• Journal of Korea Water Resources Association
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• v.40 no.7
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• pp.523-532
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• 2007

It has been operated since 1974, recently, the flood forecasting and warning system is applied in almost all the rivers in Korea, and the Storage Function Method (SFM) is used for flood routing. The SFM which was presented by Toshimitsu Kimura (1961) routes floods in channels and basins with the storage function as the basic equation. A watershed is divided into two zone, runoff and percolation area and runoff from runoff area is occurred when cumulated rainfall is not exceed saturation point, but exceed runoff is occurred from percolation area, too. Runoff area is given and not changed, runoff ratio is constant. In routing Process, runoff from runoff and percolation area is routed seperately with nonlinear conceptual reservoir having the same characteristics and it is unreasonable assumption. A modified SFM is proposed with storage function and continuity equation which has no assumption for routing process and effective rainfall is calculated by SCS Method. For Wi-stream, comparison of Kimura and the modified SFM is conducted, and it could be seen that the modified SFM is more improvable and applicable method easily by reducing the parameters.

• IE interfaces
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• v.23 no.4
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• pp.311-318
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• 2010

In the daily multi-reservoir operating problem, monthly storage targets can be used as principal operational guidelines. In this study, we tested the use of a simple back-propagation Artificial Neural Network (ANN) model to derive monthly storage guideline for daily Coordinated Multi-reservoir Operating Model (CoMOM) of the Han-River basin. This approach is based on the belief that the optimum solution of the daily CoMOM has a good performance, and the ANN model trained with the results of daily CoMOM would produce effective monthly operating guidelines. The optimum results of daily CoMOM is used as the training set for the back-propagation ANN model, which is designed to derive monthly reservoir storage targets in the basin. For the input patterns of the ANN model, we adopted the ratios of initial storage of each dam to the storage of Paldang dam, ratios of monthly expected inflow of each dam to the total inflow of the whole basin, ratios of monthly demand at each dam to the total demand of the whole basin, ratio of total storage of the whole basin to the active storage of Paldang dam, and the ratio of total inflow of the whole basin to the active storage of the whole basin. And the output pattern of ANN model is the optimal final storages that are generated by the daily CoMOM. Then, we analyzed the performance of the ANN model by using a real-time simulation procedure for the multi-reservoir system of the Han-river basin, assuming that historical inflows from October 1st, 2004 to June 30th, 2007 (except July, August, September) were occurred. The simulation results showed that by utilizing the monthly storage target provided by the ANN model, we could reduce the spillages, increase hydropower generation, and secure more water at the end of the planning horizon compared to the historical records.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.2
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• pp.75-82
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• 2008

There are almost 18,000 dams including about 1,200 large dams in Korea. The large dams are well operated and maintained by KWATER(Korea Water Resource Corporation), KRC(Korea Rural Community & Agriculture Corporation) and KHNP(Korea Hydro & Nuclear Power Co., Ltd.). Several research reports concern with the safety of these large dams are presented but there is no paper concerned with small dams which has diversion tunnel through the dam body. The purpose of this study is to show the common defects of small dams according to various cases of degradation of dams and the repair and retrofit methods which applied to the damaged dams. And this study performed resistivity survey to evaluate the effect of retrofitting dam. Also, this study tries to present the solution which concerned with these common defects in maintenance and design steps.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.743-746
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• 2008

Recently, due to the effect of global warming and extreme rainfall, the magnitude of flood disaster and the frequency of flood is rapidly increasing. In order to mitigate the damage of human and property from this kind of meteorological phenomenon and manage water resources scientifically, effective operation of dam and reservoir is very important. In case of Andong dam which was not performed a flood control function needs to develop new types of dam safety management measure because of recent extraordinary flood by typhoons. In case of Andong dam and Imha dam, I am using HEC-5 model in order to apply reservoir simulation. In this case, complex conditions among 100-year floods , 200-year floods and PMF was used. Also, I modified the maximum outflow 3,800m3/s into 3,490m3/s and applied this modified discharge in order to secure freeboard in the downstream. In an analysis that I applied modified outflow by 100-year floods and 200-year floods to, the result showed that river didn't overflow in Andong area but some other places have relatively low freeboard. In the cases that I modified maximum outflow, results showed that freeboard of levee is larger than existed simulation. In the simulation that I applied 200-year floods and PMF to and under a condition connected with PMF, results showed overflowing the levees. Because of the difference between the frequency of dam outflow and the design flood in river, it is required to improve the existed flood plan in the downstream of Andong dam. As a result of this study, the optimal operation of reservoir systems can be proposed to mitigate the flood damage in the downstream of Andong dam and also can be used to establish the flood plans.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.1
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• pp.17-28
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• 2011

