Channel Slope Research Articles

Experimental Evaluation of Hydraulic Jump Characteristics in Gradually Expanding Sloping Channel

Understanding hydraulic jumps in gradually expanding sloping channels is crucial for designing eco-friendly water management systems that minimize environmental impacts. This study seeks to investigate how the expansion ratio and channel slope together influence the characteristics of hydraulic jumps. The experiments were performed on four different channel slopes (00, 20, 40, and 60) and four distinct expansion ratios (B = b1/b2) of 0.35, 0.45, 0.55 and 0.75. The Reynolds number was ranged from 7150 to 27750, while the Froude number varied between 2.5 and 8.5 during the experiments. Novel correlations were developed to predict key hydraulic jump parameters, including depth ratio (d₂/d₁), relative energy loss (EL/E₁) and relative jump length (Lj/d₁), by considering the effects of expansion ratio, channel slope and Froude number. The results indicate that as the channel slope increased from 0° to 6°, the depth ratio and relative energy loss increased by approximately30.53% and 15.37%, respectively, while the relative jump length decreased by 11.11%. Conversely, as the expansion ratio decreased from 1.0 to 0.35, the depth ratio and relative jump length were reduced by approximately 9.63% and 10.42%, respectively; while the relative energy loss was increased by 24.21%.These findings highlight the significant influence of channel geometry on hydraulic jump characteristics, offering valuable insights for optimizing water conveyance structures. The proposed correlations provide a novel and intuitive approach to analyze hydraulic jumps in expanding sloping channels, addressing gaps in existing literature and contributing to sustainable water resource management.

Pemetaan Topografi Saluran Drainase Ruas Jalan Pangeran Diponegoro – Yos Sudarso Kota Samarinda Provinsi Kalimantan Timur

This research is motivated by the frequent occurrence of waterlogging or flooding at the research location due to insufficient drainage capacity to accommodate the large volume of water. Therefore, topographic mapping of the drainage channels is conducted, with the data intended for planning the installation of pumps and normalization of the drainage channels. This study aims to describe the situational topography and present longitudinal and cross-sectional profile maps, as well as drainage volume information using AutoCAD Civil 3D 2022 and ArcMap 10.8. The topographic mapping of the drainage channels resulted in topographic maps, longitudinal profile (Long Section) maps, and cross-sectional profile (Cross Section) maps with a total of 202 coordinate points, an overall road length of 664 meters, 28 stations, divided into 25 meters for each station section, and a total drainage volume of 2104.17 cubic meters along Pangeran Diponegoro – Yos Sudarso road. Additionally, the presentation of the drainage channel slope was included. This research was conducted on Jalan Pangeran Diponegoro – Yos Sudarso in Samarinda City. The measurements in this study utilized the ComNav T300 Geodetic GPS using the Real-Time Kinematic (RTK) method.

Analytical and numerical modeling of shallow water flow in a channel: Theoretical approaches and simulations

This study focuses on the modeling and simulation of shallow water flows in a channel through the application of the Saint-Venant equations. Two main approaches were explored: an analytical solution and a numerical method based on finite difference discretization. The analytical solution provides exact expressions for water depth and velocity under simplified conditions, offering a reference point for validating numerical simulations. The numerical method, on the other hand, captures more complex dynamics such as wave propagation and nonlinear interactions between sections of the channel. The simulations reveal an inverse relationship between water depth and flow velocity, confirming the validity of the governing equations. Moreover, the influence of parameters such as channel slope, flow rate, and boundary conditions on the system?s dynamics is clearly illustrated. The comparative analysis of the two approaches shows that the finite difference method is a powerful tool for practical applications in hydraulic engineering, allowing for the accurate modeling of real-world phenomena while offering greater flexibility compared to idealized analytical solutions.

