When a reservoir is used to store water for electricity, it's pipes are usually laid in several segments on the ground to reach its source, such as a lake. It seems that if the pipes went directly to the lake by being suspended, less piping could be used and less energy lost due to friction would occur. Why are systems not built like this?
Suspended pipes are heavy and need support - any change of direction also creates a force - and there is the aerial impediment to consider : Birds, parachutes planes etc.
Also some "pipes" are cut directly into the rock saving on material costs and consider that some of these pipes have a water flow rate of 45m3/s so the inertial forces are massive.