As in many other cities, the former dominating strategy for Oslo’s rivers and streams was to enclose them for practical reasons. This approach has changed and the City is actively reopening waterways to make them accessible for people, facilitate increased habitat for biodiversity and handle storm water more efficiently.
The City of Oslo is characterized by urban waterways and their tributaries. Up until the 1980s, the waterways were considered problematic for the sewage system and an obstacle for efficient exploitation of land. Hence large sections of waterways were put in culverts. These culverts have predefined capacities that can cause problems if urban flooding cannot cope with these predefined capacities.
The City of Oslo has decided to reopen closed rivers and streams wherever it is possible and expedient. In order to formalise and streamline the municipal cooperation regarding reopening projects, the relevant municipal agencies have, in collaboration, developed a management document that outlines the principles for reopening projects including a list of prioritised projects. The list is updated annually.
The “Teglverksdammen” Project
In August 2015 a large reopening project in Teglverksdammen was completed. Ca. 650 meters of the Hovinbekken stream was reopened for EUR 10 million. Teglverksdammen is planned and designed as a natural cleaning system, with several sedimentation basins, stream with water rapids, a small lake and shallow waters with dense vegetation. As a result, Teglverksdammen cleans water, provides habitat for biodiversity and has become a popular recreation area for people.