• Water for future
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• v.18 no.3
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• pp.225-233
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• 1985

To develop a simulation strategy of multi-reservoir operation in flood season, the single dam operations methed for the Chungju dam are investigated in the Han river basin. Thus, spillway rule curve, rigid ROM, and linear decision rules are applied for control operations, subject to the restrictions imposed by the river and the reservoir characteristics. The storage and release and control/utility efficiencies for several floods are calculated. The variation of control coefficients with respect to the return period are also examined. As the results of this comparative study, the optimal operation method can be selected in terms of the magnitude of flood. With inflow forecasting, the flood control operation can be greatly improved by variable coefficients rigid ROM and linear decision rules.

• Journal of Korean Society on Water Environment
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• v.24 no.5
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• pp.598-602
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• 2008

The Daecheong Reservoir is the largest multi-purpose reservoir in the Keum River basin. This water supply is subject to some of the most serious taste and odor (T&O) problems in the region. The intensity of T&O events increased due to eutrophication during the 1990s. In this study, the temporal occurrence of T&O in raw water from the main Daecheong Reservoir and its regulating reservoir was compared using both an instrumental method (CLSA+GC/MS) and threshold odor number (TON) test from April to December 2006. In addition, biofilms on the submerged macrophytes and rocks were analyzed for two typical T&O causing compounds, Geosmin and 2-MIB. The maximum concentration of Geosmin in the main reservoir was almost two times higher than that in the regulating reservoir. Interestingly, 2-MIB was only detected in water samples from the main reservoir. In the case of T&O causing compounds present in the biofilm on the submerged macrophytes and rocks, the regulating reservoir had lower concentrations compared to those of the main reservoir. It was found that both Geosmin and 2-MIB were detected from the biofilms much earlier than from the water samples. This result suggests that the occurrence of T&O compounds in the biofilms could be used as an early warning indicator of an imminent T&O outbreak in the water body.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.257-268
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• 2003

Daily monitoring was conducted to elucidate the changes in turbidity and distribution of particles in the turbid water of a river-type reservoir (Paltang Reservoir) from 1999 to 2001. Water turbidity and the particle distribution of turbid water were principally affected by meteorological factors particularly rainfall patterns and hydrological factors such as inflow and outflow. The mean concentration of turbidity was constant each year, with the concentration of less than 10 NTU accounting for 85%. Seasonal characteristics were remarkable, with winter and spring having < 5 NTU, autumn 5 ${\sim}$ 10 NTU, and summer > 20 NTU. Unlike hydrological changes, maximum turbidity was observed from late July to early August and continuously increased from 1999 to 2001. In particular, the maximum turbidity of reservoirs remarkably increased toward the lower part of reservoir in 2001. Discharge and turbidity increased or decreased slowly in 1999; in contrast, turbidity rapidly increased in the early rainfall period of 2000 and 2001 but later decreased as discharge increased. In the particles of turbid water, clay ingredients were more densely distributed and more dominant in all stations. Of the total particles in turbid water, clay constituted 63.9${\sim}$66.6% and silt 33.4${\sim}$36.1% to account for a combined total of 98.9 ${\sim}$ 100%. Sand made up less than 1.1%. The turbidity of river-type reservoir was also found to be mainly affected by the biomass of plankton in a non-rainfall period. During a rainfall period, however, the quantity and relative ratio of inorganic particles depending on the soil components affected turbidity.

• Journal of Korea Water Resources Association
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• v.51 no.7
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• pp.555-564
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• 2018

The detention reservoir is a hydraulic structure that constructs a levee on the inland of river and sets up side weir in a section of the levee, and this facility stores a part of the flood volume in case of a flood event over a certain scale. In order to optimize the operation of detention reservoir, it is necessary to review the linkage with existing facilities in the river. In this study, the effect of water level reduction and the flow distribution was analyzed according to the location of the side weir in the detention reservoir considering the run-of-the-river gate. Two radial gates were installed in the experimental channel, and the water level in channel and the overflow of weir were measured by moving the location of the side weir upstream from the gate. As a results of experiment, it was confirmed that the water level reduction is more remarkable as the location of the side weir was closer to the gate, and the effect of flow distribution is not greatly changed. When two or more side weirs were operated, it is confirmed that the sufficient storage space was secured and the water level reduction effect with the location of the side weir is not large. In addition, the water level reduction rate according to the location of the side weir was estimated by empirical formula and it is provided as basic data that can be used in the planning of the detention reservoir.

