River Channel Research Articles

Geo-spatial analyses of meandering rivers, assessing past and future impacts on bank landforms and LULC changes

ABSTRACT Morphological investigation of rivers is difficult but is one of the vital topics for the management of highly meandering river systems. The study employs GIS to analyse 32 years of Barak River data, addressing challenges in quantifying the morphology of meandering rivers. Earth observatory data from 1990 to 2022 track channel bank shifts and Land Use/Land Cover (LULC) alterations. Although the digital shoreline analysis system (DSAS) model identified long-term bank line migration analysis of shorelines, it's use is very new for rivers, especially in terms of the meandering of rivers. Conversely, research on long-term meandering river morphology in the Barak River channel has not been conducted despite evident land-use changes. Using DSAS for bank positions and CA–Markov models for LULC , future projections until 2043 reveal ongoing Barak River bank shifts and significant LULC pattern alterations. The findings of the research were validated through RMSE, Student's t-test, chi-square, and the kappa coefficient. Forecasts indicate that rapid urbanization impacts river morphology. The methodology is crucial for managing highly meandering rivers, particularly in contexts involving vulnerable river systems.

Numerical Simulations Using iRIC Nays2DH for Sediment Transport Behaviors in Dam Breach Tests

After the breach of a landslide dam, the sediment in the breach opening will be carried downstream by the breach flood. The river channel will also be eroded by the flood, resulting in bed load transport. Three large-scale dam breach tests were conducted to investigate the sediment transport behavior after a dam breach. The topography data of the creek channel were measured before and after the dam breach tests to understand the sediment transport behavior. The sediment transport simulations of the dam breach tests were conducted using the iRIC Nays2DH software. The simulations focused on three types of test setups: the single dam, single dam with a spur dike, and double dam models. The terrain (DEM) for the numerical model input was designated based on the LiDAR results, and a flow hydrograph during the dam breach tests was applied. The accuracy of the simulations was assessed using the “coverage index” and “mean absolute percentage error”. A numerical parametrical study was performed to find the major parameters that influenced the simulations. The results showed that the dynamic behavior of water flow and sediment during the dam breach processes were effectively captured by the iRIC Nays2DH simulation, but with limitations. The average flow velocity of the flood in the single dam case was the fastest among the three types of dam breaches. Due to the contraction of the creek channel caused by the spur dike, severe erosion occurred locally, and the flow rate increased in the narrowed section. Water impoundment between the two dams after the first dam breach and the consequent breach of the second dam were also well-simulated for the double dam breach. The findings and simulations in this study help explain dam breaches better and can guide researchers working on sediment transport during dam-breach floods.

Local Community Participation Seasonal Flood Disaster in Sidoarjo Regency, East Java

Irrigation in Sidoarjo Regency Drainage System Complex area of carrier channels to irrigation of the drainage (AFVOUR) in the display of water level regulators. High water surface in the channel causes slow flow of rain water catchment to a puddle. Conditions are exacerbated by backwater in the river channel in the area near the coast when the tide, causing floods to not be directly receding. Synergy has a combination of integration of various elements (for example, stakeholders) optimizing something better, legitimacy is considered to equalize perception hoping that actions are carried out in the desired action entity, appropriate according to value norms. Case Study Case data applies certain cases are generalized. Case study data is possible to be used to explore, examine comprehensiveness of a research object. Analysis of data using atlas, The weakness of the government's supervisor handles industrial waste into the River Peraul in Sidoarjo Regency, Urban Sprawl Social Impact Urbanization in big cities, controlling urbanization Increases development using the approach to touch the needs of the community needed Village, equity, spread of village remote development, the level of participation and understanding of the community provides feedback related to the concept of handling routine flood disasters every year. Seasonal flood disaster control in Sidoarjo Regency by involving local communities is an important approach by direct supervision by local communities, counseling on good water management practices, emergency response training, community based infrastructure development, coordinating between the government, local communities, form of concrete participation Local community in Sidoarjo Regency.

