River Training Structures Research Articles

Comparison of hybrid deep learning models for estimation of the time-dependent scour depth downstream of river training structures

Submerged weirs, mainly positioned downstream of bridges, play a key role in safeguarding against floods and long-term scour damage. However, the structural stability of these structures could be threatened by local scour holes. This study evaluates five deep learning algorithms—Deep Neural Networks, Convolutional Neural Networks (CNNs), Convolutional Extreme Gradient Boosting (CXGB), convolutional extremely randomized trees regression, and Self-Attention-based Convolutional Neural Network (SA-CNN) in predicting the evolution of scour depth. Using Hyperband and Bayesian optimization, the models were fine-tuned for maximum accuracy. Additionally, this study investigates the impact of two data splitting methods, including random pointwise sampling and case-wise sampling on model performance. Results indicate that the hybrid CXGB and the SA-CNN models outperform other models in terms of accuracy of the estimation of the time-dependent scour depth with R2 = 0.997 in pointwise and R2 = 0.878 in case-wise split strategies, respectively. This not only demonstrates the effectiveness of these sophisticated algorithms in time-dependent scour estimation but also clarifies the effects of various data sampling techniques on model performance. Finally, the contribution of features in provided estimations is discussed utilizing SHapley Additive exPlanations values. Results indicated that the time (T) and the ratio of the flow velocity to critical velocity U0/Uc had the greatest effect on the model outputs, while side slopes indicated a negligible effect on model output compatible with the physics of the problem.

Investigating Flow around Submerged I, L and T Head Groynes in Gravel Bed

Riverbank erosion poses a significant threat to the stability and integrity of river training structures. River training structures such as groynes are important components of sustainable development as they play a crucial role in mitigating flood risks, controlling erosion, and supporting the habitat for aquatic organisms. The habitats vary largely according to the groyne type. A comprehensive comparative analysis of the flow field around the I, L, and T head groynes in the gravel bed is drawn. This study will be of immense use for riverbank protection in hilly terrain where streams are mostly dominated by the gravel bed. Laboratory experiments were conducted in a channel with a sediment bed as gravel of size 9.36 mm. Consistent flow conditions were maintained, with a flow depth (D) of 0.136 m and Froude no (Fr) of 0.61. The performance of these groynes, quantified using Lp (length of bank protection), was investigated. LHG and THG, notably, instigate more profound scour depths, recording values of 0.295 D and 0.29 D, respectively, while IHG trails with the value of 0.21 D. The complex flow field involving velocity peaks, decelerated, and negative flow is discussed and is attributed to flow separation at the groyne tip and the horseshoe vortex. The Lp for each groyne was estimated, with the IHG providing the maximum bank protection of 1.2 L1, L1 being the transverse length of the groyne. The cost–benefit analysis revealed IHG as the most cost-effective structure. These findings contribute to optimization of riverbank stabilization efforts, enhancing the resilience of hydraulic infrastructure and ensuring the safety and wellbeing of affected communities and ecosystems. The results also provide valuable insight into bank protection by various groynes and highlight their contribution to enhancing the resilience of river systems.

Evaluating the impact of porcupine systems in the flow field of the river: a hydrodynamic model study

ABSTRACT Riverbank and in-stream protection are crucial in numerous river stretches, where erosion of banks and bed material instigates river course alterations, consequently leading to land and property damage. In large Indian braided rivers like Brahmaputra, implementing tetrahedron frames commonly referred to as ‘porcupines’ has emerged as a cost-effective strategy for river training, yielding commendable outcomes in near bank sedimentation. Using flexible river training structures, such as porcupine, presents an appealing option for managing braided river channel networks in areas where permanent control structures like groynes or dams prove excessively costly or potentially ineffective, particularly in systems exhibiting highly dynamic flow regimes and morphology. This work aims to develop a hydrodynamic model that integrates the porcupine systems within its framework. The model’s effectiveness was assessed through a field test near Nematighat, Brahmaputra River, in collaboration with Assam’s Water Resources Department. The mathematical modelling provided some valuable insights regarding the flow characteristics surrounding the porcupine structure, shedding light on its hydrodynamic behaviour.

