The Toppila harbour survived as a harbour until the 1960's. A channel six metres deep led to Toppila harbour, while Oulunselkä offered anchorage for ships needing even more draught. The strait had originated when a flood had been searching its way out, growing from a ditch into an important harbour. Up until 1901, tar had been shipped there for the world's needs. It is currently being planned that the Toppila area will become a residential area.