No immediate threat from Swallow Grotto barrier lake, red alert lifted

Taipei, Oct. 23 (CNA) The red alert for downstream areas of the Swallow Grotto (Yanzikou) barrier lake in Hualien County's Taroko National Park has been lifted after the Ministry of Agriculture assessed that the lake is unlikely to pose a threat to local residents in the near future.

The Hualien Branch of the Forestry and Nature Conservation Agency lifted the alert at 1:30 p.m. on Thursday, saying the lake's water level had stabilized. It added that the decision also took into account rainfall forecasts and other indicators, which suggest the potential overflow situation has not worsened.

Oct. 19: Taroko barrier lake stable, unlikely to trigger major debris flow: FANCA

According to monitoring by the Hualien Branch earlier in the day, the lake's water level remained 3.31 meters below the overflow point. The lake, which covers an area of about 11 hectares, holds 1.91 million tons of water and could store an additional 390,000 tons.

The decision was based on data and simulations provided by experts from National Cheng Kung University, which indicated that the risk remains low over the next 48 hours even in the event of runoff combined with extreme dam-break flow, the agency said.

The branch attributed the dam's low permeability and structural stability to its make up of marble blocks and disintegrated soil and sand, adding that aerial photographs taken over the past few days showed no significant changes.

However, the road between the flooded area at the west entrance of Jin Heng Tunnel and Ludan Bridge remained closed, as water overflow from the dam continued.

The lifting of the red alert means residents in downstream areas who had been evacuated can now return home. It also led to the disbanding of the Central Emergency Operation Center, which had been active since Sept. 21.

The 33-day duration was the longest the center has operated in 25 years, Hsiao Huan-chang (蕭煥章), head of the National Fire Agency, said in a press release.