• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.412-418
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• 2000

The purpose of this study is estimation of daily runoff in the watershed with insufficient hydrological data using tank model. In order to estimate, twentysix watersheds were selected to calibrate tank model parameters that were defined by a trial and error method. Results were correlated with characteristics of watershed. Relationships between the parameters and the watershed characteristics were derived by a multiple regression analysis. The simulation results were in agreement with the observed data.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.3
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• pp.37-46
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• 2013

Similarity measure of catchments is essential for regionalization studies, which provide in depth analysis in hydrological response and flood estimations at ungauged catchments. However, this similarity measure is often biased to the selected catchments and is not clearly explained in hydrological sense. This study applied a type of hydrological similarity distance measure-Flood Estimation Handbook to 25 Geum River catchments, Korea. Three Catchment Characteristics, Area(A)-Annual precipitation(SAAR)-SCS Curve Number(CN), are used in Euclidian distance measures. Furthermore, six index of Flow Duration Curve are applied to clustering analysis of SPSS. The catchments' grouping of hydrological similarity measures suggests three groups (H1, H2 and H3) and the four catchments are not grouped in this study. The clustering analysis of FDC provides four Groups; F1, F2, F3 and F4. The six catchments (out of seven) of H1 are grouped in F1, while Sangyeogyo is grouped in F2. The four catchments (out of six) of H2 are also grouped in F2, while Cheongju and Guryong are grouped in F1. The catchments of H3 are categorized in F1. The authors examine the results (H1, H2 and H3) of similarity measure based on catchment physical descriptors with results (F1 and F2) of clustering based on catchment hydrological response. The results of hydrological similarity measures are supported by clustering analysis of FDC. This study shows a potential of hydrological catchment similarity measures in Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.135-143
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• 2020

Natural drought is a three-dimensional phenomenon that simultaneously evolves in time and space. To evaluate the link between meteorological and hydrological droughts, we defined a drought event from a three-dimensional perspective and analyzed the propagation characteristics in time and spaces. Overall results indicated that 77 % of the total cases of spatio-temporal droughts was propagated based on the single category relationship between meteorological and hydrological drought events, while 23 % was affected by multiple meteorological drought events to the occurrence of hydrological drougts. Especially, it turned out that the hydrological drought was caused by the spatio-temporal effects of the propagation of four meteorological drought events generated due to long-term lack of precipitation in 1994-1995. In addition, the meteorological drought caused by the lack of precipitation in the summer of 2001 lasted for several months, and was propagated to the hydrological drought in April 2002.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.303-305
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• 2022

In Korea, due to the geographical and hydrological characteristics of the country, the water cycle has a large variation throughout the year. Therefore, in order to quickly identify and prepare for hydrological phenomena such as floods and droughts, the need for scientific water management incorporating the latest ICT technologies is growing. Accordingly, K-water operates a real-time Hydrological Data Acquisition and Processing System (HDAPS) that can check the situation of the site more intuitionally by linking the hydrological data collected in real time through satellite, GIS, and CCTV. and prepared for flood and drought. In this paper, we will introduce K-water's real-time hydrological information system and consider its application to protect people's lives and property.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.373-384
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• 2020

Hydrological models are based on a combination of parameters that describe the hydrological characteristics and processes within a watershed. For this reason, the model performance and accuracy are highly dependent on the parameters. However, model uncertainties caused by parameters with stochastic characteristics need to be considered. As a follow-up to the study conducted by Choi et al (2020), who developed a relatively simple semi-distributed hydrological model, we propose a tool to estimate the posterior distribution of model parameters using the Metropolis-Hastings algorithm, a type of Markov-Chain Monte Carlo technique, and analyze the uncertainty of model parameters and simulated stream flow. In addition, the uncertainty caused by the parameters of each version is investigated using the lumped and semi-distributed versions of the applied model to the Hapcheon Dam watershed. The results suggest that the uncertainty of the semi-distributed model parameters was relatively higher than that of the lumped model parameters because the spatial variability of input data such as geomorphological and hydrometeorological parameters was inherent to the posterior distribution of the semi-distributed model parameters. Meanwhile, no significant difference existed between the two models in terms of uncertainty of the simulation outputs. The statistical goodness of fit of the simulated stream flows against the observed stream flows showed satisfactory reliability in both the semi-distributed and the lumped models, but the seasonality of the stream flow was reproduced relatively better by the distributed model.

