Guarantee the water supply security for Macao and Zhuhai and promote the high-quality development of the Greater Bay Area—The 20th anniversary achievement of emergency water regulation for resisting saltwater and supplementing freshwater in the Pearl River

Since the 21st century, the increasing salty tide in the Pearl River Estuary have seriously threatened the urban water security in the Guangdong-Hong Kong-Macao Greater Bay Area. Since 2004, the Ministry of Water Resources has organized the the Pearl River Water Resources Commission to successfully implement the emergency water regulation of saltwater suppressing and freshwater replenishing in the the Pearl River for 20 consecutive years, which has effectively guaranteed the water supply safety of the city groups in the Guangdong-Hong Kong-Macao Greater Bay Area such as Macao and Zhuhai cities. This paper expounds the development process of 20 years' emergency water regulation of saltwater suppressing and freshwater replenishing from the aspects of strategic thinking, engineering systems, technical means and institutional mechanism, sorts out the main successful experiences, and looks forward to improving the water supply security capacity of the the Pearl River Basin.