• 한국농공학회논문집
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• 제57권4호
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• pp.85-99
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• 2015

It is urgent to redevelop the superannuated reservoir levee through the levee raising for countermeasure to climate change and improvement of storage capacity of reservoir. However, low compaction degree of the raised reservoir levee owing to poor construction condition leads to degradation of the stability of the reservoir levee on seepage and earthquake. In this study, seepage and seismic behavior of raised reservoir levee with low compaction degree was evaluated through numerical simulation. From the simulated results, water level raising possibly induces crack and/or sinkhole on the surface of the poorly-compacted raised reservoir levee owing to the increase of the subsidences at the crown and the front side of that. In addition, relatively larger displacement and acceleration response at the front side of raised reservoir levee in seismic condition may degrade overall stability of reservoir levee. Therefore, reasonable construction management for the compaction of the raised reservoir levee is required for ensuring long-term stability on seepage and earthquake.

• 한국농공학회논문집
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• 제54권2호
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• pp.37-46
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• 2012

The change of rainfall pattern and hydrologic factors due to climate change increases the occurrence probability of agricultural reservoir water shortage. Water supply assessment of reservoir is usually performed current reservoir level compared to historical water levels or the simulation of reservoir operation based on the water budget analysis. Since each reservoir has the native property for watershed, irrigation district and irrigation water requirement, it is necessary to improve the assessment methods of agricultural reservoir water capability about water resources system. This study proposed a practical methods that water supply vulnerability assessment for an agricultural reservoir based on a concept of probabilistic reliability. The vulnerability assessment of water supply is calculated from probability distribution of water demand condition and water supply condition that influences on water resources management and reservoir operations. The water supply vulnerability indices are estimated to evaluate the performance of water supply on agricultural reservoir system, and thus it is recommended a more objective method to evaluate water supply reliability.

• 한국환경과학회지
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• 제17권7호
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• pp.733-741
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• 2008

The object of this study is the safety insurance of the dam to provide for the extraordinary flood. The safety insurance of the reservoir was taken by the preparatory discharge using the temporary division tunnel used during the reservoir construction. In this study, the Sungju reservoir was simulated. The existing discharge facilities of the intake tower of the Sungju reservoir could nat have influence on the flood control. When the Sungju reservoir operated to begin preparatory discharge for 48 hrs by the temporary diversion tunnel that have discharge of an 20-years frequency, the water level was lowered about 20 cm. When the Sungju reservoir operated to begin the continuous discharge after the preparatory discharge, the water level was lowered over 1m but the downstream at risk was caused by the resulted. If it is possible to operate to begin the preparatory discharge of the reservoir for 24 hrs by the temporary diversion tunnel, that will improve the flood control faculty of the reservoir without other hydraulic structure and safety of the Sungju reservoir will be higher.

• 한국환경과학회지
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• 제20권9호
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• pp.1125-1140
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• 2011

According to previous research on evaluating vegetative value of wetland and RAM evaluation targeting the man-made wetland in Gunsan, Gunsan Reservoir and Gongchang Reservoir had been found to have satisfactory results while Anjeong Reservoir and Changan Reservoir had been found to have unsatisfactory results. Aimed at those reservoirs, a vegetation survey was conducted to analyze differences in terms of flora and growth habit. As for the flora, Gunsan Reservoir ranked first with 433 kinds of plants, followed by Gongchang Reservoir with 306, Changan Reservoir with 176 and Anjeong Reservoir with 167. As for specific plant species by floristic region, it was identified that Gunsan Reservoir had 18 species, larger than other wetlands and also, it had more species of naturalized plants than others. This phenomenon is related to various wetland environments resulted from wider area of Gunsan Reservoir. In the case of dormancy form, hemicryptophytes were mainly distributed in Gunsan Reservoir and Gongchang Reservoir while annual plants were mainly distributed in Anjeong Reservoir and Changan Reservoir with heavy disturbance.

• 대한공간정보학회지
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• 제24권3호
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• pp.93-101
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• 2016

용수공급이나 수질관리 등과 같은 저수지 운영을 위해서는 최신의 수위별 저수면적과 저수량을 평가해야 한다. 본 연구에서는 괴연저수지를 대상으로 UAV 촬영 및 GCP 측량을 통해 정사영상과 DSM 자료를 구축하였으며, 저수지 영역에 대한 TIN 데이터모델을 구축함으로써 실제 저수구간인 149~156 EL.m에 대한 수위별 저수면적과 저수량을 계산할 수 있었다. 또한 수위별 저수면적과 저수량 자료에 대해 다양한 함수식을 적용한 결과, 수위별 저수면적은 4차 다항식을 적용한 곡선식의 결정계수가 0.97로 가장 높게 나타났으며 수위별 저수량은 2차 다항식을 적용한 곡선식의 결정계수가 0.99로 가장 높게 나타남을 알 수 있었다. 이와 같이 UAV 사진측량을 통해 저수면적과 저수량 곡선식을 산정함으로서 효율적인 저수지 관리가 가능할 것으로 판단된다.

