Foredune notches are increasingly used as a coastal dune management interventions to promote aeolian sediment transport, increase bare sand, and support early successional habitats. Yet understanding of their long-term morphological evolution, persistence, and the extent to which design and wind regime influence outcomes remains limited. This article presents the first systematic, multi-site, multi-year assessment of notch morphological evolution.Aerial imagery spanning periods of 5–12 years was used to quantify changes in area, cross-shore length, longshore width, and slot width for 58 notches. Long-term trends in these parameters were assessed using Theil–Sen regression. Regression models were then used to test the influence of initial constructed morphology, wind regime, and orientation on the observed rates of notch change.Results show that notch evolution is predominantly characterised by contraction. Median notch persistence estimates ranged from approximately 11 to 21 years, but with wide variability between metrics, sites, and regions. Clear regional contrasts were found, with notches in the United Kingdom showing more statistically significant morphological trends and faster rates of contraction than those in the Netherlands, where responses were weaker and more variable. Initial constructed morphology and wind regime explained only modest proportions of variance in evolution rates, indicating the influence of additional site-specific controls that are not captured in the models.Overall, this study shows that notches can remain geomorphologically active over decadal timescales, but their evolution and persistence are highly context dependent. The results highlight the need to consider design and site setting when designing and evaluating notches as long-term dune management interventions.
Mapping of river floodplains and terraces (hereafter river flats) can help mitigate flood hazard, reconstruct paleo river elevations, and map the extent of past and current floodplain deposits. Manually mapping river flats is time consuming, subjective, and not reproducible. Automated processes that efficiently map river flats based on digital elevation models typically rely on the topographic characteristics of the entire watershed, and as a result, the local extent of automatically mapped river flats may deviate from their actual extent. Here, we present a new method that utilizes a local hypsometric analysis instead of watershed-wide topography to map river flats. The method produces a likelihood map that can be used to account for the spatial uncertainty of mapping river flats. The method is capable of constructing a river flats map with recommended values that do not require calibration, but certain input parameters can be tuned by users to fit mapping needs. We test the method by comparing the outputs to hand-mapped river flats in nine Arctic watersheds and FEMA flood hazard maps of the Arkansas River in Colorado and the Russian River in California. Overall, the method produces statistically robust results and performs best in topographies with a clear transition from low relief flats to high relief sloping terrain along the valley margins.
This paper synthesizes regional paleoenvironmental records in order to evaluate the role of fires and associated erosion during two critical Late Quaternary intervals: the last interglacial (MIS 5e, ~129–116 ka), dominated by natural climatic forcing, and the early Holocene (~11–7 ka), when human activity became increasingly significant. The evidence includes micro-charcoal concentrations, speleothem carbon and strontium isotopes, pollen records, lacustrine and alluvial sediments, and archaeological data from the Dead Sea–Jordan Valley system and the Mediterranean hills and coast.Both periods exhibit pronounced peaks in micro-charcoal abundance synchronous with major indicators of vegetation loss and hillslope soil erosion. During MIS 5e, extreme climatic instability was experienced, with intense lightning-ignited wildfires. These fires coincided with soil stripping, elevated δ13C values indicating loss of C3 vegetation, enhanced detrital input to the valleys, and widespread geomorphic instability. A similar but lower-magnitude fire–erosion cascade occurred during the early Holocene, peaking around ~9.5 ka. Although limited anthropogenic burning during the Neolithic cannot be excluded, the spatial extent, synchronicity, and proxy evidence indicate predominantly climatic control, linked to orbital forcing and incursions of dry thunderstorms.Hillslope erosion during both intervals was accompanied by large-scale redeposition of eroded soils in valley bottoms, forming thick alluvial fans and floodplain deposits. During the Neolithic period, such redeposited soils provided favorable conditions for early agriculture and coincided with the concentration of large Neolithic settlements in the Jordan Valley, while contemporaneous abandonment took place in upland areas. It is proposed that Neolithic communities, observing fire-baked clay in recently deposited valley sediments, may have derived the concept of ceramic firing — termed here the ‘natural kiln hypothesis’.
Since it is crucial to understand morphological evolution of gullies correctly before implementing effective gully erosion control measures for areas where gully erosion causes severe sediment removal, this paper aims to explore accurately the relationship between morphological evolution of gullies and their control factors, especially in the compound water-wind erosion region of the Loess Plateau. This study integrates low-altitude unmanned aerial vehicle (UAV) remote sensing with historical topographic maps to monitor gully morphology over long-term timescales. Gully morphological parameters for three catchments were extracted for 2002 and 2021 to develop an erosion volume estimation model, and the relationships between gully evolution and land use types were surveyed. The results show that surface area (SA) was more suitable than length (L) for estimating the gully volume (V), with an effective model is represented as V = 0.911 SA1.22 (R2 = 0.95, n = 127). The average annual linear (Rl) and areal (Ra) retreat rates for these gullies are 0.58 m yr−1 and 4.48 m2 yr−1, respectively. The Rl and Ra of gullies in grassland were 7.9 and 20.07 times higher than those in shrubland, and all newly formed gullies during the study period occurred in grassland areas, indicating that land use was closely associated with gully evolution. The topographic threshold relationship between the upslope drainage catchment area (A) and local slope gradient (S) for 44 gullies is S = 0.124A−0.0425, suggesting a significant influence of piping and subsurface processes on gully initiation and development, while the spatial variability of these thresholds simply underscores the highly unpredictable nature of gully erosion. In this region, shrubland catchments exhibit higher topographic thresholds than grassland catchments, suggesting that shrubland may reduce susceptibility to gully initiation. The results of this study can be used to identify areas susceptible to gully formation and to estimate the contribution of gully erosion to soil loss.