Numerical Modelling of River Training Work: A review

The construction of river training structures has a local influence on hydraulic and sediment regimes. River training is simply to modify the dimensions and patterns of channels, bars, and pools. Many scientists have applied and developed methods to identify suitable techniques for river training. In this paper 60 scientific papers were reviewed, and through this review, the researchers were divided according to the method of using the model and according to the problem that the researcher addressed, as 22% of the researchers tended to solve the sediment problem using the HEC-RAS model, and 45% of the researchers tended to solve the problem floods using the HEC- RAS model, as well as 23% of the researchers tended to refine the river section, while the last part of the researchers, who accounted for 10%, worked to solve the navigation problem by increasing the depth, and the most used model was obtained by the researchers, which is HEC- RAS, and reached. The percentage of researchers who used the model is 93%.

Numerical modeling of scour and erosion processes around spur dike

AbstractSpur dikes are popular river training structures used for flow diversion, flood control, bank protection, and improving navigation. This paper aims to study the numerical modeling of scour depth in the vicinity of a rectangular spur dike using the renormalization group (RNG) turbulence model and sedimentary van Rijn model with nested mesh configuration using FLOW‐3D. This study is also carried out to analyze the three turbulence models such as RNG, 𝑘−𝜀, and Large‐Eddy simulation (LES), for estimating the scour depth and evaluating the temporal variation of maximum scour depth. It is observed that scour depth is overpredicted with the LES model configuration used in the present study, as compared to 𝑘−𝜀 and RNG models. Furthermore, the scour depth increases by increasing the bed load coefficient near to the spur dike. Simulated results show a good agreement within a 5% error with experimental results regarding the net change of sediment elevation and scour depth.

Effects of sediment supply on scour at submerged grade control structures

Grade control structures (GCSs) are common river training structures constructed to prevent riverbed degradation. Existing scour predictors for GCSs are based on flume experiments with either no sediment supply or equilibrium sediment transport conditions, the quantitative impacts of sediment supply on the scour at submerged GCSs are still unclear. The present study reports a series of flume experiments to investigate the effects of sediment supply on scour at submerged GCSs. The experimental results show that, compared with the equilibrium sediment transport condition, a decrease of upstream sediment supply rate can reduce the upstream scour depth (down to zero), increase the downstream scour depth (maximumly by 2.3 times) and change the scour process at a submerged GCS. If the sediment supply rate is close to the sediment transport capacity of the flow, the downstream scour depth first increases rapidly and then oscillates obviously around an equilibrium value (i.e. quasi-live-bed scour). If the sediment supply rate is close to zero, the downstream scour depth oscillates initially, then increases monotonically with time towards an equilibrium value (i.e. quasi-clear-water scour). Based on the experimental data and theoretical analysis, the quantitative impacts of sediment supply rate on the equilibrium scour depth at submerged GCSs are evaluated; and calculation methods considering the sediment supply are proposed for estimating the equilibrium scour depth at submerged GCSs.

Can the regulation of Golden Inland Waterways meet the needs of navigation, flood control, and ecology? A model-based case study

In recent years, the ecological functions of inland waterways have received much attention. Roughness elements have been used in waterway regulations (WRs) to guard the riverbed and improve physical habitat. However, the response of aquatic organisms to regulations varies widely. It is controversial whether inland waterway regulations can achieve the sustainable function of navigation, flood control and ecological needs.This paper evaluated the influence of WRs on aquatic habitat by using the physical habitat simulation models combining a 2D hydrodynamic model and habitat models. Compared with a reference model with no-engineering, the habitat suitability of zoobenthos, four major species of Chinese carp's spawning ground and the Yangtze finless porpoise at different flow discharges were simulated under different densities of river training structures and types of roughness elements. Results showed that the implementation of the WRs can adjust the distribution of the suitability of aquatic habitats, but does not change the pattern of suitability with discharge. The response of biological habitats to regulation projects varied by species. Regulation can maintain the stable habitat during dry and flood periods, reducing the effect of extreme weather on aquatic organisms. Roughness elements are not suitable for large-scale use in WRs. The “win-win” agreement between economic and ecological issues can be obtained through pre-optimization.