Safety inspection and diagnosis methods for long-distance water conveyance channels coupled with BIM and drones

ABSTRACT With the rapid development of science and technology, unmanned aerial vehicle inspection technology has also been widely applied in various fields of society. To solve the problem of low efficiency in current long-distance water channel inspection and slope damage diagnosis methods, this study proposes a long-distance water channel safety inspection method that combines building information models and drones. It combines a support vector machine, genetic algorithm, and principal component analysis algorithm to construct a slope failure diagnosis (SFD) model based on this algorithm. In the performance comparison, it was found that the average accuracy and average runtime were 98.18% and 0.19 s, which were superior to the compared algorithms. Subsequently, the effectiveness analysis of the detection method showed that it was effective. Finally, in the performance comparison of the SFD model, the F1 values for the four types of slope failures were 98.4, 96.3, 97.8, and 96.9%, all of which performed the best. This indicates that the proposed long-distance water transmission channel inspection and diagnosis methods have good performance and practicality, and can provide a theoretical basis for water transmission channel inspection and disaster diagnosis.

Quantitative geomorphological analyses reveal late Cenozoic uneven tectonic expansion at the North Qilian Shan

Abstract The North Qilian Shan, located in the northeastern Tibetan Plateau, serves as a tectonic boundary zone both for active blocks and plateau expansion, and is characterized geomorphologically by intense shortening and uplift. To quantify the geomorphic expression of the outward expansion, we selected the Dongda River Watershed as the study area, divided it into three tectonic regions (A, B and C) to conduct quantitative geomorphological analyses. We then calculated the geomorphic indices—normalized channel steepness (ksn), slope, relief and hypsometric integral (HI)—for 212 sub‐basins in the Dongda River Watershed using TopoToolbox and the Topographic Analysis Kit (TAK). The distribution of parameters showed that the tectonic activity in the study area is Region A > Region C > Region B, which indicated that the North Qilian Shan exhibits geomorphic evidence of uneven tectonic uplift, reflecting differential tectonic activity along the North Qilian Shan fault zones during the Late Cenozoic. When combined with previously established tectonic evolution models for the North Qilian Shan, the results in this study suggest that tectonic activity here is driven both by the northward expansion of the plateau boundary and by stress transmission within block boundary zones.

Propofol Inhibits Piezo Mechanosensitive Channels.

Propofol Inhibits Piezo Mechanosensitive Channels.

Longitudinal Ceiling Temperature Profile in an Inclined Channel Induced by a Wall-Attached Fire

Channel fire poses a great threat to personnel safety and structural strength, in which the temperature profile is worthy of attention. In this paper, the longitudinal temperature profile of a ceiling jet induced by a wall-attached fire with different channel slopes was experimentally investigated using a 1:8 reduced-scale channel. The results show the following: (1) For channel fire with a horizontal ceiling, the influence of the burner aspect ratio and source-ceiling height on the temperature profile is monotonous in the cases considered in this work. With a larger burner aspect ratio and larger source-ceiling distance, more ambient air could be entrained; hence, the longitudinal temperature under the ceiling decays faster. (2) For channel fire with an inclined ceiling, when the burner aspect ratio and source-ceiling distance remain constant, the asymmetric entrainment induced by the flame under larger channel slope leads to more hot smoke being transported upstream. Consequently, the temperature profile is not symmetric, with higher temperatures upstream and lower temperatures downstream. (3) Combining the influence of the burner aspect ratios, source-ceiling distance, and burner aspect ratio, the characteristic length scale was modified. Based on this, a model describing the ceiling temperature profile was proposed and then verified with previous data.

