Reservoir operation affects propagation from meteorological to hydrological extremes in the Lancang-Mekong River Basin

Xiaobo Yun; Qiuhong Tang; Jie Wang; Jiabo Li; Yumei Li; Hongjun Bao

doi:10.1016/j.scitotenv.2023.165297

Reservoir operation affects propagation from meteorological to hydrological extremes in the Lancang-Mekong River Basin

Sci Total Environ. 2023 Oct 20:896:165297. doi: 10.1016/j.scitotenv.2023.165297. Epub 2023 Jul 3.

Authors

Xiaobo Yun¹, Qiuhong Tang², Jie Wang³, Jiabo Li⁴, Yumei Li¹, Hongjun Bao¹

Affiliations

¹ National Meteorological Centre, China Meteorological Administration, Beijing, China; China Meteorological Administration Hydro-Meteorology Key Laboratory, Beijing, China.
² Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China. Electronic address: tangqh@igsnrr.ac.cn.
³ College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China.
⁴ Department of Civil Engineering, University of Tokyo, Tokyo, Japan.

PMID: 37406697
DOI: 10.1016/j.scitotenv.2023.165297

Abstract

Hydrological extremes intensified by meteorological extremes are threatening water security in the Lancang-Mekong River Basin (LMRB), and reservoir operation may mitigate hydrological extreme through regulating hydrological processes during meteorological extreme. However, the capacity of reservoirs in modulating propagation from meteorological extremes to hydrological extremes has seldom been quantified. This study adopted the VIC-Reservoir hydrological model to assess the impact of reservoir operation on the propagation at multi-timescales in the LMRB. The Standardized Precipitation Index and Standardized Streamflow Index were adopted to characterize meteorological extreme and hydrological extreme, respectively, on a range of timescales. The results indicate that reservoir operation has effectively delayed the propagation from meteorological to hydrological extremes during the period of 2008-2016 with rapid reservoir development in the LMRB, compared with the period of 1984-2007 with natural condition. The transmission process of extreme events with a duration of no more than 6 months has been suppressed during the reservoir impact period. However, the influence of reservoir regulation on long-term extreme events that last more than 12 months is generally low. In the upstream basin where reservoir impact is largest, reservoirs can exert a weak mitigation effect on long-term dry extremes. This study provides quantitative assessment of the role of reservoirs in regulating propagation between meteorological and hydrological extremes in the LMRB, and facilitate decision making for the management of water hazards under changing environment.

Keywords: Hydrological extreme; Meteorological extreme; Reservoir operation; The Lancang-Mekong River Basin.