Slovenian hidrogeologic tracer tests inventory

Tracing with artificial tracers is a research method that gives very good results in examining the direction and characteristics of groundwater flow in karst aquifers. The first mention of such experiments in Slovenian karst dates back to history and the beginnings of their use in the water resources management process in the first years of the 20th century. From that point on, more than two hundred tracer tests were carried out in Slovenian karst. Unfortunately, their results often remain hidden in internal reports in the archives of implementing organisations and are very difficult to access. The search for published results is also a time-consuming process, despite the possibilities of the use of search engines and key words. Due to the need for a systematic and rapidly accessible digital inventory of the tracer tests results, such inventory was designed and is now freely accessible in the Environmental Atlas (Atlas okolja: http://gis.arso.gov.si/atlasokolja/profile.aspx?id=Atlas_Okolja_AXL@Arso), the spatial information system of Slovenian Environment Agency. The results of 235 available tracer tests, performed between 1905 and 2021, have been assembled, arranged and georeferenced. The inventory of the geospatial database contains 36 different pieces of data for each tracing that have been compiled using geographic information system tools. The thorough collection of available data includes data on the date, location and details of implementation of the tracer test and on the identified groundwater flow characteristics. Also available are the sources of the published or unpublished reports from which the data were taken. The database includes a comment on the tracer test implementation or results. The inventory is very useful in the process of the integrated management of karst water sources, and especially as an early-warning and monitoring system tool in cases where there is an imminent danger of pollution, which requires a fast and accurate response.