The Federal Office for the Environment (FOEN) operates a nationwide hydrological monitoring network comprising 260 monitoring stations on rivers and lakes. Groundwater levels and spring discharge are measured at a further 70 monitoring sites. Automated, continuous measurement series are generated at these monitoring stations. In addition, water quality is monitored in accordance with defined sampling plans. Quantitative data are automatically collected at the monitoring stations and fed into WISKI via the data retrieval centre (AZ). The purpose of this procurement is to evaluate a tenderer capable of newly implementing, configuring and further developing the new HydroSys system – for the collection, validation and storage of Switzerland's hydrological data – in accordance with the technical, organisational and functional requirements, on the basis of standard software, and of ensuring its operation, maintenance and support.