Situation, strategy and enlightenment of emergency water regulation of suppressing saltwater and replenishing freshwater in the Pearl River during the dry seasons in recent 20 years

Over the past 20 years, the Pearl River Basin has faced uneven spatiotemporal distribution of water inflow, alternating floods and droughts, and frequent saltwater intrusion, leading to complex and variable hydrological conditions. The emergency water supply scheduling during the dry season for salinity suppression and freshwater replenishment has become a crucial measure to address water supply and demand contradictions and ensure water security for urban and rural areas in the basin. This paper analyzes the overall situation of emergency water regulation for salinity suppression and freshwater replenishment during dry seasons in the Pearl River Basin over the past two decades, explores the challenges encountered in this emergency water regulation practice, summarizes the overall layout of scheduling engineering systems at different stages, and categorizes the corresponding scheduling strategies adopted. Aiming at potential future water supply risks, the paper proposes forward-looking adaptive control strategies from aspects such as optimizing the layout of water resource allocation projects and the optimal regulation of reservoir groups.