• 한국농공학회논문집
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• 제56권6호
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• pp.103-111
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• 2014

This study was to develop the flood analysis module (FAM) for implementation of a web-based real-time agricultural flood management system. The FAM was developed to apply for an individual watershed, including agricultural reservoir. This module calculates the flood inflow hydrograph to the reservoir using effective rainfall by NRCS-CN method and unit hydrograph calculated by Clark, SCS, and Nakayasu synthetic unit hydrograph methods, and then perform the reservoir routing by modified Puls method. It was programmed to consider the automatic reservoir operation method (AutoROM) based on flood control water level of reservoir. For a $15.7km^2$ Gyeryong watershed including $472{\times}10^4m^3$ agricultural reservoir, rainfall loss, rainfall excess, peak inflow, total inflow, maximum discharge, and maximum water level for each duration time were compared between the FAM and HEC-HMS (applied SCS and Clark unit hydrograph methods). The FAM results showed entirely consistent for all components with simulated results by HEC-HMS. It means that the applied methods to the FAM were implemented properly.

• 생태와환경
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• 제45권2호
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• pp.200-209
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• 2012

The current of the water body is very important information for the water quality management on reservoirs. It is applied to hydraulics and water quality model for simulation. In this regard, the current characteristic of water body is the basic information that can be used to predict various conditions. However, it is very slow flowing and is affected by the reservoir operations and external factors. As such, an accurate measurement of the current is a difficult problem. In order to measure the water current, we constructed a drifter. According to the result of flow survey at Yongdam reservoir, 5m and 10 m depth layer flow was investigated from the upstream to the downstream, during a flood period. Maximum flow rate of 5 m depth is 13.8 cm $sec^{-1}$ and 10 m depth shows 4 cm $sec^{-1}$, respectively. But 2m depth shows a backward flow and maximum flow rate is 4 cm $sec^{-1}$. Density currents flow plays the role of back flow in reservoirs. Flow velocity in the reservoir was measured in the range of 1~2 cm $sec^{-1}$, at normal flow season, and the flow direction were different for each survey. This phenomenon occurs because the reservoir volume is very large, compared to the inflow and outflow volume.

• 한국농공학회논문집
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• 제54권3호
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• pp.103-111
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• 2012

Works for dam heightening plan have dual purposes: flood disaster prevention by securing additional storage volume and river ecosystem conservation by supplying stream maintenance flow. Now, the dam heightening project is in progress and there are 93 dam heightened reservoir. After the dam heightening project, 2.2 hundred million ton of flood control volume in reservoirs will be secured. Thus it is necessary to evaluate the effects of the dam heightening project on watershed hydrology and stream hydraulics, and resulting flood damages. This study was aimed to assess the impact of outflow from the dam heightened reservoir group on the Whangryong river design flood. The HEC-HMS (Hydrologic Engineering Center-Hydrologic Modeling System) model was used for estimating flood discharge, while HEC-5 (Hydrologic Engineering Center-5) was used for reservoir routing. This study analysed flood reduction effect on 100yr and 200yr return periods about the before and after heightening of agricultural dams. Based on the results of this study, the reduction of flood peak discharge at downstream of the reservoir group was estimated to be about 41% and 53% for 100yr and 200yr frequencies, respectively.

• 한국물환경학회지
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• 제29권6호
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• pp.825-831
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• 2013

The Suwon stream which consists of a mountainous reach, an artificial reservoir and an urban reach provides benthic macroinvertebrates with various habitats. This study was conducted to find out the influence of reservoir sluice control and water quality on benthic macroinvertebrates community in the Suwon stream from June to August, 2011. As a result, substrate composition showed little difference between the upper site (S2) and the lower site of the reservoir (S3). At site S3, water velocity was fastest, and water temperature was lowest due to the intermediate depth discharge of the reservoir. Cheumatopsyche brevilineata which prefer fast water velocity was dominant at site S3. Some biotic indices (H', J, and R) of site S3 decreased significantly whereas Benthic Macroinvertebrate Index (BMI) showed little difference between site S2 and site S3. EPT showed a negative correlation with water temperature. The sluice control of the reservoir leaded variations of water velocity and temperature, and seemed to make the state of aquatic ecosystem worse.

