The Yangtze River, China's longest, will brace for its largest flood peak so far this year due to continuous rainfall upstream, authorities said Friday.

Water flow into the reservoir of the Three Gorges Dam will reach 48,000 cubic meters per second on Sunday, the largest since this year's flood season, said the Yangtze River Flood Control and Drought Relief Headquarters.

Water flow into the reservoir has increased rapidly in the past two days, by 11,000 cubic meters per second. As of 2 p.m. Friday, the water flow hit 34,500 cubic meters per second. The water level of the reservoir stood at about 147.5 meters.

The weather forecast said in the next one to three days, heavy rain will hit the upstream region.

From 12 a.m. Friday, water flow discharged out of the reservoir will be increased to 35,000 cubic meters per second.

As the world's largest hydropower project, the Three Gorges Project consists of a dam, five-tier ship docks and a total of 32 hydropower turbo-generators.