The Channel Migration of Inland Waterway Channels in Ilaje, Ondo State, Nigeria

The channel migration or shifting of navigable river channels have been an issue of major concern, as their effects on the transport environment, channel corridors, the manoeuvrability of vessels transiting these channels and vessels navigation amongst other factors result to inefficiency in inland transport in the riverine region of Ilaje, Nigeria. Most navigational and operational challenges have been attributable to alterations in the waterway channel due to aggradation and degradation processes in the river regime. The study’s goal is to explore channel migration along the Igbokoda-Ayetoro waterway with a view to provide mitigation methods to address potential difficulties along the waterway channel and in the adjoining environment. The objectives of the study include gathering satellite imagery of the study area between 1972 and 2022; assessing the morphological planforms of the study river channel, and assessing the river channel’s effective width using the segment-transect method. The study considered channel width, depth and alignment as indicators to be carefully evaluated to ensure safe, sustainable and efficient inland navigation measures. To ascertain the shapes and forms of the channel during the study period, geospatial and computer-aided techniques were used. Channel widths were extracted using the Segment-Transect method at 100-meter intervals. 50 year and 100-year estimate of the extent of channel/banklines shifting were determined. According to the study, there are changes in the channel’s width, depth and planform (alignment) that make the waterway indeterminate and unsuitable for vessels transiting on two-way manoeuvrability lanes. Hence, the study recommended the sustainable mitigation strategies to tackle the potential challenges pose by channel migration and reduce its impact on the vessel manoeuvrability, navigation and the adjoining environment.

Scaling Terrain-Aware Spatial Machine Learning for Flood Mapping on Large Scale Earth Imagery Data

The accurate and prompt mapping of flood-affected regions is important for effective disaster management, including damage assessment and relief efforts. While high-resolution optical imagery from satellites during disasters presents an opportunity for automated flood inundation mapping, existing segmentation models face challenges due to noises like cloud cover and tree canopies. Thanks to the digital elevation model (DEM) data readily available from sources such as United States Geological Survey (USGS), terrain guidance was utilized by recent graphical models such as hidden Markov trees (HMTs) to improve segmentation quality. Unfortunately, these methods either can only handle a small area where water levels at different locations are assumed to be consistent, or require restricted assumptions such as there is only one river channel. This paper presents an algorithm for flood extent mapping on large-scale Earth imagery, applicable to a large geographic area with multiple river channels. Since water level can vary a lot from upstream to downstream, we propose to detect river pixels in order to partition the remaining pixels into localized zones, each with a unique water level. In each zone, water at all locations flow to the same river entry point. Pixels in each zone are organized by an HMT to capture water flow directions guided by elevations. Moreover, a novel regularization scheme is designed to enforce inter-zone consistency by penalizing pixel-pairs of adjacent zones that violate terrain guidance. Efficient parallelization is made possible by coloring the zone adjacency graph to identify zones and zone-pairs that have no dependency and hence can be processed in parallel, and incremental one-pass terrain-guided scanning is conducted wherever applicable to reuse computations. Experiments demonstrate that our solution is more accurate than existing solutions, and can efficiently and accurately map out flooding pixels in a giant area of size 24,805 × 40,129. Despite the imbalanced workloads caused by a few large zonal HMTs dominating the serial computing time, our parallelization approach is effective and manages to achieve up to 14.3 × speedup on a machine with Intel Xeon Gold 6126 CPU @ 2.60GHz (24 cores, 48 threads) using 32 threads.

Metal concentration in bottom sediments for a tropical river, geological or anthropogenic source?

