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 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 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.

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.

A Feasibility Investigation for Developing Artificial Beachrocks: A Potential Measure for Coastal Protection in Southeast Yogyakarta Coast, Indonesia

2020 ◽  
Author(s):  
Lutfian Rusdi Daryono ◽  
Kazunori Nakashima ◽  
Satoru Kawasaki ◽  
Koichi Suzuki ◽  
Anastasia Dewi Titisari ◽  
...  
Keyword(s):  
Physical And Mechanical Properties ◽  
Sandy Beaches ◽  
Coastal Sediments ◽  
Coastal Protection ◽  
Optimum Conditions ◽  
Short Term ◽  
Resistivity Survey ◽  
Wave Effects ◽  
Potential Measure

<p>Erosion prone sandy beaches are frequently covered by cement and mortar to preserve the coastal zone, but the conventional approach has an adverse impact on the environment, altering the coastal landscape and processes unfavorably. The term “beachrock” refers to cemented coastal sediments through a long-term formation of CaCO<sub>3</sub> cement, and which is an important feature in many tropical coastlines as it appears to have a substantial anchoring effect against wave effects and erodibility. Therefore, the objective of this study is to evaluate the feasibility in progressing the formation of artificial beachrocks using natural materials (e.g., microbes, sand, shell, pieces of coral, and seaweed etc.) within a short-term, and to introduce the method as a novel candidate for coastal protection. In this study, both resistivity survey and multi analysis seismic wave (MASW) survey along the same lines were performed at first to elucidate the subsurface structure of existing beachrocks in the Southeast Yogyakarta coastal area (Indonesia), followed by the laboratory analysis, which is aimed understand the basics in the formation mechanism. Peloidal micrite cement, the cement comprised of aragonite needles, micritized granules and the cover of micritic were observed in natural beachrocks. Mimicking the mechanism, an attempt has been undertaken to develop artificial beachrocks in the laboratory via microbial induced carbonate precipitation (MICP). Finally, the physical and mechanical properties were well compared between the artificially formed beachrocks and natural beachrocks collected from the survey lines. The results suggest that the artificial deposits treated for 14 days under optimum conditions, achieved a peak unconfined compressive strength of around 6 MPa similar to that of weak-consolidated natural beachrock. The comparison further reveals that the variables such as porosity, Vp, Vs, and strength are primarily rely on the precipitated morphology of the crystals.</p>

scholarly journals In Use of Permeable Groin for Reducing Longshore Sediment Transport at Tanjung Bayang Beach of South Sulawesi

2018 ◽  
Vol 1 (2) ◽  
pp. 70-73 ◽  
Author(s):  
Hasdinar Umar ◽  
Sabaruddin Rahman ◽  
Chairul Paotonan ◽  
Ahmad Yasir Baeda
Keyword(s):  
Sediment Transport ◽  
Coastal Protection ◽  
Breaking Wave ◽  
Longshore Current ◽  
Surrounding Area ◽  
South Sulawesi ◽  
Longshore Sediment Transport ◽  
Reduction Coefficient ◽  
Before And After ◽  
Transport Analysis

Breaking wave near beaches is the main force to generate longshore currents, which moved the sediment at surrounding area. Due to its negative outcome, which are erosion and sedimentation, the need of longshore sediment transport analysis become very important. One of the tools for solving that problem is by using coastal protection structure such as permeable groin. Permeable groin may reduce the rate of longshore sediment transport respectively by changing the level of permeability of the groin itself. The objective of this research was to obtain analytical results of the longshore sediment transport reduction analysis by using permeable groins at Tanjung Bayang Beach of South Sulawesi. Reduction of sediment transport along the beach was analyzed by calculating reduction coefficient, which is the ratio between the longshore current before and after hitting the permeable groins. The result showed that with 40% of permeability, the groin can reduced longshore sediment transport at Tanjung Bayang Beach for almost 50%; from 341.37x103 m3/year to 170.68x103 m3/year.

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.

