The Göta älv is a river that drains lake Vänern into Kattegat, and the North Sea, at the city of Gothenburg on the western coast of Sweden. It is located in Götaland, with the river itself being a site of early Geatish settlement. The length is 93 km. Often the combination of Göta älv and Klarälven (a river ending at Vänern) is mentioned. This combination is the longest river in the Nordic countries, 750 km . The Bohus Fortress is located by the river at Kungälv. Here the river splits into two, with the northern part being the Nordre älv and the southern part keeping the name Göta älv.
At Trollhättan there is a dam, canal locks and a hydropower station in the river. The locks make the river navigable, even for large cargo vessels (88 m long). The artificial parts are called Trollhätte Canal. The river and the canal is part of a mostly inland waterway, Göta Canal, all the way to Stockholm.
The power station supplied electric power to the heavy steel industry concentrated around Trollhättan, contributing to its industrial revolution. In the summer months the spillway of the dam is opened for a few minutes daily and tourists gather to see the water rushing down the river (picture).