Comment by thinkcontext

The largest such effort is China's South - North Water Transfer Project, look into that if you are interested in the subject. Its unbelievably gigantic in scale, yet the amount of water moved is relatively modest compared to the amount of consumption.

https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Tran...

California is also an enormous plumbing project, much has been written on it.