Establishing a Geological Knowledge Base for Braided River Deltas Using Google Earth

This study quantifies morphological features of global braided river deltas using Google Earth imagery, analyzing eight systems (e.g., Yukon–Kuskokwim, Poyang Lake, Lena River deltas). Methods include listwise deletion for missing data (retaining 87% of Poyang Lake delta samples) and sensitivity analysis (threshold changes ≤2.4%). Nonparametric tests (Kruskal–Wallis, H = 12.73, p = 0.005) show significant differences in bifurcation angles across deltas, with the wave-dominated Po River (59.2°) having an 18% higher 80% threshold the than tide-dominated Poyang Lake (50.1°, p = 0.003). Key quantitative results include the following: 1.65% of bifurcation angles cluster at 30–60°, differing from fan deltas (p < 0.01); wavelength–amplitude relationships are nonlinear (R2 = 0.537–0.913), with positive slopes indicating a high sediment supply (e.g., Yukon–Kuskokwim) and negative slope channel avulsion (e.g., Poyang Lake); bifurcation spacing correlates with the sediment supply—54% of Poyang Lake spacings < 2000 m (dense networks) vs. 80% of Lena River spacings < 15,000 m (stable channels). The resulting dataset enables global, remote-sensing-based comparisons, providing thresholds for sedimentary modeling and reservoir prediction. Moderate missing data (≤13%) minimally affect results, though high-missingness cases need further analysis. This study replaces empirical rules with statistical validation, showing that morphometric differences reflect depositional dynamics, which are critical for reservoir heterogeneity assessments.

Influence of the Slope of the Bottom of the Prismatic Channel on the Length of the HydraulicJump

Abstract. Problem. The occurrence of a hydraulic jump in road drainage systems significantly affects their reliability and can cause their destruction. Determination of measures to eliminate the negative consequences of a jump is an important task in the engineering design of road structures. There are difficulties associated with the imperfect determination of the geometric characteristics of the hydraulic jump, primarily the length of the jump, due to the use of empirical formulas and laboratory and numerical modeling. The appearance of the equation of sharply changing motion in prismatic channels made it possible to investigate the influence of various hydraulic characteristics of the flow, including the slope of the channel, on the shape of the flow surface using analytical methods. The hydraulic approach mentioned in the study of the length of the hydraulic jump needs to be checked based on a numerical simulation of the flow of real liquid and a comparative analysis of the results of hydraulic and numerical simulation. Goal. The purpose of this study is to determine the influence of the slope of the channel on the length of the hydraulic jump that occurs at the outlet section behind the connecting structure. The research aims to demonstrate the possibilities of hydraulic methods in solving problems related to sharply changing flows in open channels and to check the obtained results and conclusions using modern numerical modeling methods. Methodology. The methodological basis of the study is the use of the equation of sharply changing fluid movement in a prismatic channel in a linearized form and obtaining from it the main analytical dependencies that can be used at the stage of designing structures of road drainage systems. Results. Using the example of the analysis of the influence of the slope of the bottom of the exit section of a one-step drop on the length of the hydraulic jump, the effectiveness of using hydraulic methods in determining the characteristics of this dangerous phenomenon is shown. Two extreme cases are considered. Channels with a wide cross-section, which made it possible to neglect the influence of the side walls, and narrow channels with the most hydraulically advantageous cross-section. The corresponding formulas have been obtained. It was concluded that as the channel width decreases compared to its depth, the jump length becomes more sensitive to changes in channel slope. Numerical calculations of perfect and wavy hydraulic jumps over a one-step drop in a channel of rectangular cross-section were carried out on the basis of a real fluid model. As a result, the dependences obtained using the equation of sharply changing fluid movement in a prismatic channel were quantitatively and qualitatively confirmed. Originality. The proposed approach allows, while remaining within the framework of standard mathematical training offered by technical educational institutions, to effectively use hydraulic methods to study sharply changing fluid movements using the example of a hydraulic jump. Practical value. From a practical point of view, the formulas obtained in the work make it possible to qualitatively and quantitatively estimate the size of erosion formations from hydraulic jump and the size of energy quenchers to prevent the destructive consequences of this dangerous phenomenon.

