Earth Surface Processes and Landforms最新文献

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Legacy sediment: A conceptual model and perspective on the role of dams
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-18 DOI: 10.1002/esp.70044
Bridget Livers, Noah P. Snyder
{"title":"Legacy sediment: A conceptual model and perspective on the role of dams","authors":"Bridget Livers,&nbsp;Noah P. Snyder","doi":"10.1002/esp.70044","DOIUrl":"https://doi.org/10.1002/esp.70044","url":null,"abstract":"<p>The term ‘legacy’ usually refers to past human activities that have long since ceased, but contemporary human activities can potentially leave future legacies. While legacy sediment is often defined as having upstream anthropogenic origins, such as from land clearing, infrastructure such as flood control structures and dams can trap sediment, whether naturally or anthropogenically derived, that can persist for centuries or more, thus leaving a legacy of past sedimentation. Dam removal is becoming more common, and accounting of sediment caused by the impoundment is an important component of planning a removal and its impacts. We provide four examples to explore mechanisms of legacy sediment generation: (1) land use changes with no infrastructure or dams, (2) a review of non-dam infrastructure that abstracts water and substantially reduces sediment transport, (3) a case study from the longest-duration geomorphic monitoring (2007 to 2023) of a short (&lt;10 m) dam removed in 2008 and (4) a review of a well-studied tall (&gt;10 m) dam removal. When dams are removed, fluvial processes typically erode sediment in and directly adjacent to newly formed or opened stream channels over short timescales, but inaccessible deposits remain as legacy sediment. We demonstrate that overbank flooding and sedimentation upstream of run-of-river dams can create unrecognised deposits outside of the modern reservoir pool. We further outline how certain dam and other infrastructure characteristics, dam removal style and sediment character can generate persistent legacy sediment and sometimes legacy landforms outside active stream channels where it is unlikely to be excavated by natural geomorphic processes except in the most extreme events. With the increase in dam building and dam removal in various parts of the world, legacy sediment deposits are becoming ubiquitous, with important consequences for river and land management.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/esp.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Surveys conducted a third of a century apart reveal changes to in-stream large wood, riparian vegetation and stream planform in response to management within a UK national park
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-14 DOI: 10.1002/esp.70025
Angela M. Gurnell, Christopher T. Hill, Stephen Tooth
{"title":"Surveys conducted a third of a century apart reveal changes to in-stream large wood, riparian vegetation and stream planform in response to management within a UK national park","authors":"Angela M. Gurnell,&nbsp;Christopher T. Hill,&nbsp;Stephen Tooth","doi":"10.1002/esp.70025","DOIUrl":"https://doi.org/10.1002/esp.70025","url":null,"abstract":"<p>Despite their importance for the structure and biogeomorphological function of river landscapes, riparian trees and wood have long been heavily managed. In 1991, Gregory et al. (1993) undertook a walkover survey of ~60 km of streams within the Lymington River catchment, New Forest, England, including mapping the characteristics of in-stream large wood, riparian vegetation and stream planform. In 2024, the survey was repeated. Before 1991, wood and fallen trees were frequently removed from stream channels to improve drainage and support growth of non-native conifers in plantations. Arterial drains were also cut and linked to realigned, resectioned streams within planted areas. From ~1990, major stream and land management changes were progressively introduced, including a reduction in wood removal from streams, restoration of realigned streams to more natural planforms and smaller channel sizes and clearance of conifers from floodplains to permit recolonisation by native deciduous species.</p><p>Comparative analysis of the 1991 and 2024 survey data reveals &gt;100% increase in the number of wood jams and fallen trees, with fallen trees and the most hydraulically-influential wood jam types increasing by &gt;200%. These increases are particularly associated with sinuous streams draining deciduous woodland. Streams draining coniferous woodland and heath-scrub-lawn-mire show less fallen trees and wood jams and smaller increases between surveys, with particularly low abundances along streams disturbed by conifer clearance and stream restoration. This analysis has quantified the transformation of extended lengths of New Forest streams, revealed the likely degree to which the transformation is attributable to different management actions, and provided insights into possible future trajectories of change.</p><p>Following brief training, the survey is suitable for application by river volunteers and professionals. Repeat surveys in future decades and on other sites can quantify changes to in-stream wood, riparian vegetation and stream planform, providing invaluable insights into the consequences of management actions.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/esp.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Wood jam mobility in a morphologically active river in northern Chilean Patagonia
