• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.257-262
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• 2002

Numerical model introduced in this study combines wave refraction-diffraction, breaking, bottom friction, lateral mixing, and critical shear stress and three sub-models for simulating waves, currents, and bottom change were briefly discussed. Simulations of beach processes and harbor sedimentation were also described at the coast neighboring Bangpo Harbor, Anmyundo, Chungnam, where the area has suffered from accumulation of drifting sand in a small fishing harbor with a wide tidal range. We also made model test for the case of a narrow tidal range at Nakdong river's estuary area to understand the effect of water level variation on the littoral drift. Simulations are conducted in terms of incident wave direction and tidal level. Characteristics of wave transformation, nearshore current, sediment transport, and bottom change are shown and analyzed. We found from the simulation that the tidal level impact to the sediment transport is very important and we should apply the numerical model with different water level to analyze sediment transport mechanism correctly. Although the model study gave reasonable description of beach processes and harbor sedimentation mechanism, it is necessary to collect lots of field observation data, including waves, tides and bottom materials, etc. for better prediction.

• Ocean and Polar Research
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• v.24 no.1
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• pp.39-45
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• 2002

The seasonal patterns of sediment supply were investigated during the period of June 1999 to June 2000 on a coastal foredune of Seungbong Island, Korea. Sediment supply was determined from measurements of geomorphic changes in the foredune and beach along six lines. Most sands were deposited on the dunefoot and foredune area during the winter and spring, from November to April. The largest amount of sands was deposited along the lines 5 and 6 near the sea-dike in the southern tip of the dune area. In general, the sand on the beach was gradually eroded in spring, summer and fall but deposited in winter. Total sediment accumulation over the study period was $484m^3$ for the foredune and $345m^3$ for the beach. The volume of the foredune increased in the winter and spring, whereas the volume of beach increased in the winter. Variation in sediment deposition appears to be controlled primarily by variations in the seasonal wind regime.

• 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 Korea Water Resources Association
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• v.39 no.1 s.162
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• pp.69-77
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• 2006

Songdo beach in Pohang City has suffered from bouts of beach erosion due to various reasons over many years. One of the most controversial issues is the extent of the harbor facilities effect on the beach erosion. In this study, the characteristics of erosion to Songdo beach were reanalysed using historical data and some aerial photos. Specifically, we set test cases based on the history of human modifications to the surrounding area and the topographic change around Songdo beach were investigated by 3D topographical deformation model. In the end, based on the results of these various kinds of investigation, this study found multiple causes of Songdo beach erosion.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.2
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• pp.73-87
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• 2019

Ocean waves are the driving force for the sediment transport and the beach process. However, wave actions are nonlinear and non-stationary, and the response of the beach is inconsistent in terms of reaction rate and magnitude. Therefore, the beach process is difficult to predict accurately. The purpose of this study is to identify the correlations between the shoreline change and ocean waves observed in the east coast of Korea. The relation of the beach width obtained from video monitoring at five sandy beaches and the wave data obtained from nearby wave monitoring at three points was analyzed. Although the correlations estimated over the whole data sets was not significant, the correlations estimated based on the seasonal period or wave conditions provided more noteworthy information. When the non-exceedance probability of the wave height was greater than 0.99, the wave period and beach width showed strong negative correlations. In case the non-exceedance probability of the wave period was greater than 0.99, the wave height and beach width showed strong negative correlations as well. Furthermore, the erosion rate of the beach width increased when the primary wave direction was close to normal to the coastline. Little significant seasonal or monthly change was found between the beach width and the wave, but it was greatly affected by intensive events such as typhoons. Thus, it is necessary to analyze in detail the wave height or period level explaining the change of beach width for more relevant and practical information.

• Journal of the Korean Geographical Society
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• v.48 no.3
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• pp.321-335
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• 2013

High resolution data for the coastal sand beach during short-term in Jinbok-ri, Uljin-gun, Gyeongsangbuk-do are obtained by terrestrial LiDAR. The micro-geomorphological changes of 8 times before and after the strong low-pressure events during June to September, 2009 and changes under the various environments of wave-energy are investigated in the study. The obvious geomorphological changes between the northern and southern sand beach in Jinbok-ri are revealed by terrestrial LiDAR as well as by grain size analysis. The strong waves by the typhoons decrease the area and volume of the beach, and especially the area is largely influenced. The erosive and depositional processes dominate the northern and southern sand beach, respectively, after high wave in September. These results suggest that lots of sand grains in the beach are largely re-transported within the beach rather than offshore.

• Journal of Ocean Engineering and Technology
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• v.27 no.4
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• pp.14-21
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• 2013

This study examined the field application of a 3-D numerical model (LES-WASS-3D) to the estimation of the nearshore current at Songdo beach, Busan. The wave and tide conditions observed at Songdo beach during Typhoon Ewiniar (July 10, 2006) were used in a numerical simulation. The numerical wave heights were in good agreement with the field data. The spatial distributions of the wave heights, mean water levels, and mean flows obtained from the numerical simulation are discussed in relation to the bottom topographical change near Songdo beach before and after Typhoon Ewiniar. The results revealed that LES-WASS-3D is a powerful tool for estimating the nearshore current in the field.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.13-19
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• 2009

The Gwangalli Beach, one of beaches representative of Busan together with the Haeundae Beach, is a tourist attraction, having increased tourists since the completion of Gwangandaero Bridge in 2003 and recording more than 10 million tourists in 2006. Although the competent local government office has conducted artificial beach nourishment/gravel removal projects every year to manage it, systematic monitoring and studies of erosion are insufficient. This study analyzed the changes in the coastline of Gwangalli Beach using aerial photos, tidal data, GPS survey data for the last sixty years, and examined how the Gwangandaero Bridge, which had been constructed on the Gwanganlli sea, has affected the changes. The results show that the area of Gwangalli Beach has increased 40% for the last sixty years, and that the effects of Gwangandaero Bridge on the coastline are insignificant.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.1
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• pp.59-65
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• 2003

The changes of beach profile with a natural longshore bar and beach profile with a fixed artificial bar are studied, respectively, using a numerical model. The quasi three dimensional wave-current-sediment transport model is applied with an addition of boundary condition for sediment transport on the artificial structure under water. The study shows that the natural bar adapts itself to the change of coastal physical environment by adjusting its location but the fixed artificial bar causes the formation of a second natural bar seaward of the fixed bar and scouring at the rear of the fixed bar. This study can be applied to work on the change of beach profile with submerged breakwaters.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.101-115
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• 2006

As coastal erosion is increasing sharply because of sudden changes in the natural environment and increases in artificial development, the problem of coastal erosion become an important issue, socially and economically. To building the data which needed to grasp the situation and find a solution, we need the monitoring system for long-term. In this study, we analyzed the coastal topography and land cover changes in the Haeundae Beach during 60 years. The Haeundae Beach is the most famous beach in the country and coastal erosion are going on. First, we analyzed the change of coastal topography by calculated the coastline and area of the beach using aerial photos during 60 years. We extracted the coastline by digitized on aerial photo and corrected the height of tide level using sounding and GPS survey data. And we computed the area of beach and analyzed the change of area during 60 years. Second, we analyzed the change of land cover using landcover map. We made the detailed landcover map by on-screen digitizing and estimated the soil loss for the area nearby Haeundae Beach. As a result, we could see that the coastline get nearer to land and the area of beach has been reduced in general. We think that interception of sand supply by the development is the artificial cause of coastal erosion. The result of this study would be useful in long-term coastal monitoring and to analyze the cause of coastal environment change. We expect that the result is available on the coastal information system.