The study analyzes data from a survey of metal concentrations in bottom sediments from both margins (left and right) of the lower main channel of the Orinoco River. This study aims to analyze metal concentrations in the bottom sediments of the lower Orinoco River with different geological settings and anthropological sources. El Almacen (ALM), Las Galderas (G), Los Castillos de Guayana (C), Ciudad Bolivar (CB), and Ciudad Guayana (CG) were the sampling sites. Freshwater physicochemical parameters pH, conductivity, and DO were measured in situ at each sample site. Twenty-four bottom sediment samples were collected with an Eckman grab, dried, and sieved. Trace elements Pb, Cr, Cu, Cd, Ti, and Co were measured in sediments with grain sizes <63μm. Bottom sediment analysis followed EPA method 3050B (digestion with HNO3 + HCl + H2O2). Statistical analyses included the Shapiro-Wilk test, Spearman correlation, Kruskal-Wallis test, and principal component analysis (PCA). Physicochemical parameters highlighted the marked difference between the left and the right river margins, reflecting the cross-channel heterogeneity due to the dissimilar geology and low horizontal mixing. Metal concentrations were generally low, with higher variations associated with urban and industrial sources. Pb, Cr, Cu, Cd, Ba, Ti, and Co concentrations did not generally indicate significant pollution, but potential contamination from sewage and industrial effluents was noted. The differences between the two river margins were common in all the sampling sites, reflecting the sources of water biochemistry related to geochemical origins in the Andes and the Guiana Shield, respectively. The study emphasizes the importance of sampling location within the river channel.

Long-term effects of Abay River flow regulation at Lake Tana on the geomorphic and ecological responses of the downstream river channels, Upper Blue Nile basin, Ethiopia

Alluvial rivers adjust their geometry in response to environmental and anthropogenic disturbances. Flow regulation results in a new geomorphic condition that affects the aquatic ecosystem and its nature. This paper examines the long-term effects of flow regulation on the geomorphic and ecological responses of the downstream river channels of the Abay River, which is the only natural outflow of Lake Tana, Ethiopia. Since 1996, the river’s discharge regime has been affected by constructing a head-rise weir (Chara Chara) at its natural outlet for hydropower production and dam construction on the Lake Tana tributary rivers. Hydrologic data collected at the outlet of the river, SPOT, and Google Earth images were used for the study. River banks and bed topography were extracted via ArcGIS for selected study periods. The study revealed that existing water resource development on the tributary rivers of Lake Tana modified (decreased) the outflow discharge on the Abay River, and resulted a changed morphological and moderate level ecological impact on the river system. Future ongoing and planned water resource developments will exacerbate the pressure on the lake. Without careful management, these changes are likely to have severe morphological, ecological and social consequences.

REVIEWS OF PERSPECTIVES ON CONTEMPORARY APPROACHES AND TECHNIQUES IN FLUVIAL SYSTEMS EVALUATION AND MANAGEMENT

This paper reviews fluvial geomorphology perspectives and methodologies for environmental sustainability by exploring and discussing major concepts, themes, and methodologies. To meet the multidimensional aspect of fluvial geomorphology research, multidimensional approaches are now used. Fluvial geomorphology examines river channel morphology and how it is shaped by fluid flows interacting with erodible or resistant boundaries. Understanding equilibrium conditions and thresholds is key. A systems perspective is needed - any river segment is influenced by upstream and downstream conditions as part of an integrated drainage basin system. Field surveys, mapping, remote sensing, and GIS provide important morphological data on river planform, cross-sections, longitudinal profile features, sediment characteristics, etc. Statistical analysis helps detect spatial patterns and trends. Assessing channel changes over long periods is often necessary to fully understand contemporary fluvial processes and forms. Sediment storage and release causes significant time lags. Major human impacts include land use changes affecting hydrology, sediment budgets, channel boundaries; and infrastructure interrupting continuity. Sustainable management requires addressing root causes. Watershed level processes like water balances, erosion patterns, etc. strongly influence fluvial systems - coordinating river channel and upland catchment interventions is key. Models like SWAT, MIKE-SHE, and ANSWERS simulate hydrological processes but have limitations. They require robust spatial datasets spanning geology, topography, land use, climate, etc. Overall, a multidimensional, scale-conscious, historically contextualized assessment framework is required for evaluating fluvial systems. The review highlights techniques and datasets for such integrated diagnosis.

