Sediment Transport Research Articles

Numerical Simulation of Wave-Induced Scour in Front of Vertical and Inclined Breakwaters

The erosion of the seabed in front of shoreline structures due to wave action is a critical concern. While previous models accurately depict fluid and sediment interactions, they each have limitations and require significant computational resources, especially when simulating complex processes. This study proposed and validated a numerical model for simulating wave-induced sediment transport by integrating three key components: (1) a main solver based on large eddy simulation that includes the porosity of permeable materials, (2) a volume of fluid module to track the air–water surface, and (3) a sediment transport module that includes both bedload and suspended load to compute sediment concentrations and seabed changes. The model was validated against previously published experimental data, demonstrating its accuracy in capturing both wave motion and seabed profile changes induced by sediment transport. Furthermore, the numerical model was applied to study the effects of varying breakwater slopes on sediment seabed profile changes. The results show that steeper breaker slopes led to more concentrated wave energy near the structure, resulting in deeper scouring and higher sediment displacement. These results indicate that the proposed model is a valuable tool for coastal engineering applications, particularly for designing breakwaters, to mitigate sediment erosion and improve sediment stability.

A CNN-Based Framework for Automatic Extraction of High-Resolution River Bankfull Width

River width is a crucial parameter that correlates and reflects the hydrological, geomorphological, and ecological characteristics of the channel. However, the width data with high spatial resolution is limited owing to the difficulties in extracting channel width under complex and variable riverine surroundings. To address this issue, we aimed to develop an automatic framework specifically for delineating river channels and measuring the bankfull widths at small spatial intervals along the channel. The DeepLabV3+ Convolutional Neural Network (CNN) model was employed to accurately delineate channel boundaries and a Voronoi Diagram approach was complemented as the river width algorithm (RWA) to calculate river bankfull widths. The CNN model was trained by images across four river types and performed well with all the evaluating metrics (mIoU, Accuracy, F1-score, and Recall) higher than 0.97, referring to the accuracy over 97% in prediction. The RWA outperformed other existing river width calculation methods by showing lower errors. The application of the framework in the Lillooet River, Canada, presented the capacity of this methodology to obtain detailed distributions of hydraulic and hydrological parameters, including flow resistance, flow energy, and sediment transport capacity, based on high-resolution channel widths. Our work highlights the significant potential of the newly developed framework in acquiring high-resolution channel width information and characterizing fluvial dynamics based on these widths along river channels, which contributes to facilitating cost-effective integrated river management.

Development of an acceleration method for sediment transport analysis with suspended load and bedload in an integrated river channel and coastal region

ABSTRACT To analyze sediment dynamics in estuaries during floods, a method capable of three-dimensional flows for high-resolution calculations is essential. However, such calculations are computationally intensive for midium to long term periods. We developed a high-speed calculation method for temporal variations in river bed topography and sediment discharge from river basins based on the average component acceleration (ACA) method by shortening the duration of floods. In the ACA method, the local components remained unchanged, and the temporal variation in the average components was amplified. This study developed the ACA method to calculate sediment transport, including bedload and suspended load, around an estuary. The ACA method enabled five times faster than the analysis of riverbed variations and the amount of sediment discharge compared to the conventiola non-accelerated analysis. It also accurately captured the widening of the estuarine sandbar opening during a flood demonstrating its utility for medium- to long-term riverbed-change analysisand its advantage over the other acceleration methods.

Distribution and bi-directional transport of surface sediments driven by monsoons on the northwest continental shelf of the South China Sea

Distribution and bi-directional transport of surface sediments driven by monsoons on the northwest continental shelf of the South China Sea

Detrital thermochronology histories preserved in Paleogene strata of Utah (USA) provide distant records of Paleozoic Alleghanian orogenesis and sediment dispersal

We present new zircon U-Pb and (U-Th)/He data from sandstone cobbles of the Paleocene−Eocene Wasatch Formation of northern Utah (western United States). Provenance data demonstrate that these zircons have been recycled through at least two sedimentary cycles, deposited first as sand grains in the Pennsylvanian−Permian Weber Sandstone and second as sandstone cobbles in the Wasatch Formation. The thermal history of these grains requires rapid Late Mississippian−Pennsylvanian cooling, preserving a new, distant record of early Alleghanian orogenesis that is also a distinct provenance signature. Zircon thermochronology provides a powerful archive of ancient exhumation patterns and continental-scale sediment transport and deposition. Our study demonstrates that such thermal histories are resilient throughout multiple episodes of recycling.

