Analysis of Discharge Fluctuation Using Modified Streamflow Drought Index (SDI) and Standardized Precipitation Index (SPI) in the Upper Nišava River Basin

Abstract

This paper aims to determine discharge fluctuation in two sub-basins of the upstream area of the Nišava River Basin, and peculiarly to inspect high-discharge and low-discharge events. The influence of precipitation on discharge fluctuation was analyzed too. The data from two hydrological and one climatological station for 45 years were used. Modified Streamflow Drought Index (SDI) and Standardized Precipitation Index (SPI) were used to determine hydrologically and meteorologically dry and wet periods. Results showed that in both sub-basins, hydrologically dry and wet periods can be distinguished, but most of the time river stream discharge was in the mild or moderate range. The study showed that two neighboring and similar rivers could have significant differences in discharge fluctuations and that modified standardized SDI and SPI are good indicators that can be used to compare hydrological conditions in different river basins.

Determination of the Intensity of Hydrological and Climatological Drought in the Južna Morava River Sub-Basin

“…In this way, it is possible to compare individual monthly flows in a hydrological year during the research period. The values of SDI in certain periods can show the occurrence of hydrological drought or high flow (Tabari et al, 2013;Đokić et al, 2022).…”

Анализа Протицаја И Вероватноће Појаве Малих И Великих Вода На Злотској Реци

“…The Pearson function of type III was used to create the curves of the high and low water level fractions. There are a number of distribution functions that are used to calculate the probability of the occurrence of low, high and medium water levels, but the Pearson III distribution is mostly used (Гавриловић, 1988;Gao et al, 2019;Ђокић, 2015;Đokić et al, 2015;Милијашевић, 2010, 2014Sun et al, 2018;Chen et al, 2019). This function is suitable for application because it is determined by only two parameters (if the modulus coefficient is excluded) -coefficient of variation and coefficient of asymmetry (Гавриловић, 1988).…”

“…За израду криве честине великих и малих вода коришћена је Pearson функција III типа. Постоји већи број функција расподела које се користе за израчунавање вероватноће појаве малих, великих и средњих вода, али је често у употреби Pearson III расподела (Гавриловић, 1988;Gao et al, 2019;Ђокић, 2015;Đokić et al, 2015;Милијашевић, 2010, 2014Sun et al, 2018;Chen et al, 2019). Ова функција је погодна за примену јер је одређена само са два параметра (ако се изузме модулни коефицијент) -коефицијентом варијације и коефицијентом асиметрије (Гавриловић, 1988).…”