Arch,
There are several rivers that run into Lake Maurepas, which runs into Lake Ponchartrain. I spent whole summers in the Blind River, and The Lower Amite River when I was a teenager. I spent alot of time in False River too. When any of these south La. rivers or lakes are not real stirred up, and full of mud, then they are pretty clear, but full of pollen. Makes em real green. I have seen False River with vis to maybe 3' at best. I bet there is a TON of cool stuff on the bottom of False river. Probably alot of sunk small boats, as well as a millions sets of sunglasses and beer cans.
The local rivers are pure mud unless you go north to say, the Baton Rouge or Kentwood area where the Tangipahoa or Amite/Comite are clear, but VERY shallow. We ride our ATVs up and down them. There are the occasional deep holes, but not too often.
I guess the main problem is there is nothing deep. If you want to look at Bass in 10' of water, I have a 5 acre pond near my house, that is a clear as Ive seen around here, but it maxes out at about 12 feet. Good luck to you finding a good spot, but Im going to PCB this weekend!