Water level meter installed at Hualien barrier lake to improve monitoring

Taipei, June 28 (CNA) A water level meter was installed Sunday at the barrier lake on the Wanli River in Hualien County, allowing authorities to receive water-level data every 10 minutes to improve monitoring and emergency response, the Forestry and Nature Conservation Agency's (FANCA) Hualien Branch said.

With assistance from the National Airborne Service Corps (NASC), a disaster prevention team from National Cheng Kung University (NCKU) installed the device at around 9 a.m., the agency said.

The data is now transmitted to the Ministry of Agriculture's State-owned Forest Disaster Prevention Response and Barrier Lake Monitoring System, FANCA said.

Meanwhile, the risk of the barrier lake bursting has been downgraded from a red to a yellow alert, while authorities warned that the landslide-dammed lake still poses a risk of breaching within 10 days.

The Hualien County government urged the public to stay away from the Wanli River, Matai'an Creek and surrounding hazardous areas.

As of 9 a.m. Sunday, 186 residents had been evacuated from Wanrong and Fenglin townships, including 99 from Wanrong and 87 from Fenglin.

Hualien County Magistrate Hsu Chen-wei (徐榛蔚) said police patrols and fire department drones were monitoring the riverbed to prevent people from entering hazardous areas.

According to the monitoring system, the lake's water level stood at 1,067 meters as of 6:30 p.m., with an estimated storage volume of 2.4 million cubic meters. The overflow elevation is estimated at about 1,080 meters.

FANCA said the lake lies in a deep valley in the Central Mountain Range, where monitoring had previously relied on aerial surveys and drone observations. Those methods depend heavily on weather conditions and cannot provide continuous real-time data.

After the barrier lake was discovered on June 21, the Hualien branch commissioned an NCKU team to prepare the monitoring device. Installation, originally scheduled for Saturday, was postponed because of poor weather and completed Sunday.

The agency said the meter was donated by the Japan-Taiwan Exchange Association in 2025 and was previously used to monitor the barrier lake on Matai'an Creek. After completing that mission, the device was refurbished by the NCKU team before being redeployed to the Wanli River.

According to FANCA, the lake is about 56 percent full and, with rainfall easing, the risk of an imminent overflow is relatively low.

However, suspected seepage within the natural dam could still trigger a "piping" effect, in which water erodes material from inside the dam and weakens it, prompting authorities to continue prohibiting entry into the river channel, the agency said.

Matai'an Creek barrier lake

Separately, the Hualien branch said all 11 construction workers carrying out disaster prevention work at the Matai'an Creek barrier lake were airlifted to safety Sunday morning.

The workers had been conducting emergency stabilization work before the flood season, but heavy rainfall in Hualien's mountainous areas since June triggered landslides and mudslides that cut off access to the riverbed and significantly increased construction risks, the agency said.

The Hualien branch said it requested assistance from the NASC to evacuate the workers by helicopter and thanked both the construction team and the corps for ensuring the operation was completed safely.

The Matai'an Creek barrier lake, located about 7 kilometers south of the Wanli River barrier lake, breached in September 2025, causing 19 deaths and flooding more than 1,600 homes.