• 한국수자원학회논문집
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• 제40권4호
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• pp.335-343
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• 2007

가뭄에 대한 대책을 수립하기 위해서는 가뭄의 심도 및 지속기간 등 가뭄특성을 산정하여 가뭄을 정량화하는 것이 필요하다. 본 연구에서는 표준강수지수(SPI)를 도입하여 가뭄특성을 정량적으로 산정하였다. 가뭄은 일정기간 지속되는 특성을 지니고 있기 때문에 일정 관측기간동안 제한된 가뭄사상을 가지게 된다. 본 연구에서는 조선시대에 기록된 측우기 자료(1770년 ${\sim}$ 1907년)를 이용하여 관측자료를 확장하였고, 이를 이용하여 보다 많은 가뭄특성자료를 획득하여 가뭄빈도해석을 실시하였다. 측우기 자료와 관측자료를 이용하여 산정된 SPI로부터 절단수준법 개념을 이용하여 SPI의 -1이하를 가뭄으로 정의하고, 가뭄 심도 및 가뭄 지속기간을 구하였다. 가뭄의 심도와 지속기간은 가뭄을 특성화하는데 있어서 중요한 인자로서 최근 이 두 특성을 함께 고려하는 빈도해석법들이 제안되고 있다. 기존의 단일변수 빈도해석을 가뭄에 적용하였을 경우, 가뭄의 심도와 지속기간을 이용하여 구한 각각의 재현특성이 상이하게 나타나는 경우가 있는데, 이는 하나의 가뭄사상의 재현특성을 표현하는데 적절하지가 않다. 본 연구에서는 이변수 감마분포를 이용하여 가뭄심도와 지속기간의 결합확률밀도함수를 추정하고, 이를 통하여 가뭄의 이변수 재현 기간을 산정하여 분석하였다.

• 상하수도학회지
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• 제34권5호
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• pp.335-344
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• 2020

Due to global climate change, mega-droughts have occurred frequently. Since long-term droughts make it difficult to secure the water resources, water supply needs to be restricted in a reasonable manner. In the event of limited water supply, the waterworks need to develop a restricted water supply strategy. This study showed that analyzing daily water supply could be used to respond to the first stage of a drought. According to an analysis of Korea's major water authorities, there was about 7~21% of room for daily minimum water supply in case of a drought. Restricting the water supply by lowering pressure is a good strategy for local water authorities with high water leakage rate since leakage is inversely dependent with pressure. For this method, it is necessary to quantify water deficiency and pressure at each node using a simulation. Since DDA-based software is not possible to predict changes in demand at nodes with pressure reduction, WaterGEMS, a PDA software, was used to quantitatively predict water shortages and pressures at each node. Locations where water is deficient need to install booster pumps or to be dispatched with water tank truck and bottled water. Without these support, lowering pressure could not be an option for water works. This paper suggests a method for waterworks to plan a drought by lowering pressure to restrict water supply using daily water supply analysis and PDA based simulation.

• 대기
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• 제20권2호
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• pp.173-186
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• 2010

The impact of the precipitation has been focused on losses in social and economical sectors. However, as growing the concerns of the future water shortage caused by the climate change, the precipitation should be consider in various views for an effective planning in the water resource management. A precipitation case occurred from 20 to 21 April 2009 was recorded as a welcome rain because it reduced the severe drought continued in Korea from winter season of 2008. In this study, economic values of the event was calculated with positive aspects in various sectors. The estimation is based on four major parts such as a secure of water resources, the improvement of air quality, the decrease of forest fires, and the reduction of the drought impact. The water resources only considered inflow waters into dams and the reservoirs managed by Korean public institutions and their economic values accounts for 5.92 billion won. Decreases of four air pollutants($PM_{10}$, $NO_2$, CO, and $SO_2$) were considered as the positive effects of the rainfall and estimated 175.4 billion won. The preventive effect of the forest fire after the rainfall results in 0.48 billion won. Finally, the rainfall during the drought period is effective to reduce the social costs of 108.65 billion won. Although the economic values estimated in this study explain parts of the positive effects of the precipitation, it can help to develop a comprehensive and systematic valuation system for the whole process of the precipitation. For doing this, various rainfall types should be analyzed in social-economic terms including economics, environments and hydrology.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.166-166
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• 2023