Inversion and analysis of transparency changes in the eastern coastal waters of China from 2003 to 2023 by an improved QAA-based method

Transparency (Zsd) can most intuitively reflect changes in marine ecosystems, therefore; the data of Zsd is crucial to protect marine ecosystems. However, there is still a relative lack of long-term sequence data on Zsd for coastal turbid waters. Satellite remote sensing inversion provides an efficient means of obtaining long-term, large-scale Zsd. The method proposed by Lee et al. is currently one of the most widely used methods, which is divided into clear water and turbid water models based on the 670 nm remote sensing reflectance (Rrs). In this study, we employed an improved model building upon the aforementioned method. The improved model simulates the continuous transition from clear to turbid water, which allows for automatic adjustment of model weights based on a logistic curve. Utilizing this improved model, this study inverts Zsd within 100 km of the eastern coast of China from 2003 to 2023 using MODIS Aqua Level 2 Rrs data. Zsd shows an increasing trend with the distance from the coast, with high Zsd in the northern Yellow Sea, the southern Shandong Peninsula, and the far shore of the East China Sea, and the low Zsd in the coast of Bohai Sea and northern Jiangsu. As for the long-term changes, the number of pixels with significantly increased Zsd and those with significantly decreased Zsd and no significant changes accounted for 20.84%, 1.14%, and 78.02%, respectively. The order of seasonal Zsd is summer > autumn > spring > winter, and the seasonal variability amplitude increases synchronously with the offshore distance of seawater on the whole. Interestingly, the correlation between Zsd and the annual runoff of rivers exhibits spatial differentiation among six typical estuaries: there are positive correlations in northern, whereas negative correlations in the south. Additionally, the Zsd in five of six estuaries have negative correlations with annual sediment transport. Overall, this study not only provides more accurate and continuous data of Zsd for nearshore turbid waters compared to those obtained by the original model, but also offers valuable insights on the spatiotemporal variation in the Zsd of large-scale seawater.

A NEW TURBIDITE FACIES TRACT SCHEME INCLUDING SUPERCRITICAL AND TRANSITIONAL SAND–MUD FLOWS: AN OUTCROP PERSPECTIVE FROM MEDITERRANEAN-TYPE FORELAND BASINS

The studies carried out on tectonically-confined turbidite systems in Mediterranean-type foreland basins have shown that these deposits can be dominated by supercritical flows and by their transformation into subcritical and/or transit ional (mud-sand) flows. In these confined turbidite systems, flow deceleration is favoured especially by morphologies transversal to paleocurrents, e.g., slope breaks or adverse slopes that can vary in scale from regional tectonic structures to depositional features such as thick mass-transport complexes and lobes. Based on data of more than fifty years of outcrop studies in foreland and wedge top basins, a new facies tract scheme is presented that includes the occurrence of supercritical flow deposits and hybrid event beds in turbidite successions. A review of the main turbidite facies schemes available in the literature is given, and detailed field examples of the Apennine and Alpine (Peira Cava) foreland basins are given that demonstrate the effect of basin morpholo gy on the type of facies tracts. The concept of flow efficiency is revisited as sediment transport depends not only on flow behaviour but also on basin size and basin-floor morphology (e.g., large foredeeps are characterised by facies that reflect high-efficiency, whereas small piggy back basins are characterised by facies related to low-efficiency transport).

Altered flow and sediment transport impacts on the ecosystems of Chinese major rivers: An urgent call for eco‐fluvial dynamics

Altered flow and sediment transport impacts on the ecosystems of Chinese major rivers: An urgent call for eco‐fluvial dynamics

Reducing direct physical disturbance also mitigates hidden drivers of decline in a threatened seagrass meadow

