• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.391-399
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• 2005

The purpose of this study is to evaluate hydrological impact by the land cover change of typhoon damage. For the typhoon RUSA (rainfall 1,402 mm) occurred in 2002 (August $31\;{\sim}$ September 1), satellite images of Landsat 7 ETM+ of September 29, 2000 and Landsat 5 TM of September 11, 2002 were selected, and each land cover was classified for Namdae-cheon watershed $192.7km^2$ located in the middle-eastern part of Korea Peninsula. SCS unit hydrograph for watershed runoff and Muskingum for streamflow routing of WMS HEC-1 was adopted. 30m resolution DEM & hydrological soil group using 1:50,000 soil map were prepared. The model was calibrated using three available data of storm events of 1985 to 1988 based on 1985 land cover condition. To predict the streamflow change by damaged land cover condition, rainfall of 50 years to 500 years frequency were generated using 2nd quantile of Huff method. The damaged land cover condition treated as bare soil surface increased streamflow of $50.1\;m^3/sec$ for 50 years rainfall frequency and $67.6\;m^3/sec$ for 500 years rainfall frequency based on AMC-I condition. There may be some speedy treatment by the government for the next coming typhoon damage.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.149-156
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• 2019

Assessing the hydrological safety of existing dams against climate change and providing appropriate adaptation measures are important in terms of sustainable water supply and management. Korean major dams ensure their safety through periodic inspections and maintenance according to 'Special Act on the safety control and maintenance of establishments'. Especially when performing a full safety examination, principal engineer must assess the hydrological safety and prepare for potential risks. This study employed future probable maximum precipitation (PMP) estimated using outputs of regional climate models based on RCP4.5 and RCP8.5 greenhouse-gas emission scenarios to assess climate change impact on existing dam's future hydrological safety. The analysis period was selected from 2011 to 2040, from 2041 to 2070, and from 2071 to 2100. Evaluating the potential risk based on the future probable maximum flood (PMF) for four major dams (A, B, C, I) showed that climate change could induce increasing the overflow risk on three dams (A, B, I), although there are small differences depending on the RCP scenarios and the analysis periods. Our results suggested that dam managers should consider both non-structural measures and structural measures to adapt to the expected climate change.

• Journal of Climate Change Research
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• v.6 no.2
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• pp.121-131
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• 2015

As the temperature has changed by climate change, changes in its own characteristic values of the chemical substance or the movement and distribution of chemicals take place in accordance with the changes of hydrological and meteorological phenomena. Depending on the impact of climate change on the chemical behavior, it is necessary to understand and predict quantitative changes in the dynamics of the environment of pollutants due to climate change in order to predict in advance the occurrence of environmental disasters, and minimize the impact on the life and the environment after the incident. In this study, we have analysed and compared chemical fate models validated by previous studies in terms of model configuration, application size and input/output factors. The potential models applicable to municipal and industrial areas were selected on the basis of characteristic of each model, availability of input parameters and consideration for climate change, identified the problems, and then presented an approach to improve applicability.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.384-393
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• 2012

Saemangeum lake is an artificial lake created by reclamation works and an estuary embankment since 2006. The sea water flows into the lake by the operation of two sluice gates, and the freshwater enters into the lake by the upper streams. For the reflection of hydrology and hydrodynamics effects in Saemangeum area, a hydrodynamics model was developed by connecting Hydrological Simulation Program with Fortran (HSPF) and Environmental Fluid Dynamic Code (EFDC). The HSPF was applied to simulate the freshwater discharge from the upper steam watershed, and the EFDC was performed to compute water flow, water temperature, and salinity based on time series from 2008 to 2009. The calibration and validation are performed to analyze horizontal and vertical gradients. The horizontal trend of model simulation results is reflected in the trend of observed data tolerably. The vertical trend is conducted an analysis of seasonal comparisons because of the limitation of vertically observed data. Water temperature reflects on the seasonal changes. Salinity has an effect on the near river input spots. The impact area of salinity is depending on the sea water distribution by gate operation, mainly.

