Tributary Channels Research Articles

The return of the Iváň Canyon, a large Neogene canyon in the Alpine-Carpathian Foredeep

The submarine Iváň Canyon oriented parallel along the front of the Western Carpathian fold and thrust belt and the foreland of the Bohemian Massif has been studied on numerous 2D seismic sections and available borehole cores. The canyon can be followed over the distance of more than 75 km indented within the sedimentary infill of the Alpine-Carpathian Foredeep from Lower Austria into the Czech Republic. Seismic data reveal up to 600 m depth of the canyon and its width of 2.5–6 km. The canyon is characterized by a low sinuosity planform architecture with an axial main channel and several tributary channels of varying dimensions. Six seismic facies were identified, separated by three erosional surfaces, which led to recognition of seven evolutional stages of the canyon.Facies analysis, clast composition and heavy mineral spectra indicate derivation from a siliciclastic source area, cannibalization of an older basin infill and an important role of sustained low-density turbidity currents in transport and deposition. The strontium isotope stratigraphy data supported by microbiostratigraphy and by foraminiferal δ18O and δ13C isotope analysis confirmed, that the depositional history of the canyon infill lasted from the upper Burdigalian/Langhian boundary up to the lower Serravalian, with the dominance of Langhian deposits in its infill.The formation and depositional history of the canyon is explained by the complicated structural and depositional history of the Alpine-Carpathian Foreland basin during the lower/middle Miocene transition and middle Miocene (Langhian) with a dominant role of tectonic subsidence and basin re-configuration accompanied by eustatic sea-level fluctuations. The Iváň Canyon as axial channel developed in the elongate foreland basin reveals several differences if compared to typical ancient submarine canyons in the passive margin settings.

Lymphatic Malformation of Inguinal region in an adult: A Case Report.

Lymphatic malformation are most commonly located in regions of confluence of major lymphatic channels, including the neck ( 75%), axilla ( 20%), mediastinum, retroperitoneum, pelvis and groin. We are reporting here a rare case in which a 35year old female presented with swelling over right groin and thigh. A provisional diagnosis was made on radiological investigations. Wide Local Excision with Tensor Fascia Lata Flap Reconstruction with Split Skin Graft was done and the diagnosis was confirmed on histopathology and immunohistochemistry. Keywords: Lymphatic malformation, Acquired Progressive Lymphangioma, Benign lymphangioendothelioma

Long-term hillslope erosion and landslide–channel coupling in the area of the catastrophic Wenchuan earthquake

Approximately 200,000 landslides were triggered by the 2008 Wenchuan earthquake and subsequent strong rainfall events, and the amount of landslide sediment delivered to the channels within catchments depended on the amount of landslide debris generated by the earthquake and the amount of post-earthquake rainfall. To better understand long-term hillslope erosion and the long-term changes in landslide–channel coupling, this study quantifies the coupling degree of landslide–channel by defining a landslide-channel coupling index (LCCI) and estimates the long-term hillslope erosion driven by landslides within 12 debris flow basins. We track landslide activity using multiyear imagery from 2008 to 2019, and the landslide ratio, landslide new regeneration ratio, and landslide reactivated ratio indicate that the overall landslide activity decayed following the Wenchuan earthquake. The calculation results of the coupling index illustrate that the coupling degree of landslide–channel in the study area follows a power law trend of decay over time. However, due to the influence of landslide activity, the coupling index decreased significantly in the first 5 years after the Wenchuan earthquake and then decreased slowly. The hillslope erosion driven by landslides is estimated using a conservative statistical model. The result shows that the landslide-driven hillslope erosion has decayed following a power law, and elevated levels of erosion may last for an unexpectedly long period. In addition, the landslide–channel coupling degree affects the movement of landslide sediment to channels. While the coupling degree of landslide–channel and the amount of landslide sediment supplied to the channels have decreased significantly in recent years, abundant landslide sediment could still be delivered to the channels when strong rainfall occurs in this region. Furthermore, a considerable amount of sediment appears to remain within the tributary channels and trunk channels, which means the activity of debris flow may last longer period than hillslope erosion.

