• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.125-134
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• 1989

A wave overtopping rate from a sea dike of various toe depths is formulated based on a weir model in an unidirectional flow. To evaluate the wave overtopping rate from a seadike on an artificial reef by the weir model, a numerical procedure for predicting wave transformations including the effect of forced wave breaking on the reef is constructed. After confirming the applicability of the model by experiments with regular and irregular waves, the effect of artificial reef on wave overtopping is discussed. So-called individual wave analysis method is shown to be applicable to the wave overtopping caused by irregular waves.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.53-61
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• 2017

Seabed settlement and erosion sometimes occurr when a artificial reef is installed in soft seabed. Therefore, this study carried out CBR test and water tank settlement test to investigate settlement behavior of artificial reef according to reinforcement characteristics such as reinforced types and reinforced area. Soil types of ground are sand, silt and clay deposits. Three reinforced types were prepared: unreinforced, geogrid and hybrid bamboo mat(HBM) with different reinforced area. Laboratory test results indicated that reinforced artificial reef improved bearing capacity of ground and reduced settlement as reinforced area increased. Especially, reinforced HBM provided more bearing capacity and less settlement than reinforced geogrid.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.869-872
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• 2006

By this time, various shapes and materials are used in Artificial Reef. A function of Artificial Reef is leading of fishes by adhesion of seaweeds, however, this effect was not enough. In this study, porous concrete containing function materials (protein, carbohydrates, and fat etc.) are investigated to maximize leading effect of fishes. For these, the mechanical characteristics of porous concrete are investigated with void contents and function materials. Also, the diffusion of function materials are compared to suggest the suitable content of functional material.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.4
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• pp.220-225
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• 2007

The succession of marine benthic algae and the restoration of an artificial seaweed forest on a porous type (shaped half saw teeth) artificial reef at Jeju island, Korea was studied. Young thalli of Sargassum horneri and Ecklonia cava were attached to different artificial substrates. In general, the succession on the artificial reefs led from filamentous algae to perennial algae and involved more than 25 species that are useful fishery resources, including E. cava. Coralline algae were dominant on the artificial reefs at the Kangjung site. The maximum algal biomass on the artificial reef in October 2005 was $1,990g/m^2$ at Biyang. In conclusion, a climax community and seaweed forest can be attained one year after the substrate is constructed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.115-126
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• 1990

In the past, seawall and sea dike very higher than sea-water elevation had been constructed mainly to prevent the wave overtopping volume. However, the coastal zone is recently developed for the multipurpose of not only preventing from the coastal disaster but conserving the coastal environment and utilizing the coastal space. In this sense, this paper deals with the artificial reef being able to reduce the overtopping volume. Relations of the overtopping volume to the breaking wave are briefly reviewed theoretically, and fundamental factor affecting it are also obtained experimentally form the artificial reef with the irregular waves, In addition, the numerical simulation is developed to investigate the effects of spectral band width for the overtopping volume. The most effective artificial reef section to reduce the overtopping volume is proposed.

• Journal of Ocean Engineering and Technology
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• v.21 no.5
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• pp.61-67
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• 2007

As part of the government's fishery resource creation policy, fishing ground creation projects have been undertaken in Korea's major seashore fishing spots since the 1970s, where artificial reefs constructed using new materials that make up for the weakness of concrete reefs have been used. In this study, the stability of these artificial reefs when acted upon by external forces, their ability to attract and gather fish, and their economic feasibility were examined. For this purpose, an experimental artificial steel reef was constructed and was installed in an area of the sea. Then the corrosion of the experimental material attached to it was investigated. The efficiency of the artificial steel reef was then verified by examining its functionality, removal, and burying, as well as the speed of insertion of living things into its structure and its ability to attract and gather fish.

