Plant roots are amazing. Of course, they are moving and changing. But in such a long time scale that is basically imperceptible to us. Their ability to cross ‘arid’ areas to get to nourishment is baffling. Here they have been eroded by the humid southeastern US climate. But they continue to anchor and to go deeper.
No Swimming is good advice, since this is Alligator Lake. They also have signs saying “Don’t Feed the Gators”. Which is the same as no swimming.