This tank looks terrible-the zoo seems to have no AZA certificate. The tank looks barren and extremely minimalist. I hope this poor girl gets a better home soon.
Its possible this is a turtle with mobility issues and it needs to be kept in a small tank. Rehab facilities do keep recovering sea turtles in very small tanks to prevent them from expending energy and injuring themselves during recovery. Usually they will get released. But this place is a roadside in mid-America so Im not even sure how they'd wind up with such a turtle.