Author(s): Rajwa A. ; Rowinski P. M. ; Bialik R. J. ; Karpinski M.
Linked Author(s): Robert J. Bialik, Pawel M. Rowinski
Keywords: Dissolved oxygen; Water temperature; Hysteresis
Abstract: The present work aims to discuss results obtained from the field investigation on dissolved oxygen variability carried out on two natural lowland rivers, namely the wider and the Narew belonged to national park and natural reserve. Both of them represent different types of rivers, starting from small, sand bed river with migrating bedforms and relatively low aquatic and riparian vegetation, ending up with the streams represented by substantial canopy cover, plants and bank vegetation. Field measurements, including diel and point measurements of dissolved oxygen, temperature and air pressure aimed to show various characteristics of diurnal dissolved oxygen profiles such as daily amplitudes and maxima. Simultaneously, hydraulic characteristics of the stream and flow properties such as discharge, velocity field in the river cross-section, friction and mean velocity were measured using acoustic Doppler current profiler (ADCP) and acoustic Doppler velocimeter (ADV). Diurnal oxygen profiles juxtaposed with temporal temperature distributions revealed some characteristic phase shift, suggesting hysteretic relationship. Resulting temperature-oxygen hysteresis loop shape was correlated with basic hydraulic characteristics of the stream. Moreover, the results have shown that diurnal profiles of dissolved oxygen vary considerably among streams depending on site characteristics and those differences are analysed in the paper.
Year: 2014