USE OF DEUTERATED WATER AS ACONSERVATIVE ARTIFICIAL TRACER IN THESTUDY OF WATER MOVEMENT IN A COARSEGRAVEL UNSATURATED ZONE

摘要

The processes in a coarse gravel unsaturated zone develop quite differentlyfrom those in aquifers with finer unsaturated zone granulation. The aim of a tracingexperiment using a lysimeter in the Selni?ka Dobrava aquifer was to describe thetransport processes in a highly permeable coarse gravel unsaturated zone. A combinedtracing experiment was performed using both deuterated water and uranine. Deuteratedwater is known as an effective conservative tracer in hydrogeological studies, butonly few studies have focused on the unsaturated zone. Due to its highest degree ofconservativeness deuterium was chosen to study water movement, while uranine withits sorption capacity was used as a contaminant transport indicator. Based on the tracingexperiment’s results, the fastest and dominant flow velocities were estimated. Mean flowvelocity and vertical dispersion were assessed by an analytical best-fit method usingone-dimensional convection-dispersion-model. Deuterium was confirmed as an idealconservative tracer and a more suitable tracer than dye (uranine) for the study of waterflow in the unsaturated zone of a coarse gravel aquifer.