• 한국환경과학회지
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• 제16권3호
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• pp.357-367
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• 2007

Recently, eutrophication or lake and reservoir has become serious problem to man who want use that water for several purpose. In order to solve the eutrophication problem, the trophic state of that eutrophic lake and reservoir should be measured properly. For the purpose of this, various method to indicate the trophic state of lake and reservoir was developed by many researchers. This research was conducted to evaluate characteristics and eutrophication of water qualitymfor small scale reservoir in Kunsan. On-site investigation to 5 reservoirs and laboratory experiment were carried out during four seasons from November, 2003 to July, 2004. Twelve items measured field ana a laboratory. Measured data was analyzed to quantitative method by multivariate approach and eutrophication index. The result is summarized as following. 1) Showing the characteristics of water quality for reservoir in Kunsan, Okgu reservoir and Oknua reservoir was exceeded 4 grades of agricultural water standard in TP, TN and COD. This means that eutrophication was gone much, therefore, water-purity control of reservoir need. While, Mije reservoir that is used to Kunsan citizens' recreation was good in water quality. But, water quality exceeded 4 grades of agricultural Dater standard sometimes. 2) As a results of correlation analysis between variables of water qualify, Interrelation between variables which is connected with eutrophication was expressed good relationship as above 6.000 in correlation coefficients. The correlation coefficient(r) between COD and chlorophyll-a, total phosphorus and chlorophyll-a, total nitrogen and chlorophyll-a were 0.750, 0.720 and 0.600 respectively. Therefore, Change of water quality can grasp according to eutrophication progress degree. 3) If do evaluate to eutrophication by quantitative method which is proposed by OECD, US-EPA and Forsberg & Ryding, in the case of chlorophyll a, Okgu, Oknua and Daewi reservoir was eutrophic state and Mije and Geumgul reservoir was mesotrophic state. But, estimation by TN and TP showed highly eutrophic state (hypereutrophic) in all reservoirs. 4) If do evaluate by eutrophication index which is Carlson's TSI, revised carlson TSI and Walker's index, in the case of chlorophyll a, TSI values of Okgu, Oknua and Daewi reservoir is eutrophic state more than 50 and Mije and Geumgul reservoir was mesotrophic state as range of $40{\sim}50$ in TSI value. But, in the case of TP as nutrients, all reservoirs showed highly eutrophic state which was exceed to 70 in TSI value. According to above results, the water quality for small scale reservoirs in Kunsan is progressing by trophic state. therefore, for continuous use as agriculture water, we had better do establishment of management plan about water quality.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.269-272
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• 2002

Turbidity currents, often develop after heavy storm events, deliver various non-point pollutants and tend to lead eutrophication, depressed dissolved oxygen, and sedimentation in reservoirs. Field observations were performed to investigate the flow regimes of turbidity currents and their impact on reservoir water quality in Daecheong Reservoir. A 2D laterally-averaged hydrodynamic and water quality model was applied to simulate the temporal and spatial distributions of turbidity in the reservoir, and evaluated by comparing with the field data.

• 한국농공학회지
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• 제37권E호
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• pp.47-54
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• 1995

Irrigation water has been mainly used for paddy rice. Irrigated paddy land tends to be recently converted to land for green house, farm house, and rural-industrial complex. Consequently, demand of water for crops, domestic & industrial, rural recreations, small-scaled hydropower, livestocks, and environment in the rural area, so called rural water, is rapidly increasing. In order to supply rural water, water in the existing irrigation reservoir could be enlarged by repairment of irrigation canal and reinforcement of irrigation reservoir, and be saved by the operation rule curve, utilization of dead water, and balanced storage management.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.202-206
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• 2001

In this study, the risk assessment of small reservoir by collapse using GIS is evaluated. Direct damage distance from collapsed reservoir is estimated by empirical USBR equations and submerged area is calculated by USBR's idea. The amount of damage by collapsed reservoir is figured out by damage assessment of National Institute for Disaster Prevention.

• 한국환경과학회지
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• 제14권11호
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• pp.995-1004
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• 2005

As a research establish reservoir safety operation for small dam systems. This study presents hydrologic analysis conducted in the Duckdong and Bomun dam watershed based on various rainfall data and increase inflow. Especially the Duckdong dam without flood control feature are widely exposed to the risk of flooding, thus it is constructed emergency gate at present. In this study reservoir routing program was simulation for basin runoff estimating using HEC-HMS model, the model simulation the reservoir condition of emergency Sate with and without. At the reservoir analysis results is the Duckdong dam average storage decrease $20\%$ with emergency gate than without emergency gate. Also, the Bomun dam is not affected by the Duckdong flood control augmentation.

• 한국환경과학회지
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• 제6권5호
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• pp.417-423
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• 1997

The objective of this study Is to supply basic data for large reservoir sedimentation research In future and make suggestions to maintain and opera능 the reservoir more of efficiently. At first, previous studios about the estimation of sediment yield rate were reviewed in Korea. And the discharge rating curves of upstream stage gauging stations and the correlation between dam Inflow and stage discharge were analyzed. With the analysis results, the spec유c sediment rate of Soyanggang dam was estimated as 608 m3/km2/yr. It was similar to that of Soyanggang dam feasibility study and 1994's field surveys of the reservoir than that of 1983's field surveys. Because the sediment rating curves were derived under the low discharge conditions, It needs to be checked under the flood conditions. However, the suggested methods such as flowrate analysis and sediment estimation will be useful to the sediment studios In future. Key words . reservoir sediment, sediment yield rate, rating curve, flowrate analysis.