In response to the forecast that the Vu Gia - Thu Bon River Basin will have heavy, long-term rain on a large scale from 250-500 mm/time, with some places over 700 mm/time, Song Tranh Hydropower Company immediately issued a notice on operating and regulating the overflow of the reservoir to gradually lower the reservoir to catch floods and switch to the operating mode of cutting and reducing floods downstream.
According to the flood warning bulletin of the Central Region Hydrometeorological Station issued at 3:30 p.m. on November 10, 2023, from November 13 to November 17, in the Vu Gia - Thu Bon River Basin, there will be moderate rain, heavy rain, some places have very heavy rain and thunderstorms with a common rainfall of 250-500 mm/time, some places over 700 mm/time, warning of level 1 natural disaster risk due to heavy rain. Implementing the order Operation of the reservoir by the Steering Committee for Disaster Prevention and Control of Quang Nam province, Song Tranh Hydropower Company immediately issued a notice to operate and regulate the overflow of the reservoir to gradually lower the lake water level to +167m elevation and switch to cutting operation mod, reducing floods downstream according to regulations to send to local authorities from central to local levels, and lake owners on the same ladder.
Accordingly, the starting time of overflow regulation operation is 2:30 p.m. on November 11, 2023, the total flow of regulation operation is expected to be from 200 ÷ 900 m3/s (depending on water flow to the lake). At 02:30 on November 14, 2023, the lake water level was lowered to +167m in accordance with the direction of the Steering Committee for Disaster Prevention and Control of Quang Nam Province to be ready to cut and reduce floods downstream according to the provisions of Process 1865 with capacity to cut and reduce floods of nearly 160 million m3.
At 04:00 on November 14, 2023, floods began to appear on the lake (Parameters at 04:00: MNH = 167.0m, Qd = 731.6 m3/s, Qd = 215 m3/s, Qoverflow = 515.8 m3 /S).
Rainfall measured on November 14, 2023
Based on the short-term forecast bulletin for flood control and operation of the Song Tranh 2 Hydropower reservoir of the Quang Nam Provincial Hydrometeorological Station broadcast at 04:30 on November 14, 2023, forecast: there will be rain in the Song Tranh basin. heavy, to very heavy rain and the flow to Song Tranh 2 hydroelectric reservoir continued to increase rapidly, the Company immediately issued a notice to adjust the discharge flow through the overflow to continue to maintain the reservoir water level +167m and convert Operational level of flood reduction and reduction for downstream areas according to the provisions of Process 1865 to be sent to local authorities from central to local levels, and lake owners on the same ladder.
By 9:00 a.m. on November 14, 2023, the water flowing to the lake increased to 1936 m3/s, implementing the regulations of the the Inter-reservoir Process 1865, the Company began gradually raising the lake water level to reduce floods downstream. At 12:30 on November 14, 2023, the flood to the lake peaked with a flow of 3,336.3 m3/s. The Company operated to reduce floods by over 50% of the flood peak flow, only regulating the flow downstream was 1291.58 m3/s.
Flood chart number 3 in 2023 - Song Tranh 2 Hydropower Plant
On November 15, 2023, implementing the lake operation order of the Steering Committee for Disaster Prevention and Control of Quang Nam Province, the Company immediately issued an operation notice to ensure that the water level of Song Tranh 2 lake is not greater than the flood level of 173m. and transfer the operating mode according to regulations to send to local authorities from central to local levels, and lake owners on the same ladder.
On November 17, 2023, implementing the lake operation order of the Steering Committee for Disaster Prevention and Control of Quang Nam Province, the Company immediately issued an operation notice to ensure that the water level of Song Tranh 2 lake is not greater than the water level elevation of 174.8m. and transfer the operating mode according to regulations to send to local authorities from central to local levels, and lake owners on the same ladder. By 10:30 p.m. on November 17, 2023, the water flow to the lake gradually decreased and this rainy period ended with a total amount of flood water reaching the lake of 398.8 million m3, the total amount of flood reduction water for the downstream area was 150.6 million m3. , during the operation process, the Company has closely coordinated with local authorities at all levels in information work, reporting on the operating situation, especially strictly complying with the lake operation order issued by the Provincial Steering Committee for Natural Disaster Prevention and Control. Quang Nam highly appreciated.
Song Tranh 2 Hydropower Reservoir is effectively regulating and reducing floods downstream
Currently, the Company is continuing to operate and regulate the reservoir to gradually raise the reservoir water level to near the normal water level rise of 175m according to the Inter-reservoir Process 1865. Equipment systems and works of Song Hydropower Plant Painting 2 is operating stably, safely and reliably according to design./.