Author(s): Pawel M. Rowinski; Ian Guymer; Andrzej Bielonko; Jaroslaw J. Napiorkowski; Jonathan Pearson; Adam Piotrowski
Keywords: Tracer experiments; Natural rivers; Water velocity measurements; Longitudinal dispersion
Abstract: Large scale tracer test along 90 km river reach was performed in a natural river in the North-East of Poland – Narew River. It was a crucial method for the evaluation of the impact of the retention reservoir on the protected areas of the river downstream and for the evaluation of the threats caused by potential catastrophic releases of toxic substances to that river. The study consisted of the detailed recognition of hydrological and morphometric state within the river channel and actual tracer test. At the crucial cross-sections, streamwise velocities were measured and volumetric flow rates evaluated. The response to the slug injection of a soluble tracer is assumed to imitate the characteristics of a soluble pollutant, so understanding of how tracers mix and disperse in a stream is essential to understanding the processes of pollution transport. The procedure applied during this experiment consisted of the instantaneous injection of a known quantity of Rhodamine WT into the stream and the observation of the variation in concentration of the tracer as it moved downstream.