• Journal of Wetlands Research
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• v.25 no.1
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• pp.14-25
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• 2023

Floodplain in a reservoir is defined as the area naturally formed between the design flood level and the normal pool level. Located around the dam reservoir, floodplain has been damaged in many different ways including cultivation. As it is impossible to restore all the damaged floodplain at once, it is necessary to determine their order of priority. This process considers various factors, among which the flooding frequency is an important hydrologic characteristic, Different from the floodplains in a river, all the floodplains around the given dam reservoir have the same flooding frequency. To overcome this problem, this study proposes to use the cumulative flooding area curve, which represents the cumulative flooding area corresponding to the reservoir water level. Especially, this study evaluates the flooding frequency of those water levels corresponding to the cumulative flooding area of 30%, 50% and 70%. As application examples, this study considers the five restoration candidates each selected in the Andong Dam, Imha Dam, Youngju Dam and Nam river Dam of the Nakdong River Basin. As a result, the cumulative flooding area curve was found to well represent the overall shape of the floodplain (i.e., steep-to-mild slope or mild-to-steep slope). Also, the flooding frequency of those water levels corresponding to the cumulative flooding area of 30%, 50% and 70% was found to be so effective to quantify the hydrologic characteristics of a floodplain.

• IE interfaces
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• v.21 no.1
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• pp.75-84
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• 2008

It is a difficult task for decision makers(DMs) to choose an appropriate release plan which balances the conflicts between water storage and hydro-electric energy generation in a multi-reservoir operation problem. In this study, we proposed a DEA-based ranking procedure by which the DM can rank the potential alternatives and select the best solution among the Pareto-optimal solutions. The proposed procedure can resolve the problem of mix inefficiency that may cause errors in measuring the efficiency of alternatives. We applied the proposed procedure to the multi-reservoir operation problem for the Geum-River basin and could choose the best efficient solution from the Pareto-set which were generated by the Coordinated Multi-Reservoir Operating Model.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.435-442
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• 2011

In this study, a regression model was developed for prediction of inflow temperature to support an effective thermal stratification simulation of Yongdam Reservoir, using the relationship between gaged inflow temperature and air temperature. The effect of reproductability for thermal stratification was evaluated using EFDC model by gaged vertical profile data of water temperature(from June to December in 2005) and ex-developed regression models. Therefore, in the development process, the coefficient of correlation and determination are 0.96 and 0.922, respectively. Moreover, the developed model showed good performance in reproducing the reservoir thermal stratification. Results of this research can be a role to provide a base for building of prediction model for water quality management in near future.

• Korean Journal of Hydrosciences
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• v.5
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• pp.57-70
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• 1994

For the system benefit optimization by considering risk or reliability from a multiple reservoir system using the Monte Carlo Technique, Many stochastically generated inflow series have to be used for the system analysis. In this study, the stochastically generated inflow series for the multiple reservoir system operation are preprocessed according to the considering system objectives and operating time periods. Through this procedure, several representative inflow series which have discrate probability levels and operation horizons are selected among the thousands of generated inflows. Then a deterministic optimization technique is applied to the hydropower energy estimation from the Han River Reservoir System which considers five reservoirs in this study. It took much less computational requirements than using the original Morite Carlo Technique, even though estimated result was almost similar.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.2
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• pp.13.2-20
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• 1995

An water balance model was formulated to simulate the change in water levels at the estuary reservoir from sluice gate releases and the inflow hydrographs, and an one-di- mensional flood routing model was formulated to simulate temporal and spatial varia- tions of flood hydrographs along the estuarine river. Flow rates through sluice gates were calibrated with data from the estuary dam, and the results were used for a water balance model, which did a good job in predicting the water level fluctuations. The flood routing model which used the results from two hydrologic models and the water balance model simulated hydrographs that were in close agreement with the observed data. The flood forecasting model was found to be applicable to real-time forecasting of water level fluc- tuations with reasonable accuracies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.22-27
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• 1999

This study was performed to investigated the contamination levels of harmful heavy metals were sampled from Aug. 1 to Aug. 31, 1997, at 9 areas in Cheonbuk area. The heavy metal contents were determinated by ICPS(Inductively Coupled Plasma Spectrometer) method. The levels of total lead, cadmium, aluminum, iron and copper were determined and the results were summarized as follows: The minimum and maximum values(ppm) of 9 areas of Carassius auratus were Pb: 2.03~6.19, Cd: 0.06~ 0.76, Al: 8.84~23.5, Zn: 10.68~48.71, Cu: 0.60~1.51ppm. Among the five heavy metals contents, the highest was zinc and the lowest was cadmium. The results showed that the contents of Pb, Cd, Al, Zn and Cu in Carassius auratus were lower than the FAO/WHO maximum allowance.