Harry, the creek comes from a very large sump driven by two centrifugal pumps through two pipes in to three water sources (one pipe splits). Normally rainfall keeps the sump filled (and it handles overfill safely) but in this El Niño year I’ve to add water. We can hear the pumps when they start, but once the water gets going the natural noise going down the falls masks the mechanical sounds. All lovely, and controlled by apps on our phones. 😊