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The erosion‐deposition propagation of granular avalanches is prevalent and may increase their destructiveness. However, this process has rarely been reported for debris flows on gentle slopes, and the contribution of momentum hidden under the surge front to debris‐flow destructiveness is ambiguous. Therefore, the momentum carried by the apparent surge front is often used to indicate debris‐flow destructiveness. In this study, the erosion‐deposition propagation is confirmed by surge‐depth hydrographs measured at the Jiangjia Ravine (Yunnan Province, China). Based on simple hydraulic jump equations, the eroded deposition depth of surge flow is quantified, and the erosion pattern can be divided into two patterns (shallow and deep erosion). For surge flows with erosion‐deposition propagation, significant downward erosion potential is confirmed, and debris‐flow surge erosion is considered the deep erosion. The total momentum carried by surge flow is further quantified by two Froude numbers (surge‐front and rearward Froude numbers) and verified through the field observation of surge flows. The total momentum of surge flow not only originates from the apparent surge front, but also includes the momentum within the eroded deposition layer. This study provides a theoretical approach for quantifying the upper limit of erosion depth and revealing the destructiveness of debris‐flow surges. A perspective on the importance of substrate deposition for debris‐flow erosion on gentle slopes is emphasized, as this approach can improve the reliability of debris‐flow risk assessment. Plain Language Summary For flow‐type mass movements consisting of multiple surges, a subsequent surge would entrain the deposition of previous surges. The subsequent surge continues to move forward until it deposits again. This deposition is in turn carried away by the subsequent surges. This process is termed erosion‐deposition propagation. The erosion‐deposition propagation widely occurs in snow avalanches and enhances destructiveness by amplifying the scale and mobility of avalanches. For debris flows on gentle slopes, erosion‐deposition propagation has not been reported, and the effect of this process on debris‐flow destructiveness is unclear. In this study, the erosion‐deposition propagation of debris flows is confirmed by the field observation of surge flows at the Jiangjia Ravine (Yunnan Province, China). Based on simple hydraulic jump equations, the erosion into deposition of surge flow is quantified. The erosion patterns and momentum hidden under debris‐flow surges are revealed. The deep erosion pattern means that the apparent debris‐flow surge is merely “the tip of the iceberg,” and there is a large portion underneath. This study proposes a theoretical approach for quantifying the eroded deposition depth and the total momentum carried by debris‐flow surges, which is conducive to a precise risk assessment and mitigation of debris‐flow surges. Key Points The erosion‐deposition propagation of debris flow is confirmed by surge‐depth hydrographs measured at the Jiangjia Ravine, Yunnan Province, China Shallow and deep erosion patterns are revealed by hydraulic jump equations. The debris‐flow surges at the Jiangjia Ravine fall into the deep erosion The destructiveness of debris‐flow surges is quantified by considering the momentum hidden under the surge front and confirmed by field observation

Soil erosion is a key factor in soil quality degradation and carbon balance in arid ecosystems. However, many models ignore the soil erosion process in arid regions, which may lead to limits in our understanding of ecosystem processes in arid regions. In this study, we added the soil erosion process according to field observed data of soil hydrothermal regimes and carbon flux. We validated this coupling version of IBIS (Integrated Biosphere Simulator) and RUSLE (RU–IBIS) by examining four different vegetation types and the carbon budget in the arid region on the Loess Plateau (LP). Our results indicated that the coupling model (RU–IBIS) produced more reliable simulations of the soil water content (with the r from 0.23–0.90 to 0.71–0.97) and evaporation (ET) (the average r was 0.76) and significantly improved the simulation of the leaf area index (LAI) (the average r was 0.95) and net primary production (NPP) (the average r was 0.95). We also conducted sensitivity experiments to determine how soil texture and aerodynamic roughness (Z0m) affect the soil water content. Moreover, it was revealed that specific leaf area (SLA) plays a key role in the simulation of NPP and NEE. Our study suggests that the coupled soil erosion process and parameterization can effectively improve the performance of IBIS in arid regions. These results need to be considered in future Earth system models.

