• Journal of Digital Convergence
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• v.15 no.3
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• pp.211-219
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• 2017

Among government projects for reduction of coastal disaster, coastal maintenance project stage 1(2000~2009) and stage 2(2010~2019) to reduce coastal erosion and sedimentation are currently under process. In performing the coastal maintenance projects, it is necessary to install artificial concrete armor units for coastal protection. Presently in Korea, products manufactured in Japan are applied to the site, or blocks self-developed by the construction firms are installed. However, there is a lack of technical reviews such as verification of hydraulic characteristics, securing the stability and design techniques. This study is intended to develop waterfront shore protection blocks with good accessibility of people and excellent coastal disaster reduction and protection capability. Through this study, hydraulic characteristics and stability coefficients of shore protection blocks could be drawn.

• Journal of Forest and Environmental Science
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• v.35 no.2
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• pp.78-89
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• 2019

Coastal plantation is one of the key natural defence against the tidal surge induced tropical cyclones. In Bangladesh, a total of 81 km long coastal belt was established from Potenga to Muhuri in Chittagong. This study explores the wind protection efficiency of the coastal plantations at 28 observation points along the 81 km long Potenga-Muhuri irrigation project of Chittagong coastal belt. We found that wind protection efficiency was lowest (1.40% and 7.00%) at $1^{st}$ observation point of outside the embankment (OE) and inside of the embankment (IE) than Sea Shore (SS), respectively. On the other hand, the highest (82.89% and 95.72%) wind protection efficiency was observed at $22^{th}$ observation for Outside of the Embankment (OE) and Inside of the Embankment (IE) than Sea Shore (SS), respectively. This study also highlighted on species specific wind protection efficiency. The result revealed that 6-year old Casuarina, 6-year old mixed plantation and 10-year old Sonneretia apetala with the width of 20.12 m, 30.48 m, and 15.24 m can reduce wind speed up to 30 H, 30 H and 25 H at windward side, respectively. Analysis also showed that percentage of wind reduction was significantly higher at plantation coast than barren, and ship breaking yard coast. The findings of this study have great potentiality to contribute substantially to take more coastal embankment afforestation programs by the Government of Bangladesh and to choose the more wind resistant plant species throughout the coastal areas of the country.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1993.07a
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• pp.38-41
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• 1993

본 모형은 미 공병단에서 개발한 Automated Coastal Engineering System(ACES)중에 포함되어 있는 것으로 바람자료로 부터 파랑을 손쉽게 추정하기 위한 것이다. 바람에 의한 파랑발달과정은 그 기구가 매우 복잡하여 아직도 그 일부만이 밝혀진 상해이다. 바람에 의한 파랑의 발생기구에 대한 연구와 이들 연구를 바탕으로 개발된 수치모형에 대해서는 Shore Protection Manual(SPM)(1984)에 잘 정리되어 있다. (중략)

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.983-993
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• 2008

In recent times, sea level increasing caused by abnormal weather and global warming, sea-sand dredging and complex development causes various kind of erosion damages onto the coastal area in the world. The various types of erosion control and protection methods are applied but there are no signs of fruitful effectiveness. The PC concrete protection block for shore protection structure is practically installed in globally but most of structures in the present day became villainous because of bad accessability. In this study, hydrophilic revetments for control and protection of coastline erosion will be developed in order to make up for a faculty of the shore erosion protection block with better accessibility and excellent protection ability. Experimental measurements were researched to insure for the capacity and facility on reflection coefficient, overtopping volume, and overtopping height characteristics of newly developed shore erosion protection block in model tests. As the result, hydraulic model tests show much excellent than the general step block. Field tests were carried out also to verify through vegetative test on an affinity and construction work test of control-protection on coastline erosion with actual utilization. In the latter case, deposition of sand accumulation occurred in fairly short time at the established reaches and then we can be confirmed to utilize for newly developed block as the revetments for control and protection of coastline erosion.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.537-545
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• 2005

Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bemuse of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, mused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of development such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.11-19
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• 2005

Traditionally Jeju island has a mild oceanic climate throughout the year and famous as worldwide resort area bacause of its pure natural environment and dramatic coastal scenery. But unpredicted coastal erosion problem, caused by variation of environmental conditions from construction of coastal structure and renovation of the existing ports, has raised its head above the water, and is becoming serious these days just like other coastal area in Korea. The phenomena happen here along the seaside of southern part of the island show that severe changes in coastal line from erosion and even witnessed the coastal cliff failure. In advanced countries, coastal engineers and researchers have studied deeply about this kind of problem for a long time. However, as it is not sot active in Korea and lack of research data, there exists difficulties on building protection methods and thoughtless constructions might make it more complicated and fatal to the coastal environment. In this study, we investigated some case studies of other countries and intended to induce and propose some integral protection methods for coastline erosion, considering environmentally sound and water friendly way of developement such as artificial reef, floating breakwater, and double cellblock breakwater. Finally, we made analysis on the proposed methods with numerical model test and evaluation on the feasibility of each method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.342-354
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• 2008

