Söderström (Stockholm)

The Söderström (literally "South Stream") is a short, but significant, waterway in Stockholm, Sweden. It connects Lake Mälaren with the Baltic Sea. It runs south of Gamla Stan (the Old Town) and Riddarholmen island. The Söderström, along with the Norrström (North Stream), controls the drainage of Lake Mälaren into the Baltic Sea and plays a vital role in the city's water management. Its course is heavily engineered and regulated.

The flow rate in the Söderström is carefully managed to prevent both flooding in Lake Mälaren and saltwater intrusion into the lake, which would negatively impact the freshwater source. Control structures, including locks and dams, are present to regulate the water flow.

The area around Söderström is historically important and features various bridges, quays, and buildings of architectural and cultural significance. Its banks have been integral to Stockholm's development as a trading and shipping hub. It remains a key element of the city's infrastructure and landscape.