Nanhua Reservoir overflows for second time this year due to heavy rain

Southern Taiwan's Nanhua Reservoir has overflowed for the second time this year, reaching its full capacity of 180 meters following heavy rainfall in its catchment area. The reservoir, a key water source for Tainan and Kaohsiung, had been near capacity and was already transferring approximately 330,000 cubic meters of water daily to the Wushantou Reservoir via the Zengwen-Nanhua inter-basin water transfer tunnel. This transfer aimed to store water for the second rice crop irrigation and optimize regional water resource allocation.

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The reservoir reached its full water level again today, overflowing naturally for the second time this year. Residents downstream are urged to be careful.

As of 4 p.m. on the day of the report, the catchment area had received over 35 millimeters of rain, causing continuous inflow that exceeded the reservoir's capacity. The current overflow rate is a modest 11 cubic meters per second. However, water authorities are prepared to open the sediment-discharging tunnel if significant rainfall persists and the overflow rate increases. This would allow for both water release and sediment flushing.

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The catchment area has received over 35 millimeters of rain, with continuous inflow exceeding the full water level.

Despite the current low overflow volume, the influence of a low-pressure system and southwest monsoon continues, presenting opportunities for further substantial rainfall in the catchment. Water company officials are urging residents living downstream of the Houqu River to stay away from the riverbanks and ensure their safety.

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Although the current overflow rate is not large, the low-pressure system and southwest monsoon mean there's still a chance of heavy rain. We urge downstream residents to stay away from the riverbanks and ensure their safety.