• 한국농공학회논문집
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• 제54권2호
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• pp.77-86
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• 2012

This study was aim to predict future land-cover changes and to analyze regional land-cover changes in irrigation areas and agricultural reservoir watersheds under climate change scenario. To simulate the future land-cover under climate change scenario - A1B of the SRES (Special Report on Emissions Scenarios), Dyna-CLUE (Conversion of Land Use Change and its Effects) was applied for modeling of competition among land-use types in relation to socioeconomic and biophysical driving factors. For the study areas, 8 agricultural reservoirs were selected from 8 different provinces covering all around nation. The simulation results from 2010 to 2100 suggested future land-cover changes under the scenario conditions. For Madun reservoir in Gyeonggi-do, total decrease amount of paddy area was a similar amount of 'Base demand scenario' of Water Vision 2020 published by MLTMA (Ministry of Land, Transport and Maritime Affairs), while the decrease amounts of paddy areas in other sites were less than the amount of 'High demand scenario' of Water Vision 2020. Under A1B scenario, all the land-cover results showed only slight changes in irrigation areas of agricultural reservoirs and most of agricultural reservoir watersheds will be increased continuously for forest areas. This approach could be useful for evaluating and simulating agricultural water demand in relation to land-use changes.

• 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 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.486-492
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• 1999

One of the purpose of the reservoir operation is minimizing theinnudation area in the downstream reaches during flood period.l To execute the gate operation properly , it requires lots of real-time data such as rainfall, reservoir level, and water level in the downstrea. Gate operation model was developed with the flood discharge obtained from real-time flood forecasting model and the criterion prepared from the past history of gate operation. Water level in the downstream would be increased by the releasing discharge from the spillway and the area of paddy land flooded in a certain detph and time would be estimated usnig GIS map. Gate operation model was applied to the Yedang reservoir, and the flooded area, depth and time in the paddy land was estimaged.

• 한국환경과학회지
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• 제28권11호
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• pp.1027-1032
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• 2019

This study aimed to analyze the prioritized area for the functional change of agricultural reservoir according to the rapid urbanization and social changes through the mapping method. Changwon-si, Gimhae-si, and Jinju-si in Gyeongnam province were selected as the study area, considering the results of land-use and cluster analysis. As the planning unit of management area, watershed was used and land coverage map from 1975 to 2015 were analyzed for changes of land use. The reduction ratio (%) of farmland was calculated for identifying the changes in 2013 compared to 1975. As a result, the reduction ratio was 11.9% for Changwon-si, 12.2% for Gimhae-si and 9.3% for Jinju-si, and the number of watershed having functionally reduced potential-area was relatively high in the proportion to the city size.

• 한국농공학회논문집
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• 제63권6호
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• pp.27-37
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• 2021

Conversion of rice paddy field to upland has been accelerated as the central government incentivizes more profitable upland crop cultivation. The objective of this study was to investigate the current status and conversion trend from paddy to upland for the reservoir irrigation districts. Total 605 of reservoir irrigation districts whose beneficiary area is greater than 200 ha were selected for paddy-to-upland conversion analysis using the land cover maps provided by the EGIS of the Ministry of Environment. The land cover data of 2019 was used to analyze up-to-date upland conversion status and its correlation with city proximity, while land cover change between 2007 and 2019 was used for paddy-to-upland conversion trend analysis. Overall 14.8% of the entire study reservoir irrigation area was converted to upland cultivation including greenhouse and orchard areas. Approximately the portion of paddy area was reduced by 17.8% on average, while upland area was increased by 4.9% over the 12 years from 2007 to 2019. This conversion from paddy to upland cultivation was more pronounced in the Gyoenggi and Gyeongsang regions compared to other the Jeolla and Chungcheong provinces. The increase of upland area was also more notable in proximity of the major city. This study findings may assist to identify some hot reservoir districts of the rapid conversion to upland cultivation and thus plan to transition toward upland irrigation system.

• 한국환경생태학회지
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• 제22권6호
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• pp.632-639
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• 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.

