Just struck with some crazy idea. We know China is bringing heavy machinery in Galwan and stopping/damming the river to control the water flow according to its wish.
Also, we know China has amassed forces and build numerous camps across the valley.
How about we play their water games back upon them? How about we build a big dam on/after PP14, and stop the water flow there? Since the valley is narrow and water has no escape, it will rise and submerge the PP14 & subsequent Chinese positions. Chinese will, therefore, have to move back.
We can occupy the heights (which we already do) along PP14 to keep an eye and maintain our presence.
let me give you some idea of a river cross-section. The middle and deepest portion of a river, when viewed in cross-section, is called a thalweg. For a perennial or semi-perennial river, which is mostly mature (like the Ganges), the thalweg becomes smoother, shallower and blunt for downstream while it's mostly a gorge-like in upstream portions. Galwan River is one such semi-perennial river (it's mature too with all the braided sand deposits due to which a road could be built by its side) and its upstream is in the Chinese side of LAC.
All dams in the world are built upstream. If dams were built downstream, the downstream will get flooded first catastrophically due to the shallower thalweg without any significant rise of water levels in the deeper upstream region.
So, what you said
feels good but technicality will put this idea at a gross disadvantage.
By the way, if Chinese dam had indeed been destroyed by us, that means.....