• Journal of Korea Water Resources Association
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• v.44 no.5
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• pp.351-362
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• 2011

The soil moisture measurements and correlation analysis are presented to improve understanding the hydrological process at the hillslope scale. The rainfall events is a main driver of soil moisture variation, and its stochastic characteristic need to be properly treated prior to the correlation analysis between soil moisture measurements. Using field measurements for two designated periods during the late summer and autumn seasons in 2007 obtained from the Bumrunsa hillslope located at the Sulmachun watershed, prewhitened correlation analysis were performed for 8, 14, 7 and 7 relationships representing the vertical, lateral, recharge and return flows, for two designated periods, respectively. The analysis indicated both temporal and spatial variation patterns of hydrological processes, which can be explained by the relative contribution of matrix and macropore flows and the impact of transect topography, respectively.

• Journal of Korea Water Resources Association
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• v.35 no.2
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• pp.125-136
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• 2002

The effects of the temporal scale of input hydrological data on runoff simulation have been studied using hydrological data with various time scales. TOPMODEL has been employed to explores these effects. The Genetic a1gorithm was used to calibrate model Parameters. The results of sensitivity analysis in various time scales provide the insight of parameter space for TOPMODEL operation of different time scale. The variation of temporal scale of input hydrological data appeared to have significant impacts on the model efficiency, average water table depth, the ratio of the surface runoff to the total runoff and the calibrated parameters. Generally, the longer the time scale, the more surface runoff and the less average water table death were calculated. It is found that the impact of lime scale to runoff simulation results from the structure of TOPMODEL and the hydrographic morphology.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.143-148
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• 2005

The main purpose of this study is to suggest and evaluate an operational method for assessing the potential impact of climate change on hydrologic components and water resources of regional scale river basins. The method, which uses large scale climate change information provided by a state of the art general circulation model(GCM) comprises a statistical downscaling approach and a spatially distributed hydrological model applied to a river basin located in Korea. First, we construct global climate change scenarios using the YONU GCM control run and transient experiments, then transform the YONU GCM grid-box predictions with coarse resolution of climate change into the site-specific values by statistical downscaling techniques. The values are used to modify the parameters of the stochastic weather generator model for the simulation of the site-specific daily weather time series. The weather series fed into a semi-distributed hydrological model called SLURP to simulate the streamflows associated with other water resources for the condition of $2CO_2$. This approach is applied to the Yongdam dam basin in southern part of Korea. The results show that under the condition of $2CO_2$, about $7.6\% of annual mean streamflow is reduced when it is compared with the observed one. And while Seasonal streamflows in the winter and autumn are increased, a streamflow in the summer is decreased. However, the seasonality of the simulated series is similar to the observed pattern and the analysis of the duration cure shows the mean of averaged low flow is increased while the averaged wet and normal flow are decreased for the climate change.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.321-321
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• 2020

도시화로 인해 유역의 불투수면적이 증가함에 따라 수문학적 요소와 수질에 큰 변화를 가져왔다. 불투수면적의 증가는 강우시 지표유출의 증가, 토양층 침투 차단으로 인한 지하수 재충전 감소 및 지하수위 감소를 초래하여 결과적으로 기저유출을 감소시킨다. 이러한 증가된 불투수면적이 강우유출수의 수문 및 수질에 미치는 영향을 완화하기 위해 최근 저영향개발 (Low Impact Development; LID) 기법이 개발되어 적용되고 있다. LID 기법은 개발 이전의 수문순환 상태에 최대한 근사하도록 개발하는 기법으로 우수 유출 속도 감소, 유역에서의 저류, 침투 및 증발산 과정 촉진, 하류로의 오염물질을 저감시킨다. 효과적인 저영향개발 기법 적용을 위해서는 시설 설치 전 모형을 이용한 저영향개발 기법의 적용 효과를 파악해야 한다. 이에 따라 많은 저영향개발 기법 모형들이 개발되었으며, 그 중 SWMM (Storm Water Management Model) 모형이 LID 효과분석을 위해 많이 이용되고 있다. 그러나 SWMM 모형의 경우, 저영향개발 기법으로 모의되는 침투 후 토양 물 흐름이 토양의 수분 조건을 고려하지 않고 모의가 되고 있다. 본 연구에서는 HSPF(Hydrological Simulation Program: FORTRAN) 모형을 이용하여 LID 시설 내에서의 저류현상을 구현하고 수문요소에 대한 영향을 분석하고자 한다. HSPF 모형의 입력자료를 구축하여 모형을 구축하고 LID 모형 적용 전에 모형의 보정 및 검정을 수행하였으며, LID 시설을 적용하여 유역내 수문요소들의 변화를 분석하였다. 본 연구의 결과는 향후 LID 효과 분석을 위한 기초자료로 활용될 수 있을 것으로 사료된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.311-311
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• 2021

