This an entirely wrong approach to tackle this problem.
As they say, "An Eye for an Eye makes the world a blind man."
China, India and Bangladesh should get into negotiations on this .... and come up with something as elegant as this:
Indus Waters Treaty - Wikipedia, the free encyclopedia
Despite all differences, India and Pakistan worked this out and it lasts even half a century after it was signed.
Even though China has publicly denied plans to divert any water .... it's better to have a treaty.
Simply, because it boosts trust.
I know, the so called people who claim themselves to be "official" representatives of China on this forum have a different agenda ..... gleeing at the potential of harming others. It comes back, in form or the other.
Good, that their words don't matter.