• Korean journal of applied entomology
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• v.42 no.4
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• pp.345-352
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• 2003

Studies were conducted to find out the justification for levee-burning, customarily executed by farmers for long time, Experiments were carried out in farmers fields with levee-burning early in the season, and some pesticides spraying when necessary from 1995 to 1997. Some data collected are analysed and discussed from several available aspects of surroundings. In relation to some results obtained together with some previous evidences, levee-burning seems to have several adverse effects on levee destruction, partial cause of forest fire, and lowering of spider density in the field during fall, without providing any benefit, while causing no signifant effect on weed flora on levee, insect density in the field, and incidence of the rice-blast. Therefore, concequently, it could be recommend that the levee-burning by farmers should not be continued.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.20-29
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• 2018

Owing to the changing climate and recent flood events, flood damage caused by river levee collapse and overflow is on the rise in Korea, making it necessary to enhance river levee maintenance technologies to deal with various flood damage scenarios. This paper proposes the evaluation system of a river-levee safety map to improve maintenance efficiency and disaster responsiveness. A river-levee safety map, indicating sliding, piping, visual inspection, scouring, and safety index of a levee fill material on a GIS map will enable the dangerous zone to be identified visually and the development of proactive measures to deal with it. This will maximize the river-levee maintenance efficiency, which is a break from traditional practice in that restoration measures are taken only after the damage has occurred. This study includes scouring and levee fill material in addition to previously-proposed sliding, piping and visual inspections. The research activities conducted in the study include 1) categorization of scouring and levee fill material based on document and data examination, 2) evaluation of sliding and piping at 5 locations on the left levee in the Nam river according to the duration time of the flood water level, and 3) evaluation of the characteristics of scouring and levee fill material at 9 locations on the left/right levee in the Nam River. The river levee safety map proposed in this study would be more useful and practical but further study on the manual for river management organization, repair and reinforcement methods, and budget is required.

• Journal of Korea Water Resources Association
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• v.51 no.spc
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• pp.1161-1169
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• 2018

In this study, a new methodology was proposed to evaluate the flood vulnerability of river levee and to investigate the effect on the levee where the water level changes according to climate change. The stability of levee against seepage was evaluated using SEEP/W model which is two-dimensional groundwater infiltration model. In addition to the infiltration behavior, it is necessary to analyze the vulnerability of the embankment considering the environmental conditions of the river due to climate change. In this study, the levee flood vulnerability index (LFVI) was newly developed by deriving the factors necessary for the analysis of the levee vulnerability. The size of river levee was investigated by selecting the target area. The selected levees were classified into upstream part, midstream part and downstream part at the nearside of Seoul in the Han river, and the safety factor of the levee was analyzed by applying the design flood level of the levee. The safety ratio of the levee was analyzed by applying the design flood level considering the current flood level and the scenario of climate change RCP8.5. The degree of change resulting from climate change was identified for each factor that forms the levee flood vulnerability index. By using the levee flood vulnerability index value utilizing these factors comprehensively, it was finally possible to estimate the vulnerability of levee due to climate change.

• International Journal of Ocean System Engineering
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• v.2 no.4
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• pp.200-208
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• 2012

Surge overflow may cause damage on earthen levees. Levee strengthened on the levee crest and landward-side slope can provide protection against the erosion damage induced by surge overflow. In this paper, surge overflow of a roller compacted concrete RCC strengthened levee was studied in a purely Lagrangian and meshless approach, the smoothed particle hydrodynamics (SPH) method. After verifying the developed model with analytical solution and comparing the results with full-scale experimental data, the roughness and erosion parameters were calibrated. The water thickness, flow velocity, and erosion depth at crest, landward-side slope and toe were calculated. The characteristics of flow hydraulics and erosion on the RCC strengthened levee are given. The results indicate that the RCC strengthened levee can resist erosion damage for a long period.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.319-334
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• 2009

This paper describes an overview of technology and research of dam and levee in Korea. In order to trace the development of dam and levee construction technology, history of design and construction of them is briefly reviewed, and their statistics including type, number and purpose of those hydraulic structures in Korea are dealt with. Furthermore, current status of research on the mentioned structures is also reviewed based on the papers published in Korean societies such as Korean Society of Civil Engineers and Korean Geotechnical Society. Finally state-of-the-art equipment and technology to investigate the safety conditions, and hence to enhance or rehabilitate their stability and dam and levee systems, respectively, are introduced here.

