The blue-green city
Six percent of Oslo's area consists of freshwater, and the city's ten waterways are an important part of the capital's identity. 354 kilometers of rivers and streams wind through the city. They are not only important recreational areas for the people living in the city, but they are also home to a large number of species of flora and fauna both in and along the water.
Until the 1990s, Oslo's rivers and streams were covered and buried in order to transport polluted water, and to make it easier to build an ever-expanding city. Waterways were closed inside pipes and largely disappeared from the city's surface. By laying rivers and streams in pipes, the polluted water was covered and transported away from the urban areas.
In this way, land became available for the development of housing, schools and business activities. At the same time, however, much of the waterways' unique importance for Oslo's bio diversity, water management and public health disappeared.
From pipes to open waterways
By the end of the 1990s, the trend reversed. Today, it is a political goal to reopen most of Oslo's closed streams and rivers in order to adapt against climate change with heavier and more frequent rainfall, but also to make Oslo an attractive, blue-green city.
Despite ambitious goals, almost 70 percent of Oslo streams and rivers are still covered. In essence, these are smaller creeks and side streams. Of the larger rivers, about 30 percent enclosed. From the 1990s to today, over 3000 meters of Oslo's waterways are reopened.
Adapting to climate change
Enclosed rivers and streams have a limited capacity to handle large amounts of water. Open waterways, on the other hand, have greater capacity to handle increased and more intensive rainfall. Preventing floods is one of the main reasons for the ambitious plan to open Oslo's waterways.
Reopening rivers today is an integral part of a major plan for climate change adaptation in the municipality.
The City of Oslo aims to open waterways in a way that takes into consideration the original nature of the area. In addition, the waterway should, if possible, be placed in its historical run and be accessible for the general public. In this way, the reopening of waterways does not only contribute to better climate adaptation, but also to increased biodiversity, better water quality, and a better air quality for the population.
During the last decade, almost three kilometers of Oslo's waterways have been reopened. In 2017 alone, 550 meters of waterways reemerged.
In recent years, there has been focus on reopening Hovinbekken, from the Økern area, down towards Ensjø and through Jordal. The efforts to open Hovinbekken at Jordal starts in 2019 and the result will be about a 400-meter reopened stream.
Most activity in these projects takes place when new urban development work is underway, which makes land available. The process of reopening streams and rivers is therefore a long-term work, which may take a long time, from the first plans of the reopening itself. An example of this is Gaustadbekken which will be reopened in 2022. Already in 2002, the first plans and ideas were developed.
About another 30 stretches can be reopened. These are investigated more closely in connection with urban development plans, through a systematic work several municipal agencies participate in.
The Teglverk Pond was a major reopening project completed in August 2015. About 650 meters of the Hovin Basin was opened in this project.
The pond is planned and designed as a natural water cleaning system, with several sedimentation pools, several water streams, a small lake and shallow water with dense vegetation. All the species found here are native to Oslo. The result of the project is clean water, increased biodiversity and a popular recreational area for the local population.
These are the ten most important waterways in Oslo