Greenhouse gas concentrations and diffusive fluxes in the middle reach of the Lancang River before and after damming

With increasing concerns of greenhouse gas (GHG) emissions from reservoirs, the debate surrounding whether hydropower qualifies as green energy has become increasingly contentious. However, quantifying the impact of dam construction on river GHG emissions still poses challenging due to the absence of direct observational data on river GHG emissions pre- and post-damming. In the present study, the differences in GHG diffusive fluxes from pre- and post-dammed river channels in the middle reaches of the Lancang River were quantified through three field campaigns in 2016, 2018, and 2023. The results indicate that reservoir construction increases the diffusive fluxes of GHG from the natural river, the total GHG emissions (expressed as carbon dioxide equivalent: CO2eq) from post-dammed river ranged from 234.42 to 527.55 mg CO2eq m−2 d−1 and were 1.4–5.2 times higher than that from pre-dammed river. However, the GHG diffusive fluxes from the reservoirs in the Lancang River remain below the average of global reservoirs. Moreover, river damming enhances the methane (CH4) emissions, the average value of CH4/CO2 ratio (in mg m−2 d−1) was 0.003 post-dam and was 13 times higher than that of pre-dam. Our results revealed that alterations in sediment distribution following reservoir construction emerge as a pivotal factor contributing to the variations in spatial distributions of GHG diffusive fluxes in the studied river channel. Overall, the findings of the study provide a primary and direct evidence of river damming impact on GHG emissions and underscore the necessity of long-term continuous in-situ measurements of GHG fluxes in the rivers undergoing hydropower development.

Sedimentation cycles, tectonic phases and progradation trends: Late Pannonian deposition in the Drmno Basin, Serbia

The Drmno Basin is characterized by siliciclastic deposition and coal accumulation during the Late Pannonian and Pliocene, which resulted in the formation of numerous coal seams that lack lateral continuity, challenging traditional research methods. The cyclicity and geometry of the coal seams suggest several phases of peat accumulation, interrupted by the influx of siliciclastic material from the Carpathians. Siliciclastic deposition began in the upper delta plain environment and developed into an alluvial plain with river channels and swamps. The coal seams in the Drmno field within the Kostolac open-cast mine show a northward shift of the peat accumulation centre and, together with the coarsening upward trend in the interburden sediments, indicate a south-northward progradation. Biostratigraphic results confirmed the progradation trend with Prosodacnomya carbonifera indicating an age of 7.5–8 Ma in the southern part of the field and with Prosodacnomya elongata indicating an age of 7.2 Ma in the northern part. The influence of recent tectonic activity in the peri-Pannonian domain is reflected by the presence of compressional tectonic structures observed in the basin fill.

Satellite observations of surface water dynamics and channel migration in the Yellow River since the 1980s

Study regionthe Yellow River (YR) in China. Study focusDue to climate change and human activities, YR channel morphology has undergone significant spatiotemporal variations. Yet, a comprehensive understanding of channel migration in YR and its driving factors remains unclear. Here, we developed a multi-index water extraction method to track the changes in surface water and river channel migration of YR based on Landsat imagery since the 1980s. New hydrological insights for the regionWe find that the average surface water area of YR over the past four decades is 4013 km2, with 73.5 % of permanent surface water. Notably, the surface water extent has experienced a 9 % increase since the 1980s, while the river channel has undergone a 12.2 % decrease. The YR channel’s centerline exhibits diverse change patterns across the entire basin, which can be broadly categorized into six types ranging from unchanged to reverse migration. We identify that climate, particularly temperature and precipitation, contributed 71 % of channel changes in the upper reaches, while 65 % of changes in the lower reaches are from human activities, including reservoir operations and water management policies. Our results unveil the variations in water extent and channel migration of the YR, offering new insights into the interactions between channel migration and climate change and human activities in the YR over the past four decades.

