Lee et al. (2026) Drought resistance of dams based on propagation analysis: A case study of various multipurpose dams in South Korea

Identification

• Journal: Journal of Hydrology Regional Studies
• Year: 2026
• Date: 2026-01-09
• Authors: Chaelim Lee, Sera Kang, Sangdan Kim
• DOI: 10.1016/j.ejrh.2026.103106

Research Groups

• Division of Earth Environmental System Science (Major in Environmental Engineering), Pukyong National University, Republic of Korea
• Water Resources & Environmental Research Center, K-water Research Institute, Republic of Korea

Short Summary

This study quantitatively evaluates the drought resistance of nine major multipurpose dams in South Korea by analyzing the propagation of meteorological drought (MD) to hydrological drought in natural (HDn) and dam-adjusted (HDa) states. It found that dams generally mitigate drought duration and intensity, with six out of nine dams showing high resistance, while others exhibited low resistance or even exacerbated drought conditions.

Objective

• To analyze the process by which meteorological drought propagates into hydrological drought regulated by dam operations.
• To quantitatively evaluate the drought mitigation effect (drought resistance) of dams and compare drought resistance between dams.
• To establish evaluation criteria for the role of dams in drought response for major multipurpose dams in Korea.

Study Configuration

• Spatial Scale: Nine major multipurpose dam basins across four river regions (Han, Nakdong, Geum, Seomjin-Yeongsan) in South Korea.
• Temporal Scale: Data periods varying from 23 to 49 years for individual dams, with weather station data having more than 35 years of continuous records.

Methodology and Data

• Models used:
  • Standardized Precipitation Index (SPI) for meteorological drought (MD).
  • Standardized Runoff Index (SRI) for hydrological drought in natural (HDn) and adjusted (HDa) states.
  • Run theory (threshold ≤ -1.0) and Inter-Event Time Definition (IETD = 30 days) for drought event identification.
  • Hybrid Lk-based approach for drought propagation time and delay time estimation.
  • Univariate frequency analysis for return periods.
  • Nagano–Kadoya bivariate exponential distribution for bivariate frequency analysis of duration and intensity.
  • Integrated Drought Resistance Curve (IDRC) for comprehensive drought resistance assessment.
• Data sources:
  • Daily dam inflow and outflow data from the Water Resources Management Information System (www.wamis.go.kr) operated by the Ministry of Environment of the Republic of Korea.
  • Daily precipitation data from the Automated Synoptic Observing System (ASOS) provided by the Korea Meteorological Administration.

Main Results

• The average annual number of drought events decreased from MD to HDn, and further decreased from HDn to HDa, indicating dam regulation reduces drought frequency.
• Drought duration generally increased from MD to HDn but decreased from HDn to HDa, resulting in shorter durations for HDa compared to MD in most cases (8 out of 9 dams).
• Drought intensity generally decreased from MD to HDn and further from HDn to HDa (6 out of 9 dams), but some dams showed intensified HDa.
• Drought propagation time to HDa was longer than to HDn for most dams, and drought delay time was consistently longer or equal for HDa, indicating dams delay hydrological responses.
• Bivariate frequency analysis showed that six out of nine dams exhibited significant resistance to drought propagation, with the return period of average drought events in HDa being 7 % to 90 % shorter than in HDn.
• However, the Namgang Dam (NGD) and Hapcheon Dam (HCD) showed less significant resistance, and the Seomjin Dam (SJD) exacerbated drought conditions, increasing its return period from 12.7 years to 180.8 years.
• The Integrated Drought Resistance Curve (IDRC) revealed that most dams are effective against relatively mild drought events, but their resistance weakens or disappears as drought intensity increases.

Contributions

• Proposes a novel hybrid methodology combining event-based and correlation analysis (Lk-based) to more accurately estimate drought propagation and delay times by removing non-drought period noise.
• Introduces the concept of drought event propagation rate and propagation index to quantify changes in drought characteristics (number, duration, intensity) due to dam operations.
• Develops an Integrated Drought Resistance Curve (IDRC) based on bivariate frequency analysis of duration and intensity, allowing for a comprehensive, quantitative, and drought-level-dependent assessment and comparison of dam drought resistance.
• Provides a quantitative assessment of the actual effectiveness of dam operations in mitigating drought based on historical measured data, distinguishing natural variability from artificial regulation effects.
• Identifies key watershed characteristics (bifurcation ratio, main-channel density) influencing the propagation from meteorological to natural hydrological drought.

Funding

• Korea Environment Industry & Technology Institute (KEITI) through Water Management Program for Drought Project, funded by Korea Ministry of Climate, Energy and Environment (MCEE) (Reference code: RS-2023–00230286).
• National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (Reference code: RS-2025–00563294).

Citation

@article{Lee2026Drought,
  author = {Lee, Chaelim and Kang, Sera and Kim, Sangdan},
  title = {Drought resistance of dams based on propagation analysis: A case study of various multipurpose dams in South Korea},
  journal = {Journal of Hydrology Regional Studies},
  year = {2026},
  doi = {10.1016/j.ejrh.2026.103106},
  url = {https://doi.org/10.1016/j.ejrh.2026.103106}
}