• 한국환경생태학회지
• /
• 제22권6호
• /
• pp.632-639
• /
• 2008

기러기류의 분포양상과 시기에 따른 분포변화에 대한 연구를 2006년 10월부터 2007년 3월까지 천수만 부남호와 간월호에서 실시하였다. 기러기류는 주간에 주로 농경지에 분포하였으며, 해안에서는 관찰되지 않았다. 격자별 최대개체수를 이용한 분포도에서, 농경지에서 관찰된 기러기류는 부남호와 간월호 지역 모두 면적이 넓은 지역에 대한 분포비율이 높았다. 특히, 잠자리지역인 저수지와 가까운 지역의 취식비율이 높았다. 기러기류의 주간 취식지는 부남호와 간월호 모두 초기 10월에는 잠자리 지역인 저수지 인근 농경지를 이용하였지만, 월동 중기 1월 이후에는 잠자리에서 먼 지역을 취식지로 이용하였다. 월동말기인 3월에는 개체수 규모가 크게 줄어들고 잠자리에서 먼 지역의 농경지를 더 높은 비율로 이용하였다. 저수지에서 가까운 1km 이내 지역의 평균 개체수가 다른 지역에 비하여 높았다. 월동초기($10{\sim}11$월)에는 저수지 인근지역이 취식지로 선호되었지만, $12{\sim}1$월 그리고, $2{\sim}3$월로 갈수록 평균 서식개체수의 차이가 감소하여 유의한 차이가 없었다. 1km 이내의 격자지역은 초기에 매우 높은 서식지 이용률을 보이지만 차차 감소하여 2월 이후 다시 증가하였다. 반면, 저수지로부터 2km 이상 떨어진 지역은 초기에 매우 낮은 서식지 이용률을 보이지만, 점차 증가하여 1월말에 최대 이용률을 보이고, 이후 점차 감소하였다. 1km 이상2km 미만에 해당하는 지역은 초기에 2km 이상지역보다 이용률이 높고, 1km 미만의 지역보다 낮은 서식지 이용률을 보이지만 11월까지 증가하다가 점차 감소하는 양상을 보였다. 본 연구결과는 기러기류의 취식지 선택이 잠자리와의 거리에 영향을 받으며, 취식무리의 체류 시간에 따라서 먹이량이 감소하여 취식지 선택 양상이 변화하는 것을 보여준다.

• 한국습지학회지
• /
• 제21권spc호
• /
• pp.80-89
• /
• 2019

본 논문의 목적은 금강유역을 대상으로 Standardized Precipitation Index (SPI) 기상학적 가뭄지수, 농업용 저수지 가뭄지수(Reservoir Drought Index, RDI)간의 관계를 통해 기상학적 가뭄이 농업에 미치는 상관성을 분석하는데 있다. 2014년부터 2016년까지의 강수량, 농업용 저수율 자료를 수집하여 가뭄지수를 산정하였으며, 기상학적 가뭄과 농업가뭄간의 상관성을 평가하기 위해 Pearson 상관계수와 Receiver Operation Characteristic (ROC) 분석을 실시하였다. 상관분석결과 SPI-6와 RDI의 Pearson 및 ROC 적중룰이 각각 0.606, 0.722으로 가장 높게 분석되었고 가뭄의 공간적 발생패턴을 분석하기 위해 공간분포된 SPI-6와 RDI를 중첩한 결과 2015년 8월부터 2015년 10월의 심한 가뭄 발생 시 미호천 상류 유역과 논산천 유역에서 중복적으로 가뭄의 심도의 차이가 발생하는 것을 확인하였다. 저수지 가뭄이 발생한 지역에 대한 저수지의 제원을 이용하여 분석을 수행한 결과, RDI 가뭄이 크게 나타난 지역은 유역배율이 작은 저수지들이 많이 모여 있는 지역일수록 극심한 가뭄을 겪는 것으로 분석되어, 유역배율에 따라 저수지의 농업가뭄 대응능력에 차이가 있음을 확인하였다.

• 한국농공학회논문집
• /
• 제61권1호
• /
• pp.107-120
• /
• 2019

Reservoir water level data identify the current water storage of the reservoir, and they are utilized as primary data for management and research of agricultural water. For the reservoir storage management, Korea Rural Community Corporation (KRC) installed water level stations at around 1,600 agricultural reservoirs and has been collecting the water level data every 10 minutes. However, various kinds of outliers due to noise and erroneous problems are frequently appearing because of environmental and physical causes. Therefore, it is necessary to detect outlier and improve the quality of reservoir water level data to utilize the water level data in purpose. This study was conducted to detect and classify outlier and normal data using two different models including the threshold model and the artificial neural network (ANN) model. The results were compared to evaluate the performance of the models. The threshold model identifies the outlier by setting the upper/lower bound of water level data and variation data and by setting bandwidth of water level data as a threshold of regarding erroneous water level. The ANN model was trained with prepared training dataset as normal data (T) and outlier (F), and the ANN model operated for identifying the outlier. The models are evaluated with reference data which were collected reservoir water level data in daily by KRC. The outlier detection performance of the threshold model was better than the ANN model, but ANN model showed better detection performance for not classifying normal data as outlier.

