• Journal of Environmental Science International
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• v.10 no.3
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• pp.217-223
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• 2001

Where no records are available at a site, a preliminary estimate may be made from relations between floods and catchment chatacteristics. A number of these chatacteristics were chosen for testing and were measured for those catchments where mean annual flood estimates were available. Although the improvement using extended data in regression of flood estimates on catchment characteristics was small, this may be due to the limitations of the regression model. When an individual short term record is to be extended, more detailed attention can be given; an example is presented of the technique which should be adopted in practice, particularly when a short term record covers a period which is known to be biassed. A method of extending the peaks over a threshold series is presented with a numerical example. The extension of records directly from rainfall by means of a conceptual model is discussed, although the application of such methods is likely to be limited by lack of recording raingauge information. Methods of combining information from various sources are discussed in terms of information from catchment characteristics supplemented by records. but are generally applicable to different sources of information. The application of this technique to estimating the probable maximum flood requires more conservative assumptions about the antecedent condition, storm profile and unit hydrograph. It is suggested that the profile and catchment wetness index at the start of the design duration should be based on the assumption that the estimated maximum rainfall occurs in all durations centered on the storm peak.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.20-23
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• 2010

본 연구의 목적은 Bhaskar 등(2000)의 연구를 우리나라 유역에 적용하여, 기왕홍수사상에 따른 유출수문곡선의 특성을 이용한 돌발홍수지수(Flash Flood, Index, FFI)를 산정함으로써 유역에서 발생하는 돌발홍수의 심각성 정도를 정량화하고자 하였다. 또한, Bhaskar 등(2000)의 연구내용을 보다 확장하여 미계측유역에서 적용할 수 있는 새로운 돌발홍수지수를 개발하고, 돌발홍수지수와 강우특성과의 상관관계를 정량적으로 분석하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.3
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• pp.381-389
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• 2019

It is important to estimate flood overflow because adverse weather phenomena are frequently occurring in recent years. In order to cope with such abnormal floods, it is essential to perform flood inundation simulations for constructing flood inundation maps as nonstructural countermeasures. However, there is no quantitative evaluation method and criterion for flood inundation prediction. In this study, the Receiver Operation Characteristics (ROC) and Lee Sallee Shape Index (LSSI) were employed to quantitatively evaluate the accuracy of flood inundation maps for 10 administrative districts. Comparing predicted inundation maps with actual inundation trace maps, the ROC score was 0.631 and the LSSI was 25.16 %. Using the ROC and the LSSI, we proposed an evaluation criterion for flood inundation map. The average score was set as an intermediate score and distributed into 5 intervals. The validity of the evaluation criterion was investigated by applying to the XP-SWMM model, which has been verified and corrected. The ROC analysis result was 0.8496 and the LSSI was 51.92 %. It is considered that the proposed evaluation criteria can be applied to flood inundation maps.

• Journal of the korean society of oceanography
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• v.37 no.1
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• pp.10-19
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• 2002

The detailed structure of a tidal front and its ebb-to flood variation in the main tidal channel of the Kyunggi Bay in the mid-west coast of Korea were investigated by analyzing CTD data and drifter trajectories collected in late July 1999. A typical tidal front was formed in water about 60 m deep at the mouth of the channel. Isotherms and isohalines in the upper layer above the seasonal pycnocline in the offshore stratified zone inclined upward to the sea surface to form a surface front, while those in the lower layer declined to the bottom front. The location of the front is consistent with $100 S^3/cm^2$ of the mixing index H/U defined by Simpson and Hunter (1974), where H is the water depth and U is the amplitude of tidal current. The potential energy anomaly in the frontal zone varied at an ebb-to flood tidal cycle, showing a minimum at slack water after ebb but a maximum at slack water after flood. This ebb-to flood variation in potential energy anomaly is not accounted for by the mixing index. We conclude that on- and offshore displacement of the water column by tidal advection is responsible for the ebb-to-flood variation in the frontal zone.

• Journal of Korea Multimedia Society
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• v.16 no.5
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• pp.610-618
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• 2013

The damaged district by flooding has been changed from mainly farmland to cities due to the weather phenomena which is different from the past. This has caused not only irreparable damage of people's lives and property but social infrastructures. There also exist serious damages such as isolation of drivers and traffic jam as the roads were flooded. In this study, we suggested a method to develop a flood risk index focused on not Si, Gun or Gu but roads. In addition, flood risk index in the roads just at the moment, when it rains quantitatively, will be provided by using real-time rainfall information provided by the Weather Center. Then it should be helpful to prevent people from being isolated by flooded roads in advance.