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-12 DOI: 10.1002/esp.70031
Lorenzo Martini, Alberto Paredes, Karla Sánchez, Andrés Iroumé, Lorenzo Picco
{"title":"Wood jam mobility in a morphologically active river in northern Chilean Patagonia","authors":"Lorenzo Martini,&nbsp;Alberto Paredes,&nbsp;Karla Sánchez,&nbsp;Andrés Iroumé,&nbsp;Lorenzo Picco","doi":"10.1002/esp.70031","DOIUrl":"https://doi.org/10.1002/esp.70031","url":null,"abstract":"<p>Wood is crucial in river systems, influencing both ecological and physical dynamics. Understanding its behaviour in relation to fluvial morphology is essential for effective watershed management, especially after extreme events. The tendency of wood to accumulate into wood jams (WJs) adds complexity, as these dynamics remain challenging to assess. This study explored the relationship between channel morphological changes and WJ mobility in the Blanco River, Chile, which was affected by a volcanic eruption in 2008–2009. The methodological approach involved utilising multi-temporal drone surveys conducted in 2018, 2019 and 2023, over a river segment with an area of 29.5 ha and a length of 2.2 km. First, the characterisation of morphological units, quantification of geomorphic changes, and classification of morphodynamic mechanisms were accomplished using orthophotos and robust Digital Terrain Models (DTM) of Difference (DoD). Then, WJ abundance, spatial arrangement and mobility were derived from their manual delineation over 3 years. Finally, the characteristics of missing, newly formed, and persistent WJs were further analysed in relation to the morphodynamics. The results revealed that the river remains highly active, even 10–15 years post-eruption. From 2018 to 2023, at least 1.43 × 10<sup>5</sup> m<sup>3</sup> of sediment was displaced, yielding a value of 1.21 × 10<sup>5</sup> m<sup>3</sup> km<sup>−2</sup> year<sup>−1</sup>. Most of this displacement was attributed to floodplain erosion from the channel's lateral shifts. WJs covered up to 10% of the study area annually. Mobility rates were 68% and 78% for the periods 2018–2019 and 2019–2023, respectively. In areas with no geomorphic changes, larger, less compact WJs were more likely to persist. However, persistent WJs were also associated with bank erosion and sediment deposition over bars. In contrast, missing or newly formed WJs tended to be smaller, more compact and were primarily linked to significant erosional and depositional processes.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/esp.70031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Modelling river and floodplain evolution using physics-based and reduced-complexity approaches
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-12 DOI: 10.1002/esp.70008
Andrew P. Nicholas
{"title":"Modelling river and floodplain evolution using physics-based and reduced-complexity approaches","authors":"Andrew P. Nicholas","doi":"10.1002/esp.70008","DOIUrl":"https://doi.org/10.1002/esp.70008","url":null,"abstract":"<p>Models of river-floodplain evolution have previously been classified as adopting either <i>physics-based</i> or <i>reduced-complexity</i> approaches, with the latter presumed to afford a weaker representation of fluvial processes and dynamics. Results are presented herein that enable the first direct comparison of two such approaches within a single fluvial morphodynamic modelling framework. This is achieved using a new morphodynamic model that can be implemented using two alternative hydrodynamic solvers, while all other model components are unchanged. The two solvers are a momentum conserving (MC) Godunov-type finite volume scheme; and an inertial formulation (IF) of the shallow water equations, which neglects momentum transport. Simulations reported herein demonstrate that the two modelling approaches can produce channels characterised by very similar morphology and process rates. Moreover, both solvers exhibit consistent behaviour that illustrates the key role of lateral dynamics (driven by both bank erosion and other mechanisms of floodplain reworking) as a control river channel pattern. Overall, the IF solver is characterised by greater sensitivity to changes in model parameter values and, for some parameterisations, may promote channels with unrealistic planform morphology. Moreover, the neglect of momentum transport by the IF solver restricts its capacity to represent flow acceleration over bar tops, which has implications for its ability to simulate bar-driven braiding and low sinuosity braided anabranches. Despite this, the simpler IF solver is capable of simulating the evolution of meandering channels (and their floodplains) using coarse model grids, due to its representation of streamline curvature effects on sediment transport direction. The resulting reduction in computational cost associated with implementing the IF solver suggests that such reduced-complexity approaches may be particularly suitable for use in simulating the long-term (millennial) evolution of meandering river floodplains, perhaps more so than braided channels, which have often been the focus of reduced-complexity modelling studies in the past.