Water tracing involves tagging water to see where it goes. The time the tracers take to get from one point to the other is also usually recorded. It is most commonly used in karst environments to ascertain groundwater flow rates, directions and catchment definitions (Zone of Contributions).
In 2007, The Geological Survey of Ireland established a database compiling and detailing water tracing experiments carried out in the Republic of Ireland. The primary purpose of creating this database is to serve as an inventory of known water tracing experiments and to store details of the traces. Data are compiled from numerous sources including maps, academic and caving journals, company reports and personal communication. The database contains specific details for each tracing experiment. The database is populated with all known traces.