The Tisza River

The Tisza or Tisa is one of the main rivers of Central Europe. It flows for 966 km and drains a river basin of 157,220 km2. It is the largest tributary of the Danube and remains one of Europe’s most natural rivers.

The Tisza rises in Ukraine and is formed near Rakhiv by the junction of White Tisa, whose source is in the Chornohora mountains and Black Tisa, which springs in the Gorgany range. It flows roughly along the Romanian border and enters Hungary at Tiszabecs. Downstream it marks the Slovak-Hungarian border, passes through Hungary, and merges with the Danube in north Serbia.

In Hungary, the length of the Tisza used to be much bigger, adding to a total length of the river of 1419 km. It flowed through the Great Hungarian Plain, which is one of the largest flat areas in Central Europe. Since plains can cause a river to flow very slowly, the Tisza used to follow a path with many curves and turns. In 1846 the so-called "control of the Tisza" began, ending in 1880. The new length of the river in Hungary reduced the total length of the river to 966 km.

The Tisza River got into the global spotlight in the early 2000, when two industrial accidents occurred on its tributaries in north-western Romania. On the evening of 30 January 2000, a tailings pond burst at a facility near the city of Baia Mare, which served for reprocessing old mining tailings and re-depositing the waste sludge. This led to approximately 100,000 m³ of waste water containing up to 120 tonnes of cyanide and heavy metals being released into the Lapus River, then travelling downstream into the Somes and Tisa rivers into Hungary before entering the Danube. At the time the spill was called the worst environmental disaster in Europe since the Chernobyl disaster.