Some statistical characteristics of deepwater waves along the Korean coast have been investigated using various sources of wave measurement and hindcasting data. For very large waves comparable to design waves, it is recommended to use the average value of the empirical formulas proposed by Shore Protection Manual in 1977 and by Goda in 2003 for the relation between significant wave height and period. The standard deviation of significant wave periods non-dimensionalized with respect to the mean value for a certain significant wave height varies between 0.04 and 0.21 with a typical value of 0.1 depending upon different regions and different ranges of significant wave heights. The mean and standard deviation of the principal deepwater wave direction are presented at the 106 coastal grid points along the Korean coast. For relatively large waves, the probability density function of the directional spreading parameter $s_{max}$ is expressed as a lognormal distribution. The most suitable frequency spectrum in the Korean coast is the TMA spectrum. The probability density function of the peak enhancement factor $\gamma$ is also expressed as a lognormal distribution, with its mean value of 2.94, which is close to the value in the North Sea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.292-303
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• 2011

A new type of sand bypassing system is proposed for recovering the eroded beach in this study. This system provides an added methodology to the soft defence which is main recovery method for the coastal shore protection in the world. The study proposes a conceptional design and manufacturing procedure for the relatively small size machine of sand bypassing. In order to get the discharging volume information, the power capacity of the system is tested in the field. The discharge rate of the new system shows up to the expected maximum of 618 ton/hr which is 9.6% lower than that by theoretical calculation. It gives a resonable agreement in this system when the flow is assumed to be of the high density. In this study, the delivering volume of sand is estimated according to the discharge rate. The combination of 300 mm(12 inch) intake and 250 mm(10 inch) discharge pipe line has the pumping capacity of $103\;m^3/hr$ which is nearly the same as that of South Lake Worth Inlet sand bypassing system, Florida, U.S.A.. The proposed system added the mobility to its merit. The unit price of Florida's sand bypassing is $$8~9/m^3$ (US). The system would be economically suitable for small volume of sand because no additional equipment is necessary for the intake. The diesel fuel of 25~30 l/hr was consumed during the system operation. The multiple working system would be the next investigation target for large volume of sand.

• The Journal of Fisheries Business Administration
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• v.29 no.2
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• pp.177-197
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• 1998

Korean fisheries industry is surrounding by domestic and international difficulties due to the effectuation of the UN Convention on the Law of the Sea and declaration by many coastal states of 200-mile Exclusive Economic Zone and acceleration of ocean pollution in global recognition increasing of the importance of the ocean Resource enhancement policy in Korea fisheries industry is very important strategy fer the fostering of the fisheries resource and proper conservation and management of the coastal and off-shore living marine. Among resource enhancement policy, artificial reefs project has been the most effective strategy. The objectives of this paper are to find the economic effects of artificial reefs. The sampling artificial reefs is constructed at Suiido with 6~7m height. In order to analyze the fishing effect of artificial reefs, a few research have been conducted since 1975. For these analysis focuses on the side of scientific effect of artificial reefs, we analyzed on the side of economic effect. The results of the economic effects of artificial reefs are as follows ; First, the fishing effect analysis by using the NPV method in artificial reefs of Suiido ground prove to be economic feasibility. Second, the major socio-economic effect from artificial reefs include the increasing of recreation fishing, maintenance of fishing community, protection illegal fishing, conservation of coastal environment, and enlargement of advanced fisheries supply. Based on the above results, we conclude that artificial reefs project not only contributes to the welfare of fishermen by increasing of economic income, but enlarges to socio-economic gains by protection of illegal fishing and conservation coastal environment and so on.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.25-33
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• 2008

Water waves are generated mainly by winds in open seas and large lakes. They carry a significant amount of energy from winds into near-shore region. Thereby they significantly contribute to the regional hydrodynamics and transport process, producing strong physical, geological and environmental impact on coastal environment and on human activities in the coastal area. Furthermore an accurate prediction of the hydrodynamic effects due to wave interaction with offshore structures is a necessary requirement in the design, protection and operation of such structures. In the present paper surface and internal waves scattering by thin surface-piercing and bottom-standing vertical barriers in a two-layer fluid is analyzed in two-dimensions within the context of linearized theory of water waves. The reflection coefficients for surface and internal waves are computed and analyzed in various cases. It is found that wave reflection is strongly dependent on the interface location and the fluid density ratio apart from the barrier geometry.