According to Hoa Binh Hydropower Company, at 9:00 a.m. on September 22, the water level of Hoa Binh Lake was at 116.99 m, the water flow into the lake was 3,179 m3/s, the water flow discharged downstream was 2,032 m3/s, the water level of the lake continued to increase.
Pursuant to telegram No. 7101 of the Ministry of Agriculture and Rural Development, Hoa Binh Hydropower Company announced the opening of bottom spillway No. 1 at 12:00 noon on the same day with a discharge flow downstream of 3,900m3/s.
Then, at 11:00 a.m. the same day, the upstream water level of Hoa Binh Lake was at 117.05 m, the flow to the lake was 3,813 m3/s, and the flow discharged downstream was 3,900 m3/s.
Pursuant to telegram No. 7103, Hoa Binh Hydropower Company announced the opening of bottom spillway No. 2 at 1:00 p.m. the same day. The total water flow discharged downstream, including through the spillway and the power generation flow through the generator, is about 5,480 m3/s.
Then, at 1 p.m., the water flow to Hoa Binh Lake suddenly increased to 7,030 m3/s, while the discharge was only over 5,000 m3/s, the lake water level was 0.15 m higher than the normal water level. The Ministry of Agriculture and Rural Development continued to request the opening of the third bottom discharge gate of the hydropower plant at 3 p.m.
It is known that on the same day, the Ministry of Agriculture and Rural Development also sent a document to the People's Committees of the following provinces and cities: Hoa Binh, Phu Tho, Vinh Phuc, Hanoi, Bac Ninh, Hai Duong, Hai Phong, Hung Yen, Ha Nam, Thai Binh, Nam Dinh, Ninh Binh regarding ensuring downstream safety when operating the Hoa Binh hydropower reservoir.
