InfoTracer is the FOEN tool to coordinate, centralise and archive information on tracer tests performed in Swiss groundwater and surface water.
Tracer testing is one of the main techniques used in applied hydrogeology; it involves adding a labelling agent (tracer) to water which remains detectable even when heavily diluted. This allows water flow patterns in the subsurface and the exchange between groundwater and surface water to be traced. Tracers are also used to measure the amount of surface water discharge and to monitor infrastructure such as water and wastewater pipes.
InfoTracer – purpose
Tracer testing involves the deliberate introduction of artificial or natural substances into the water cycle. This must be done very carefully. The InfoTracer coordination centre makes available all information regarding the reported use of tracers. The impact of tracer tests can be minimised by:
- avoiding the overlapping use of tracers in the same region;
- ensuring the competent cantonal authorities are informed and that they can coordinate with the body conducting the tracer test if necessary;
- making the metadata on reported tests available centrally for later access;
- providing information on the correct use of tracers in groundwater and surface water.
The system works best when all those involved actively participate. No fee is charged for recording a tracer test.
Use of tracers
Use of tracers
InfoTracer is an information centre for the correct use of tracers. Practical guidelines on the application of artificial tracers in hydrogeology provide an overview of the requirements for planning, carrying out and evaluating tracer tests. The choice of tracer and the quantity used depend on the test object and the test set-up. Care should be taken when selecting a tracer and determining the amount used. Tracer tests should ideally be conducted in accordance with the guidelines.
Reporting tracer tests
Those responsible for the use of tracers (private consultancies, research institutes, authorities, etc.) are requested to report any tests to InfoTracer at least two weeks before they are conducted.
This concerns:
- Tracer tests in groundwater
- Discharge measurements in surface waters
- Testing of infrastructure
Tracer tests can be reported using the online form:
eGovernment Portal UVEK - InfoTracer
-> InfoTracer - Markierversuche melden
The FOEN checks the information submitted and contacts the entity conducting the test if necessary. Once the information has been checked and found to be complete, the FOEN sends confirmation to the conducting entity and to the competent cantonal authority.
Contact:
Tracer tests in Switzerland
Since InfoTracer was launched in 1984, around 13,000 tracer tests have been reported and recorded in the database. Approximately 300 of these are to test groundwater flow paths, and a quarter of these are made directly into the groundwater. The majority of tracers are entered into the unsaturated zone or into surface waters which potentially interact with groundwater. To avoid any overlapping, tracers tests conducted on infrastructure (water pipes etc.) must also be reported.
Tracer tests archived in InfoTracer
Map of archived tracer tests on map.geo.admin.ch
Further information
Last modification 21.03.2025
Contact
InfoTracer
Coordination centre for groundwater tracer tests
Federal Office for the Environment FOEN
Hydrogeological Basics Section