New Hualien barrier lake at risk of overflow, may require evacuation

Taipei, June 23 (CNA) Fears that a newly formed barrier lake upstream of Wanli River in Hualien County could begin overflowing in 10 to 20 days has led authorities to identify households in at-risk areas and urge residents to evacuate before the designated deadline.

The barrier lake was discovered Sunday by the Forestry and Nature Conservation Agency's (FANCA) Hualien Branch. Aerial surveys found that the area of the landslide that created the barrier lake covered about 45 hectares, with rockfalls continuing there.

In a radio interview Tuesday, Minister Without Portfolio Chi Lien-cheng (季連成) said the barrier lake is located about 20 kilometers upstream from Wanrong Township at an elevation of roughly 1,000 meters.

Its estimated capacity is 6 million cubic meters of water, and an overflow could erode the natural dam and trigger a breach, with as little as 1.5 million cubic meters of water capable of causing a significant downstream impact, Chi said.

If such a breach were to occur, Mingli Village in Wanrong Township would be the first area affected, he said.

The newly formed lake is roughly 7 kilometers north of where the Matai'an barrier lake burst in September 2025. The breach left 19 people dead and flooded over 1,600 homes in Guangfu Township, which is just to the south of Wanrong Township.

Chi said FANCA's Hualien Branch has established a response task force and commissioned a team from National Yang Ming Chiao Tung University to assess the situation, and he will travel to Hualien next week to provide guidance on disaster preparedness efforts.

At present, a two-stage evacuation strategy has been planned, Chi said.

The current phase involves precautionary evacuations, while a second emergency evacuation would be carried out if the barrier lake begins to overflow or shows signs of failure.