Channel Slope Research Articles

Integrated hydrological modelling of two contrasting watersheds with a terminal reservoir in the Upper Tapi River basin, India

Abstract The present study developed an integrated hydrologic model for sustainable utilisation and water management in two complex watersheds with varying physioclimatic features and reservoirs. The soil and water assessment tool (SWAT) is used for predicting integrated inflows into the Hatnur reservoir from the Burhanpur and Purna watersheds of the Upper Tapi River basin, while outflows are simulated using a rule curve. The influence of watershed complexities on hydrological model parameters and the watershed processes are investigated using extensive multisite and multivariable calibration (1998–2007) and validation (2008–2013) approaches, including sensitivity and uncertainty analyses. The sensitive parameters are related to curve number (CN), groundwater, slope, and main channel characteristics. The annual streamflow (m3/km2/mm of rainfall) in the Burhanpur watershed is 568.7, which is 4.2 times higher than the Purna watershed's streamflow of 136.2. The hypsometric analysis, areal rainfall, and flow duration curves revealed a substantially different streamflow pattern and a larger coefficient of variation in the spatial distribution of water balance components over sub-watersheds in the Burhanpur watershed compared to the Purna watershed due to diverse topographic features. The developed model would be useful for planning controlled releases from the terminal reservoir to mitigate hazards in the downstream reaches of the Tapi River basin.

Structural equation model of the spatial distribution of water engineering facilities along the Beijing-Hangzhou grand canal and its relationship with natural factors

Water engineering facilities are a crucial component of the Beijing-Hangzhou Grand Canal during the Ming and Qing dynasties, and their distribution is closely related to the hydrological and topographical characteristics of the area. In this study, we reconstructed the canal network distribution map and water engineering facilities database of the Ming and Qing periods using ArcGIS (Geographical information systems software) 10.8 software. We employed Amos (Analyze of Moment Structures) 26.0 software to investigate the influence of various natural environmental factors on the selection of water engineering facility sites. The results revealed a significant correlation between the spatial distribution of water engineering facilities and the main channel slope and slope direction, which had a direct impact. The estimated coefficient for the main channel slope was -0.166, showing a negative correlation with the spatial distribution of water engineering facilities, while the estimated coefficient for the main channel slope direction was − 0.112, also indicating a negative correlation. Moreover, the estimated coefficient for the watershed area where water engineering facilities were located was -0.096, demonstrating a negative correlation. In contrast, the effects of tributary slope and slope direction on the spatial distribution of water engineering facilities were indirect, mediated by the watershed area where these facilities were situated. The effect size for tributary slope was -0.017, showing a negative correlation, while the effect size for tributary slope direction was 0.010, indicating a positive correlation with the spatial distribution of water engineering facilities.The study achieves the integration of the heritage of water engineering facilities along the canal from point to line, provides data support for the construction of the cultural heritage corridor of the canal, and facilitates the promotion of heritage protection and rational layout, which is of great significance to the understanding of the canal culture.

Experimental investigation of the hydraulic performance of porous bottom intakes

Due to the technical problems of bottom intake racks, porous intakes made of rock, gravel, or sand can be a suitable alternative. This research used an experimental model to investigate the performance of porous bottom intake (PBI). To this end, the effects of various parameters, including the main channel slope, grain size distribution of porous media, the geometry of the intake structure, and the water depth in the main channel, have been investigated on the diverted flow rate during sediment-free flow. The performance of one and three-sided designs has also been compared under the same conditions. A comparison of different slopes of the main channel showed that the discharge coefficient and diverted flow of the slope of 1 % are 25 % and 15 % greater than the slope of 1.68 %, respectively. The proportion of the flow that goes through the intakes compared to the overall flow of the main channel varied between 3.5 % and 8 %. Comparing the one- and three-sided PBI models shows that, on average, the flow rate inside three-sided PBI is 72 % higher than one-sided PBI. Finally, a formula has been proposed to calculate the discharge coefficient of PBI using nonlinear multivariate regression, experimental data, and dimensional analysis. The absolute error of this formula for training and testing data is less than 0.1 for more than 95 % of the data.

