• Title/Summary/Keyword: Tidal Land

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Three Dimensional Analysis Using Digital Elevation Model on the Coastal Landform of the Sacheon Bay, South Sea of Korea (수치고도 모델을 이용한 사천만 해안지역의 3차원 지형분석)

  • Lee, Min-Boo;Kim, Nam-Shin;Han, Kyun-Hyeung
    • Journal of the Korean association of regional geographers
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    • v.9 no.2
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    • pp.203-216
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    • 2003
  • The process of constructing coastal digital elevation model(DEM), for the 3 dimensional analysis, is composed by abstracting land layers for land elevation and water depth, reprojecting UTM, relocating geographical grid, and interpolating works. The geomorphic set of shallow sea, including tidal current, tidal zone deposition, and water depth distribution, was analyzed by eye search of Landsat TM image, masking of land zone, band combination and regression analysis. Some horizontal differences, between combined DEM and surveyed data of shallow sea, was corrected for analysis. Analyzed geomorphic elements are stream channel, alluvial fan, coastal terrace, tidal current. and shallow sea bank. Results of analysis present that transported fluvial materials influence tidal sedimentation, especially from Gahwacheon river, for the role of artificial draining flooding waters from Jinyang Reservoir, almost in the summer season. In the coastal area with less tidal current, more fine materials are deposited. The influence of currental deposition are higher on small pockets with west coast of well developed terraces. The lower skirt of alluvial fans developed into the tidal zone of shallow sea. Small pocket type bays are closed by coastal current, and less influenced from tidal deposition. The bank of Jinju Bay are developed originally from submerging of remnant erosional mountain ranges, and play on the role of trapping fine materials.

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Effect of Subsurface Drainage Systems on Soil Salinity at Saemangeum Reclaimed Tidal Land

  • Lee, Sanghun;Bae, Hui-Su;Lee, Soo-Hwan;Oh, Yang-Yeol;Ryu, Jin-Hee;Ko, Jong-Cheol;Hong, Ha-Chul;Kim, Yong-Doo;Kim, Sun-Lim
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.6
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    • pp.618-627
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    • 2015
  • Soil salinity is the most critical factor for crop production at reclaimed tidal saline soil. Subsurface drainage system is recognized as a powerful tool for the process of desalinization in saline soil. The objective of this study was to investigate the effects of subsurface drainage systems on soil salinity and corn development at Saemangeum reclaimed tidal saline soil. The field experiments were carried out between 2012 and 2014 at Saemangeum reclaimed tidal land, Buan, Korea. Subsurface drainage was installed with four treatments: 1) drain spacing of 5 m, 2) drain spacing 10 m, 3) double layer with drain spacing 5 m and 10 m, and 4) the control without any treatment. The levels of water table showed shorter periods above 60 cm levels with the deeper installation of subsurface drainage system. Water soluble cations were significantly greater than exchangeable forms and soluble Na contents, especially in surface layer, were greatly reduced with the installation of subsurface drainage system. Subsurface drainage system improved biomass yield of corn and withering rate. Thus, the biomass yield of corn was improved and the shoot growth was more affected by salinity than was the root growth. The efficiency of double layer was not significant compared with the drain spacing of 5 m. The economic return to growers at reclaimed tidal saline soil was the greatest by the subsurface drainage system with 5 m drain spacing. Our results demonstrated that the installation of subsurface drainage system with drain space of 5 m spacing would be a best management practice to control soil salinity and corn development at Saemangeum reclaimed tidal saline soil.

