Assessment on Morphological Changes due to Coastal Exploitations and Remedies for Coastal Defense

2017 ◽  
Author(s):  
Wei-Po Huang ◽  
Lien-Kwei Chien ◽  
Cheng-Yu Ku
Keyword(s):  
Morphological Changes ◽  
Sustainable Use ◽  
Beach Nourishment ◽  
Coastal Structures ◽  
Remedial Measure ◽  
Coastal Morphology ◽  
Local Erosion ◽  
Coastal Defense ◽  
Coastal Exploitation ◽  
Biological Environment

This study evaluates the influence of coastal structures on coastal morphology near Hsin-Chu fishery harbor in the northwest of Taiwan. As a result, the downdrift side has undergone local erosion due to the longshore sediment was impounded at updrift breakwaters resulting the enhancement of coastal flood risks as well as deterioration of the biological environment. Process and trend analyses were used to assess the effects the coastal exploitation made on the coastal morphology. Environmentally-friendly remedial measure, beach nourishment is proposed. The sediment source supply and the location of beach nourishment were also suggested for achieving the goal of sustainable use in the area.

scholarly journals Coastal Modelling Environment version 1.0: a framework for integrating landform-specific component models in order to simulate decadal to centennial morphological changes on complex coasts

2017 ◽  
Vol 10 (7) ◽  
pp. 2715-2740 ◽  
Author(s):  
Andrés Payo ◽  
David Favis-Mortlock ◽  
Mark Dickson ◽  
Jim W. Hall ◽  
Martin D. Hurst ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Simulation Models ◽  
Coastal Structures ◽  
Coastal Morphology ◽  
Novel Approach ◽  
Coastal Modelling ◽  
Coupling Approach ◽  
Modelling Environment ◽  
Alongshore Sediment Transport ◽  
Component Models

Abstract. The ability to model morphological changes on complex, multi-landform coasts over decadal to centennial timescales is essential for sustainable coastal management worldwide. One approach involves coupling of landform-specific simulation models (e.g. cliffs, beaches, dunes and estuaries) that have been independently developed. An alternative, novel approach explored in this paper is to capture the essential characteristics of the landform-specific models using a common spatial representation within an appropriate software framework. This avoid the problems that result from the model-coupling approach due to between-model differences in the conceptualizations of geometries, volumes and locations of sediment. In the proposed framework, the Coastal Modelling Environment (CoastalME), change in coastal morphology is represented by means of dynamically linked raster and geometrical objects. A grid of raster cells provides the data structure for representing quasi-3-D spatial heterogeneity and sediment conservation. Other geometrical objects (lines, areas and volumes) that are consistent with, and derived from, the raster structure represent a library of coastal elements (e.g. shoreline, beach profiles and estuary volumes) as required by different landform-specific models. As a proof-of-concept, we illustrate the capabilities of an initial version of CoastalME by integrating a cliff–beach model and two wave propagation approaches. We verify that CoastalME can reproduce behaviours of the component landform-specific models. Additionally, the integration of these component models within the CoastalME framework reveals behaviours that emerge from the interaction of landforms, which have not previously been captured, such as the influence of the regional bathymetry on the local alongshore sediment-transport gradient and the effect on coastal change on an undefended coastal segment and on sediment bypassing of coastal structures.

scholarly journals Morphodynamic Evolution of a Nourished Beach with Artificial Sandbars: Field Observations and Numerical Modeling

2021 ◽  
Vol 9 (3) ◽  
pp. 245
Author(s):  
Cuiping Kuang ◽  
Xuejian Han ◽  
Jiabo Zhang ◽  
Qingping Zou ◽  
Boling Dong
Keyword(s):  
Sediment Transport ◽  
Tidal Current ◽  
Model Simulation ◽  
Morphological Changes ◽  
Current Model ◽  
Beach Nourishment ◽  
Tidal Range ◽  
Coastal Protection ◽  
Field Observations ◽  
One Year