This study was performed to ascertain the possibility of securing inflows to reservoir with low ratio of watershed to paddy field areas by outside diversion weir. The case of Maengdong reservoir and Samryong diversion weir was selected. Most of inflows to Maengdong reservoir with watershed area of $7.06\;km^2$ and total storage capacity of $1,269{\times}10^4\;m^3$ are filled with intake water from outside Samryong diversion weir. Only using water storage data in Maengdong reservoir from 1991 to 2009, the range of water intake in Samryong diversion weir to Maengdong reservoir was optimized to 0.135~30 mm/d, from which water intake to Maengdong reservoir was $1,672.9{\times}10^4\;m^3$ (70.1 %) and downstream outflow to Weonnam reservoir was $714.4{\times}10^4\;m^3$ (29.9 %). The parameters of DAWAST model for reservoir inflow were determined to UMAX of 313.8 mm, LMAX 20.3 mm, FC 136.8 mm, CP 0.018, and CE 0.007. Inflows to Maengdong reservoir were $427.1{\times}10^4\;m^3$ (20.3 %) from inside watershed, and $1,672.9{\times}10^4\;m^3$ (79.7 %) from outside. Paddy irrigation water requirements were estimated to $1,549{\times}10^4\;m^3$ on annual average. Operation rule curve was drawn by using daily inflow and irrigation requirement data. By securing the amount of inflow to Maengdong reservoir to about 80 % from outside Samryong diversion weir, water supply capacity for irrigation of $1,549{\times}10^4\;m^3/yr$ was analyzed to be enough. Additional water supplies for instream flow were analyzed to $1,412\;m^3/d$ in normal reservoir operation, $36,000\;m^3/d$ in withdrawal limit operation by operation rule curve from October to March of non irrigation period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4447-4454
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• 2013

In October 2011, a commercialized 100kW class floating photovoltaic system positive plant was installed at Hapcheon dam a multi-purpose reservoir the first time ever in the nation. Floating photovoltaic system differs in water float, mooring device and underwater cable process from land photovoltaic system. As for land and building photovoltaic power generation equipments, many installation cases and skilled experiences are available, and thus installation is not difficult. However, commercial power generation floating photovoltaic system, which is attempted for the first time in the nation, requires to be designed and installed through a series of processes like technical review and verification of data by process in comparison with similar cases. The structure of floating photovoltaic system, an equipment for float photovoltaic module and other electrical equipment, is required to withstand weather environments like wind or typhoon etc and yet not affect water quality negatively, and for implementation of this system, construction efficiency and economy etc should be considered comprehensively. In this paper, the techniques of installing floating photovoltaic structure, mooring device, underwater cable, electrical equipment and remote monitoring control system are explained. The 100kW floating PV system is operating with 15% average capacity factor.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.971-971
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• 2012

4대강 살리기 사업으로 인하여 4대강에 대한 전면적인 투자와 공사가 이루어지고 있다. 4대강 사업이 마치게 되면 전국에 많은 수의 대규모 보가 설치되고 설치되어진 보는 각각의 강의 관리에 많은 영향을 미치게 될 것이다. 그러므로 이 4대강 사업으로 조성되는 13억 톤 수자원을 융 복합기술을 이용하여 감시 및 관리를 해야 할 것이다. 이를 위해서 실시간 수질 감시 및 모니터링 시스템의 개발과 그에 따른 센서들의 개발을 통하여 4대강 보 운영관리를 위한 통합관리 시스템개발(Ubiquitous River Management)이 이루어 져야 할 것이다. 그동안 계산 시간의 제약을 받아 오던 3 차원 수리동역학의 모의가 컴퓨터관련 기술의 발달에 따라 계산에 소요되는 시간이 계속 단축되고 있으며 이를 수질예측에 사용하는 연구가 활발히 진행되고 있다. 그에 따라 실시간으로 얻은 데이터를 이용하여 모델링 기법을 통해 예측을 해봄으로써 보 내부에 존재하는 여러 취수원 관리에 적용을 할 수 있을 것이다. 본 연구에는 3차원 수리동역학 모델과 수질모델을 결합한 시스템이 저수지 내의 수리특성, 유사이동 및 탁수 현상을 모의하는데 사용이 가능한지를 알아보는 것을 주목적으로 하고 있다. 본 팔당댐 모의에서는 취수구에 따른 수질변화를 모의하기 위해 3차원모델의 사용이 필요하다. 따라서 본 모의에서는 미국 환경부에서 WASP에 이용하기 위해 수정한 EFDC1(2009, USEPA에서 입수)을 사용하였다. 본 연구에서는 팔당호의 2009년의 수위, 수온, 유량 및 농도의 실측자료를 이용하여 3차원 수리 모델링을 실시하고, 수위, 유사이동 및 탁도 예측 모델링을 실시하였다. 3차원 수리동역학 모델과 취수원의 적용에 적절한 모델을 구축하기 위하여 적당한 평면격자의 개수를 선택하여 선택되어진 평면격자에서 수직격자의 층수를 조절하여 매 층마다 DYE TEST를 하였다. 이는 각각의 유입 하천에서 오염물질이라 가정하고 농도가 유입되었을 때 수리특성에 의해서 연구지역에서의 농도 변화를 파악하여 미리 예측을 하여서 그에 따라 취수원에서의 취수 관리를 가능하게 할 수 있다. 이를 위해서 평면격자에 따라서 수직 층의 개수를 5층부터 40층까지 모의를 하여서 시간 및 이동변화에 따라 알맞은 모델을 구축하였다. 또한 층수마다 Sediment 모의를 통하여 호 내의 SS의 이동을 모의하였다. 이 역시 취수원의 관리를 가능하게 할 수 있다.

