National River Monitoring and Survey Programme (NADUF)

The National River Monitoring and Survey Programme (NADUF) tracks the concentrations of substances occurring in selected Swiss watercourses.

NADUF, launched in 1972, is a project run jointly by the FOEN, Eawag (the Swiss Federal Institute of Aquatic Science and Technology) and, since 2003, the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL). 


In accordance with the Environmental Protection Act of 7 October 1983 (Art. 44 para.1) and the Water Protection Act of 24 January 1991 (Art. 57 para. 1) the confederation gave a mandate to survey environmental impacts and to survey, on behalf of pan-Swiss interests, the water quality of surface water courses and groundwater. The programme "National River Monitoring and Survey Programme (NADUF)" responds to a part of this mandate by monitoring the development of the concentrations and load of important substances contained in water in important watercourses.


The programme is designed to provide the fundamental data required for water protection and research. For this purpose, nutrients and pollutants have been studied continuously in large and medium-sized rivers since the mid-1970s and also in smaller watercourses since the beginning of the 2000s.

The findings are used in assessing the effects of existing water protection measures and, where necessary, in planning additional measures.

Measurement programme

Collection of the basic data for target achievement is carried out at selected stations on the national hydrology monitoring network in long-term measurement programmes and project-based surveys. Long-term sampling, combined with accurate discharge measurements, enable accurate determination of pollution levels.

The duration and scope of the monitoring surveys vary according to requirements, scientific interest and practice at the different NADUF stations.

NADUF: Measurement programme 2023 (PDF, 106 kB, 27.01.2023)NADUF station network, duration and scope


The levels for calculating discharge and the water temperature are continuously recorded at all the stations. At most locations the pH value, electrical conductivity and dissolved oxygen are also permanently monitored.

Parameters affected by both geochemical and anthropogenic factors are chemically analysed on 14-day aggregate samples. These are total hardness, alkalinity, calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), chloride (Cl), sulphate (SO4), silicate (H4SiO4), nitrate (NO3), ortho-phosphate (PO4), total phosphorus (Ptot), dissolved organic carbon (DOC), total organic carbon (TOC), until 1986 also nitrite (NO2), ammonium (NH4) and Kjeldahl nitrogen, and since 1987 total nitrogen (Ntot). Some stations also analyse the heavy metals zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), mercury (Hg), chromium (Cr) and nickel (Ni). In the period 1991 to 1998 the variable parameters nitrite and ammonium were analysed at various stations by on-site measurements in separate campaigns lasting several days.

Overview of the NADUF stations

The station descriptions include the following key data: coordinates, station elevation, river length, size of catchment, average areal slope and elevation, average discharge and areal precipitation, specific load (ratio of population numbers to discharge) and a photograph of the immediate environment of the station.


The results of the programme are also incorporated in the Material Balance chapter of the Hydrological Atlas of Switzerland (HADES).

Further information


Increasing chloride concentrations in Lake Constance (PDF, 719 kB, 20.09.2013)characterization of sources and estimation of loads

Water Chemistry of Swiss Alpine Rivers (PDF, 725 kB, 14.06.2010)Zobrist, J. (2010). In: U. Bundi (ed.), Alpine waters

National long-term surveillance of Swiss rivers (PDF, 312 kB, 08.06.2010)Jakob A., Binderheim-Bankay E. and Davis J.S. (2002), Verh. Internat. Verein. Limnol. 28, p 1101-1106

30 Jahre NADUF - Eine Zwischenbilanz (PDF, 6 MB, 23.11.2010)Jakob A., Liechti P. und Binderheim E. Gas - Wasser - Abwasser, 3/2002, S. 203-208.

Other literature references on this subject is listed in the document below. The studies and reports are available on request from the following address:

Last modification 27.01.2023

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