Sediment transport modeling at Stono Inlet and adjacent beaches, South Carolina

This report documents a numerical modeling investigation for dredged material from nearshore borrow areas and placed on Folly Beach adjacent to Stono Inlet, South Carolina. Historical and newly collected wave and hydrodynamic data around the inlet were assembled and analyzed. The datasets were used to calibrate and validate a coastal wave, hydrodynamic and sediment transport model, the Coastal Modeling System. Sediment transport and morphology changes within and around the immediate vicinity of the Stono Inlet estuarine system, including sand borrow areas and nearshore Folly Beach area, were evaluated. Results of model simulations show that sand removal in the borrow areas increases material backfilling, which is more significant in the nearshore than the offshore borrow areas. In the nearshore Folly Beach area, the dominant flow and sediment transport directions are from the northeast to the southwest. Net sediment gain occurs in the central and southwest sections while net sediment loss occurs in the northeast section of Folly Island. A storm and a 1-year simulation developed for the study produce a similar pattern of morphology changes, and erosion and deposition around the borrow areas and the nearshore Folly Beach area.

Wave transformation around breakwater (case study: tourism harbour, Eastern Bali, Indonesia)

An essential aspect in the sustainable design of breakwater is the determination of the design wave condition. It is predicted by utilizing severe wave conditions of the past 10 to 20 years. The tourism harbor at eastern Bali, Indonesia, is located where extreme wave condition occurs. Therefore, this research studies the wave height before and after constructing a breakwater in the harbor area. The wave height was simulated using numerical modeling. The methodology was performed by using the coastal modeling software of the SMS-CGWAVE model. The result shows the highest design wave height value of 3.9 m in the direction from the southeast. The design breakwater can reduce wave height up to 0.9 m or a 75.5% reduction. Further study is needed to simulate the extension of breakwater length to meet the criterion design of wave height in the harbor basin.

Sediment Transport and Morphological Response to Nearshore Nourishment Projects on Wave-Dominated Coasts

Nearshore nourishments are constructed for shoreline protection from waves, to provide sediment nourishment to the beach profile, and to beneficially use dredged sediment from navigation channel maintenance. However, it is poorly understood how placement morphology and depth influence nearshore processes operated on wave-dominated coasts. This study investigates the wave fields, sediment transport, and morphological response to three common nearshore nourishment shapes, nearshore berm (elongated bar), undulated nearshore berm, and small discrete mounds, with numerical experiments utilizing the Coastal Modeling System. The nourishments are placed in depths between 3 m and 7 m with a volume of approximately 100,000 m3 and between 400 m and 1000 m in alongshore length. Numerical experiments are carried out in three distinct coastal settings with representative wave climates and geomorphology. Simulation results indicate that shallower, more continuous berms attenuate the most wave energy, while deeper, more diffuse placements retain more sediment. Results from this study improve the understanding of nearshore nourishment shapes and can support decision makers identifying the most appropriate construction technique for future nearshore nourishment projects.

Evolution of the Beaches in the Regional Park of Salinas and Arenales of San Pedro del Pinatar (Southeast of Spain) (1899–2019)

Coastal erosion is anissuewhich affects beaches all over the world and that signifies enormous economic and environmental losses. Classed as a slow phenomenon, the evolution of the coastline requires long-term analysis. In this study, old cartography and aerial photographs from various dates have been used to study the evolution of the coastline. The information has been processed with free software (QGIS) and for the calculation of sediment transport the Coastal Modeling System (SMC) software. The results show the accretion/erosion phenomena that occurred after the construction of the port in San Pedro del Pinatarin 1954 and which changed the coastal dynamics of a highly protected area. In some sectors, the beach has been reduced almost in its entirety, with retreat rates of up to −2.05 m per year and a total area loss of 66,419.81 m2 in Las Salinas beach and 76,891.13 m2 on Barraca Quemada beach.

Development of a global sediment dynamics model

Sediment dynamics play an important role in various aspects of earth system modeling. In this study, we developed a global sediment dynamics model that considers suspended sediment and bedload at short timescales. We validated suspended sediment from four observation stations in the Amazon River basin and over 60 observation stations from around the world based on a variable criteria such as availability of data samples. Our model was able to effectively reproduce seasonality and spatial distribution of suspended sediment flow. However, our global estimate of approximately 4 Bt/a was significantly lower than previous estimates; therefore, we discuss potential causes of this discrepancy, including target time period and discrepancies with previous extrapolated methods. Our newly developed sediment dynamics model could provide a better understanding of global sediment transfer and contributes to various related research fields such as coastal modeling and natural disasters.

AVALIAÇÃO DA QUALIDADE DA BASE DE DADOS DE ONDAS DO SISTEMA DE MODELAGEM COSTEIRA – BRASIL PARA A COSTA LESTE DO BRASIL (EVALUATION OF QUALITY OF THE WAVE DATABASE OF THE COASTAL MODELING SYSTEM – BRAZIL TO THE EASTERN COAST OF BRAZIL)

RESUMO:O propósito do presente trabalho foi avaliar a qualidade do banco de dados de ondas do programa SMC – BRASIL, sobretudo quanto à existência no mesmo de ondas de NE, em um trecho da costa leste brasileira. Para isso, foram realizadas modelagens em regiões cujos indicadores geomorfológicos indicassem deriva litorânea para os quadrantes SE e SO, que teoricamente seriam causadas por estas ondas, nos municípios de Ilhéus/BA, Prado/BA e Itaúnas/ES. No banco de dados do SMC, foram identificadas ondas de NE apenas em Prado (0,01%). Ondas de ENE foram identificadas em Prado (3,01%), Ilhéus (0,02%) e Itaúnas (0,02%). Em todos os casos, as ocorrências foram em quantidade bem menor do que as registradas em estatísticas de ondas e na literatura. O transporte litorâneo modelado para as três áreas direcionou-se para N, NE e NO, de forma contrária ao esperado pela configuração dos pontais arenosos presentes. As correntes costeiras modeladas para ondas de NE e de ENE direcionam-se para os quadrantes SE e SO, o que demonstra que as correntes geradas pelo programa são coerentes; e que o problema do programa é a pequena quantidade dessas ondas presentes em seu banco de dados, o que afeta o resultado do transporte litorâneo resultante.Palavras Chave: SMC; Deriva Litorânea; Regime de Ondas, Costa Leste do Brasil. ABSTRACT:The purpose of the present work was to evaluate the quality of the wave database of the SMC - BRASIL program, especially regarding the existence of NE waves in a stretch of the Brazilian eastern coast. For this, modeling was performed in regions whose geomorphological indicators indicated coastal drift to the SE and SO quadrants, which theoretically would be caused by these waves, in the municipalities of Ilhéus / BA, Prado / BA, and Itaúnas / ES. In the SMC database, NE waves were only identified in Prado (0.01%). ENE waves were identified in Prado (3.01%), Ilhéus (0.02%) and Itaúnas (0.02%). In all cases, the occurrences were much smaller than those recorded in wave statistics and in the literature. The coastal transport modeled for the three areas was directed to N, NE and NO, in a way contrary to the one expected by the configuration of the sand spits present. Coastal currents modeled for NE and ENE waves are directed to the SE and SO quadrants, which demonstrates that the currents generated by the program are coherent; and that the program problem is the small amount of these waves present in your database, which affects the result of the efective coastal transport.Keywords: SMC. Littoral Drift; Wave Regime; East Coast of Brazil.