Twin Falls, Rock Island State Park
Full listing: waterfallsforall.com/twin-falls
Rock Island sits right on Center Hill Lake's headwaters, which makes it the natural first stop for any guest. Twin Falls is the unusual one — water pours from openings in a limestone gorge wall rather than off a cliff edge — and Waterfalls For All confirms it's visible from the handicap-accessible parking lot on Powerhouse Road, with a further accessible walking trail leading to the Spring Castle stonework nearby.
Full view from the paved, handicap-accessible lot — no hike required. Wanting the base of the falls instead means the Downstream Trail, a real hike that isn't accessible.
An unusual, distinct sound signature — water audibly emerging from openings in rock rather than falling off an edge. The overlook and lot are level and paved underfoot.
A fully visual experience — the falls, the gorge wall, and the Spring Castle are all take-it-in-by-sight stops. No confirmed on-site interpretation; request one ahead for any ranger program.
Quiet countryside drive down Powerhouse Road. One thing to prepare a sensitive visitor for: TVA's dam releases are irregular and can raise water levels or sound a siren without warning — worth mentioning ahead of time so it isn't a surprise.