Rivers

The map shows the current dryness level of runoff at stations selected for calculating the combined drought index (CDI). The selection of stations is based on criteria such as data availability and size of the catchment area, as well as the influence of dams. The assignment to a dryness level is based on measured or modelled runoff. 

 

Note on uncertainties: Measuring low discharges to assess drought is technically challenging and can be prone to errors. Some of the stations are influenced by dams in the upper reaches. At these stations, changes in discharge do not only represent natural processes.

The model projections show possible developments in the future and are therefore subject to uncertainties. In addition to the resolution of the model, this is due to simplifications that have to be taken into account when creating the model. The artificial influence of watercourses by dams can be an additional significant source of uncertainty in the hydrological forecasts. In addition to the hydrological model, uncertainties in the meteorological forecast are relevant. This applies in particular to forecasts over longer periods.

 

Data basis: Discharge at the stations of the hydrological monitoring network of the Federal Office for the Environment and the Canton of Zurich (Reppisch-Dietikon and Jona-Rüti). For background information see Basic monitoring network: water level and discharge in surface waters. This drought platform shows weekly averages. The temporal development and values of the discharge forecasts on https://www.hydrodaten.admin.ch/ are shown as hourly values and are therefore not comparable.