• Spatial Information Research
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• v.10 no.1
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• pp.107-122
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• 2002

Hydrological characteristics would be utilized to apply such as hydrologic modelling or basin management. This study is to extract hydrological characteristics through DEM and stream network analysis using a hydrologic unit map and digital topographic map in Milyang river basin. OEM and stream network was generated from digital topographic map. Especially stream network was allowed direction, stream order, and topology. As a result of the study, it shows that Milyang river has been changing geologically mature stage into old phase and the landform of Milyang river correspond to Horton-Strahler's law on morphology of stream. This methodology can be applicable to other areas related to hydrological characteristics with vector data.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.3
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• pp.42-53
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• 1998

About 50 percent of irrigation and drainage facilities in our country are deteriorated as they were constructed over 40 years ago. Worsening the problems in function might be caused by these facilities' constant exposure to the elements. With these reason, efficient maintenance and management of irrigation and drainage facili- ties are required. A computerized system is tailored on the basis of the each characteristics'data of irrigation and drainage facilities. The unified management system to be introduced in this study is a package program consisting of three subprograms. Facility Management(FM) system, the first component, is a relational database system for image processing and registering the characteristics of irrigation and drainage facilities. The objective of this program is to manage the ledger of each facilities and to scan the characteristics of facilities. Telemeter(TM) system, the second component, monitors and processes the data from the sensors statistically. This system is preprogramed for the complete design of TC/TM system. Hydrological Data Management(HDM) system, the third component, executes the hydrological analysis using meteorological data. The unified management system can provide the latest information, such as image data, lists and items of facilities, and items of reforming and rebuilding etc., of the facilities to the manager. At the same time, this system can manage hydrological and meteorological data in realtime.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.969-982
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• 2008

As hydrological models have been progressively developed, they are recognized as appropriate tools to manage water resources. Especially, the need to evaluate the effects of landuse and climate change on hydrological phenomena has been increased, which requires powerful validation methods for the hydrological models to be employed. As measured streamflow data at many locations may not be available, or include significant errors in application of hydrological models, streamflow data simulated by models only might be used to conduct hydrological analysis. In many cases, reducing errors in model simulations requires a powerful model validation method. In this research, we demonstrated a validation methodology of SWAT model using observed flow in two basins with different physical characteristics. First, we selected two basins, Gap-cheon basin and Yongdam basin located in the Guem River Basin, showing different hydrological characteristics. Next, the methodology developed to estimate parameter values for the Gap-cheon basin was applied for estimating those for the Yongdam basin without calibration a priori, and sought for validation of the SWAT. Application result with SWAT for Yongdam basin showed $R_{eff}$ ranging from 0.49 to 0.85, and $R^{2}$ from 0.49 to 0.84. As well, comparison of predicted flow and measured flow in each subbasin showed reasonable agreement. Furthermore, the model reproduced the whole trends of measured total flow and low flow, though peak flows were rather underestimated. The results of this study suggest that SWAT can be applied for predicting effects of future climate and landuse changes on flow variability in river basins. However, additional studies are recommended to further verify the validity of the mixed method in other river basins.

• The Journal of Engineering Geology
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• v.10 no.3
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• pp.263-272
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• 2000

The main objective of this study is to simulate the rainfall-runoff relationship of the Ohwon rivet basin. For the this study, we used GIS technique and HMS(Hydrological Modeling System). In this study, watershed itself and geometric factors of watershed are extracted from DEM by using a GIS technique. The scanned data of topographical map with scale of 1:50,000 in the Ohwon river basin is used to this study and it is converted to DEM data. The parameters of Hydrological Modeling System as watershed area(A), river length, SCS Curve Number(CN) etc. are extracted by using the GIS technique in the Ohwon Basin. Extracted parameters are applied to the Hydrological Model System, then the paramenters optimized by the observed data and rainfall data. Then, the optimized parameters and Hydrological Modeling System are applied to the study area for the simulation of rainfall-runoff relationship. With the resultn of this study, GIS technique is useful to the extraction of watershed characteristics factors and Hydrological Modeling System is successful to the simulation of rainfall-runoff relationship.

• Journal of the Korean Association of Geographic Information Studies
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• v.2 no.3
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• pp.46-59
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• 1999

Remote sensing provides informations on the changes of the hydrological states and variables over with the temporal and spatial distribution to monitor hydrological conditions and changes for large area. Especially, it can extract a spatial distribution of hydrological parameters such as surface albedo, vegetation informations, and surface temperature to effectively manage water resources of the watershed. In this study, we analyzed the characteristic of temporal and spatial changes in surface hydrological parameters which is necessary to identify the spatial distribution of water resources. 5 Landsat TM data of 1995 which is collected for Bochong-chon watershed, located in the upper stream of Keum River, were used to estimate characteristics on the change of hydrological parameters and atmospheric correction was carried out using COST model. The study showed that the difference of the albedo by the land cover was very sensitive depending upon the change of sun elevation and the amount of water in the soil. The difference between the surface temperature analysis and the measured air temperature was from $2.5^{\circ}C$ to $3.86^{\circ}C$.