DOI: 10.5593/SGEM2016/B31/S12.102


M.Sokac, Y. Veliskova
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-61-2 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 1, 781-788 pp

Paper describes the measurement methodology of tracer field experiments at lowland channel, as well as the obtained results from these measurements and their analysis. During the measurements we found, that there is a large portion of so called dead zones, i.e. zones with transient storage of pollutant (tracer) in the investigated channel reach. These zones significantly distort the measured tracer concentrations time course. The paper deals with determination of dispersion coefficients from mentioned field tracer experiments in a stream with dead zones. The values of these coefficients are specific input data for numerical models simulating the pollution spreading in water environment. In the case of natural streams one-dimensional model is sufficient to obtain indicative values of transported pollution concentrations. Therefore, this paper is focused to the methodology and results for determination of the longitudinal dispersion coefficient.
The measurements, tracer experiments and their evaluation were performed on straight channel reach of the Šúrsky channel, situated close to the village Svätý Jur (Slovakia). The field measurements were made in 50 up to 500 m long straight channel reach with relatively prismatic cross section profile. The channel bed was 4-5,5 m width at water level, max. depth was in the range 0,4 - 0,8 m, velocity 0,21-0,36 m.s-1 and a discharge was 0,38-0,43 m3.s-1. The range of determined longitudinal dispersion coefficient was 0,63 – 0,82 m2.s-1 .

Keywords: dispersion, pollution, surface water, stream, transient storage