water tracing

   Underground drainage links through unexplored caves confirmed by labeling input water and identifying it at points downstream. The common labeling techniques involve the use of fluorescent dyes (fluorescein, rhodamine, leucophor, pyranine etc.), lycopodium spores, or chemicals such as common salt. Detection of dye downstream may be purely visual, but if the dye is used at a subvisible (environmentally acceptable) dilution, suitable detectors must be placed in all potential risings and collected for subsequent fluorometric examination (although water samples are more desirable and beneficial). Lycopodium spores are usually collected in fine nets, along with other stream-borne sediment, and must then be identified under the microscope. If chemical tracers are used, regular water samples must be collected for subsequent analysis, or the resurgent waters must be monitored with suitable electronic detectors and recorders. Flowpaths can also be confirmed by transmission of artificial or natural flood pulses, which provide additional data on the nature of conduits, as a pulse is transmitted instantaneously through flooded passages. The longest successful water trace was from Beysehir Golu to the Manavgat springs, in Turkey, over a distance of 130km; 390kg of fluorescein was used and the dye reappeared after 366 days [9].