I note from comments below that now that the landslide dam at Tangjiashan has failed the disaster is considered to be over. Please let's be a little careful here. It is true that the flood waves has now passed through the upper parts of the river. Below is the graph of the reported discharges as per the comments left on earlier postings:
The water level is clearly dropping. However, the key issue is what happens downstream - it will take some time for the flood wave to reach these downstream areas. A wave of this size will inevitably cause considerable damage along the channel. We will know that the disaster has been averted when the flood wave disperses on the plains. Until we know this has occurred we must be careful. However, the Chinese government has been effective in moving people to date, so all the indications are that they are managing this crisis well.
Note that there is also a secondary risk that this wave will trigger further landslides.