I don't think the dam can be "fixed".  If it were to hold long enough, perhaps they could biuld upstream in an effort to create more capacity and reduce the toatal load on the existing structure.

Regardless, there are future years to consider - I don't believe that climate is "changing" but it IS quite variable and the rainfall they are experiencing may be one of a few successive events that would make up an "extreme" that doesn't do much to long term averages.  I personally have no doubt that an uptick in seismic activity is related to the "new" load on the local 'crust'.  Only time will tell if it is going to increase or subside.