Eolian loess deposits contain valuable information about past climate changes and erosion history in dust source regions. In contrast to the extensive investigations of paleoclimatic implications of Eurasian loess, continental erosion information in the loess deposits has received less attention, particularly on the global or hemispheric scales. The present study combines citrate‐bicarbonate‐dithionite (CBD) magnetic mineral extraction procedures and linear regression of magnetic parameters to analyze Eurasian loess. We find that lithogenic susceptibility of Quaternary loess deposits in Central Asia, Europe and the Chinese Loess Plateau shows synchronous long‐term increases since ∼0.6–0.5 Ma, suggesting intensive glacial erosion and/or river incision to have occurred in the surrounding mountains of dust source regions after the mid‐Pleistocene climate Transition. The dramatic increase in lithogenic susceptibility of Eurasian loess provides new insights into the close relationships between global climate changes and dust source erosion since the late Cenozoic. Plain Language Summary Eolian loess deposits are valuable materials for elucidating the development and mechanisms of dust activities in Eurasia and their links with global climate changes and erosion processes in mountainous areas of dust sources on tectonic and orbital time scales. Continental erosion information retrieved from the Eurasian loess, however, has rarely been reported. A comprehensive analysis of lithogenic magnetic signals in Eurasian loess through mathematical and CBD extraction approaches demonstrates that lithogenic susceptibility of Quaternary loess‐paleosol sequences in Eurasia increased significantly after ∼0.6–0.5 Ma, in coincidence with increasing global ice volume and climatic instability after the mid‐Pleistocene climate Transition (MPT). We suggest that increased ice volume and climate fluctuation amplitudes after the MPT produced vast amounts of fresh Fe‐bearing silicate particles and detrital magnetite in mountainous areas of Eurasia, which can be attributed to a dramatic intensification of glacial erosion and river incision, thereby causing the loess lithogenic susceptibility increase. The results demonstrate that variations in lithogenic magnetic properties of loess deposits can be used to reconstruct the erosional history of main mountains surrounding the dust source regions in Eurasia over geological timescales. Key Points Lithogenic magnetic susceptibility of Quaternary loess deposits in Eurasia increased synchronously after ∼0.6–0.5 Ma Global cooling may account for the increase in lithogenic susceptibility of Eurasian loess Spatial variations of lithogenic susceptibility of Eurasian loess are related to varying distances between the source and the sink region

This paper presents a new hybrid deterministic‐stochastic river morphodynamics numerical modeling approach that integrates a hydrodynamic model (deterministic) with a bed morphodynamic model (deterministic) and a bank erosion model (Markovian stochastic). The hydrodynamic model solves the Shallow Water Equations and the standard k $k$‐ϵ ${\\epsilon}$ model for turbulence closure. Bedload transport is estimated using the Meyer‐Peter and Müller formula, and bed evolution is solved using the Exner equation. The Markovian stochastic bank erosion model uses a new method to evaluate bank erosion risk. The approach was applied to a meander bend cutoff event in the Maiqu River on the Tibetan Plateau. Sixteen different bank‐material critical shear stress cases were considered, representing highly erodible banks (τ‾c=0.1 ${\\overline{\\tau }}_{c}=0.1$ Pa) to resistant banks (τ‾c=15 ${\\overline{\\tau }}_{c}=15$ Pa). Ten statistical realizations were performed for each case with different bank‐material erodibility to obtain ensemble‐averaged results. The flow field and bed evolution in the cutoff channel suggest that the model can successfully simulate bank erosion processes during cutoff channel evolution, and bank topographic irregularities are reasonably captured. A newly introduced calibration parameter is the ratio of mesh size to the coupling period between the bank erosion model and the hydrodynamic and morphodynamic model. Unlike the erosion rate calibration parameters used by traditional bank erosion models, the present model requires estimating the size of a typical slump failure to determine the size of the computational mesh. This new modeling approach enhanced existing tools for fluvial geomorphologists and river engineers focused on bank erosion with real‐world complex geometric features under intricate hydraulic conditions.