Physical disturbances typically cause ecological impacts within areas of direct contact (primary disturbances) but can also impact surrounding areas through other mechanisms (secondary disturbances). Secondary disturbances are often overlooked, especially in marine ecosystems where sufficiently detailed observation can be difficult to obtain. For example, boat moorings create circular clearings in seagrass meadows by physically scouring the seabed, but visible impacts extend beyond this into surrounding areas due to disturbances such as increased sediment transport, edge effects, and shading from boats. Previous studies on impacts of moorings have not distinguished between primary and secondary disturbances, and secondary disturbances are rarely accounted for in environmental management. We used spatial modelling to examine the primary and secondary disturbances associated with moorings in a meadow of the threatened seagrass Posidonia australis. We compared the disturbance from traditional ‘swing’ moorings with ‘environmentally friendly’ moorings (EFM) designed to reduce scour. Within the scour zone (0-5 m from moorings), we compared seagrass cover around swing moorings with cover around EFM. Further from moorings (5-25 m), we tested the degree of association between seagrass cover and secondary disturbances that may accumulate with mooring density and be influenced by mooring design. We found that mooring design affected the degree of direct disturbance, with cover of P. australis in the scour zone of standard moorings ~49% lower than that of EFMs (p < 0.01). Mooring density had cumulative negative effects on P. australis cover in the surrounding meadow, but the influence of mooring density was reduced when most moorings were EFMs. This suggests that secondary effects contingent on direct physical disturbance (e.g. sediment transport, fragmentation, edge effects) may be stronger than the general influence of moored boats (shading). We use the findings to simulate two broad policy scenarios for mooring designs in P. australis meadows: installing only EFM, or only traditional moorings. The simulations suggest that using only EFM would lead to a 14.2% increase (~164 m2), whereas installing only traditional moorings would lead to a 16% (~187 m2) loss of P. australis cover in this already highly disturbed meadow. Synthesis and applications: We demonstrate a nondestructive approach to assessing primary and secondary disturbances driving the distribution of a threatened seagrass and simulate a range of potential management scenarios that could assist in conserving the species.

A Holistic Approach for Coastal–Watershed Management on Tourist Islands: A Case Study from Petra–Molyvos Coast, Lesvos Island (Greece)

Shoreline configurations are a complex outcome of the dynamic interplay between natural forces and human actions. This interaction shapes unique coastal morphologies and affects sediment transport and erosion patterns along the coastline. Meanwhile, ephemeral river systems play a vital role in shaping coastlines and maintaining ecosystem sustainability, especially in island settings. In this context, the present study seeks to develop a holistic approach that views coast and watershed systems as a continuum, aiming to investigate their relationships in an island environment, while accounting for human interventions in the river regime. For this task, the empirical USLE method was employed to quantify sediment production and transport from the catchment area to the coast, while hydraulic simulations using HEC-RAS were conducted to assess sediment retention within flood-affected areas. Moreover, coastal vulnerability to erosion was evaluated by applying the InVEST CVI model in order to identify areas at risk from environmental threats. The coastal zone of Petra–Molyvos, Lesvos, Greece, was selected as the study area due to ongoing erosion issues, with particular emphasis on its interaction with the Petra stream as a result of significant human intervention at its mouth. According to the study’s findings, the examined coastal zone is highly vulnerable to combined erosion from wind and waves, while the river’s mouth receives only a small amount of sediment from water fluxes. Evidently, this leads to an increase in beach retreat phenomena, while highlighting the necessity for integrated coastal–watershed management.

Use of Geomatic Techniques for Mapping Suspended Solids in Aquatic Ecosystems: The Case Study of Guayas River, Ecuador

Satellite images cover large remote areas and are useful for detecting and monitoring water bodies. In Ecuador, since 1950, the lower Guayas River basin has undergone significant natural and anthropogenic changes that have impacted its dynamics and sustainability. This study aims to analyze through in situ data and geomatic techniques the change that the river has undergone in a decade by mapping the Suspended Sediment Concentration (SSC). Increasing levels of pollution in the river have raised concerns, prompting various approaches to measure and mitigate sedimentation to maintain the sustainable quality of the watershed. The spatiotemporal variations of SSC in the Guayas River revealed a remarkable variability, influenced by the operation of reservoirs, changes in land use, erosion, and sedimentation causing SSC in 2013 to range from 64.82 to 707.06 mg/l in the satellite image of 9/16/2013 and from 87.58 to 933.36 mg/l in the image of 7/26/2023. Understanding this distribution is crucial for the environmental protection and sustainability of aquatic ecosystems. This study used Landsat 8 data, an atmospheric pre-correction, and a remote sensing model. The results indicate a creasing trend of SSC in the stretches of the Guayas River between 2013 and 2023, which allows the understanding of the spatiotemporal dynamics of suspended sediment transport.