The loess region is characterized by complex geomorphological patterns. This region is prone to frequent earthquakes with serious earthquake-induced loess landslide hazards. The earthquake-induced loess landslides are affected by a variety of factors, including the topography and geomorphology of loess slopes, stratigraphic lithology, dynamic responses, strength and dynamic characteristics of loess, and hydrogeological conditions. Current research on the earthquake-induced loess landslides primarily involves laboratory experiments, physical and numerical simulations, field investigations, and remote sensing and monitoring techniques. The research focuses on the mechanisms, development characteristics, type, distribution, dynamic responses, and stability of the earthquake-induced loess landslides. This paper reviews the current state of both domestic and international research on the earthquake-induced loess landslides, and whose frontier scientific problems in researches in the future are put forward. According to the review and analysis, it is believed that the future frontier scientific problems in loess dynamics should include five aspects: quantitative description of loading effect caused by ground motion on loess, dynamic responding mechanism of loess based on micro interaction of three phases of solid, water and air, quantitative relationship between dynamic response of solid-phase and macro structure strength of loess, coupling influence of earthquake and rainfall on dynamic responding of loess mass, and probability-based assessment of dynamic hazard risk of loess mass. Therefore, we can draw the following conclusions: the integrating multi-scale experimental methods with advanced numerical simulations are essential to unravel the coupled hydro-mechanical mechanisms of loess landslides. A paradigm shift from deterministic to probability-based risk assessment frameworks is urgently needed to address the inherent uncertainties in loess properties and seismic loading for effective hazard mitigation in the Loess Plateau.
Sediment geochemistry in arid source-to-sink systems records source-rock alteration and transport-driven mineral redistribution, yet the extent to which geomorphic setting controls their relative expression remains poorly quantified. We tested this interaction in 89 samples from two eastern Kunlun-Golmud River archives: the valley-confined NCT fluvio-lacustrine sequence (n = 43) and the XGG tributary alluvial-fan sequence (n = 46). CIA was calculated using CaO⁎ = 0.7 × molar Na2O and ranged from 44.34 to 56.97. We compared integrated compositional variables (CIA, SiO2/Al2O3 and LOI; Group A), physical-property variables (d50, <4 μm, CIE L⁎a⁎b⁎ colour and low-frequency magnetic susceptibility; Group B), and depth (Group C) using OLS, PLS, Ridge and CatBoost with contiguous depth-block cross-validation. Across 15 CatBoost runs, Group A outperformed Group B in every paired configuration, with median R2 values of 0.645 and 0.111, respectively. Equal-count Ridge tests confirmed this hierarchy: Group A yielded a median R2 of 0.388, whereas the best of all 20 three-variable Group B subsets reached 0.176. Reassigning LOI to Group B reversed the baseline ordering (0.305 for CIA + SiO2/Al2O3 and 0.379 for B + LOI), identifying LOI as a cross-process link between hydrous alteration products and fine-fraction enrichment. After depth control, K2O in XGG increased with d50 and χLF and decreased with the <4 μm fraction, whereas NCT showed no comparable grain-size coupling. These results show that contrasting geomorphic archives preserve a shared compositional inheritance while imposing setting-specific physical coupling. Replicated fan-to-valley transects, size-fraction mineralogy and magnetic-mineral diagnostics can directly test the proposed routing mechanism.
Anthropogenically-driven shifts in hydroclimatic and wildfire regimes typify fire-prone regions globally, with profound implications for sediment production and transport processes. However, the nature and extent to which past climatic shifts and fire activity have influenced fluvial sediment dynamics over long timescales remains poorly understood, especially in the Mediterranean-climate region of South Africa. This study presents a ca. 2858-year record of fluvial sedimentological change and palaeoecological reconstructions of vegetation (fossil pollen), fire (charcoal) and herbivory (dung spores) from a peatland in the Cape Floristic Region to advance understanding of the linkages between climate, vegetation, fire and geomorphic processes. Analyses of grain-size distribution revealed alternating phases of organic accumulation, punctuated by clastic sediment input. The initiation of clastic sediment pulses supersedes peaks in fire activity and encompasses the period of climatic reorganisation in the region. This highlights the apparent temporal asynchronicity between fire activity and geomorphic responses, where fire may act as a precursor disturbance, with sediment transfer occurring only in response to hydroclimatic forcing. The recovery of pre-disturbance organic sedimentation patterns, especially over the past 200 cal. yr BP, following compounded disturbances, indicates the potential resilience of this wetland. This local-scale resilience likely depends on the capacity of eco-hydro-geomorphic feedbacks to re-establish sediment (dis) connectivity states post-disturbance. By integrating geomorphological and palaeoecological evidence, this study provides novel insights into historical variability in sediment connectivity dynamics in Mediterranean-type fluvial systems. This information is timely, given intensifying human influences, and has implications for catchment management strategies and interpreting wetland evolution trajectories.
