What factors affect the suspended sediment concentrations in rivers? A study of the upper Warta River (Central Poland)

Abstract

The suspended sediment concentration (SSC) of the Warta River was analysed using data collected at the Sieradz gauging station (Central Poland) during the period of 1961-1980. The aim of the study was to characterize the trend in the suspended sediment transported over this multi-annual period and search for possible correlations between the suspended sediment values and the discharge and thermal seasonality factors. This study also investigated whether the SSC is affected by anthropogenic factors. The SSC in the river water increased over the analysed 20-year period. It was caused mainly by the training works in the Warta valley upstream of Sieradz and the opening of the Bełchatów lignite mine. No direct relationship between the SSC and fluctuations in the discharge was noted. A connection existed between the SSC and ice phenomena on the river. The river ice breakup was often coincident with increases in SSC; however, the SSC increased rapidly during the freezing of the river. There was also a positive correlation between the SSC and the temperature of the water during the summer half-year, which resulted from the growth of phytoplankton. This process was supported by the general warming trend observed in the river water and by an increase in the quantity of nutrients noted since the early 1970s. It is worth emphasizing that the relationships established between the SSC and the studied factors are not always unequivocal and repetitive. It follows that, as a rule, the SSC is influenced by more factors than are actually considered in this study.

A two-decade record of variations in suspended sediment in the Warta River, a lowland river in western Poland

“…Only the presence of ice cover can in duce a rapid in crease of SSC. At Sieradz in 1969, the pres ence of ice cover was found to have a sig nif i cant in flu ence on SSC and max i mum SSC in the pe riod ana lysed, prob a bly by in ten si fied riverbed ero sion as a re sult of tun nelled flow (see Skolasiñska and Nowak, 2018). How ever, the sus pended load quickly re turned to the pre vi ous low level (Figs.…”

“…Stud ies of sus pended sed i ment trans port in rivers are compli cated be cause (Vercruysse et al, 2017;Skolasiñska and Nowak, 2018;Peng et al, 2020):…”

“…An at tempt was also made to as sess the in ten sity of de nu da tion pro cesses across Po land us ing SSC mea sure ments (Brañski and Banasik, 1996). A fur ther study by Skolasiñska and Nowak (2018) of SSC lev els in the Warta River at the up stream gauge sta tion in Sieradz dur ing 1961-1980 found max i mum SSC levels to be as so ci ated with anthropogenic fac tors, such as the dis posal of the wastewater from a lig nite open-pit mine and numer ous river train ing works. More im por tantly, SSC was not found to be di rectly pro por tional to dis charge lev els.…”

“…po ten tial long-term trends at all sta tions; ma jor fac tors con trol ling the max i mum SSC val ues; how the sus pended sed i ment load changes over the course of the river. Since no cor re la tion be tween SSC and dis charge was identi fied in pre vi ous stud ies (Skolasiñska and Nowak, 2018), this is sue is ad dressed in the pres ent study.…”

Controlled Reservoir Drawdown—Challenges for Sediment Management and Integrative Monitoring: An Austrian Case Study—Part A: Reach Scale

“…Thus, the impact assessment frequently addresses the suspended sediment concentration (SSC), which defines the total amount of both the mineral and organic material carried in suspension by an open channel flow [37]. However, independent of the reservoir impacts, the transport of suspended sediments in a river environment is highly non-linear in time and space, e.g., [38] and is influenced by many factors, including the geological framework, climatic conditions, and the topography of the drainage basin [39,40]. In addition to the well-known single-cause relationships for various aspects in sediment management of reservoirs, only minor studies, e.g., [41] deal with a detailed integrative assessment of sediment management measures.…”