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Sangho Lee
Department of Civil Engineering, Pukyong National University, Busan 48513, Korea

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Journal article
Published: 13 August 2020 in Sustainability
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Rainfall, tide, and wave overtopping can together cause inundation in some coastal areas. However, there have been few cases of inundation analysis considering compound flooding due to the difficulty of the interdisciplinary technique. The purpose of this study is to suggest an analysis technique of compound flooding in coastal areas that links flow simulation tools of coasts and watershed. XP-SWMM was used to analyze rainfall–runoff simulation and 2D surface inundation analysis. A coupled model of ADCIRC and SWAN (ADCSWAN) was used for analyzing expected flow, including wave spectrum, tide, and storm surge from the distant ocean, and the FLOW-3D model was used to estimate the flow and wave overtopping in the coastal area. The analysis technique was applied to Marine City located in Busan, the Republic of Korea, where rainfall and wave overtopping occurred simultaneously during typhoons, and the results were reasonable. The study results are meaningful as they can contribute to the improvement of reproducibility of real phenomena of compound flooding in coastal areas through linked application of flow simulation tools of coasts and watershed.

ACS Style

Sangho Lee; Taeuk Kang; DongKyun Sun; Jong-Jip Park. Enhancing an Analysis Method of Compound Flooding in Coastal Areas by Linking Flow Simulation Models of Coasts and Watershed. Sustainability 2020, 12, 6572 .

AMA Style

Sangho Lee, Taeuk Kang, DongKyun Sun, Jong-Jip Park. Enhancing an Analysis Method of Compound Flooding in Coastal Areas by Linking Flow Simulation Models of Coasts and Watershed. Sustainability. 2020; 12 (16):6572.

Chicago/Turabian Style

Sangho Lee; Taeuk Kang; DongKyun Sun; Jong-Jip Park. 2020. "Enhancing an Analysis Method of Compound Flooding in Coastal Areas by Linking Flow Simulation Models of Coasts and Watershed." Sustainability 12, no. 16: 6572.

Article
Published: 02 March 2019 in Water Resources Management
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The discrete hedging rule which runs through several hedging phases can be an effective method for water supply operation from a reservoir during drought periods. This paper aims to derive two different hedging rule curves of a reservoir: one rule is based on available water that accompanies prediction of the current period inflow and the other rule is based on the beginning storage alone. The current period inflow was obtained by the ensemble streamflow prediction using historical precipitation data. A mixed integer programming algorithm was used to determine hedging rule curves for water supply operation of Hapcheon dam, the Republic of Korea for the period from 1990 to 2005 that included a drought period. Complying with the derived hedging rules, reservoir simulation runs for the period from 2006 to 2010 were performed. The derived hedging rule curves based on the beginning storage were placed higher than the curves based on available water and induced earlier rationing of water supply. The rule based on available water included the current period inflow and its simulation resulted in faster recovery to the normal phase of water supply when the drought ended. The simulation results applying the rule based on available water were 25% better in terms of the total water supply deficit and reliability; they, however, were 5% worse on the vulnerability. When predicted inflow is not reliable, the hedging rule based on the beginning storage might be worth in practical reservoir operation to avoid severer shortage resulted from the bad prediction of the inflow.

ACS Style

Youngkyu Jin; Sangho Lee. Comparative Effectiveness of Reservoir Operation Applying Hedging Rules Based on Available Water and Beginning Storage to Cope with Droughts. Water Resources Management 2019, 33, 1897 -1911.

AMA Style

Youngkyu Jin, Sangho Lee. Comparative Effectiveness of Reservoir Operation Applying Hedging Rules Based on Available Water and Beginning Storage to Cope with Droughts. Water Resources Management. 2019; 33 (5):1897-1911.

Chicago/Turabian Style

Youngkyu Jin; Sangho Lee. 2019. "Comparative Effectiveness of Reservoir Operation Applying Hedging Rules Based on Available Water and Beginning Storage to Cope with Droughts." Water Resources Management 33, no. 5: 1897-1911.

