• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.246-256
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• 2021

Various development projects occurring on the coast cause an imbalance of surface sediments, causing coastal disasters or irreversible coastal erosion. Coastal erosion caused by the influence of various port structures built through coastal development can be directly identified by evaluating changes in the sediment budget, longshore sediment, and cross-shore sediment. In other words, it will be possible to evaluate the causality between coastal development and coastal erosion by classifying regions due to single cause and regions due to multiple causes according to the changes in the sediment classified into the three types mentioned above. In this study, the cause of long-term and continuous erosion was analyzed based on the analysis results of the coastal development history and the Coastal Erosion Monitoring targeting the coast of Gangwon-do and Gyeongsangbuk-do on the east coast. In addition, in order to evaluate the degree of erosion caused by the construction of artificial coastal structures, the concept of erosion impact assessment was established, three methods were proposed for the impact assessment. The erosion impact of Hajeo port was assessed using the results of satellite image analysis presented in the Coastal Erosion Monitoring Report, it was assessed that the development of Hajeo port had an impact of 93.4% on erosion, and that of the coastal road construction had an impact of 6.6%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.639-650
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• 2022

In areas where large-scale sediment transport occurs, it is important to apply appropriate countermeasure method because the phenomenon tends to accelerate by time duration. Among the various countermeasure methods applied so far, beach nourishment needs to be reviewed as an erosion prevention measure because the erosion pattern is mitigated and environmentally friendly depending on the particle size. In the case of beach nourishment. a detailed review is required to determine the size, range, etc., of an appropriate particle diameter. In this study, we investigated the characteristics of the related topographic change using the change in the particle size of nourishment materials, the application of partial area, and the condition under the coexistence of waves and wind as variables because those factors are hard to be analyzed and interpreted within results and limitation of that the existing numerical models are not able to calculate and result out so that it is required that phenomenon or efforts are reviewed at the same time through physical model experiments, field monitoring and etc. So we attempt to reproduce the tendency of beach erosion and deposition and predict possible phenomena in the future using machine learning techniques for phenomena that it is not able to be interpreted by numerical models. we used the hydraulic experiment results for the training data, and the accuracy of the prediction results according to the change in the training method was simultaneously analyzed. As a result of the study it was found that topographic changes using machine learning tended to be similar to those of previous studies in short-term predictions, but we also found differences in the formation of scour and sandbars.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.661-669
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• 2000

The accurate prediction of wave-induced currents is indispensible to analyze the beach deformation due to the sediment transport or dispersion in the surf zone, which often gives rises to serious environmental problems in the coastal region. Although many numerical models have been suggested up to now, it is not easy to properly simulate wave-induced currents, in particular, over a complex topography. In order to solve these problems, we have to understand the mechanism of wave transformation and wave-induced currents, to compare results numerical models with those of field measurements, and to find the validity and the applicability of them. And, also the validity of the model has been confirmed by the field investigation.

• Water for future
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• v.17 no.3
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• pp.197-209
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• 1984

This study has been carried out to investigate into the local scour of wall-toe and the beach deformation caused by the construction of a seal wall. It has been performed to determine the values of the marine invertigation of HAE UN DAE and two dimensional Movable bed gydraulic model test. From the results of this work approtection method of HAE UN DAE beach erosion is established to reduce the amount of topography deformation by investigating the values of the constructive position of a sea wall, seabed slope, the maximum scour depth, the first and the second influence range, the maximum quantity of beach deformation, and the distance measured from the sea will to the maximum quantity of beach deformation.

• Journal of Environmental Science International
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• v.15 no.9
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• pp.881-886
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• 2006

The purpose of this research is to examine the beach erosion prevention capability of submerged breakwaters under wave energy condition. To accomplish this objective, the computational domain was divided into two do-mains : the large and the detailed domain for the Song-Do beach. For each computational domain, numerical models for calculating transformation, wave induced current and beach erosion were used and also these numerical models were carefully applied to three experimental cases such as 1) the present beach condition, 2) the condition for which submerged breakwaters are installed about 240m from the shoreline of beach enlarged by artificial nourishments. The results of this research show that if storm waves attack the present beach, the erosion occurs widely all over the beach. However, when the submerged breakwaters are installed in addition to the artificial nourishments, storm waves can be adequately controlled and strong wave induced currents occur only around the submerged breakwaters resulting in the beach evolution appearing locally only at the western end of the beach.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.493-499
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• 1997

