Annual and Seasonal Variations of River Dischargesin the South Morava River Basin (Republic of Serbia)

Abstract

Understanding the current status of wateriness, which include studying the variability of different hydrological parameters over a long period of time, represents a significant process for determining the availability and quantity of water resources, especially at the local and regional level. First, it is necessary to identify certain paternity and frequency in a long time series of hydrological parameters. Secondly, it is important to correlate them with variability of some climatological elements on the one hand and anthropogenic influence in other hand, which are the main factors that have influence on the changes in river wateriness. The main objective of this paper is the analysis of seasonal and annual variations of river discharges in the South Morava river basin, for the period of 50 years , and the observation of certain trends (using non-parametric Mann-Kendall test and homogeneity test). Explanation and understanding the potential causes of observed changes, which are significant, is one of the tasks of this research. In this paper are observed data of the mean annual and monthly river discharges from 20 active hydrological stations in the South Morava river basin, for which there are empirical data for the taken period. The results indicate that most rivers in the basin have dominant decreasing trend of the mean annual river discharges (85% of them), but the more significant changes are noticed for the values of the seasonal river discharges.

Determination of Discharge Cycles of the South Morava River (Serbia)

“…Secondary peaks that are not proportional are greatly influenced by other physical-geographical and especially anthropogenic factors (accumulation construction in the South Morava River Basin, river regulations, water use, etc.). In accordance with the achieved decreasing trend of discharge values on the Mojsinje HS, are the results obtained by other researchers [30], [16]. Langović [16] determined occurrence of decreasing trend at three HS on the Nišava River and its tributaries Temska and Jerma (pronounced and moderate significancy).…”

“…For the purpose of this article, several statistical and quantitative methods, processed in different statistical programs, were used. Before the existence of certain discharge repetition was determined, trends of river discharges were analyzed by using Mann-Kendall and homogeneity tests, which are applied in many meteorological and hydrological analyzes [18], [19], [20], [16], [21]. Autocorrelation is a statistical method also known as "serial correlation".…”

“…Its river valley has composite feature in south to north direction, which indicate appearance of several gorges and valleys. The South Morava River Basin covers an area of 15,469 km2, with smaller parts in the territories of Bulgaria and Northern Macedonia [15], [16]. On the South Morava River six active hydrological stations has been registered.…”

Investigation of the lateral channel migration: A case study of the South Morava River (Serbia)

“…Analyzing by seasons, a slightly increasing trend of river discharge values can be determined only during the spring season (trend value of 0.5), which is an important characteristic, considering that the maximum daily discharge most often occurred during the mentioned season. The year 2015 was singled out as one of those in which significant values of mean annual and maximum discharges were recorded at the nearest hydrological stations Korvingrad and Mojsinje in the 50-year period (Langović, 2019). The same year, based on the classification of years by wateriness, was singled out as very rich in water, with an average annual discharge of 137 m 3 /s, compared to the average annual discharge for the entire period of 87 m 3 /s at the station Mojsinje (32% higher value).…”

“…Година 2015. је издвојена као једна од оних у којој су забележене значајније вредности средњегодишњих и максималних протицаја на најближим хидролошким станицама Корвинград и Мојсиње у 50-годишњем периоду (1968-2017. ) (Langović, 2019). Иста година је, на основу рангирања година према водности, издвојена као врло водна са вредношћу средњегодишњег протицаја од 137 m 3 /s, наспрам средњегодишње вредности за читав период која износи 87 m 3 /s на станици Мојсиње (за 32% већа вредност).…”