Journal article
Published: 24 February 2018 in Water
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Especially for periods of drought, the higher the accuracy of reservoir inflow forecasting is, the more reliable the water supply from a dam is. This article focuses on the probabilistic forecasting of quarterly inflow to reservoirs, which determines estimates from the probabilistic quarterly inflow according to drought forecast results. The probabilistic quarterly inflow was forecasted by a copula-based Bayesian network employing a Gaussian copula function. Drought forecasting was performed by calculation of the standardized inflow index value. The calendar year is divided into four quarters, and the total inflow volume of water to a reservoir for three months is referred to as the quarterly inflow. Quarterly inflow forecasting curves, conforming to drought stages, produce estimates of probabilistic quarterly inflow according to the drought forecast results. The forecasted estimates of quarterly inflow were calculated by using the inflow records of Soyanggang and Andong dams in the Republic of Korea. After the probability distribution of the quarterly inflow was determined, a lognormal distribution was found to be the best fit to the quarterly inflow volumes in the case of the Andong dam, except for those of the third quarter. Under the threshold probability of drought occurrences ranging from 50% to 55%, the forecasted quarterly inflows reasonably matched the corresponding drought records. Provided the drought forecasting is accurate, combining drought forecasting with quarterly inflow forecasting can produce reasonable estimates of drought inflow based on the probabilistic forecasting of quarterly inflow to a reservoir.

ACS Style

KwangHoon Kim; Sangho Lee; Youngkyu Jin. Forecasting Quarterly Inflow to Reservoirs Combining a Copula-Based Bayesian Network Method with Drought Forecasting. Water 2018, 10, 233 .

AMA Style

KwangHoon Kim, Sangho Lee, Youngkyu Jin. Forecasting Quarterly Inflow to Reservoirs Combining a Copula-Based Bayesian Network Method with Drought Forecasting. Water. 2018; 10 (2):233.

Chicago/Turabian Style

KwangHoon Kim; Sangho Lee; Youngkyu Jin. 2018. "Forecasting Quarterly Inflow to Reservoirs Combining a Copula-Based Bayesian Network Method with Drought Forecasting." Water 10, no. 2: 233.

Hydraulic engineering
Published: 17 March 2017 in KSCE Journal of Civil Engineering
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Levees are facilities constructed along river to protect floodplains against flooding. However, levee failures are also possible if seepage reaches landside surface of the levee. The seepage on the surface of the landside slope can be prevented by efficient design of levee drainage systems. This study aims to show the seepage control potential on levees by installation of perforated drainpipes, which was verified through hydraulic experiments. Scenarios were performed with four different water stages at riverside. For each scenario, the piezometric heads located at the bottom of the experimental levee were measured. The results of the hydraulic experiments showed that the precise positioning of perforated drainpipes is vital since it greatly affects the amount of seepage in the levee. The SEEP/W model that was calibrated and verified with the experiment results was used to suggest appropriate installation location range of the perforated drainpipe. From the numerical simulation, as the central location of perforated drainpipe is closer to landside levee toe horizontally and to foundation surface vertically, the safety of levee was increased from the seepage failure.

ACS Style

Hyeongyu Seo; Taeuk Kang; Micah Lourdes Felix; Sangho Lee. A study to determine the location of perforated drainpipe in a levee for controlling the seepage line. KSCE Journal of Civil Engineering 2017, 22, 153 -160.

AMA Style

Hyeongyu Seo, Taeuk Kang, Micah Lourdes Felix, Sangho Lee. A study to determine the location of perforated drainpipe in a levee for controlling the seepage line. KSCE Journal of Civil Engineering. 2017; 22 (1):153-160.

Chicago/Turabian Style

Hyeongyu Seo; Taeuk Kang; Micah Lourdes Felix; Sangho Lee. 2017. "A study to determine the location of perforated drainpipe in a levee for controlling the seepage line." KSCE Journal of Civil Engineering 22, no. 1: 153-160.