• 한국농공학회논문집
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• 제63권1호
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• pp.89-102
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• 2021

Soils in agricultural lands contain large amount of organic matter and nutrients due to the injected fertilizers and manure. During heavy rain, surface water and base runoff pollutants flows into a nearby stream or lake with eroded soil from agricultural lands. On the other hands, agricultural lands near the lake are inundated due to the increase of the water level in the lake, leading to organic matter and nutrient release from the inundated soil. In this study, releasing rates of nutrient salts and organic substances were analyzed for the soil in the agricultural land, where cultivation activities has been carried out and periodically flooded, to account for the possibility of contamination from the inundated agricultural land in reservoir areas The experiment results have shown that COD was released from the soil in anaerobic conditions, and T-P was released in both anaerobic and aerobic conditions. However, in the case of T-N, it was found that the runoff by soil was not made before the rainfall occurred, and when the soil was impound due to rainfall, the elution occurred under the aerobic conditions. Through the results of this study, it was possible to account for the effect of flooded agricultural lands on the water quality in the lake, and this could be reflected in an efficient agricultural non-point pollution management policy. In order to determine the precise releasing rate for each agricultural land, it is believed that the leaching experiment for paddy fields and grasslands are needed.

• 한국농공학회논문집
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• 제62권3호
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• pp.63-69
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• 2020

Recently, the Yedang reservoir needs reflecting the demands of the public and administration, including change of reservoir status and paradigm shift of users, as well as planning programs to activate the area as a special health zone for tourism, leisure, recreation and experience at the local government level. Previous Optimum Equipment model (OEM) preferentially considers the creation of waterfront. This study shows the operation model for readjustment of water supply facilities according to the limit of the level of the beneficiaries. Results show the renovation cycle of Yedang tourist resort and the suspension bridge through developed model simulation. In addition to securing quantity for the supply of agricultural water and the function of water protection, the multi-function of the agricultural reservoir shall be re-evaluated to enhance the diverse availability of the agricultural reservoir. The county office should also boost various availability at various levels to revitalize the local economy, such as producing pleasant and safe places and offering safe food for people.

• 한국농공학회논문집
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• 제58권5호
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• pp.19-28
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• 2016

This study was to design the optimal locations of the water level monitoring to quantify the agricultural water use in irrigation area supplied from an agricultural reservoir. In most of agricultural areas without TM/TC (Tele-Monitoring and Tele-Control) or monitoring network, irrigation water have been supplied on conventional experience and agricultural reservoir have been operated based on the operating simulation results by HOMWRS (Hydrological Operation Model for Water Resources System). Therefore, this study quantified the amount of agricultural water use in an irrigation area (Musu Reservoir, Jincheon-gun) by establishing water level monitoring network and analyzed the agricultural water saving effect. According to the evaluation of the economic values for water saving effect, the saving agricultural water of 1.7 million ton was analyzed to have economic values of 0.85 million won as water for living, and 1.78 million won as water for industrial use. It is identified to secure economic feasibility of the new water monitoring network by establishing one monitoring point in the entrance, irrigation area and endpoint through the economic analysis.

• 한국농공학회논문집
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• 제66권1호
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• pp.49-66
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• 2024

Extreme rainfall will become intense due to climate change, increasing inundation risk to agricultural land. Hydrological and hydraulic simulations for the entire watershed were conducted to analyze the impact of climate change. Rainfall data was collected based on past weather observation and SSP (Shared Socio-economic Pathway)5-8.5 climate change scenarios. Simulation for flood volume, reservoir operation, river level, and inundation of agricultural land was conducted through K-HAS (KRC Hydraulics & Hydrology Analysis System) and HEC-RAS (Hydrologic Engineering Center - River Analysis System). Various scenarios were selected, encompassing different periods of rainfall data, including the observed period (1973-2022), near-term future (2021-2050), mid-term future (2051-2080), and long-term future (2081-2100), in addition to probabilistic precipitation events with return periods of 20 years and 100 years. The inundation area of the Aho-Buin district was visualized through GIS (Geographic Information System) based on the results of the flooding analysis. The probabilistic precipitation of climate change scenarios was calculated higher than that of past observations, which affected the increase in reservoir inflow, river level, inundation time, and inundation area. The inundation area and inundation time were higher in the 100-year frequency. Inundation risk was high in the order of long-term future, near-term future, mid-term future, and observed period. It was also shown that the Aho and Buin districts were vulnerable to inundation. These results are expected to be used as fundamental data for assessing the risk of flooding for agricultural land and downstream watersheds under climate change, guiding drainage improvement projects, and making flood risk maps.