scholarly journals SIMULATION OF LONG-TERM SHORELINE CHANGE DRIVEN BY LONGSHORE AND CROSS-SHORE SEDIMENT TRANSPORT

2020 ◽  
pp. 31
Author(s):  
Yan Ding ◽  
Sung-Chan Kim ◽  
Richard B. Styles ◽  
Rusty L. Permenter
Keyword(s):  
Sediment Transport ◽  
Shoreline Change ◽  
Breaking Wave ◽  
Beach Profile ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Wave Energy Flux ◽  
Semi Empirical ◽  
Evolution Modeling

Driven by wave and current, sediment transport alongshore and cross-shore induces shoreline changes in coasts. Estimated by breaking wave energy flux, longshore sediment transport in littoral zone has been studied for decades. Cross-shore sediment transport can be significant in a gentle-slope beach and a barred coast due to bar migration. Short-term beach profile evolution (typically for a few days or weeks) has been successfully simulated by reconstructing nonlinear wave shape in nearshore zone (e.g. Hsu et al 2006, Fernandez-Mora et al. 2015). However, it is still lack of knowledge on the relationship between cross-shore sediment transport and long-term shoreline evolution. Based on the methodology of beach profile evolution modeling, a semi-empirical closure model is developed for estimating phase-average net cross-shore sediment transport rate induced by waves, currents, and gravity. This model has been implemented into GenCade, the USACE shoreline evolution model.

scholarly journals Simulations of Shoreline Changes along the Delaware Coast

2021 ◽  
Author(s):  
Yan Ding ◽  
Sung-Chan Kim ◽  
Rusty L. Permenter ◽  
Richard B. Styles ◽  
Jeffery A. Gebert
Keyword(s):  
Sediment Transport ◽  
Coastal Sediments ◽  
Coastal Protection ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Technical Report ◽  
Indian River ◽  
Sediment Transfer ◽  
Island Coast

This technical report presents two applications of the GenCade model to simulate long-term shoreline evolution along the Delaware Coast driven by waves, inlet sediment transport, and longshore sediment transport. The simulations also include coastal protection practices such as periodic beach fills, post-storm nourishment, and sand bypassing. Two site-specific GenCade models were developed: one is for the coasts adjacent to the Indian River Inlet (IRI) and another is for Fenwick Island. In the first model, the sediment exchanges among the shoals and bars of the inlet were simulated by the Inlet Reservoir Model (IRM) in the GenCade. An inlet sediment transfer factor (γ) was derived from the IRM to quantify the capability of inlet sediment bypassing, measured by a rate of longshore sediments transferred across an inlet from the updrift side to the downdrift side. The second model for the Fenwick Island coast was validated by simulating an 11-y ear-long shoreline evolution driven by longshore sediment transport and periodic beach fills. Validation of the two models was achieved through evaluating statistical errors of simulations. The effects of the sand bypassing operation across the IRI and the beach fills in Fenwick Island were examined by comparing simulation results with and without those protection practices. Results of the study will benefit planning and management of coastal sediments at the sites.

scholarly journals Coastal Processes and Longshore Sediment Transport along Zemmouri Bay, Central East Coast of Algeria

2019 ◽  
Vol 21 (1) ◽  
pp. 7-15
Author(s):  
Khoudir Mezouar ◽  
Romeo Ciortan
Keyword(s):  
Sediment Transport ◽  
Morphological Changes ◽  
Shoreline Change ◽  
Spatial And Temporal Scales ◽  
Wave Refraction ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Western Area ◽  
Waves And Currents ◽  
Comprehensive Study

Abstract The coastline of Zemmouri Bay on the northeast coast of Algeria with about 50 km of shoreline has been eroding since 1970. Changes of the sandy shoreline are continuous and occur at diverse spatial and temporal scales. This erosion is a major crisis and it potentially impacts the coastal population and natural environment. In order to understand and predict these morphological changes, an accurate description of sediment transport by waves and currents and shoreline change is important. This paper presents a comprehensive study of wave refraction, current-driven sediment transport and shoreline change. Results show that the study area exhibits a great variety of shoreline evolution trends, with erosion prevailing in the eastern and central sectors and stability or even accretion in the Western area.

scholarly journals EXPERIMENTAL INVESTIGATION ON DYNAMIC EQUILIBRIUM BAY SHAPE

2012 ◽  
Vol 1 (33) ◽  
pp. 37
Author(s):  
Sutat Weesakul ◽  
Somruthai Tasaduak
Keyword(s):  
Experimental Investigation ◽  
Sediment Transport ◽  
Dynamic Equilibrium ◽  
Shoreline Change ◽  
Sediment Supply ◽  
Coastal Protection ◽  
Supply Source ◽  
Wave Condition ◽  
Longshore Sediment Transport

Equilibrium bay is a bay that its shoreline is stable and does not change with time in long term. This concept can be applied for coastal protection. Experiments on dynamic equilibrium bay planform are conducted in a laboratory. There is one location of sediment supply source into a bay near upcoast headland and its magnitude vary from case to case. Wave obliquity varies from small to moderate values. These are two main parameters while wave condition is kept constant. The final bay planforms are investigated and recorded once they reach equilibrium with condition that sediment transport gradient approaches zero and no further shoreline change are observed. The parabolic equation similar to that for static equilibrium is newly proposed. The coefficients are originally derived and found to be a function of wave obliquity and the ratio of sediment supplied into bay to longshore sediment transport. The new dynamic equilibrium bay equation can be used and applied to study morphology change with variation of supplied sediment from inland.