• 한국농공학회논문집
• /
• 제64권6호
• /
• pp.1-12
• /
• 2022

Estuary reservoirs were artificial reservoir with seawalls built at the exit points of rivers. Although many water resources can be saved, it is difficult to manage due to the large influx of pollutants. To manage this, it is necessary to analyze watersheds and reservoirs through accurate modeling. Therefore, in this study, we linked the Hydrological Simulation Program-FORTRAN (HSPF), Environmental Fluid Dynamics Code (EFDC), and Water quality Analysis Simulation Program (WASP) models to simulate the hydrology and water quality of the watershed and the water level and quality of estuary lakes. As a result of applying the linked model in stream, R² 0.7 or more was satisfied for the watershed runoff except for one point. In addition, the water quality satisfies all within 15% of PBIAS. In reservoir, R² 0.72 was satisfied for water level and the water quality was within 15% of T-N and T-P. Through the modeling system, We applied upstream pollutant management scenarios to analyze changes in water quality in estuary reservoirs. Three pollution source management were applied as scenarios, the improvement of effluent water quality from the sewage treatment plant and the livestock waste treatment plant was effective in improving the quality of the reservoir water, while the artificial wetland had little effect. Water quality improvement was confirmed as a measure against upstream pollutants, but it was insufficient to achieve agricultural water quality, so additional reservoir management is required.

• 한국농공학회논문집
• /
• 제65권5호
• /
• pp.25-35
• /
• 2023

The estuary reservoir is a major source of agricultural water in Korea; for effective and sustainable water resource management of the estuary reservoir, it is crucial to comprehensively consider various water resource factors, including water supply, flood, and pollutant management, and analyze future runoff changes in consideration of environmental changes such as climate change. The objective of this study is to estimate the impact of future climate change on the runoff characteristics of an estuary reservoir watershed. Climate data on future Shared Socioeconomic Pathway (SSP) scenarios were derived from two Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 6 (CMIP6). The Hydrological Simulation Program-Fortran (HSPF) was used to simulate past and future long-term runoff of the Ganwol estuary reservoir watershed. The findings showed that as the impact of climate change intensified, the average annual runoff in the future period was higher in the order of SSP5, SSP3, SSP1, and SSP2, and the ratio of runoff in July decreased while the ratio of runoff in October increased. Moreover, in terms of river flow regime, the SSP2 scenario was found to be the most advantageous and the SSP3 scenario was the most disadvantageous. The findings of this study can be used as basic data for developing sustainable water resource management plans and can be applied to estuary reservoir models to predict future environmental changes in estuary reservoirs.

• 한국농공학회논문집
• /
• 제54권3호
• /
• pp.11-17
• /
• 2012

In this study, an experiment with large-scale model was performed according to raising embankment in order to investigate the cause of collapse by a change in water level of reservoir. Also, the settlement and pore water pressure by high water level and a rapid drawdown were compared and analyzed. After raising embankment for inclined core, there was no infiltration by leakage. For the vertical core, the pore water pressure showed a largely change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but vertical core showed a largely change in pore water pressure. A settlement after a raising embankment showed a larger measure of settlement than before the raising embankment. The leakage quantity before a raising embankment and an inclined extension showed no leakage. Leakage in vertical extension was measured 160 $l$. From the result, a instrument system that can accurately estimate a change of pore water pressure shall be established for a rational maintenance and stabilization of raising embankment for agricultural reservoir.

• 농업과학연구
• /
• 제49권4호
• /
• pp.759-769
• /
• 2022

As the variability of recent rainfall is increasing, it is becoming important to recognize the possibility of changes in the current reservoir state in advance and to inspect the stability based on accurate evaluation standards. However, the evaluation standards for the state change factors of reservoirs are still not suitable for agricultural reservoirs and thus much improvement is needed. Therefore, in this study, the evaluation criteria for state change factors specialized for small reservoirs were categorized and standards were prepared by considering factors that may cause state changes on the dam crest, upstream slope, and downstream slope of the embankment. The categorized results were configured based on the number of mentions of the precision safety inspection report on major defects in 102 reservoirs and the defect factors found in field investigations. The findings of the study indicated that the current state change standards require many revisions for excessive or unnecessary state change factors in the reservoir. Specifically, the deletion of measurement gauges not applicable to the reservoir, the addition of defects found in the reservoir, and the scope of use of the term were proposed. The results of this study can contribute to efficient system operation and management by improving the deficiencies in the system and introducing a new state change factor.