• Journal of Korea Water Resources Association
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• v.50 no.8
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• pp.563-577
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• 2017

As the uncertainty of precipitation increases due to climate change, seasonal forecasting and the use of weather forecasts become essential for efficient water resources management. In this study, the categorical probabilistic long-term forecasts implemented by KMA (Korea Meteorological Administration) since June 2014 was evaluated using assessment indicators of Hit Rate, Reliability Diagram, and Relative Operating Curve (ROC) and a technique for obtaining quantitative precipitation estimates based on probabilistic forecasts was proposed. The probabilistic long-term forecasts showed its maximum predictability of 48% and the quantified precipitation estimates were closely matched with actual observations; maximum correlation coefficient (R) in predictability evaluation for 100% accurate and actual weather forecasts were 0.98 and 0.71, respectively. A precipitation quantification approach utilizing probabilistic forecasts proposed in this study is expected to enable water management considering the uncertainty of precipitation. This method is also expected to be a useful tool for supporting decision-making in the long-term planning for water resources management and reservoir operations.

• Journal of Korea Water Resources Association
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• v.37 no.10
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• pp.799-812
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• 2004

Conjunctive use of surface and ground water has drawn much attention as a promising means to solve water shortage problems. Characterized by its maximum utilization of regional resources and environmental friendliness, conjunctive use is expected to contribute to the integrated water resources management in the coming era. This paper examines the applicability of the methodology for conjunctive use developed in the companion paper (this issue). The method consists of the entire process of conjunctive use, including site assessment using analytic hierarchy process, management scenario development based on drought analysis, and evaluation of benefits obtained. Sokcho City was chosen as the study area, and the application of derived operation scenarios for surface and subsurface reservoirs revealed that water of 4.9∼7.4 million cubic meters a year can be attainable additionally. The developed methodology enables one to devise management schemes and to quantify their effectiveness, which makes the method useful for water resources planners as well as practitioners.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.397-397
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• 2017

수면증발량은 수자원 계획 및 활용에 있어 매우 중요한 요소이다. 하지만, 현재 수면증발량관측 지점은 용담댐, 안동댐뿐이다. 이중 장기간 관측 자료가 축적된 용담댐 지점을 대상으로 연도별 수면증발량 관측 자료를 비교 검토 하고자한다. 용담댐에 부착되어 있는 수면증발량계는 0.03 mm 분해능을 가지는 부력식 수위계(BYL-EV250, 대한민국)를 사용하고 있으며, 2014 년도 2 월부터 17 년 현재까지 관측을 하고 있다. 관측 자료로 보았을 때, '14년도 가장 많은 증발량이 발생된 달은 9월(102.63 mm/month), 적은 달은 2월(22.99 mm/month) 이였으며, '15, '16년는 각각 100.91 mm/month, 114.38 mm/month로 8월이 높고, 29.11 mm/month, 25.83 mm/month로 2월이 가장 적었다. 아래 표는 14~16년도 월평균 일 증발량 및 총 수면증발량을 나타낸 것이다. 월별 일평균 증발량을 비교한 결과 0.92~3.08 mm/day로 나타났으며, 5월부터 10월까지 많은 량(약 2.9 mm/day)이 증발되는 것으로 나타났다. 연도별 월평균 일 증발량은 9 월이 3.08 mm/day 로 증발량이 많고, 2 월이 0.92 mm/day로 적은 증발량의 관측이 되었다. 총 수면증발량은 8 월이 92.73 mm/month 으로 증발량이 가장 높았으며, 2 월이 25.97 mm/month 로 가장 적은 증발량이 관측되었다. 저수지 수면에서의 증발은 풍속, 수온, 대기온도, 일사량 등에 영향을 많이 받음에 따라 수온이 가장 낮은 2월에 증발량이 가장 적게 나타난 것으로 판단된다.