On the evening of October 4th, leaders of Tri An Hydropower Company (Tri An Ward, Dong Nai City) confirmed that the unit continued to increase the discharge rate through the spillway to regulate the reservoir. According to company leaders, the current high tide is low, while a large amount of water is flowing into the reservoir from upstream, so an increase in discharge is necessary. This is a normal reservoir regulation activity as in previous years.
According to hydrological data at 8:00 AM on October 4th, the upstream water level of Tri An Reservoir reached 61.666m, while the downstream water level at the power plant was 6.4m. The inflow into the reservoir reached 1,900 m³/s. The total outflow to the downstream area at this time was 1,697 m³/s, including 915 m³/s through the spillway and 782 m³/s through the power generation turbines.
Given the high water inflow into the reservoir and the low water level downstream, from 13:00 on the same day, the company opened the 7th spillway gate, increasing the flow rate through the dam to 1,067 m³/s. By 15:00, the 8th spillway gate was opened, further increasing the discharge rate to 1,220 m³/s. Water poured over the spillway, creating a strong flow downstream into the Dong Nai River.
Along with the flow rate through the power generation turbines ranging from 460–800 m³/s, the total downstream water flow is expected to fluctuate between 1,680–2,020 m³/s, depending on the National Dispatching method. Thus, at its peak, the downstream water flow could exceed 2 million liters per second. This is the total flow rate through the spillway and power generation turbines.
Previously, due to the rising water level downstream of the Dong Nai River, the Tri An Hydropower Plant gradually closed some of its spillway gates. By September 28th, only one gate remained operational with a flow rate of 146 m³/s. When the downstream water level dropped, from October 1st to 3rd, the plant opened five more gates, bringing the total number of operational gates to six, with a discharge flow rate of 915 m³/s. On October 4th, the remaining two gates were opened, bringing all eight spillway gates into operation.
The Tri An Hydropower Company stated that it will flexibly regulate the amount of water flowing through the spillway depending on weather conditions, inflow into the reservoir, reservoir water level, and downstream water level at the Bien Hoa hydrological station. This regulation aims to ensure the safety of the dam and downstream areas. The company requested that relevant local authorities inform residents in downstream areas so they can proactively take preventive measures to minimize potential impacts.
Source: https://baophapluat.vn/mo-8-cua-xa-thuy-dien-tri-an-nguoi-dan-ha-du-can-chu-dong-phong-ngua-anh-huong.html