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/esp.70008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Cirques in the eastern Kunlun Mountains, NE Tibetan Plateau and their links to climatic and non-climatic factors
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-12 DOI: 10.1002/esp.70034
Qian Zhang, Han Meng, Yong Sun, Ninglian Wang, Chaolu Yi, Li Zhang, Lupeng Yu, Yubin Wu
{"title":"Cirques in the eastern Kunlun Mountains, NE Tibetan Plateau and their links to climatic and non-climatic factors","authors":"Qian Zhang,&nbsp;Han Meng,&nbsp;Yong Sun,&nbsp;Ninglian Wang,&nbsp;Chaolu Yi,&nbsp;Li Zhang,&nbsp;Lupeng Yu,&nbsp;Yubin Wu","doi":"10.1002/esp.70034","DOIUrl":"https://doi.org/10.1002/esp.70034","url":null,"abstract":"<p>Cirque metrics are widely used to deduce palaeoclimate conditions, with extensive research in the alpine regions of High Mountain Asia (HMA). Some debates remain regarding the relationship between cirque morphology and climate/topography and a detailed study is needed to deepen the knowledge of cirque development. This study delineated and analysed 375 cirques in the eastern Kunlun Mountains, northeastern Tibetan Plateau. Results show that cirque area and development degree decrease from west to east. Cirques and modern glaciers predominantly face north. In an east–west contrast, more cirques face west, with lower cirque floor altitude (CFA) than those facing east, highlighting the effect of the east Asian monsoon (EAM). The eastward decline in CFA in the eastern Kunlun Mountains implies that the palaeoprecipitation increases eastward, highlighting the dominant role of the EAM on glaciation during the last glacial period. The lower aspect asymmetry of the cirques than that of the modern glaciers implies greater glacial coverage during the last glacial period than today. By comparing the results across the HMA, it is suggested that cirque density, specific area, size, floor altitude and aspect asymmetry exhibit no distinct correlation with annual temperature, precipitation, altitude and bedrock resistance. Cirque development depends on the relative efficacy of glacial erosion, which is jointly controlled by local climate, topography and bedrock type, which may be regionally diverse. This may be an explanation for the inconsistencies in the relationships between cirque metrics and climate in different regions.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The unrepeatable river: Exploring chaotic variability in laboratory channels
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-12 DOI: 10.1002/esp.70027
David L. Adams, Marwan A. Hassan, Sarah Davidson
{"title":"The unrepeatable river: Exploring chaotic variability in laboratory channels","authors":"David L. Adams,&nbsp;Marwan A. Hassan,&nbsp;Sarah Davidson","doi":"10.1002/esp.70027","DOIUrl":"https://doi.org/10.1002/esp.70027","url":null,"abstract":"<p>Experimental work relies on the assumption that, under controlled conditions, repeat trials will yield consistent outcomes. This assumption is crucial in geomorphology, as both a theoretical and applied science, yet it is rarely examined directly. We investigated the repeatability of channel forms by conducting 14 trials using a gravel-bed stream table. Analyses of morphology and hydraulics using simple statistics, dimensional reduction techniques and hierarchical clustering were used to quantify similarities and differences between outcomes. Average channel form was consistent across all trials, but practically, irreducible variations in initial conditions led to divergent outcomes through chaotic dynamics. Notably, two distinct channel outcomes were observed, resembling attractor states, relating to the presence or absence of an avulsion. The results indicate that even under well-controlled conditions, repeatability is not guaranteed in physical models. The findings prompt a re-framing of how experimental certainty and repeatability are defined in practice. Conducting repeated trials may mitigate the confounding effects of variability, but the optimal number of trials remains unclear and is likely case-specific. We suggest that future research incorporate repetitions and explore probabilistic approaches to presenting results. Embracing and quantifying this variability can enhance the robustness of physical models and provide deeper insights into channel dynamics.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/esp.70027","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
