Oder

The Oder ( ; Czech and ) is a river in Central Europe. It is Poland's second-longest river and third-longest within its borders after the Vistula and its largest tributary the Warta. The Oder rises in the Czech Republic and flows through western Poland, later forming of the border between Poland and Germany as part of the Oder–Neisse line. The river ultimately flows into the Szczecin Lagoon north of Szczecin and then into three branches (the Dziwna, Świna and Peene) that empty into the Bay of Pomerania of the Baltic Sea.

The Oder ( ; Czech and ) is a river in Central Europe. It is Poland's second-longest river and third-longest within its borders after the Vistula and its largest tributary the Warta. The Oder rises in the Czech Republic and flows through western Poland, later forming of the border between Poland and Germany as part of the Oder–Neisse line. The river ultimately flows into the Szczecin Lagoon north of Szczecin and then into three branches (the Dziwna, Świna and Peene) that empty into the Bay of Pomerania of the Baltic Sea. ===Main tributaries=== The longest tributaries of the Oder are: ===Canals and waterway modifications=== The Finow Canal, first built in 1605, connects the Oder and Havel. After the completion of the more straight Oder – Havel Canal in 1914, its economic relevance decreased. The earliest important undertaking to modify the river to improve navigation was initiated by Frederick the Great, who recommended diverting the river into a new and straight channel in the swampy tract known as Oderbruch near Küstrin (Kostrzyn nad Odrą). The work was carried out in the years 1746–53, a large tract of marshland being brought under cultivation, a considerable detour cut off and the mainstream successfully confined to a canal. In the late 19th century, three additional alterations were made to the waterway: The canalization of the mainstream at Breslau (Wrocław), and from the confluence of the Glatzer Neisse to the mouth of the Klodnitz Canal (Kłodnica Canal), a distance of over . These engineering works were completed in 1896. In 1887–1891 the Oder–Spree Canal was made to connect the two rivers. The deepening and regulation of the mouth and lower course of the stream. , Poland, flows along the banks of the Old Town and the Ducal Castle]] ===Conditions in the Treaty of Versailles=== By the Treaty of Versailles, navigation on the Oder became subject to International Commission of the Oder. Following the articles 363 and 364 of the Treaty Czechoslovakia was entitled to lease in Stettin (now Szczecin) its own section in the harbor, then called Tschechoslowakische Zone im Hafen Stettin. The contract of lease between Czechoslovakia and Germany, and supervised by the United Kingdom, was signed on 16 February 1929, and would end in 2028. However, after 1945, Czechoslovakia did not regain this legal position, de facto abolished in 1938–39. ===1943 Border with Germany=== At the 1943 Tehran Conference the Allies decided that the new eastern border of Germany would run along the Oder. After World War II, the former German areas east of the Oder and the Lusatian Neisse passed to Poland by decision of the victorious Allies at the Potsdam Conference (at the insistence of the Soviets). As a result, the so-called Oder–Neisse line formed the border between the Soviet occupation zone (from 1949¹ East Germany) and Poland. The final border between Germany and Poland was to be determined at a future peace conference. A part of the German population east of these two rivers was evacuated by the Nazis during the war or fled from the approaching Red Army. After the war, the remaining 8 million Germans were expelled from these territories by the Polish and Soviet administrations. East Germany confirmed the border with Poland under Soviet pressure in the Treaty of Zgorzelec in 1950. West Germany, after a period of refusal, confirmed the inviolability of the border in 1970 in the Treaty of Warsaw. In 1990 newly reunified Germany and the Republic of Poland signed a treaty recognizing the Oder–Neisse line as their border. ===2022 environmental disaster=== On 11 August 2022, it was discovered that the Oder river had been contaminated and at least 135 tonnes of dead fish washed up on its shores. Water samples taken on 28 July indicated possible mesitylene contamination, although the toxin was not present in samples taken after 1 August. ==Notes== ==References== ==External links== multilingual information site on the Oder Odra electronic shipping guide Bibliography on Water Resources and International Law Peace Palace Library

Text derived from https://en.wikipedia.org/w/index.php?oldid=1367738488 under CC BY-SA 4.0; modifications have been made.