## 1 Introduction  
Sediment transport in surface waters is a complex dynamic process and has multiple implications, particularly in the areas of environmental protection, hydropower exploitation of rivers, flood risk management, and water resources management. Recently, suspended-sediment dynamics have been investigated intensively, as suspended sediment represents the majority of material that is in motion within a stream. The deposition of sediment in water bodies has significant impacts on the accumulation of silt in river channels, flood-prone areas, and surface waters such as lakes and coastal areas, as well as environmental impacts due to sediment-bound pollutants. Sediments found in rivers are a result of the weathering processes occurring on the upper layers of the Earth's crust, which interact with the forces of erosion that cause the movement of material and its transportation along river channels. Suspended-sediment concentration depends on the current flowrate, climate changes, glacial melting, and intense erosional processes. Human intervention in riverbeds, such as the construction of hydropower plants and other hydraulic structures, can have a significant impact on the transport dynamics and quantity of sediment in a watercourse. As a consequence of material transport, reservoirs and the riverbed become filled, which ultimately affects the natural hydrological cycle by reducing the discharge into aquifers [1; 2; 3; 4; 5; 6]. Previous studies investigating suspended sediment in Slovenian rivers [7; 8; 9; 10; 11; 12; 13] have indicated that the majority of the overall material is transported during periods of high water flow. However, not every high-water event increases the amount of suspended sediment, as the dynamics of sediment depend on the sum of hydrologic events in the river, the previous hydrologic condition, the intensity of precipitation in the hinterland, and many other factors. The source of suspended sediment can be predicted from the relationship between water discharge and the concentration of suspended sediments, which usually takes the form of a hysteresis loop during a high-water event. Depending on various factors during the event, e.g., runoff, erosion processes, and human activities, different forms of hysteresis loops are possible, e.g., a single-value (straight or curved) relationship, clockwise loop (positive), counterclockwise loop (negative), single-value plus a loop, and figure of eight [14; 15; 16; 17; 18]. The dynamics of suspended-sediment transport in streams has been intensively studied recently, as they are closely related to runoff formation and flooding. Erosion processes are particularly intense in agricultural catchments, where suspended-sediment transport dominates during flood events [19]. A comprehensive study of suspended-sediment transport using a log-time dataset to obtain more information about the factors that determine suspended-sediment transport in headwater watersheds was presented in [20]. In [21], the effect of urbanization on suspended-sediment flux in a selected watershed was investigated, and it became clear that sediment dynamics vary spatially and temporally. The high spatiotemporal variability in suspended-sediment transport allows the determination of sediment sources and a general understanding of erosion in the catchment, which is why the statistical analysis of hydrometeorological data is crucial, as presented in [6; 22]. In [23], different hysteresis relationships between suspended-sediment concentration and discharge due to catchment characteristics in a multiple catchment of the middle Yellow River were reported. A comprehensive understanding of the spatial and temporal dynamics of suspended-sediment concentrations requires properly calibrated and tested numerical models, as described in [24]. Measuring the amount and dynamics of suspended sediment in streams remains a complex problem, despite the existence of several established methods.