• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.4
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• pp.11-20
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• 2022

Currently, the operation rule of agricultural reservoirs in case of drought events follows the drought forecast warning standard of agricultural water supply. However, it is difficult to preemptively manage drought in individual reservoirs because drought forecasting standards are set according to average reservoir storage ratio such as 70%, 60%, 50%, and 40%. The equal standards based on average water level across the country could not reflect the actual drought situation in the region. In this study, we proposed the improvement of drought operation rule for agricultural reservoirs based on the percentile approach using past water level of each reservoir. The percentile approach is applied to monitor drought conditions and determine drought criteria in the U.S. Drought Monitoring (USDM). We applied the drought operation rule to reservoir storage rate in extreme 2017 spring drought year, the one of the most climatologically driest spring seasons over the 1961-2021 period of record. We counted frequency of each drought criteria which are existing and developed operation rules to compare drought operation rule determining the actual drought conditions during 2016-2017. As a result of comparing the current standard and the percentile standard with SPI6, the percentile standard showed severe-level when SPI6 showed severe drought condition, but the current standard fell short of the results. Results can be used to improve the drought operation criteria of drought events that better reflects the actual drought conditions in agricultural reservoirs.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.323-329
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• 2012

The Standardized Precipitation Index (SPI) is a widely used drought index to provide good estimations of the intensity, magnitude and spatial extent of droughts. The objective of this study was to analyze the spatial pattern of drought by SPI index. In this paper, the patterns of drought hazard in Iran are evaluated according to the data of 40 weather stations during 1967-2009. The influenced zone of each station was specified by the Thiessen method. It was attempted to make a new model of drought hazard using GIS. Three criteria for drought were studied and considered to define areas of vulnerability. Drought hazard criteria used in the present model included: maximum severity of drought in the period, trend of drought, and the maximum number of sequential arid years. Each of the vulnerability indicators were mapped and these as well as a final hazard map were classified into 5 hazard classes of drought: one, slight, moderate, severe and very severe. The final drought vulnerability map was prepared by overlaying three criteria maps in a GIS, and the final hazard classes were defined on the basis of hazard scores, which were determined according to the means of the main indicators. The final vulnerability map shows that severe hazard areas (43% of the country) which are observed in the west and eastern parts of country are much more widespread than areas under other hazard classes. Overall, approximately half of the country was determined to be under severe and very severe hazard classes for drought.

• Journal of Korean Society of Rural Planning
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• v.24 no.4
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• pp.47-55
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• 2018

Currently in the drought evaluation, which is a supplier-oriented standard that applies storage rates of reservoirs, evaluation for users that use agricultural water is not done. Therefore, this study established drought evaluation items for drought evaluation based on farmers' judgement, conducted a survey on farmers and experts, compared and analyzed weighted value between two groups, and then classified the evaluation standards per each evaluation item. The agricultural drought evaluation items are 5 major items of water supply lapse rate, agricultural weather, agricultural irrigation facility, crop and soil, and 12 subsections for regional characteristics and opinions of consumers that use water to be reflected. The result of analyzing weighted value of farmers and experts' major items shows that farmers is agricultural irrigation facility(0.219), water supply lapse rate(0.211), agricultural weather(0.204), crop(0.183) and soil(0.183). Experts is agricultural weather(0.297), agricultural irrigation facility(0.202), water supply lapse rate(0.189), crop(0.162) and soil(0.150), which displays difference between the two groups. The agricultural drought criteria standards are established based on precedent studies and cases, and grades of evaluation items are 1st grade(extreme stage), 2nd grade(warning stage), 3rd grade(alert stage) and 4th grade(attention stage). The above analysis per each consumer-oriented agricultural drought evaluation item and the analysis on the standards of evaluation grades are expected to be used as a basic resource for establishing agriculture drought policy and selecting drought area in the future.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.7-13
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• 2005

There are two ways to mitigate the drought. One is the structural measures such as storage of irrigation water, development of emergency wells, etc. The other one is the nonstructural measures such as water saving management by the early warning system. To precast and evaluate the drought, we need to develop the drought indices for agriculture. In the present drought preparedness plans of Ministry of Agriculture and Forestry (MAF), it is prescribed that the preparedness levels should be classified by considering the precipitation, reservoir storage, soil moisture in paddy and upland, and the growing status of crops. However there are not clear quantitative criteria for consistent judgment. This shows that we have not selected and utilized the proper drought index for agriculture and we did not have the information system to calculate the drought indices periodically and warn the outbreak of the drought. The objectives of the study are to develope of Agricultural Drought Evaluation System and to evaluate this indices for current agricultural status using the system.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.5
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• pp.127-136
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• 2017

