This waterfall is beside my yard. When it's running, I know my water tanks are full and the spring is not dry.

Also it's computer controlled, for times when I don't want to hear it. I'll also use the computer control later on to avoid running the pump excessively and wearing it out, and for some safety features like not running when the water is frozen.

This is a whole hillside of pipes, water tanks, pumps, solar panels, all controlled by a GPIO port. Easy enough; the pump controller has a float switch input and the GPIO drives a 4n35 optoisolator to open or close that circuit. Hard part will be burying all the cable to the pump. And then all the landscaping around the waterfall.

There's a bit of lag to turning it on and off. It can take over an hour for it to start flowing, and around half an hour to stop. The water level has to get high enough in the water tanks to overcome some airlocks and complicated hydrodynamic flow stuff. Then when it stops, all that excess water has to drain back down.

Anyway, enjoy my soothing afternoon project and/or massive rube goldberg machine, I certainly am.