Fine sediment transport is currently attracting increasing attentions owing to its importance in the dynamics of sediment-contaminant interaction in the fluvial environment downstream of dams, which calls for more detailed and accurate flume experiments. However, because of inaccurate loading and undesired recirculation of fine sediment in the usual short laboratory flumes, such experiments are often unrepeatable and unreliable. In this technical note, we propose a new sediment feeder, to load dry sediment sample at the inlet, and a pressurized sediment filter, to screen the sediment out at the outlet, to implement a clear-water supply system for the flumes. It can improve fine sediment experiments not only by accurate loading but also through preventing undesired sediment recirculation, which can interfere and even modify the designated upstream input conditions. These devices have been constructed and tested, shown to be practical, simple and effective. Using them together can also provide a way to reclaim all the samples of experimental sediment that are of crucial importance for repeat and multiple tests for different contamination with a given sediment without losing the prescribed composition and other properties. This implementation is especially suitable for simulating fine particle affinity contaminant transport in fluvial turbulent flows in low sediment concentrations.

Accurately quantifying vertical sediment transport rates in large seaward rivers is vital for estimating basin-scale water and sediment fluxes and assessing riverbed evolution. Traditional multi-point velocity and suspended sediment concentration (SSC) measurements are costly and slow, hindering long-term online monitoring. Bidirectional flows in tidal reaches further exacerbate this challenge. We propose a physics-constrained support vector machine (SVM) inversion method to estimate vertical sediment transport rates from single-point measurements. Constrained by modified logarithmic velocity and Rouse suspended sediment concentration profiles, it quantitatively relates single-point hydraulic variables to key parameters governing vertical distributions. Lower Yangtze River tidal reach field data validate the hybrid model’s successful reconstruction of vertical distributions. It accurately captures transient sediment responses across maximum flood and ebb. Inverted transport rates match measurements closely (RMSE = 0.085, NSE = 0.969, PBIAS = 2.50%) and exhibit strong cross-site generalization. Sensitivity analysis identifies 0.4 times the water depth above the riverbed as the optimal single-point sensor position. Although currently validated only in the lower Yangtze River, this low-cost, reliable method supports local basin management, flood control, and disaster mitigation by enabling continuous sediment flux monitoring. However, applying it to other river or estuarine systems may require recalibration or retraining to adapt to different local conditions.

Suspended sediment concentration and transport processes are important controls on channel morphodynamics, hydraulic-engineering safety, and aquatic ecological and biogeochemical processes. Continuous monitoring supports flood regulation, reservoir operation, and navigation maintenance, and is also directly related to particulate carbon, nutrient, and contaminant transport, light attenuation, primary productivity, habitat quality, and the evolution of estuarine turbidity maxima. This framing expands SSC monitoring from a hydraulic measurement variable to a biogeoscience observation variable. This technical review uses a thematic literature search and synthesis to examine online and in situ monitoring methods for suspended sediment, including optical, acoustic, differential-pressure, vibration, electrical, nuclear, and sampling-based approaches. It compares their measurement mechanisms, applicable ranges, calibration needs, field deployment, and uncertainty sources. The review shows that sensor outputs cannot be directly equated with suspended sediment concentration. Site-specific conversion relations must be established by considering particle size, mineral composition, concentration range, hydrodynamic conditions, and paired sampling. Relations between turbidity, acoustic backscatter intensity, remote-sensing reflectance, and SSC are strongly site dependent, and nominal instrument accuracy cannot be directly converted into SSC accuracy. Future research should build a reproducible technical framework that integrates acoustic-optical retrieval, representative cross-sectional deployment, joint laboratory and field calibration, automated quality control, long-term drift correction, and uncertainty reporting.