• Journal of Korea Water Resources Association
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• v.37 no.11
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• pp.969-978
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• 2004

According to the report of hydrologic modeling study, from a quantitative point of view, a lumped model is more efficient than a distributed model. A distributed model has to simplify geospatial characteristics for the shake of restricted application on computer calculation and field observation. In this reason, a distributed model can not help having some errors of water quantity modelling. However, considering a distribution of rainfall-runoff reflected spatial characteristics, a distributed model is more efficient to simulate a flow of surface water, The purpose of this study is modeling of spatial rainfall-runoff of surface water using grid based distributed model, which is consisted of storage function model and essential basin-channel parameters( slope, flow direction & accumulation), and that procedure is able to be executed at a personal computer. The prototype of this model is developed in Heongseong Multipunose Dam basin and adapted in Hapchon Multipurpose Dam basin, which is larger than the former about five times. The efficiency coefficients in result of two dam basin simulations are more than about 0.9, but ones at the upstream water level gauge station meet with bad result owing to overestimated rating curves in high water level. As a result of this study, it is easily implemented that spatially distributed rainfall-runoff model using GIS, and geophysical characteristics of the catchment, hereafter it is anticipated that this model is easily able to apply rainfall data by real time.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.77-77
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• 2017

전 세계적인 인구증가와 도시화로 메가시티가 점차 증가하고 있으며, 2016년 기준 37개의 메가시티 중 60% 이상(23개)이 아시아 지역에 집중되어 있다. 통상, 메가시티는 불투수율이 높고 인구가 밀집되어 있어 수재해로 인한 피해규모가 크며, 인구증가에 따른 용수부족 및 수질악화로 인해 수자원 확보가 어렵다. 특히, 아시아 지역은 몬순의 영향으로 수자원의 변동성이 크며, 최근 기후시스템의 변화는 몬순의 시 공간적 변동을 증대시킬 것으로 전망된다. 즉, 아시아 몬순지역에 위치하는 메가시티는 기후변화에 더욱 취약하며 이에 따른 수자원 확보 및 수자원 관리의 어려움은 더욱 가중될 것으로 예상된다. 본 연구에서는 AR5 기후변화 시나리오를 활용하여 아시아 몬순지역 내 메가시티를 대상으로 미래기간에 대한 기온, 강수량, 유출량을 전망하고 그 특성을 분석하고자 한다. 국가별 인구 통계자료를 기반으로 아시아 몬순지역 내 존재하는 19개 메가시티를 선정하였다. 기후전망을 위해 테일러 다이어그램을 활용하여 GCMs의 몬순모의 성능을 평가하였으며, 아시아 몬순특성을 잘 반영하는 다수의 GCMs을 선정하였다. 아시아 메가시티를 평가하고자 이중선형보간기법(Bilinear method)을 적용하여 $0.5^{\circ}$ 간격의 공간해상도로 상세화하였으며, Delta method를 이용하여 편의보정을 수행하였다. GCM 모의자료의 편의를 산정하기 위해 APHRODITE의 일단위 강수자료를 이용하였으며, VIC (Variable Infiltration Capacity) 모형을 이용하여 유출량 분석을 수행하였다. 평가결과 각 메가시티의 평균기온, 강수 및 유출량이 모든 미래기간 2020s, 2050s, 2080s에서 다르게 나타났다. 해안/내륙, 경 위도 등 메가시티의 지리적 위치에 따른 변화특성 분석을 수행하였으며, 각 메가시티에 대한 여름 및 겨울철 몬순의 변화 특성을 분석하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.3
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• pp.417-422
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• 2022

It is always desirable that the continuation of power flow through the lines should not be interrupted for a long time. The optimized guideline of reclosers on distribution lines is known to improve the reliability of power systems, the protection functions on distribution systems heavily rely on the number and placement of such reclosers. This study reviewed the effect of using protection settings methodology with the number of reclosing operations to reduce the damage sustained during faults on distribution networks. The aim of the study is to determine the number of reclosing operations and fault current conditions based on simulation data of PSCAD/EMTDC for standard distribution networks. It is found that the determination of the number of operations on reclosers, which are the protection function of feeders, helped to optimize the operation and reliability of distribution networks.

• Journal of Korea Water Resources Association
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• v.55 no.8
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• pp.613-621
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• 2022

Due to the global climate change, the rainfall volume and frequency on the Korean Peninsula are predicted to increase at the end of the 21st century. In addition, impervious surface areas have increased due to rapid urbanization which has caused the urban water cycle to deteriorate. Green Infrastructure (GI) researches have been conducted to improve the water cycle soundness; the efficiency of this technique has been verified through various studies. However, there are still no suitable GI design guidelines for this aspect. Therefore, the rainfall scenarios are set up for each percentile (60, 70, 80, 90) based on the volume and frequency analysis using 10-year rainfall data (Busan Meteorological Station). After determining the GI areas for each scenario, the runoff reduction characteristics are analyzed based on Storm Water Management Model (SWMM) 10-year rainfall-runoff-simulations. The total runoff reduction efficiency for each GI areas are computed to have a range of 13.1~52.1%. As a results of the quantitative analysis, the design rainfall for GI is classified into the 80~85 percentile in the study site.

