Department Water Resources and Drinking Water

NADUF – National long-term surveillance of Swiss rivers

Sampling station Rheinsfelden at river Glatt

The “National Long-term Surveillance of Swiss Rivers” (NADUF) program was initiated in 1972 as a cooperative project between three institutes: the Federal Office for the Environment (BAFU), the Swiss Federal Institute of Aquatic Science and Technology (EAWAG) and since 2003 the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL).
With the NADUF program, the chemical-physical state of Swiss rivers as well as intermediate-term and long-term changes in concentration are observed. Furthermore, it provides data for scientific studies on biological, chemical and physical processes in river water. The NADUF network serves as a basic data and sampling facility to evaluate the effectiveness of water protection measures and for various scientific projects.

Detailed informations

On the following pages you will find further information concerning the project NADUF.

Map of the NADUF sampling stations (updated 2019)


Legal basis

These data are for information purposes only. They are not binding for legal purposes. Expert advice is necessary for proper assessment. The NADUF group cannot be held responsible for the comprehensiveness or the correctness of the published data. The NADUF group is authorized to change, delete or complete parts of the data or even the entire data set without prior notification or no longer publish temporarily or permanently.
The user of these data accepts that their use is at one's own risk and that neither the NADUF group nor BAFU, EAWAG, WSL can be made liable in case of direct or indirect damage. The following published data may not be used without reference.

Format and Structure of the Data


The excel files are created with the PC dataformat and consist of 8 sheets:

  1. "Rechtsgrundlagen" = Legal Basis
  2. "Bemerkungen" = remarks on special events
  3. "Logsheet" = All editing of the data file
  4. "Konzentrationen_2W" = concentrations in a two-weekly rhythm.
  5. "Sammelprobe K": Sampling usually took place every two weeks (14 days), with the following exceptions:

    • Until 1980, samples of all stations where collected in a weekly interval, at Thur-Andelfingen until 1988.
    • During flood events samples were collected at shorter intervals at some stations.
    • Samples were sometimes taken less frequently due to problems with the sampling equipment.
    • After 2010 samples of small rivers are collected  in a weekly interval

Translation Help

Data files and identification of the samples

The data files contain a sheet with the analyzed concentration in a 14 days rhythm and in the original rhythm.

  • Abbreviation: Every station is labeled with an two letter abbreviation.
  • Year, date, time (indicating the end of the sampling)
  • Status: gives information about the quality of sampling taking, sample handling, the physical data and the chemical data

    • 0 no sample
    • 1 everything ok
    • 2 sample taking slightly disturbed
    • 3 sample taking heavily disturbed, interruption over more the 25% of time
    • 4 chemical data not completely reliable
    • 5 chemical data obviously wrong
    • 6 physical data not completely reliable
    • 7 physical data need to be approved by BAFU
    • 8 not enough sample quantity
    • 9 sample handling not correct
    • 10 no or incomplete sample check list
    • 11 changed rhythm
    • 12 calculation over two weeks is missing

  • Bemerkung: details concerning sample


The data files are regularly updated. Details on the changes and file versions are available from Ursula Schoenenberger.
The Version File provides informations about changes in the dataset or useful remarks about the existing data.


  •  Units
  • Total nitrogen (1974-1986) was calculated from kjeldahl-nitrogen + nitrite + nitrate.
  • If total nitrogen (after 2000) is below limit of determination the value is risen to the value of nitrate if this over 0.25 mg N/l.
  • Hg-samples were collected only over one of two weeks. (italic).
  • Annual average:

    • physical data are calculated arithmetically
    • all other data are calculated proportionally to time and discharge.
    • at least 80% of samples must be measured and over the limit of determination
    • Because the year 1999 has many gaps for x/y plots the annual averages of discharge should be calculated individually for every parameter.

  • Samples:

    • chemical data: at least 75% of the collecting time must be coverd by the sample
    • physical data: at least 50% of the time must be covered.

  • Brugg: from 2008 on the samples were analysed in the lab of AUE (Basel).
  • Rekingen and Weil: from 2002 on heavy metals were measured in the lab of AUE (Basel).
  • Alpthaldaten: Vogelbach from 20.6. to 30.9.2007: in this period no data for mean discharge and water temperature was available. The published data are generated by regression (for more details see the File of the station).

NADUF on Google Earth

Google Earth is a virtual globe, map and geographical information program that can be freely downloaded  via The two files  (NADUF.e.kml und Catchment.kmz) can be downloaded (Folder in ZIP-format) to the desktop and opened with Google Earth.

NADUF.e.kml: This file shows the position of the station. By clicking on a map-pin you get an information window with details of the station, river and catchment area:

coordinations, altitude
mean discharge, river length
area, average altitude, average precipitation, average terrain slope, average terrain aspect, number of inhabitants, landuse, region, typ of landscape, geology, geotechnics
information to discharge, temperature and chemical parameters (arithmetical mean over the whole time of sample collection, interval and numbers of samples)

Catchment.kmz: This file generates the borders (lilac) of the according catchment area on the Google Eath globe. The choice is made in the left-hand window in "Temporary Places" under EZG.

The presentation of the catchment areas is consuming much processing power, therefor the presentation of several catchment areas at the same time might slow down Google Earth considerably.
Due to the reduction to only two dimension large catchment areas can not be presented without slight deformation.
Small catchment areas are visible only when zoomed into the corresponding region.


Download: NADUF_GoogleEarth (This is a Folder in ZIP-Format. If not automatically extracted after downloading do it manuelly.)