Last week, the Chinese government said that nearly 400 dams in the quake-affected region had suffered some level of damage, but there have been no reports of failures.Some experts are still concerned about the dams’ safety.

There are five dams along the Min River that pass through the epicenter of the earthquake, reports the WSJ. All are upstream from the Zipingpu dam and reservoir, which can hold more than 35 billion cubic feet of water.

Fan Xiao, a Chengdu-based geologist, said officials don’t yet have a complete grasp of the danger from the dams upstream, some of which haven’t been assessed because roads remain impassable, the WSJ reports.

“Right now, it’s really hard to estimate the danger or the amount of water that could be released if one or more of these dams fail,” Mr. Fan said. In some cases, flood gates are jammed, causing reservoir levels to rise to dangerous levels that could breach the dams, he said.

Also of concern is the high risk of aftershocks, reports the WSJ. The region has already suffered from 155 aftershocks of at least magnitude 4.0. Thousands across the region fled to the streets following a statement from the Chinese National Seismology Bureau warning of a “rather great” chance of a much larger aftershock of magnitude 6 to 7.

Directly in the path of the Min River dams is the town of Dujiangyan, home to 600,000 people and one of the places hardest hit by the earthquake. Chengdu, a city of about 10 million people could also be affected by a collapse at Zipingpu.

http://online.wsj.com/