Hydrological modelling applied to flooding assessment in the urban coastal city in Brazil

The urban region of many coastal municipalities is marked by the growing process of urbanization of its marine river plain and presents great challenges related to the drainage of rainwater. This study seeks to verify the influence of the flood wave, coming from the upper part of the Macaé River hydrographic basin, in the flooding of the urban area, using MOHID platform, Land module, for the hydrodynamic simulation. The municipality of Macaé, located in the north of Rio de Janeiro (Brazil), has a dense network of tributary channels, built to drain more quickly the waters that accumulate in the floodplains during the rainy seasons. The current configuration of this system is insufficient to reconcile the current land use and runoff, and the floods impose several economic losses. Given this scenario, the Hydrographic Basin Committee of the region, through its Water Resources Plan, recommended studies on the theme, pointing out the need for a more detailed topographic description. The results of the model were compared with a rain that occurred in March 2018, which caused flooding in various points of the urban area. The methodology used can be applied in other municipalities with the same need.

Geospatial and fluvio-geomorphological investigation of confluence dynamics of river Raidak within Himalayan foreland basin, India

ABSTRACT Confluence of river channels plays a significant role in channel avulsion, flood plain evolution and dynamics of the fluvial system. The principal objectives of the present study are (i) to analyze the direction and degree of confluence shifting through the recent past (1955–2020) by applying geospatial techniques and (ii) to find out the probable causes of confluence dynamics of the Raidak river system within quaternary geological sites of a Himalayan foreland basin in West Bengal, India, applying fluvio-geomorphological and sedimentary bank facies. Modified Normalized Difference Water Index method is also used. The result shows that the Raidak-Sankosh confluence (RSC) shifted by 9.94 km of the total distance between 1955 and 2020, whereas Raidak-I-Torsa confluence (RTC) has shifted 4.29 km overall distance during the same period. Both confluences were shifted toward the south and south-east directions. Total erosion and accretion area at the proximity of RSC and RTC has been registered as 40.1 sq km and 47.57 sq km and 39.67 sq km and 37.99 sq km, respectively, for the 65-year period. The key factors of confluence dynamics are regular flood events and channel avulsion, non-cohesive bank materials and huge channel bed sedimentation with multiple bars.

Insights into the geomorphology of the Ceará Basin, Brazil, by combining seismic attributes, machine learning, and rock-physics analyses

Abstract We utilize 3D seismic data and robust rock-physics models, combined with a well dataset, to investigate the subsurface of the Mundaú sub-basin, Brazil. Seismic attributes analysis and unsupervised machine-learning approaches were able to produce high-resolution images to allow the mapping of the 3D geometry of ancient geomorphological features across stratigraphic levels, from the Albian to the Turonian interval. Significant deep-water elements were identified using seismic attributes and machine-learning techniques (i.e. channel complex, point bars, feeder channels, faults, depocentres, dendritic lobes, smaller channels and distributaries). In addition, the petrophysical analysis enhanced the subsurface characterization by employing a deep convolutional network that allowed S-wave modelling and synthetic seismic generation. The well-log data analysis validated interpretation of sand-prone deposits; in addition, the rock-physics modelling provided insight into the deposited lithologies. After the petrophysical analysis, seismic facies classification was performed using machine-learning techniques, including self-organizing maps and independent component analysis, which provided valuable insights into the geomorphology of this under-researched basin. The enhancement of seismic and petrophysical data with machine learning proves to be a useful technique for better characterizing this basin. This approach may be used on similar frontier hydrocarbon basins to help de-risk petroleum exploration.

Numerical Simulation of Turbulent Flow in Bends and Confluences Considering Free Surface Changes Using the Volume of Fluid Method

The impact of secondary flows on the flow velocity in open channel bends and confluences was simulated using three-dimensional (3D) numerical models. The Reynolds-averaged Navier–Stokes equation system was utilized as the governing equations and two different turbulence models were employed in this study: the standard k-ε model and the realizable k–ε model. In a recent study by the authors, the rigid lid approach was used, which does not allow for vertical displacement of the water surface. In this study, the simulation of free surface displacements was simulated using the volume of fluid free-surface tracking method. The numerical models were evaluated and validated by using the experimental data of a sharply curved channel and a confluent channel. The accuracies of the two turbulence models were evaluated and discussed. This study found that both models can satisfactorily reproduce the experimental data. However, the standard k–ε model performed better for the curved channel case while the Realizable k–ε model performed better for the confluent channel case.