• Journal of Korea Water Resources Association
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• v.56 no.6
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• pp.419-429
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• 2023

The objective of this study was to determine the management water level of an estuary reservoir considering three aspects: the water use, flood control and water quality, and to use a robust decision-making to consider uncertainty due to climate change. The watershed-reservoir linkage model was used to simulate changes in inflow due to climate change, and changes in reservoir water level and water quality. Five management level alternatives ranging from -1.7 El.m to 0.2 El.m were evaluated under the SSP1, 2, 3, and 5 scenariosof the ACCESS-CM2 Global Climate Model. Performance indicators based on period-reliability were calculated for robust decision-making considering the three aspects, and regret was used as a decision indicator to identify the alternatives with the minimum maximum regret. Flood control failure increased as the management level increased, while the probability of water use failure increased as the management level decreased. The highest number of failures occurred under the SSP5 scenario. In the water quality sector, the change in water quality was relatively small with an increase in the management level due to the increase in reservoir volume. Conversely, a decrease in the management level resulted in a more significant change in water quality. In the study area, the estuary reservoir was found to be problematic when the change in water quality was small, resulting in more failures.

• Journal of Korea Water Resources Association
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• v.49 no.7
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• pp.589-597
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• 2016

In this study, we investigated the use of satellite-derived flow (SDF) signals and a data-based model for the estimation of outflow for the river reach where in situ measurements are either completely unavailable or are difficult to access for hydraulic and hydrology analysis such as the upper basin of Imjin River. It has been demonstrated by many studies that the SDF signals can be used as the river width estimates and the correlation between SDF signals and river width is related to the shape of cross sections. To extract the nonlinear relationship between SDF signals and river outflow, Artificial Neural Network (ANN) model with SDF signals as its inputs were applied for the computation of flow discharge at Imjin Bridge located in Imjin River. 15 pixels were considered to extract SDF signals and Partial Mutual Information (PMI) algorithm was applied to identify the most relevant input variables among 150 candidate SDF signals (including 0~10 day lagged observations). The estimated discharges by ANN model were compared with the measured ones at Imjin Bridge gauging station and correlation coefficients of the training and validation were 0.86 and 0.72, respectively. It was found that if the 1 day previous discharge at Imjin bridge is considered as an input variable for ANN model, the correlation coefficients were improved to 0.90 and 0.83, respectively. Based on the results in this study, SDF signals along with some local measured data can play an useful role in river flow estimation and especially in flood forecasting for data-scarce regions as it can simulate the peak discharge and peak time of flood events with satisfactory accuracy.

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.22-34
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• 2017

The K-DRUM(K-water hydrologic & hydraulic Distributed RUnoff Model), a distributed rainfall-runoff model of K-water, calculates predicted runoff and water surface level of a dam using precipitation data. In order to obtain long-term hydrometeorological information, K-DRUM requires long-term weather forecast. In this study, we built a system providing long-term hydrometeorological information using predicted rainfall ensemble of GloSea5(Global Seasonal Forecast System version 5), which is the seasonal meteorological forecasting system of KMA introduced in 2014. This system produces K-DRUM input data by automatic pre-processing and bias-correcting GloSea5 data, then derives long-term inflow predictions via K-DRUM. Web-based UI was developed for users to monitor the hydrometeorological information such as rainfall, runoff, and water surface level of dams. Through this UI, users can also test various dam management scenarios by adjusting discharge amount for decision-making.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.291-295
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• 2006

