Continued Seismic Activity After Budhigandaki Blockage: How Significant Is the Flood Risk?
Image source: Centre of Hydrology and Water Resources Research
Officials from the Centre of Hydrology and Water Resources Research reported tremors in the ground surrounding the Budhigandaki River in Chumnubri, Gorkha, when a landslide blocked the river’s flow.
According to Rajan Bhattarai, the centre’s Deputy Executive Director and spokesperson, seismic vibrations were recorded in the area on Sunday morning.
“Around 4:30 a.m., a signal measuring approximately 4.2 on the Richter scale was detected. Observations suggest that a landslide occurred roughly at that time,” he said. “Although it initially seemed like minor tremors, we have not emphasized them significantly.”
He noted that further investigation is required to confirm the exact cause of this event.
About one and a half months ago, during flooding in the Bhote Koshi-Trishuli region, seismic activity was also detected in the Langtang Lirung area. Initially, it was suspected that the earthquakes caused landslides, but later scientific analysis confirmed that the tremors were caused by landslides.
A situation report issued by the centre on Saturday night shows that a landslide had occurred near Tumje in Chumnubri, a tributary area of Budhigandaki in Gorkha.
“Preliminary information and satellite image observations indicate that the landslide blocked the river’s flow, causing water to accumulate and leading to sudden releases as the blockage weakened or collapsed,” the report stated, calling for further studies.
The National Disaster Risk Reduction and Management Authority confirmed that the landslide from Siringe Himal, located between Lokpa of Chumnubri-6 and Chumdeling, has blocked the local Uingulung Khola stream.
Several media outlets have also reported the occurrence of an avalanche in Chumnubri.
“We have only confirmed a landslide and the satellite images analyzed clearly show a landslide,” said spokesperson Bhattarai. “Due to extensive cloud cover in satellite images, it is unclear whether some parts of the glacier above also fell.”
Rescue Operation Underway
Image source: Nepal Army
Officials have confirmed that search and rescue efforts continued on Monday in the affected area.
Ram KC, head of the Disaster Response Branch at the authority, explained that people stranded by flood-blocked routes are being evacuated to safer locations.
According to KC, the flood has impacted three local administrative areas in Gorkha: Chumnubri, Dharche, and Arughat. Although road access was cut off in certain places due to collapsed bridges, eight truckloads of relief supplies were delivered to Arughat by Sunday evening.
“Approximately 300 people in Gorkha and Dhading have been affected and the first phase of relief has already reached them.”
“In remote areas where road networks are disconnected, relief materials are being delivered by Nepal Army helicopters as of Monday,” KC added.
He highlighted travel difficulties in Arughat and Chumnubri due to the collapse of permanent bridges.
Preparations are underway to install a 22-meter-long Bailey bridge in Arughat to temporarily restore traffic, with work expected to begin shortly.
Seven people, including two women and five men from Chumnubri, remain unaccounted for due to the flooding. On Sunday, the Nepal Army evacuated 95 individuals, including nine foreign nationals, from the affected region.
Continuous Monitoring
Image source: NDRRMA
Deputy Executive Director and spokesperson Bhattarai of the Centre of Hydrology and Water Resources Research noted that the landslide area on Sunday was identified as a zone with high seismic risk.
“The loose soil made the area susceptible to landslides,” he explained.
Some analysts suggest that the soil in the mountainous and hilly regions has weakened since the 2015 earthquake, raising fears that similar events may recur.
The epicenter of that earthquake was near Barpak, Gorkha.
Regarding the ongoing risk, Bhattarai stated, “It cannot be ruled out. The area was already at risk. However, in this particular incident, the danger appears to have decreased.”
KC from the disaster authority also noted that the risk is lower on Monday compared to Sunday.
“On Sunday, the river was blocked causing water to accumulate. On Monday, that condition is not present,” he said.
“Yet, we continue to monitor the situation closely.”
Our news is also available on YouTube. To subscribe to our channel and watch published videos, click here. You can also find our content on Facebook, Instagram, and Twitter. Additionally, the BBC Nepali Service program airs on radio from Monday to Friday at 8:45 PM.