• 한국농공학회지
• /
• 제29권3호
• /
• pp.125-137
• /
• 1987

The purpose of this paper is to examine some difficulties in water management of agricultural reservoirs in Korea, for there are approximately more than 15,000 reservoirs which are now being utilized for the purpose of irrigation, along with the much amount of expenses and labors to be invested against droughts and floods periodically occurred. Recently, the effective use of water resources in the agricultural reservoirs with a single purpose, is becomming multiple according to the alterable environment of water use. Therefore, the task to allocate agricultural water rationally and economically must be solved for the multiple use of agricultural reservoirs. On the basis of the above statement, this study aims at suggesting the rational method of water management by introducing an optimal technique to allocate the water in an existing agricultural reservoir rationally, for the sake of maximizing the economic effect. To achieve this objective, a reservoir, called "0-Bongje" as a sample of the case study, is selected for an agricultural water development proiect of medium scale. As a model for the optimum allocation of water in the multi-purpose use of reservoirs a linear programming model is developed and analyzed. As a result, findings of the study are as follows : First, a linear programing model is developed for the optimum allocation of water in the multi-purpose use of agricultural reservoirs. By adopting the model in the case of reservoir called "O-Bongje," the optimum solution for such various objects as irrigation area, the amount of domestic water supply, the size of power generation, and the size of reservoir storage, etc., can be obtained. Second, by comparing the net benefits in each object under the changing condition of inflow into the reservoir, the factors which can most affect the yearly total net benefit can be drawn, and they are in the order of the amount of domestic water supply, irrigation area, and power generation. Third, the sensitivity analysis for the decision variable of irrigation which may have a first priority among the objects indicate that the effective method of water management can be rapidly suggested in accordance with a condition under the decreasing area of irrigation. Fourth, in the case of decision making on the water allocation policy in an existing multi-purpose reservoir, the rapid comparison of numerous alternatives can be possible by adopting the linear programming model. Besides, as the resources can be analyed in connection with various activities, it can be concluded that the linear programing model developed in this study is more quantitative than the traditional methods of analysis. Fifth, all the possible constraint equations, in using a linear programming model for adopting a water allocation problem in the agricultural reservoirs, are presented, and the method of analysis is also suggested in this study. Finally, as the linear programming model in this study is found comprehensive, the model can be adopted in any different kind of conditions of agricultural reservoirs for the purpose of analyzing optimum water allocation, if the economic and technical coefficients are known, and the decision variable is changed in accordance with the changing condition of irrigation area.

• 한국농공학회논문집
• /
• 제60권1호
• /
• pp.121-131
• /
• 2018

Past climate change influences multiple environmental aspects, certain of which are specifically related to agricultural water resources such as water supply and demand. Changes on rainfall and hydrologic patterns can increases the occurrence of reservoir water shortage and affect the future availability of agricultural water resources. It is a main concern for sustainable development in agricultural water resources management to evaluate adaptation capability of water supply under the changing climate and farming methods in paddy field. The purpose of this study is an evaluation method of design frequency of drought and water supply safety for agricultural reservoirs to investigate evidence of climate change occurrences at a local scale. Thus, it is a recommended practice in the development of water supply management strategies on reservoir operation under changing climate and farming methods in paddy field.

• 한국농공학회지
• /
• 제43권6호
• /
• pp.174-186
• /
• 2001

Excessive outflow of pollutant loads resulting from rapid industrialization has unbalanced the water ecosystem, deteriorating the water quality environment severely. Therefore, measures for improving the water quality are necessary to maintain clean reservoir water and restore water-friendly spaces. A water quality model which is capable of simulating daily reservoir water quality was developed. The model had been applied to Masan reservoir and Wanggung reservoir in Korea. The model appeared to be satisfactory in representing the trend of water quality variations by comparing measured and simulated results. The model had been also applied to assess water purification techniques such as dredged pool, floating island and vegetation purification system. The model was considered to assess the effect of water purification techniques on reservoir water quality improvement. The results of water quality simulation for lake water purification techniques showed that a large facility would be needed to meet the targeted water quality of the reservoir when only one technique is applied. To effectively improve the quality of the polluted reservoir water, it is therefore recommended that pollutant sources should first be controlled, and a combination of the water purification techniques applied to make the utmost use of their secondary effects such as conservation of the reservoir volume capacity, establishment of a recreation space, promotion of bio-diversity, and improvement of the lake landscape.