Tangjiashan Lake Lake

Tangjiashan Lake is a landslide-dammed lake in Sichuan province, China, formed after the 12 May 2008 Wenchuan earthquake when slope failures on Tangjiashan Mountain blocked a river valley. The sudden impoundment attracted major emergency response because of the volume of water behind the natural dam and the danger of catastrophic downstream flooding.

The blocked valley held large quantities of water in the weeks after the earthquake, prompting large-scale engineering works to create spillways and tunnels to release the water safely. Those emergency works in June 2008 prevented an uncontrolled breach that would have threatened towns and infrastructure downstream.

The lake sits in mountainous terrain near Beichuan County in northern Sichuan, within the earthquake-affected region northwest of the provincial capital Chengdu.

• Origin: Formed suddenly after the 12 May 2008 Wenchuan (Sichuan) earthquake when a landslide dammed a mountain river, creating an impounded lake that posed a major downstream flood risk.
• Emergency drainage: Emergency engineering works in June 2008 - including controlled blasting and construction of drainage channels and tunnels - were used to lower water levels and reduce the risk to downstream communities.

Tangjiashan Lake is in Mianyang/Beichuan area of Sichuan. Access is by road from Chengdu (several hours’ drive) or from Mianyang; check local travel advisories and routes, as roads can be affected by past seismic events.

• If planning to visit the Tangjiashan dammed lake area, check local safety advisories-some parts remain restricted or monitored due to landslide risk.
• Visit the nearby town of Beichuan for context on the 2008 earthquake and the emergency response that followed.
• Bring a map and a local guide; roads were heavily affected by the 2008 disaster and conditions can vary.