Author(s): Ellie Buehrer; Fatemeh Shacheri; Muhammad Alif; Jonathan Czuba

Linked Author(s): Jonathan Czuba

Keywords: Fine sediment; Freshwater mussel; Sediment transport; Sediment traps; Shear velocity fine sediment; Freshwater mussel; Sediment transport; Sediment traps; Shear velocity fine sediment; Freshwater mussel; Sediment transport; Sediment traps; Shear velocity

Abstract: Excess fine sediment , which we generally refer to here as particles < 2 mm diameter, adversely affects benthic organisms by limiting habitat availability and exchange of oxygen and nutrients (Von Bertrab et. al., 2023). Fine sediments also play a crucial role in shaping the geomorphology of rivers by influencing channel dynamics, sediment transport processes, and riverbed stability (Owens et al., 2005; Dubius & De Cesare, 2023). Fine sediment can accumulate on and around the riverbed substrate, and excessive accumulation may lead to riverbed clogging – the filling of substrate pore spaces – which can negatively impact aquatic species that rely on these spaces for habitat and reproduction (Wharton et al., 2007; Dubius & De Cesare, 2023). Fine particles, such as sand (62.5 µm – 2 mm) and silt (4 µm – 62.5 µm; Garcia, 2008), are often suspended in the channel but can settle into the bed during low flows (Diplas, 1994; Skalak & Pizzuto, 2010; Dubuis & Cesare 2023; Wharton et al., 2017). Sediment traps can be used to estimate material that will settle in a particular area but not do not measure net sedimentation rates (Hedrick et al., 2013; Maltauro, et al., 2023). The theories used for fine sediment deposition and transport have also been used to describe the behavior of biota, including drift and dispersal of aquatic invertebrates, drift of fish eggs, and settling of juvenile freshwater mussels (Anderson et al., 2013; Garcia et al., 2013; Sumaiya et al., 2024). Juvenile freshwater mussel settling, specifically, can be described in the same way as fine sediment settling from suspension in the water column. Like suspended sediment, the shear velocity in the river must be less than the mussel settlin g velocity for it to be able to settle to the bed (Sumaiya et al., 2024). The purpose of this study is to better understand the spatial patterns of fine sediment deposition , and therefore also juvenile freshwater mussel settling in a gravel-bedded river. This work is guided by the hypothesis that certain areas along a riverbed experience lower shear stresses than the surrounding area, possibly due to large boulders, wood, or simply the bathymetry of the channel, and will allow fine particles, particularly silt, to settle out of suspension. This was evaluated through a combination of fine sediment deposition measurements in the field, 2D hydrodynamic modeling, and statistical analysis of the results.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.183

Year: 2026