• 한국관개배수논문집
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• 제17권2호
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• pp.57-70
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• 2010

This study was performed to analyze the affect of water supply capacity followed by allocating flood control volume in heightening reservoir, of which Baekgog reservoir was selected as a case study in here. Baekgog reservoir is located in Jincheon county, Chungbuk province, of which full water level will be heightened from EL. 100. 1m to EL. 102.1m, and total storage from 21.75M $m^3$ to 26.67M $m^3$. Flood inflow with 200year frequency was estimated to 997 $m^3$/s in peak flow and 22.54M $m^3$ in total volume. Reservoir flood routing was conducted to determine flood limited water levels, which was determined to have scenarios such as EL 97-98-99m in periods of 6.21.-7.20., 7.21.-8.20., and 8.21.-9.20., respectively, EL 97-97-97m, EL 98-98-98m in present reservoir, and EL 99-100-101m, EL 99-99-99m, and EL 100-100-100m in heightened reservoir. Reservoir inflow was simulated by DAWAST model. Annual paddy irrigation requirement was estimated to 33.19M $m^3$ to 2,975ha. Instream flow was allocated to 0.14mm/d from October to April. Operation rule curve was drawn using inflow, irrigation and instream flow requirements data. In case of withdrawal limit reservoir operation using operation rule curve, reduction rates of annual irrigation supply before and after flood control by reservoir were 2.0~4.3% in present size and 1.5~3.6% in heightened size. Reliability on water supply was decreased from 77.3% to 63.6~68.2% in present size and from 81.6% to 72.7~79.5% in heightened size. And reduction rates of water storage at the end of year before and after flood control by reservoir were 7.3~16.5% in present size and 7.7~16.9% in heightened size. But water supplies were done without any water deficiency through withdrawal limit reservoir operation in spite of low flood regulating water level.

• 한국농공학회논문집
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• 제49권4호
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• pp.3-12
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• 2007

The purpose of this paper is to analyze the relationship between meteorological factors and agricultural reservoir storage, and predict the reservoir storage by multiple regression equation selected by high correlated meteorological factors. Two agricultural reservoirs (Geumgwang and Gosam) located in the upsteam of Gongdo water level gauging station of Anseong-cheon watershed were selected. Monthly reservoir storage data and meteorological data in Suwon weather station of 21 years (1985-2005) were collected. Three cases of correlation (case 1: yearly mean, case 2: seasonal mean dividing a year into 3 periods, and case 3: lagging the reservoir storage from 1 month to 3 months under the condition of case 2) were examined using 8 meteorological factors (precipitation, mean/maximum/minimum temperature, relative humidity, sunshine hour, wind velocity and evaporation). From the correlation analysis, 4 high correlated meteorological factors were selected, and multiple regression was executed for each case. The determination coefficient ($R^{2}$) of predicted reservoir storage for case 1 showed 0.45 and 0.49 for Geumgwang and Gosam reservoir respectively. The predicted reservoir storage for case 2 showed the highest $R^{2}$ of 0.46 and 0.56 respectively in the period of April to June. The predicted reservoir storage for 1 month lag of case 3 showed the $R^{2}$ of 0.68 and 0.85 respectively for the period of April to June. The results showed that the status of agricultural reservoir storage could be expressed with couple of meteorological factors. The prediction enhanced when the storage data are divided into periods rather than yearly mean and especially from the beginning time of paddy irrigation (April) to high decrease of reservoir storage (June) before Jangma.

• 한국농공학회논문집
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• 제53권1호
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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.

• 한국농공학회논문집
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• 제65권5호
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• pp.37-49
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• 2023

The drought risk has been increasing recently due to climate change causing the extreme climate to be more frequent. In order to supply agricultural water stably under drought, it is necessary to operate an agricultural reservoir in response to drought. To this end, it is crucial to establish appropriate drought response operation rules considering weather conditions and reservoir status. In the reservoir operation simulation, the supply amount differs from the actual reservoir supply for many reasons, including maintaining water levels for supply and accommodating farmers' requests. So, for a more realistic reservoir operation simulation, it is necessary to reflect the reservoir operation rules of the actual water management site. Therefore, in this study, through a survey, the standards for limitation of agricultural water supply applied to agricultural reservoirs in Korea were investigated, and the criteria for drought response reservoir operation (DRO) were established based on the survey. Then, the DRO was applied to the irrigation period for nine subject reservoirs. The applicability was evaluated by comparing the DRO result to the operation result of HOMWRS (Hydrological Operation Model for Water Resources System). The reservoir drought index, storage rate, and daily supply were compared for evaluation. From the result, DRO showed more stable operation results in most cases against drought as it has fewer days of water supply limitation and a somewhat reservoir storage rate which can be utilized for prolonged drought.

• 한국습지학회지
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• 제3권1호
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• pp.49-59
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• 2001

The objective of this study is to provide the results of frequency analysis for Dong-eup reservoir, in which the environmental and ecological roles in addition to the water supply and flood control capacity of the reservoir are increased rapidly. The suggested results are the frequency analysis of annual maximum rainfall data based on eight different rainfall duration data at Masan and Milyang raingauge stations. We also provide the probabilistic inflows from subbasins and evaluate the stage increases of the reservoir. As results, the 24-hour and 100-year return period rainfall is 291.8 mm and consequently inflows are 361.79 cms for Junam, 192.57 for Sannam and 408.28 for Dongpan reservoirs. The 24-hour and 100-year return period reservoir stages are expected as 5.08 m, 5.51 m and 6.89 m depending on the initial reservoir stage. The suggested results of frequency analysis of rainfalls, inflows and reservoir stages in this study will be useful for the scientific and systematic management of the reservoir.