Indicator water

78% of monitoring stations for nitrate and 70% for phosphate are in good or very good condition. Targets are however being exceeded locally in agricultural and developed regions (see map). Problems occur mainly in small streams with a high wastewater content or a high proportion of intensive farming in the catchment. These small watercourses are covered by the NAWA monitoring network.

The fluctuations between years are due to normal fluctuations in the runoff conditions rather than to a change in the pollution situation. As no significant improvement is observed between 2011 and 2020, the evolution of nutrients in watercourses is considered unsatisfactory.

Nevertheless long term time series do indicate that in general water pollution by nutrients has fallen significantly in the last few decades. The reduction in phosphorus content was particularly evident following the ban on phosphates in detergents in 1986. The phosphorus content continued to fall after 1990 due to the progressive expansion of wastewater treatment plants. Efforts in agriculture to reduce diffuse nitrate and phosphorus discharges, e.g. by less nutrient-intensive soil management and WWTP optimisation can contribute to a further reduction in nutrient concentrations in the water.

• Related indicators
• Biological status of surface waters
• Connection rate to wastewater treatment plants
• Exportierte Stickstoff-Fracht
• Organically farmed area
• Surface water pollution by wastewater

The water quality is recorded jointly by the federal government and the cantons under the NAWA National Surface Water Quality Monitoring at approximately 120 monitoring stations. The chemical state of the water is evaluated on the basis of the phosphate and nitrate concentration by the method “Physico-chemical surveys, nutrients” in the modular stepwise procedure.

For the parameter "Nitrate"

For the parameter "Phosphate"