비상대처계획(EAP, Emergency Action Plan) 수립 및 홍수위험지도 작성의 목적은 댐.제방 붕괴 등 비상상황이 발생하였을 때 하류부의 생명과 재산 손실을 최소화하기 위한 것으로서 댐 운영 및 관리책임자가 극한홍수 및 지진발생 조건하에서 댐의 물리적, 지형적, 구조적 특성에 따른 발생 가능한 비상상황을 예상하고 이에 효율적으로 대처하기 위한 가능한 최선의 사전계획을 수립하는 것이다. 또한, 댐의 비상상황에 대처하기 위한 비상대처계획 수립 의무화 및 이에 대한 실제적인 모의훈련 등에 필요한 기초자료를 체계적으로 제공하고자 함에 있다. 국내에서 EAP를 수립하여야 할 대상 댐 저수지는 한국수자원공사에서 관리하는 다목적댐, 생공용수댐과 한국농촌공사에서 관리하는 농업용저수지, 한국수력원자력주식회사에서 관리하는 수력발전댐 및 지방자치단체에서 관리하는 댐 등이 해당된다. 제방의 경우 인구가 밀집되어 있는 전 지역이 그 대상이 될 수 있다. EAP의 주요 내용에는 만약에 발생할 수 있는 붕괴 사고시 인명의 손실이나 재산상의 피해를 발생시킬 수 있는 댐 저수지들에 대해서는 EAP를 수립하거나 갱신하기 위한 지침들이 포함되어 있어야 한다. 댐으로부터의 하류 연안지역의 개발이나 소유권은 다양하며, 이로 인해 댐의 운영이나 붕괴로 인한 잠재적 인명손실 또한 다양할 수 있다. 따라서 모든 EAP는 댐, 저수지 하류부 현장 조건에 맞도록 구성되어야 한다. EAP 수립의 주체는 댐 및 저수지 관리자이며 EAP에는 비상상황 확인, 평가, 등급분류, 비상연락체계 및 경보전달체계 수립, 비상시 응급행동요령, 홍수범람예측지도 작성, 비상주민대피계획 및 훈련방안, 부록, 주기적 또는 필요시마다 보완 계획 등이 포함되어야 하며, EAP의 주요 구성요소인 홍수위험지도에는 홍수위험정보 및 대피정보를 제시함으로써 실제 주민 대피계획시 실제적이고 효율적인 대피계획 수립에 활용될 수 있다. 있는 기술가치평가 모형의 구축이 요구된다. 이에 본 연구에서는 효율적인 R&D 투자 정책 수립과 정부정책수립에 기여하고자 AHP(Analytic Hierarchy Process, 계층 분석 과정)기법을 이용, 수자원의 지속적 확보기술의 특성에 따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전략이고, 이 전략의 유용성은 투자자가 설정한 투자기간보다 더욱 긴 분석기간의 주

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.4
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• pp.433-447
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• 2023

There is a growing demand for the stability of existing dams due to abnormal climate and the aging of dams. Emergency Action Plans (EAPs) for reservoir or dam failure only consider a single rainfall event. Therefore, this study simulates dam failure caused by continuous rainfall events, and proposes the establishment of EAP by selecting the optimal shelters. We define a mega rainfall event scenario caused by continuous rainfall events with 500-year frequency in the Chungju Dam watershed and estimate the mega flood. The mega flood event scenario is divided into two cases: scenario A represents the flooding case caused by discharge release from a dam, while scenario B is the case of a dam break. As a result of flood inundation analysis, the flooded damage area by the scenario A is 50.06 km² and the area by the scenario B is 6.1 times of scenario A (307.45 km²). We select optimal shelters for each administrative region in the city of Chungju, which has the highest inundation rate in the urban area. Seven shelter evaluation indicators from domestic and foreign shelter selection criteria are chosen, and Analytical Hierarchy Process (AHP) method is used to evaluate the alternatives. As a result of the optimal shelter selection, the six shelters are selected and five are schools. This study considers continuous rainfall events for inundation analysis and selection of optimal shelters. Also, the results of this study could be used as a reference for establishment of the EAP.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2255-2265
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• 2013

This study presents the width function-based Clark model. To this end, rescaled width function with distinction between hillslope and channel velocity is used as time-area curve and then it is routed through linear storage within the framework of not finite difference scheme used in original Clark model but analytical expression of linear storage routing. There are three parameters focused in this study: storage coefficient, hillslope velocity and channel velocity. SCE-UA, one of the popular global optimization methods, is applied to estimate them. The shapes of resulting IUHs from this study are evaluated in terms of the three statistical moments of hydrologic response functions: mean, variance and the third moment about the center of IUH. The correlation coefficients to the three statistical moments simulated in this study against these of observed hydrographs were estimated at 0.995 for the mean, 0.993 for the variance and 0.983 for the third moment about the center of IUH. The shape of resulting IUHs from this study give rise to satisfactory simulation results in terms of the mean and variance. But the third moment about the center of IUH tend to be overestimated. Clark model proposed in this study is superior to the one only taking into account mean and variance of IUH with respect to skewness, peak discharge and peak time of runoff hydrograph. From this result it is confirmed that the method suggested in this study is useful tool to reflect the heterogeneity of drainage path and hydrodynamic parameters. The variation of statistical moments of IUH are mainly influenced by storage coefficient and in turn the effect of channel velocity is greater than the one of hillslope velocity. Therefore storage coefficient and channel velocity are the crucial factors in shaping the form of IUH and should be considered carefully to apply Clark model proposed in this study.