The object of this study was to assess availability of meteorological drought index for agricultural dorught estimation in ungauged area of agricultural drought parameters which are reservoir water level and soil moisture. The IADI (Integrated Agricultural Drought Index) and the SPI (Standard Precipitation Index), which are the criteria for determining agricultural drought and meteorological drought, were calculated and compared. For this purpose, the droughts that occurred in the Baeksan reservoir in Gimje and the Edong reservoir in Suwon were evaluated by using the IADI and SPI drought indecies. In addition, we compared and analyzed the depth of drought based on the two drought indices. Evaluations derived form the IADI and SPI showed that the standard precipitation index tended to indicate the occurrence of drought earlier than the integrated agricultural drought index. However, the integrated agricultural drought index was better than the standard precipitation index at evaluating the severity of drought during the period of irrigation. The relationship between these two drought indices seems to be useful for decision making in the case of drought, and it is considered that more studies are needed to examine the applicability of these drought indexes.

• Journal of Korea Water Resources Association
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• v.56 no.10
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• pp.619-629
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• 2023

Recent intensification of climate change has led to an increase in damages caused by droughts. Currently, in Korea, the Standardized Precipitation Index (SPI) is used as a criterion to classify the intensity of droughts. Based on the accumulated precipitation over the past six months (SPI-6), meteorological drought intensities are classified into four categories: concern, caution, alert, and severe. However, there is a limitation in classifying drought intensity solely based on precipitation. To overcome the limitations of the meteorological drought warning criteria based on SPI, this study collected emergency water supply damage data from the National Drought Information Portal (NDIP) to classify drought intensity. Factors of SPI, such as precipitation, and factors used to calculate evapotranspiration, such as temperature and humidity, were indexed using min-max normalization. Coefficients for each factor were determined based on the Genetic Algorithm (GA). The drought intensity based on emergency water supply was used as the dependent variable, and the coefficients of each meteorological factor determined by GA were used as coefficients to derive a new Drought Severity Classification Index (DSCI). After deriving the DSCI, cumulative distribution functions were used to present intensity stage classification boundaries. It is anticipated that using the proposed DSCI in this study will allow for more accurate drought intensity classification than the traditional SPI, supporting decision-making for disaster management personnel.

• KCID journal
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• v.1 no.2
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• pp.22-28
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• 1994

The calculation method for the Drought index based on the principal hydrological factors, such as precipitation, reservoir storage and river discharge, can estimate the duration and intensity of drought. It is not easy to establish an universal criteria o

• KCID journal
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• v.4 no.2
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• pp.48-61
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• 1997

Drought index calculation method using principal hydrological factors, such as precipitation amount and reservoir storage ratio, can estimate the duration and the intensity of drought. It is not easy to establish an universal criteria of drought, since th

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.13-24
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• 2013

Agriculture is affected directly by climate conditions and changes, and it is necessary to understand the impact of climate change on agricultural reservoirs which are the main water resources for paddy fields in Korea. This study aimed to evaluate the impact of climate change on the anti-drought capacity including water supply capability (WSC) and drought response ability (DRA) of agricultural reservoirs based on RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios of CanESM2 (The Second Generation Earth System Model) provided by CCCma (Canadian Center for Climate Modeling and Analysis). The WSC and DRA were estimated using frequency analysis and runs theory. The six reservoirs (Yooshin, Nogok, Kumsung, Songgok, Gapyung, Seoma) were selected considering geographical characteristics and design criteria of reservoir capacity. In case of Seoma reservoir, more than 10 year drought return period (DRP), the variation of the WSC was estimated larger than the others. In case of Yooshin reservior (2~5 DRP) DRC was decreased in 2025s under RCP8.5. These results could be utilized for agricultural reservoirs management and future design criteria considering climate change impacts on paddy irrigation.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.5
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• pp.13-24
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• 2023

Due to recent climate change, the amount of rainfall during the summer season in South Korea has been decreasing, leading to an increase in areas affected by frequent droughts. Droughts have the characteristic of occurring over a wide area and being unpredictable in terms of their onset and end, necessitating proactive research to cope with them. In this study, we conducted an assessment of agricultural drought vulnerability in Taean-gun, Chungcheongnam-do, focusing on irrigation facilities and paddy fields. The assessment criteria were meteorological impact, drought occurrence status, supplementary water supply capacity, and drought response capability, with nine specific indicators selected. The drought response capability was analyzed by applying a scoring system as a key component of the agricultural drought vulnerability assessment, while the other indicators were quantified using an entropy weighting technique. The results of the assessment showed that Anmyeon-eup and Taean-eup were the safest areas, while Wonbuk-myeon, Nam-myeon, and Gonam-myeon were the most vulnerable. It is expected that the findings can be utilized to enhance understanding and proactive measures for coping with agricultural drought, and to determine the priority of drought response in different regions.