Evaluation and optimal width ratio selection of microbial mineralization technique in the repair of lining cracks in Xinjiang desert open channel

The bank slope structure of the open channel in the Xinjiang desert is affected by seasonal climate changes and water erosion, leading to lining cracking. This study identified the optimal culture conditions and mineralization factors for Sporosarcina pasteurii through strain cultivation and precipitation assays. Subsequently, 0.1~5.0 mm wide penetrating concrete cracks were prefabricated, and microbially induced calcium carbonate precipitation (MICP) repair tests were conducted over 16 cycles. These experiments included macroscopic performance evaluations, such as area repair rate, penetration resistance, and capillary water absorption tests, alongside microscopic analyses using X-ray diffraction and scanning electron microscopy. The results indicate that MICP technology effectively repairs narrow cracks, preserving crack surface integrity, significantly reducing permeability and water absorption, and enhancing the durability of the concrete. However, for cracks exceeding 1.0 mm in width, the repair efficiency declines progressively. Based on the experimental data, it is concluded that a crack width of 1.0 mm is the optimal threshold for effective MICP-based repair within 16 cycles, ensuring both structural integrity and optimal waterproofing. These results offer valuable insights into the potential application of MICP technology for the remediation of lining cracks in the bank slopes of water conveyance channels in Xinjiang Desert.

Energy Loss Characterization in Stepped Spillways: Experimental Study and Model Development for Slopes of 8.9°–26.6°

Stepped spillways are structures built across dams to lessen the kinetic energy that could create scour at the natural riverbed below it. These structures utilize their stepped design to manage the energy in floodwaters. Numerous studies have point out the damaging effects of the kinetic energy from falling water on the riverbed beneath the structure, particularly with channel slopes exceeding 26.6 degrees. However, few studies have examined the energy loss caused by flat stepped spillways with channel slopes between 26.6 and 8.9 degrees. There is a knowledge gap in the design requirements for flat stepped spillways within these specific channel slopes. The present model to predict energy dissipation in flat stepped spillways incorporates a parameter known as the friction factor, f, which is difficult to estimate and often requires subjective assessment by those who design stepped spillways. This research aims to offer design guidelines for flat stepped spillways, which feature varying slopes of 26.6 degrees and 8.9 degrees, and to substitute the problematic friction factor, f. Experiments were done in big facilities employing phase-detection intrusive probes on flat stepped spillways with channel slopes ranging from 26.6 to 8.9 degrees. This paper presents a model for assessing energy losses in flat stepped spillways with slopes of 26.6 and 8.9 degrees under transitional and skimming flow conditions. The outcomes from the new model correlated well with the measured data, displaying high correlation coefficients between 0.79 and 1.00. All the findings were consistent. The model is user-friendly and provides superior results compared to the previous model.

Investigation of sediment particle shape and channel slope on Manning’s coefficient for gravel bed rivers (an experimental study)

ABSTRACT The inability to accurately estimate the Manning roughness coefficient (n) and the use of a constant value of n are major sources of uncertainty in flood simulations and flow-depth calculations. The river flow roughness coefficient is typically not constant and changes dynamically as the flow-depth changes. The main purpose of the present study is to more precisely determine n for different gravel sizes, gravel shapes (rounded and sharp-corner types), and channel slopes. To the best of our knowledge, there is no study to consider these three factors simultaneously. A total of 160 experimental tests are conducted in a rectangular channel furnished with different bed roughness and different bed slopes. Results show that n with sharp-cornered pebbles is higher than n for rounded natural pebbles, and the difference increases with the increase of bed slope, decreases in relative submergence, and decreases in the size of pebble particles. The increase in relative submergence causes a 25.8% decrease in n for broken particles with sharp corners and a 25.2% decrease for particles with round corners. The effect of particle shape on n is significant in steep slopes and relatively low submergence (large-scale roughness).

