With water in Taihu Lake swelling to the maximum design level for its dikes, and the development of a second flood in the Yangtze River, the flood control situation turned grimmer simultaneously in both the upper and lower reaches of Asia's longest river on Friday.

Water resources authorities have demanded efforts to strengthen coordination of major water conservancy projects along the Yangtze, such as the Three Gorges Dam, to cope with the situation.

As a result of incessant downpours, at 7 am on Friday, the average water level of Taihu, the third largest freshwater lake in China, reached 4.65 meters－the upper limit that can ensure the safety of its embankments and affiliated projects－according to the Taihu Basin Authority of the Ministry of Water Resources. The highest water level of the lake was 4.97 meters in 1999.

"The water level is expected to continue to rise and remain high for an extended period of time," an official release said. "The lake's flood control situation is extremely grim."

The emergency response for flood control in the Taihu Basin was upgraded on Friday to Level I, the highest in a four-tier emergency response system. Meanwhile, the water resources department of Jiangsu province, where most of the lake is located, issued the highest alert for flooding in the lake.

The water level of the lake had stayed above the point that triggers an alert for 19 days. The current water level means that "a major flood has occurred in the Taihu Basin", according to the Ministry of Water Resources.

Local authorities have been required to intensify patrols of dikes while ratcheting up the discharge of water conservancy projects near Taihu. So far, 14,700 people have participated in the patrols.

Also on Friday, the second flood of the Yangtze River developed. At 10 am, floodwaters began to pour into the Three Gorges reservoir at a rate of 50,000 cubic meters per second.

The rate was forecast to reach 55,000 cubic meters per second at 8 pm on Friday, according to Changjiang Water Resources Commission, Yangtze's management authority.

The first flood this year arrived at the dam on July 2 with a peak flow rate of 53,000 cubic meters per second.

E Jingping, minister of water resources, has demanded the coordination of reservoirs be ramped up to relieve Taihu of pressure from upstream.

He said the Three Gorges Dam has played an important role in stopping floodwaters and tempering the flood peak this year.

In the face of a continuous large inflow, he required management authorities to arrange water discharges "in a scientific manner".

Setting of the discharge rate should take into consideration the reservoir's safety and carrying capability, the conditions of dikes affected by high water levels downstream and the carrying capacity of river courses, he stressed at a conference on Thursday.

A total of 23 reservoirs in the upper and middle reaches of the Yangtze have been mobilized to help store water. In total, they could store 13 billion cubic meters of floodwaters, according to the ministry.