CGW
The land on either side of the river belongs to someone. That may be a private land owner, State of Fla/Water Management District, or whoever. If you do not have official authorization to be on that property, you could be arrested for Trespass.
If you are arrested for trespass and have a weapon, that is a third degree felony. A felony conviction will ruin your life forever.
Don't risk it.
Dave