• Journal of the Korean association of regional geographers
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• v.16 no.3
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• pp.216-223
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• 2010

The study deals with classification of drought-flood intensity using Z index based on the precipitation data in Hyesan of the past 50 years(1957~2006). The frequencies of years and four seasons of flood drought and their change features have also been analyzed based on tendency analysis and MESA and wavelet methods. Results show that the annual and seasonal frequencies of flood-drought exceed 24% in Hyesan and flood-drought disasters have been high frequency. Inter-decadal variability seems to be clear in autumn but those of inter-annual variability are obvious in other three seasons and years. Recently the probability of drought disaster become higher in autumn. The flood disaster in other three seasons and years are estimated to become higher in the future.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.1
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• pp.172-183
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• 2012

In 2011, floods were at the worst stage of devastation in Chao Phraya river basin of Thailand. The purpose of this study is to trace the flood inundation area around Chao Phraya river basin by using Terra MODIS image because it has the ability of spatiotemporal dynamics. The MODIS indices, which included the enhanced vegetation index(EVI), land surface water index(LSWI), and the difference in the values of EVI and LSWI(DVEL), were extracted from MODIS product MOD09 8-day composite datasets with a spatial resolution of 500m from Jul. 29, 2011 to Jan. 09, 2012. We found that combined application of EVI, LSWI, and DVEL was suitable for monitoring flood inundation. For the extracted flood inundation area and water-related area. The result can be used to acquire the flood inundation data scattered and demonstrate the potential for the use of MODIS data for temporal and spatial detection of flood effects.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.342-346
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• 2009

홍수피해를 발생시키는 외부적인 요소 측면에서 과거와는 다른 강우특성이 뚜렷이 나타나고 있고, 홍수 피해의 측면에서 홍수에 의한 피해 잠재성이 매우 커지고 있는 시점에서 치수대책은 내 외부적인 여건변화에 민감하게 대처해야 한다. 수자원장기종합계획보고서(국토해양부, 2006)에서는 과거와 같은 제방위주의 치수대책으로는 변화하고 있는 강우상황에 대처할 수 없을 뿐만 아니라 급증하는 홍수피해를 줄이기에는 한계가 있다고 강조하고 있다. 따라서 이와 같은 내 외부적인 환경변화에 대응하기 위해 새로운 패러다임의 홍수대책의 수립이 필요하고, 급변하는 기후변동에 의한 유역의 홍수취약성을 파악하기 위한 지표를 개발하여 치수 정책과 관련 사업의 의사결정을 지원할 수 있는 체계가 뒷받침 되어야 한다. 본 연구에서는 P(Pressure, 압력)-S(State, 현상)-R(Response, 대책) 구성체계를 기반으로 홍수위험지수(Flood Risk Index, FRI)를 개발하여 유역 간 홍수의 취약성 비교 분석을 하고 해당 지역의 주된 취약요인을 파악하여 정부 및 지자체의 치수관련 정책 결정을 효과적으로 지원할 수 있도록 하는데 목적이 있다.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.1
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• pp.31-38
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• 2013

The purpose of this study was to evaluate climate change vulnerability over the agricultural infrastructure in terms of flood and drought using principal component analysis. Vulnerability was assessed using vulnerability resilience index (VRI) which combines climate exposure, sensitivity, and adaptive capacity. Ten flood proxy variables and six drought proxy variables for the vulnerability assessment were selected by opinions of researchers and experts. The statistical data on 16 proxy variables for the local governments (Si, Do) were collected. To identify major variables and to explain the trend in whole data set, principal component analysis (PCA) was conducted. The result of PCA showed that the first 3 principal components explained approximately 83 % and 89 % of the total variance for the flood and drought, respectively. VRI assessment for the local governments based on the PCA results indicated that provinces where having the relatively large cultivation areas were categorized as vulnerable to climate change.

• The Korean Journal of Ecology
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• v.8 no.4
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• pp.205-214
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• 1985

At the Changnyeung natural bod, the flood in the freshwater wetland and the adaptation of the insect at this area were investigated by the species diversity index and the cluster analysis. Most dominant species was Diplonychus esakii collected at the site of the water edge and its dominance index was 0.797. This area had lower species diversity indices with the value of 0.340 to 1.712 than that of the grassland and water stream. The number of the species in this area was not rich. Some ground beetles inhabited at the flooded or wet area were important species for the pair group between the sites by the cluster analysis. The composition of the insect species at this natural wetland affected by the irregular flood was very simple and specific.