Freeze–thaw cycles alter soil properties markedly and cause a subsequent change in soil erosion, however previous studies about freeze–thaw cycles’ influence on soil physical properties were restricted to simulating runoff and soil loss on cropping slopes in cold regions and failed to invoke responses of soils under different degraded conditions to freeze–thaw cycles. This study was designed to compare and quantify the responses of different degraded soils to freeze–thaw cycles in laboratory setting. The soil conditions were divided into five types: original profile, degraded profile, parent profile, deposited profile and compacted surface. Samples were collected from the black soil region in Northeast China and were frozen (− 12 °C for 12 h) and then thawed (8 °C for 12 h) for certain times. Samples without freeze–thaw cycles were treated as control group. Porosity, aggregate mean weight diameter, saturated hydraulic conductivity and water retention curves were tested for control and experimental samples. Results showed that porosity and saturated hydraulic conductivity significantly increased (maximum for degraded profile), while mean weight diameter decreased (maximum for compacted surface) compared with control group. After 30 freeze–thaw cycles, remaining water contents increased in deposited and original profiles, while decreased in compacted surface. Generally, well-structured soils are more difficult to be broken by repeated FTCs. The first freeze–thaw cycle displayed evident influence on soil physical properties under original profile, and at least one threshold of cycle time (between 5 and 20) existed. These findings may help improve understanding the functional mechanism of freeze–thaw cycles on soil erosion processes.

Wave erosion on soil bank slopes has become severe with the long-term operation of the Three Gorges Reservoir; however, the progression of soil bank slope erosion varies in different regions. The influence of the physical parameters of the soil mass on the wave erosion bank slope was investigated using a self-designed and manufactured wave erosion bank slope model test device. Physical model tests were conducted on wave erosion bank slopes comprising six groups with different dry densities and gravel contents to obtain the erosion process of the bank slope under wave action. The results show that the higher the dry density of the soil, the stronger the erosion resistance of the bank slope, and the longer the time required for the bank slope to reach a final steady state; the higher the gravel content, the stronger the erosion resistance of the bank slope. Owing to the protective effect of gravel, the time required for bank slope erosion stability was also shortened. Increasing the dry density or gravel content increased the stable slope angle after bank slope erosion. The wave erosion rate of the bank slope was high at the early stage of the test, and the bank slope erosion of each group was effectively completed within 240 min of the start of the test. The erosion rate of each bank slope under wave action decreased exponentially. Based on this, an empirical equation between the wave frequency and bank slope erosion rate was derived, which can be used to determine the erosion process of a bank slope. This research provides technical support for the prevention and control of erosion on soil bank slopes in the Three Gorges Reservoir area.

Large‐scale photovoltaic (PV) panel installations may significantly affect local hydrological processes, especially in hilly and mountainous regions. However, there is large uncertainty in assessing the hydrological impacts of PV power stations, as the effects of PV panel arrays on overland flow and rill erosion processes in hillslopes have been overlooked. This study quantitatively investigated the interactions between overland flow, soil loss, and rill development influenced by a PV panel array through artificial rainfall experiments on a loess slope with bare surface. The dynamics of overland flow and soil erosion processes in the slope with a four‐panel PV array were compared to a control slope. In the experiments, it was observed that the rill development in the PV slope was largely inhibited. The experiment results demonstrated that, under varying rainfall intensities, the soil erosion mass and the peak erosion rates of the PV slope was 39.7%–64.1% and 38.0%–52.5% less than the control slope, respectively. The reason for this soil erosion mitigation might be that the PV panel array attenuated the impact of rainfall by blocking raindrops, and diminished the overland flow velocity as well as its concentrating movement into rills. These reduced the erosivity of overland flow and decreased soil particle detachment and movement in the slope, which ultimately inhibited rill development and erosion. These findings provide a quantitative basis for accurately assessing the early stage environmental impact of PV power stations, suggesting that large PV installations in arid and semi‐arid regions may reduce initial soil erosion.

