Interesting read from Aug 2014.
It appears that whoever is in control, the dam may self destruct for lack a maintenance.
That given, Not sure ISIS/ISIL/IS (who ever) has the wherewithal to hasten the event?
But, If they stopped the turbines and flow gates, backed up a couple bazillion gallons of winter run-off, It surely looks feasible..
http://www.businessinsider.com/mosul...unsound-2014-8