You probably can guess the post I'm referencing: http://www.reddit.com/r/todayilearned/comments/3ajdpr/til_the_han_dynasty_of_china_drilled_for_natural/
The wikipedia page cites The Genius of China: 3,000 Years of Science, Discovery, and Invention by Robert K. G. Temple. Is this a reliable source? Does he go into any further detail about these pipelines seeing as the wikipedia excerpt is just a just a few sentences.
You might find this interesting. Can't say I know much more than that, but I recall Needham mentioning the same thing in one of his books on China. You can download his books here if you're interested. Sorry for the short answer and I haven't read RKG's book, but this is something right? Maybe /u/Asiaexpert can help out.