Download Free Introductory Chapter Morphodynamic Model For Predicting Beach Changes Based On Bagnolds Concept And Its Applications Book in PDF and EPUB Free Download. You can read online Introductory Chapter Morphodynamic Model For Predicting Beach Changes Based On Bagnolds Concept And Its Applications and write the review.

Introductory Chapter: Morphodynamic Model for Predicting Beach Changes Based on Bagnold's Concept and Its Applications.
The authors have developed models for predicting beach changes applicable to various problems on real coasts. One of them is the contour-line-change model to predict long-term beach changes caused by the imbalance in longshore sand transport, which is a kind of N-line model. Because the calculation of the nearshore current is not needed in this model, and the computational load is small, it has an advantage in the prediction of long-term topographic changes on an extensive coast. However, the handling of boundary conditions becomes difficult when offshore coastal structures are constructed in a complicated manner, and in this regard the so-called 3D model has an advantage. Taking this point into account, the authors developed a morphodynamic model (BG model) by applying the concept of the equilibrium slope and the energetics approach, in which depth changes on 2D horizontal grids are calculated.
The BG model (a model for predicting 3D beach changes based on the Bagnold's concept) was introduced, and the fundamental aspects of the model were explained. The BG model is based on the concepts such as (1) the contour line becomes orthogonal to the wave direction at any point at the final stage, (2) similarly, the local beach slope coincides with the equilibrium slope at any point, and (3) a restoring force is generated in response to the deviation from the statically stable condition, and sand transport occurs owing to this restoring force. The same concept has been employed in the contour-line-change model and N-line model. In these studies, the movement of certain contour lines was traced, but in the BG model, 3D beach changes were directly calculated.
Grounded in current research, this second edition has been thoroughly updated, featuring new topics, global examples and online material. Written for students studying coastal geomorphology, this is the complete guide to the processes at work on our coastlines and the features we see in coastal systems across the world.
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.
Beaches in Japan have been eroding since the 1970s as a result of the artificial land alterations. Approximately 3000 fishing ports and 1000 commercial ports have been built nationwide, as well as 2532 large dams being constructed in the upstream basins of large rivers. Due to the port and dam developments, fluvial sand supply has significantly reduced resulting in shoreline recession around the river mouths. Continuous sand supply along the coastline has also been obstructed by the port breakwaters. The formation of wave shelter zone by the port breakwaters induce longshore sand transport, thereby leading to an accretion of large amount of sand in the wave shelter zone and erosion in the surrounding area. Thus, almost all causes of the beach erosion in Japan are due to anthropogenic factors. The exact situation of the beach erosion has never been clear in literatures that are written in Japanese, or in English. Coastal engineers can and should learn from these results, otherwise the same situation and problems, which were induced by excessive coastal development without protection measures and due attention given to nearby coasts, will recur throughout the world. Textbooks on coastal engineering, that were already published, describe only the theoretical fundamentals of the subject, but lack the practical perspectives and field studies. The book examines many coastal areas as examples, highlighting the various erosion factors which should be avoided elsewhere globally. This book was first published in Japanese in 2004, and was translated into English by the present author.
Effective coastal engineering is expensive, but it is not as costly as neglect or ineffective intervention. Good practice needs to be based on sound principles, but theoretical work and modelling also need to be well grounded in practice, which is continuously evolving. Conceptual and detailed design has been advanced by new industry publications since the publication of the second edition. This third edition provides a number of updates: the sections on wave overtopping have been updated to reflect changes brought in with the recently issued EurOtop II manual; a detailed worked example is given of the calculation of extreme wave conditions for design; additional examples have been included on the reliability of structures and probabilistic design; the method for tidal analysis and calculation of amplitudes and phases of harmonic constituents from water level time series has been introduced in a new appendix together with a worked example of harmonic analysis; and a real-life example is included of a design adapting to climate change. This book is especially useful as an information source for undergraduates and engineering MSc students specializing in coastal engineering and management. Readers require a good grounding in basic fluid mechanics or engineering hydraulics, and some familiarity with elementary statistical concepts.
Introduces beach processes within an approach that balances an engineering perspective against a purely geological one. Provides an up-to-date review of the current understanding of beach processes as well as applications to solve coastal problems (erosion, management issues, etc.). Discusses issues related to beach erosion and other processes. The second edition of Beach Processes and Sedimentation has been updated to include information gathered from two decades of science and engineering in the field, reflecting the vast increase in knowledge since the first edition. Discusses the rise of coastal zone management as well as patterns of wave transformations and dissipation within the surf zone, and how these water motions produce cross-shore movements of sediment resulting in beach-profile variations. An essential reference book for many readers: from beach front property owners to politicians contending with beachfront erosion to engineers addressing beachfront reclamation projects.
Provides guidance on selected techniques for the measurement of particles moving in the fluvial environment. The potential user is directed in the selection of an appropriate technique through the presentation of operating principles, application guidelines and estimated costs.