LOW-FLOW DISCHARGE DEFICITS ASSESSMENT, APPLYING CONSTANT AND VARIABLE LOW-FLOW THRESHOLD LEVELS, AS ILLUSTRATED WITH THE EXAMPLE OF SELECTED CATCHMENTS IN THE VISTULA RIVER BASIN

Edmund Tomaszewski, University of Łódź
2018 Acta Scientiarum Polonorum. Formatio Circumiectus  
In the present study, we have assessed low-flow discharge deficits, and the characteristics of the low flows at a constant and variable (monthly) low-flow threshold. The low-flow truncation level was identified based on the 70th percentile from the flow duration curve (Q 70% ). Q 95% was assumed to be the threshold for the deep low-flow discharge. Thirteen catchments in the Vistula basin, varying in size, river regime, and physico-geographical conditions, were selected for the study. The input
more » ... e study. The input data was a series of daily discharge data sets from the period 1951-2016, made available by IMGW-PIB (Polish Institute of Meteorology and Water Management -National Research Institute). Analyses were conducted of drought flow discharge deficit volume in absolute and relative values, and low-flow duration and deficits contributing to severe low-flows were calculated for temporal scales of months and years. Comparison of the obtained results led us to the determination of the basic factors affecting the formation of low-flow deficits, and the indication of restrictions when applying fixed and variable criteria for identifying river low-flows.
doi:10.15576/asp.fc/2018.17.3.205 fatcat:6xkokjwj4fhsfibdpv5bz562am