Identification of sand injectite facies in core: their significance to developing a reservoir model for the Chestnut oilfield, UK Continental Shelf

A reinterpretation of the only core (taken in 1988) through the reservoir sandstone in the Chestnut oilfield changed the interpretation of the reservoir from a base-of-slope turbidite system downdip from a known slope channel to a sand injectite reservoir. Using the base-of-slope turbidite model, four unsuccessful appraisal wells were drilled, and it was concluded that the reservoir was more complex than anticipated, or that the sedimentary model was incorrect. A new examination of the core identified numerous well-preserved characteristics associated with sand injectite reservoirs, including internal structures and hydrofractures. No firm evidence of depositional structures was found. The new interpretation led to changes in the field-wide reservoir model that transformed the Chestnut Field from an uneconomic discovery into a producing oilfield that exceeded expectations. Examples of the injectite facies, including evidence of erosion during sand injection, are provided, together with evidence of hydrofractures along lithological boundaries and in mudstone intervals that allow association between hydrofractures and sand injection.

The Use of a Diagonal Photoflow System Combined with a High‐Power UV LED in High‐Speed C─H Bromination Reactions

Abstract A high‐speed photoflow benzylic C─H bromination using N‐bromosuccinimide (NBS) was achieved by combining a diagonal photoflow reactor (LX‐1, MiChS) with a high‐power UV‐LED (365 nm) system. The LX‐1 reactor contains sloped parallel channels that allows thin‐film fluids to be effectively exposed to intensive light. Compared to other flow processes that have been reported so far for benzylic C─H bromination, this new photoflow setup enables more efficient performance as demonstrated by the significantly shortened residence time (6 to 13 s) in the system. The C‐H bromination of various alkyl arenes proceeded efficiently to give the corresponding C‐H brominated products in good yields. The synthetic utility of this protocol was demonstrated in the successful gram‐scale synthesis of the antiplatelet agent, ticlopidine, by the photoflow benzylic C─H bromination of ortho‐chlorotoluene and the subsequent nucleophilic substitution of a bromide ion by 4,5,6,7‐tetrahydrothieno[3,2‐c]pyridine.

The hydro‐geomorphic effects of wooden leaky barriers in a steep headwater stream

Abstract Purposely placed in‐stream wooden leaky barriers (LBs) with lower gaps to facilitate flow during average conditions have become a popular type of nature‐based intervention in catchments for flood risk mitigation. Empirical evidence on their effectiveness remains rare, however. The hydro‐geomorphic effects of 16 LBs were monitored over three years on the Elm Sike, a small upland stream (catchment area: 0.33 km2) in the Scottish Borders, UK. The aims of the structures were to: (1) increase water storage and roughness and, in turn, attenuate and delay flood peaks; and (2) trap and store coarse sediment to reduce sediment‐related problems downstream. Annual topographical surveys were conducted to assess geomorphic changes, and continuous 5‐minute water levels were recorded to assess changes in peak flow travel times. Two‐dimensional hydraulic modelling (HEC‐RAS 2D) was undertaken to assess the hydraulic impact of the structures and geomorphic changes. The LBs had no effect on peak flow travel time and rate of stage rise or fall based on 22 events with an Annual Exceedance Probability (AEP) of ≥ 3.7%. Hydraulic modelling showed limited velocity reduction and expansion of inundation extent due to the LBs for 50% AEP flows, but slightly greater effects for larger 5% AEP flows. However, for 50% AEP flows, inundation extent increased and velocities decreased more significantly due to morphological changes initiated by the structures. The limited hydrological and hydraulic impacts were related to the small size of the structures, close spacing and the steep, confined valley setting that limited water storage capacity. At the end of the three‐year period, a reach‐wide net deposition response of 3.49 ± 0.36 m3 and a 5.3% loss of total LB backwater storage were observed, but local geomorphic response due to the LBs was spatially variable. Backwater capacity at 10 structures was reduced, and the lower gap increased at eight structures due to bed scour, indicating accelerated underflow. Multivariable analysis showed that gap height change was inversely related to backwater shear stress, channel cross‐section area and channel slope. No factors explained backwater sediment deposition, but a threshold lower gap height of ≤0.4 m for initiating deposition was evident. These hydro‐geomorphic observations have implications for the design and placement of LBs in river restoration and flood risk management projects.