UAV and photogrammetric techniques to study shoreline changes in the high Arctic as exemplified by the Kaffiøyra region, Svalbard
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-11 DOI: 10.1002/esp.70037
Kamil Czarnecki, Ireneusz Sobota
{"title":"UAV and photogrammetric techniques to study shoreline changes in the high Arctic as exemplified by the Kaffiøyra region, Svalbard","authors":"Kamil Czarnecki,&nbsp;Ireneusz Sobota","doi":"10.1002/esp.70037","DOIUrl":"https://doi.org/10.1002/esp.70037","url":null,"abstract":"<p>High-latitude coasts are among many polar ecosystems vulnerable to global climate change. This paper presents research results on coastline changes in Kaffiøyra, Svalbard (High Arctic). Archival aerial photographs and satellite imagery (1966, 1990, 2017) were used, and field surveys (by UAVs) were carried out in 2021–22 to create high-resolution digital terrain models (pix ~ 5 cm). The Area Of Interest (AOI) covered ~1.5 km<sup>2</sup> and was divided into four main zones of different characteristics (mouth of the river, beach, bay and sand spit). Remote sensing methods were used to determine the directions of changes in the Kaffiøyra coastline and to indicate the main factors affecting the deposition or erosion of sediments. With the support of a UAV kit with a GNSS receiver, using photogrammetric software, models, with precise and low error rates, were obtained depicting the state of the Arctic environment. The average rate of coastline retreat in the adopted AOI ranged from −0.24 ± 0.16 to 0.70 ± 0.16 m yr<sup>−1</sup> (1966–2021), but in the selected period: −0.32 ± 0.57 to 0.19 ± 0.57 (1966–1990), −0.38 ± 0.40 to 1.10 ± 0.40 (1990–2017); −0.27 ± 0.47 to 1.33 ± 0.47 (2017–2021). The study described the direct factors (coastal currents, tides, hydrographic network) and indirect factors (meteorological conditions and recession of Kaffiøyra glaciers) but focused on the morphometric transformation of the shoreline. In this study, the authors sought to explain the causes of the changes that are occurring in the polar environment. They performed the analysis under the very specific meteorological and topographical conditions of the Kaffiøyra lowland, discovering and closing the spatial gaps of coastal research in the Arctic. The results were compared with different locations on Spitsbergen, where the reasons for these changes were quite different.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The impact of river capture on fluvial terraces and bedrock incision
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-09 DOI: 10.1002/esp.70035
Sean F. Gallen, Karl W. Wegmann
{"title":"The impact of river capture on fluvial terraces and bedrock incision","authors":"Sean F. Gallen,&nbsp;Karl W. Wegmann","doi":"10.1002/esp.70035","DOIUrl":"https://doi.org/10.1002/esp.70035","url":null,"abstract":"<p>River terraces are commonly used to infer climate and tectonic histories. Yet, it is increasingly recognised that other processes, such as river capture, can affect river terrace genesis and incision rates and patterns. In this study, we conduct a field-based investigation of river terrace sequences along the Kolokithas and Varitis Rivers in central Crete, Greece, that share a confluence and preserve geomorphic evidence for the recent capture of the Kolokithas headwaters by the Varitis. We use digital topographic analysis, mapping, and optically stimulated luminescence (OSL) geochronology to quantify the river terrace and bedrock incision response to river capture. Topographic analysis indicates the Varitis captured ~30 km<sup>2</sup> of drainage area from the Kolokithas. We find differences in terrace characteristics, number of terraces, and incision rates and patterns on the adjacent valleys. The Kolokithas has four terrace levels, and the Varitis has five. All terraces are strath terraces, except for the oldest on the Kolokithas, a ~8 m thick fill terrace that starkly contrasts the time-equivalent ~1–2 m thick strath terrace on the Varitis. Relative and absolute age control suggests three Pleistocene terraces were emplaced during cooler climate intervals, and two Holocene terraces are perhaps because of anthropogenic disturbances. The incision patterns differ on each valley, with generally more incision upstream on the Varitis relative to the Kolokithas. Incision rates on the Varitis are roughly twice as high as on the Kolokithas, but the average incision rate of both valleys combined is comparable to coastal rock uplift rates derived from marine terraces. Collectively, our results suggest that fluvial systems are sensitive to climate and tectonic processes even when affected by geomorphic disturbances, like river capture and beheading. However, care must be taken when interpreting river terraces as direct records of climate and tectonic processes, particularly when working on a single river valley.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Rheology of debris flows: Insights from experiments with coarse-grained matrix
