Söderström is a river in central

Stockholm Stockholm (; ) is the Capital city, capital and List of urban areas in Sweden by population, most populous city of Sweden, as well as the List of urban areas in the Nordic countries, largest urban area in the Nordic countries. Approximately ...

that connects Lake Mälaren with the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North European Plain, North and Central European Plain regions. It is the ...

. It runs south of

Gamla stan Gamla Stan (, "The Old Town"), until 1980 officially Staden mellan broarna ("The Town between the Bridges"), is the old town of Stockholm, Sweden. Gamla Stan consists primarily of the island Stadsholmen. Gamla Stan includes the surrounding islets ...

from

Riddarfjärden Riddarfjärden (, "The Knight Firth") is the easternmost bay of Lake Mälaren in central Stockholm. Stockholm was founded in 1252 on an island in the stream where Lake Mälaren (from the west) drains into the Baltic Sea (to the east); today the i ...

to Stockholms ström (the western part of Saltsjön). It is one of two natural waterways between Mälaren and the Baltic sea, the other being

Norrström Norrström is one of the shortest rivers in Europe in central Stockholm. It connects Lake Mälaren with the Baltic Sea. It runs from Riddarfjärden, north of Gamla stan, to Stockholms ström (the western part of Saltsjön). Two islands lie with ...

north of Gamla stan. Centralbron crosses the waterway. The river is locked by Karl Johansslussen (Karl Johan's lock), and most of the time is conceived as more like a bay of Mälaren. The area around the lock is known as the Slussenområdet, and beginning in 2016 is undergoing a major revitalization. The channel of an older lock, known as the Nils Ericson lock, still exists just to the north of Karl Johansslussen. This lock is hidden by the steps leading to Karl Johans Torg, but it still allows for the discharge of water from Mälaren into the Baltic. It is planned to convert the channel of this older lock into a

fish ladder A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon, is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as mov ...

, as the revitalized area will include two much larger discharge channels on either side of the new lock.

References

Geography of Stockholm Mälaren Rivers of Stockholm County Waterways in Sweden {{Stockholm-geo-stub