Comparative assessment of pollution control measures for urban water bodies in urban small catchment by SWMM

Under the current increasingly serious water pollution situation in urban, the comprehensive treatment and protecting measures in urban small catchment are the necessary step to the water pollution treatment, not only focus on the water bodies themself. In this paper, the Luojiagang river channel and its catchment in Wuhan, which has been heavily impacted by water pollution, are taken as an example for the comparative assessment of pollution control measures in order to explore the effective and sustainable schemes including the LID (Low Impact Development---LID) by using SWMM model (Storm Water Management Model---SWMM). Through the comparison of pollution treatment measures based on scenarios simulation with the baseline scenarios, it was found that the reduction effects of pollutant peak concentrations at the outlet node of Luojiagang River had the decreasing order of: the combined measures (COS) &amp;gt; LID control &amp;gt; the water diversion from Donghu Lake (WAD) &amp;gt; the sewage treatment (SET) &amp;gt; the sediment dredging (SED), and the reduction effects of total pollutant load had the decreasing order of: LID &amp;gt; COS &amp;gt; SET &amp;gt; SED &amp;gt; WAD. The results show that the control of non-point source pollution is the key for the improvement of water quality in Luojiagang River, and LID plays important role in the reduction of both pollutant peak concentrations and load. This study has the implication for the decision making of the water pollution controlling schemes in urban small catchment.

Numerical Simulations of Impact River Morphology Evolution Mechanism Under the Influence of Floodplain Vegetation

Shallow floodplains play a crucial role in river basins by providing essential ecological, hydrological, and geomorphic functions. During floods, intricate hydrodynamic conditions arise as flow exits and re-enters the river channel, interacting with the shallow vegetation. The influence and mechanism of shoal vegetation on channel hydrodynamics, bed topography, and sediment transport remain poorly understood. This study employs numerical simulations to address this gap, focusing on the Xiaolangdi–Taochengpu river section downstream of the Yellow River. Sinusoidal-derived curves are applied to represent the meandering river channel to simulate the river’s evolutionary process at a true scale. The study simulated the conditions of bare and vegetated shallow areas using rigid water-supported vegetation with the same diameter but varying spacing. The riverbed substrate was composed of non-cohesive sand and gravel. The analysis examined alterations in in-channel sediments, bed morphology, and bed heterogeneity in relation to variations in vegetation density. Findings indicated a positive correlation between vegetation density and bed heterogeneity, implying that the ecological complexity of river habitats can be enhanced under natural hydrological conditions in shallow plain vegetation and riparian diffuse flow. Therefore, for biological river restoration, vegetation planting in shallow plain regions can provide greater effectiveness.

An overview of soil and plant assessment for predicting site quality and recovery strategies of one the largest tailings dam failures worldwide.

Brazil's Fundão dam collapse is one of the world's largest disasters of tailing dam failures. Previous research has evaluated toxic metals and non-metals (Cd, Cr, Ni, Pb, As, Hg) in the same soil samples used in this study, and results have indicated that only Fe and Mn concentrations increased above the original baseline (Melo et al., 2023). Consequently, the present study's focus has shifted towards assessing and integrating changes in soil quality regarding chemical fertility and morphological, physical, and mineralogical attributes in the floodplains post-dam collapse. Soil samples from 0 to 0.2 and 0.2-0.4m depths, and samples of Urochloa sp. were collected along ten transects, spanning 100km perpendicular to the Doce River channel. This sampling strategy targeted specific landscape positions including areas affected by deposited iron tailings (DIT), soil tailing mixture (STM), and control soil (CS) devoid of iron tailing interference. Results showed no discernible alterations in Ca, Mg, K, and P concentrations in Urochloa sp., and the most severe negative impacts observed regarded the replacement of kaolinitic pre-disaster matrix for hematitic matrix, reduction in organic carbon, and the prevalence of sand and silt particles. These factors collectively contributed to triggering: (i) decrease in chemical fertility and cation exchange capacity and (ii) significant decline in physical quality, evidenced by increased density and reduced total porosity and macroporosity. Addressing these adverse effects would require the augment of organic matter levels and offset the dominance of the hematitic matrix in the DIT. Furthermore, it is imperative to decompact the DIT by mechanized or plant cultivation means.