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-09 DOI: 10.1002/esp.6069
Taiqiang Yang, Yong Li, Xiaojun Guo, Kun Wang, Jun Zhang, Junyao Luo, Jingjing Liu
{"title":"Rheology of debris flows: Insights from experiments with coarse-grained matrix","authors":"Taiqiang Yang,&nbsp;Yong Li,&nbsp;Xiaojun Guo,&nbsp;Kun Wang,&nbsp;Jun Zhang,&nbsp;Junyao Luo,&nbsp;Jingjing Liu","doi":"10.1002/esp.6069","DOIUrl":"https://doi.org/10.1002/esp.6069","url":null,"abstract":"<p>Debris flow is characterized by a heterogeneous mixture of water and sediment with varying rheology. The granular effects on rheology are usually attributed to the bulk concentration of solids without considering the variability of granular configuration, as signified in the grain size distribution (GSD). In this work, the GSD effects on debris flow rheological properties were explored using the parameters <i>μ</i> and <i>D</i><sub>c</sub> derived from a unified GSD function, <i>P</i>(<i>D</i>) ~ <i>D</i><sup><i>-μ</i></sup> exp(-<i>D</i>/<i>D</i><sub>c</sub>), that are widely applicable for debris flow materials. Compared with other experiments using artificial fine-grained slurry (with grain size &lt;2 mm) at a given solid volume concentration (<i>C</i><sub>v</sub>), the realistic coarse-grained matrix (up to 10 mm) of fresh debris flows was used for the experimentation, under shear rate up to 40 (s<sup>−1</sup>) as in natural conditions. The results show that the flow can be categorized as Herschel-Bulkley (HB) fluid, with an average consistency index of 0.45, signifying the shear thinning effect. The yield stress and effective viscosity exhibit a power-law with <i>μ</i> and an exponential relationship with <i>D</i><sub>c</sub>, revealing the interlock between fine and coarse grains. Then, a modified HB model was proposed using the GSD parameters to specify the granular effects and explain the velocity fluctuation of debris flow surges. This work represents the first attempt to express rheological properties as a function of the unified GSD parameters and is potentially instrumental in formulating debris flow dynamics incorporating granular effects.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Grid independence studies applied to a field-scale computational fluid dynamic (CFD) model using the detached eddy simulation (DES) technique along a reach of the Colorado River in Marble Canyon
IF 2.8 3区 地球科学
Earth Surface Processes and Landforms Pub Date : 2025-03-08 DOI: 10.1002/esp.70030
Rosa E. España, Laura V. Alvarez, Jayanga T. Samarasinghe
{"title":"Grid independence studies applied to a field-scale computational fluid dynamic (CFD) model using the detached eddy simulation (DES) technique along a reach of the Colorado River in Marble Canyon","authors":"Rosa E. España,&nbsp;Laura V. Alvarez,&nbsp;Jayanga T. Samarasinghe","doi":"10.1002/esp.70030","DOIUrl":"https://doi.org/10.1002/esp.70030","url":null,"abstract":"<p>Grid independence studies have emerged as essential methodological frameworks for comprehending the impact of domain resolution on simulating anisotropic turbulence at the river-reach scale using large eddy simulation models. This study proposes a methodology to assess the loss of information in turbulent flow patterns when coarsening the computational domain, examined in a 1-km transect of the Colorado River along Marble Canyon. Seven computational domain resolutions are explored to analyse the sensitivity of turbulent flow to spatial resolution changes, utilizing the turbulent kinetic energy (TKE) spectrum technique and spatiotemporal analysis of eddy structures via statistical metrics such as root mean square error (RMSE), Kullback-Leibler (KL) divergence, Nash-Sutcliffe model efficiency coefficient (NSE), wavelet power spectrum and grid convergence index (GCI). Based on physical principles and statistics, these metrics quantify information loss and assess domain resolutions. A computational fluid dynamic (CFD) model is developed by employing the detached eddy simulation (DES) technique, with boundary condition (BC) integrating the rough wall extension of the Spallart-Allmaras model in cells near the bed. Evaluation of domain resolutions aims to identify grid cell sizes capturing flow behaviour and hydraulic characteristics, including primary and secondary flows, return currents, shear layers and primary and secondary eddies. The study observes an increase in data representation of the TKE spectrum with finer spatial domain resolution. Additionally, surface analysis, conducted via RMSE, KL and NSE metrics, identifies specific areas within the flow field showing high sensitivity to refining the grid cell sizes.</p>","PeriodicalId":11408,"journal":{"name":"Earth Surface Processes and Landforms","volume":"50 3","pages":""},"PeriodicalIF":2.8,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143581444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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