Open Channel Banki Cross-flow Turbine Slope CFD Analysis with Two Different Constant Approaches

Electrical energy has become an inescapable need for people worldwide, including Indonesia. Currently, fossil fuels are still the primary basis for producing electrical energy. Apart from the high emissions produced, fossil fuels are also non-renewable. Renewable energy, such as pico hydropower, is necessary to secure the electricity supply. Pico hydropower is the smallest scale of hydropower that generates electricity smaller than 5kW and usually works in low head conditions. Open channel cross-flow turbines are the right choice for pico hydroelectric power plants because they are suitable for operation at low head conditions. For this reason, it is necessary to analyze parameters that can influence the value of open channel cross-flow turbine efficiency, including the channel slope, channel turning angle, and inlet position angle, which are interdependent. This study examines the influence of the turning and inlet angles on the open channel cross-flow turbine’s efficiency and the significance between those parameters. This analysis was carried out using CFD simulations, where the slope of the channel is a variable that will be varied. Moreover, there are two different approaches while varying the channel slop: the constant inlet angle approach and the constant turning angle approach. The CFD simulation was conducted using the ANSYS Fluent software in the transient multiphase two-dimension domain. This study finds that the optimum canal slope is at 60° with the turning angle kept constant at 90°, producing a maximum efficiency of 81.88%.

Numerical Calculations for the Length of the Transitory Zone in Partially Filled Circular Pipes with Steep Slope

Three-dimensional turbulent free-surface flow through smooth and corrugated circular pipes with steep slope is simulated by means of Computational Fluid Dynamics (CFD). For this purpose, the three-dimensional Reynolds Averaged Navier-Stokes equations are solved using the ANSYS Fluent solver, while interface between air and water is calculated using the Volume of Fluid (VOF) method. Effect of inlet conditions regarding the Froude and Reynolds numbers, channel slope and filling ratio on the length of flow development is investigated while both sub-critical and super-critical inlet conditions are considered. Results of the numerical calculations show that uniform open channel flow is guaranteed roughly 110 and 60 diameters downstream the pipe inlet, for smooth and corrugated pipes, respectively. The transitory length shows a tendency to decrease with the Reynolds number, contrary to the entrance length in pipe flow.

Submarine landslides and mass movements in deep water caused by the 2024 Noto Peninsula earthquake, Japan

On January 1, 2024, a magnitude 7.6 earthquake struck the Noto Peninsula in Ishikawa Prefecture, central Japan. The strong shaking in the vicinity of the epicenter, where a steep submarine channel is located, suggested the occurrence of submarine landslides. To identify earthquake-induced submarine landslides east of the Noto Peninsula for the first time, we collected new bathymetric data in February 2024, one month after the earthquake, and compared it with earlier bathymetric data collected in May 2023, seven months prior to the quake. This pre- and post-earthquake comparison successfully revealed substantial negative depth changes, indicating the presence of submarine landslides along the submarine channel. The slides occurred on the flank of the submarine channel, 30 km east of the Noto Peninsula. One of the slide areas measures 1.4 km × 1.1 km at water depths of 1540–1700 m. The slide features distinct headwall scarps with a relief of up to 50 m. The originally depressed seafloor at the base of the slide exhibited positive depth changes of up to 25 m, indicating the deposition of sliding materials. The estimated volumes of slides and deposits in one of the slide areas are 18.7 × 106 m3 and 4.7 × 106 m3, respectively. This result indicates that 25% of the sliding materials were deposited in the depressions, while 75% of the materials that overflowed the depressions were transported away from the slide area. Changes in seafloor depths and acoustic backscatter intensity around the slide areas provide evidence of mass movements and depositions. The channel floor below the slide areas rose by up to 4 m, indicating material deposits. Additionally, the backscatter intensity decreased after the earthquake. These changes in backscatter intensity suggest that the seafloor was initially covered by harder, coarse-grained materials before the earthquake but had been replaced by softer, fine-grained materials afterward. These observations indicate that turbidity currents, influenced by nearby submarine landslides, transported muddy sediments across the gently sloping channel floor. Given that the 2024 Noto Peninsula earthquake is the only major earthquake with a magnitude greater than six during the nine months we analyzed the bathymetry, it is clear that the slides and mass movements were triggered by this earthquake. This study offers new insights into the characteristics of submarine landslides and mass movements induced by a single earthquake event in deep waters.

