However, salt tide, a phenomenon in which the lower course of a river becomes salty when discharge is low during the dry season, struck the lower course of the Pearl River in the winter of 2003.

The salinity in reservoirs exceeded 10,000 degrees, far beyond the national standard of 250 degrees, posing a huge threat to human health, crop growth and industrial production.

To handle the crisis, meetings were held to pool wisdom from government water departments, hydropower stations and power companies.

In 2005, a gigantic trans-provincial project was conducted to divert fresh water from reservoirs located at the upper reaches of the Xijiang river to dilute the salty downstream.

The complexity of the project was beyond everyone's expectations. But the attempt proved successful as a total of 850 million cubic meters of water traveled 1,300 km south, ending the water shortage facing residents of Zhuhai and Macao.