Grain size analysis have been made for the carbonate-detrital mixed sediments on the continental shelf off the southeastern coast of Korea. The detrital components are well-sorted with mean grain size between 2-3 phi. The detrital components are thought to be deposited in the beach environment during the glacial times when the sea level was low, representing typical 'relict' sediments. Most of the carbonate components consist of shell fragments, and are deeply weathered. They are also interpreted as the relict components that were deposited in the shallow marine environment. The carbonate fraction are coarser-grained and poorly sorted compared to the detrital component. The carbonate components are thought to have experienced the continuous environmental control of fragmentation and selective size sorting after the deposition.

• Journal of Ocean Engineering and Technology
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• v.31 no.1
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• pp.60-68
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• 2017

In this study, we analyzed the real time video image obtained from the video monitoring system to grasp the shoreline, beach width, and area change of Haeundae beach. The video monitoring techniques enabled continuous monitoring for a long period at a much lower cost than general survey methods. It was possible to grasp quantitative beach variation characteristics of Haeundae beach through image acquisition, rectification, and image processing of video images. According to the monitoring results, the erosion rate of Haeundae beach in spring and summer was -19.8% in 2014 and -6.7% in 2015. The erosion rate in 2016 was -6.4%, which showed that the erosion rate in spring and summer continued to decrease. In particular, the influence of the erosion at the time of typhoon CHABA was revealed to be smaller than in the past. It can be concluded that these variations were due to beach width expansion by beach nourishment and the installation of submerged breakwaters.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.2
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• pp.95-100
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• 2010

In this study we predicted some of the negative effects on the ocean ecosystem and water quality, caused by a coastal reclamation project in semi-closed bay that makes it extremely difficult to be purified by natural process. In order to predict change of water quality triggered by coastal reclamation, the 3D hydrodynamic model and material cycle model are used. And we suggested new ecological park, an artificial beach and eco-friendly revetments on the reclamation area to mitigate the environmental impacts affecting this area using the numerical simulation results and observation data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.40-42
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• 2018

지구온난화에 따른 연안의 해수면 상승은 해안에 가해지는 파랑에너지의 상승을 유발한다. 이러한 해수면의 상승은 상대적으로 수심이 깊어지는 효과를 초래하고 이는 과거 발생하지 않았던 해안지역의 침식 및 해빈에서의 모래를 유실시킨다. 특히, 국내 연안 225개소의 연안 모니터링 결과 142개소인 62%가 침식우려 이상의 등급으로 나타났다. 일반적으로 연안침식에 대응하는 방법은 호안을 쌓아 보호하게 되는 경성공법으로 외력의 변화에 따라 현장여건에 맞는 호안의 경사, 단면형상 및 재료를 선택하게 된다. 하지만 현상에 대한 불충분한 이해에 근거한 공법 적용으로 제반국가에서 다양한 피해가 발생하고 있으며, 이는 공법신뢰도 향상을 위한 기술개발 및 융합기술 도입의 필요성을 보여준다. 본 연구는 파랑저감에 효과적인 다공성 구조물Biocoast를 활용하여 해안침식피해억제를 위한 친환경 투수 바이오 콘크리트 블록을 개발하였다. 특히, 자연해변 및 호안시설에 대해 자연 및 인위적 외력에 의한 침식과 세굴로부터 연안을 보호하고, 블록의 유닛화를 통해 품질관리 및 공정관리의 효율성을 향상시킬 수 있을 것으로 사료된다.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.13-24
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• 2002

In a physically realistic but simplified manner, an attempt is made in this study to develop a predictive model for swash hydrodynamics across the shore due to the storm waves on an arbitrary beach profile. Date from the SUPERTANK laboratory Data Collection Project are used for the model development, in which experiments were designed to simulate dune erosion under storm conditions at a prototype scale. The model predicts variations of swash height, velocity and period across the beach face in a swash zone. In general, the model proves to be capable of predicting variations of swash height, velocity and period across the shore. Quantitatively better predictions for the swash parameters could be achieved by improving the prediction of the beach face elevation, ymax, where the significant swash height becomes zero.