Quality surface water, 2015

Interactive chart water quality

Link to the interactive chart water quality where the quality elements and the biological and physico-chemical parameters can be selected.

Evaluation method surface water

The quality of surface water is expressed in the chemical quality and the ecological quality. The ecological quality is predominantly defined by the biological quality, furthermore with the assessment of river basin specific pollutants and the physio-chemical quality. The WFD includes a method to evaluate the quality of surface water:

• Europese Kaderrichtlijn Water

Ecological quality

Throughout the Netherlands, the ecological quality level ranges between moderate and poor, the label 'very good' is not assigned. The biological quality of 34 bodies of water is good, but only 3 of them a good ecological quality. Nitrogen and phosphorus are the components with the highest number of waterbodies that does not meet the standard..

Chemical quality

In nearly half of the bodies of water in the Netherlands, the chemical quality level is adequate. The chemical quality is based on 33 substances or group of substances specified on the European level. This will be increased to 45 substances in 2021.

Main causes

The main causes for the moderate to poor quality of Dutch surface water are:

• high concentrations of persistent substances due to emissions in the past. The evaluation of the chemical condition and the other relevant substances is not sufficient, due to the presence of persistent substances or emissions from the past decades.
• Overfertilization with the nutrients nitrogen and phosphorus. These chemical elements cause algae growth.
• Water management. Most streams have been straightened and the banks leave very little or no room for the natural habitats of plants and animals. The banks of most lakes and channels are armoured with rocks, making it impossible for ecosystems to develop. The water level is nearly always controlled, which limits the dynamics of the natural environment.
• The presence of pumping stations and dams. Fish can hardly migrate. Fish passages are constructed to improve this situation.
• Pesticides cause large-scale death of water flea populations.

The parameters with the highest number that does not meet the standard or a good quality are phosphorus, nitrogen of the physico-chemical quality element, zinc of the river basin specific pollutants and fluoranthene of the chemical status.
In the interactive chart water quality maps of the quality elements and the parameters of the biological and physico-chemical quality are available. The map of the water boards can be selected.