Beach nourishment, a common practice to replenish an eroded beach face with filling sand, has become increasingly popular as an environmentally friendly soft engineering measure to tackle coastal erosion. In this study, three 200 m long offshore submerged sandbars were placed about 200 m from the shore in August 2017 for both coastal protection and beach nourishment at Shanhai Pass, Bohai Sea, northeastern China. A series of 21 beach profiles were collected from August 2017 to July 2018 to monitor the morphological changes of the nourished beach. Field observations of wave and tide levels were conducted for one year and tidal current for 25 h, respectively. To investigate the spatial-temporal responses of hydrodynamics, sediment transport, and morphology to the presence of three artificial submerged sandbars, a two-dimensional depth-averaged (2DH) multi-fraction sediment transport and morphological model were coupled with wave and current model and implemented over a spatially varying nested grid. The model results compare well with the field observations of hydrodynamics and morphological changes. The tidal range was around 1.0 m and the waves predominately came from the south-south-east (SSE) direction in the study area. The observed and predicted beach profiles indicate that the sandbars moved onshore and the morphology experienced drastic changes immediately after the introduction of sandbars and reached an equilibrium state in about one year. The morphological change was mainly driven by waves. Under the influences of the prevailing waves and the longshore drift toward the northeast, the coastline on the leeside of the sandbars advanced seaward by 35 m maximally while the rest adjacent coastline retreated severely by 44 m maximally within August 2017–July 2018. The model results demonstrate that the three sandbars have little effect on the tidal current but attenuate the incoming wave significantly. As a result, the medium-coarse sand of sandbars is transported onshore and the background silt is mainly transported offshore and partly in the longshore direction toward the northeast. The 2- and 5-year model simulation results further indicate that shoreline salient may form behind the sandbars and protrude offshore enough to reach the sandbars, similar to the tombolo behind the breakwater.

Physical and Morphological Changes to Wetlands Induced by Coastal Structures

2017 ◽  
pp. 275-315 ◽  
Author(s):  
Germán Daniel Rivillas-Ospina ◽  
Gabriel Ruiz-Martinez ◽  
Rodolfo Silva ◽  
Edgar Mendoza ◽  
Carlos Pacheco ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Coastal Structures

COASTAL ENGINEERING 2002

2002 ◽  
Vol 1 (28) ◽  
Author(s):  
Jane McKee Smith
Keyword(s):  
Sediment Transport ◽  
Coastal Management ◽  
Physical Modeling ◽  
State Of The Art ◽  
Field Measurements ◽  
Coastal Engineering ◽  
Coastal Processes ◽  
Coastal Structures ◽  
Coastal Morphology ◽  
Coastal Waves

*** Available Only Through World Scientific *** http://www.worldscibooks.com/engineering/5165.html This book contains more than 300 papers presented at the 28th International Conference on Coastal Engineering, held in Cardiff, Wales, in July 2002. It is divided into five parts: coastal waves; nearshore currents, swash, and long waves; coastal structures; sediment transport; and coastal morphology, beach nourishment, and coastal management. The papers cover a broad range of topics, including theory, numerical and physical modeling, field measurements, case studies, design, and management. Coastal Engineering 2002 provides engineers, scientists, and planners with state-of-the-art information on coastal engineering and coastal processes.

scholarly journals Coastal vulnerability of a pinned, soft-cliff coastline, II: assessing the influence of sea walls on future morphology

2014 ◽  
Vol 2 (1) ◽  
pp. 233-242 ◽  
Author(s):  
A. Barkwith ◽  
M. D. Hurst ◽  
C. W. Thomas ◽  
M. A. Ellis ◽  
P. L. Limber ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Morphological Changes ◽  
Numerical Models ◽  
Field Research ◽  
Wave Climate ◽  
Sediment Flux ◽  
Climate Data ◽  
Coastal Morphology ◽  
Coastal Evolution ◽  
The Impact

Abstract. Coastal defences have long been employed to halt or slow coastal erosion, and their impact on local sediment flux and ecology has been studied in detail through field research and numerical simulation. The non-local impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention. Morphological changes at this scale due to defending structures can be difficult to quantify or identify with field data. Engineering-scale numerical models, often applied to assess the design of modern defences on local coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older structures. We extend previous work to explore the influences of sea walls on the evolution and morphological sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East Yorkshire, UK, is used as a case study to explore model scenarios where the coast is both defended with major sea walls and allowed to evolve naturally were there are no sea defences. Using a mesoscale numerical coastal evolution model, observed wave-climate data are perturbed linearly to assess the sensitivity of the coastal morphology to changing wave climate for both the defended and undefended scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have a greater impact on sediment flux due to increased sediment availability along this part of the coast. Multiple defence structures, including those separated by several kilometres, were found to interact with each other, producing complex changes in coastal morphology under a changing wave climate. Although spatially and temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their up-drift side.

scholarly journals Numerical Modeling of Sediment Transport Rate and Shoreline Changes of Jazireh-e Shomali-Jonoubi Port in the Persian Gulf

2020 ◽  
Vol 64 (2) ◽  
pp. 39-45
Author(s):  
Milad Bamdadi Nejad ◽  
◽  
Mohammad Javad Ketabdari ◽  
Farhad Shojaei ◽  
◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Sediment Transport ◽  
Satellite Images ◽  
Morphological Changes ◽  
Wave Climate ◽  
Coastal Structures ◽  
Shoreline Changes ◽  
The Persian Gulf ◽  
Management Operation ◽  
Good Agreement

