• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.117-129
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• 1993

This study was conducted to get reasonable and abundant hydrological time series of monthly flows simulated by a best fitting stochastic simulation model for the establishment of rational design and the rationalization of management for agricultural hydraulic structures including reservoirs. Comparative analysis carried out for both statistical characteristics and synthetic monthly flows simulated by the multi-season first order Markov model based on Gamma distribution which is confirmed as good one in the first report of this study and by Harmonic synthetic model analyzed in this report for the six watersheds of Yeong San and Seom Jin river systems. 1.Arithmetic mean values of synthetic monthly flows simulated by Gamma distribution are much closer to the results of the observed data than those of Harmonic synthetic model in the applied watersheds. 2.In comparison with the coefficients of variation, index of fluctuation for monthly flows simulated by two kinds of synthetic models, those based on Gamma distribution are appeared closer to the observed data than those of Harmonic synthetic model both in Yeong San and Seom Jin river systems. 3.It was found that synthetic monthly flows based on Gamma distribution are considered to give better results than those of Harmonic synthetic model in the applied watersheds. 4.Continuation studies by comparison with other simulation techniques are to be desired for getting reasonable generation technique of synthetic monthly flows for the various river systems in Korea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.231-234
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• 2007

This study proposes a Web GUI system using MGIS-based three-dimensional data models and hydrodynamic model. The study of Web GUI (Graphic User Information) system based on the MGIS (Marine Geographic Information System) is mainly performed on effective methodologies which transform real world data to computing world data. Finally, we design a Seomjin River Estuary Web GUI system integrating above data models. It must adds more ecological information and the various service item for approach more easily in order to user.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.124-143
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• 2010

Cofferdam is a temporary levee or dam structure built by using sheet pile or earth materials to prevent water infiltration during construction work of bridge, dam, harbour dock, or hydraulic structures in the river. In this regard, it is required to secure cutoff ability for dry work and workability for rapid installation and removal of the temporary dam or levee structures. In this paper, case studies for design and construction of cofferdam were performed, and water diversion method was briefed with some examples of cofferdam type as well. For the case study details of design and construction were reviewed based on cofferdams under construction related to 16 submerged weirs of "The 4-river restoration project" and dam type cofferdam respectively. From the review, it was known that the method for changing the water flow is selected based on the data from geological and geo-hydraulic site investigation in order to mitigate environmental effects by making sure if the design cross-sectional area of flow and maximum working days are sufficiently guaranteed. Finally, the primary findings and main conclusion derived are summarized that determination of applicable type of cofferdam should be checked by case study and meet design requirements such as water inflow control, constructability.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.737-742
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• 2009

This research intends to clarify the engineering characteristics of compression index which plays the most important role in the calculation of consolidation settlement, based on the survey of the clay in the estuary of Nakdong River. In addition, it will analyze the parameters of soil and the correlation between the parameters and the existing relation, especially the correlation with compression index, through which it will propose a proper relation for the parameters of clay in this area. As a result of the study, the relation between the settlement and the compression rate using compression index showed 13% settlement error on the average. It is judged that this number can be used for forecasting the consolidation characteristics and the settlement for brief (preliminary) design when the difference between the execution settlement and the measuring settlement is regarded to be 15%.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.770-774
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• 2006

The determination of feasible design flood is the most important to control flood damage in river management. Model parameters should be calibrated using observed discharge but due to deficiency of observed data the parameters have been adopted by engineer's empirical sense. Storage coefficient in the Clark unit hydrograph method mainly affects magnitude of peak flood. This study is to estimate the storage coefficients based on the observed rainfall-runoff events at the four stage stations in the Hantan river basin. Model calibration is the process of adjusting model parameter values until model results match historical data. An objective function which is the percent difference between the observed and computed peak flows is available for measuring the goodness-of-fit between computed and observed hydrographs. By sensitivity analysis for the storage coefficient, it has been shown that the storage coefficients affect the peak flows. The Clark parameters adopted in the River Rectification Basic Plan have been estimated through an iterative process designed to produce a hydrograph with the peak flow.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.141-150
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• 1992

