Exploring a novel reservoir drawdown operation framework for boosting synergies of hydropower generation and drought defense

Abstract

The seasonal operation of drought-limited water level (DLWL) can efficiently boost the synergies of hydropower production and drought defense. This study proposes a seasonal DLWL operation framework for mimicking reservoir drawdown operation to improve hydropower output and mitigate drought risk. Firstly, three statistical analysis methods were used to divide the drought season into three segments. And then, the simulation model of seasonal DLWL operation was configured to evaluate the effect of reservoir drawdown operation on risk and benefits. Lastly, the combined distance-based assessment method was employed to identify the best scheme of seasonal DLWL operation. The Three Gorges Reservoir sited in the Yangtze River of China constitutes the case study. The results suggested that the proposed framework could facilitate reservoir drawdown operation to achieve 2346.95 million kW·h (7.0% improvement) in annual hydroelectricity production and 3.3% improvement in annual utilization efficiency of water resources, while could reduce 22.2% in drought risk during the dry year, compared with the annual DLWL operation scheme. This study not only can provide scientific and technical support for reservoir drawdown operation benefiting synergies of hydropower generation and drought defense but also can suggest policymakers with various favorable strategies to experience potential risks and benefits of seasonal DLWL operation in the interest of sustainable hydropower development.