1000 measurements undertaken by citizen scientists provide a detailed picture of the water quality in Amsterdam

This summer the water quality in Amsterdam was measured for the first time by citizen scientists, without whom it would not have been possible to obtain such a comprehensive and detailed picture of the water quality in Amsterdam. The Gaasperplas came out on top: the water appears clean, smells good, there are many plants and animals present and there were only low levels of E.coli bacteria. These and many other results will be presented on the evening of Friday 6 October at the Waternet head office during the concluding meeting of The Clean Water Experiment (Het Schone Waterexperiment). The project is an initiative of Deltares, Wageningen University, KWR, Waternet, Amstel, Gooi and Vecht Water Board, AMS Institute and artist Pavèl van Houten.

A number of important and remarkable results:

  • The cleanest water is in the Gaasperplas.
  • The highest E.coli level was measured in the Erasmuspark, which is probably due to duck excrement or an incorrect measurement. This is still being investigated.
  • The temperature of the water in July was so high (almost 23 degrees) that some participants thought the thermometer was faulty.
  • 14 kingfishers were seen; a number of years ago they were a rare sight.
  • According to the residents of Amsterdam half of the water is suitable for swimming.
  • 1000 measurements were undertaken.
  • On average, the water transparency was 83 centimetres, but in the IJ, the Entrepothaven and the Gaasperplas it was a few metres.
  • After the measurements the residents of Amsterdam gave the water a higher score than before the measurements.
  • Three-quarters of the residents of Amsterdam felt more connected with the water as a result of the measurements.
  • In some parts of the city the water often tastes salty, often it has no taste, sometimes it tastes of iced tea or clay and it smells like ‘a forest’.

Study report

The results will be analysed over the coming months and published in a study report. The experiment concludes on Friday 6 October and the provisional results will be presented that evening. Anyone who is interested is welcome to attend.

Citizen science

This is the first time in the Netherlands that citizen scientists have been used on this scale for measuring water quality. The initial feedback is that the project has been successful and has great potential. Detailed and comprehensive measurements have been undertaken. The citizen scientists took their task seriously. A great deal of data has been inputted, the vast majority of which appears to be reliable. Not everything went to plan; of the 500 residents of Amsterdam who registered to take part just over half of them actively undertook measurements in the city and inputted data online. And for the E.coli measurement the wrong bacteria were sometimes counted or too much or too little water was added to the Petri dish, which meant the result was incorrect. The initiators conclude that a great deal was achieved due to the enthusiasm and engagement of the participants.