Ship Wave–Induced Hydraulic Loading on Estuarine Groins: A Conceptual Numerical Study

River training structures, such as groynes or spur-dikes, are subject to intensifying ship-induced loads, owing to increasing ship dimensions and traffic density on waterways. In particular, the long-period primary wave system differs from other loading components, such as short-period wind waves, owing to the long wave length. To date, this loading scenario is not reflected within the empirical based design approaches for groynes. In this study, numerical approaches based on shallow water theory and computational fluid dynamics (CFD) are employed for deriving groyne design parameters, particularly by assuming stationary load conditions. Firstly, the numerical tools REEF3D::CFD and REEF3D::SFLOW are validated for the specific parameter range of ship-induced groyne overtopping based on an experimental data set. Secondly, numerical simulations at the prototype scale are connected with empirical equations for armor layer design. Comparing the results with field data from groyne prototypes indicates that the combined approach yields plausible required armor layer dimensions. Further, the examination of geometric variations of groynes confirms that a reduction in groyne slope can reduce the required armor layer dimensions by approximately 10%.

Impacts on alternate bar geometry and dynamics in a trained sand bed river

This study investigates the occurrence and dynamics of single row alternate bars forming in a particular reach of the sand bed Elbe River in Germany. Although the formation and dynamics of alternate bars have been intensively investigated in the literature, there exists only a limited number of studies focusing on the characteristics of alternate bars forming under complex field conditions. This is particular the case for bars forming in trained sand bed rivers, as most previous field studies have focused on gravel bed rivers. Moreover, little is known on the impact of river training structures on bar characteristics in anthropogenic rivers. To close this gap, we present a comprehensive bed elevation data set that was collected over a period of 10 years within a 30 km long reach of the lower Elbe River in Germany by the Federal Waterways and Shipping Administration (WSV). The reach is characterized by a sand bed, has curved as well as straight parts, and exhibits a section that is less trained by groins than the neighboring sections. For our analyses, we propose a novel approach to estimate bar characteristics based on statistically derived geometrical parameters. The outcomes of the approach are used to show that bars in Elbe River belong to the free bar type and that their origin of formation and characteristics depend on hydrological and geometrical boundary conditions. The results reveal that the active width of the river bed, defined as the distance between the groin heads, is a crucial parameter for the occurrence of alternate in the reach. We further highlight the impact of river bends on bar characteristics, as bars in the outer bend were longer and higher than their inner bend counterparts. Finally, we show that simple predictors for bar formation can be successfully applied to predict bar formation in sand bed rivers but that care needs to be taken when applying such approaches to more complex boundary conditions.

Evaluation and Effectiveness of River Training Works with Special Focus on Tinau River in Rupandehi District of Nepal

Flood in Tinau River is very common since past decades. It has damaged several houses, cultivated land and live stocks in the past and continues till the date. Hundreds of hectares of cultivated lands have been deposited with sand and debris making the land unsuitable for farming. The governments of Nepal and local bodies have been launching projects for flood control. Various types of structures were built in the past. Millions of Nepalese Rupees have been invested for river training works. However, the river training works is not functioning well. This study was conducted during the period from March 2019 to April 2020. The objective of this study is to evaluation the effectiveness of river training works with especial focus on Tinau River in Rupandehi district of Nepal. Field observation, in-depth interview, focus group discussion and questionnaire survey were the major tools used for the field investigation. The study found that the extraction of river bed materials and unmanaged catchment area are also the causes of the ineffectiveness of the river training works. It also includes lack of monitoring and supervision, socio-political pressure and lack of enforcement of law and policies. Similarly, some other causes are inadequate co-ordination between line agencies, inadequate plan and policies and lack of awareness are the minor causes of ineffective river training works. Furthermore, inadequate maintenance of built up structures, irresponsible of beneficiary group, unmanaged population growth at catchment area were also found causes behind sustainability of the river training works. The study would like to suggest that the river bed extraction should be conducted in a balanced way. And, hydrological, geological and geotechnical studies should be conducted in detail before design of the river training structures.