Studying the sediments and predicting the coastal morphological changes have wide applications in coastal engineering, including coastal management, operation, and design of the structures as well as their maintenance, development, and expansion of coasts and coastal structures, which are of paramount importance. This study aims to model the shoreline changes around the Jazireh-e Shomali-Jonoubi Port, calculate the amount of advancement and recession due to the construction of the breakwater, and to determine the areas exposed to erosion and sedimentation. To this end, a series of primary information, including aerial and satellite images, hydrographic and topographic maps, and the specifications and grading of the sediment of the considered coast, has been collected and the overall morphology of the area has been determined. The input data into the model include a 12-year time series of the wave (height, period, and direction of the wave) and the wave climate. The length of the shoreline is 4 km and a profile perpendicular to the coast with a length of 1500 m has been applied to the model. Finally, using numerical modeling, the net and gross potential rates of annual and cumulative sediment transport, as well as shoreline changes after 12 years, were simulated. The effect and length of sedimentation behind the port’s breakwater after 1, 5, 10 and 12 years are 81, 190, 247 and 267 meters, respectively, which is in good agreement with the actual observations. Because the length of the breakwaters is 300 meters, the sedimentation problem has not yet been established for the port after 12 years.

scholarly journals NUMERICAL CALCULATION ON SHORELINE CONSERVATION IN MAJURO ATOLL, THE MARSHALL ISLANDS

2011 ◽  
Vol 1 (32) ◽  
pp. 94 ◽  
Author(s):  
Daisaku Sato ◽  
Hiromune Yokoki
Keyword(s):  
Morphological Changes ◽  
Beach Nourishment ◽  
Marshall Islands ◽  
Island Conservation ◽  
Severe Erosion ◽  
Effective Option ◽  
Conservation Result ◽  
Conservation Plan ◽  
Erosion And Accretion ◽  
Erosion Volume

Development of a numerical model for future estimation of morphological changes in Majuro atoll were carried out, and, at the same time, examination of beach nourishment for sustainable island conservation plan was examined by the developed model. Identified erosion and accretion area from calculated shoreline indicated that the northern tip of Laura and some areas in LongIsland had severe erosion until 100 years later as well as large accretion in northern part of the atoll. Three beach nourishment scenarios using eroded sediments, which were accreted in deep lagoon in northern part of atoll, were examined and they decreased 30% of accumulative erosion volume compared with the non-conservation result. This result shows that the beach nourishment is an effective option to sustainable island conservation plan in Majuro atoll.

scholarly journals Morphological changes due to marine aggregate extraction for beach nourishment in the German Bight (SE North Sea)

2018 ◽  
Vol 39 (1) ◽  
pp. 47-58 ◽  
Author(s):  
F. Mielck ◽  
H. C. Hass ◽  
R. Michaelis ◽  
L. Sander ◽  
S. Papenmeier ◽  
...  
Keyword(s):  
North Sea ◽  
German Bight ◽  
Morphological Changes ◽  
Beach Nourishment ◽  
Marine Aggregate

scholarly journals PROJECTING CHANGES IN COASTAL MORPHOLOGY BY SATISFYING PREREQUISITE CONDITIONS OF SLAMM SOFTWARE IN CONTEXT OF SUNDARBAN

2018 ◽  
Vol XLII-5 ◽  
pp. 503-510
Author(s):  
A. Chakraborty ◽  
A. Basu ◽  
N. Mukherjee ◽  
N. Chaudhary ◽  
K. Chakraborty
Keyword(s):  
Sea Level ◽  
Satellite Images ◽  
Morphological Changes ◽  
Satellite Image ◽  
Primary Source ◽  
Vegetation Coverage ◽  
Coastal Morphology ◽  
Rs And Gis ◽  
Gis Data ◽  
Final Output

<p><strong>Abstract.</strong> RS and GIS data have been acquired as a primary source for study. The satellite images mainly show the temporal changes in coastal morphology and shorelines of the area. The main aim is to analyze the applicability of a platform called SLAMM or Sea Level Affecting Marshes Model to predict the changes related to the different kinds of ecosystems in the Sundarbans with the eustatic rise in sea level. A satellite image (LANDSAT) of the year 2001 of the study area was used as a base map. Using this base map, an attempt has been made to forsee the morphological changes to the ecosystems up to the year 2016 using SLAMM (Payo, et al., 2016). It has investigated the changes in coastal scenario and also its effect on the vegetation and other factors of sundarban. The results indicate that tidal flats are increasing along with the year thus degrading the ocean beach and the amount of vegetation coverage, especially that of mangroves which has degraded between these years and may predict its changes up till the end of 21st century. The SLAMM software will also show the accuracy depending on the calibration and SLR depending on MSL and MTL to that of the real world scenario. Hence the final output will facilitate us with certain future scope which may help for better and bigger approaches of study towards the development of coastal management.</p>

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