GDBM: A database of global drainage basin morphology.

Rivers and their drainage basins are fundamental landscape units, and their morphology is a record of the cascade of geologic, tectonic, biological, and climatic processes acting upon them. Quantifying this cascade depends on morphometric measurements of rivers and drainage basins, and comparison of these measurements across diverse landscape settings. Here we present a new near-Global dataset of Drainage Basin Morphology, GDBM, which provides morphometric measurements of 254,966 basins and the longest river channel within them. This dataset is created by extracting channels from the 30-meter resolution Shuttle Radar Topography Mission (SRTM) topographic data which fall within Köppen-Geiger climate zones, to allow the influence of climate on river and basin morphology to be quantified. GDBM contains measurements of channel length, slope, relief, normalised concavity, basin area, basin shape and aridity. These data have been generated with minimal assumptions, focusing on identifying and classifying channels with high confidence, through the use of a conservative drainage area threshold. GDBM provides opportunities for rapid spatial analysis of channel morphology at a near-global scale and has the potential to yield continuing insight into landscape evolution across diverse climate regimes. This dataset also has potential applications across a range of Earth and environmental science domains, through the integration of additional data on, for example, forest canopy height, landcover, or soil properties to explore the spatial variability of channel and basin properties with climate.

Temporal and spatial changes in style of accretion at the bend of a sinuous turbidite slope channel (channel–levee Complex 5, Tachrift System of NE Morocco)

Abstract This outcrop study describes variously accreted deposits constituting the fill of a sinuous channel from the Tachrift System (upper Miocene of the Taza–Guercif Basin, NE Morocco). Detailed correlation of fifty-nine logs from three outcrops spanning a left-turning bend allow recognition of four stratigraphic units recording channel establishment and levee development, aggradation and bend translation and expansion, and switching of the parent channel. Results show that lateral-accretion packages (LAPs) formed at the inner bank represent the main intra-channel depositional element, co-occurring with equally sandstone-rich and coarse-grained deposits accreted at the outer bank. The best-exposed and larger example of LAPs occurs in two correlated exposures c. 500 meters apart along-stream, which most likely straddle the bend apex. In the upstream outcrop, cut-and-fill features and sandstone amalgamation make it difficult to recognize lateral accretion. Here, LAPs consist of bedsets of amalgamated sandstones bounded by thalweg-dipping erosional surfaces that are lined up with mud-clast breccias in the deeper part of the channel fill. In the downstream outcrop, the correlated LAPs become lithologically more layered along most of their profile. Moving up the accretion dip, to the LAP top, they comprise finer-grained, and more structured sandstones alternating with mudstones. In the downstream outcrop, LAPs transition into a mud-rich heterolithic deposit characterized by trough-cross inclined stratification, which dips at a high angle to mean downstream paleocurrent. This deposit extends over a distance of a few hundred meters, straddling the inner- to outer-bank transition, and is interpreted as the expression of bank-attached bars (here termed turbidite counter-bars) forming in a flow separation zone. This study provides insights into longitudinal heterogeneity of LAPs and lithological composition of outer-bank bars and turbidite counter bars never before observed at outcrop.