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Sediment Transport Processes and their Modelling Applications is a book which covers a wide range of topics. The effective management of many aquatic environments, requires a detailed understanding of sediment dynamics. This has both environmental and economic implications, especially where there is any anthropogenic involvement. Numerical models are often the tool used for predicting the transport and fate of sediment movement in these situations, as they can estimate the various spatial and temporal fluxes. However, the physical sedimentary processes can vary quite considerably depending upon whether the local sediments are fully cohesive, non-cohesive, or a mixture of both types. For this reason for more than half a century, scientists, engineers, hydrologists and mathematicians have all been continuing to conduct research into the many aspects which influence sediment transport. These issues range from processes such as scour, erosion and deposition, to how sediment process observations can be applied in sediment transport modelling frameworks. This book reports the findings from recent research in applied sediment transport which has been conducted in a wide range of aquatic environments. The research was carried out by researchers who specialise in the transport of sediments and related issues.
As reservoir sedimentation has proven to be a serious problem in South Africa, research in this field has been ongoing for more than 70 years. This publication emanates from extensive research which has been undertaken over the past 30 years with the support of the South African Department of Water and Sanitation as well as the South African Water Research Commission. A great deal of information has fortunately also been obtained from China. Given the universal nature of hydraulic formulae it is not surprising, yet gratifying, that Chinese and South African data generally conform to the same mathematical relationships. This indicates that these relationships should be applicable in other countries as well. Much of the information contained here has been condensed from a more comprehensive publication. This ICOLD Bulletin follows on Bulletin 115 “Dealing with reservoir sedimentation”, which gave guidelines for management of reservoirs to limit sedimentation. The guidelines on mathematical modelling of sediment transport dynamics in reservoirs in this document can be used during the planning and design of new dams, as well as for the management of existing dams. Comme la sédimentation dans les réservoirs s'est avérée être un problème sérieux en Afrique du Sud, la recherche dans ce domaine est en cours depuis plus de 70 ans. Cette publication émane de la recherche étendue qui a été menée au cours des 30 dernières années avec l'appui du ministère sud-africain de l’eau et de l’assainissement, ainsi que de la commission sud-africaine de recherche sur l'eau. Un grand nombre d'informations ont également été obtenues de la part de la Chine. Étant donné le caractère universel de formules hydrauliques, il n'est pas surprenant, mais très gratifiant, que les données chinoises et sud-africaines se conforment généralement aux mêmes relations mathématiques. Ceci indique que ces relations devraient être applicables dans d'autres pays également. Une grande partie de l'information contenue ici a été condensée à partir d'une publication plus complète. Ce bulletin CIGB fait suite au bulletin 115 "Traité sur la sédimentation dans les réservoirs", qui a donné des directives pour la gestion des réservoirs en vue de limiter la sédimentation. Les directives sur la modélisation mathématique de la dynamique de transport des sédiments dans les réservoirs de ce présent document peuvent être utilisées lors de la planification et la conception de nouveaux barrages et pour la gestion des barrages existants.