In this study, six gaging stations(T/M bureau) in the Han River basin were selected for flood frequency analysis and was carried out frequency analysis by POT(peaks Over a Threshold) model where existing flood data of short record length are available. Frequency and magnitudes of each station floods in the river basins were estimated by POT model based on statistical method, and also were compared with standard errors to verify applicability of the estimates by POT model. Furthermore, in order to evaluate for the adequate design flood which is needed for the design of the hydrologic structures in the ungaged watersheds, it is considered to be possible to develop the statistical regionalized model by regional frequency analysis.

• Water for future
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• v.29 no.2
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• pp.167-178
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• 1996

In designing automatic water quality monitoring networks for a river basin, determination of measurement locations and items is critical to the effectiveness of the total system. In this paper we studied how to decide these two design factors when a monitoring network is designed for the purposse of water quality surveillance and emergency alarm. For measurement locations, candidate sites are chosen based on the intake amount for water supply and the point sources of contamination. Then, detailed locations are decided according to the contaminant flow distance. As for measurement items, characteristics and the accident history of water pollution in the basin must be taken into account. Considering economic aspects, we proposed a two-stage measurement plan: basic components for all locations and selective ones variable for different locations. Proposed methodology is demonstrated through a case study for Nak-dong River Basin.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.542-550
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• 2017

The estimations of flow characteristics and river-bed erosion or sedimentation are very important for hydraulic structure design, floodplain management, and especially, river management. The objective of the study is therefore to estimate the change of flow characteristics and river-bed change due to a hydraulic structure construction. With 11.65 km study area of the Geum River which are located in downstream of Daecheong Dam, flow characteristics and river-bed change were estimated based on the RMA2 and SED2D model. As the result of the study, the increase of river-bed sedimentation in upstream and river-bed erosion in downstream were occurred by the construction of hydraulic structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.294-302
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• 2020

In a genetic algorithm, computer simulations are performed based on the natural evolution process of life, such as selection, crossover, and mutation. The genetic algorithm searches the approximate optimal solution by the parallel arrangement of Schema, which has a short definition length, low order, and high adaptability. This study examined the possibility of improving the efficiency of the optimal solution by considering the characteristics of the building block hypothesis, which are one of the key operating principles of a genetic algorithm. This study evaluated the efficiency of the optimization results according to the gene sequence for the implementation in solving problems. The optimal design problem of the water pipe was selected, and the genetic arrangement order reflected the engineering specificity by dividing into the existing, the network topology-based, and the flowrate-based arrangement. The optimization results with a flowrate-based arrangement were, on average, approximately 2-3% better than the other batches. This means that to increase the efficiency of the actual engineering optimization problem, a methodology that utilizes clear prior knowledge (such as hydraulic properties) to prevent such excellent solution characteristics from disappearing is essential. The proposed method will be considered as a tool to improve the efficiency of large-scale water supply network optimization in the future.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.1
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• pp.173-184
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• 2014

Riparian areas are significant functional grounds for inhabiting ecological system on the river such as the self-regulation of the water quality and the foundation of important corridors. For such functional device to operate, consecutive land purchase scheme that prioritizes targeted areas with high pollutant load rate imposes sustainable development of the ecological riparian belt. The purpose of this study is focused on measuring the methodology for selecting land purchse order before establishing riparian belt in accordance with pollution loading estimation and the basin approach. The Yeongsan and Seomjin river which includes targeted areas of the land purchase have been classified into the large-medium-small(standard basin) influence areas based on their catchment rage, which than sub-divided the research area of Juam lake by 38 small basins and 223 units. Small basins with the high pollution load rates have been assessed as the first prioritized targets. For the second priority, the condition of the point pollutant sources, original area of the targets, original restored area were concerned. The final decision of the land purchase order targeted only those within 50 meter range from the basin. To validate the accumulated data, the on-site investigation went along the targeted zones, which the result shows that all prioritized areas included both point and non-point pollutant sources, and had not a small originally restored areas.