Taiwan Faces Flood Risk as Landslide Lake Threatens Collapse

Authorities initiate evacuations and establish emergency response centers due to potential breach of a landslide-induced lake in Nantou County.

Heavy rainfall and the impact of Typhoon Doksuri have led to the formation of a landslide-induced lake along the Qingshui River in Caoling, Nantou County, Taiwan. The Fourth River Management Office of the Water Resources Agency has assessed the risk of a breach and issued a warning, advising local authorities to prepare for emergency response.

In response to the potential danger, the town of Zhushan has activated its Level 1 emergency response center. Mayor Chen Dong-mu has directed the precautionary evacuation of residents from low-lying areas along the Qingshui River, including eight villages: Tongtou, Ruizhu, Pingding, Liyu, Fuxing, Dexing, Zhonghe, and Zhongqi. The town hall began the evacuation process in the late afternoon, ensuring the mobilization of personnel and the preparation of shelters.

As of now, 45 households, totaling 76 individuals, have been evacuated and have chosen to stay with relatives. Mayor Chen emphasized the paramount importance of safety, urging residents to stay away from the riverbanks and high-risk areas to prevent any loss of life. The Zhushan town hall is maintaining close communication with the Water Resources Agency and other relevant units to monitor the situation of the landslide lake and safeguard the lives and property of the community.

A team comprising engineers from the Water Resources Planning Institute and the Fourth River Management Office conducted an on-site investigation. Preliminary estimates indicate the landslide dam is approximately 60 meters high and 320 meters long, with a volume of about 2.15 million cubic meters. The lake's storage capacity is estimated at 22.45 million cubic meters, covering an area of approximately 62 hectares. In the event of a breach within one hour, the estimated average flow rate is around 6,200 cubic meters per second, which is comparable to the 20-year return period flow for the Qingshui River's management plan.

The Fourth River Management Office stated that while the estimated breach flow does not exceed the Qingshui River's warning level, the inherent uncertainties associated with landslide dams necessitate heightened vigilance. Authorities are strengthening riverbank engineering downstream and implementing access controls for the public. Residents are strongly advised to avoid the riverbanks downstream of the Qingshui River for their safety.