Trend analysis and time series decomposition on hydrological profile Mojsinje in the Juza Morava River Basin

Abstract

The Juzna Morava basin covers an area of 15,469 km2, its surface area and hydrological peculiarities require constant research. Imbalances of small, medium and large waters, torrential and erosive events are frequent. Average flows are statistically obtained values, which are most often used in practice when analyzing and preparing studies for further monitoring purposes The non-parametric Mann-Kendall test and Sen’s slope estimation were applied for trend observation, and the Pettit test was used to determine the breaking point in the analyzed time series. Data collected on the hydrological profile of Mojsinje (Juzna Morava) in the time interval 1961-2020 were processed The average annual flow (Qavg) is the most important hydrological indicator for observing trends in longer time series; mean monthly and seasonal flows were also analyzed. Based on the applied tests, it was determined that the water level on the hydrological profile decreases (0.70m3/s/year) without statistical significance, while the results obtained for May are the most significant (-2.10m3/s). The breaking point of the average discharges for most of the data series was recorded in the early 1980s (1982–1984), which coincides with the pluviometric regime in the basin. The analysis of seasonal hydrological events in the basin shows negative trends, most significant in winter. In order to determine wet and dry years, they have been classified according to water richness using the SDI index.