• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.77-85
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• 2013

The efficient operation and management strategies of reservoirs in irrigation periods of drought events are an essential element for drought planning and countermeasure. Korea Rural Community Corporation has developed the real-time water level observation system of agricultural reservoirs to efficiently operate reservoirs, however, it is not possible to predict drought conditions, and only provides information of current situation. Hence, it is necessary to evaluate accurate irrigation vulnerability and efficiently reservoir operation rules using current water level. In this paper, the improvement methods of reservoir operation planning were developed with water supply vulnerability characteristic curves comparing to automatic water gauge at agricultural reservoirs. The 11 reservoirs were simulated applying the reservoir operation rules which was determined by irrigation vulnerability characteristic curves criteria and real time water level, and evaluated water supply situation in 2012 year. The analysis of results can be identified probabilistic possibility of water supply failures compared with the existing reservoir operation criteria. These results of efficient reservoir operation rules can be achieved enable irrigation planners to optimally manage available water resources for decision making, and contributed to maintain the water supply according to demand strategy for agricultural reservoirs management.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.59-67
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• 2015

Because reservoirs that supply irrigation water play an important role in water resource management, it is necessary to evaluate the vulnerability of this particular water supply resource. The purpose of this study is to provide water supply risk maps of agricultural reservoirs in South Korea using irrigation vulnerability model and cluster analysis. To quantify water supply risk, irrigation vulnerability indices are estimated to evaluate the performance of the water supply on the agricultural reservoir system using a probability theory and reliability analysis. First, the irrigation vulnerability probabilities of 1,346 reservoirs managed by Korea Rural Community Corporation (KRC) were analyzed using meteorological data on 54 meteorological stations over the past 30 years (1981-2010). Second, using the K-mean method of non-hierarchical cluster analysis and pre-simulation approach, cluster analysis was applied to classify into three groups for characterizing irrigation vulnerability in reservoirs. The morphology index, watershed area, irrigated area, and ratio between watershed and irrigated area are selected as the clustering analysis parameters. It is suggested that the water supply risk map be utilized as a basis for the establishment of risk management measures, and could provide effective information for a reasonable decision making on drought risk mitigation.

• Journal of Korea Water Resources Association
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• v.46 no.2
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• pp.183-193
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• 2013

Selecting the evaluation index to determine water resources system design yield is an important problem for water resources engineers. Reliability, resilience and vulnerability are three widely used indices for yield analysis. However, there is an overlap region between indices as well as resilience and vulnerability can show improvement in non-monotonic phenomena although yield condition becomes worse. These problems are usually not recognized and the decisions are made according to calculated estimates in real situation. The reason for this is caused by a diverse characteristics of water resources system such as seasonal variability of hydrologic characteristics and water demands. In this study, the applicability of resilience and vulnerability for multi indices application in addition to reliability which is applied generally is examined. Based on highly seasonal irrigation water demand ratio, the correlation and non-monotonic phenomena of each index are analyzed for seven selected reservoirs. Yongdam reservoir which supplies constant water supply showed the general tendency, but Chungju, Andong, Namgang and other reservoirs which supplies irrigation water showed clear non-monotonic phenomena in resilience and vulnerability.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.31-40
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• 2019

In order to implement practical alternatives to proactively cope with the agricultural drought, the potential vulnerability of irrigation pumping stations to agricultural drought was quantitatively evaluated. Data for the 124 pumping stations which are correlatable to the three proxy variables, i.e. exposure, sensitivity, and adaptive capacity was collected by the Korea Rural Community Corporation, and then standardized considering distribution of each data set. Finally, the vulnerability index was calculated by multiplying the weights determined by the expert survey. The results showed that the vulnerability index ranged from 0.709 to 0.331 and the most vulnerable pumping stations such as Judam, Wongoo and Jinahn were mostly located in Gyeongbuk province likely because of the climatological characteristics with high temperature and low rainfall around this area. In addition, it was found that the adaptive capacity was a dominant factor comparing to exposure or sensitivity proxy variables in contributing to the vulnerability. It is therefore recommended that more practical alternatives should be employed to effectively reduce the vulnerability of an individual pumping station to agricultural drought. Furthermore, the corresponding data related to adaptive capacity should be systematically organized and managed at a field level to design reliable adaptation strategies.

• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.6
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• pp.141-150
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• 2021

In order to assess the impact of climate change on irrigation reservoirs, climate exposure (EI), sensitivity (SI), and potential impact (PI) were evaluated for 1,651 reservoirs nationwide. Climate exposure and sensitivity by each reservoir were calculated using data collected from 2011 to 2020 for seven proxy variables (e.g. annual rainfall) and six proxy variables (e.g. irrigation days), respectively. The potential impact was calculated as the weighted sum of climate exposure and sensitivity, and was classified into four levels: 'Low (PI<0.4)', 'Medium (PI<0.6)', 'High (PI<0.8)', and 'Critical (PI≥0.8)'. The result showed that both the climate exposure index and the sensitivity index were on average high in Daegu and Gyeongbuk with high temperature and low rainfall. About 79.8% of irrigation reservoirs in Daegu, Gyeongbuk, and Ulsan with high climate exposure and sensitivity resulted in a 'High' level of potential impact. On the contrary, 64.5% of the study reservoirs in Gyeongnam and Gangwon showed 'Low' in potential impact. In further studies, it is required to reorganize the proxy variables and the weights in accordance with practical alternatives for improving adaptive capacity to drought, and it is expected to contribute to establishing a framework for vulnerability assessment of an irrigation reservoir.

• Journal of Korean Society of Rural Planning
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• v.12 no.1 s.30
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• pp.37-48
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• 2006

The objectives of this study were to develop an evaluation method of regional vulnerability to agricultural drought and to classify the vulnerability patterns. In order to test the method, 24 city or county areas of Gyeonggi-do were chose. First, statistic data and digital maps referred for agricultural drought were defined, and the input data of 31 items were set up from 5 categories: land use factor, water resource factor, climate factor, topographic and soil factor, and agricultural production foundation factor. Second, for simplification of the factors, principal component analysis was carried out, and eventually 4 principal components which explain about 80.8% of total variance were extracted. Each of the principal components was explained into the vulnerability components of scale factor, geographical factor, weather factor and agricultural production foundation factor. Next, DVIP (Drought Vulnerability Index for Paddy), was calculated using factor scores from principal components. Last, by means of statistical cluster analysis on the DVIP, the study area was classified as 5 patterns from A to E. The cluster A corresponds to the area where the agricultural industry is insignificant and the agricultural foundation is little equipped, and the cluster B includes typical agricultural areas where the cultivation areas are large but irrigation facilities are still insufficient. As for the cluster C, the corresponding areas are vulnerable to the climate change, and the D cluster applies to the area with extensive forests and high elevation farmlands. The last cluster I indicates the areas where the farmlands are small but most of them are irrigated as much.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.177-177
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• 2023

The impacts of dams on transboundary flow are complex and challenging to project and manage, given the potential moderating influence of a broad range of anthropogenic and natural factors. This study presents a global meta-analysis of 168 studies that examines the effect magnitude of dams on downstream seasonal, annual flow, and hydrological extremes risk on 39 hotspot transboundary river basins. The study also evaluates the impact of 13 factors, such as climate, basin characteristics, dams' design and types, level of transboundary cooperation, and socioeconomic indicators, on the heterogeneity of outcomes. The findings reveal that moderators significantly influence the impact of dams on downstream flow, leading to considerable heterogeneity in outcomes. Transboundary cooperation emerges as the key factor that determines the severity of dams' effect on both dry and wet season's flows at a significance level of 0.01 to 0.05, respectively. Specifically, the presence of water-supply and irrigation dams has a significant (0.01) moderating effect on dry-season flow across basins with high transboundary cooperation. In contrast, for wet-season flow, the basin's vulnerability to climate extremes is associated with a large negative effect size. The various moderators have varying degrees of influence on the heterogeneity of outcomes, with the aridity index, population density, GDP, and risk level of hydro-political tension being the most significant factors for dry-season flow, and the risk level of hydro-political tension and basin vulnerability to climate extremes being the most significant for wet-season flow. The results suggest that transboundary cooperation is crucial for managing the impacts of dams on downstream flow, and that various other factors, such as climate, basin characteristics, and socioeconomic indicators, have significant moderating effects on the outcomes. Thus, context-specific approaches are necessary when predicting and managing the impacts of dams on transboundary flow.