Author(s): Ludovico Agostini; Peter Molnar

Linked Author(s):

Keywords: Suspended sediment transport; Turbidity; Timeseries analysis; Ecohydraulics; High resolution

Abstract: Catchment sediment supply and local channel sediment transport determine the river reach sediment regime. The fine sediment contribution controls ecology, habitat niches and water flow quality of the river reach. Due to its importance in ecohydraulics and its relation to hydropower generation, multiple networks of turbidity station s are being deployed by most of the government organizations across the Alps. Disentangling suspended sediment sources and sinks remains challenging, as conventional techniques for analyzing high-resolution measurements typically require substantial a priori knowledge of these components and their functional connectivity throughout the catchment. To solve this, we propose RETRACE (Routing & Event Time- differencing for Response Analysis of mass Changing Events), a timeseries analysis framework that leverages the coupled measurements of streamflow Q and suspended sediment concentrations SSC from two stations. The framework extracts water and sediment events, analyses the sediment exchanges during each of them, and with a physically based method, classifies them into those controlled by catchment supply or by channel erosion and deposition dynamics. RETRACE results also show a clear seasonal shift in controls: channel dynamics prevail in spring and autumn, whereas catchment dynamics drive the suspended -sediment exchanges in summer. This predominance of channel control underscores the important role of the river network in modulating sediment fluxes by intermediate channel storage, with consequences for river habitat and aquatic ecology.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.313

Year: 2026