• Title/Summary/Keyword: Sand dune

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Analysis of Ground Watertable Fluctuation at the Sandy Barrier Island on Jinu-do in Nakdong River Estuary (낙동강 하구역 진우도 자연해빈의 지하수위 변동해석)

  • Park, Jung-Hyun;Yoon, Han-Sam;Lee, In-Cheol
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.4
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    • pp.382-388
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    • 2014
  • This study selected five observational stations in the normal direction of Jinu-do(island) shoreline and observed water temperature, electrical conductivity and pressure from March, 2012 to January, 2013(about 11 months) and attempted to see the variation characteristics of ground watertable. This study wants to know : 1) External environment force factors(tide, climate, wave etc.) affecting ground watertable variation through time series and correlation analysis. 2) Spatial variations of ground watertable and electrical conductivity change by storm event. First, we found that the station at the intertidal zone was strongly affected by wave and tide level and the stations at sand dune and vegetation zone was affected by precipitation and tide level through time series data and correlation analysis. Second, during the storm event, we found that ground watertable and electrical conductivity are stabilized at the start line of sand dune and vegetation zone and transition zone between freshwater layer and seawater layer exists in the experiment area and is about 50~70 m from coastline of the south side of Jinu-do(island).

Distribution of halophytes in coastal salt marsh and on sand dunes in Korea (한반도 해안염습지와 사구 염생식물 분포)

  • Shim, Hyun-Bo;Cho, Won-Bum;Choi, Byoung-Hee
    • Korean Journal of Plant Taxonomy
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    • v.39 no.4
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    • pp.264-276
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    • 2009
  • To elucidate the distribution of halophytes in Korea, we surveyed 95 coastal salt marsh and sand dune areas. As a result, 62 halophytes of 57 species, 4 varieties and 1 form belonging to 44 genera and 21 families were recorded from coastal regions and islands of South Korea. Of these, 33 taxa were plants growing on sand dunes and the other 29 in salt marsh. Fifty eight taxa were found on the west coast, which was surveyed at 61 areas. The most common species among them were Suaeda glauca (Bunge) Bunge, Suaeda japonica Makino, Phragmites communis Trin., Zoysia sinica Hance, Carex scabrifolia Steud. in salt marsh, and Salsola komarrovii Iljin, Lathyrus japonicus Willd., Limonium tetragonum (Thunb.) A.A. Bulloc, Calystegia soldanella Roem. & Schult. on sand dunes. On the other hand, only 45 taxa were found on the southern coast, surveyed at 15 areas. On the east coast, surveyed at 13 areas, 44 taxa were found. The most common species were Salsola komarrovii Iljin, Lathyrus japonicus Willd., Calystegia soldanella Roem. & Schult., on sand dunes and Linaria japonica Miq., which on the Korean peninsula is found only on the east coast. On Jeju Island, surveyed at 6 areas, 30 taxa of halophytes were found. Canavalia lineata (Thunb.) DC. is found in Korea only on Jeju Island. About half of the Korean halophytes were members of three families (Chenopodiaceae: 12 species, Poaceae: 12 species and Asteraceae: 7 species).

Analysis of Sedimentation and Erosion Environment Change around the Halmi-island, Anmyeondo in West Coast of Korea (안면도 할미섬 주변의 침식·퇴적환경 변화 분석)

  • KIM, Jang-soo;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.2
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    • pp.123-132
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    • 2012
  • In this study, we analyzed sedimentation and erosion environment around Halmiseom on Anmyeon Island using wind direction and wind speed data, gain size analysis data and datum-point measured values. To observe changes in sedimentation and erosion environment around Halmiseon, we installed datum points at 12 locations around Halmiseom and carried out at total of 32 field measurements from May 16th, 2010 to May 8th, 2012. The field measurement results showed that H-3, H-4, H-5 and H-9 points are dominated by sedimentation environment, and H-7, H-8, H-10, H-11 and H-12 points are dominated by erosion environment. Meanwhile, sedimentation and erosion appeared alternately at H-2 and H-6 points. These results indicate that a bank installed in the southwest side of Halmiseom prevented sand of the beach from moving to the northeast side, leaving the sand of the beach being deposited at the sites, and the northeast side, where sand was not provided from beach ridge of Halmiseon was dominated by sedimentation. That is, the southwest side of Halmiseom was dominated by sedimentation, but the northeast side was dominated by erosion in general. However, the opposite trends were observed at H-9 point of the northeast side and H-12 point of the southwest side. According to analysis, since H-9 point is located at the end of sand spit connected to Halmiseom, the supply of sediments by a tidal current is possible. On the other hand, it was difficult to analyze the cause of erosion in case of H-12 point located at the sand dune due to the short measurement period.

Improvement in shear strength characteristics of desert sand using shredded plastic waste

  • Kazmi, Zaheer Abbas
    • Geomechanics and Engineering
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    • v.20 no.6
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    • pp.497-503
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    • 2020
  • In the Kingdom of Saudi Arabia, the shallower depth of the earth's crust is composed of loose dune or beach sand with soluble salts. The expansive behavior of salt bearing soil, fluctuation of ground water table and extreme environmental conditions offer a variety of geotechnical problems affecting safety and serviceability of the infrastructure built on it. Despite spending money, time and other resources on repair and rehabilitation, no significant attention is paid to explore the root causes of excessive differential settlement and cracking to these facilities. The scientific solution required to ensure safety and serviceability of the constructed infrastructure is to improve the strength and durability properties of the supporting ground. In this study, shredded plastic is employed as a low cost and locally available additive to improve strength characteristics of the desert sand. The study shows a remarkable increase in the shear strength and normal settlement of the soil. A seven (07) degree increase in angle of internal friction is achieved by adding 0.4 percent of the shredded plastic additive. The effect of different proportions and sizes of the plastic strips is also investigated to obtain optimum values. Such a long-lived solution will seek to reduce maintenance and repair costs of the infrastructure facilities laid on problematic soil along with reduction of environmental pollutants.