Geomorphological evolution of the Group I fluvial system, AX field, Malay Basin

The AX Field is located 167km off NNE Kerteh, Terengganu of Peninsular Malaysia, southwest of Malay Basin. This study is focused on the 3D seismic analysis of the Lower Miocene fluvio-deltaic Group I. The objective of the study is to evaluate the geomorphological evolution of fluvial succession and interpret the possible intra-basinal and extra-basinal controls on the fluvial evolution. One hundred strata slices were generated in order to evaluate the evolution of the fluvial systems within the Group I interval. Seismic attributes such as Root Mean Square (RMS), sweetness and spectral decomposition were computed to map channel geomorphology. Different fluvial styles were identified in the different parts of the study area. Variation of fluvial style were identified within the Group I interval including the low sinuosity system with tributary channels, high sinuosity system with broad meander belt and braided system. Fluvial channel imaged within the studied interval can be divided into six (6) stages based on the channel morphology. Stage 1 (1875 – 1810 ms), the oldest stage, displays high sinuosity channels. Braided system associated with coal deposition were imaged in Stage 2 (1810 – 1765 ms). During stage 3 (1765 – 1710 ms), the fluvial system is characterized by low to moderate sinuosity channel features that varies in scale and geometry. Stage 4 (1710 – 1675 ms) display fluvial style characterized by low sinuosity-to-straight system with tributary channels. Stage 5 (1675 – 1615 ms) is represented by high sinuosity fluvial system with broad meander belt and point bar. During Stage 6 (1615-1536 ms) the fluvial system displays moderate-to-high sinuosity. The high sinuosity system in period 6 exhibit well-defined meander scroll bar morphology that reveals the extension and translation course of the fluvial system.

Tributary channel networks formed by depositional processes

Tributary channel networks formed by depositional processes

Risk Assessment of Debris Flows in Small Watersheds on the Northeast Margin of Qinghai-Tibet Plateau—A Case Study of Zhujiagou Watershed

Abstract In the Qinghai-Tibet Plateau, fractures and fault zones have developed in this area, where earthquakes and extreme rainfall frequently induce debris flow disasters, which seriously threaten the safety of the people and properties. In this study, Zhujiagou, Minxian County, Gansu Province in China, has a typical debris flow channel in a small watershed on the northeastern edge of the Qinghai-Tibet Plateau, which has been used as the case study for risk assessment. A debris flow-risk assessment method has been developed in this study. The fusion algorithm of entropy weight and coefficient of variation has been used to evaluate the susceptibility of debris flow in each tributary channel in the watershed. Further, numerical simulation of the debris flow events at the main channel and at the high-prone debris flow tributary channel has been carried out. The “7.18” Zhujiagou debris flow event has been used to verify that the accuracy of the numerical simulation is higher than 74.12%. This method has been applied to design the Zhujiagou debris flow-risk zoning under extreme rainfall conditions, aimed at forming a set of debris flow-risk evaluation system suitable for this type of small watershed. The results show that the peak single-width clear water flow at the mouth of the channel, the length of the channel, and the shallow surface rock formation are the main factors influencing the susceptibility of debris flow. The main tributaries of the watershed are Hagu channel, Zhuling channel, Songshu channel, and Langjia channel which are all high-prone debris flow channels. The Zhujiagou debris flow accumulation fan under the designed 1% rainfall frequency will block the Taohe, which will threaten the safety of the residents and properties near the channel, at the mouth of the channel and in the urban area on the opposite bank of the Taohe. Compared with Hagugou, Zhulinggou, and Songshugou, the low-risk area is Langjiagou. The research results of this study can be used for evaluation methods and as a basis for preventing debris flow disasters on the northeastern edge of the Qinghai-Tibet Plateau.

Reservoir Forming Conditions and Enrichment Law of Tight Sandstone Gas in Upper Paleozoic in Ordos Basin

