• Title/Summary/Keyword: Natural coastal defence

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Geomorphological Characteristics and OSL Ages of the Moraeul dune in Daechoengdo Island, South Korea (대청도 모래울 사구의 지형 특성과 OSL 연대)

  • Choi, Kwang Hee
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.4
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    • pp.1-11
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    • 2020
  • Coastal dunes play an important role in coastal defense. The Moraeul dune in Daecheongdo Island is representative in this regard. However, there is little knowledge, concerning the morphology, grain size, and formation timing of the dune. This study investigated the geomorphological characteristics of the Moraeul dune using topographic surveys, grain size analyses, and OSL dating. The dune was classified as 'single accreted foredune', which was developed under dense vegetation cover and efficient sand trapping. The dune consisted of fine to medium sand with 1.6Φ of mean grain size, and was covered with pine trees (> 100 years old). The samples from the upper part of the dune yielded quartz OSL ages ranging 0.5 ~ 0.7 ka. Therefore, it is likely that the dune developed at least before the Little Ice Age and became what it is today about one century ago.

A Theoretical Review on the Planting and Management of Coastal Forests in Korea (우리나라 해안림조성과 관리의 이론적 고찰)

  • Kim, Yong-Shik;Kim, Do-Gyun
    • Korean Journal of Plant Resources
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    • v.30 no.1
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    • pp.110-123
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    • 2017
  • The authors reviewed the history of creation and management, purposes, extents, methods of creation, planting species and mediums, structure of vegetation layers and legal management, etc. of coastal forests of Korea. Since the Goryeo dynasty, the inhabitants in the coastal regions has long been aware the safety from natural disasters and the local governments manages for the defence and natural disasters, and collaboration among GO and NGOs, as well as enterprises are participating to the conservation of coastal forests in Korea. The purposes of creation and management of coastal forests in historical aspects are prevention of disasters, safety by the Fengsui, military uses, and timber productions, but partly as the places for religious beliefs, safety from diseases and fires, increasing of forest products and fishes, as well as tourists, improving of amenity and landscapes and recreation, inherits of traditional culture, habitats for wildlife, and ecological corridors, etc. The inhabitant in the coastal region who experienced frequent natural disasters has strong supports for the conservation of coastal forest and as a natural resources to inherits to the coming generations as the coastal forests has high values of academic researches on human society, culture, ecology and recreational uses, etc. The extensive overall researches on the creation and managements of coastal forests, as well as cultural tradition in the coastal forests of Korean peninsula are critically essential.

Wind Speed Reduction Efficiency of Potenga-Muhuri Irrigation Project Coastal Belt in Chittagong, Bangladesh

  • Kader, Mohammad Abdul;Hossain, Mohammed Kamal;Kabir, Md. Humayain
    • 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.

Coastal Zone Management in the United States of America (미국의 해안관리 -New Jerseyization의 반성과 연방정부 연안역관리 프로그램의 확산-)

  • Yu, Keun-Bae
    • Journal of the Korean Geographical Society
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    • v.44 no.4
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    • pp.481-496
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    • 2009
  • Every coastal area exhibits its own unique landscape owing to the combination of the natural and cultural processes. Coastal barrier islands well show the cultural aspects of American coastal landscapes. Some 47% of barrier island area was occupied by urban and built-up area in New Jersey, while some 5% in Georgia. Tourism-related development is back to in the mid 19C. in N.J. due to the closeness to heavily populated areas such as New York and Philadelphia. Developments without proper understanding the nature of coastal processes caused New Jerseyization, the destruction of the beauty or naturalness. It was mainly due to the lack of growth-control policies and the foresight for the future coast in the processes of legislation. North Carolina's islands experienced an increase of 269% in urbanized acreage between 1956 and 1976. However, N.C. exercised her wisdom to recover the naturalness of the coastal environs: all engineering structures are banned on the beaches. Nine out of 13 barrier islands in Georgia exist in the wilderness condition owing to her unique history. The remaining islands still experienced the least development. After the Civil War most of Georgian islands were owned by rich families and maintained as wilderness. In the 1970s most of the uninhabited islands were sold or donated to research institutes or governmental agencies.