Four rounds of downpours are expected to batter the middle and lower reaches of the Yangtze River later this month, Yangtze flood control and drought relief headquarters said Monday.

The first storm is forecast to hit the river's lower reaches from Wednesday to Saturday, while another three storms are expected by the end of July, a headquarters spokesperson said at a news conference on Monday.

Since China's flood season began in March, downpours and floods have affected 10 provinces and regions that are home to 49.19 million people.

Moreover, a total of 161 people have been killed in floods and 61 were missing as of Sunday, while flooding has caused an estimated 103 billion yuan ($15 billion) in damage, according to flood relief officials.

They also called for unflagging efforts to battle the floods, which are common in late July and early August.

The middle and lower reaches of the Yangtze and the northeastern part of Southwest China's Sichuan Province are likely to receive 20 percent more precipitation between July and September than usual, according to forecasts.

In the Yangtze Basin, water levels in nearly 140 rivers and at over 200 hydrologic stations surpassed warning levels this year, while record-high floods took place in 21 rivers and at 21 stations, said Chen Min, deputy director of flood relief headquarters.

Chen added that water levels in the main branches of the Yangtze also surpassed warning levels for the first time since 1999.