The same shattering
When water breaks, it splits charge.
A wave breaks on a reef. A river breaks over a ledge. The water does the same thing in both places: it shatters into droplets and spray, and in the shattering it separates electric charge. The fine mist carries away negative charge; the heavier water keeps positive. The air near the base fills with negative ions.
This is measured, not imagined. Near large waterfalls the negative-ion count has been recorded in the tens of thousands per cubic centimeter — far above the few hundred of ordinary indoor air. The droplet-fracture mechanism behind it is the same balloelectric / spray-electrification effect studied since the nineteenth century, and the same that fills sea air with charge where surf breaks.
Kolarz et al. (2012): negative air-ion concentrations near waterfalls up to ~60,000 cm⁻³, roughly 120× indoor background (<500 cm⁻³).
Blanchard (1955): charge separation from bursting bubbles in breaking sea spray — the marine parallel.
What that charged air does to a person standing in it is a separate, honest question — the mood and restoration studies near moving water are real but confounded, and we don't pretend otherwise. The physics we can state plainly. The meaning we leave to you.
A handful you already know
The famous ones.
These are the waterfalls everyone can name — the ones on postcards and park signs, public to the last drop. They're a doorway, not the whole house.
A dozen of more than eleven thousand. Most have no postcard — they fall in steep country, off-trail, where the map runs out. The count is the point: the continent is louder than its famous edges.
The wave that comes in, the water that falls, the river's first source — one moving body, read from different edges.
Scale stated as a fact of nature. No site list, no coordinates, no map — the full catalog is a working research dataset, not a public directory. What's public here is the number and the physics.