• Water for future
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• v.14 no.4
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• pp.19-26
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• 1981

The auto-and cross-correlation function, power spectrum, coherence function and Markov model are applied to investigate the statistical characteristics of discharge and each factor of water quality and the interrelation-ship between the variation of discharge and water quality factors. The analysis of discharge, dissolved oxygen and electric conductivity, which were only obtainable data at the Indogyo gagining station in the downstream of the Han River, clearly showed that they hace distinct period of 12 months and three different periods of 6, 4 and 3 months weaker than the former. The cross-correlation between the discharge and water quality(DO, COND) is rather weak and the crosscorrelation function has its peak at lag one. It is considered therefrom that the variation of discharge behaves on water quality facotrs with one day's difference. In the examination of linear regression model for the serial generation and predictive measures, discharge series is fit to first and second order Markov model and DO, COND to first order Markov model.

• Water for future
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• v.29 no.1
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• pp.163-179
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• 1996

Flood flow characteristics of the Han River (from Goan to Indo Bridge) are analyzed using 1-dimensional St. Venant equations. NETWORK, a finite difference model, is used to calculate each term (local acceleration term, convective acceleration term, pressure force term, gravity force term, and friction force term) of the momentum equation and to analyze the flow characteristics. By the result of the study, as the general characteristics of flow in a channel that acceleration terms are very small and the other three terms are much greater is presented, three terms(pressure force term, gravity force term, friction force term) are to be main terms which decide the characteristics of flow. Specially in this region the acceleration term is noted so large that it cannot be ignored according to the shape of hydrograph and the region.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.63-70
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• 1989

The numerical model for the flood routing at the downstream of the Han river is established by using Preissmann's four-point linear implicit finite difference scheme. It is approved by the applications of this model to the selected four flood events that the released discharge hydrograph at Paldang dam which is used as upstream boundary condition of this model is better than the discharge hydrograph at Goan site. Such a result is due to the poor reliability of rating curve at Goan site. As its alternative, new rating curve at Goan site is proposed by means of applications of this numerical flood routing model. The variations of Manning's roughness coefficient may be negligible in view of the flood routing results.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.341-350
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• 2000

The objectives of this study are to develop a state-space form of stochastic dynamic storage function routing model and to test the model performance for real-time flow forecast. The selected study area is the main Han River starting from Paldang Dam site to Indogyo station and the 13 flood events occurred from 1987 to 1998 are selected for computing model parameters and testing the model performance. It was shown that the optimal model parameters are quite different depending on Hood events, but the values used on field work also give reasonable results in this study area. It is also obvious that the model performance from the stochastic-dynamic model developed in this study gives more accurate and reliable results than that from the existing deterministic model. Analysis for allowable forecast lead time leads that under the current time step the reasonable predicted downstream flows in 5 hours time advance are obtained from the stochastic dynamic model on relatively less lateral inflow event in the study area.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1058-1062
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• 2010

최근 하천정비 사업은 하천의 치수, 이수적인 기능뿐만 아니라 자연 친화적인 기능을 고려하여 하천을 조성하기 위한 노력들을 많이 하고 있다. 그 결과 기존 콘크리트 호안을 자연형 호안으로 바뀌어 생태계 복원 및 접근성을 높이고, 직선형 하도를 사행하는 자연형 하도로 바꾸는 등의 다양한 하천복원 사업들을 실시하고 있다. 하지만 하천복원에 따른 유지관리를 위한 하천복원공법들에 대한 모니터링과 복원사업에 대한 효과 분석이 제대로 이루어지지 못하고 있다. 따라서 하천복원 전, 후에 대한 모니터링과 평가를 위한 연구가 필요하다. 이에 본 연구에서는 2001년에 시작하여 2006년 12월에 복원 사업이 완료된 오산천 하천환경 정비사업에 적용된 복원 공법들의 수리학적 모니터링을 통해 복원 후의 효과 및 문제점들을 평가하였다. 우선 수리학적 모니터링의 일반적인 사항으로 강우량 및 홍수량 측정, 하상변동 분석, 하상재료 분석 그리고 항공영상 분석을 수행하였다. 또한 복원 공법에 대한 수리학적 모니터링은 호안의 수리학적 안정성 평가, 어도의 기능 평가, 저수로내에 설치된 인도교 주변과 목교의 수리학적 영향을 분석하였다. 모니터링 결과 복원 후 일부 목교 주변과 자연형 호안 중 일부는 침식되었으며, 하중도 하류부에는 퇴적이 발생한 것을 확인하였다. 금곡취수보에 설치된 어도는 자체안전성에는 문제가 없었으나, 어류 소상을 위한 기능을 다하지 못하는 것으로 확인되었다. 또한 상류 하천정비로 인해 하류에 퇴적이 많이 되어 있는 것을 확인하였다. 이와 같은 적용 공법별 수리학적 모니터링 결과는 복원 공법에 대한 모니터링 및 평가를 위한 지침서 작성을 위한 기초자료로 사용될 것으로 기대된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.3
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• pp.61-71
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• 1988

The stage-discharge relation curve(rating curve) is the basic formula in hydrologic analysis. It plays an important role in converting to the discharge from available flood water level data including the daily mean stage. However, the river induces a cross section change at the gauging station because of the composed material of the river bed and three processes of the stream flow; i.e., erosion, transportation, and sedimentation. Rating curve has to be revised according to the temporal variation of the river bed due to the those factors. In this study, the basic rating curve is developed with respect to the current river bed to convert the existing rating curves and also to seize the hydraulic and geometric characteristics for the temporal variation of the river bed, relationships among the basic rating curve and the existing rating curves, water level, cross sectional area, and flow velocity are analyzed. Indogyo station, which is not only the key station of the Han river but also greatly changed the river bed after completion of the Han river development plan during the year 1983 to 1986, was chosen for the study. In this study, the river bed is assumed in a dynamic equilibrium condition. The basic rating curve is developed using hydrologic data of the physical year of 1987. For a given discharge, relationships for conversion of previous data, stage and velocity, the current one are formulated. To verify the usefulness of the relationships, stage-cross sectional area and stage velocity formula are also derived. Both hydrologic method using continuity equation and statistical method by the rating curve are compared and checked, then the validation of the both are positively shown.

• Journal of Korea Water Resources Association
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• v.35 no.2
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• pp.161-171
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• 2002

It has been known that the accurate estimates of 2-dimensional water quality model parameters are difficult for non-experts due to the complexity of theoretical background and input requirement and complicated inter-relationship between model Parameters. The main goal of this study is to Provide expert system for the optimal estimation of water quality model parameters, which is based on the development of chaining mechanism according to the sensitivity analysis of model parameter interactions and GUI interface system on ArcView Avenue. The selected study area is the 35.3- km main Han river starting from Paldang Dam site to the Point of Indo bridge and the tributary inflows including pollutant data are used for the system application and validation. The estimated main model parameters are 0.367 for transverse dispersion coefficient, 0.074 for and 0.162 for. It also shows that the simulated water quality constituents such as DO and BOD based on the estimated model parameters are well agreed with the observed ones. It can be concluded that the developed GIS-based expert system for water quality model parameter estimation and graphical representation of water quality analysis is useful for the scientific water quality management.