Steady-state forms of channel profiles shaped by debris flow and fluvial processes

Abstract. Debris flows regularly traverse bedrock channels that dissect steep landscapes, but our understanding of bedrock erosion by debris flows and their impact on steepland morphology is still rudimentary. Quantitative models of steep bedrock channel networks are based on geomorphic transport laws designed to represent erosion by water-dominated flows. To quantify the impact of debris flow erosion on steep channel network form, it is first necessary to develop methods to estimate spatial variations in bulk debris flow properties (e.g., flow depth, velocity) throughout the channel network that can be integrated into landscape evolution models. Here, we propose and evaluate two methods to estimate spatial variations in bulk debris flow properties along the length of a channel profile. We incorporate both methods into a model designed to simulate the evolution of longitudinal channel profiles that evolve in response to debris flow and fluvial processes. To explore this model framework, we propose a general family of debris flow erosion laws where erosion rate is a function of debris flow depth and channel slope. Model results indicate that erosion by debris flows can explain the occurrence of a scaling break in the slope–area curve at low-drainage areas and that upper-network channel morphology may be useful for inferring catchment-averaged erosion rates in quasi-steady landscapes. Validating specific forms of a debris flow incision law, however, would require more detailed model–data comparisons in specific landscapes where input parameters and channel morphometry can be better constrained. Results improve our ability to interpret topographic signals within steep channel networks and identify observational targets critical for constraining a debris flow incision law.

Study on the Stress Evolution and Strengthening Support Timing of the Retracement Channel under the Super-Thick Nappe

The superposition effect of the advanced support pressure of the working face in the final mining stage and the lateral support stress of the roadway is a key factor affecting the stability of the retracement channel. To study the stress evolution of the retracement channel under the super-thick nappe and the timing of strengthening support, this paper takes the mining of the 360808 working face in Xinji No. 1 Mine as the engineering background, analyzes the occurrence conditions of the working face and the measured rock pressure law, and constructs a roof structure model of the retreat area. The UDEC discrete element numerical simulation software was used to analyze the evolution characteristics of concentrated stress and the failure law of surrounding rock around the retracement channel under gradual excavation conditions. Based on the relationship between the position of the main roof fracture and the stability of the surrounding rock of the retracement channel, the instability mechanism of the surrounding rock of the retracement channel was revealed. A mechanical model of the surrounding rock of the retracement channel under the condition of a gradient coal pillar was established, and the energy criterion K for the instability of the surrounding rock was obtained. The method of adding anchor cables to strengthen the support of the surrounding rock of the retracement channel was proposed. The results indicate that the accumulation of energy in the surrounding rock of the retracement channel is greater than the internal consumption of energy, which is the direct reason for the instability of the surrounding rock of the retracement channel. The time to strengthen the support of the roof is when the working face is 15 m away from the retracement channel. According to the analysis of on-site monitoring results, the roof convergence and the two-sides convergence before and after strengthening the support were reduced by 90 mm and 140 mm, respectively. Under the strengthening of support, the slope of the retracement channel in the 360808 working face is slight, without roof fall, and the surrounding rock of the channel is effectively controlled, which is of great significance for ensuring the safe application of the retracement channel. It has reference value for the safety production of surrounding mines and is conducive to promoting the sustainable development of local resource-based society and economy.

Water level prediction using long short-term memory neural network model for a lowland river: a case study on the Tisza River, Central Europe

BackgroundPrecisely predicting the water levels of rivers is critical for planning and supporting flood hazard and risk assessments and maintaining navigation, irrigation, and water withdrawal for urban areas and industry. In Hungary, the water level of rivers has been recorded since the early nineteenth century, and various water level prediction methods were developed. The Discrete Linear Cascade Model (DLCM) has been used since 1980s. However, its performance is not always reliable under the current climate-driven hydrological changes. Therefore, we aimed to test machine learning algorithms to make 7-day ahead forecasts, choose the best-performing model, and compare it with the actual DLCM.ResultsAccording to the results, the Long Short-Term Memory (LSTM) model provided the best results in all time horizons, giving more precise predictions than the Baseline model, the Linear or Multilayer Perceptron Model. Despite underestimating water levels, the validation of the LSTM model revealed that 68.5‒76.1% of predictions fall within the required precision intervals. Predictions were relatively accurate for low (≤ 239 cm) and flood stages (≥ 650 cm), but became less reliable for medium stages (240–649 cm).ConclusionsThe LSTM model provided better results in all hydrological situations than the DLCM. Though, LSTM is not a novel concept, its encoder–decoder architecture is the best option for solving multi-horizon forecasting problems (or “Many-to-Many” problems), and it can be trained effectively on vast volumes of data. Thus, we recommend testing the LSTM model in similar hydrological conditions (e.g., lowland, medium-sized river with low slope and mobile channel) to get reliable water level forecasts under the rapidly changing climate and various human impacts.Graphical