Numerical feasibility study for dredging and maintenance alternatives in Everett Harbor and Snohomish River

Snohomish River, which supports the third largest complex of tidally flooded estuarine and freshwater wetlands in Puget Sound, Washington, USA, delivers a large amount of sediment load to the lower estuary including the federal navigation channel and the Everett Harbor. In recent years, progressive sedimentation and diminished dredged material placement site capacity have led to economic impacts, particularly near the local service facilities maintained by the Port of Everett. An assessment of the performance of existing navigation features including jetties, dikes, and sedimentation basins was conducted using the latest generation of hydrodynamic and sediment transport numerical models to inform long-term sediment and navigation channel management decisions. This study assessed the relative merits of available alternatives for improving dredging and maintenance needs using hydrodynamic and sediment transport models: Finite Volume Community Ocean Model (FVCOM) and Adaptive Hydraulic model (AdH). In this paper, we present the refinement, setup, and calibration of morphological models using available data collected from the years 2017 and 2018 with a focus on in-channel sedimentation basins and the Port of Everett marinas. The potential for reduction in sedimentation through site-specific structure construction and repairs was evaluated. The results show that while it is feasible to modify in-channel sedimentation through river training structures, deposition at off-channel marinas along the banks and shelves may require sediment exclusion alternatives such as curtains and walls. Construction of training structures at the boat launch and reconstruction/repair of an existing training structure near the Port of Everett marinas provided promising response and merits further exploration. This study demonstrated that sediment transport simulation provided valuable information on the efficacy of proposed solutions and could help avoid unnecessary costs with alternatives likely to fail or be ineffective.

3D upstream passability of novel river training structures by migratory fish in the river Waal

Longitudinal training dams (LTDs) are novel river training structures that divide a river into a main navigation channel and protected shore channels. High velocities at the inflows of shore channels constructed in the river Waal (The Netherlands) pose a potential bottleneck for migratory fish species swimming upstream. This study assessed the passability of the inflows using flow velocity datasets from governmental monitoring campaigns collected with an ADCP during high river discharges (Q = 3489–5066 m3/s at Lobith monitoring station). The swimming performance of several migratory fish species were estimated from their total lengths (TLs). A new 3D approach to visualize the flow velocity data using Voxler® software is presented.Gasterosteus aculeatus aculeatuswas the only fish species with an adult life stage unable to pass the 9 cases tested due to its small size. The juvenile European eel and thicklip grey mullet passed 1 and 0 of the cases, respectively. The most upstream inflow, located in the inner bend of the river, was the most passable. We recommend maximizing the cross-sectional area of the inflow sills in order to reduce the flow velocities experienced by migrating fish during high river discharges. This approach may be useful to assess passability at other locations and training structures.

Assessment of scouring around spur dike in cohesive sediment mixtures: A comparative study on three rigorous machine learning models

Spur dike has been widely used as one of the river training structures to increase the stability of riverbanks and embankments. Scour around spur dikes affects their hydraulic performance and stability. Hence, the precise calculation of scour depth variation with time at spur dikes is essential to the design of safe and economical spur dikes. This study focuses on assessing the scour depth variation with time around a vertical wall spur dike in cohesive sediment mixtures using soft computing techniques based on 26 experiments performed and the data collected from existing literature. Specifically, three novel machine learning techniques including Gradient Boosting Decision Tree (GBDT), Cascaded Forward Neural Network (CFNN), and Kernel Ridge Regression (KRR) were developed for accurate prediction of scour depth at the nose and wake zones of spur dikes. An efficient best subset regression (BSR) was implemented to identify the best input combinations for two different scenarios (nose and wake scenarios). The results demonstrated that the GBDT model outperformed the CFNN and KRR models in both scenarios. In addition, the sensitivity analysis based on mutual information of datasets indicated that the clay percentage (Pc) and the ratio of cohesion to frictional angle of sediment mixture (C*/ϕ *) were the most effective variables in the nose and wake scenarios, respectively.

Scour at Bridge Piers Protected by the Riprap Sloping Structure: A Review

Bridge piers on large rivers are often protected from scouring using launchable stone, such as a riprap sloping structure. While such scour countermeasures are effective for pier protection, they significantly alter flow conditions in the bridge opening by overtopping flow and flow contraction, deflecting the formation of the scour hole downstream and exposing the downstream riverbed to additional scour. This paper provides a comprehensive and relevant review of bridge scour estimation methods for piers with a riprap sloping structure installed as a scour countermeasure. Research on empirical methods for bridge scour estimation is reviewed and analyzed with formulae used for comparable structures—complex pier formulae and formulae for river training structures. A summary of relevant formulae applicable to piers with installed scour countermeasures is provided, as well as a discussion on the possible future research directions that could contribute to the field.