Validation of Soil Detachment Rate Equations on Spring Thaw Period Slopes: Insights From Sediment Concentration and Transport Capacity

AbstractSoil detachment plays a central role in the formulation of soil erosion models, particularly for the simulation and prediction of erosion in cold climates during the thaw period. This research attempts to elucidate the mechanisms of soil detachment on spring thaw period slopes through comprehensive flume experiments, coupled with the application of rare earth element (REE) tracer, investigating the relationships between soil detachment rates, sediment concentration and sediment transport capacity. Observations indicate a nuanced response of soil detachment rate and sediment concentration to scour duration, characterized by an initial increase, subsequent decrease and eventual equilibrium. As thaw depth increases, the primary source of eroded sediment gradually shifts from the upper slope to the mid‐slope. Soil detachment rate was affected by sediment concentration, flow discharge, slope gradient, thawing depth, and slope positions. Furthermore, our analysis reveals a power function relationship (R2 = 0.846) between soil detachment rate, effective shear stress, and sediment transport rate and capacity. These results provide valuable insights into the modeling and prediction of soil erosion processes on brown soil slopes subjected to spring thaw period cycles.

MORPHODYNAMIC CHARACTERISTICS OF A SANDY BED MEANDERING CHANNEL AT DIFFERENT DISCHARGES

Transportation of sediment is a critical issue in riverine environments, particularly in meandering channels where flow dynamics are complex. However, information regarding erosion and deposition processes in meandering channels is still limited. Therefore, an experimental investigation on the influence of discharge variation on the morphodynamics of a meandering channel has been carried out. The experimental investigation was conducted at the Hydraulic and Hydrology Laboratory, UTM Johor Bahru. The study investigates the flow profiles and the morphological changes of inbank flow conditions represented by shallow and deep flow depths. The findings revealed that Manning’s n in a deep flow depth was 60.12% higher than a shallow flow depth. Moreover, velocity at the channel bend was increased by 8.3% to 14.6% compared to the crossover along the channel. This indicates that the geometrical planform plays a crucial part on the variability of velocity in the channel. Therefore, the outcomes of this study could provide more effective river management strategies to resolve erosion and deposition issues in river engineering studies.

Experimental investigation of turbulent energy spectra affected by submerged vegetation in shallow open channel flows

In the presence of vegetation in open channel flows, various physical processes, such as sediment transport, may be dominated by large-scale eddies, of which mechanisms are not well understood at present. In this study, we aimed to explore vegetation-affected turbulence from the perspective of energy spectral analysis. First, we conducted a series of laboratory experiments of open channel flows with submerged vegetation by varying the flow rate, water depth, and vegetation density. With flow velocities measured using the particle image velocimetry (PIV) technique, energy spectral analyses were then performed over several representative locations in the flow field. The results show that the Kelvin–Helmholtz (KH) vortices dominate the flow in the surface layer, while the shedding wake controls the flow in the vegetation layer, particularly downstream of individual vegetation stems. The normalized frequency of the KH vortices increases for flows with dense vegetation, of which the peak value, when normalized as the Strouhal number, has an average of 0.21. Furthermore, by applying Taylor's frozen turbulent hypothesis, it is shown that both the scale of the KH vortices and the penetration depth reduce when the vegetation becomes dense. Within the vegetation layer, the minimum of the peak streamwise wavelength is observed to be related to the shedding wake, while its maximum scales with the size of the penetrating KH vortices.

A New Method for Analyzing Storm Event Discharge‐Concentration Hysteresis: The Upper Yangtze River as an Example

AbstractThe analysis of hydrological and sediment dynamics during flood events offers a new perspective on material transport within basins and the management of rivers. The literature has highlighted the hysteretic nature of material transport at the event scale, which arises from temporal differences in the transport of materials (flow and sediment). Current hysteresis research methods fall short in effectively assessing the complex events. This study leverages suspended‐sediment and discharge data from the upper Yangtze River to show proof‐of‐concept for hysteresis studies using Dynamic Time Warping (DTW) algorithm, a time series analysis tool. To evaluate the efficacy of the method, extensive assessments were undertaken using a combination of synthetic data and basin data with over 700 flood events. The proposed index effectively captures and quantifies hysteresis relationships associated with flood events, making it a versatile tool for hysteresis studies. We also similarly tested the robustness of the method and the application to complex events, and the results were satisfactory. Furthermore, we explored the hysteretic features of flood events in the studied basin. The results revealed that a proportion ranging from 50% to 60% flood events exhibit sediment peak leading pattern, indicating that in the upper Yangtze River, sediment peaks tend to occur in a leading pattern. The operation of reservoirs profoundly impacts the dynamics of sediment transport, resulting in an increased proportion (from 27% to 54%) of sediment peaks lagging behind discharge peaks. These study findings can be used to improve hysteresis study methods and contribute to the understanding of hydrological and sediment transport characteristics.