Theoretical Analysis of Soil Desalination Characteristics for Underdrain System at Reclaimed Tidal Land (간척지 흙의 암거 설치조건에 따른 제염 특성의 이론적 해석)

  • Kim, Hyuntai;Seo, Donguk;Yoo, Chanho;Kim, Seogyeol
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.3
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    • pp.87-92
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    • 2015
  • Cultivation on reclaimed tidal land is often difficult in the problem such as high salinity of soil, bad drainage because of high level of groundwater. Many researches have been made efforts to solve these problems, but effect of improvement is low and practicality is insufficient. In this study, through numerical analysis of the transport properties of salt and water, we suggested underground drainage of the reclaimed land and the desalination promotion methods in the soil. The results of characteristic of desalination and seepage analysis of underdrain show that underdrain is able to increase twice of the underground seepage amount when installing perforated pipe with horizontal filter (width 50cm) more than installing only the perforated pipe. For soil which coefficient of permeability is below $1{\times}10^{-4}cm/s$ that desalination with pond water is not possible, a method to increase the permeability of the soil is necessary. Therefore, it was concluded that application of underdrain using perforated pipe with horizontal filter would be low-cost and practical.

Vegetation Change Detection in the Sihwa Embankment using Multi-Temporal Satellite Data (다중시기 위성영상을 이용한 시화 방조제 내만 식생변화탐지)

  • Jeong, Jong-Chul;Suh, Young-Sang;Kim, Sang-Wook
    • Journal of Environmental Science International
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    • v.15 no.4
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    • pp.373-378
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    • 2006
  • The western coast of South Korea is famous for its large and broad tidal lands. Nevertheless, land reclamation, which has been conducted on a large scale, such as Sihwa embankment construction project has accelerated coastal environmental changes in the embankment inland. For monitoring of environmental change, vegetation change detecting of the embankment inland were carried out and field survey data compared with Landsat TM, ETM+, IKONOS, and EOC satellite remotely sensed data. In order to utilize multi-temporal remotely sensed images effectively, all data set with pixel size were analyzed by same geometric correction method. To detect the tidal land vegetation change, the spectral characteristics and spatial resolution of Landsat TM and ETM+ images were analyzed by SMA(spectral mixture analysis). We obtained the 78.96% classification accuracy and Kappa index 0.2376 using March 2000 Landsat data. The SMA(spectral mixture analysis) results were considered with comparing of vegetation seasonal change detection method.

Investigation and Complementary Measures Establishment for Flood on Tidal Reclaimed Paddy Fields (간척지 논 침수 원인 조사와 방재 대책 수립)

  • Jeong, Ju-Hong;Yoon, Kwang-Sik;Choi, Soo-Myung;Yoon,, Suk-Gun;Go, Young-Bae;Kim, Young-Taek
    • KCID journal
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    • v.17 no.2
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    • pp.105-114
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    • 2010
  • Tidal land reclamation provided water resources and land for agriculture and contributed stable crop production. However, climate change by global warming disrupts the hydrologic circulatory system of the earth resulting in sea level rise and more frequent flood for reclaimed arable land. Recently, Suyu reclaimed paddy field in Jindo-gun experienced prolonged inundation after heavy rainfall and there is a growing risk of flood damage. Onsite survey and flood analysis using GATE_Pro model of Korea Rural Corporation were conducted to investigate causes of flooding. To perform the analysis, input data such as inflow hydrograph, the lowest elevation of paddy field, neap tide level, management level of Gunnae estuary lake at the time of the flood were collected. Flood analysis confirmed that current drainage facilities are not enough to prevent 20year return period flood. The result of analysis showed flooding more than 24hours. Therefore, flood mitigation alternatives such as sluice gate expansion, installation drainage pumping station, refill paddy land, and catch canal were studied. Replacing drainage culvert of Suyu dike to sluice gate and installing drainage pumping station at the Gunne lake were identified as an effective flood control measures. Furthermore, TM/TC (SCADA) system and expert for gate management are required for the better management of drainage for estuary dam and flood mitigation.

