Why does Xin 'anjiang flood?

Xin 'anjiang Reservoir has exceeded the flood limit water level and is still rising. The water level required for flood discharge has been reached.

The water level of Xin 'anjiang Reservoir began to rise at 22: 00 104.48 m on July 2, 2020, and reached 106.5 1 m on July 6, 2020, which exceeded the flood limit water level by 0.0 1 m and was still rising. According to the weather forecast at that time, it was predicted that the water level would exceed107m on July 7th, which was also the direct reason for the decision to open three holes for flood discharge on July 6th.

At 2 o'clock on July 7th, heavy rain suddenly fell in Xin 'anjiang reservoir area, reaching the highest water level 108.39 m at 9 o'clock on July 8th, and there was heavy rainfall after the weather forecast. The rapid rise of water level and the subsequent heavy rainfall forecast are the main reasons for the subsequent increase of discharge, so as to ensure the overall consideration of dam safety, downstream personnel safety and basin safety of Xin 'anjiang Reservoir.

Extended data

Flood discharge scheme of Xin 'anjiang Reservoir

The flood discharge of Xin 'anjiang Reservoir is different from that of other reservoirs, which is a great event. According to the dispatching principle, in the face of the severe flood control situation of Xin 'anjiang Reservoir, the expert group of the Provincial Water Resources Department and the field expert group dynamically analyzed the opening and closing schemes of 17 1, compared the hourly water level change process of each scheme and the water level change trend of the downstream main reaches, studied and put forward 57 dispatching schemes, and put forward optimization suggestions to ensure the flood discharge safety, order and stability of Xin 'anjiang Reservoir to the maximum extent.

In the formulation of these dispatching schemes, the most critical factor depends on the rainfall in the reservoir area. Xin 'anjiang River Basin is located in the core area affected by heavy precipitation cloud system in Meiyu belt. The cumulative area rainfall 1047 mm in the basin above the dam site of Xin 'anjiang Reservoir is 3.2 times of the annual meiyu (328 mm). Therefore, heavy rainfall and rapid rise of water level are decisive factors in decision-making.

Zhejiang News-Authoritative Interpretation of the Ministry of Water Resources after Flood Restoration: N "Why" about the flood discharge of Xin 'anjiang Reservoir