Just water blockage won't have much or any effect.
India has been blocking Pakistans water for quite sometime and agriculture has moved away from relying on canal water.
Nah, turns out Pakistan is still 80% river dependent. 90% of food production comes out of river water.
Anyway, less water means less water in canals, making it easier to cross.
Plus this move will backfire as this may send Pakistan into so or die mindset, as water is a necessity of life.
Faster surrender.
Out of the two options, die thirsty because India is blocking our water, and die fighting with the aggressor who's intentions are to starve us , I rather take the later option.
Surrender, third option.