Numerical Simulation of Dynamic Shoreline Changes Behind a Detached Breakwater by Using an Equilibrium Formula

2017 ◽  
Author(s):  
Jung Lyul Lee ◽  
John Rong-Chung Hsu
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Shoreline Change ◽  
Beach Profile ◽  
Excellent Performance ◽  
Shoreline Changes ◽  
Shoreline Evolution ◽  
Equilibrium Beach Profile ◽  
Shape Equation ◽  
The One

Salient and tombolo are common features found in the lee of detached breakwaters. The empirical parabolic bay shape equation (PBSE) can be applied when their planform is fully developed, whereas numerical model is required to simulate the dynamic shoreline evolution prior to the planform reaching static equilibrium. This paper reports the excellent performance of PBSE through the comparison with labaratory results and the development of a numerical model for dynamic shoreline change that utilizes the concept of PBSE and equilibrium beach profile. Formulation proposed for sediment transport rate is theoretically compared with that in GENESIS. The governing equation for the combined shoreline response model is based on the one-line beach model, which includes shoreline changes owing to longshore and cross-shore sediment transport. Finally, numerical results reveal, by comparing with an experimental case in the laboratory, that the model is adequate to successively simulating the dynamic evolutions of the shoreline behind a detached breakwater.

scholarly journals LONG-TERM PREDICTION OF LONGSHORE SEDIMENT TRANSPORT IN THE CONTEXT OF CLIMATE CHANGE

2020 ◽  
pp. 15
Author(s):  
Amin Reza Zarifsanayei ◽  
Amir Etemad-Shahidi ◽  
Nick Cartwright ◽  
Darrell Strauss
Keyword(s):  
Climate Change ◽  
Sediment Transport ◽  
Climate Change Impacts ◽  
Baseline Period ◽  
Wave Climate ◽  
Total Uncertainty ◽  
Longshore Sediment Transport ◽  
Coastal Sediment Transport ◽  
Wave Energy Flux

Due to climate change impacts on atmospheric circulation, global and regional wave climate in many coastal regions around the world might change. Any changes in wave parameters could result in significant changes in wave energy flux, the patterns of coastal sediment transport, and coastal evolution. Although some studies have tried to address the potential impacts of climate change on longshore sediment transport (LST) patterns, they did not sufficiently consider the uncertainties arising from different sources in the projections. In this study, the uncertainty associated with the choice of model used for the estimation of LST is examined. The models were applied to a short stretch of coastline located in Northern Gold Coast, Australia, where a huge volume of sediment is transported along the coast annually. The ensemble of results shows that the future mean annual and monthly LST rate might decrease by about 11 percent, compared to the baseline period. The results also show that uncertainty associated with LST estimation is significant. Hence, it is proposed that this uncertainty, in addition to that from other sources, should be considered to quantify the contribution of each source in total uncertainty. In this way, a probabilistic-based framework can be developed to provide more meaningful output applicable to long-term coastal planningRecorded Presentation from the vICCE (YouTube Link): https://youtu.be/3CGU9RcGYjE

scholarly journals PROBABILISTIC SHORELINE CHANGE MODELING AND RISK ESTIMATION OF EROSION

2018 ◽  
pp. 1
Author(s):  
Yan Ding ◽  
Ashley E. Frey ◽  
Sung-Chan Kim ◽  
Rusty E. Permenter
Keyword(s):  
Monte Carlo ◽  
Sediment Transport ◽  
Shoreline Change ◽  
Likelihood Method ◽  
Random Waves ◽  
Shoreline Changes ◽  
Model Based ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Wave Heights

Prediction of long-term shoreline changes is a key task in planning and management of coastal zones and regional sediment management. Due to complex natural features of offshore waves, sediments, and longshore sediment transport, quantifying uncertainties of shoreline evolution and risks of extreme shoreline changes (erosion and accretion) is of vital importance for practicing uncertainty- or risk-based design of shorelines. This paper presents probabilistic shoreline change modeling to quantify uncertainties of shoreline variations by using numerical-model-based Monte-Carlo simulations. A shoreline evolution model, GenCade, is used to simulate longshore sediment transport and shoreline changes induced by random waves from offshore. A probability density function with a modified tail distribution is developed to capture stochastic features of wave heights under fair weather and storm conditions. It produces a time series of wave heights including small and extreme waves based on their probabilities (or frequencies of appearance). Probabilistic modeling of shoreline change is demonstrated by computing spatiotemporal variations of statistical parameters such as mean and variance of shoreline changes along an idealized coast bounded by two groins. Maximum shoreline changes in return years with a confidence range are also estimated by using maximum likelihood method. Reasonable results of obtained probabilistic shoreline changes reveal that this model-based Monte-Carlo simulation and uncertainty estimation approach are applicable to facilitate risk/uncertainty-based design and planning of shorelines.

