Special Issue "Modelling of River Flows, Sediment and Contaminants Transport"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Water Erosion and Sediment Transport".

Deadline for manuscript submissions: closed (31 July 2021) | Viewed by 6924

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Special Issue Editor

Dr. Bommanna Krishnappan
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Guest Editor
Retired Research Scientist, National Water Research Institute, Environment Canada, Burlington, ON, Canada
Interests: river dynamics; cohesive sediment transport; environmental hydraulics; mathematical modelling; diffusion and dispersion processes; water quality
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Special Issue Information

Dear Colleagues,

Land use activities such as mining, forestry, agriculture, and urban development often result in the production of sediment and contaminants that are transported downstream by rivers and streams in the watershed. A better understanding of the transport capacity of river flows, the interaction between sediment and contaminants, and the behavior of sediment in different flow fields are essential for assessing the environmental impacts of the human activities in the watershed. Tremendous progress has been made in recent years in developing mathematical models of river flows and sediment and contaminant transport; however, more work needs to be done in this area. For example, modelling of morphological changes of river under various flow conditions are not well developed. Cohesive sediment transport processes such as flocculation, consolidation, and entrapment need further research, and the interaction between sediment and contaminants is not fully understood. The Special Issue on modelling river flows, sediment, and contaminant transport aims to gather high-quality papers that improve the state-of-the art. Submitted papers will go through a peer-review process performed by independent reviewers. Original case studies and review papers are invited for this Special Issue.

Dr. Bommanna Krishnappan
Guest Editor

Manuscript Submission Information

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Keywords

  • river dynamics
  • sediment transport
  • contaminant transport
  • mathematical modelling
  • human impact
  • environmental impact assessment
  • water quality

Published Papers (6 papers)

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Editorial

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Editorial
Modelling of River Flows, Sediment and Contaminants Transport
Water 2022, 14(4), 649; https://doi.org/10.3390/w14040649 - 19 Feb 2022
Viewed by 406
Abstract
Economic development projects in river basins, involving mining, forestry, agriculture and urban developments, invariably impact the aquatic ecosystems of the basin [...] Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)

Research

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Article
A New Framework for Modelling Fine Sediment Transport in Rivers Includes Flocculation to Inform Reservoir Management in Wildfire Impacted Watersheds
Water 2021, 13(17), 2319; https://doi.org/10.3390/w13172319 - 24 Aug 2021
Cited by 4 | Viewed by 1281
Abstract
Fine-grained cohesive sediment is the primary vector for nutrient and contaminant redistribution through aquatic systems and is a critical indicator of land disturbance. A critical limitation of most existing sediment transport models is that they assume that the transport characteristics of fine sediment [...] Read more.
Fine-grained cohesive sediment is the primary vector for nutrient and contaminant redistribution through aquatic systems and is a critical indicator of land disturbance. A critical limitation of most existing sediment transport models is that they assume that the transport characteristics of fine sediment can be described using the same approaches that are used for coarse-grained non-cohesive sediment, thereby ignoring the tendency of fine sediment to flocculate. Here, a modelling framework to simulate flow and fine sediment transport in the Crowsnest River, the Castle River, the Oldman River and the Oldman Reservoir after the 2003 Lost Creek wildfire in Alberta, Canada was developed and validated. It is the first to include explicit description of fine sediment deposition/erosion processes as a function of bed shear stress and the flocculation process. This framework integrates four existing numerical models: MOBED, RIVFLOC, RMA2 and RMA4 using river geometry, flow, fine suspended sediment characteristics and bathymetry data. Sediment concentration and particle size distributions computed by RIVFLOC were used as the upstream boundary condition for the reservoir dispersion model RMA4. The predicted particle size distributions and mass of fine river sediment deposited within various sections of the reservoir indicate that most of the fine sediment generated by the upstream disturbance deposits in the reservoir. Deposition patterns of sediment from wildfire-impacted landscapes were different than those from unburned landscapes because of differences in settling behaviour. These differences may lead to zones of relatively increased internal loading of phosphorus to reservoir water columns, thereby increasing the potential for algae proliferation. In light of the growing threats to water resources globally from wildfire, the generic framework described herein can be used to model propagation of fine river sediment and associated nutrients or contaminants to reservoirs under different flow conditions and land use scenarios. The framework is thereby a valuable tool to support decision making for water resources management and catchment planning. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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Article
3D Numerical Simulation of Gravity-Driven Motion of Fine-Grained Sediment Deposits in Large Reservoirs
Water 2021, 13(13), 1868; https://doi.org/10.3390/w13131868 - 04 Jul 2021
Cited by 1 | Viewed by 1005
Abstract
Deposits in dam areas of large reservoirs, which are commonly composed of fine-grained sediment, are important for reservoir operation. Since the impoundment of the Three Gorges Reservoir (TGR), the sedimentation pattern in the dam area has been unexpected. An integrated dynamic model for [...] Read more.
Deposits in dam areas of large reservoirs, which are commonly composed of fine-grained sediment, are important for reservoir operation. Since the impoundment of the Three Gorges Reservoir (TGR), the sedimentation pattern in the dam area has been unexpected. An integrated dynamic model for fine-grained sediment, which consists of both sediment transport with water flow and gravity-driven fluid mud at the bottom, was proposed. The incipient motion driven by gravity in the form of fluid mud was determined by the critical slope. Shallow flow equations were simplified to simulate the gravity-driven mass transport. The gravity-driven flow model was combined with a 3D Reynolds-averaged water flow and sediment transport model. Solution routines were developed for both models, which were then used to simulate the integral movement of the fine-grained sediment. The simulated sedimentation pattern agreed well with observations in the dam area of the TGR. Most of the deposits were found at the bottom of the main channel, whereas only a few deposits remained on the bank slopes. Due to the gravity-driven flow of fluid mud, the deposits that gathered in the deep channel formed a nearly horizontal surface. By considering the gravity-driven flow, the averaged error of deposition thickness along the thalweg decreased from −13.9 to 2.2 m. This study improved our understanding of the mechanisms of fine-grained sediment transport in large reservoirs and can be used to optimize dam operations. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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Article
Sediment Balance Estimation of the ‘Cuvette Centrale’ of the Congo River Basin Using the SWAT Hydrological Model
Water 2021, 13(10), 1388; https://doi.org/10.3390/w13101388 - 16 May 2021
Cited by 1 | Viewed by 1250
Abstract
In this study, the SWAT hydrological model was used to estimate the sediment yields in the principal drainage basins of the Congo River Basin. The model was run for the 2000–2012 period and calibrated using measured values obtained at the basins principal gauging [...] Read more.
In this study, the SWAT hydrological model was used to estimate the sediment yields in the principal drainage basins of the Congo River Basin. The model was run for the 2000–2012 period and calibrated using measured values obtained at the basins principal gauging station that controls 98% of the basin area. Sediment yield rates of 4.01, 5.91, 7.88 and 8.68 t km−2 yr−1 were estimated for the areas upstream of the Ubangi at Bangui, Sangha at Ouesso, Lualaba at Kisangani, and Kasai at Kuto-Moke, respectively—the first three of which supply the Cuvette Centrale. The loads contributed into the Cuvette Centrale by eight tributaries were estimated to be worth 0.04, 0.07, 0.09, 0.18, 0.94, 1.50, 1.60, and 26.98 × 106 t yr−1 from the Likouala Mossaka at Makoua, Likouala aux Herbes at Botouali, Kouyou at Linnegue, Alima at Tchikapika, Sangha at Ouesso, Ubangi at Mongoumba, Ruki at Bokuma and Congo at Mbandaka, respectively. The upper Congo supplies up to 85% of the fluxes in the Cuvette Centrale, with the Ubangi and the Ruki contributing approximately 5% each. The Cuvette Centrale acts like a big sink trapping up to 23 megatons of sediment produced upstream (75%) annually. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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Review

