A national in situ soil moisture measurement network for Switzerland

The latest Swiss hydrological scenarios predict more frequent and longer-lasting droughts. The Federal Council has just commissioned the establishment of a national drought monitoring and forecasting system based on an integrative approach using in situ, satellite and modeled data. A key element is the installation of a national near-real time in situ soil moisture network that will transfer existing research networks into a long-term secured operational service with homogenized quality control. Where necessary, new additional sites shall enhance spatial representativity.

In addition to drought monitoring, the collected data should also be suitable for use in numerous other applications. The network shall consist of about 30 grassland and forest stations distributed throughout Switzerland. The grassland stations will be exclusively collocated with existing meteorological stations. A good link to the existing Swiss irrigation network with a large number of soil moisture measurements in cultivated fields will be ensured. 

In order to capture the soil water characteristics curve as well as possible, continuous measurements of both volumetric soil moisture and water potential are planned. In addition, auxiliary soil parameters essential for process understanding and modeling will be collected throughout the soil profiles at each site.

Currently, technical implementation issues are being addressed and the soils from a pre-defined set of potential sites are being pre-sampled by the Swiss Competence Center on Soils in order to assess their quality as national sites. The installation phase is scheduled to begin in spring 2024 at the latest and be completed by the end of 2025.

In this contribution the project and its current status will be detailed.