Why does heavy rain not significantly change the water level of Hoa Binh Hydroelectric Lake?

In recent days, despite heavy rain, the water level at Hoa Binh Hydropower Reservoir has shown little change.

According to observations from our reporter, the northwestern provinces in general, and Hoa Binh province in particular, have experienced moderate to heavy rainfall recently.

In an interview, representatives from several hydropower plants stated: “The heavy rains over the past few days are good news for hydropower reservoirs, especially for Son La and Hoa Binh reservoirs, after a dry spell that brought water levels close to dead storage.”

On the morning of June 27, our reporter visited Bich Ha Port (Hoa Binh commune, Hoa Binh city) and the area surrounding the Hoa Binh Hydropower Reservoir to assess the water level following the recent heavy rains.

Heavy rainfall has caused the inflow to the Hoa Binh Hydropower Reservoir to reach hundreds to thousands of cubic meters per second; however, since the Hoa Binh Hydropower Plant continues to operate all 8 turbines, the water level in the reservoir has not changed significantly. (Photo: Tue Linh).

Despite the heavy rains, our reporter observed that the water level in the Hoa Binh Hydropower Reservoir has remained relatively stable.

In discussions with our reporter, Ms. Luu, an employee at a fish farming facility on the Hoa Binh Hydropower Reservoir, stated: “In the past 2-3 days, although there has been heavy to very heavy rain, the water level in the reservoir has not changed much. Currently, the water level does not significantly affect our fish farming operations or those of the surrounding households.”

According to the management of Hoa Binh Hydropower Plant, the heavy rains in recent days have stabilized the inflow to the Hoa Binh Hydropower Reservoir compared to before. During the periods of heavy rain, the inflow to the reservoir can reach up to 1,000 m³/s. However, since the morning of June 26, the rain has decreased, leading to a reduction in inflow.

Additionally, representatives from the Hoa Binh Hydropower Plant mentioned that if heavy rains continue and the inflow maintains at 1,000 m³/s for about 7-8 days, the hydropower plant will be able to operate at full capacity.

The water level in the Hoa Binh Hydropower Reservoir does not affect fish farming for local households. (Photo: Tue Linh).

Explaining why, despite the heavy rains and inflow reaching hundreds to thousands of cubic meters per second, the water level in the Hoa Binh Hydropower Plant has not changed significantly, the management added: “Even though the inflow is substantial, the plant has had to operate all 8 turbines and maintain water supply for the downstream areas, which has kept the water level stable compared to previous conditions.”

Previously, on June 11, the management of the Hoa Binh Hydropower Plant reported: “The inflow to the reservoir was very low, at only about 40 m³/s; the water surface level was approximately 103m, just 23m above the dead storage level. If we maximize extraction, after about 3 days, we would not have enough pressure to generate maximum capacity, impacting our reserve capacity, and in about 12-13 days, the water level would reach the dead storage.”

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