• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.372-376
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• 2010

기후변화에 의한 각 분야의 영향예측과 평가가 전 세계적으로 진행되고 있으며, 이 결과가 국제기관들에 의해 종합 정리되어 발표되고 있다. 또한 이를 토대로 범 지구차원, 국가차원의 대응방안에 관한 연구가 지속적으로 이루어지고 있다. 우리나라는 아시아 몬순 기후 지역으로 년 평균 강수량이 1,270mm 정도로 세계 평균의 1.3배 정도로 비교적 많은 편이나 1인당 강수 총량은 세계평균의 1/11로서 물부족 국가에 속하고 있다. 년간 강수량의 분포는 계절적, 지역적으로 큰 차이를 보여 다우기인 6월에서 9월까지의 강수량이 2/3을 차지하며 그 후 이듬해 3월 까지의 강수량이 전체의 1/5에 불과해 여름에는 집중호우로 인한 홍수가 빈발하며, 겨울과 봄에는 물 부족이 발생하게 된다. 또한 기후변화로 인한 강수량과 기온은 지역적으로 차이는 있으나 계속적으로 증가하는 것으로 분석됨에 따라 기후변화에 따른 농업수자원은 더욱 취약해 질 것으로 판단된다. 따라서 본 연구에서는 우리나라 농업용저수지에 대한 필요저수량을 예측하였다. 그 결과 2020s, 2050s, 2080s 및 각 지역별로 많은 차이가 났다. MM5의 경우 13.1%~37.4%, CF방법에서는 -7.3%~36.2%, LARS-WG방법에서는 -33.1%~37.8%로 지역별 및 년도별로 남거나 부족한 것으로 나타났다. 이는 미래에 내리는 강우가 관개기에 얼마나 큰 영향을 미치느냐에 따라 크게 달라지는 것으로 분석되었다.

• Journal of Korean Society of Rural Planning
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• v.27 no.1
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• pp.1-8
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• 2021

The study aims to draw out implications regarding systematic reservoir management through analyzing the reservoir conservation activities and policies in Hyogo Prefecture which has the most agricultural reservoirs in Japan and similar agricultural form to that of Korea. The results are as follows. First, it turns out that consistency in policies and persistent drive are key to success. Since the late 1990s, the Hyogo Prefectural government has expanded the reservoir conservation policies, consistently trying to ellicit the multifunctionality of reservoir, and also has shown persistent drive toward the conservation policies through systematic process. Second, it is clear that the Prefectural government has shown a great degree of activeness. It established ordinances before acts were legislated by the central government. In addition, the Hyogo Prefectural government ran a supportive organization with its own funds. Third, the establishment of systematic enforcement system played a critical role. The efficiency in the policy enforcement derived from the dual conferences, Prefectural-level conference dealing with the related policies throughout the Prefecture, and local-level conference discussing policies based on regional characteristics.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.110-118
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• 2022

Frequent drought damage has resulted in the polarization of water resources. In Korea, local periodic abnormal droughts continued to occur between 2011 and 2017, resulting in decreased water storage rates of small-scale reservoirs designed with a frequency of 10-year droughts. This decrease can degrade water quality and limit the use of already secured quantities. Therefore, to prepare for and overcome drought, quality management and recalculation of drought frequency are required. This study estimates the potential pollutants causing quality changes in the reservoir. In addition, it reviews the decrease in storage and consequent changes in the quality of a reservoir during drought.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.34-34
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• 2023

The Chah-Nimeh reservoirs, which are a sort of natural lakes located in the border of Iran and Afghanistan, are the main drinking and agricultural water resources of Sistan arid region. Considering the occurrence of intense seasonal wind, locally known as levar wind, this study aims to explore the possibility to provide a TSM (Total Suspended Matter) monitoring model of Chah-Nimeh reservoirs using multi-temporal satellite images and in-situ wind speed data. The results show that a strong correlation between TSM concentration and wind speed are present. The developed empirical model indicated high performance in retrieving spatiotemporal distribution of the TSM concentration with R²=0.98 and RMSE=0.92g/m³. Following this observation, we also consider a machine learning-based model to predicts the average TSM using only wind speed. We connect our in-situ wind speed data to the TSM data generated from the inversion of multi-temporal satellite imagery to train a neural network based mode l(Wind2TSM-Net). Examining Wind2TSM-Net model indicates this model can retrieve the TSM accurately utilizing only wind speed (R²=0.88 and RMSE=1.97g/m³). Moreover, this results of this study show tha the TSM concentration can be estimated using only in situ wind speed data independent of the satellite images. Specifically, such model can supply a temporally persistent means of monitoring TSM that is not limited by the temporal resolution of imagery or the cloud cover problem in the optical remote sensing.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.121-133
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• 2015

