Most of the lakes and damaged dams in Sichuan are currently safe but face the danger of heavy rain and aftershocks in the next few days.
Li Chengyun, vice-governor of Sichuan province, said at a press briefing on Monday that 21 lakes could breach their banks, and efforts are being made to reduce the risks.
The National Meteorological Bureau has forecast moderate or heavy rain - 13 to 30 mm - to hit the disaster areas in the next three days.
The Sichuan earthquake administration said there is still the possibility of severe aftershocks.
Xu Shuisen, an official with the Chengdu earthquake administration, told China Business News the government was aware of the danger of floods caused by lakes bursting their banks, and had taken steps to reduce the risks.
Two experts and soldiers have been assigned to each lake and dam to keep a 24-hour watch.
The government also has plans in hand to evacuate people downstream should the need arise. In some places, troops and construction teams have been deployed to divert the flow of water from the lakes and dams.
One lake that poses a threat is in Beichuan county. The lake was formed due a landslide that partially blocked the Qianjiang River. It is 40 m deep and contains about 30-40 million cu m of water.
In Qingchuan county, another lake has been formed containing about 10 million cu m of water. Experts with the Sichuan water resources department said the lake's water level was rising. All people living downstream have been evacuated.