Compound hazards (CHs) are two or more extreme climate events combined which occur simultaneously in the same region at the same time. Compared to individual hazards, the combination of hazards that cause CHs can result in greater economic losses and deaths. While several extreme climate events have been recorded across Asia for the past decades, many studies have only focused on a single hazard. In this study, we assess the spatiotemporal pattern of dry compound hazards which includes drought, heatwave, fire and wind across Asia for the last 42 years (1980-2021) using the historical data from ERA5 Reanalysis dataset. We utilize a daily spatial data of each climate event to assess the occurrence of such compound hazards on a daily basis. Heatwave, fire and wind hazard occurrences are analyzed using daily percentile-based thresholds while a pre-defined threshold for SPI is applied for drought occurrence. Then, the occurrence of each type of compound hazard is taken from overlapping the map of daily occurrences of a single hazard. Lastly, a multivariate assessment are conducted to quantify the occurrence frequency, hotspots and trends of each type of compound hazard across Asia. By conducting a multivariate analysis of the occurrence of these compound hazards, we identify the relationships and interactions in dry compound hazards including droughts, heatwaves, fires, and winds, ultimately leading to better-informed decisions and strategies in the natural risk management.

• 한국수자원학회논문집
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• 제50권10호
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• pp.691-701
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• 2017

본 연구에서는 장기예보자료 기반의 장기 가뭄전망정보를 산정하고, 2015년 가뭄사상을 대상으로 활용성을 평가하였다. 이를 위해 ASOS 59개 지점의 관측강수량, GloSea5의 미래예측 및 과거재현 자료를 활용하였으며, 다양한 지속기간(3, 6, 9, 12개월)에 대한 SPI를 산정하였다. 또한 예보선행시간(1~6개월)에 따른 SPI와 관측자료 기반의 SPI 간의 ROC (Receiver Operating Characteristic)및 통계적 분석(상관계수, 평균제곱근 오차)을 수행하여 전망정보의 활용성을 평가하였다. ROC 분석결과, SPI(3)는 2개월, SPI(6)은 3개월, SPI(9)는 4개월, SPI(12)는 5개월까지 ROC score 약 0.70 이상으로 산정되었다. 예보선행시간별 상관계수 및 평균제곱근오차의 경우, 2개월 선행시간 SPI(3)은 0.60, 0.87, 4개월 선행시간 SPI(6)은 0.72, 0.95, 5개월 선행시간 SPI(9)는 0.75, 0.95, 6개월 선행시간 SPI(12)는 0.77, 0.89로 상관계수는 높게, 평균제곱근오차는 낮게 산정되어 활용성이 있는 것으로 판단된다.

• Korean Journal of Hydrosciences
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• 제10권
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• pp.35-46
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• 1999

An integrated system of GIS and water quality model was suggested including the pollutant loads from the watershed. The developed system consits of two parts. First part is the information on landuse and several surface factors concerning the overland flow processes of water and pollutants. Second part is the modeling modules which include storm event pollutant load model(SEPLM), non-storm event pollutant load model(NSPLM), and river water quality simulation model(RWQSM). Models can calculate the pollutant load from the study area. The databases and models are linked through the interface modules resided in the overall system, which incorporate the graphical display modules and the operating scheme for the optimal use of the system. The developed system was applied to the Chungju multi-purpose reservoir to estimate the pollutant load during the four selected rainfall events between 1991 and 1993, based upon monthly basis and seasonal basis in drought flow, low flow, normal flow and wet flow.

• 한국수자원학회논문집
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• 제51권spc1호
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• pp.1117-1126
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• 2018

용수공급시스템은 용수를 안정적으로 확보하여 사용자의 수요량을 충족시키는 것을 목표로 하지만, 평년보다 적은 유입량으로 인해 정상공급에 실패하는 경우가 발생한다. 그러나 강수의 부족으로 발생하는 가뭄 상황이 언제나 용수공급 실패를 유발하는 것은 아니기 때문에, 용수공급에 대한 안전도를 산정할 때 실질적인 용수 부족 사상의 특성을 고려할 필요가 있다. 이를 위해 본 연구에서는 이수안전도 평가 지표로 주로 사용되는 신뢰도와 취약도를 이용하여 결합 가뭄관리지수(JDMI)를 개발하였으며, 이를 바탕으로 미래 용수공급 위험도를 산정하였다. 미래에 대한 분석을 위해 RCP 4.5 및 8.5 시나리오에 대하여 GCM으로부터 생산된 기후변화 시나리오 자료를 적용하고 미래 기간을 21세기 전기, 중기, 및 후기로 구분하였다. JDMI를 기반으로 낙동강 유역의 용수공급 위험도를 분석한 결과 RCP 4.5 시나리오에서 RCP 8.5 시나리오보다 위험도가 더 높은 것으로 분석되었다. 용수공급 취약지역은 RCP 4.5에서는 남강댐(W18)으로 나타났으며, RCP 8.5에서는 형산강(W23)과 낙동강남해(W33) 유역으로 분석되었다.