Journal article
Published: 08 January 2017 in Water
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Hydrological responses are being impacted by both climate change and human activities. In particular, climate change and regional human activities have accelerated significantly during the last three decades in South Korea. The variation in runoff due to the two types of factors should be quantitatively investigated to aid effective water resources’ planning and management. In water resources’ planning, analysis using various time scales is useful where rainfall is unevenly distributed. However, few studies analyzed the impacts of these two factors over different time scales. In this study, hydrologic model-based approach and hydrologic sensitivity were used to separate the relative impacts of these two factors at monthly, seasonal and annual time scales in the Soyang Dam upper basin and the Seom River basin in South Korea. After trend analysis using the Mann–Kendall nonparametric test to identify the causes of gradual change, three techniques, such as the double mass curve method, Pettitt’s test and the BCP (Bayesian change point) analysis, were used to detect change points caused by abrupt changes in the collected observed runoff. Soil and Water Assessment Tool (SWAT) models calibrated from the natural periods were used to calculate the impacts of human activities. Additionally, six Budyko-based methods were used to verify the results obtained from the hydrological-based approach. The results show that impacts of climate change have been stronger than those of human activities in the Soyang Dam upper basin, while the impacts of human activities have been stronger than those of climate change in the Seom River basin. Additionally, the quantitative characteristics of relative impacts due to these two factors were identified at the monthly, seasonal and annual time scales. Finally, we suggest that the procedure used in this study can be used as a reference for regional water resources’ planning and management.

ACS Style

Sangho Lee; Sang Ug Kim. Quantification of Hydrological Responses Due to Climate Change and Human Activities over Various Time Scales in South Korea. Water 2017, 9, 34 .

AMA Style

Sangho Lee, Sang Ug Kim. Quantification of Hydrological Responses Due to Climate Change and Human Activities over Various Time Scales in South Korea. Water. 2017; 9 (1):34.

Chicago/Turabian Style

Sangho Lee; Sang Ug Kim. 2017. "Quantification of Hydrological Responses Due to Climate Change and Human Activities over Various Time Scales in South Korea." Water 9, no. 1: 34.

Article
Published: 21 October 2016 in Water Resources Management
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A zone-based operation uses a simple method to make operational decisions based on rules established for storage zones. However, the division of a reservoir into appropriate storage zones involves complicated procedures. Using test functions to compare the three heuristic methods of a genetic algorithm, the shuffled complex evolution method developed by the University of Arizona, and the dynamically dimensioned search (DDS) method, we found that DDS might be useful for determining good global solutions to a problem with many decision variables. Hence, we applied the DDS method to determine three series of water levels for zoned reservoir storage division. The developed reservoir-operating method was applied to Andong Dam in the Republic of Korea. We derived zone boundaries using a generated dam inflow series and performed zone-based operations for validation using historical data under the assumption of known inflow data. The results showed improvements in the water supply reliability and vulnerability compared with historical data. The zone-based operating method derived from the present research could prove valuable because of its simplicity and practicality.

ACS Style

Shinuk Kang; Sangho Lee; Taeuk Kang. Development and Application of Storage-Zone Decision Method for Long-Term Reservoir Operation Using the Dynamically Dimensioned Search Algorithm. Water Resources Management 2016, 31, 219 -232.

AMA Style

Shinuk Kang, Sangho Lee, Taeuk Kang. Development and Application of Storage-Zone Decision Method for Long-Term Reservoir Operation Using the Dynamically Dimensioned Search Algorithm. Water Resources Management. 2016; 31 (1):219-232.

Chicago/Turabian Style

Shinuk Kang; Sangho Lee; Taeuk Kang. 2016. "Development and Application of Storage-Zone Decision Method for Long-Term Reservoir Operation Using the Dynamically Dimensioned Search Algorithm." Water Resources Management 31, no. 1: 219-232.