Numerical simulation of deposit-landslide instability induced by water level decrease: a case study of RS deposit in Lancang River

Changes in reservoir water level often trigger landslides along the reservoir banks, which are common geological hazards that significantly affect the construction and operation of hydropower projects. In this paper, the stability of the RS reservoir landslide in the southwestern region of China is investigated. A discrete element seepage analysis model is constructed based on the theory of changes in the infiltration surface of the deposit caused by water level drawdown. The model is then embedded into a continuous-discontinuous three-dimensional numerical simulation method to systematically investigate the influence of reservoir water level decrease on the stability of the RS deposit. The results indicate that, under the condition of a sudden drop in reservoir water level decrease, the deposit experiences destabilization failure. Its sliding velocities are mainly influenced by seepage forces and gravity, while sliding displacements are influenced by seepage forces and topographic conditions. The landslide process shows distinct stratification characteristics. The portion of the deposit that slides into the river channel is mainly distributed between an altitude of 2655 m and 2870 m. The research results provide a scientific basis for studying the mechanism of slope failure and landslide disaster chain under the condition of reservoir water level lowering.

Risk v. reward for responsive movements by a highly mobile fish species in a flow-constrained and barrier-laden river

Context Understanding the movement behaviour of flow-dependent fish species is a foundational principle underlying the effective management of highly modified riverscapes. Aims To determine how variations in river discharge and instream barriers affect the residency, survival and movement of golden perch (Macquaria ambigua) in the degraded Gwydir River system within the northern Murray–Darling Basin. Methods We monitored the movement of 25 acoustic-tagged golden perch for up to 3 years by using a linear array spanning ~180 km of the main river channels across the lower Gwydir system. Key results Golden perch were largely sedentary for extended periods, with movements constrained by the barrier maze that now defines the system. High flows facilitated passage over instream barriers, with the highest periods of activity occurring in spring and early summer, and to a lesser extent in autumn. Conclusion Our findings are indicative of a highly constrained and isolated population of golden perch that is now likely to be neither a source nor a sink, but is in effect a false sink perpetuated by re-stocking practices. Implications The rehabilitation of the fish community in the Gwydir and other systems in similarly poor condition throughout the Murray–Darling Basin will require major institutional and societal change.

Enormous headward and gully erosion in a floodplain area reclaimed for open-cast lignite mining during the July 2021 flood in the Inde River valley (Western Germany)

BackgroundThe July flood 2021 at the mountain front of the Eifel-Ardennes Mountains and their foreland resulted in the flooding of the lignite mining area of Inden in Germany. The mining activities resulted in large-scale anthropogenic changes to the relief and fluvial system, leading to a landscape that is no longer adjusted to the recent process-response system. This paper concentrates on the Inde River, where lignite mining led to the relocation of a 5-km-long river section. The flood event resulted in the temporary avulsion of the Inde River into the former channel and, ultimately, in the flooding of the open-cast lignite mine Inden.ResultsThe flooding of the open-cast lignite mine Inden led to headwall erosion and enormous sediment mobilisation, mobilising more than half a million cubic metres of sediment within a few hours, forming a 700-m-long deeply incised channel cut. Thereby, the underlying bedrock, near-subsurface man-made structures, and former river channels influence the erosional processes to different degrees. Surface erosion is likely to be the decisive process, and subsurface erosion is likely to play a secondary role. In both cases, former channels and mill ditches were likely impacting the course of erosional processes.ConclusionsDuring high flood events open-cast mining sites in floodplains are endangered by enormous erosion and sediment transport within a short period of time (several hours). Understanding such complex erosion and depositional processes in open-cast mining areas could provide a blueprint for geomorphological processes and hazards in these anthropogenically shaped fluvial landscapes. Further, information on historic impact in the area is crucial to estimate potential risks.

