• Journal of Korea Water Resources Association
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• v.37 no.5
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• pp.353-361
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• 2004

Effective storage in agricultural reservoir has been determined through the reservoir simulation operation based on the water budget analysis. Since each watershed has the native property for runoff, considering the runoff yielding from the basin is feasible to the determination of reservoir effective storage. In this study the stochastic linear programming model considering mainly runoff from watershed has been also formulated to analyze the effective storage of the exiting reservoir. The linear decision rule coupled with chance-constrained model in the linear programming model contributes to reduce the size of linear program model without considering the period of analysis. The Geum-Gang reservoir located in Ansung have been adopted to evaluate the effective storage. It has been shown that the effective storage based on the linear programming model is greater than that based on the water budget analysis. It has been also desired that once the effective storage is obtained through the linear programming model, operation of the reservoir should be performed to check the designed capacity.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.59-68
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• 2005

The rainfall-runoff potential of Jangseong reservoir watershed was studied based on SCS (Soil Conservation Service, which is now the NRCS, Natural Resources Conservation Service, USDA) runoff curve number (CN) technique. Precipitation and reservoir operation data had been collected. The rainfall-runoff pairs from the watershed for ten years was estimated using reservoir water balance analysis using reservoir operation records. The maximum retention, S, for each storm event from rainfall-runoff pair was estimated for selected storm events. The estimated S values were arranged in descending order, then its probability distribution was determined as log-normal distribution, and associated CNs were found about probability levels of Pr=0.1, 0.5, and 0.9, respectively. A subwatershed that has the similar portions of land use categories to the whole watershed of Jangseong reservoir was selected and hydrologic monitoring was conducted. CNs for subwatershed were determined using observed data. CNs determined from observed rainfall-runoff data and reservoir water balance analysis were compared to the suggested CNs by the method of SCS-NEH4. The $CN_{II}$ measured and estimated from water balance analysis in this study were 78.0 and 78.1, respectively. However, the $CN_{II}$, which was determined based on hydrologic soil group, land use, was 67.2 indicating that actual runoff potential of Jangseong reservoir watershed is higher than that evaluated by SCS-NEH4 method. The results showed that watershed runoff potential for large scale agricultural reservoirs needs to be examined for efficient management of water resources and flood prevention.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.869-877
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• 2015

Freshwater may be injected into aquifers to combat sea water intrusion in groundwater or to store water for later retrieval. For these cases to achieve the desired goal groundwater modeling is commonly used to determine locations and rates of injection wells. When these wells are connected to a pipe network, a flow control valve is installed for each well to regulate the injection rate. When a valve opening is modified, pressure changes in the entire pipe network and thereby changes flow rates in other wells. Therefore, desired valve openings must be determined for all injection wells. The pipe flow analysis allows estimation of the minimum pump power in addition to valve openings. Methods are developed to identify valve openings for multiple wells and the minimum pump power. The methodology developed in this work can contribute to precise operation of multiple injection wells.

• Water for future
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• v.29 no.2
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• pp.209-219
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• 1996

The existing gate operation rule of Paldang hydroelectric plant has been used since the construction of the dam in 1973 except partial modification due to the construction of Chungju multipurpose dam in 1985. The water level near the downstream of Paldang dam has been lowered about 3 m because of the channel maintenance of Han River development project. Thus, the discharge estimation formula based on the submerged orifice type spillway has to be re-evaluated by considering various patterns of the gate operation rules and lowered channel bed. In this study, three types of gate openings were tested to select the proper gate operation rules through the hydraulic model test for various discharges and opening heights. Also, the numerical analysis has been performed to simulate the flow patterns of downstream. As a result, the gate operation rule, which opens 5 gates each time from the left side, was selected as the proper gate operation rule of Paldang dam.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.1
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• pp.51-61
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• 2011

A project constructing sewerage facilities in 9 upstream areas of 7 multi-purpose dams will have been completed by 2011. After all constructing and retrofitting of the new and the existing sewerage facilities, integrated management system with operation and control functions for the each levels of facilities will also be utilized. In this study, we studied how to compose the organization taking responsibility of the integrated management system and analysed human resources saving effect against conventional method of individual management of each sewerage facility. As a result, a method estimating the human resources in employing the integrated management among several sewerage facilities at upstream areas of dams were presented and some 23% of human resources could be saved by integrated management. Commissioning to a specialized public institute showed the highest B/C ratio of 4.5 among commissioning to local public corporations, commissioning to private corporations, and role-sharing partnership, etc.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1588-1595
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• 2005

In this study, the installation location of accelerometer and accelerograph for dam are investigated in the field to establish of emergency action against dam failure when earthquake occur and to guarantee the results of seismic stability of dams which are analysed with dynamic analysis method during 1999 to 2003 by KOWACO. By a comparative study concerning of domestic and foreign guidelines of seismic strong motion instrumentation for dams, "Guidelines of Seismic Strong-Motion Instrumentation Installation, Operation and Maintenance for Dams" is established to set up the standard of seismic strong-motion instrumentation for dam, are supervised by KOWACO There is some problems in taking a measure of stability of dams when earthquake event occur because the existing seismic strong motion instruments are operated independently. This make difficult to confirm the occurrence of seismic event. For that reason, in this study the plan of unified operation and maintenance system for strong-motion instrument for dams is designed. It will make possible real-time seismic monitoring, data transmission and receiving, giving warning for earthquake, and exchanging data with national seismic network.