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Review
Review of a Semi-Empirical Modelling Approach for Cohesive Sediment Transport in River Systems
Water 2022, 14(2), 256; https://doi.org/10.3390/w14020256 - 16 Jan 2022
Cited by 2 | Viewed by 780
Abstract
In this paper, a review of a semi-empirical modelling approach for cohesive sediment transport in river systems is presented. The mathematical modelling of cohesive sediment transport is a challenge because of the number of governing parameters controlling the various transport processes involved in [...] Read more.
In this paper, a review of a semi-empirical modelling approach for cohesive sediment transport in river systems is presented. The mathematical modelling of cohesive sediment transport is a challenge because of the number of governing parameters controlling the various transport processes involved in cohesive sediment, and hence a semi-empirical approach is a viable option. A semi-empirical model of cohesive sediment called the RIVFLOC model developed by Krishnappan is reviewed and the model parameters that need to be determined using a rotating circular flume are highlighted. The parameters that were determined using a rotating circular flume during the application of the RIVFLOC model to different river systems include the critical shear stress for erosion of the cohesive sediment, critical shear stress for deposition according to the definition of Partheniades, critical shear stress for deposition according to the definition of Krone, the cohesion parameter governing the flocculation of cohesive sediment and a set of empirical parameters that define the density of the floc in terms of the size of the flocs. An examination of the variability of these parameters shows the need for testing site-specific sediments using a rotating circular flume to achieve a reliable prediction of the RIVFLOC model. Application of the model to various river systems has highlighted the need for including the entrapment process in a cohesive sediment transport model. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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Review
Effects of River-Ice Breakup on Sediment Transport and Implications to Stream Environments: A Review
Water 2021, 13(18), 2541; https://doi.org/10.3390/w13182541 - 16 Sep 2021
Cited by 3 | Viewed by 1013
Abstract
During the breakup of river ice covers, a greater potential for erosion occurs due to rising discharge and moving ice and the highly dynamic waves that form upon ice-jam release. Consequently, suspended-sediment concentrations can increase sharply and peak before the arrival of the [...] Read more.
During the breakup of river ice covers, a greater potential for erosion occurs due to rising discharge and moving ice and the highly dynamic waves that form upon ice-jam release. Consequently, suspended-sediment concentrations can increase sharply and peak before the arrival of the peak flow. Large spikes in sediment concentrations occasionally occur during the passage of sharp waves resulting from releases of upstream ice jams and the ensuing ice runs. This is important, as river form and function (both geomorphologic and ecological) depend upon sediment erosion and deposition. Yet, sediment monitoring programs often overlook the higher suspended-sediment concentrations and loads that occur during the breakup period owing to data-collection difficulties in the presence of moving ice and ice jams. In this review paper, we introduce basics of river sediment erosion and transport and of relevant phenomena that occur during the breakup of river ice. Datasets of varying volume and detail on measured and inferred suspended-sediment concentrations during the breakup period on different rivers are reviewed and compared. Possible effects of river characteristics on seasonal sediment supply are discussed, and the implications of increased sediment supply are reviewed based on seasonal comparisons. The paper also reviews the environmental significance of increased sediment supply both on water quality and ecosystem functionality. Full article
(This article belongs to the Special Issue Modelling of River Flows, Sediment and Contaminants Transport)
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