Hualien landslide dam downgraded to yellow alert, but overflow risk remains

The alert level for the Wanli River landslide dam in Hualien has been lowered from red to yellow, officials announced Sunday afternoon. This adjustment comes as the inflow rate into the lake has decreased and rainfall has eased, according to the Hualien Forest District Office of the Agriculture Ministry's Forestry and Nature Conservation Agency.

Despite the downgraded alert, the office stressed that the risk remains significant. Afternoon thunderstorms are unpredictable, and the public should not relax their guard. Local governments and downstream agencies must continue with preventative evacuations and clear river channels to mitigate potential disaster from overflow.

The lake's water level is currently at 1081 meters, just about 5 meters below the predicted overflow elevation of 1086 meters. The total storage volume has reached 4.25 million tons, approximately 83% of its maximum capacity. While current estimates suggest the lake could overflow around July 15, a significant rainfall event could cause an earlier overflow. The office is continuously monitoring water levels and rainfall.

Officials are working with expert teams from universities to monitor the dam's stability using water level gauges, seismic instruments, and drone aerial surveys. The landslide dam, formed by accumulated debris from past collapses, is inherently unstable and susceptible to risks from rainfall, inflow rates, and terrain. The current alert zone includes eight villages in Wanrong Township and Fenglin Township, impacting infrastructure like the Taiwan Railways Administration lines and major bridges.