A barrier lake along Hualien County’s Wanli River overflowed early today with impact expected to remain limited. The Forestry and Nature Conservation Agency confirmed the overflow through drone footage taken at dawn. Consequently, officials reported stable conditions with no significant erosion affecting the natural dam structure.
Indeed, the agency’s Hualien branch noted the outflow remained steady without cutting into the barrier lake’s structure. Officials confirmed the lake reached its dam crest elevation of 1,090.5 meters around 1:40 a.m. Afterward, water levels fluctuated, indicating the overflow process had officially begun overnight. The highest recorded level before overflow reached 1,090.68 meters, with an estimated 6.02 million cubic meters total.
Furthermore, drone images revealed no obvious erosion at the overflow point, easing immediate safety concerns considerably. Since the natural dam contains substantial rocks and coarse gravel, officials said current flow remains insufficient for major erosion. Therefore, under sunny or light-rain conditions, the barrier lake should erode gradually within the river channel. Additionally, weather forecasts predicted only limited precipitation upstream, estimating roughly 21.7 millimeters over the next day.
Given these favorable conditions, the Directorate-General of Highways reopened the Wanli River Bridge section ahead of schedule. Meanwhile, Taiwan Railway Corp confirmed trains continued operating normally through the affected bridge area. Nevertheless, the company stated it would maintain heightened monitoring and alert status moving forward.
Notably, authorities first discovered this barrier lake upstream on June 21 this year. Officials had previously issued a red flood alert warning downstream residents about potential overflow risks. Although initially forecast for last Friday, the overflow was delayed until Monday due to increased seepage. This seepage primarily involved surface erosion, with the natural dam remaining structurally stable throughout.
Ultimately, this barrier lake overflow demonstrates successful monitoring and preparation by Taiwan’s disaster response agencies. Going forward, officials will continue tracking conditions to ensure downstream communities remain protected from further risks.
