Zapadna Morava River basin covers a surface of 15850 km2, which is approximately 18% of the territory of the Republic of Serbia. In its basin, 38 active surface stations are registered. The goal of this paper is the trend analysis of the mean annual river discharges in the Zapadna Morava River basin and their noticing in a longer series of time, as well as determining their intensity. Fifty years period of time (1965 - 2014) is taken for a time series. Because there is no empirical data for mean annual discharge values for all stations for the given period, the number of the hydrological stations, which are processed in this paper, is reduced to 21. Mann-Kendall test has been used for noticing the trend, Sen test has been used for estimating the curves inclinations of the linear trend, while Pettitt?s test has been used for determining the turning point of change. Also, classification of the years by water richness has been performed in this paper in order to determine wet and dry periods. For the needs of identification of medium watery, wet and dry years, the combined method has been used on the data examples from representative stations in the basin. Based on the processed data and the obtained results, it has been established that the most rivers in the basin of the Zapadna Morava River have a slightly decreasing trend of the flow values, whereby the change of the trend is not significant. On the most rivers, the change period has begun in the early eighties of the past century. On a large number of profiles, the watery period was appearing in the beginning of eighties, while the dry season is characteristic for the period from 1990 to 1994.

In many Eastern European countries, the standard of living increased as a result of the process of industrialization in the second half of the 20th Century. Consequently, the population in rural areas with small-scale farming decreased due to the availability of employment elsewhere. This directly impacted soil erosion (and thereby sustainability of the land), but the degree and direction are not well known. This study investigates two municipalities within Serbia, their change in population and its impact on land use changes and soil erosion. The standard of living increased after the industrialization process in the 1960s within these municipalities. The erosion potential model is used to calculate gross annual erosion. The changes related to population and arable land in rural settlements are analyzed according to proportional spatial changes. The results show an overall decrease of erosion intensity in the study area. In addition, two basic findings are derived: first, the highest level of human impact on soil is in rural settlements at the lowest elevation zones, where erosion intensity shows the least amount of decrease; and, second, the most intensive depopulation process, recorded in higher elevation zones, indicates a rapid decrease of erosion intensity.

Torrential floods are the most frequent natural hazard events in Bosnia and Herzegovina. The increase of intensive rains in Bosnia and Herzegovina over last years, as a consequence of the climate changes, has triggered many torrential floods, which have generated a lot of damages and losses of human lives. This study was focused on development of torrential susceptibility model using GMM Method and GIS in the Vrbas river basin as an attempt to create a new methodological approach which can be used on other river basins in Bosnia and Herzegovina. First, a total of 174 torrential basins were identified in the Vrbas river basin, as a base for creating an inventory map, which was a base map for the assessment of torrential floods susceptibility. The GIS Matrix Method and six influencing factors were used for generation of Torrential Flood Susceptibility Model. Based on the obtained values of Torrential Flood Susceptibility Model for the Vrbas river basin, 45.52% of the study area is within strong and very strong susceptibility category. The Torrential Flood Susceptibility Model was validated using a "degree of fit" method. Validation indicators of the TFSM show that the 80.04% are in the category of strong and very strong susceptibility, while only 4.37% are in the category of very low and low susceptibility. This fact suggests that used methodology based on GMM method and used influencing factors enable delimitation of the area with high and very high susceptibility to torrential floods into the Vrbas basin. Therefore, used methodological approach represents a good base for future research, and it has potential for the practical use and should be tested in other river basins in Bosnia and Herzegovina.

Abstract:Considering recent weather events in Serbia (especially the floods in 2014), a need has arisen for research that would help in identifying extreme weather phenomena. Therefore, the aim of this paper is to determine the thresholds above which intense precipitation can be considered as extreme precipitation events in Serbia. In this study, we determined the frequency of precipitation occurring at an intensity above the threshold of an extreme phenomenon , as well as the frequency of precipitation occurring at or above the absolute daily maximum in the reference period . The study sample included daily rainfall observations from 28 stations from the national meteorological network in Serbia. Applying a decile method, all the stations recording precipitation above the threshold of dangerous phenomena on the same day are classified into the corresponding decile. The threshold value was determined as the average value of the extreme annual precipitation in the analyzed period. The cases that are due to the high prevalence listed in the last decile are considered extreme. The results showed that the critical number of observation points above which an event is considered extreme precipitation event is 6.21, and a warning of the danger could be ensured only in the case of neighboring stations in the network. The threshold of extreme precipitation events for the individual stations ranges up to 130 mm. The obtained results might be used to mitigate the effects of extreme precipitation events in Serbia in the future.

This study expounds the dynamic relationships among agricultural land-use change, rural population migration, and sediment transport. The variability of suspended sediment load was detected by Mann–Kendall and Pettitt tests. From 1961 to 2007, the annual trend in suspended sediment concentration and sediment load demonstrated significant reduction (α = 0.001), with decreasing rates of 0.0144 g/L/y and 84.7 t/y, respectively. An abrupt change-point was detected in 1984 for the sediment load (p = 0.0001). The double-mass curve method and regression analysis of sediment load versus precipitation were used to quantify the effects of climate change and human activities on sediment load variations. The changes in sediment load were predominantly impacted by human activities (89%), while precipitation explained 11% of the reduction in suspended sediment. An important land-use change recorded in the Južna Morava river basin comprised the abandonment of agricultural lands due to depopulation processes, as well as economic and social changes, which was followed by significant impacts on soil erosion and sediment transport. Land abandonment was most pronounced in marginal mountain or semi-mountainous areas, where agriculture was until recent decades traditional or semi-traditional. The results of the correlation matrix were significant at the p < 0.05 level, demonstrating that the decrease of rural population, agricultural land, and arable land were directly related to the decline of suspended sediment. High correlation coefficients were found between anthropogenic indicators and sediment parameters, ranging from 0.94 to 0.97.