The Odra is a river in Central Europe. It rises in the Czech Republic and flows through Poland, then forms the northern 187 km long border between Poland and Germany. The Oder is an 854 km long river. It is the second longest river in Poland. It drains 118,861 km², of which 106,056 in Poland (89%), 7217 in the Czech Republic (6%) and 5,587 in Germany (5%). Before the flow was regulated, the river was over 1,000 km long.
The course of the flow
In the Czech Republic, the river flows through the Libavá Military Station (where it is mostly inaccessible to the public). Through the town of Odry, through the Czech part of Silesia (Moravian-Silesian Region). In Poland, through the Silesian Voivodeship, Opole Voivodeship, Lower Silesian Voivodeship, Lubusz Voivodeship and West Pomeranian Voivodeship. And in Germany, through Brandenburg and Mecklenburg-Western Pomerania.
After the Oder leaves the mountains, it flows mainly in a wide terraced valley, which widens from 2 to 3 km to 10 to 20 km. This valley was formed by the runoff from the glaciers after the last ice age. Below the mouth of the Lužické Nisa it reaches a width of 200 m. It is a massive stream whose banks are protected by flood defences.
The water regime of the Oder
The Oder reaches its highest flows in spring, especially in March and April. In summer its level drops, but the drop is interspersed with occasional rises due to rainfall. When it is winter, the river’s flow begins to rise continuously. In severe winters the river freezes.
The average flow of the Oder in the lower reaches of the river near the village of Gozdowice, located about 30 km below the confluence with the Warta River, is 547 m³/s.[4] The rise in the upper reaches is 6 to 7 m and in the middle reaches 4 to 5 m. According to the chronicles of Wrocław, major floods on the Oder occurred in 1348, 1464, 1564 and 1903. The largest flood to date occurred in July 1997, when 3640 m³/s flowed through Vratislav.