Cross-Shore Sediment Transport for Modeling Long-Term Shoreline Evolution

2021 ◽  
Vol 147 (4) ◽  
Author(s):  
Yan Ding ◽  
Richard Styles ◽  
Sung-Chan Kim ◽  
Rusty L. Permenter ◽  
Ashley E. Frey
Keyword(s):  
Sediment Transport ◽  
Shoreline Evolution

The phoenix of beachrocks: Simultaneous breakdown and formation of an unusual facies on a high energy coastline (Mission Rocks Beach, South Africa)

2020 ◽  
Author(s):  
Michaela Falkenroth ◽  
Andrew N. Green ◽  
J. Andrew G. Cooper ◽  
Gösta Hoffmann
Keyword(s):  
South Africa ◽  
Sea Level ◽  
Anthropogenic Activities ◽  
High Energy ◽  
Coastal Sediments ◽  
Level Indicator ◽  
Shoreline Evolution ◽  
Carbonate Cements ◽  
North Eastern

<p>Beachrocks are coastal sediments that are lithified through the precipitation of carbonate cements. It is widely acknowledged that lithofacies in beachrocks are variable and their interpretation is useful when using beachrock as a sea level indicator or when studying shoreline evolution over the centurial to millennial scales. Surprisingly however, the facies variability of beachrocks remains understudied as they are almost exclusively described as seaward dipping, slab-shaped outcrop forming in low energy dissipative beach environments. The Mission Rocks coastline of north-eastern South Africa is in stark contrast. Here the coast comprises an up to 3 m thick raised shore platform of beachrock, where a variety of sedimentological facies are observed. These comprise seaward-dipping planar bedded sandstones and conglomeratic units, often interbedded with bimodally-orientated trough cross bedded sandstones. In our study we aim to use sedimentological facies analysis, petrography and cathodoluminescence to unravel the deposition- and cementation processes of this beachrock facies.</p><p>In particular, an unusual beachrock breccia interposed amongst the breakdown remnants of the platform forms the basis of this paper. The breccia documents a cycle of simultaneous erosional breakdown and depositional buildup of the beachrock platform, a yet undescribed process for the development of beachrock.  Since it forms as a thin veneer (< 0.10 m), with a slightly thicker infill (≤ 0.5 m) amidst erosional hollows and gullies of the + 2 m high rocky platform, it raises into question the necessity of a thick sedimentary overburden, that is typically considered the requirement for beachrock cementation in the mixing zone.  Timing of beachrock formation is constrained by recent anthropogenic activities, as the underlaying platform was mined for building purposes during WWII and it is in these quarry slots and crack that the beachrock is found. While it is generally suspected that beachrocks may form at the centennial scale, evidence for this remains weak. Not only can the interpretation of this facies contribute to our understanding of the long term processes that form and break down beachrocks on high energetic coastlines, it provides insight into rapid beachrock formation and as such its utility as a sea level index point.</p>

scholarly journals NUMERICAL MODELING OF SHORELINE EVOLUTION AROUND THE RIVER MOUTH

1984 ◽  
Vol 1 (19) ◽  
pp. 202
Author(s):  
Ming-Chung Lin ◽  
Jyh-Cherng Wang
Keyword(s):  
Numerical Models ◽  
River Sediments ◽  
River Mouth ◽  
Typical Feature ◽  
Wave Condition ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Proposed Model ◽  
Wave Induced

The river sediments transport into coastal water together with wave induced longshore sediment transport make shoreline evolution much complicated. Fig.l shows typical feature of shoreline shape around a river mouth. Recently there are some investigators treated this problem (Grijm, 1964, Bakker §Edelmen,1964; Komar,1973; Tsuchiya § Yasuda,1978),and had developed some mathematical or numerical models. This paper proposes a numerical model for predicting long-term shoreline evolution around a river mouth by incorporation certain river parameters into the Willis beach evolution model (1978). The proposed model is at first applied to four ideal cases to investigate its general characteristics and adaptability, and reasonable results are found. In our results the accretion on updrift side is faster than downdrift side under the oblique incident wave condition and the width of the river mouth increase steadily. These results are different from other approachs that the shoreline shape is always nearly symmetrical with respect to the centerline of the river mouth. Finally, as an field case application of the model, a numerical simulation of shoneline changes around the Cho-shui River mouth is performed and compared with field data.

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