• Journal of Wetlands Research
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• v.21 no.spc
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• pp.134-140
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• 2019

In this study, we propose a new method for evaluating the vulnerability to flooding river levee. The purpose of this study is to examine how to apply the factors necessary to calculate the proposed levee flood index. To do this, the safety flood level was analyzed by applying the planned flood level. The levee flood vulnerabilities index was calculated based on seven factors such as freeboard, levee crown section, levee section ratio, safety factor, raised spot length, Seepage line change degree, and critical velocity. The Levee Flood Vulnerability Index(LFVI) of the levee developed in this study was used to levee vulnerability analysis. The results of the analysis were divided into 1 to 7 grades using Levee Flood Vulnerability Index(LFVI).

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.857-868
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• 2019

A flooded rice field is one of the significant sources of anthropogenic methane (CH₄) with the intensity of the emissions dependent on management practices. Incorporation of rice straw, which is one of the organic amendments, induces the increase of methane emissions during the flooding season. In this study, we measured of methane emission according to applications of rice straw in different soil textures during a cultivation period in 2017 and 2018. The fallow treatments were non application of rice straw (NA), spring plowing after spring spreading of rice straw (SPSA), spring plowing after previous autumn spreading of rice straw (SPAA), and autumn plowing after previous autumn spreading of rice straw (APAA). The SPSA treatment emitted the highest total methane from loam soil in both 2017 (596.7 CH₄ kg ha^-1) and 2018 (795.4 CH₄ kg ha^-1). The same trend was observed in silt clay loam soil; the SPSA treatment still emitted the highest amount of methane in both 2017 (845.9 CH₄ kg ha^-1) and 2018 (1,071.7 CH₄ kg ha^-1). The lowest emission among the rice straw incorporated plots came from the APAA treatment for both soil texture types in all the seasons. The conversion factors of the SPAA were 0.79 and 0.65 from the loam and silt clay loam soils, respectively. Relatedly, the conversion factors of the APAA were 0.71 and 0.43 from the loam and silt clay loam soils, respectively. The above observations mean therefore that incorporation of rice straw early in the fallow reduces methane emissions in the main rice growing season.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.5
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• pp.16-28
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• 2007

In this study, the implications for landscape architecture in the restoration Project of Cheonggyecheon will be shown through the analysis of factors for landscape architect scheme modification. The method of study consists of theoretical study, analysis of the plan and design of landscape architecture of the restoration project of Cheonggyecheon, and deduction of implications thereof. The controversial feints included the many difficulties in realizing the productive design of landscape architecture due to the selective collecting of public opinion and the problems of settling the complications, the design limit of the turnkey and MA systems, the lack of hydraulic knowledge and technology and the shortage of vegetation monitoring data and experimental materials. The alternative proposals are as follows: 1) there should be agreement between the government organization and the civil group, 2) in the turnkey bidding for the river restoration projects, the river restoration design based on the volume divided into some parts should be reconsidered in order to maintain consistency in the total design, 3) in order to maintain consistency in the planning policies, MA designs should also be introduced and applied from the first stage of the project through its completion, and 4) data such as the safe water level in case of flooding for the facilities and the vegetation and data in connection with the ecological restoration of river should be accumulated. If these controversies are not settled effectively, the river restoration project will be delayed due to complications with the citizens and wasted time and effort will result from the frequent design changes. In addition, landscape architecture in this kind of restoration project is bound to decrease in the future due to frequent changes in the hydraulic-centered design.

