Will the Russians link their clay together with a series of underground canals? Will the Chinese? Why/why not?

Reminder: the Romans built a 100km stretch of underground canal under mountains

https://en.m.wikipedia.org/wiki/Gadara_Aqueduct

https://en.m.wikipedia.org/wiki/List_of_longest_tunnels

Why wasn’t this kinda thing built years ago? It’s like, how much harder is it to dig a tunnel than a canal? A tunnel is prolly only like 2x as tall as a canal is deep anyway. It’s like, why /wouldn’t/ you?

It wouldn’t even silt up like a canal.