[Huliwang]

Using thousands of drones to blast the dam is a good idea but can drones fly 1300 km from Taiwan to the three gorges dam? I think the max distance drone can only do aroud 10 km  currently........
Even if the attack is successful with 1000 drones, at most it will cause a dent or a small leak which is not disastrous. 

Further, attacking the dam can killed 400 million civilians if it really collapsed is a crime against humanity which will  justify the Chinese to invade Taiwan which can be achieved within 72-hours where the culprit of the dam attack will be hunted down. 
In such situation no allies will stand with Taiwan and that's for sure.......