scholarly journals ANALISIS ABRASI DAN AKRESI PERAIRAN PANTAI BARUS TAPANULI TENGAH DENGAN MODEL CEDAS 2.0

2021 ◽  
Vol 17 (2) ◽  
pp. 104-124
Author(s):  
Novi Andhi Setyo Purwono
Keyword(s):  
Sediment Transport ◽  
Shoreline Change ◽  
Forecast Model ◽  
Sediment Supply ◽  
East Side ◽  
Flat Area ◽  
The People ◽  
Building Area ◽  
Western Side ◽  
The Stability

Barus is an area where most of the people are fishermen, this is because Barus is an area located on the coast. The existing condition shows the shoreline on the east side of the seawall building, the condition of the shoreline is experiencing abrasion resulting in the retreat of the coastline and almost reaches the fisherman's flat building area, this is due to the port building in the form of a massive trester jutting into the sea resulting in sediment supply to the retained flat towers and the coastline has declined.To maintain the stability of the coastline, it is necessary to make an effort to control the damage to water in this area. The shoreline model is a numerical forecast model based on the sediment continuity equation and the sediment transport rate equation along the coast. Sediment transport rates along the coast are a function of the variation in height and direction of waves along the coast formed by the effects of refraction and diffraction. The results of the shoreline change model with the protection of the fisherman's flat area from waves by building sea walls is the east side of the fisherman's towers abrasion ± 7 m and sedimentation ± 5 m, the front area of the fisherman's towers does not occur sedimentation or abrasion, the western side of the fisherman's towers does not sedimentation and abrasion occurred, the east side of Barus Jetty did not occur abrasion or sedimentation, the area of Barus Jetty occurred ± 20 m sedimentation, and the west side of Barus Jetty occurred sedimentation ± 9 m. These results indicate that for handling conditions by making a seawall in front of the flat area shows that the location is safe from scouring of waves

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.

scholarly journals Prediction of Shoreline Change for the Calculation of the Integrated Littoral Sediment Budget

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 232
Author(s):  
Yeon-Joong Kim ◽  
Jong-Sung Yoon
Keyword(s):  
Sediment Transport ◽  
Coastal Erosion ◽  
Evaluation System ◽  
Shoreline Change ◽  
Sediment Budget ◽  
Prediction Performance ◽  
Sediment Supply ◽  
Sediment Runoff ◽  
Observation Data ◽  
Sediment Volume

The severe coastal erosions are being accelerated along the east coast of South Korea owing to the intermittent erosions and depositions caused by the imbalance between the effective sediment volume supplied from coasts and rivers and the sediment transport rate. Consequently, many studies are being conducted to develop coastal-erosion reduction measures. To accurately determine the cause of coastal erosion, the causes of the erosion and deposition should be accurately diagnosed, and a comprehensive evaluation system for the sediment transport mechanism in the watershed and sea while considering regional characteristics is required. In particular, realizing the evaluation of the effective sediment volume that flows from the river to the sea through observations is a highly challenging task, and various research and developments are required to realize it, as it is still in the basic research stage. The purpose of this study was to systematically analyze the comprehensive sediment budget for coastal areas. First, an analytical system was developed. Then, a shoreline model was constructed by considering the size of the mixed particles. The parameters required for developing the model were determined using the observation data to improve the shoreline model. A sediment runoff model was applied to evaluate the effective sediment volume supplied from the river to the sea, and the applicability of this model was evaluated by comparing it with the sediment supply volume according to the soil and water assessment tool model. The representative wave and the input parameters of the model were set using the observation data of several years. It was found that the prediction performance of the shoreline change model improved when the effective sediment volume was considered, and the particles of the sediment on the shore were assumed to comprise multiple sizes. In particular, the prediction performance improved when the balance of the sediment budget was adjusted by applying a groin having a structurally similar performance to take into consideration the geographic features of the Deokbongsan (island) in front of the river mouth bar. The model demonstrated a good performance in reproducing long-term shoreline changes when the characteristics of the sea waves and the effective sediment volume were considered.