• Journal of Ocean Engineering and Technology
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• v.30 no.3
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• pp.169-176
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• 2016

Considering the artificial reef (AR) canyon intervals facilitated by flatly distributed placement models, the wake volumes of 25 AR sets were characterized through the following works. First, twenty-five different canyon intervals were established to investigate how the intervals affect the wake volumes of the AR placement models, each with nine cube-type ARs. Second, the element-based finite-volume method was used to facilitate flow analyses. Third, the so-called wake volume concept was adopted, and finally a reasonable placement interval was found based on the size of the wake volumes and the associated unit propagation indices. From the analysis results, it was found that a maximum wake volume of 25.18 m³ was generated when the longitudinal and transverse intervals were fixed at 6 m and 0 m, respectively. Thus, to magnify the wake volume, it is recommended that artificial reefs be placed at intervals of 6 m (3 times the reef length) in the flow direction, with no intervals in the normal direction, implicitly indicating that an intensively stacked placement model is a better option to efficiently secure a larger wake volume for the cube-type ARs.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.629-636
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• 2015

This study carried out in order to investigate the most basic elements of suitability selection methods for composition of artificial reef. Acquired data by in-situ measurements and satellite remote sensing analysed in applying GIS. To identify the characteristic of marine environment around the West Sea, the South Sea and the East Sea of Korea, physical conditions-seabed sediment and depth, biological conditions-chlorophyll-${\alpha}$, chemical conditions-Sea Surface Temperature(SST) and DO were used. Suitable sites for artificial reef are selected Taean Peninsula, Geoje, Wando, Pohang, Seocheon, etc. From now on, it will be helpful to effectively utilize artificial reef as well as construct synthetic database. It is also expected to use basic data for artificial reef facilities management.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.227-233
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• 2007

The amount of Batillus cornutus captured in Jeju Island was about 2,000 tons/year for three years after 2000. The mean size of B. cornutus by shell height was 7.7 cm in 2001, 7.9 cm in 2002, and 8.1 cm in 2003. Local mean size of B. cornutus by shell height was 8.7 cm in eastern waters, 7.4 cm in western waters, 7.8 cm in southern waters, and 7.7 cm in northern waters of Jeju Island. To investigate the effect of the growth pattern, an experiment was conducted: the samples were tagged and released in southern coastal waters of Jeju Island on 2nd April (a release test) and 29th October (a recapture test) in 2003. The release stations were two sites, natural reef and artificial reef, where their environmental conditions were different from each other. In April, the size of B. cornutus released in the natural reef was 6.2 cm in mean shell height, and 58.9 g in mean shell weight. The size of B. cornutus released in the artificial reef was 6.6 cm in mean shell height, and 65.9 g in mean shell weight. During the release period, most of B. cornutus were not moved much (less than 10 m) from the original release sites. When B. cornutus was recaptured in October after 7 months, the size of B. cornutus released in the natural reef became 7.4 cm in mean shell height, and 89.4 g in mean shell weight. The size of B. cornutus released in the artificial reef became 7.2 cm in mean shell height, and 84.9 g in mean shell weight. This indicates that the growth rate of B. cornutus released in the natural reef was higher than that of B. cornutus in the artificial reef. These differences in the growth of B. cornutus between study sites were ascribed to the abundance of marine algae grazed by immobile B. cornutus. Namely, with relatively high growth rate of B. cornutus in the natural reef, the number of species (23 species) and biomass (26,703.4 g) of algae were more diverse and abundant than those (7 species and 17,018.4 g) of algae in the artificial reef. The growth of B. cornutus in the natural reef was also correlated to high water temperature $(15.5-25.9^{\circ}C)$.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.233-233
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• 2011

This study describes the characteristics of accretion and scour around artificial reefs in Korea. The survey for accretion and scour was made at a dice reef set consisting of 137 dice reefs. The volume of a dice reef unit is 8 $m^3$. The reef set was placed on the muddy sand at 21.6 m in November of 1999. Equipment used in the survey includes Side Scan Sonar, Multi Beam Echo Sounder, Sub-Bottom Profiler and water current meter. According to the results, the artificial reefs are heaped up at two to three times (4 m) the height of the dice reef. The maximum current around the artificial reefs was 81.5 cm/sec at the ebb tide and 72.7 cm/sec at the flood tide. Scour around artificial reefs occurs upstream to the flow while accretion is formed at wake zone in the downstream. The height of accretion ranges from 2.4 to 3.0 m. The crest of the accretion is formed at the distance of about 10 m from the edge of the reef. The slope of accretion is formed steeply at the vicinity of the reef which is at right angles to the direction of main current, and grows gently lower with the increased distance from the reef. Scour is continuously caused by upwelling from the reef set and by side currents that flow parallel to side of the accretion. Also, scour takes place on the deposited sediment rather than on the remaining bottom sediments. This means that, once fully formed, the depth of scour gully on both sides to the direction of main current hardly changes.