TAIPEI (Taiwan News) — The Forestry and Nature Conservation Administration has discovered a newly formed barrier lake in the upper reaches of the Wanli River in Hualien County’s mountains and is closely monitoring the site for potential downstream impacts.
The lake is located about 7 km north of the Mataian Creek barrier lake, which flooded parts of Guangfu Township last year. Officials said the newly discovered barrier lake is about 30 km upstream from the Wanli River Bridge on Provincial Highway 9, per CNA.
An aerial survey conducted Monday found a landslide area covering roughly 45 hectares. The lake has not yet reached capacity or begun overflowing, and no significant seepage or structural damage to the landslide dam was observed. However, sporadic rockfalls continue in the area, prompting ongoing monitoring efforts.
According to preliminary aerial assessments, the barrier lake could hold up to 6 million cubic meters of water. Officials cautioned that if water levels continue to rise and eventually overtop the dam, downstream areas, including Wanrong and Fenglin townships, as well as several highway and railway bridges, could be affected.
Forestry and Nature Conservation Administration Hualien Branch Director Huang Chun-tse (黃群策) said the newly discovered barrier lake is in an even more remote location than the Mataian Creek barrier lake. The river valley is characterized by steep canyon walls, a winding river channel, a sharp longitudinal slope, and a riverbed filled with large boulders.
The challenging terrain has complicated efforts to conduct on-site inspections. Multiple landslides along Wanrong Forest Road have blocked access, preventing personnel and equipment from reaching the site in the short term.
Officials said helicopters are also unable to lower investigators into the area or install monitoring equipment because of the rugged landscape, per CNA.
Huang said officials are developing plans for additional surveys while seeking support from relevant agencies for further aerial reconnaissance. The aerial data will be used to assess the dam’s structure, water storage capacity, and potential risks.
The administration has notified relevant agencies to closely monitor downstream river gauges and water levels. Officials emphasized that current estimates are based on preliminary visual observations from the air and that a more comprehensive risk assessment will be conducted once additional data is analyzed.
