ABSTRACT
Tracing tests must be thoroughly planned and prepared. The extent of the preparations depends upon the nature of the task. Smaller tests over short distances naturally need less preparation time, materials, and accessories than large combined tests. Extensive tracing tests require ample preparation time. A tracing test usually starts with exploratory surveys in the investigation area. The tracing test’s expenditures themselves are normally paid for or provided by the contracting authorities. All tracing tests connote injecting a foreign substance into the water system, which requires an authorization according to the relevant water laws. The proper authorities need to be opportunely informed about planned tracing tests and if required, the application supplied with the necessary reasons. Often the success or failure of a tracing test depends upon the correct type and state of the injection site being chosen. Tracers that tend towards sorption and ion exchange can only be rarely used in channels and aquifers that have large relative surfaces.