• Weed & Turfgrass Science
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• 제3권2호
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• pp.130-136
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• 2014

Tall fescue is commonly well-adapted for low maintain area because of its wear resistance, deep root system, and drought tolerances. Deep and infrequent irrigation refers to applying large amounts of irrigation, 1.3 to 2.5 cm or more, in a single irrigation event. Light and frequent irrigation is commonly used with small amounts of water, 0.3 to 0.6 cm, every day or every other day. N use for turfgrass management is often unnoticed for water management. The objective of this field study was to evaluate the effects of irrigation frequency and N rates for tall fescue growth. The three irrigation treatments were no irrigation (precipitation only), 0.5 cm applied every other day, and 1.8 cm applied once a week at one irrigation event. The nitrogen (N) treatments were the low, medium, and high N rate treatments. The low, medium, and high N treatments were applied over 2, 4, and 6 applications, respectively. If high main maintenance of tall fescue is not important and water source is limited, irrigation is not necessary and, the $9.8gNm^{-2}yr^{-1}$ of two applications can be recommended for tall fescue under the weather condition of the study.

• 환경영향평가
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• 제18권6호
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• pp.347-357
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• 2009

This study conducted a vulnerability assessment on Korea's physical infrastructure to provide base data for developing strategies to strengthen Korea's ability to adapt to climate change. The assessment was conducted by surveying professionals in the field of infrastructure and climate change science. A vulnerability assessment was carried out for seven climate change events: average temperature increases, sea level rise, typhoons and storm surges, floods and heavy rain, drought, severe cold, and heat waves. The survey asked respondents questions with respect to the consequences of each climate change event, the urgency of adaptation to climate change, and the scale of investment for adaptation to each climate change event. Thereafter, management priorities for infrastructure were devised and implications for policy development were suggested. The results showed that respondents expected the possibility of "typhoons and storm surges" and "floods and heavy rain" to be the most high. Respondents indicated that infrastructure related to water, transportation, and the built environment were more vulnerable to climate change. The most vulnerable facilities included river related facilities such as dams and riverbanks in the "water" category and seaports and roads in the "transport and communication" category. The results found were consistent with the history of natural disasters in Korea.

• 한국농공학회논문집
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• 제62권4호
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• pp.1-12
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• 2020

The extreme 2017 spring drought affected a large portion of South Korea in the Southern Gyeonggi-do and Chungcheongnam-do districts. This drought event was one of the climatologically driest spring seasons over the 1961-2016 period of record. It was characterized by exceptionally low reservoir water levels, with the average water level being 36% lower over most of western South Korea. In this study, we consider drought response methods to alleviate the shortage of agricultural water in times of drought. It could be to store water from a stream into a reservoir. There is a cyclical method for reusing water supplied from a reservoir into streams through drainage. We intended to present a decision-making plan for water supply based on the calculation of the quantity of water supply and leakage. We compared the rainfall-runoff equation with the TANK model, which is a long-term run-off model. Estimations of reservoir inflow during non-irrigation seasons applied to the Madun, Daesa, and Pungjeon reservoirs. We applied the run-off flow to the last 30 years of rainfall data to estimate reservoir storage. We calculated the available water in the river during the non-irrigation season. The daily average inflow from 2003 to 2018 was calculated from October to April. Simulation results show that an average of 67,000 tons of water is obtained during the non-irrigation season. The report shows that about 53,000 tons of water are available except during the winter season from December to February. The Madun Reservoir began in early October with a 10 percent storage rate. In the starting ratio, a simulated rate of 4 K, 6 K, and 8 K tons is predicted to be 44%, 50%, and 60%. We can estimate the amount of water needed and the timing of water pump operations during the non-irrigation season that focuses on fresh water reservoirs and improve decision making for efficient water supplies.