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Improvement of the EIA for Land Reclamation Projects in the Coastal Areas of Korea (해양매립사업 환경영향평가의 개선방안)

  • Jang, Ju-Hyoung;Eom, Ki-Hyuk;Kwon, Kee-Young;Hong, Sok-Jin;Park, Jae-Hyeon;Kim, Gui-Young
    • Journal of Environmental Science International
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    • v.16 no.7
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    • pp.847-853
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    • 2007
  • In Korean coastal areas, land reclamations are main development projects that should be based on environmental impact assessment(EIA), because those human interventions can change coastlines, damage tidal flats, and pollute adjacent areas to threat seafood safety and devaluate overall ecosystem service value. Existing procedures of the EIA for land reclamation projects were diagnosed and evaluated to enhance them. Problems were identified in the designation of survey areas, the consistency in survey sites and periods, the standardization of survey methods and reports, the confidence of survey results and the verification of predictions. Lack of integration was noticeable and could be improved by synthesizing different assessments from topography geography, marine physics, marine chemistry and marine biology. We suggest that successful precautionary marine environment management requires readjusting the cost of EIA, recruiting experts in marine environment, constructing database and establishing specialized assessment system.

Constructed Wetland Design Method to Treat Agricultural Drainage from Tidal Reclaimed Paddy Areas (간척지 논 농업배수 처리에 적합한 인공습지 설계 기법)

  • Jang, Jeong-Ryeol;Shin, Yu-Ri;Jung, Ji-Yeon;Choi, Kang-Won
    • KCID journal
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    • v.18 no.1
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    • pp.4-17
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    • 2011
  • The standard design methodology was suggested to construct wetland system for reducing non-point source pollution from Saemangeum reclaimed paddy land. To set for the design flow and concentrations, runoff and water quality survey were conducted during the irrigation period in 2008 at Gyehwa reclaimed paddy land located at near Saemangeum lake. It is rational that 1ha is the optimum constructed wetland size. To meet this size, the moderate drainage area of reclaimed paddy field was 50ha under the conditions that rainfall is 30mm, average runoff coefficient is 0.83, and runoff capture ratio is 0.6. At these condition, the runoff volume from 50ha was 10,520 $m^3/d$ including base flow during irrigation period. To select the optimum wetland system, several case studies were conducted by focusing on the tidal reclaimed land areas having wetland systems in Seokmun. Pond-Wetland system was selected as the standard model because of showing the highest reduction efficiency. Single variable regression equation were delivered to estimate effluent water concentrations from the designed wetland by using long-term monitoring data from the Seokmun experiment site. The effluent concentration from the designed wetland using these equation were showed moderately range.

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Study on the Desalinization in Tiolal Land (간석지 제람에 관한 연구)

  • 이중기
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.20 no.2
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    • pp.4695-4707
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    • 1978
  • The objeative of this study is to study how to rapidly convert tidal land into cultivable land. The study of a rapid, reasonable desalinization method is conducted at Namyang tidal land which represents soil texture of tidal lands along the south west costa larea of Korea. Therefore, Researches were made at many Pilots in order to find a way of high efficiency of leaching with simpler facilities and cheaper costs. The results of study are briefly summarized as follaws: 1. Subdrainage efficieny is 35%. This is a Poorly drained area, and needs longer leaching desalinization period. 2. The efficieny of desalinization in P.V.C 16 meters plot is the same as that of mole drainage 2 meters plot. P.V.C 4 meters plot has desalinization effect as much as two times compared to P.V.C 16 meters plot. 3. Because the soil texture is silty-clay, desalinization in non-treated plot of sub-drainage and surface drainage desalinization take three times longer period in comparision with P.V.C 4 meters plot. 4. As to the desalinization rate of soluble salt in the soil, the efficieny of desalinization of the topsoil in P.V.C plots was 50% higher than that of mole drainage plot and about 170% higher than that of non-treated plot. In the deep soil salt accumulation at topsoil was observed in non-treated and mole drainage plots, but efficiency in P.V.C polt is about 40 times as high as that of mole drainage and non-treated plot. 5. As to the results of use gypsum and lime as sub-drainage soil improver, gypsum was 60% more efficieny than lime in the continuously inundated plot and 44% in the intermittently inundated plot. The efficieny of gypsum and lime in the intermittently flooded plot is 35% and 42% higher than that of continuously flooded plot reapeaticee1y.

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