Wave erosion is a major geological disaster that can affect the safety of reservoirs. With the long-term operation of reservoirs, wave-based erosion of the soil on reservoir slopes becomes increasingly hazardous. Thus, predicting wave erosion processes is important to ensure successful targeted disaster prevention and control regimes. However, the methods currently used for predicting this erosion are mostly based on empirical equations; thus, their universality is limited. Therefore, in this study, the concepts of wave erosion energy and soil anti-erosion energy were innovatively developed by utilizing the energy conservation method. These concepts were developed using a constructed equation for predicting the erosion rate of a soil bank subject to wave action as well as a model test of a wave erosion bank. The parameters of the prediction equation were solved and the reliability of the equation was verified. The wave climbing height and bank slope during wave erosion were approximately linearly correlated. The higher the wave energy, the larger the functional slope. When the banks were comparatively less steep, the erosion energy of the wave decreased, the anti-erosion energy of the soil increased, and the corresponding bank erosion rate slowed. When the erosion energy was equal to the anti-erosion energy, bank erosion ultimately reached a stable state. In comparing the results of the flume test with the predicted values, the proposed method for predicting the wave erosion rate of soil banks proved reliable.

Channel erosion not only amplifies debris‐flow magnitude and impact but also reshapes local geomorphology. However, the destructive and infrequent nature of debris flows makes in situ monitoring of channel‐bed erosion processes and flow characteristics challenging. Here, we investigate seismic signals for monitoring erosion‐driven geomorphic changes, using data from 18 well‐documented debris flows at Illgraben, Switzerland, between 2019 and 2023. We find that integrated seismically derived impact forces over each event correlate with channel‐bed elevation changes, revealing erosion thresholds. Seismic peak frequencies correlate with absolute channel‐bed elevations at seismic source regions, reflecting changes in wave propagation paths due to erosion. The correlation is evident, with peak frequency shifts exceeding 15 Hz while channel‐bed elevation changes were under 4 m during the 5‐year period. These findings demonstrate the capacity of seismic signals to characterize debris‐flow erosion and track absolute channel‐bed elevations, offering new insights into geomorphic processes.

The spatiotemporal changes in flow hydraulics and energy consumption and their associated soil erosion remain unclear during gully headcut retreat. A simulated scouring experiment was conducted on five headcut plots consisting of upstream area (UA), gully headwall (GH), and gully bed (GB) to elucidate the spatiotemporal changes in flow hydraulic, energy consumption, and soil loss during headcut erosion. The flow velocity at the brink of a headcut increased as a power function of time, whereas the jet velocity entry to the plunge pool and jet shear stress either logarithmically or linearly decreased over time. The jet properties were significantly affected by upstream flow discharge. The Reynolds number, runoff shear stress, and stream power of UA and GB increased as logarithmic or power functions of time, but the Froude number decreased logarithmically over time. The Reynolds number, shear stress, and stream power decreased by 56.0 %, 63.8 %, and 55.9 %, respectively, but the Froude number increased by 7.9 % when flow dropped from UA to GB. The accumulated energy consumption of UA, GH, and GB positions linearly increased with time. In total, 91.12 %–99.90 % of total flow energy was consumed during headcut erosion, of which the gully head accounted for 77.7 % of total energy dissipation, followed by UA (18.3 %), and GB (4.0 %). The soil loss rate of the “UA-GH-GB” system initially rose and then gradually declined and levelled off. The soil loss of UA and GH decreased logarithmically over time, whereas the GB was mainly characterized by sediment deposition. The proportion of soil loss at UA and GH is 11.5 % and 88.5 %, respectively, of which the proportion of deposited sediment on GB reached 3.8 %. The change in soil loss of UA, GH, and GB was significantly affected by flow hydraulic and jet properties. The critical energy consumption initiating soil erosion of UA, GH, and GB is 1.62, 5.79, and 1.64 J s−1, respectively. These results are helpful for deepening the understanding of gully erosion process and hydrodynamic mechanisms and can also provide a scientific basis for the construction of gully erosion model and the design of gully erosion prevention measures.