Nature-based solutions for improving navigation reliability on the Madeira River, Brazil.

The Madeira River Navigation and Improvement Project provides a unique opportunity to incorporate nature-based solutions (NbS) into the built environment to promote sustainable communities and water resources infrastructure. The Madeira River has no major physical interventions (river training structures, navigation locks and dams, etc.) to improve navigation, and so is one of the world's last remaining undeveloped megarivers that exhibits natural morphological processes. The objective of this study is to create a safe, reliable, and sustainable navigation channel in the Madeira River. This is being accomplished by designing navigation improvement measures that leverage natural geomorphic processes of the river while minimizing conventional engineering practices that alter the river's morphology. To meet this objective, fluvial geomorphology analysis and hydrodynamic modeling studies have been performed to improve understanding of the morphological behavior of the system. Measures that incorporate beneficial reuse of dredged sediment within the system are being prioritized and incorporated into the study's design. Natural processes are being leveraged through the implementation of an adaptive management process to shape the navigation channel by incorporating the use of dynamic structures using natural local materials (e.g., large woody debris already in the system), a direct application of NbS in practice. This process includes extensive stakeholder collaboration and utilizing nature's energy to balance navigation, ecological, and social benefits along the Madeira River. This project demonstrates that nature-based approaches not only provide navigation benefits but can also provide ecological and social benefits in ways that are sustainable in the long term, consistent with United Nations Sustainable Development Goals (SDGs) and the International Union for the Conservation of Nature's global standard for NbS. Integr Environ Assess Manag 2022;18:115-122. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Assessing Habitat Suitability for Native and Alien Freshwater Mussels in the River Waal (the Netherlands), Using Hydroacoustics and Species Sensitivity Distributions

Longitudinal training dams (LTDs) in the river Waal are novel river training structures that protect the littoral zone from the adverse effects of navigation providing new habitats for riverine macroinvertebrates. In order to inform river management and to better understand their ecological value for native and alien mussel species, it is important to assess the habitat suitability of the protected LTD shore channels. We applied spatial hydroacoustics surveys consisting of side-scan sonar (SSS) and acoustic Doppler current profiler (ADCP) of the substrate type, water depth and flow velocity in three shore channels in combination with species sensitivity distributions (SSDs) to predict habitat suitability for native and alien mussel species. SSDs allowed for the prediction of habitat suitability as a potentially occurring fraction (POF) of a species pool. High substrate type, water depth, and near-bottom flow velocity POFs were found for ≥ 70%, 100%, and 4–51% of the total shore channel area, respectively, suggesting that shore channels provide suitable habitat for both native and alien mussel species. To enhance the shore channels as habitat for native mussel species, we recommend increasing shallow areas dominated by fine (silt/clay) and sand substrate types with low near-bottom flow velocities (near 0 m/s). In contrast, the total area of hard substrate (e.g., boulders) in the shore channels should be reduced as it strongly favored invasive alien mussel species in our study. Future research should include additional abiotic parameters to enhance the habitat suitability predictions and compare the results for different riverine habitats.

One-dimensional sediment transport modelling with Engelund–Hansen and Ackers–White transport equations for the Lower Danube River

Sediment transport can have a negative impact on riparian environments, as it can lead to the deterioration of ecological diversity and increase flood risks. Sediment transport modelling is thus a key tool in river basin management and the development of river training structures. In this study, we examined the appropriateness of 1D modelling for total sediment transport loads using the Engelund–Hansen and Ackers–White transport equations for the Lower Danube River. The study evaluated the effect of sediment grading on the accuracy of 1D model results, the appropriateness of 1D sediment transport modelling within technical or engineering projects, and the appropriateness of the Engelund–Hansen and Ackers–White equations for estimating sediment yield in the area of the Lower Danube River. The model results have been compared to field measurements, with the accuracy of the modelling results being evaluated with statistical tests. The obtained results show: (i) the sediment grading does not have a significant impact on the 1D modelling results, (ii) 1D sediment transport modelling gives sufficiently accurate results for practical engineering use (e.g. the estimation of dredging activities), and (iii) the Engelund–Hansen equation is generally better for sediment transport modelling in the Lower Danube River.

