A ferry evacuates residents from an island in Jiujiang, Jiangxi province, on Monday. The island, in the lower reaches of the Yangtze River, has been threatened by surging water levels. [ZHANG ZIWANG/FOR CHINA DAILY]

Authorities have warned of the possibility of major floods in China's northern areas as inundations continue to cause serious damage in many parts of the southern half of the country, especially along the Yangtze River's middle and lower reaches.

Since June, high-water alerts have been triggered along 433 rain-swollen rivers. Only 11 are in the Yellow River Basin in the north, while all others are in southern areas, said Ye Jianchun, vice-minister of water resources, at a news conference organized by the State Council Information Office in Beijing on Monday.

While high water levels linger in the Yangtze and Taihu Lake, more rain than normal is expected in some northern areas as the region prepares to enter its rainy season, usually from late July to early August, he said.

Major floods may occur in the Songhua, Liaohe, Haihe and Huaihe river basins and the middle reaches of the Yellow River, Ye added.

"There has been no flooding in these river basins for years. People are not very knowledgeable about flood control there, and local flood control capabilities are comparatively weak," Ye said.

The ministry will guide northern regions in rolling out precautionary measures as it continues to contribute to efforts in the south, he said.

"The current flood control situation in Yangtze and Taihu remains grim," he said.

Most of the Yangtze's middle and lower reaches have seen water swell above their warning levels. Meanwhile, the water level in Taihu Lake in the lower Yangtze area is forecast to keep rising and may exceed 4.65 meters, the maximum level that its dikes are designed to hold, Ye said.

On Monday, however, southern areas had a rare rain-free day, according to the National Meteorological Center. Before that, the center had issued new alerts for torrential rains for 40 consecutive days starting June 2. Rain will return to the region, however, from Tuesday to Thursday.

At 8 am on Monday, the level of Poyang Lake, China's largest freshwater lake, reached 22.6 meters. On Sunday, it had surpassed its historic high of 22.52 meters, recorded during the devastating floods of 1998, Jiangxi provincial authorities said. The lake is connected to the Yangtze River water system.

"Though some hydrological stations in Poyang reported higher water levels compared with records in 1998, water levels in major hydrological stations in middle and lower reaches of the Yangtze are currently below those of that year," Ye said.

Vice-Minister of Emergency Management Zheng Guoguang said that even though rainfall in the Yangtze Basin has been 51 percent above normal this year, "the likelihood is not great" that the type of prolonged, concentrated precipitation that happened in 1998 will occur.

Also, with construction of more water conservancy projects and an improved system to handle floodwaters, "we have had much stronger flood control capability", he said.