The Pinaisara Falls in Iriomote-Ishigaki National Park boast the largest drop (about 55 meters) in Okinawa, and the surrounding area has a wide variety of natural environments such as subtropical laurel forests, low-lying swamp areas, mangrove forests, and tidal flats. It has been nominated as a World Natural Heritage site candidate. In recent years, however, concerns have arisen about the deterioration of the natural environment caused by “human waste” around the waterfall due to the large number of visitors.
The Iriomote Ranger Office of the Environment Ministry and the Iriomote Island Canoe Association have been working together to test the use of portable toilets in order to preserve the natural environment around the Pinaisara Falls.