• KCID journal
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• v.14 no.1
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• pp.57-66
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• 2007

Temporal changes in total nitrogen (T-N) and phosphorus (T-P) concentrations in paddy floodwater in response to fertilization under rain-shielding pot and small-scaled field conditions were investigated. On the basis of the changing patterns, suggestions for the use of fertilization factors, such as days after fertilization, in developing models for the estimation of T-N and T-P loads from paddy fields were made. Total N concentration was susceptible to fertilization, showing a peak concentration right after fertilization followed by a decreasing pattern with the elapse of days after fertilization. The decreasing pattern of T-N concentration followed the first- order kinetics, indicating that the models are likely to be an exponential equation using days after fertilization as an independent variable. Comparison between the pot and field experiments conducted with soils different in soil fertility revealed that indigenous soil N concentration significantly affected T-N concentration, and this suggests that soil N status can be used as the second variable for the models. Meanwhile, temporal changes in T-P concentration did not respond to P fertilization as sensitively as T-N. In combination with other published results, our study suggests that rainfall intensity and other factors associated with farming activities that are likely to cause disturbance of soil particles containing P may be used as possible variables for the models.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.117-125
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• 2013

Flooding of riparian groundwater caused by changes in rainfall patterns has become a critical problem in areas of agricultural and arable land. Therefore, quantitative analysis of direct runoff and baseflow, which are the most important factors in determining the flow rate of a river, is required to clarify the flooding mechanisms of riparian groundwater. In this study, baseflow obtained using the WHAT system of hydrograph analysis based on Web GIS, and baseflow measured from direct runoff were quantitatively analyzed. Baseflow during the rainy season was 0.489 $m^3/s$ on 17 July 2012, 0.260 $m^3/s$ on 18 July 2012, and 0.279 $m^3/s$ on 19 July 2012, while that during the dry season was 0.006 $m^3/s$ on 6 March 2013 and 0.009 $m^3/s$ on 30 March 2013. The results show that an increase in baseflow occurred during the rainy season in the alluvial area of a riparian zone, and that the measurement error was less during the dry season than during the rainy season.

• Journal of Environmental Policy
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• v.5 no.4
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• pp.1-18
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• 2006

Recently, the damage by fresh flood increases in Gangwon-do and Gyeongsangbuk-do of the north-eastern area of Korea. Even though the recent pattern of rain fall keeps changing, there is no strategy to mitigate damage by disaster. For the appropriate measure and policy for decreasing damage, an index for vulnerability is necessary to provide evidence of local climate change. The present work analyzes the flooding damage cost during the past 20 years. During 80's, the southern area of Korea was seriously damaged by over-floods on the agricultural ground. After that time, the loss and damage has decreased in the southern area but the middle part has shown slight but distinct increases of damage. The absolute coast of damage in the northern part has kept constant. However, the relative regional damage to the total country damage has kept increasing over 20 years in the same area. The surface area of floods is strongly correlated with the regional damage cost in the southern part but the north-eastern part has weak correlation between flooded area and cost. It implies that the recent damage in the north-eastern mountain area was not caused by flood itself but the other factors such as avalanches. The present work expects that the damage cost can be a good proxy value for index for climate change impact assessment.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.66-71
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• 2000

Effect of temperature on resting spore germination of Plasmodioprora brassicae was indirectly estimated based on examining temporal change of number of inactive resting spores. Resting spore germination was the highest at $28^{\circ}C$ reaching 55.6% and 82.5%, 24hr and 132hr after treatment, respectively. Optimum pH for resting spore germination was pH6, following pH7 and pH8, and the germination was inhibited at pH 4, and pH9. termination of resting spores was stimulated by root extracts of radish, Chinese cabbage and kidney bean, but inhibited by that of lettuce. Number of inactive resting spores was increased as temperature increases and time prolongs after temperature treatment. However, degree of inactivation of resting spores after 1hr at $40{\sim}65^{\circ}C$ was similar with $40{\sim}60%$, but rapidly increased to 91.5% at $70^{\circ}C$. When root galls were submerged in water, density of inactive resting spores was increased rapidly and reached 60.3% 9 days after treatment. Flooding of infested soil resulted in 30% reduction of survived resting spores 5 months later. Among the two registered fungicides, fluazinam was better for inactivation of resting spores than flusulfamide, but both fungicides were inferior to phosphoric acid.

