How clean is the water?

the water

The Marineterrein's inner harbour is not yet an official swimming location. However, surveys of the harbour's water quality and efforts to resolve issues have been ongoing for some time now.

the water

The Marineterrein's inner harbour is not yet an official swimming location. However, surveys of the harbour's water quality and efforts to resolve issues have been ongoing for some time now.

  • Short

    Sports, exercise, and games are all part of life on the Marineterrein, and the inner harbour could be a great place to improve your fitness and work on your technique, speed, and stamina. Local residents appear to be avid swimmers, but this is at their own risk, as the harbour has still not been declared an official swimming spot. However, we are doing our best to make sure it will be.

    In order to become an official swimming spot, the area’s water quality must be measured for two years and score consistently well during this time. Although most measurements so far have scored well, some values are too high and indicate that the water still contains too many harmful bacteria. Swimmers who swallow some of that water can suffer from abdominal pain, vomiting, or diarrhoea. How can we improve the situation?

  • Facts

    Survey: In 2016, students on the Tesla Minor at the University of Amsterdam conducted an exploratory survey into the water quality in the Marineterrein’s inner harbour. The water quality was good in three of the four measurements – with one measurement indicating poor quality – according to the standards that are used for an official swimming spot.

    Follow-up survey: In 2017, the Municipality of Amsterdam had Deltares conduct a survey using an AquaScope: an innovative measuring device by the company Biotrack that enables much more precise and frequent monitoring of water quality than standard measuring methods. This survey clearly showed peaks in the number of bacteria in the water immediately after a rainstorm. It was suspected that this was caused by overflows from sewers that sometimes overrun following heavy rainfall.

    New measurement methods: In order to detect the contamination ‘leak’, 2018 saw us join forces with Sanitas Water, Deltares, and Sensemakers to devise and test out smart measuring methods here at the Marineterrein. All the pipes were surveyed to locate the source of pollution, which turned out to be what we had expected: a sewer pipe on the Marineterrein.

    Conclusion: We can say that the water quality in the inland harbour is headed in the right direction. However, it may still be a few years before the inland harbour becomes an official swimming spot, which alongside having good water quality needs to be accessible and safe for users. There is still a great deal of research and changes to be carried out regarding accessibility and safety. So until then, you swim here at your own risk!

  • Info


    The knowledge gathered on new measurement methods and contamination detection is being shared with other municipalities and institutions in order to improve water quality at another locations.

    The surveys were carried out by:

    • Deltares
    • Biotrack
    • Waternet
    • Sanitas Water
    • Sensemakers


    Commissioned by:

    • the Municipality of Amsterdam
    • Bureau Marineterrein Amsterdam

How clean is the water?

  • Download the UVA survey report (English)

    Download de Deltares research report (Dutch)


    What is on the bottom of the harbour?

    The bottom has become contaminated with heavy metals and oil remnants over the centuries. If the bottom is stirred up, these substances can become mixed with the water. This is unlikely to happen as a result of someone swimming, as the bottom of the canal is at a depth of 3 to 4 metres, but it can happen as a result of lots of ships passing through. In the future, the bottom could be covered with a clean layer of sand, so that the contaminated sediment doesn’t get mixed into the water as easily.

    What life is there in the water?

    Marineterrein has been closed off for many years, including for biologists and ecologists. As a result, we know little about the nature on land and in the water. What we do know is that the high stone walls offer little opportunity for water plants and fish to make their homes in. It is beneficial to create alternative habitats in the inner harbour, as a good ecosystem is the best way to promote clear, clean water.