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Research Article

Hydrological drought projections in the five major river basins of South Korea under AR6 climate change scenarios

AR6 기후변화 시나리오 기반 한국 5대강 유역의 수문학적 가뭄 전망

Jaeyoung Kima
,
Moon Hwan Leeb*
,
Jongho Ahnc
김 재영a
,
이 문환b*
,
안 종호c
aVisiting Research Fellow, Water Management Division, Land and Environment Research Group, Korea Environmental Institute, Sejong, Korea
bSenior Research Fellow, Water Management Division, Land and Environment Research Group, Korea Environmental Institute, Sejong, Korea
cChief Research Fellow, Water Management Division, Land and Environment Research Group, Korea Environmental Institute, Sejong, Korea
a한국환경연구원 국토환경연구본부 물관리연구실 초빙연구원
b한국환경연구원 국토환경연구본부 물관리연구실 연구위원
c한국환경연구원 국토환경연구본부 물관리연구실 선임연구위원
*Corresponding Author
31 March 2026. pp. 269-283
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Abstract

This study aims to project future runoff and drought conditions in South Korea’s five major river basins under AR6-based climate change scenarios. By simultaneously analyzing changes in runoff and drought across all basins, this study overcomes the fragmentation of previous research caused by differences in study regions, time periods, and methodologies, and enables direct comparison of regional changes under consistent criteria and conditions. Out of 20 climate change scenarios provided by the Korea Meteorological Administration (KMA), seven were selected, and a hydrological model was applied to simulate runoff. Based on the projected runoff, the Standardized Runoff Index (SRI) was calculated to assess drought characteristics. For the reference period (1991-2020) and two future periods (2031-2060 and 2061-2090), changes in mean runoff, coefficient of variation (CV) of runoff, and drought frequency, intensity, and duration were evaluated. The results indicate that future runoff will increase in all basins except the Geum River Basin, suggesting a potential expansion of water resources, with the Seomjin River Basin showing the largest increase in the far future (+20.2% compared to the reference). Nationwide, the CV of runoff is projected to increase by approximately 15% in both future periods, implying a partial decline in hydrological stability, although the magnitude of change is relatively small. Drought frequency is projected to decrease in most basins; however, the Geum and Yeongsan River Basins are projected to experience significant increases (+70.8% and +20.7%, respectively) in the far future. Drought intensity is generally projected to worsen, except in the Seomjin River Basin (-3.3%). Drought duration is projected to decline in most basins, with the Geum River Basin being the only exception (+8.3%). Overall, the Geum River Basin is identified as the most vulnerable, with increases in drought frequency, intensity, and duration. In addition, this study compared the results with previous AR4- and AR5-based studies and recent regional studies conducted using AR6 scenarios to analyze the consistency and differences arising from scenario generations and spatial scales. The comparison shows that although some differences exist depending on the scenarios and study regions, an overall increasing trend in precipitation and runoff is consistent, while drought risks are projected to intensify in specific regions. These findings emphasize the necessity of regionally tailored approaches for climate change adaptation. By providing a quantitative assessment of hydrological and drought variability at both national and basin scales, this study offers critical baseline information for developing national climate change adaptation strategies and basin-specific water resource management plans.

Keywords
Climate change
Drought
Runoff
Five River Basins
SWAT
SRI

본 연구는 AR6 기반 기후변화 시나리오를 활용하여 우리나라 5대강 유역의 미래 유출량과 가뭄 변화를 전망하고자 한다. 또한, 전국 5대강 유역의 유출량과 가뭄 변화를 동시에 비교 분석함으로써, 기존 연구에서 지역, 시기, 방법론의 차이로 인해 산재되어 있던 한계를 극복하고, 동일한 기준과 조건하에서 지역 간 변화를 직접적으로 비교하였다. 기상청에서 제공하는 20종의 기후변화 시나리오 중 7개를 선정하여 수문모형으로 유출량을 산출하였고, 이를 바탕으로 표준유출지수(Standardized Runoff Index, SRI)를 계산하여 가뭄 특성을 분석하였다. 기준기간(1991-2020년)과 두 개의 미래기간(2031-2060년, 2061-2090년)에 대해 유출량, 유출량 변동계수, 가뭄의 빈도·강도·지속기간의 변화를 비교하였다. 분석 결과, 금강 유역을 제외한 모든 유역에서 미래 유출량이 증가하였으며, 섬진강 유역은 먼 미래에 +20.2%로 가장 큰 증가를 보였다. 그러나 유출량 변동계수는 전국 약 15% 이상 증가하여 수문 체계의 안정성이 일부 저하될 가능성이 나타났다. 가뭄 분석에서는 대체로 빈도가 감소하였으나, 금강 유역과 영산강 유역은 빈도가 각각 +70.8%, +20.7% 증가하는 것으로 전망되었다. 가뭄 강도는 섬진강 유역의 일부 지역을 제외하고 대부분 심화될 가능성이 높았으며, 가뭄 지속기간은 대부분 유역에서 감소하였으나 금강 유역은 +8.3% 증가하였다. 종합적으로 금강 유역은 가뭄 발생 빈도, 강도, 지속기간이 모두 증가하여 향후 가뭄에 가장 취약한 유역으로 평가되었다. 또한, 본 연구 결과를 기존 AR4·AR5기반 유사 연구 및 최근 일부 지역에서 수행된 AR6 연구와 비교하여, 시나리오 세대 및 공간 범위 차이에 따른 일관성과 차이점을 분석하였다. 분석 결과, 논문에서 사용된 기후변화 시나리오와 지역에 따라 전망 결과의 일부 차이는 있지만, 전반적으로 강수량과 유출량의 증가가 일관되게 전망되는 반면 지역에 따라 가뭄의 위험이 증가된다는 것을 도출하였다. 이러한 결과는 기후변화 적응 전략의 지역 맞춤형 접근이 필요하다는 것을 시사하며, 국가 차원의 기후위기 적응 전략 수립과 유역별 맞춤형 수자원 관리 대책 마련을 위한 기초자료로 활용이 가능하다.

키워드
기후변화
가뭄
유출량
5대강 유역
SWAT
SRI
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Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 59
  • No :3
  • Pages :269-283
  • Received Date : 2025-11-15
  • Revised Date : 2026-01-18
  • Accepted Date : 2026-01-19
  • DOI :https://doi.org/10.3741/JKWRA.2026.59.3.269
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