• Title/Summary/Keyword: reclamation of tidal land

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Estimation of morphological change using waterline method in the Ganghwado tidal flats

  • Lee, Yoon-Kyung;Ryu, Joo-Hyung;Eom, Jin-Ah;Jo, Min-Jeong
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.22-24
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    • 2007
  • Waterline extraction is the one of widely used methods for studying changes in tidal flat environment and coastlines using multi-temporal optical images such as Landsat TM and Landsat ETM+. High dynamics of tidal currents and land reclamation which accelerate sedimentation and/or erosion cause waterline change in tidal flats. The amount of sediment deposited or eroded can be evaluated by precisely estimating waterline changes in tidal flats. The objective of this study is to detect the change of waterlines during 17 years and analyze the trends of erosion and sedimentation in the study areas. The Ganghwado tidal flat on the west coast of the Korean Peninsula was selected. The study area is famous for high dynamics of tidal currents and vast tidal flats. Land reclamation which has been carried out on a large scale is also considered as one of elements that have accelerated the environmental changes in this tidal flat. In this study, we acquired 26 waterlines from Landsat TM and Landsat ETM+ images. We extracted the waterline from each satellite image to generate a digital elevation map (DEM) which was used for reference and to compare with the other waterline which was extracted from DEM having a same tide. The result of comparison well depicted the areas of dominant sedimentation and erosion, and general trends of sedimentation and erosion according to sub-regions are also revealed during the investigation time. Results showed that erosion during a decade was dominant at the west of the Southern Ganghwado tidal flat, while sedimentation was dominant at the wide channel between the Southern Ganghwado tidal flat and the Yeongjongdo tidal flat. This area has been commonly affected by high currents and sedimentation energy. Although we were not able to verify the accuracy of the waterline changes, this result clearly showed the waterline change and therefore, the waterline extraction method used in this study has proven as an effective tool for long term tidal change estimation.

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A study of seasonal variation of the residual flow before and after Saemangeum reclamation (새만금간척전 .후 잔차류의 계절변화에 관한 연구)

  • 신문섭
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.155-161
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    • 1999
  • The land reclamation area of Saemangeum(Kunsan) is located between 126$^{\circ}$10' E~126$^{\circ}$50' E and 35$^{\circ}$35' N~356$^{\circ}$05'N at the western coast of the Korean peninsula. The are many small islands including extensive areas of semi-diurnally flooded and dewatered tidal flats. The reclamation area of Saemangeum has a range of 5.6m spring tide and the maximum tidal current speed is about 1.41m s-1 in ordinary spring tide. Most of the sediments deposited on the tidal flats are transported from the Geum river, the Manjyung river and The Dongjin river. The soil in this area consists of silty sand with the depth of 10m to 30m . The wind in winter is strong from the direction of northwest. In the past twenty years, land reclamation projects for agricutural purpose or industrial cocmplex have been mostly implemented along the western coast of Korea. Saemangeum coastal area is being constructed the33km sea dike and 40, 100ha reclamation area. The purpose of this study is to find the residual circulations in four seasons after the dike construction by a robust diagnostic and prognostic numerical model. Heat flux at the sea surface in January ,May , August , October was asopted on the basis on the daily inflow of solar radiation at the earth surface, assuming an average atomospheric transmission and no clouds , as a function of latitude and time of year(George L.P.J.E William, 1990). The discharge from the Geum , the Mankyung and the Dongjin rivers was adopted on the basis of experience formula of river flow in January , May ,August, October (The M. of C.Korea, 1993) . Water temperature and salinity along the open boundaries are obtained from the results of field observation s.

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Estimation of Areal Change in Hwa-ong Tidal Flat due to Sea Dike Construction Project using Multi-temporal Landsat TM Images (다중시기 Landsat TM 영상을 이용한 화옹지구의 간척사업에 따른 갯벌면적의 변화 추정)

  • Kim Seong-Joon;Bang Ro-Sung;Kwon Hyung-Joong
    • KCID journal
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    • v.10 no.1
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    • pp.73-79
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    • 2003
  • The purpose of this study is to suggest a simple estimation method of tidal flat areas using multi-temporal Landsat TM images due to the progress of sea dike construction for tidal land reclamation. As a case study, Hwa-ong project in which dike construct

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Landscape Ecological Approach and the Strategies of Regional Development on South Chung-Chong Coastal Environment (충남 연안의 경관생태적 지역발전 전략)

  • KANG, Tay-Gyoon
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.1
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    • pp.105-116
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    • 2017
  • This article is written in the viewpoint of landscape ecological geography. The coast of South Chung-chong Province will make new characters of region in the development strategies program. This study is to describe geomorphological landscapes of South Chung-chong Province relating with it's environment based on the coast. Although landforms constitute prominent landscape features as tidal flats and rock cliff do, it is nonetheless the features such as beaches, sanddunes, and coastal plains that have various ramifications for human communities. Tidal flats, beaches and coastal sanddunes are special in that their formation is attributable to the combined action of tidal flows, waves and winds. To some extent, the erosion of sand has been a global phenomenon. Human impact are involved. The influence of globalization and expansion of liberal trade appears in regions variously. Individual regions need to secure its competitiveness in the world market. Regions are not value-neutral abstract conception, but must be informal commercialized characters of region. The coast of South Chung-chong Province has experienced rapid and dramatic changes. In industrial times, the middle of west coast Korea turned into a major reclamation at larger scale. Reclaimed land was based on location of industry and mechanized agriculture. The west coast highway and bridges between island and land contributed to the development of west coast transportation. As information society matured, trend and value are changing. Environment and ecology emphasize and rediscover the value of tidal flats and sanddunes. The west coast region now receives attention as eco-tour and sustainable course.

