Stream gaging by continuous injection of tracer elements

The practical application of the use of fluorescent-dye tracer elements as a means of determining stream discharge was the consideration of this study. Although this approach is not new in principle, recent developments in fluorometry and the development of new and less expensive fluorescent dyes warrant reappraisal of the method, During this study, the proper use of the fluorometer was mastered, properties of the dye were examined by laboratory tests, and four field tests were conducted. Three of the field tests allowed direct comparison between discharge computed by the dye-dilution method and discharge measured by a current meter; the maximum variation between the results of these tests was 11 percent. The dye-dilution method may be used on streams in the Southwest for high-water measurements of flow above wading stage where no cableway is present or where no adequate current-meter measurement section can be found. The possibility of future automation of this measurement system holds promise for the rating of new gaging stations and for providing streamflow records in remote areas.hydrology collectio