MODELLING LONG-TERM SHORELINE EVOLUTION: FIGUEIRA DA FOZ BEACH, PORTUGAL

2017 ◽  
pp. 17
Author(s):  
Carla Pereira ◽  
Carlos Coelho ◽  
Paulo A. Silva
Keyword(s):  
Sediment Transport ◽  
Numerical Models ◽  
Shoreline Position ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Time Period ◽  
Accretion Rates ◽  
Time Periods

This work applies two different shoreline evolution numerical models (LTC and GENESIS) in two different time periods (1980 2010 and 2010-2014) to compare respectively the calibration and validation performance of the models. The models were applied to evaluate long-term shoreline position and longshore sediments transport evolution, considering as a case study a sandy beach stretch located updrift of the Figueira da Foz harbor jetty, on the Northwest Portuguese coast. Due to the jetty extension, this stretch exhibits a clear accretion trend during the analyzed time periods. For this region, the longshore sediment transport rate estimated by several authors varies between 200 and 1500x103m3/year. According to the modelling results, it was observed that both models reproduce reasonably well the shoreline evolution between 1980 and 2010. In average, the LTC model reproduces a 2010 shoreline position nearest the observed and GENESIS presents better approximation in the Northern part of the beach and also near the South (downdrift) border (just close to the Northern jetty of the harbor). The modeled shoreline average accretion rates for the considered stretch is quite similar and close to the values referred in the bibliography, which indicates that the beach presents 500 meters of maximum accretion width updrift the jetty (about 16.6m/year). In what concerns to the longshore sediment transport it was observed that numerical models generally indicate lower values than the bibliography, being GENESIS results higher and closer to the observed than the LTC. These results are common in the numerical modelling of shoreline evolution, showing that is difficult to simultaneously represent both the shoreline position and sediment transport volumes. After calibration, LTC validation was evaluated for the time period between 2010 and 2014 to allow confidence in the extrapolation of results to the future. Estimated deposition rates of about 350x103m3/year were obtained at the harbor entrance.

scholarly journals APPLICATION OF A SEMI-EMPIRICAL LONGSHORE TRANSPORT FORMULATION

2012 ◽  
Vol 1 (33) ◽  
pp. 22
Author(s):  
Giuseppe Barbaro ◽  
Giuseppe Roberto Tomasicchio ◽  
Giovanni Malara ◽  
Felice D'Alessandro
Keyword(s):  
Sediment Transport ◽  
Transport Rate ◽  
Sediment Transport Rate ◽  
Longshore Sediment Transport ◽  
Longshore Transport ◽  
Semi Empirical

The present paper deals with the determination of longshore sediment transport rate. Specifically, case study of Saline Joniche (Reggio Calabria, Italy, is discussed. This case is of interest because, in this location, an artificial basin was built in the 70’s. After few years, port entrance experienced total obstruction by sand. Actually, the area is abandoned and several projects have been proposed for revitalising port activities. This paper discusses a method for estimating the longshore sediment transport rate at Saline Joniche and complements previous methodology.

Prediction of Longshore Sediment Transport Using Soft Computing Techniques

2008 ◽  
Author(s):  
Roham Bakhtyar ◽  
David Andrew Barry ◽  
Abbas Ghaheri
Keyword(s):  
Sediment Transport ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Transport Rate ◽  
Breaking Wave ◽  
Input Output ◽  
Empirical Formulas ◽  
Inference System ◽  
Longshore Sediment Transport ◽  
Soft Computing Techniques

An important task for coastal engineers is to predict the sediment transport rates in coastal regions with correct estimation of this transport rate, it is possible to predict both natural morphological or beach morphology changes and the influence of coastal structures on the coast line. A large number of empirical formulas have been proposed for predicting the longshore sediment transport rate as a function of breaking wave characteristics and beach slope. The main shortcoming of these empirical formulas is that these formulas are not able to predict the field transport rate accurately. In this paper, an Adaptive-Network-Based Fuzzy Inference System which can serve as a basis for consulting a set of fuzzy IF-THEN rules with appropriate membership functions to generate the stipulated input-output pairs, is used to predict and model longshore sediment transport. For statistical comparison of predicted and observed sediment transport, bias, Root Mean Square Error, and scatter index are used. The results suggest that the ANFIS method is superior to empirical formulas in the modeling and forecasting of sediment transport. We conclude that the constructed models, through subtractive fuzzy clustering, can efficiently deal with complex input-output patterns. They can learn and build up a neuro-fuzzy inference system for prediction, while the forecasting results provide a useful guidance or reference for predicting longshore sediment transport.

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