Analysis of Exchangeable Sodium Percentage During Desalinization of Reclaimed Tidal Lands (간척지 토양의 제염과정 중 교환성 나트륨 백분율 분석)

  • Koo Ja Woong;Choi Jin Kyu;Son Jae Gwon
    • KCID journal
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    • v.8 no.1
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    • pp.48-60
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    • 2001
  • This study was performed in order to produce the basic data for the estimation of water requirements for desalinization and developing prediction techniques of desalinization to be applicable in the beginning of tidal land reclamation through analyzing ch

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Desalinization Characteristics after Reclamation of Tidal Flat on the Western Coast of Korea (서해안 간척지 토양의 탈염특성)

  • 민병미;김준호
    • The Korean Journal of Ecology
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    • v.20 no.4
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    • pp.275-283
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    • 1997
  • Vertical and temporal characteristics of desalinized reclaimed soil were analyzed from reclaimed coastal land on the western coast of Korea. Of the vertical changes during desalting, pH valuse were the lowest at the topsoil without regard to reclaimation time. The content of C1 were designated as the early period (the first 2-4 years) which decreased exponentially and the later period(the last 5-7 years) which was almost constant, from top to down. In temporal changes of the soil attributes, pH values increased for 5 years and decreased at 6 year after reclamation. Chlorine leaches more rapidly than Na does, K and Ca are constant but Mg increases as time elapsed after reclamation. Sometimes the content of Ca and K in the reclaimed soil are of higher concentration than that of the seawater after reclamation. During desallinization as exemplified by decreasing EC of the soil, Cl and Na are rapidly leached, but K, Ca and Mg are somewhat enhanced. The ration of Na/Cl in the soil equals 1 when the EC registers 5 mmho and then increases dramatically as the EC decreases. Rapid leaching of $Cl^{-}$ elicits an increasing pH valus. The electrostatic balance of the soil is achived by replacement of $Cl^{-}$ with $OH^{-}$ until stationary or until a decreasing pH value is reached again.

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Analysis of Electrical Conductivity during Desalinization of Reclaimed Tidal Lands (간척지 토양의 제염과정 중 전기전도도 분석)

  • 구자웅;최진규;손재권;윤광식;이동욱;조경훈
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.4
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    • pp.37-49
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    • 2001
  • This study was performed in order to produce the basic data for developing prediction techniques of desalinization to be applicable to reclaimed tidal lands at the beginning stage. the desalinization experiments were carried out by two water management practices, namely, the leaching method by subsurface drainage and the rinsing method by surface drainage. The 5 soil samples used in this study were collected in 4 tidal land reclamation projects. Regression equations were obtained in order to investigate the changes of electrical conductivity during the desalinization of reclaimed tidal lands and to estimate water requirements for desalinization. The results obtained from this study were summarized as follows: 1. According to USDA Salinity Laboratory classification system of salt affected soils the reclaimed tidal land soils used in this study were saline-sodic soils with the high electrical conductivity and the high exchangeable sodium percentage. 2. With the increase of the water requirements for desalinization the electrical conductivity was decreased with high degree of correlationships and the desalinization effects were remakable in both the leaching method and the rinsing method. 3. In case of the leaching method the electrical conductivity had been reduced below the classification value of salt affected soils when the depth o water leached per unit depth of soil (Dwl/Ds) was 0.3 and the desalinization effects showed a tendency to be much the same in each treatment.

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Topography of the Yeongsan River Basin and its Locals' Life (영산강유역의 지형과 주민생활)

  • Beom, Seon-Gyu
    • Journal of the Korean association of regional geographers
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    • v.8 no.4
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    • pp.451-467
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    • 2002
  • The Yeongsan River is one of major rivers in South Korea, and its basin is one of core areas that produce foods for the nation. The Yeongsan River Basin has flood plain and hill areas well developed, and areas surrounding the Yeongsan Lake has a tidal mud-plat widely dispersed. The flood plains are called 'Deul'. In particular, at the upstream of 'Mulmok' with a narrow valley are widely spread flood plain. The flood plains were developed into rice paddies until the end of Joseon Dynasty. Local core cities were created against these agricultural lands. Hills are called 'Deung', 'Kkageum' and 'Yasan' and in particular, are widely distributed in Naju City and Yeongam County. Forest land on hill began to be seriously developed into agricultural land from the 1960s, and this development is being pursued even today. Much fanning are conducted in the form of leased fanning by outside people. Tidal mud-plats were widely distributed along the downstream of the Yeongsan River, Namhae Bay. Tidal mud-plat is called 'BBeolbat' and tidal channel is called 'Gaeong.' After the estuary dyke of the Yeongsan River was built in 1981, the tidal mud-plat was developed into agricultural land in large-scale reclamation projects, and changed into 'Yeongsan Plains,' With the appearance of new plains, locals' life fundamentally changed, turning all villages into pure farm villages.

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