With the popularization of natural gas and the requirement of environmental protection, the development and utilization of natural gas are particularly important. The status of natural gas in China’s oil and gas exploration and development is constantly improving, and the country pays more and more attention to the exploitation and utilization of natural gas. The tight sandstone of Upper Paleozoic in Ordos Basin has the characteristics of low porosity, low permeability, and large area of concealed gas reservoirs. With the increasing demand for natural gas in China, systematic analysis and research on the geological conditions and enrichment law of large area gas reservoirs of tight sandstone of Upper Paleozoic in Ordos Basin to guide exploration and production also pose a great challenge to the current level of natural gas exploration and development in China. In order to solve this problem, this paper takes the Upper Paleozoic tight sandstone in Hangjinqi area in the north of Ordos Basin as the research object, summarizes the natural gas accumulation conditions of tight sandstone according to the geological characteristics of Ordos Basin, determines the main control factors of gas accumulation by superposition method in combination with the distribution characteristics of natural gas, simulates the dynamic process of gas accumulation, establishes the gas accumulation model, analyzes the conditions of gas accumulation and enrichment by statistical methods, summarizes the accumulation and enrichment rules of natural gas, and predicts the favorable exploration areas for natural gas. The results show that the relationship between hydrocarbon source rocks, traps, migration and transportation, and other reservoir-forming conditions and the distribution characteristics of natural gas is summarized, and the main controlling factors of reservoir-forming are determined by superposition method. We simulate the evolution process of faults, strata, oil, gas, and water flows in the study area and establish the dynamic reservoir-forming process of natural gas. By combining the reserve data with the reservoir source distance, reservoir facies type, and gas filling times, the reservoir-forming and enrichment conditions are studied by statistical analysis method, and the reservoir-forming and enrichment rules are summarized by combining the main controlling factors. The enrichment of natural gas is controlled by the development degree of source rocks, favorable tight sandstone combination, confluence channel, and local structure. According to the law of accumulation and enrichment, the division standards of favorable areas in different horizons are established, and the favorable exploration areas in the study area are predicted. The results provide theoretical data support for natural gas exploration in the study area.

Effects of hydropower management on the sediment composition and metabolism of a small Alpine lake

The ecological equilibrium of water reservoirs may differ from that of natural lakes. We questioned this difference by analysing the sediments of a small oligotrophic Alpine lake, whose management was modified for hydroelectric production since 1976. Corne Lake is formed by a shallow depression connected to a deep depression. The hydropower management induced water level fluctuations (+2 m in summer; −8 m in winter) that emptied the shallow depression during the winter months and promoted the erosion of littoral soils and tributary channel sediment and the sedimentation in the deep depression. The sediment of the original lake was a low-density organic mud. The sediment composition varied according to 3 phases, which chronology is debated. During a first phase we measured an increase in the ratio of Diatom/Chrysophycea and bioavailable P, as well as a decrease in the C/N ratio and bulk radiocarbon age of the sediment, suggesting a trophic surge. A second phase was characterised by a high rate of mineral sedimentation, an increase of benthic diatom genera in the deep depression of the lake and acidophilic diatoms in the shallow depression. In the third phase covering the last upper cm of the cores, the sediment tended to return to its initial composition, but the algae community differed from its initial state. We suggest that the management of Alpine lakes as reservoirs induce long-term ecological changes in relation to water level fluctuations and littoral habitats degradation.

Petrogenesis of the Paleoproterozoic Näränkävaara layered intrusion, northern Finland, Part II: U-Pb ID-TIMS age and Sm-Nd isotope systematics

Several mafic-ultramafic layered intrusions were emplaced in the NE Fennoscandian Shield during a magmatic episode at 2.44 Ga. The Paleoproterozoic Näränkävaara layered intrusion, northern Finland, is one of the largest ultramafic bodies in the Fennoscandian Shield, with a surface area of 25 km x 5 km and a magmatic stratigraphic thickness of ~3 km. The intrusion comprises a 1.3 km-thick peridotitic–dioritic layered series (2436 ± 5 Ma) with two peridotitic reversals, and a 1.5–2 km thick basal dunite series mainly composed of olivine adcumulates (dated here). The intrusion has been studied since the 1960’s, but several questions regarding its structure and petrogenesis remain. The basal dunite shows several lithological features typical of komatiitic rather than intrusive olivine cumulates; namely, >1 km-thick “extreme” olivine adcumulates, some showing textures with bimodal grain sizes, oscillating variations in Mg# with stratigraphic height, and poikilitic chromite. With Archean greenstone belts nearby, it was previously hypothesized that the basal dunite series could represent an Archean komatiitic wall rock to the Paleoproterozoic layered series. However, our new U-Pb ID-TIMS baddeleyite age of 2441.7 ± 0.9 Ma for the basal dunite series shows that the basal dunite and layered series of the Näränkävaara intrusion are co-genetic. New whole-rock Sm-Nd isotope data from key stratigraphic units (initial εNd at 2440 Ma of -3.5 to -1.7) indicate that the intrusion was constructed from repeated emplacement of LREE-enriched high-MgO basaltic magmas that were mantle-derived and contaminated by crust, similarly to other Fennoscandian 2.44 Ga intrusions. The parental magmas show similar compositions regardless of stratigraphic position, suggesting that most wall rock contamination and homogenization had occurred before emplacement, with in situ contamination being a relatively minor process. The open-system features of the basal dunite suggest that it may have formed (at least partly) as a feeder channel cumulate, possibly related to the ~100 km long Koillismaa-Näränkävaara Layered Igneous Complex. The Näränkävaara parental magmas show variably depleted metal ratios and could have potential for orthomagmatic mineral deposits, given the availability of S-rich wall rocks.