Drainage area is not enough: multivariate hydraulic geometry in the Southern Blue Ridge Mountains, U.S.A.

ABSTRACT Regional hydraulic geometry curves, which relate drainage area to channel morphology, are powerful tools for river restoration and watershed management. While there is a strong correlation between channel morphology and drainage area, the importance of watershed slope and relief on channel-forming flow, especially in mountainous regions, cannot be ignored. This research used single variable power functions along with multiple regression to determine which network- and or local-scale variables are influencing channel morphology in the Southern Blue Ridge Mountains. Within this region, watershed topography (i.e. relief and slope) and or local-scale characteristics (e.g. channel slope and sinuosity) are better predictors of channel morphology than drainage area. Additionally, the importance of local-scale characteristics in the multiple regression models provide strong evidence that site-specific conditions can be just as important as watershed characteristics in determining channel morphology. While multiple regression has been used to create hydraulic geometry equations in other regions, this is the first study that determined whether non-drainage area multiple regression models perform better than models that include drainage area. With the increasing ease with which network- and local-scale characteristics can be calculated, this research shows a clear need to incorporate additional network- and or site-specific characteristics into hydraulic geometry equations.

Steady‐State Bedrock Channel Width

AbstractThe increase in bedrock channel width and the decline in bedrock channel slope with increasing drainage area are fundamental characteristics of mountainous landscapes. Compared with slope, little is known about controls on steady‐state bedrock channel width. We model steady‐state bedrock channel width by iteratively solving models for bed and bank erosion by impacting bedload, using measurable physical parameters, including uplift rate, water discharge, sediment supply, grain size, rock strength, and bank angle. The results indicate that width is largely controlled by sediment flux, rather than water discharge. The commonly used width‐discharge scaling relation is an artifact of the covariance of sediment flux and water discharge. Scaling up from cross‐section to drainage basin scales, our model reproduces the width‐drainage area scaling relation and suggests that the scaling exponent is largely controlled by the downstream change in the fraction of total sediment supply transported as bedload.

Seismic stratigraphy of Late Pleistocene incised valleys and adjacent environments, eastern Central Luconia Province, offshore north‐west Borneo

AbstractIncised valleys are commonly investigated based on outcrop, modern setting and seismic data, which are often limited by data availability, especially for broad (ca >100 km wide) shelf settings. Consequently, few have described complete depositional systems of the incised valleys, especially those linked to their corresponding modern rivers in a source‐to‐sink framework to determine comprehensive controlling factors. This study documents Late Quaternary incised valleys and their characteristics in the Balingian – Central Luconia shelf based on regionally‐extensive three‐dimensional seismic data, two‐dimensional high‐resolution seismic data and boreholes. The three‐dimensional seismic data show that the main Tatau incised valley and tributary Suai incised valley fed the Tatau–Suai shelf‐edge delta. The Tatau incised valley is interpreted as the main incised valley based on its broader width, thicker infill, two‐tier stratigraphic architecture and its larger drainage basin area compared to the tributary Suai incised valley. The Tatau incised valley shifted its direction towards an active tectonic lineament (West Baram Line) and bypassed sediments to the deep‐water via a series of upper slope channels. The Tatau incised valley system comprises the following elements: (i) an upstream segment characterized by rivers dissecting an uplifted hinterland comprising Neogene sedimentary rocks, humid‐tropical vegetation, monsoonal climate, extremely high river discharge and sediment supply; (ii) a midstream segment comprising an emergent, vegetated (tropical rainforest to mangroves) and relatively narrow (ca 150 to 200 km wide) shelf, which was characterized by basinward‐increasing, tectonically‐driven accommodation space, valley incision and deposition; (iii) a downstream segment with increasing tidal‐influence where the Tatau and its tributary valley merged; and (iv) a short (15 to 20 km), narrow (10 to 15 km), tectonically‐controlled shelf‐edge delta and channelized upper slope. This study demonstrates the value of documenting an incised valley system in the context of its broader source‐to‐sink setting, which may provide a useful analogue for ancient incised valleys in comparable geological settings.

