scholarly journals Spatiotemporal Variability of Longshore Sediment Transport on the Brazilian Coast

2020 ◽  
Author(s):  
Thaisa Beloti Trombetta ◽  
Wiliam Correa Marques
Keyword(s):  
Sediment Transport ◽  
Southern Region ◽  
Spatiotemporal Variability ◽  
Environmental Damage ◽  
Brazilian Coast ◽  
Study Region ◽  
Longshore Sediment Transport ◽  
Annual Means ◽  
Source Of Information

Abstract The lack of planning and management regarding the transport of sediments along the coast can alter the existing equilibrium in coastal regions, causing or accelerating erosive processes and resulting in economic and environmental damage. Thus, it is important that the characteristics of the coastal drift be investigated, serving as source of information for future projects involving the coastal environment management. Within this context, the present work aims to identify the annual sediment transport averages along the Brazilian coast, the dominant direction of the coastal drift and its spatial variability. For this, a wind-generated wave modeling was considered, with 37 years of data (1979 to 2015), as well as four sediment transport formulations. For the spatiotemporal variability, the analysis of wavelets was applied, relating the effect of cycles of variability over the behavior of longshore sediment transport. The results showed that the largest annual volumes of sediment transport occurred in the northeastern Region of Brazil, reaching approximately 850000 m3/year-1. On the other hand, the smallest transport averages occurred in the southern region, in the state of Santa Catarina, reaching the value of 13497 m3/year-1. In the northeast region, annual and interannual cycles were more frequent and more energetic than in the southern Region, where short cycles presented similar importance to longer cycles, during 37 years of the study. However, in the overall context of the analysis, the long period cycles are more significant for longshore sediment transport, since this is a long term process. In this way, the present article contributes with information on longshore sediment transport, highlighting the annual means and the dominant drift, and deals with important questions about the influence of cycles of variability in the study region, emphasizing the importance of longer period events for the control of sedimentary transport in the Brazilian coast.

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 Assessment of Precipitation Variability and Trends Based on Satellite Estimations for a Heterogeneous Colombian Region

Hydrology ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 128
Author(s):  
Enrique Morales-Acuña ◽  
Jean R. Linero-Cueto ◽  
Fausto A. Canales
Keyword(s):  
Sierra Nevada ◽  
Rainfall Variability ◽  
Spatiotemporal Variability ◽  
Monthly Precipitation ◽  
Study Region ◽  
Resources Management ◽  
Heterogeneous Region ◽  
Average Monthly Precipitation

Adequate water resources management includes understanding patterns and spatiotemporal variability of precipitation, as this variable is determinant for ecosystems’ stability, food security, and most human activities. Based on satellite estimations validated through ground measurements from 59 meteorological stations, the objective of this study is to evaluate the long-term spatiotemporal variability and trends of the average monthly precipitation in the Magdalena Department, Colombia, for the 1981–2018 period. This heterogeneous region comprises many different ecoregions in its 23,188 km2 area. The analysis of spatial variability allowed for the determination of four different subregions based on the differences in the average values of precipitation and the degree of rainfall variability. The trend analysis indicates that the current rainfall patterns contradict previous estimates of a progressive decrease in annual averages due to climate change in the study region, as most of the department does not exhibit statistically significant trends, except for the Sierra Nevada de Santa Marta area, where this study found reductions between 10 mm yr−1 and 30 mm yr−1. The findings of this study also suggest the existence of some links between precipitation patterns with regional phenomena of climate variability and solar activity.

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 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.

Long-term variation of longshore sediment transport

1987 ◽  
Vol 11 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Xie Shi-Leng ◽  
Liu Teh-Fu
Keyword(s):  
Sediment Transport ◽  
Longshore Sediment Transport ◽  
Term Variation

scholarly journals LONGHORE SEDIMENT TRANSPORT ASSESSMENT BASED ON WAVE SYSTEMS

2020 ◽  
pp. 43
Author(s):  
Rodrigo Alonso ◽  
Sebastian Solari
Keyword(s):  
Sediment Transport ◽  
Coastal Management ◽  
Atlantic Coast ◽  
Wave Climate ◽  
Comprehensive Assessment ◽  
Coastal Morphology ◽  
Factors Influencing ◽  
Longshore Sediment Transport ◽  
Main Factors

Longshore sediment transport (LST) is one of the main factors influencing coastal morphology and its comprehensive assessment constitutes a valuable input for coastal management. In this work, the concept of long-term wave systems is used to analyze the wave climate of the Uruguayan Atlantic coast with focus on its impact on LST. It is shown how LST rate estimation changes by consider wave spectral partitions, identifies which wave systems contributes most to LST and provides a more detailed insight on its intra- and inter- annual variability and its correlation with climatic indexes.Recorded Presentation from the vICCE (YouTube Link):

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 Sand spit morphological evolution at tidal inlets by using satellite images analysis: Two case studies in Vietnam

2020 ◽  
Vol 14 (2) ◽  
pp. 17-27
Author(s):  
Nguyen Quang Duc Anh ◽  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Nguyen Trung Viet
Keyword(s):  
Sediment Transport ◽  
Satellite Images ◽  
Morphological Changes ◽  
Morphological Evolution ◽  
Google Earth ◽  
Sluice Gate ◽  
Landsat Images ◽  
Longshore Sediment Transport ◽  
Sand Spit

This paper presents the long-term morphological changes of the sand spits at the Ken Inlet in Ha Tinh Province and Phan Inlet in Binh Thuan Province, Vietnam. The analysis results show that the sand spit morphology at Ken Inlet was drastically changed before the completion of the Da Bac sluice gate construction in 1992, after that the sand spit elongation rate became stable at a rate of about 68 meters per year. Meanwhile, the sand spit at Phan Inlet was breached three times during the winter months of 1990-1991, 1998-1999 and 2014-2015. Moreover, the results of remote sensing image analysis also show that after the sand spit have been breached, it continued elongating at a relatively stable rate of 170÷200 meters per year. Based on the analytical model by Kraus (1999) for predicting the sand spit elongation, the estimated long-shore sediment transport rates of Phan Inlet and Ken Inlet are 145,000 m3/year and 133,500 m3/year, respectively. These longshore sediment transport rates are a main contribution for the sand spit elongation in these study areas. Keywords: sand spits; tidal Inlet; breaching; elongation; Landsat images; Google Earth images.

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