Practice and thinking on "Three Defense Lines" of water supply system regulation in the Pearl River Basin during 2022-2023 dry season

During 2022-2023 dry season, the Pearl River Basin had been affected by insufficient rainfall and runoff, and then the Xijiang River had suffered an extraordinary dry year. With the decrease of runoff, the saltwater intrusion in the estuary became serious, which directly threatened the water supply security of urban and rural residents in Macao, Zhuhai and other places. By strengthening the By strengthening three defense lines of water supply system and implementing eight emergency water supply regulation of freshwater supplement, the saltwater intrusion in the estuary was effectively suppressed, and the probability of fresh water extraction from downstream river was increased, which effectively ensure the water supply security of urban and rural area. This paper summarizes the regulations of three defense lines of water supply system during 2022-2023 dry season of the Pearl River, and some thoughts on the emergency water replenishment of saltwater prevention and freshwater supplement, so as to provide experience reference for the future practice of drought prevention and water supply.