Beaches and dunes form vital natural barriers, protecting coastal communities from extreme sea levels. To support coastal management, a geomorphologically-informed understanding of how barriers may be impacted by storm-induced coastal hazards is essential. While storm wave runup can contribute significantly to local extreme sea levels and drive dramatic short- and near-term morphological change to sedimentary coasts, it remains only partly characterised in existing national and regional assessments. This study investigates wave-driven storm impacts at large spatial scales (100–1000 km), at a resolution sufficient to inform local decision making. Using higher resolution national and European datasets, established empirical parameterisations and a simplified barrier morphological evolution model, we predict extreme wave runup and storm impacts on Scotland's wave-dominated sedimentary coasts, at 50 m alongshore resolution. We consider a synthetic storm comprised of 25-year return levels of tides and storm surge, and the 1% exceedance of wave height and period, and predict storm impacts for the present-day, mid- and end-century, under RCP4.5 and RCP8.5. Results show that wave runup contributes on average 38% to extreme sea levels, and over 50% in the most exposed locations under present conditions. Nationally, 416 km (65% of the assessed coast) experience barrier erosion during the synthetic storm event, while 72 km (11%) and 27 km (4%) undergo overwash and inundation, respectively. By 2100 the predicted length of inundated coast approximately doubles to 46 km (7%) under RCP4.5, and 59 km (9%) under RCP8.5. Results reveal strong sub-national variability in storm impacts, identifying clear hotspots with the potential for erosion-enhanced flooding.
Dust storms represent a major natural hazard in arid and semi-arid regions, with significant impacts on climate, ecosystems, and socio-economic systems. The Tengger Desert is widely recognized as an important dust source and transport pathway in Central Asia. However, how surface sediment grain-size characteristics vary across different surface types and affect dust emission along the eastern margin remains poorly understood. To address this issue, surface sediments from five representative surface types (mobile dunes, semi-fixed dunes, fixed dunes, farmland, and alluvial sediments) were collected in December 2024. Grain-size parameters and end-member modeling were applied to analyze sediment characteristics and evaluate dust emission potential. The results show significant differences in sediment grain-size characteristics among surface types (P < 0.05). Dune sediments are dominated by fine and medium sand. Farmland and alluvial sediments are enriched in silt and clay (>20%), with farmland showing the highest content of fine particles. End-member modeling indicates that dune sediments are dominated by saltation end-members (EM2 and EM3, with modal grain sizes ranging from 127.49 to 218.35 μm), whereas farmland and alluvial sediments show higher contributions of the fine-grained end-member (EM1, ranging from 34.83 to 52.44 μm), reflecting contrasting sediment transport and depositional processes. Dust emission flux varies considerably among surface types, with farmland exhibiting the highest value (0.052 kg m−2), followed by alluvial sediments (0.034 kg m−2), whereas semi-fixed dunes show the lowest value (0.016 kg m−2). These findings advance the understanding of aeolian transport processes and dust source identification in desert-margin environments, with important implications for regional dust mitigation and global dust modeling.
High-resolution autonomous underwater vehicle (AUV) surveys offshore southwestern Taiwan reveal bands of sediment-filled troughs on the flat floor of a slope basin at 1279 −1421 m water depth within the accretionary prism. These linear troughs, 1.5−17 m wide and up to 3.5 m deep, are traceable for as long as 3.2 km across the basin floor. These linear features are clearly resolved in high-resolution AUV bathymetry but remain indistinct in ship-based multibeam data. Their alignment with the trace of the Good-Weather Fault identified in multichannel seismic data, together with localized reflector disruption and shallow block deformation observed in Chirp sonar profiles, indicates strong structural control and event-related shallow deformation. Remotely operated vehicle (ROV) observations confirm sidewall slopes generally exceeding 20° and locally reaching up to 60°, and show that the troughs trap fine sediment and anthropogenic debris. The present morphology represents the long-term geomorphic expression of initially formed linear depressions, subsequently modified by sidewall collapse, erosion, and gradual sediment infill over several thousand years. Sedimentation rates and stratigraphic correlation with basin-wide homogenite deposits constrain the initiation of these troughs, by shallow fissuring, to younger than 2.6 kyr BP. The presence of a ∼1.7 kyr BP homogenite layer, together with estimated sedimentation rates, suggests that these troughs initiation may be temporally associated with a prehistoric shaking event around 1.7 kyr BP, followed by prolonged geomorphic modification. These features provide rare morphological evidence of a possible prehistoric megathrust earthquake and highlight the potential of high resolution seafloor mapping for resolving paleoseismic deformation in deep-water subduction-zone settings.
