China has controlled paracel for 40 yrs and drilling area is right near triton island. Vietnam came all the way to cause trouble.
Cutting under water fiber optic is act of sabotage that has nothing to do with oil drilling.
Diverting some water won't make them all died. Just consider that as a dry season.
I think they should go further to team up with Cambodia and divert the Southern Mekong river going into Vietnam or build a Dam there.
economically sanction vietnam can come into many forms;
1)Withdraw all chinese investments from Vietnam
2)Freeze of vietnamese assets in China.
Finally, keep on persistent pressure. Vietnam is small country, yes they can put a fight but that would make them a nervous wreck psychologically and can't progress economically. No chance of being developed nation if CHina can keep up its pressure. They can fight all they want.
What do you mean they will not all die? You mean you are willing to sacrifices civilians? Be responsible when you mention things like that (although I know you are angry, but that do not give you the rights to take life - no matters whose lightly.)
As to cutting of optic fibre... do you or the Chinese had solid proof it was the Vietnamese who did that? Please note that not too distance history, the Chinese was also accused of cutting underwater cables belonging to Vietnam. So... does Vietnam start shooting into China? No? Why? Vietnam is weaker? If that is the reason, and China is stronger and China do as you proposed, doesn't that make the Chinese nothing but bullies?
economically sanction vietnam can come into many forms;
1)Withdraw all chinese investments from Vietnam
2)Freeze of vietnamese assets in China.
1) That would hurt China too. Chinese businessmen and companies in Vietnam invested quite a large sum of money, pulling those out would hurt normal Chinese citizen.
2) Freeze of Vietnamese assets in China - what have normal Vietnamese people who invested in China did wrong to China? In what law would the Chinese do that? And if the Chinese actually did that... then what guarantee would other foreigners who invested into China feel? They might just pull out... and worst... those that pull out still needed a place of production... so where can they go... Vietnam, Indonesia and Thailand (less of Thailand now until she stabilized). So in a sense, yeah, I hope China did that... then investment will come rolling into ASEAN.
Like I say before, you cannot look at things in a single angle. Many things are actually interlinked. Of course you can hammer Vietnam easily, whats with the current China's military might, you can do funny things to Vietnam's economy, you can even do as you claim, build a dam, let the Vietnamese die of thirst.
But internationally, who is going to pay? China... thats who.
I am so glad that the leader of China is not actually doing what you have said. They have display utmost maturity and responsibility and it is comforting.