Small, random questions about RotE that still bother you (spoilers all RotE books)

['thul]

being in a theoretical state of mind, 'thul has thought out a potential solution to the problem with channel size and depth of the RW river the further up it one goes.

Its been made clear that so long as the white current is part of it, the river is anything from mildly to highly acidic. It will quickly break down most materials, and it is quite possible it even breaks down rock. If it did not, then the rain wild traders would have imported stone to build things from near the shore, even if they would have to bring in vast shiploads of it to even set up lesser buildings. It is equally clear that it quickly eats through both wood and other lesser materials.
Thus the solution would be to have things made from materials impervious to the acid. There's far too little cocoon wood to make anything large enough to have any benefit with the problem here. The theory 'thul have is that there is one other building material that would not only be resistant, but possibly impervious to whatever the acid of the white current is. Memory stone.
The solution to making it possible for ships of decent size to pass up and down the river, while naturally also making it work for serpents would be to make a canal that is both deep and decently wide, either beside the river or within it, framed and walled with memory stone blocks. In theory such a channel could even be extended much further up the river than to Cassarick. Given enough stone supply, it could be built far enough up to reach the place where the current enters the river.
At its top end it would be natural to have wide-reaching walls out to the sides so as to catch more of the river. it would take years to build, but it would no doubt be worth it.

In looking at the theory now, it might even be easier to build it from the top down. The dragon quarries are in the mountains and it would be easier to ship the stone that way.
What do you think of this theory?