Numerical study on upstream smoke propagation and induced airflow velocity in a tilted channel under natural ventilation

A series of fire simulations were executed to explore the upstream smoke propagation characteristics and induced airflow velocity in tilted channels under natural ventilation. The channel slope ranging from horizontal to 58% (30°) and five heat release rates were used. Simulative results indicate that the airflow introduced by stack effect can enable the upstream smoke spread to reach sub-critical, critical and super-critical states without forced longitudinal ventilation. Meanwhile, taking the effect of fire heat release rate and height difference between the fire source and the upper portal into account, a piecewise function is developed to estimate the induced airflow velocity. It is found that when Ld∗·Q∗0.2 is less than or equal to 1.05, the airflow velocity increases exponentially with the variety of dimensionless elevation difference, but slowly rises logarithmically when Ld∗·Q∗0.2 is greater than 1.05. Besides, for scenarios in the sub-critical state, the relationship between the induced airflow velocity and the upstream smoke backflow length is revealed, which demonstrates that the dimensionless reverse flow length is in inverse proportion to the 1.5 power of dimensionless airflow velocity. For scenarios in the critical and super-critical states, there is still smoke backflow upstream of the fire source at the early period of a fire. And the disappearing time of smoke backflow reduces exponentially with the increase of heat release rate and elevation difference. Based on dimensional analysis and simulative data, a novel predictive model for the backflow disappearing time is proposed.

Improvement of the photovoltaic panel cooling by natural air ventilation

AbstractThe operating temperature increase in solar photovoltaic modules is a major problem, which affects their performance negatively. This numerical study introduces the effect of natural convection air‐cooling on the performance a novel hybrid photovoltaic/thermal collector. The standard k‐ε turbulence model is implemented for describing the turbulent natural convection. For improving the heat transfer rate of a novel photovoltaic/thermal collector system (PV/T), a sloped entrance channel (SEC) and an aluminum flat plate (AFP) were installed. The effects of SEC geometry parameters, the number of AFP and their distance to the photovoltaic module (PV) on the average Nusselt number are investigated. In addition, the effect of the PV/T system tilt angle and Rayleigh number on the thermo‐hydrodynamic flow behavior has been discussed. The results indicated that the heat transfer rate of the new hybrid PV/T system was improved by up to 20%, compared to the reference case without an aluminum flat plate. In addition, increasing the tilt angle of the PV/T system boosts airflow velocity, particularly for high Rayleigh number values (with and without AFP). Furthermore, several correlations, as functions of Rayleigh numbers and inlet channel dimensions, have been developed to predict the average Nusselt number.

Building a bimodal landscape: bedrock lithology and bed thickness controls on the morphology of Last Chance Canyon, New Mexico, USA

Abstract. We explore how rock properties and channel morphology vary with rock type in Last Chance Canyon, Guadalupe Mountains, New Mexico, USA. The rocks here are composed of horizontally to near-horizontally interbedded carbonate and sandstone. This study focuses on first- and second-order channel sections, where the streams have a lower channel steepness index (ksn) upstream and transition to higher ksn values downstream. We hypothesize that differences in bed thickness and rock strength influence ksn values, both locally by influencing bulk bedrock strength and also nonlocally through the production of coarse sediment. We collected discontinuity intensity data (the length of bedding planes and fractures per unit area), Schmidt hammer rebound measurements, and measured the largest boulder at every 12.2 m elevation contour to test this hypothesis. Bedrock and boulder mineralogy were determined using a lab-based carbonate dissolution method. High-resolution orthomosaics and digital surface models (DSMs) were generated from drone and ground-based photogrammetry. The orthomosaics were used to map channel sections with exposed bedrock. The United States Geological Survey (USGS) 10 m digital elevation models (DEMs) were used to measure channel slope and hillslope relief. We find that discontinuity intensity is negatively correlated with Schmidt hammer rebound values in sandstone bedrock. Channel steepness tends to be higher where reaches are primarily incising through more thickly bedded carbonate bedrock and lower where more thinly bedded sandstone is exposed. Bedrock properties also influence channel morphology indirectly, through coarse sediment input from adjacent hillslopes. Thickly bedded rock layers on hillslopes erode to contribute larger colluvial sediment to adjacent channels, and these reaches have higher ksn values. Larger and more competent carbonate sediment armors both the carbonate and the more erodible sandstone and reduces steepness contrasts across rock types. We interpret that in the relatively steep, high-level ksn downstream channel sections, the slope is primarily controlled by the coarse alluvial cover. We further posit that the upstream low-level ksn reaches have a base level that is fixed by the steep downstream reaches, resulting in a stable configuration, where channel slopes have adjusted to lithologic differences and/or sediment armor.

