TAIPEI (Taiwan News) — The water level at the Swallow Grotto (Yanzikou) barrier lake in Hualien stood 2.94 meters below the top of the dam on Tuesday, as authorities accelerated excavation to create a safe work area and reduce pressure after days of heavy rain.

Huang Chun-tse (黃群策), head of the Forestry and Nature Conservation Agency’s Hualien Office, said rainfall upstream on the Liwu River reached 39 millimeters Monday night, per CNA. Between 9 p.m. and midnight, the water level briefly rose to within 2 meters of the crest before receding to its current level.

Authorities are working to speed overflow discharge from the barrier lake to lower the overall water level. Even if downstream levels rise, the impact on nearby communities and infrastructure should remain limited.

Huang said residents have been advised to evacuate as a precaution, and officials remain on high alert in case of further heavy rain.

Excavators are being used to lower the height of the barrier lake. The original plan was to reduce it by 5 meters, but engineers now aim to cut it by 10 meters to keep it below the nearby highway and reduce pressure on the dam.

However, Huang said the first step is to build a work platform, as falling rocks continue to pose a serious safety risk. The project will proceed in stages, and the completion date has yet to be determined.

On Oct. 17, a landslide occurred in the Swallow Grotto gorge section of Provincial Highway 8 within Taroko National Park, blocking the Liwu River and forming the barrier lake. Water flows into the lake through the western entrance of the Jinheng Tunnel and exits through the eastern side, spilling over Ludan Bridge into Ludan Creek before rejoining the Liwu River.

A red alert remains in effect, with the eastern section of the highway closed and Taroko National Park temporarily closed to visitors.