Fish community dynamics following the low-head dam removal and newly installed fish passage in a headstream tributary of Jinsha River, Southwest China

Low-head dams and small hydropower developments are widely distributed in global rivers because of their high cost-efficiency and smooth implementation. However, these installations have great ecological impacts on native fish communities due to the loss of longitudinal river connectivity. Although dam removal and fishway construction are effective measures to mitigate river fragmentation, research on their effects on fish communities remains limited to date. In this study, we investigated fish community dynamics in a mountainous tributary of the Jinsha River–Heishui River following dam removal, fishway construction, and fishway renovation. Our fish sampling data from 2018 to 2023 yielded 6137 fish belonging to 25 species, 12 families, and 3 orders. The native fish community predominantly represented the typical fish fauna of the Qinghai-Tibetan Plateau, primarily including the genus Schizothorax and the families Sisoridae and Nemacheilidae. Representative fish species in the Heishui River demonstrate notable adaptations to cold water, high altitude, and rapid flow environments. After removing the Laomuhe Dam, upstream fish abundance increased sharply, but species richness slightly decreased in the short term. Fishway construction significantly enhanced species richness and abundance and reduced the difference between the upstream and downstream fish communities from the Songxin Dam. However, the subsequent fishway renovation altered the dominance of fish species, with marginal changes in community structure and abundance. Variations in fish community dynamics in the river channel and fishway structure can be attributed to differences in ecological guilds (e.g., flow preference and thermal regime) and environmental factors (e.g., flow discharge, water temperature, and water depth). The present study provides insight into the significance of mitigation measures for the impact of dams on mountainous rivers in southwest China through ecological assessment and guides for decision-making in the conservation and restoration of specific fish communities.

The importance of source data in river network connectivity modeling: A review

AbstractRiver network connectivity (RC) describes the hydrologic exchange of water, nutrients, sediments, and pollutants between the river channel and other “sites” via heterogenous flowpaths along the river corridor. As water moves downstream it carries these constituents, creating a stream‐to‐ocean continuum of connectivity that regulates global water, carbon, and nutrient cycling. River network connectivity models have developed over many decades, culminating in recent years with network‐scale RC models that explicitly simulate the transport and exchange of water and elements from headwaters to coasts, sometimes requiring models to contain tens of millions of river reaches. These advances provide transformative insights into the aggregate effects of RC on water and material transport across scales from local to global. Yet, recent reviews have pointed to several challenges that need to be overcome to continue advancing network‐scale RC modeling. In service of these goals, I summarize recent network‐scale RC maps and models to identify similarities and differences across the large‐scale RC modeling landscape. Although our computational and upscaling abilities have significantly improved and have revealed new insights, current models are still limited by the quantity, quality, resolution, and lack of standardization of the available in situ databases and source data maps necessary for the modeling. This suggests that we can extend recent advances if we keep improving these source datasets, while continuously revisiting our physics and theory to explain those new data. In doing so, we will continue to expand the role of network‐scale RC models in informing water quality modeling and management into the future.

Development of runoff generation models in the former USSR and Russia: a historical overview

The paper presents a historical overview of the development of hydrological models in the former USSR and Russia since the 1930s. An overwhelming number of hydrological papers were published in Russian, and they are not sufficiently familiar to the world hydrological community. The purpose of the review is to fill the gap and present the main achievements, some of which were pioneering for their time. The period under consideration is divided into three sub-periods. Pre-computer 1930-1950s were associated, first of all, with the development of models of unsteady water flow in river channels and linear flood-routing models; in 1960-1980s, many theoretical and practical foundations for modelling the processes of the hydrological cycle and the formation of river runoff were developed; and the Russian era following 1991, when several notable advancements in the considered field were also made.