Some time ago I heard a comment on some National Geographic or Discovery Channel program that the earth rotation is slowed down due to water trapped in dams I did not pay attention to this at the time as it was said to be a fraction of a second.

Planning my next vacation I came across this article and this made me wonder about the effects of a major dam failing at full capacity this dam has $180km^3$ of water and will spill over and also take out this dam having another $55km^3$ combided this is a substantial mass of water that will run into the ocean.

Will the release of these amounts of water affect the rotation of the earth?