Effect of Surface Roughness and Channel Slope on Hydraulic Jump Characteristics: An Experimental Approach Towards Sustainable Environment

Effect of Surface Roughness and Channel Slope on Hydraulic Jump Characteristics: An Experimental Approach Towards Sustainable Environment

ON METHODS FOR DETERMINING THE ROUGHNESS COEFFICIENT OF CHANNELS ALONG THE PERIMETER

The scientific article deals with the issues of uniform movement of the riverbed and the determination of the roughness coefficient of the riverbed (roughness coefficient). The analysis of existing methods for calculating the difference in the roughness coefficients of channels along the perimeter, methods for determining the roughness coefficient of the slopes of channels consisting of two or three parts along the perimeter, well–known scientists - P.N.Belokon, G.K.Lotter, N.N.Pavlovsky are given.There are a some varieties of calculation methods assigned for hydraulic calculations of water flow along the perimeter of a soil channel in the field of hydraulic engineering. A number of researchers states that the roughness of the channel bed imitates the motion of the flow in diverse channels with the movement of the flow under the ice layer. Nevertheless, it should be taken into account that the roughness of the channel bed has its own characteristic (specific) features of the movement of water in different open channels and below the ice cover. The common formulas proposed by number of authors for channels with different roughness along the perimeter cannot be used directly in hydraulic calculations of the flow under the ice cover, and vice versa, the equations of motion of water flow beneath the ice cover are not applied even for channels with various roughness along the perimeter. Therefore, the corresponding choice of methods for determining the roughness coefficients of the canal flow along the perimeter will be the key point to its long-term functioning.

Implicit Algorithm for Threshold Stream Power Incision Model

AbstractWe present an O(n) complexity and implicit algorithm for the two‐dimensional solution of the stream power incision model (SPIM) enriched by a discharge threshold term and taking into account variability in rainfall and thus discharge. The algorithm is based on the formulation developed by Deal et al. (2018, https://doi.org/10.1002/2017jf004393) and the generalization of the FastScape algorithm (Braun & Willett, 2013, https://doi.org/10.1016/j.geomorph.2012.10.008) where the slope is approximated by first‐order accurate finite difference. We consider a variety of discharge thresholds that vary in their dependence on channel slope. The algorithm requires finding the root of a non‐linear equation using a Newton‐Raphson iterative scheme. We show that the convergence of this scheme is unconditional, except for a narrow range of model parameters where the threshold increases with the slope and for low discharge variability. We also show that the rate of convergence of the iterative scheme is directly proportional to the slope exponent n in the SPIM. We compare the algorithm to analytical solutions and to numerical solutions obtained using a higher‐order finite difference scheme. We show that the accuracy of the FastScape algorithm and its generalization presented here is comparable to other schemes for values of n > 1. We also confirm that the FastScape algorithm and its generalization to variable discharge + threshold conditions does not need to satisfy the CFL condition and provides an accurate solution for both small and very long time steps. We finally use the new algorithm to quantify how the existence of an erosional threshold strongly affects the length of the post‐orogenic decay of mountain belts.

