That was me. That's kinda my back garden (where we build things for testing then knock them down when we're done). It's noisy when we're trying to work stuff out. There's plenty of open space on the map, does it have to be in my back garden?
It's just a simple thing that opens gates letting water out in a wave-ish sequence. It's just a cart going back and forth on a track pushing buttons which temporarily close gates to cause the effect :) simple stuffs