Impacts of Post‐Fire Debris Flows on Fluvial Morphology and Sediment Transport in a California Central Coast Stream

AbstractPost‐fire debris flows alter impacted fluvial systems, but few studies quantify the magnitude and timing of reach‐scale channel response to these events. In August 2020, the Big Creek watershed along California's central coast burned in the Dolan Fire; in January 2021, an atmospheric river event triggered post‐fire debris flows in steep tributaries to the Big Creek. Here, we characterize the evolution of fluvial morphology and grain size in Big Creek, a cascade and step‐pool channel downstream of tributaries in which post‐fire debris flows initiated, using pre‐ and post‐fire structure from motion (SfM) and airborne lidar surveys. We also make comparisons to Devil's Creek, an adjacent basin which burned but did not experience post‐fire debris flows. We observe grain size fining following debris flows in Big Creek, but the coarsest 40% of the grain size distribution remained essentially unchanged despite reorganization of channel structure. Changes in grain size and elevated post‐fire peak flows account for approximately equal portions of a substantial increase in modeled bedload transport capacity one year post‐fire. In Big Creek, geomorphic recovery is well underway just two years post‐fire. A valley‐spanning log jam, which formed during debris flows, acts as a sediment trap upstream of our Big Creek study reach, and is partially responsible for accelerating recovery processes. In contrast, Devil's Creek exhibited little change in morphology or grain size despite elevated post‐fire peak flows. This period of geomorphic dynamism following the Dolan Fire has complex ecological impacts, notably for the threatened anadromous salmonid spawning habitat in Big Creek.

Reduced magnitude of Early Pleistocene intensification of Northern Hemisphere Glaciation

Increased magnitude and expanding geographic distribution of ice-berg rafted debris in deep ocean sediment cores and increasing amplitude of variability in the benthic oxygen isotope (δ18O) proxy-global ice volume from ∼2.7 Ma marks the intensification of the Northern Hemisphere glaciation (iNHG). However, the location, extent and volume of Northern Hemisphere Ice Sheets (NHISs) is poorly constrained by proximal geologic evidence, and global sea-level records cannot determine individual polar ice sheet contributions alone.Quantitative relationships between sediment transport, water depth and grain size on a wave-graded continental shelf were previously applied to Pliocene shallow-marine sedimentary deposits in Whanganui Basin, New Zealand to provide an independent relative sea level record (PlioSeaNZ; 3.3–2.5 Ma). Here, we extend the duration of the sea-level record from 3.3 to 1.7 Ma (X-PlioSeaNZ) using a well-documented, shallow-marine sedimentary succession, that outcrops in the Rangitikei River Valley of the Whanganui Basin.The resulting glacial-interglacial, relative sea-level fluctuations are up to 45 ± 12.5 m paced by 41 kyr-obliquity frequency during the Early Pleistocene, but also contain modulation of 100 kyr-eccentricity cycle. These maximum sea-level amplitudes are more comparable to the mean of those previously reconstructed from calibrated benthic δ18O (e.g. Miller et al., 2020), and are significantly lower than estimates provided by albeit limited geological evidence proximal to the NHIS (Batchelor et al., 2019). Here we suggest that while NHISs acquired continental extent by 2.6 Ma, their collective volume may be overestimated in benthic δ18O calibrations and area-volume reconstructions, by as much as 50%.We propose that a reduced aspect ratio of ice sheets during iNHG was driven by 41-kyr changes in integrated summer insolation and enhanced by a subglacial regolith feedback reducing resistance to basal sliding. Regardless, the lower ice volume through the iNHG implies a lower ice sheet sensitivity (ice equivalent sea-level per degree Celsius change in temperature) under higher atmospheric CO2 of 4–6 m/°C compared to ∼20 m/°C for the period since the Last Glacial Maximum. This ice sheet sensitivity still has significant implications for society and sea-level will continue to rise under current emissions.

