Study on the climate impacts on the reservoir waterlevel

Abstract

Climate change poses significant challenges to the stability of hydropower systems, and the increased frequency of extreme weather events due to global warming further exacerbates these challenges. To reduce the climate vulnerability of hydropower systems, this study assessed the impact of temperature and precipitation variations on reservoir water level dynamics. Using daily water level data from 17 reservoirs in Sichuan Province, China, this study enhanced a benchmark model by incorporating nonlinear functions that more realistically represent actual conditions than linear functions. Within a linear regression framework, this study incorporated quadratic terms for temperature and precipitation. This constructed a model that accurately quantifies the relationship between climatic factors and the first-order difference of reservoir water level. The results demonstrate that both temperature and precipitation significantly and nonlinearly drive reservoir water level fluctuations. This study successfully characterized the complex relationship between water level fluctuations and climatic variables using a quadratic function and performed an in-depth analysis of the Marginal Rate of Substitution (MRS) between temperature and precipitation. A key finding reveals that the MRS exhibits dynamic dependency, with its numerical values and trends depending on specific temperature and precipitation levels. A turning point in the MRS trend occurs when precipitation reaches 17 centimeters and the temperature is 13.5 °C, which is a critical point for reservoir managers to monitor. Against the backdrop of global climate change threatening water security, this study quantitatively uncovers the dynamic nonlinear coupling mechanisms between climatic factors and reservoir water level. The identified critical tipping points offer deeper insights into climate impacts on reservoir operations, carrying significant theoretical and practical implications for building resilient, sustainable water resource management systems and optimizing hydropower system operations.