A Model for Mid‐Holocene—Present U.S. Mid‐Atlantic Piedmont River Corridor Sediment Budgets Fit to Stratigraphic Data

AbstractFluvial sediment transport and deposition shapes river, floodplain, and estuarine systems but also can create water quality problems, which in some cases motivates efforts to reduce hillslope erosion. However, watershed management efforts rarely consider the fate of eroded sediments and the time scale of transport to estuaries. This study presents a modeling approach to estimate regionally averaged floodplain deposition, erosion, and sediment flux for the mid‐Atlantic U.S. caused by changing forest cover, urban development, and milldam construction. Regional regression equations estimate discharge at 3‐month intervals, and (temporally invariant) channel width and slope. Sediment concentrations are determined from a rating curve (defined for modern conditions by gaging‐station data). Tuning the model to floodplain stratigraphic data suggests that‐sediment concentrations prior to European colonization (i.e., before ∼1750) were 5%–8% of those prevailing today, while legacy (1750–1950) sediment concentrations were 25%–35% of present values. The calibration process, however, is only partly successful for the period before 1750 due to the limited number of older dated samples available. Nonetheless, the model accurately reproduces the observed age distribution of floodplain deposits. Computed sediment‐budget components increase monotonically from before 1750 to the present, and the ratio of budget components remains similar from one time period to the next. The model also predicts that millennial timescales are needed for mid‐Atlantic floodplains to equilibrate following a change in sediment regime, a finding with important implications for river corridor and watershed restoration planning.

Channel Profiles Reveal Fault Activity along the Longmen Shan, Eastern Tibetan Plateau

Assessing fault activity in regions lacking Quaternary sedimentary constraints remains a global challenge. In this study, we used channel slope distribution to examine variations in rock uplift along faults. By comparing channel steepness with published low-temperature thermochronology and paleo-seismic data, we identified deformation changes both perpendicular to and along the Longmen Shan at various time scales. Our data revealed distinct fault segments displaying distinct thrust activities along the Longmen Shan’s strike. In the southern segment, the Dachuan fault exhibited the highest activity, and its movement had persisted for millions of years. In the central segment, the Wenchuan fault was active during theearly Quaternary but has become dormant since the late Pleistocene. Within the past millions of years, the Yingxiu and Pengguan faults displayed significant vertical displacement. Fault activity in the northern Longmen Shan was relatively weak, with the Qingchuan fault transitioning from thrust movement during the Neogene to pure strike-slip activity since the Pleistocene. Overall, the Dachuan and Huya faults exhibited deformation patterns similar to the Yingxiu fault during the Quaternary. Similar to the Yingxiu fault, which triggered the Wenchuan earthquake, the Dachuan and Huya faults possess the capacity to produce significant earthquakes in the future. The variations in deformation perpendicular to and along the Longmen Shan fault system underscore the importance of upper crustal shortening in shaping the rock uplift patterns and topography of the eastern Tibetan Plateau margin.