최근 도시화에 따라 불투수 면적이 증가하였고 이는 유역의 수문학적 요소와 수질의 큰 변화를 발생시켰다. 불투수면적의 증가는 강우 시 더 많은 강우유출수를 발생시켜 지표유출과 첨두유량을 증가시키고 더 많은 비점오염물질이 하천에 유입되게 한다. 또한, 토양으로의 침투량과 저류량이 감소되어 기저유출을 감소시키며 수질문제를 야기한다. 이러한 문제의 해결책으로 저영향개발 (Low Impact Development; LID) 기법이 개발되어 적용되고 있다. LID는 도시개발 이전의 수문상태와 유사하도록 개발하는 기법으로 우수 유출 속도 감소, 유역에서의 저류, 침투 및 증발산과정 촉진, 하류로의 오염물질을 저감시킨다. 실제 유역에 저영향개발 기법을 적용하기 전에 저영향개발 기법의 적용 효과의 분석은 필수적이다. 이에 따라 많은 LID 기법 모형들이 개발되어 LID 효과분석을 위해 많이 이용되고 있다. 본 연구에서는 HSPF (Hydrological Simulation Program-FORTRAN) 모형을 이용하여 LID시설 내에서의 저류현상을 구현하고 LID 기법 적용에 따른 유역의 수문요소 및 수질에 대한 영향을 분석하고자 한다. 연구대상지로는 불투수면적률이 높은 굴포천을 선정하였으며, LID 기법 적용 전 유역의 수문, 수질 실측치를 이용하여 모형의 보정 및 검정을 수행하였다. HSPF 모형내에 LID 시설을 적용하여 유역내 수문요소와 수질의 변화를 분석하였다. 본 연구의 결과는 향후 LID 효과 분석을 위한 기초자료로 활용될 수 있을 것으로 사료된다.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.168-185
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• 2015

The thermal-hydrological-mechanical (T-H-M) behavior of rock mass surrounding a large-scale high-temperature cavern thermal energy storage (CTES) at a shallow depth has been investigated, and the effects of hydrological conditions such as water table and rock permeability on the behavior have been examined. The liquid saturation of ground water around a storage cavern may have a small impact on the overall heat transfer and mechanical behavior of surrounding rock mass for a relatively low rock permeability of $10^{-17}m^2$. In terms of the distributions of temperature, stress and displacement of the surrounding rock mass, the results expected from the simulation with the cavern below the water table were almost identical to that obtained from the simulation with the cavern in the unsaturated zone. The heat transfer in the rock mass with reasonable permeability ${\leq}10^{-15}m^2$ was dominated by the conduction. In the simulation with rock permeability of $10^{-12}m^2$, however, the convective heat transfer by ground-water was dominant, accompanying the upward heat flow to near-ground surface. The temperature and pressure around a storage cavern showed different distributions according to the rock permeability, as a result of the complex coupled processes such as the heat transfer by multi-phase flow and the evaporation of ground-water.