• The Journal of the Korea Contents Association
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• v.20 no.7
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• pp.404-416
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• 2020

Flooding is an unavoidable natural disaster for the city. Flood disasters seriously undermine the city's economy, safety, and sustained development. In the course of development and construction of waterfront space in the same city, the construction of basic disaster prevention facilities cannot be avoided completely even if huge amounts of capital are invested to reduce the economic damage of flooding. The cost of rebuilding the city after the disaster is much higher than the cost of building disaster prevention facilities. In recent years, the theory of elasticity in urban reconstruction and so on has been a subject of city problem solving, creating widespread discussion and attention in academia. In other words, how to transform the concept of elasticity into practice based on theoretical and empirical factors is a real problem facing urban disaster. Through theoretical literature on the waterfront (space) buffer zone of a city (flood-weak area) and the case study of the city's practice, this paper tries to clarify the element of 5R, the theory of elastomeric fire prevention, and present detailed measures accordingly. In addition, the following two problems are addressed while emphasizing the feasibility of implementing the urban waterfront (space) plan of the elastomeric element around the urban water buffer zone. First, the means of disaster prevention planning are used to mitigate conflicts between individual utility of urban waterfront and disaster prevention functions in waterfront buffer zones, and second, the waterfront buffer zone can respond to flood-causing problems in terms of disaster prevention as much as possible through the elastic disaster prevention plan.

• Journal of Korea Water Resources Association
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• v.46 no.1
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• pp.47-58
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• 2013

Recently, an increase in the occurrence of sudden local flooding of great volume and short duration due to global climate changes has occasioned the significant danger and loss of life and property in Korea as well as most parts of the world. Such a local flood that usually occurs as the result of intense rainfall over small regions rises quite quickly with little or no advance warning time to prevent flood damage. To prevent the local flood damage, it is important to quickly predict the flood severity for flood events exceeding a threshold discharge that may cause the flood damage for inland areas. The aim of this study is to develop the NFI (New Flood Index) measuring the severity of floods in small ungauged catchments for use in local flood predictions by the regression analysis between the NFI and rainfall patterns. Flood runoff hydrographs are generated from a rainfall-runoff model using the annual maximum rainfall series of long-term observations for the two study catchments. The flood events above a threshold assumed as the 2-year return period discharge are targeted to estimate the NFI obtained by the geometric mean of the three relative severity factors, such as the flood magnitude ratio, the rising curve gradient, and the flooding duration time. The regression results show that the 3-hour maximum rainfall depths have the highest relationships with the NFI. It is expected that the best-fit regression equation between the NFI and rainfall characteristics can provide the basic database of the preliminary information for predicting the local flood severity in small ungauged catchments.

• Journal of the Korean association of regional geographers
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• v.19 no.4
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• pp.615-626
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• 2013

In this study, spatial patterns of the urban flood vulnerability index in Seoul are examined by considering climate exposure, sensitivity, and adaptability associated with floodings for recent 5 year (2006~2010) period by the smallest administrative unit called Dong. According to the results of correlation analyses based on the IPCC(Intergovernmental Panel on Climate Change)'s vulnerability model, among many variables associated with urban flooding, rainwater tank capacity, 1-day maximum precipitation and flood pumping station capacity have statistically-significant, and relatively-high correlations with the number of flood damage in Seoul. The flood vulnerability map demonstrates that the extensive areas along Anyang and Joongnang streams show relatively high flood vulnerability in Seoul due to high sensitivity. Especially in case of Joongnang stream areas, climatic factors also contribute to the increase of flood vulnerability. At local scales, several Dong areas in Gangdong-gu and Songpa-gu also show high flood vulnerability due to low adaptability, while those in Gangnam-gu do due to high sensibility and climate factor such as extreme rainfall events. These results derived from the flood vulnerability map by Dong unit can be utilized as primary data in establishing the adaptation, management and proactive policies for flooding prevention within the urban areas in more detail.