Rain prompts alerts, evacuations near Wanli barrier lake in Taiwan

Precautionary evacuations are underway for approximately 200 residents from seven villages in Hualien County as a newly formed barrier lake in the Wanli River swells towards its capacity.

The Forestry and Nature Conservation Agency's (FANCA) Hualien Branch issued a yellow alert yesterday morning, warning that the barrier lake could overflow within 48 hours due to continuous rainfall. The alert was upgraded at noon, with authorities now estimating a potential overflow within 24 hours.

About 70 households across Wanrong and Fenglin townships have been evacuated and are temporarily housed in public buildings. Access to the affected areas has been restricted with the closure of three bridges.

These measures are being taken as rainfall is expected to reach 58mm within the next 24 to 48 hours. Reconnaissance flights of the lake have been hampered by heavy cloud cover, but it is estimated to be between 40 and 60 percent full. The Wanli River barrier lake is located about 7km north of where a similar barrier lake on the Mataian River burst in September last year, causing 19 deaths and flooding over 1,600 homes.

Officials estimate the Wanli River barrier lake's capacity at 6 million cubic meters, with an overflow potentially eroding the natural dam. Even 1.5 million cubic meters of water could cause significant downstream impact, highlighting the urgency of the situation.