The TANK model has been widely used in rainfall-runoff modeling due to its simplicity of concept and computation while achieving forecast accuracy. A major barrier to the model application is to determine parameter values for ungauged watersheds, leading to the need of a method for the parameter estimation. The objective of this study was to develop regression equations for estimating the 3th TANK model parameters considering their variations for the ungauged watersheds. Thirty watersheds of dam sites and stream stations were selected for this study. A genetic algorithm was used to optimize TANK model parameters. Watershed characteristics used in this study include land use percent, watershed area, watershed length, and watershed average slope. Generalized equations were derived by correlating to the optimized parameters and the watershed characteristics. The results showed that the TANK model, with the parameters determined by the developed regression equations, performed reasonably with 0.60 to 0.85 of Nash-Sutcliffe efficiency for daily runoff. The developed regression equations for the TANK model can be applied for the runoff simulation particularly for the ungauged watersheds, which is common for upstream of agricultural reservoirs in Korea.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1308-1318
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• 2014

The specific freshwater environment of reservoirs formed by streams has not been well studied. In this paper, the bacterioplankton community in such a reservoir, the Huangqian Reservoir in eastern China, was described using culture-independent molecular methods. We found that the most dominant bacterioplankton were affiliated with Cyanobacteria, followed by Betaproteobacteria, Bacteroidetes, Gammaproteobacteria, and Actinobacteria. Both bacterial abundance and diversity increased along the direction of water flow, and the 16S rRNA gene copy number in the water outlet was nearly an order of magnitude higher than that in the water inlet. Pearson correlation analyses indicated that nitrate had a significantly negative correlation with the bacterial abundance (p < 0.05) and that ammonium was positively correlated with bacterial abundance (p < 0.05). Interestingly, owing to a remarkably negative correlation (p < 0.01), the ratio of nitrate and ammonium might serve as a good pre dictor of the relative abundance of bacterioplankton. According to redundancy analysis, nitrate and dissolved oxygen were the major factors influencing the bacterial communities. In addition, we attempted to determine the reasons why such a reservoir could maintain good ecological balance for a period of decades, and we found that the environmental factors and bacterial communities both played critical roles. This research will benefit our understanding of bacterial communities and their surrounding environments in freshwater ecosystems.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.107-120
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• 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.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.1057-1069
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• 2020

For most upland crops in Korea, underground water is used to ensure an adequate water supply. Thus, surface water storage tanks are needed to supply surface water from reservoirs or streams. This study discusses the design, manufacture and monitoring of a water storage tank capable of reliably supplying water to crops and preventing the inflow of floating debris. The study was conducted in an apple orchard in Yesan-gun, Chungcheongnam-do in Korea. Based on the water requirements of the crops and size of the orchard, a required flow volume of about 0.6 ㎥·h-1 was determined, along with a surface water storage tank capacity of 1.2 ㎥. Following a comparison with other materials, stainless steel (STS) was used to construct the water tank. The tank was designed to provide 14 hours of irrigation, enabling a small-capacity, cost-efficient tank design to be used. A surface water irrigation test was performed using the surface water storage tank. The average surface water irrigation flow rate was 0.00045 ㎥·m-2·h-1. The water quality test showed that the pH, suspended solids (SS), total nitrogen (TN), and total phosphorus (TP) values satisfied the reference values for agricultural water. The test results showed that the surface water storage tank evaluated in this study allows for crop irrigation when there is a lack of groundwater during droughts.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.5
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• pp.25-35
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• 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.

• Journal of Ecology and Environment
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• v.31 no.2
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• pp.147-151
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• 2008

Feeding methods of five species of herons and egrets were studied in an agricultural landscape in Asan city, Chungcheongnam-do, Korea in 2006. Grey herons primarily hunted while standing, whereas great egrets fed while walking slowly. Two smaller species, little and cattle egrets, were active foragers, feeding both while walking quickly and walking slowly. Little egrets were the only species using the foot stirring method. The medium-sized heron, intermediate egrets, foraged mainly while walking slowly or leaning. For grey herons, great egrets and little egrets, the frequency of use of different feeding methods was different between habitats: these species used the leaning method more frequently in rice fields than in reservoirs and ditches. Also, most herons (all species other than great egrets) showed seasonal changes in their feeding methods that are related to changes in habitat condition.