Analysis of Storage Effects in the Recirculation Zone Based on the Junction Angle of Channel Confluence

In this study, numerical simulations using the Environmental Fluid Dynamics Code model were conducted to elucidate the effects of flow structures in the recirculation zone on solute storage based on the junction angle. Numerical simulations were performed at a junction angle of 30° to 90° with a momentum flux ratio of 1.62. The simulation results revealed that an increase in the junction angle caused the recirculation zone length and width to increase and strengthened the development of helical motion. The helical motion increased the vertical gradient of the mixing layer and the mixing metric of the dosage curves. The recirculation zone accumulated the solute as a storage zone, which formed a long tail in the concentration curves. The interaction between the helical motion and recirculation zone affected the transverse mixing, such that the transverse dispersion had a positive relationship with the helical motion intensity and a negative relationship with the recirculation zone size. Transverse mixing exhibited an inverse relationship with the mass exchange rate of the recirculation zone. These results indicate that the transverse dispersion is replaced by mixing due to strongly developed storage zones.

Middle Ordovician mass‐transport deposits from western Inner Mongolia, China: Mechanisms and implications for basin evolution

AbstractSubaqueous mass‐transport processes are one of the mechanisms for transport of sediment into the deep sea. Internal structures and depositional processes of carbonate mass‐transport deposits are relatively poorly understood relative to siliciclastic facies due to their comparative paucity in the rock record. A variety of carbonate mass‐transport deposits, including slumps, debrites and deep‐channel‐confined density flow deposits, occur in Middle–Upper Ordovician slope deposits in western Inner Mongolia (Wuhai), China. These provide a rare opportunity to illustrate the emplacement history of carbonate mass‐transport deposits at the outcrop scale. The slumps and debrites host remarkable folds, chaotic beds and imbricated beds that reflect differences in both rheology and position on the slope. Individual slump sheets show gradations between undulating laminae, inclined and recumbent folds, highly deformed folds, and chaotic textures upslope from the toe region. Debrites are commonly interbedded with slump deposits, whereas imbricated beds are present in the middle and lower parts of the toes of slump sheets near the terminal wall. In the study area, thin‐bedded limestone with slump deposits of the Kelimoli Formation are overlain by fine‐grained, siliciclastic‐dominated, slope deposits of the Wulalike Formation. A thick breccia of the Wulalike Formation was deposited in a main feeder channel in south‐east Wuhai, but to the west‐north‐west the breccia was deposited in distributary channels possibly represented as a unique lower‐slope pattern of gullies. At the latter locality, the breccia was deposited solely within the channels on a steep west‐north‐west dipping slope under density‐driven flows. The mass‐transport deposits documented herein records passive to foreland basin tectonic transitions, and associated platform foundering and steepening of the slope. A slope facies model was constructed to demonstrate the spatial and temporal variations of mass‐transport deposits during basin evolution, and as such it provides a template for the interpretation of the deposits of ancient slopes that underwent passive to active tectonic transitions.

Prediction of Flow around a Vertical Circular Pier in a Discordant Bed Channel Confluence

Prediction of Flow around a Vertical Circular Pier in a Discordant Bed Channel Confluence

Tidally-influenced fluvial channel systems from the Miocene Malay Basin, Malaysia: Evidence from core facies and seismic geomorphological analyses

