Deadeye96,
I'd not worry too much about snakes. If you've got enough time to pull a weapon out when you see one, you've got enough time to get/stay away from them. Taking care of a weapon that you constantly get wet is a time consuming task. It's not like in the movies where you come out of the water and things are magically okay with a little coat of oil. Several weapons can tolerate water pretty well, but it's not recommended you fire them while wet. It can be dangerous for several reasons.
Also, in Texas, carrying a weapon on a "navigable" river or waterway (not sure where you are on the Brazos..I grew up near that river myself) can be a big no-no. It can be considered firing a weapon in a public place if you shoot on the river. And if you don't have your CHL and are carrying a handgun...
My advice...keep you a nice walking stick close at hand. That'll keep the snakes at bay.
-SARguy