Shoreline Change Analysis along the Udupi-Dakshina Kannada Coastal Stretch in Karnataka, West Coast of India using DSAS

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
N.A. Anjita ◽  
G.S. Dwarakish
Keyword(s):  
Remote Sensing ◽  
West Coast ◽  
Shoreline Change ◽  
Sediment Supply ◽  
Shoreline Changes ◽  
West Coast Of India ◽  
Erosion Rates ◽  
Wide Range ◽  
Cyclic Changes ◽  
Accretion And Erosion

Study of morphological variations and the effects of oceanographic processes such as erosion and accretion at different temporal scales are important to understand the nature of the coast and the cyclic changes occurring during different seasons. The Udupi-Dakshina Kannada coast along the west coast of India exhibits a wide range of changes depending on the interactions of tide and wave energy, sediment supply and more importantly human intervention. In view of this, the present work has been carried out to study the changes in shoreline changes along the Udupi-Dakshina Kannada coast over a period of 29 years from 1990 to 2019. Remote Sensing and GIS techniques have been used to demarcate shorelines and calculate the shoreline change rates. Overall accretion and erosion rates were found to be 1.28 m/year and 0.91 m/year respectively along the coast. Highest accretion and erosion rates of 12.57 m/year and 5.34 m/year was noticed along the Dakshina Kannada coast. The study also suggests that multi-dated satellite data along with statistical techniques can be effectively used for prediction of shoreline changes. Keywords: remote sensing, GIS, Dakshina Kannada coast, oceanography, shoreline.

Sediment slugs: large-scale fluctuations in fluvial sediment transport rates and storage volumes

1995 ◽  
Vol 19 (4) ◽  
pp. 500-519 ◽  
Author(s):  
A.P. Nicholas ◽  
P.J. Ashworth ◽  
M.J. Kirkby ◽  
M.G. Macklin ◽  
T. Murray
Keyword(s):  
Sediment Transport ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Event Scale ◽  
Fluvial Sediment ◽  
Sediment Routing ◽  
Basin Scale ◽  
Wide Range ◽  
And Storage ◽  
Fluvial Sediment Transport

Variations in fluvial sediment transport rates and storage volumes have been described previously as sediment waves or pulses. These features have been identified over a wide range of temporal and spatial scales and have been categorized using existing bedform classifications. Here we describe the factors controlling the generation and propagation of what we term sediment slugs. These can be defined as bodies of clastic material associated with disequilibrium conditions in fluvial systems over time periods above the event scale. Slugs range in magnitude from unit bars (Smith, 1974) up to sedimentary features generated by basin-scale sediment supply disturbances (Trimble, 1981). At lower slug magnitudes, perturbations in sediment transport are generated by local riverbank and/or bed erosion. Larger-scale features result from the occurrence of rare high- magnitude geomorphic events, and the impacts on water and sediment production of tectonics, glaciation, climate change and anthropogenic influences. Simple sediment routing functions are presented which may be used to describe the propagation of sediment slugs in fluvial systems. Attention is drawn to components of the fluvial system where future research is urgently required to improve our quantitative understanding of drainage-basin sediment dynamics.

scholarly journals How deep does sand deposits in the Alentejo basin (Gulf of Cadiz) reach? Evaluating slope stability from bottom-current activities through time

2020 ◽  
Author(s):  
Davide Mencaroni ◽  
Roger Urgeles ◽  
Jonathan Ford ◽  
Jaume Llopart ◽  
Cristina Sànchez Serra ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Sediment Supply ◽  
Excess Pore Pressure ◽  
Bottom Current ◽  
Gulf Of Cadiz ◽  
Strait Of Gibraltar ◽  
Gulf Of Cádiz ◽  
The Stability ◽  
Iberian Margin ◽  
Excess Pore

<p>Contourite deposits are generated by the interplay between deepwater bottom-currents, sediment supply and seafloor topography. The Gulf of Cadiz, in the Southwest Iberian margin, is a famous example of extensive contourite deposition driven by the Mediterranean Outflow Water (MOW), which exits the Strait of Gibraltar, flows northward following the coastline and distributes the sediments coming from the Guadalquivir and Guadiana rivers. The MOW and related contourite deposits affect the stability of the SW Iberian margin in several ways: on one hand it increases the sedimentation rate, favoring the development of excess pore pressure, while on the other hand, by depositing sand it allows pore water pressure to dissipate, potentially increasing the stability of the slope.</p><p>In the Gulf of Cadiz, grain size distribution of contourite deposits is influenced by the seafloor morphology, which splits the MOW in different branches, and by the alternation of glacial and interglacial periods that affected the MOW hydrodynamic regimes. Fine clay packages alternates with clean sand formations according to the capacity of transport of the bottom-current in a specific area. Generally speaking, coarser deposits are found in the areas of higher MOW flow energy, such as in the shallower part of the slope or in the area closer to the Strait of Gibraltar, while at higher water depths the sedimentation shifts to progressively finer grain sizes as the MOW gets weaker. Previous works show that at present-day the MOW flows at a maximum depth of 1400 m, while during glacial periods the bottom-current could have reached higher depths.</p><p>In this study we derived the different maximum depths at which the MOW flowed by analyzing the distribution of sands at different depths along the Alentejo basin slope, in the Northern sector of the Gulf of Cadiz.</p><p>Here we show how changes in sand distribution along slope, within the stratigraphic units deposited between the Neogene and the present day, are driven by glacial – interglacial period alternation that influenced the hydrodynamic regime of the MOW.</p><p>By deriving the depositional history of sand in the Alentejo basin, we are able to correlate directly the influence that climatic cycles had on the MOW activity. Furthermore, by interpreting new multi-channel seismic profiles we have been able to derive a detailed facies characterization of the uppermost part of the Gulf of Cadiz.</p><p>An accurate definition of sand distribution along slope plays an important role in evaluating the stability of the slope itself, e.g. to understand if the sediments may be subjected to excess pore pressure generation. As sand distribution is a direct function of the bottom-current transport capacity, the ultimate goal of this study is to understand how climate variations can affect the stability of submarine slope by depositing contourite-related sand.</p>