The interpretation of tidal influence in a depositional system or stratigraphic interval buried deep in the subsurface is mainly based on sedimentary structures, fossils and trace fossils preserved in conventional cores. Studies of modern tidal depositional settings have shown that certain geomorphological features can be used as reliable tidal indicators. In this study we present evidence of tidal influence associated with Miocene channels in the Malay Basin, based on an integrated analysis of sedimentary facies from cores, well logs and high-quality 3D seismic data. Six facies associations identified in cores were interpreted as inter-distributary bay/offshore, tidal flat, subaqueous delta platform/prodelta, tide-influenced channel/bar, mouth bar, and mangrove/overbank deposits. Evidence for tidal influence include rhythmites, thick heterolithic successions, mud drapes, abundant bidirectional current indicators and the presence of an impoverished marine trace fossil assemblage. Channels identified in 3D seismic show unique geomorphological features indicative of tidal influence in the depositional system, such as flaring channel mouths, cuspate meanders, high-sinuosity, as well as dendritic and parallel channel networks comprising several orders of dead-end and through-flowing tributary channels. Identification of tidal geomorphological features in 3D seismic may help in predicting channel fill lithology in the subsurface, and in better planning of hydrocarbon exploration and development in basins with paralic channel-bearing reservoirs.

Groundwater-sourced irrigation and agro-power subsidies: Boon or bane for small/marginal farmers in India?

Growing inequity in access to sustainable irrigation supply services, groundwater and electricity in particular, has become core agendas in many recent global development dialogues on account of food/nutritional security, ensuring on-farm livelihood opportunities, rural poverty alleviation and development. Herein, we aim to present a nation-wide appraisal of eco-environmental and socioeconomic ramifications of subsidizing farm-power services in India, to highlight future requirements to conserve groundwater reserves so as to ensure sustainable irrigation supply services. We adopted a mixed method approach, coupling secondary data analysis (obtained from various governmental archives), with a systematic review of relevant global literature. For the latter, we adopted a multi-stage PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) to summarize observations from post-2000 literature. Our results indicate that, over the years, groundwater has emerged as the mainstay of the irrigation sector in India (via millions of tube/bore wells), replacing surface-water systems (canals). However, unsustainable groundwater drafting has led to (i) significant groundwater drawdowns in most Indian states; (ii) exacerbated greenhouse gas emissions; and (iii) caused extensive soil-water salinization, which impede sustainable agrarian/rural development on long-run. Current literature, however, suggests that, unsustainable groundwater drafting is indulged at policy level only by (i) relaxed groundwater tariffing scheme, and (ii) lucrative agro-power subsidies – collectively which offer the farmers free reign to draft groundwater at will. We reflect on the rise of groundwater market, leading to disproportionate access to groundwater for irrigation, and tragedy of the less-endowed sections of the famring communities. We urge the concerned authorities to devise and implement strategic institutional reforms to bolster the agro-power subsidy delivery mechanisms, and reflect on opportunities of nationwide adoption of feeder channel segregation (FCS) and initiate minimum energy support (MES) schemes. The idea is to make the agro-energy sector more efficient (based on notions of equity, fairness and transparency for all to access the benefits. In the final section we urge the authorities to adopt a systems' thinking approach to identify the key barriers to on-ground implementation of FCS and MES; introduce smart metering system, and above all, incorporate the water-food-energy nexus application in mainstream decision making for irrigation services. The idea is to identify/develop means of resource co-management, identify synergies and trade-off, within a unified framework of irrigation systems’ governance that balances resources supply and demand, without endangering the ecosystem services. We also outline potential research directions; emphasize on need of targeted, process-level investigations with increased case studies, and urge the authorities for improved data dissemination and accessibility.

Coseismic Debris Remains in the Orogen Despite a Decade of Enhanced Landsliding

AbstractMajor earthquakes in steep orogens can trigger extensive landsliding. Most of the landslide bodies come to rest high on the slopes, but subsequent rainfalls can easily remobilize them. Sharp peaks in landslide rates are systematically observed after major earthquakes, followed by rapid decays to background levels in just several years. Yet, the migration of coseismic debris into tributary channels and rivers remains poorly understood. We collected 12 years of observations of the 2008 Wenchuan earthquake's epicentral region in China and evaluated that debris flows and fluvial transport could only evacuate a small portion of coseismic debris, while over 70% of it had stabilized on the hillslopes. Coseismic debris may remain in the orogen for a long time, but estimates based on initial landslide abundance and sediment export are hampered by uncertainties in the debris fate throughout the earthquake cycle.

3-D numerical simulation of curved open channel confluence flow with partially non-submerged rigid vegetation

3-D numerical simulation of curved open channel confluence flow with partially non-submerged rigid vegetation