Application of hydrodynamic models for designing structural measures for river flood mitigation: the case of Kulfo River in southern Ethiopia

Flood is one of life-threatening events in different parts of Ethiopia. The causes of flood might vary from place to place, for instance, rates of deforestation, agricultural expansion, urbanization, wetland drainage, climate change, siltation of river bed, and several other types of land use change might be the cause for flood in different rivers banks. This study aims to assess, investigate, and design suitable river training works on lower Kulfo river reach. The study reach has been seriously affected by extreme floods due to the above reasons. For minimizing the loss due to flood, and to use the advantage of flood for different developmental activities various flood control measures should be adopted. The flood control measures which should more correctly be termed as “flood management” can be planed either through structural engineering measures or non-structural measures. Structural measures comprise retarding structures which store flood water, channel improvements which increase flood-carrying capacity of the river, embankments, and levees which keep the waterway from flood-prone area, detention basin which retards and absorbs most of the floodwater. Within the identified 6 km reach, field investigation including secondary data collection has been done to predict the flood extent using 1D hydrodynamic model, HECRAS and HEC Geo RAS. Estimated flood depth and extent helped us in fixing the dimension of different river training structures selected. The modelling result indicates a maximum channel bed flood depth of 4.3 m and flood plain flood depth 2.3 m obtained using a 100-year return flow. Analysis of soil samples indicates that the lower reach of Kulfo river is gravel and sand dominated meandering river, with estimated scour depth up to 3.41 m along the river course. Levees have been designed in conjunction with Groynes to protect the Upstream farm located at the prison and upper part of the Limat households. Frequent floods happening near both bridges shall be reduced by using Guide banks without influencing the bridges and diversion structures. Consideration is given for the ecosystem to stay in equilibrium, by providing suitable outer slopes so that plantation is possible on the top and side slope of the levees and guide banks.

Managing the Lower Mississippi River Landscape for Strategic Navigational and Flood Control

The Lower Mississippi River flows from the confluence of the Ohio River and Mississippi River at Cairo, Illinois into the Gulf of Mexico. Mississippi River and Ohio River pathway shifts have shaped and re-shaped the landscapes through which they flow and where their sediment-laden tributary waters co-mingle at the confluence on the voyage to the Gulf of Mexico. For much of their history, the lands adjacent to the Lower Mississippi River were bottomlands that flooded with the seasons unconstrained by human river training structures. Since 1717 European nations have fought over strategic navigational control of the Mississippi River. After the Louisiana Purchase in 1803, the United States took controlled the Lower Mississippi River. During the Civil War, from 1861-1865, the Union and Confederate forces battled for navigational control of the Lower Mississippi River. The primary objective of this paper was to highlight how the strategic navigational and flooding control of the Lower Mississippi River and geological and landscape resources were responsible for the successful economic development of this rich historical region of North America.

Two-dimensional hydraulic modelling of submerged river training structures

River training structures, such as dikes and chevrons, are commonly used for improving riparian navigation conditions. These structures are usually submerged under most flows and are aligned at variable angles to the main river flow direction. In this study, two different approaches for two-dimensional hydraulic modelling of submerged dikes and chevrons in MIKE 21 Flow Model FM have been analysed: (i) by representing the geometry of the structures explicitly in the bathymetry of the river channel (i.e. bathymetry approach), and (ii) by utilising the “dike” sub-grid module, where the flow past a structure is calculated by employing an empirical discharge relationship (i.e. dike module approach). The model results have been compared to theoretical and empirical studies, as well as to field observations and measurements. The obtained results indicate that the bathymetry approach is the more appropriate method for simulating predominantly submerged river training structures. However, these types of models should be used only for general assessment of potential river engineering solutions. For more detailed analysis of solution options, more complex models are recommended, e.g. three-dimensional hydrodynamic models.