FEATURES OF RELIEF OF THE BORZHAVA RIVER MIDDLE FLOW AREA AND THEIR CONNECTION WITH GEODYNAMICS AND SEISMOTECTONICS

With attraction of the newest (until 2010–2022 inclusive) geological-geophysical and geodetic data and geological-tectonic construction, the features of relief of the Borzhava River middle flow area (Ukrainian Transcarpathians) were analyzed, including peculiarities of the morphology of the river valley, their connection with the geodynamics and seismotectonics of the territory is traced. In the interval between Keretsky and Dovge villages the river flows in the valley of south – southeast direction between the southwestern slopes of the Folded Carpathians and northeastern slopes of Vygorlat-Guta volcanic ridge, tracing the near-surface localization of Transcarpathian deep fault zone geological structures (fault-suture, i.e. contact zones of the tectonic structures of the Transcarpathian depression and the Folded Carpathians). In the Dovge village river terns to the southwest and crosses the Vygorlat-Guta ridge in this direction in the interval to the Velyki Komyaty village, its valley here is associated with rupture discontinuities of the diagonal Borzhava fault zone. The place of terns of the Borzhava River in the Dovge village is connected with the area of junction of the structures of the Borzhava fault zone and the Transcarpathian fault-suture zone. The Onok height and the Velykyy Sholles volcanic ridge, which surround it from the southeast and east, are connected with influence of the diagonal Vynohradiv and meridional Oash faults. In the northeastern parth of studied area, under the mountain ranges of the Kuk – Palenyy Grun` ridges, a relatively deep (40–55 km) zone of seismic activity was discovered, it is related to the area of junction of the deep tectonic structures of the Transcarpathian and Oash fault zones, the first of which dips in the northeast direction under the Carpathians, and the second (its tilted subfault) dips in the eastern direction under the structures of the Solotvyno depression. Also regular, including the newest (2 perceptible earthquakes since the beginning of 2023) seismic activity (mainly at the depths of the pre-Neogene basement (2–6 km)) is demonstrated in the studied area (along with fault-block structures of the Transcarpathian trough and fold-thrust structures of the Folded Carpathians) by the structures Borzhava fault zone (orthogonal to the Carpathians, mini-graben in structure) and conjugated with it, the more submeridional Shalanky-Irshava (slightly sigmoid in plan) and Petrovo-Ardanovo faults. The genesis of the specified peculiarities of the relief and seismicity of the studied area is analyzed from the point of view of a combination of "alpine" (thrust-subduction of the crustal structures of the Transcarpathian depression and sedimentary strata of the modern Folded Carpathians to the northeast – the so-called multi-tiered "crocodile" tectonics), present "terrain" (shift to the east of the crustal structures of the Transcarpathian depression – northeastern end of the Alkapa terrane – superimposed, relatively low-amplitude process) and "asthenolitic" ("spreading" of convective flows from the asthenolite under Pannonia) components of late Neogene ("post-magmatic", up to 5–7 million years ago) and modern regional geodynamic process. Key words: Ukrainian Transcarpathians; Borzhava River valley; cross section; channel slope; faults; geodynamics; earthquake; seismotectonics.

Lane formation of colloidal particles driven in parallel by gravity.

We investigate the lane formation in nonequilibrium systems of colloidal particles moving in parallel that are driven by the force of gravity. For this setup, an experimental implementation of a channel on a slope can be conceptualized. We employ the Brownian dynamics algorithm and confine the repulsive particles with hard walls based on the solution of the Smoluchowski equationin the half space. A difference of the driving force acting on the colloids could be achieved by using two spherical particle types with differing diameters but equal mass density. First, we investigate how a difference in the channel slope affects the lane formation of the systems, after which we analyze the lanes that formed. We find that the large particles push the small particles to the walls, resulting in exclusively small particle lanes at the walls. This contrasts the equilibrium state, where depletion forces push the larger particles to the walls. Additionally, we have a closer look at the mechanisms by which the lanes form. Finally, we find system parameter values that foster lane formation to lay the foundation for an experimental realization of our proposed setup. To round this off, we give an exemplary calculation of the slope angle needed to get the experimental system into a state of lane order. With the examination of lane order in systems that are driven in parallel, we hope to deepen our understanding of nonequilibrium order phenomena.

The heterogeneous geomorphological impact of an exceptional flood event and the role of floodplain vegetation

AbstractApplication of an integrated spatial approach combining several sources of remote sensing data to include both channel and floodplain morphological and sedimentological impacts has identified the geomorphological effects of three extreme flood events during a single flood season (2019–2020) along a 16‐km reach of the River Teme, UK. This combined approach allowed the assessment of in‐channel pattern development, incision and aggradation; lateral bank migration; and overbank sedimentation and scour by out‐of‐channel flows. Rates of change during the event period were compared with those in the previous 10 years. The approach also allowed the role of vegetation and cultivation, both bankside and out on floodplains, to be assessed with variations in the extent of riparian wood and channel slope driving contrasts in the extent of the response. The spatial impacts from such extreme events are highly localised, varied in kind, and can be considered for both rivers and floodplains together. Erosional effects were distinctively distributed and not simply contributions to ongoing meander development; channel aggradation was localised, and overbank sedimentation explicably patchy. In reaches without woody vegetation, differences in channel and floodplain slope, local floodplain relief as created by prior events, and the impact of man‐made structures were factors that drove variations in flood response. This study strongly underlines the role of continuous riparian vegetation in maintaining bank stability and constraining lateral channel migration, but also to the potential influence of floodplain vegetation and planting for ‘natural engineering’ in the context of floodplains as well as channels in comparable environments. Maintenance of riparian vegetation in the context of landowner and Natural England conflict and management of future flood risk is important, but also highlighted is the need to consider the role of hedgerows and wider planting for constraining soil and riverbank erosion during flood events.