I believe because it is a nature preserve. I remember walking off the trails to take a few pics, and one of the park rangers caught me and asked nicely for me to stay on the trail in order to protect the moss and grasses and different kind of plants. I imagine it is the same for going in the water, to protect it from any kind of contamination.
Yes nature perseverance along with liability for people becoming injured.
You cannot wade in the creeks and waterfall areas because of multiple reasons. You can't go off trail because of the cliffs and damage to ecosystem. But top would be that it is very damaging to a delicate gorge ecosystem (there are Federally endangered and threatened plants/animals in the water like Brooke Lamprey). Their homes, nests, and food sources are everywhere that you walk or wade. Even the oils, lotions, soaps from your body can kill them. Second, is safety. Rocks fall from the waterfalls above. Loose and crumbling rock in the water make for dangerous holes and unsafe footing. Multiple carryouts occur each year from injuries received in the water. There are 4-5 million people who visit the park. Folks come to the Hocking Hills to take in the beauty and do not want to see people jumping, swimming, and wading and destroying that beauty. There are many places you can visit that allow swimming/wading such as the nearby beach at Lake Logan or Lake Hope.
Safety and state park along with nature preserve
Cool I had a great time there with my family
Someone might have fallen was our reasoning.
Thanks! Your answer is awaiting moderation.