• Journal of Korea Water Resources Association
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• v.31 no.2
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• pp.133-144
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• 1998

Recent development booms in urban watersheds have increased impermeable areas and brought about an increase of peak flood. Eventually, some people living in the lower area of an urban watershed, very often and seriously, have suffered form inundation. In this study, for minimization of inundation in urban watersheds, the operational criteria for pump stations are suggested. At first, ILLUDAS has been selected as a runoff model which can explain the past precipitations. Secondly the operational criteria for pump stations could be suggested by working out an operational criteria for pump stations could be suggested by working out an operation program from the relationship between pumping capacity and accumulative hydrographs, and from the Intensity-Duration-Frequency relationship.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.61-61
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• 2011

하천에서의 홍수 피해 발생을 예방하기 위한 대책은 크게 구조적인 대책과 비구조적인 대책으로 나눌 수 있다. 구조적인 대책은 댐이나 제방과 같이 하천을 중심으로 수공구조물을 설치하여 직접적인 홍수 발생을 억제하는 대책이지만, 비구조적인 대책은 무형의 체계를 통해 하천에서의 홍수발생을 억제하는 대책이다. 비구조적인 대책 가운데 대표적인 것이 홍수 예 경보인데, 한강홍수통제소에서는 1974년부터 홍수 예 경보시스템을 구축하여 운영하고 있다. 본 연구에서는 남한강 유역에 대한 홍수 방어능력 검토와 홍수 방어대책 강구에 필요한 충주 댐 수문 운영이 가능한 수리학적 홍수추적 모형을 구축하였으며, 충주댐을 중심으로 상 하류 구간에서 수위증가를 억제하기 위한 수문 운영기법을 검토하고자 하였다. 이를 위해 남한강 상류에 위치한 영월2 수위관측소로부터 팔당댐까지의 대상구간에 대해 최근 이루어진 하도측량자료를 이용하여 수리학적 모형을 구축하였다. 구축된 모형에 대해 2006년 홍수사상을 적용하여 모형의 보정을 실시하였으며, 2003년부터 2008년까지의 홍수사상을 대항으로 검증을 실시하였다. 충주댐 수문 운영은 HEC-RAS 모형 내의 E.C.G(Elevation Controlled Gate) 기법과 Rule Operation 기법을 이용하여 남한강 주요 지점에서의 홍수의 증가에 대한 억제효과를 검토하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.2089-2093
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• 2007

저수지군 연계운영 문제는 서로 상충되는 목적들이 존재하고, 다양한 평가 기준들이 존재하는 다목적 특성을 갖는 문제이다. 때문에 저수지군 연계운영 문제에 다중목적계획법이 많이 사용되고 있으나 문제의 해결을 위해 사용한 다수의 목적간의 가중치 설정에 의사결정자의 주관적요소가 반영 될 수도 있고, 설정된 가중치에 따라 결과 값이 민감하게 반응하여 의사결정자가 바람직한 가중치 설정에 어려움이 있다. 본 연구의 목적은 다중 목적 특성이 존재하는 저수지군 연계운영 문제에 다요소 의사결정기법 적용하여 바람직한 저수지별 저수 가중치를 선정하는 방법을 제안하는 것이다. 제안하는 저수 가중치 선정 절차는, 우선 GA-CoMOM (Genetic-Algorithm Coordinate Multi-reservoir Operation Model)을 통해 수계 전체 관점에서 저수량과 발전량의 상충되는 목적에 대한 파레토 최적해와 각 최적해에 해당하는 저수지별 저수 가중치를 도출한다. 다음 단계로 다요소 의사결정기법중에 하나인 수정된 거리척도 기반의 DEA 순위 선정 절차를 이용하여 도출된 최적해들의 운영 결과를 평가하여 파레토 최적해군 중에 선호해를 결정하고, 결정된 선호해의 저수지별 저수 가중치를 해당 기간의 저수 가중치로 선정한다. 설명한 선호 가중치 선정 절차를 금강 수계에 적용해 보고 저수지 연계운영에서 바람직한 가중치를 도출할 수 있음을 보인다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1423-1426
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• 2007

The goal of this research is to develop and apply the integrational model for the pan evaporation and the alfalfa reference evapotranspiration in Republic of Korea. Since the observed data of the alfalfa reference evapotranspiration using lysimeter have not been measured for a long time in Republic of Korea, PM method is used to assume and estimate the observed alfalfa reference evapotranspiration. The integrational model consists of staochastics and neural networks processes respectively. The stochastics process is applied to extend for the short-term monthly pan evaporation and alfalfa reference evapotranspiration. The extended data of the monthly pan evaporation and alfalfa reference evapotranspiration is used to evaluate for the training performance. For the neural networks process, the generalized regression neural networks model(GRNNM) is applied to evaluate for the testing performance using the observed data respectively. From this research, we evaluate the impact of the limited climatical variables on the accuracy of the integrational operation of stochastics and neural networks processes. We should, furthermore, construct the credible data of the pan evaporation and the alfalfa reference evapotranspiration, and suggest the reference data for irrigation and drainage networks system in Republic of Korea.