scholarly journals Power to the People: An Inverse Role in Nigeria’s Politics and Governance

2016 ◽  
Vol 11 (2) ◽  
pp. 83-102 ◽  
Author(s):  
Kingsley Onyemekara Onyemekara Emecheta
Keyword(s):  
Political Power ◽  
Power Structure ◽  
Potential Effect ◽  
Democratic Citizenship ◽  
Government Officials ◽  
Economic Interests ◽  
The People ◽  
Ruling Elites ◽  
Political Effect ◽  
The Stability

Abstract An attempt to contextualize the political power structure in Nigeria exposes an orientation and practice that directly negates the democratic norm of power belonging to the people. Today, power belongs entirely to government officials who use it to advance the course of their political and economic interests. The people are thus, subjected to the point and path of complete alienation from the demands and benefits of their democratic citizenship. Given the weakness of the rule of law and institutions of check in Nigeria, established statutes and legislation have not been able to stand tall to relevance in dislodging the hegemony of the ruling elites as is evident in our case study-Imo State. This has since 1999, propped up a telling political effect, which also spirals to the arena of development, and quakes the stability of the state, and the nation at large. The paper examines the current domiciliation of political power, its potential effect on the people, and on service delivery in the country. A case is made for recovery of power for the people and reasserting the law as a balancing force and as means of providing check against breach of constitutionally prescribed political power structure and configuration.

One Method of System Analysis Based on Some Parameters in the Underground Chambers and Application

2007 ◽  
Vol 353-358 ◽  
pp. 2517-2520
Author(s):  
Xiao Jing Li ◽  
Wei Shen Zhu ◽  
Wei Min Yang
Keyword(s):  
System Analysis ◽  
Underground Structure ◽  
Forecast Model ◽  
Underground Opening ◽  
Underground Openings ◽  
Monitoring Result ◽  
Modulus Of Deformation ◽  
Structure Scheme ◽  
The Stability

Based on the underground structure scheme of Langyashan hydro-electrical project, lots of elastic-plastic numerical analysis were conducted considering modulus of deformation, layout depth of underground opening, height of main factory premises, coefficient of lateral compressive stress, as the mainly mechanical parameters that influenced the stability analysis of underground openings. The mathematical statistics method was employed to investigate the displacement variation law of key point surrounding house periphery and found the forecast model. Then the forecast model was used to analyze the sensitivity parameters. It was shown that there was a good agreement between theoretic result and monitoring result in situ.

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.

The Neighborhood, the City, and Beyond

Yeshiva Days ◽  
2020 ◽  
pp. 43-78
Author(s):  
Jonathan Boyarin
Keyword(s):  
Jewish Community ◽  
Jewish Population ◽  
Orthodox Jewish ◽  
Jewish Law ◽  
Lower East Side ◽  
East Side ◽  
The People ◽  
Short Biography ◽  
The City

The chapter presents a short biography and the shiur of the Rosh Yeshiva. It introduces the people who came to the Lower East Side, and the people who were born in the area, which created a network of institutions that has been gradually dwindling for decades. The chapter also tackles how Nasanel wound up at Mesivtha Tifereth Jerusalem (MTJ). Unlike some larger yeshivas, especially perhaps those in Israel, there do not seem to be any formal recruiting efforts at MTJ. Other than those who are from the neighborhood, people find their way to MTJ either because of the Rosh Yeshiva's reputation as a leading authority on Orthodox Jewish law, or because, like Nasanel, they have somehow gotten the sense that the place will be right for them. The chapter then takes a look at the lives of Yisroel Ruven in the Lower East Side, Asher Stoler, Rabbi Canto, both regular at the beis medresh, and the Orthodox Jewish community. Ultimately, it illustrates a neighborhood where the Jewish population has been declining for roughly a century, and where buildings to house Jewish institutions have been progressively emptied out.

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