You just truck the ingredients to the right spot and drop them into a 3d printer on tracks that works by continuously extruding pipeline.
Then if its a water pipeline on a slope somehow stick in an electrical generator every chance you get generate electricity.
The idea of extracting energy from the flowing water is novel. If the pipe is heading down slope all the way from it's source to it's destination it might work. If however, it has to climb hills as well as descend you may find the flow slows drastically and it requires a pump to keep it moving at the desired rate. (That is true even if you don't try to generate electricity.)
The Roman engineers built aqueducts from the mountains to their cities. When they encountered a valley, they built a bridge like structure supporting an open topped trough. The idea being to maintain the downward slope throughout the length of the aqueduct.
Regards,
GtG
When I talked about pipes —I meant really big pipes that carry water. They’re made of concrete.
Here’s a couple articles about portlands hydro electric pipes.
http://magazine.good.is/articles/portland-pipeline-water-turbine-power