CSU WES Seminar - 04.01.2026 Dr. Kyle Strom (Virginia Tech)

Title: Mud transport in rivers: lab and field observations and implications for the modeling of fine sediments Fine muddy sediments are found in riverine and oceanic flows and deposits all along the sediment source-to-sink pathway. From mountain streams to deep-ocean boundary currents, mud composed of inorganic and organic material is being produced, eroded, transported, and deposited along with other sediments such as gravel and sand. Yet, predicting mud movement in any environment is poorly constrained. Part of the difficulty in accurately modeling mud movement is an outcome of our limited ability to measure and model how mud particles change when suspended in water or move along or are deposited within the bed. Small mud particles tend to clump together, and form aggregates known as flocs (see figure below, far right), which grow or shrink in size and density because of the level of fluid turbulence and the biogeochemical properties of the suspension. As flocs grow or shrink in size and density, the speed at which they settle changes. As a result, it is imperative to be able to measure and model mud flocs as flow conditions, water chemistry, and biology change in river, estuarine, and marine systems for accurate prediction of mud transport and sediment-induced bathymetric change. In this talk, I present elements of the work our group and collaborators have conducted in the field and lab over the past few years to improve our ability to measure flocculated mud suspensions, predict how mud flocs transform spatially and temporally under varying turbulence, ionic strengths, and biological conditions, and to understand how they interact with the bed.