• Journal of the Korea Society of Computer and Information
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• v.21 no.6
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• pp.71-76
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• 2016

In this paper, we propose the mobile visual inspection information system using DGPS and portable range finder for levee safety inspection. Instead of existing visual inspection management method that is stored hand-written data, this system is designed to manage directly the visual inspection information using mobile devices in the field of levee. And through extracting accurate DGPS coordinates information about damage location of levee, this system is developed to ensure efficiency for the main task arising from the levee site such as inspection, maintenance and reinforcement. Furthermore, when damage has occurred at the point that inspector is not able to approach, this system can record the damage site data correctly, by converting data such as position, orientation and height of the damage point into the World Geodetic System coordinates. The position, orientation and height data was extracted automatically through the DGPS and portable range finder. And by applying the augmented reality method, this system was implemented for inspector to revisit the point of damage easily in order to perform the management, maintenance and reinforcement of the levee later.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.41-52
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• 2017

This research conducted the two types of model tests to examine the failure parameters by levee overflow, those were the pilot-scale levee (model height 0.4~0.8 m) and real scale levee (model height 1.0 m). The procedure of levee failure by overflow was succeeded to the following three steps: At first step, the local scouring on levee slope was happened and the overflow velocity was increased slowly. At second step, the enlarged scouring surface and the rapid overflow velocity were succeeded. At last, the levee section was broken totally and the overflow velocity was decreased because of the wide failure surface of levee. The levee failure angle (${\theta}$) was appeared bigger than slope failure angle of Rankine earth pressure. The enlarged levee height (H) made the faster overflow velocity (${\upsilon}$) of the levees, therefore additional tractive force was applied to it, futhermore the failure angle (${\theta}$) and failure surface (A) were enlarged. Because the sand sample for pilot-scale and real scale tests had the same diameter, the critical scouring velocity of each type was also the same, and the scouring properties were governed by variation of overflow velocity.

• Journal of Korea Water Resources Association
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• v.34 no.2
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• pp.141-154
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• 2001

An experimental study was performed to investigate the effects of levee crest width and the slope steepness on levee break due to overtopping flow. The phenomenon of bank failure can be described in 4 stages. In this study, the magnitudes of breach width, breach depth peak discharge, and scouring shape at the break site were measured, and the result shows that peak discharge will be reduced and breach duration extended by widening the crown width and lessening the levee slope steepness. The breach width was narrower and the breach depth deeper, as the levee crest width become wider or the slope steeper. And, the bed scour depth was deeper and steeper, as the levee crest crest width become narrower or the slope milder.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.30-30
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• 2018

Research on mapping levees is an important task for assessing levee stability. The drone imagery acquired in river basins is useful for generating real-time levee maps. This research proposes a robust methodology for mapping levees in river basins using the drone imagery. In the first step, the multiple imagery taken in the test bed was acquired by the drone. Then, the orthorectified image and DEM (Digital Elevation Model) were generated by the photogrammetry and image processing process. Finally, the significant features on levee surfaces such as levee tops, levee lines, levee slopes, eroded areas were detected from the generated DEM and orthorectified image by manual labors and automatic methods. In future research, the automatic procedure for identifying the significant levee features from the drone imagery would be proposed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.144-169
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• 2010

In 2002, property loss caused by failure or leakage of existing river levee structures was about 1.8 trillion in Korean Won, and furthermore in which damages of river structures are getting more severe due to characteristics of extremely extraordinary rain such as torrential rain in the locality or guerrilla heavy rain. In this regards, this paper collects and analyzes those damage records and costs for repair by statistic method, and moreover categorizes the causes of failure, erosion and overtopping of levee structures in large and small scale rivers threatened frequently by typhoon and heavy rainfall. It is believed that the results from the analyses can be used as a basic source in developing criteria of standards for design, construction, maintenance and inspection(or diagnosis) of hydraulic structures such as levee and drain conduit.