otava itself is formed by the confluence of the Vydra and Křemelná in the territory of Hartmanice, and is long. In a broader point of view, the Otava arises in the territory of Modrava in the Bohemian Forest at and flows to Zvíkovské Podhradí, where it enters the Vltava River at an elevation of. It is long, making it the 13th longest river in the country. Its drainage basin has an area of.The Otava has many relatively significant tributaries, the following being the longest ones:
| Tributary | Length | River km | Side |
| Blanice | 94.7 | 32.8 | right |
| Lomnice | 59.3 | 24.9 | left |
| Volyňka | 46.1 | 54.6 | right |
| Ostružná | 41.2 | 88.9 | left |
| Křemelná | 32.9 | 111.7 | left |
| Brložský potok | 27.6 | 35.5 | left |
| Vydra | 23.7 | 111.7 | – |
| Novosedelský potok | 23.5 | 60.5 | right |
| Březový potok | 21.7 | 62.9 | left |
| Volšovka | 19.6 | 94.5 | left |