Drought resistance of dams based on propagation analysis: A case study of various multipurpose dams in South Korea

Study region: Nine major multipurpose dam basins in South Korea Study focus: The foundation for quantitatively evaluating the drought resistance of dams is still insufficient. In this study, we targeted multipurpose dams in Korea, identified meteorological drought (MD), hydrological drought in the natural state (HDn, drought under the assumption that no dam exists), and hydrological drought in the adjusted state (HDa, drought under the assumption that the dam is in a regulated state), and then sought to quantify the drought resistance of dams based on propagation analysis. New hydrological insights from the region: When drought events propagated from HDn to HDa, we found that the number of drought events decreased, the duration shortened, and the intensity of droughts tended to weaken. Among the nine dams analyzed, six exhibited high levels of drought propagation resistance. However, due to differences in dam design parameters, operational practices, and the topographical characteristics of the catchment areas, the remaining two dams showed relatively low resistance, and the final dam actually exacerbated drought conditions. The methodology proposed in this study, which involves estimating drought propagation time and delay time and analyzing the α-shape through bivariate frequency analysis, can serve as a standard tool for quantitatively evaluating the drought resistance of dams.