"This book focuses on the fundamentals of sediment transport in surface waters. It covers sediment properties, open channel flows, sediment particle settling, incipient motion, bed forms, bed load, suspended load, total load, cohesive sediments, water-sediment two-phase flows, hyperconcentrated flows, debris flows, wave-induced sediment transport, turbidity currents, and physical modeling. Besides the primary context of river sedimentation, this book extensively covers sediment transport under coexisting waves and currents in coasts and estuaries, hyperconcentrated and debris flows in rivers, as well as turbidity currents in lakes, reservoirs, channels and the ocean. It includes a chapter on the water-sediment two-phase flow theory, which is considered the basis of many sediment transport models. It introduces some special topics emerged in recent years, such as transport of mixed cohesive and noncohesive sediments, transport of biofilm-coated sediments, and transport of infiltrated sand within gravel and cobble beds. The text merges the classical and new knowledge of sediment transport from various sources in English and non-English literature. It includes important contributions made by many scientists and engineers from all over the world. It balances the breadth, depth, fundamental importance, practical applicability, and future advancement of the covered knowledge. It can be used as a text and reference book. The chapters are arranged in a sequence for teaching purposes. Certain homework problems are prepared, which also highlight the important topics for instructors to select. Solutions to homework problems are available by request"--
It is evident, that for a number of ecological and technical problems in rivers and lakes a better knowledge of sediment transport and sedimentation is needed together with the ability to predict and simulate sediment behaviour. On the other hand, a stagnation of research in these topics could be observed in the last decades. At the Symposium an attempt was made to present new results in mathematics and natural sciences relevant for the sediment problem. New strategies were discussed to tackle the complexity of the problem. Basic theoretical research and laboratory experiments alone are incomplete without a feedback from field observations and measurements. For that reason well-known researchers from both basic and engineering sciences were invited. Turbulence, non-local phenomena, stability, interaction, feedback systems, self-organization, two-phase flow and chaotic processes, numerical simulations as well as measurement techniques and field results were the keywords of the Symposium. This proceedings are a good source for those interested in the state of the art.
Climate and anthropogenic changes impact the conditions of erosion and sediment transport in rivers. Rainfall variability and, in many places, the increase of rainfall intensity have a direct impact on rainfall erosivity. Increasing changes in demography have led to the acceleration of land cover changes in natural areas, as well as in cultivated areas, and, sometimes, in degraded areas and desertified landscapes. These anthropogenized landscapes are more sensitive to erosion. On the other hand, the increase in the number of dams in watersheds traps a great portion of sediment fluxes, which do not reach the sea in the same amount, nor at the same quality, with consequences on coastal geomorphodynamics. This book is dedicated to studies on sediment fluxes from continental areas to coastal areas, as well as observation, modeling, and impact analysis at different scales from watershed slopes to the outputs of large river basins. This book is concentrated on a number of keywords: “erosion” and “sediment transport”, “model” and “practice”, and “change”. The keywords are briefly discussed with respect to the relevant literature. The contributions in this book address observations and models based on laboratory and field data, allowing researchers to make use of such resources in practice under changing conditions.
This thesis aims to contribute to a better understanding of turbulent open channel flow, sediment erosion and sediment transport. The thesis provides an analysis of high-fidelity data from direct numerical simulation of (i) open channel flow over an array of fixed spheres, (ii) open channel flow with mobile eroding spheres, (iii) open channel flow with sediment transport of many mobile spheres. An immersed boundary method is used to resolve the finite-size particles.
This book treats the subject of sediment transport in the marine environment, covering transport of non-cohesive sediment by waves and current in- and outside the surf zone. It can be read independently, but a background in hydraulics and basic wave mechanics is required. It is intended for M.Sc. and Ph.D. students. The primary aim of the book is to describe the physical processes of sediment transport and how to represent them in mathematical models. It does not present a large number of different formulae for the sediment transport rates under various conditions. The book can be divided in two main parts; in the first, the relevant hydrodynamic theory is described; in the second, sediment transport and morphological development are treated. The hydrodynamic part contains a review of elementary theory for water waves, chapters on the turbulent wave boundary layer and the turbulent interaction between waves and currents, and finally, surf zone hydrodynamics and wave driven currents. The part on sediment transport introduces the basic concepts (critical bed shear stress, bed load, suspended load and sheet layer, near-bed concentration, effect of sloping bed); it treats suspended sediment in waves and current and in the surf zone, and current and wave-generated bed forms. Finally, the modelling of cross-shore and long-shore sediment transport is described together with the development, of coastal profiles and coastlines.
Introductory concepts and historical background - River morphology and river response - Basic concepts of hydraulics of open channels - Properties of sediment - Forms of bed roughness - Resistance to flow - Beginning of motion and design of stable channels - The motion of bed material - Degradation, aggradation and local scour in alluvial channels.