Sedimentary dynamic processes affected by tropical cyclones and anthropogenic forcing in a small-scale estuary: The Sheyang River Estuary, China

Amid the robust landward migration of tropical cyclones (TCs) in the context of global warming, the sedimentary dynamic processes in coastal areas are increasingly affected by TCs. Concurrently, coastal environments face tremendous stress from anthropogenic interventions, such as land reclamation and jetty construction. However, most research puts more emphasis on TC impacts on large-scale estuaries or marginal seas, leaving the sediment dynamics in small estuaries, particularly under the influence of TCs and man-made structures, largely unexplored due to the limited field data. To address this issue, this study took the Sheyang River Estuary (SRE) as an example and explored the sediment dynamic responses to TCs and the jetty construction during Typhoon Lekima in August 2019, utilizing the Finite Volume Coastal Ocean Model (FVCOM). The results showed that the rotating wind field of Lekima induced rapid variations in wave height, residual water level, and currents at different typhoon stages and strengthened the sediment resuspension and alongshore transport. Furthermore, by comparing the effects of Lekima with Typhoon Chan-hom in July 2015, we found that TCs with different tracks produced markedly different dynamic processes, yet all facilitated sediment exchange between the northern and southern areas within the SRE. The study also highlighted the impact of jetty construction on sediment transport during typhoons, noting that jetties can disrupt the typhoon-induced alongshore sediment flux and create eddies on either side by altering sediment advection. In the navigational channel area, the construction of jetties can strengthen the along-channel estuarine circulation during typhoon events, potentially leading to severe channel siltation by trapping riverine sediments and inducing net landward sediment transport. While site-specific, this study provides valuable insights into the combined effects of extreme events and human interventions on sedimentary environments in small estuaries.

Advancing mechanistic understanding of cohesive sediment transport: Integrating flume experiments, field measurements, and modelling approaches in a gravel-bed river

Gravel-bed rivers draining mountainous forested headwater regions are critically important for drinking water supply and ecological integrity. These rivers, however, have been increasingly impacted by intensifying anthropogenic and natural (especially climate change exacerbated) landscape disturbances that commonly increase hillslope/channel connectivity and the delivery of cohesive sediment (<63 μm) and associated pollutants. Despite the known deleterious threats of excess cohesive sediments, there is still limited understanding of their transport and intra-gravel storage due to the complexities of such processes. Accordingly, the objectives of this study were to: i) calibrate and validate a semi-empirical cohesive sediment transport model (RIVFLOC) using the observations from flume experiments; ii) estimate the intra-gravel storage capacity for cohesive sediment with the calibrated model based on the field dataset (collected in two field campaigns between 2019 and 2021), and; iii) investigate mechanisms of cohesive sediment transport dynamics in this gravel-bed river, identifying knowledge gaps and areas for future research. Our results showed that despite the increased floc settling velocity, deposition was hindered by turbulent flow fields. The model predicted that ~60 % of upstream cohesive sediment would ingress within the 10 km study reach due to the flow interaction with the gravel-bed. Despite the agreement between flume and field observations on ingress rates and preferential ingress of coarser (~100 μm) flocs, notable differences were observed between modelled and field datasets, highlighting unknowns regarding cohesive sediment exfiltration without framework mobilization. This study uniquely integrates field measurements, flume experiments, and modelling strategies to evaluate the transport and fate of cohesive sediment in a gravel-bed river. Accordingly, our findings advance current knowledge on the mechanistic understanding of cohesive sediment transport and highlight future research directions.

Deciphering the grain size fining and provenance variation of lower Yellow River fluvial sediments in light of Holocene climatic changes and anthropogenic influences

The dynamics of fluvial processes in the lower Yellow River during the warm Early and Middle Holocene can serve as an analogue for future global warming, thus providing a scientific basis for addressing contemporary river issues. However, the Early and Middle Holocene riverbed sediments in the lower Yellow River have rarely been investigated. Here, we conducted detrital zircon UPb dating and grain-size analysis of four riverbed samples with different ages collected via four boreholes across the North China Plain. Our results revealed that during the Early Holocene, coarse-grained sediments derived from upstream mountains were widely present as a result of gradually increasing precipitation. During the Middle Holocene, riverbed sediments gradually became finer due to the increased input of fine-grained sediments from the Chinese Loess Plateau following the northward shift of the rain belt. During the Late Holocene, riverbed sands continued the fining trend because of reduced stream flow, which limited the transport of coarse-grained sediments into the lower reaches. Continuous enhanced anthropogenic influences resulted in more fine-grained sediments in the riverbed. We conclude that millennial-scale precipitation variation controlled the flow discharge and sediment composition in the lower Yellow River during the Holocene. Our findings suggest that increasing flow discharge through water regulation can effectively address current challenges and help adapt to future global warming.