Name of the case study
Description of context
Calculations were made on how many detention basins would be needed. The main pollution in the harbour was coming from storm-water overflows. The pollution from the industries was strongly declining as they were moving out of the harbour (although some pollution was still left in the harbour). Pollution from the detention basins only occurs in times of extreme rainfall, where rainwater is mixed with wastewater from households and led to the local recipient (the harbour). This occurs app. 20 times per year. In most situations, however, the rainwater is kept in the detention basins, and led to the local sewage treatment plant where it is cleansed. The way to avoid such overflows is simply to increase the capacity of the detentions basins. In spite of heavy investment (expected 1 bill. Dkr., or 140 mill. €) for detention basins, it was broadly accepted by the City Council.
According to the Sewage Plan 2000, bathing water quality has to be established in 2009. Although this goal has been reached, detention basins in the rest of the harbour still have to established, due to the political promises made for more bathing sites. The City Council has granted 100 mill. Dkr. (15 mill. €) annually the next couple of years to establish detention basins. However, the basins have to be established along with new buildings at the harbour-front, including the new opera house. Once the opera (or other buildings) are built, it will be impossible to change.
Description of project - background
In the summer of 2001 it became possible to bathe in the inner harbour of Copenhagen. At Islands Brygge a pavilion for public bathing was established by the municipality, and became an instant success with. Thousands of people from Copenhagen and its suburbs were visiting the bath over the summer. It has become one of the (in not the) major environmental successes in Copenhagen due to its very visible and tangible character, which makes environmental progress very understandable. The municipality of Copenhagen has used pictures from the harbour bath intensively to promote the image as a green municipality (for instance as "the environmental capital of Europe").
It was the massive investments in detention basins along the harbour that enabled bathing. By establishing detention basins along the harbour, the overflows of sewage have been reduced from 1.600.000 to 800.000 m3 per year. In the Southern Harbour alone, the overflows have been reduced from 600.000 m3 to 300.000 m3, in overflows corresponding to a reduction from app. 20 to 7-8 per year. Two to four of the overflows take place in the bathing season. An important detail for making bathing practically possible was the establishment of a warning system that warns the bathers about overflows from the detention basins. The warning system consists of censors measuring how much water runs from the detention basins to the harbour (1 time per second). This is logged and sent to Copenhagen Energy, who collects the data and sends it on to DHI (Danish Hydraulic Company, a private company), who puts the data into the MIKE-model of the Copenhagen harbour. This allows fast estimations on whether an overflow makes the water exceed the limits, and the bathing sites should be closed temporarily (a red flag signalises that the water is temporarily polluted and bathing is prohibited). Before the system was installed, control measures were made from different places in the harbour, to be sure that the model was able to calculate the same values as measured in reality.
Copenhagen Energy has the responsibility of establishing detention basins along the harbour.
Description of project - objectives/aims
Description of project - time interval and stages
Description of project - financing
Description of project - other sectors involved
What tools were used to assess sustainability?