Permaculture in Brackish Water

I am interested in creating a permaculture system in a tricky spot. That is, a friend of mine currently own 17 acres of retired golf course Geneva, Florida (zone 9) on a lake front. The whole property is covered in grass and contains all together about six ponds that are stocked with tilapia and crawfish. The property is also double fenced in, which doesn't do much as bobcats always find a way in. Yet the tricky part is that there is an annual flood of brackish water (~3% salt content) that covers most of the usable land and lasts for about two weeks. They have tried growing some crops, tomatoes, basil, citrus, potatoes, etc. with no success. Looking into salt tolerant vegetables and fruit trees, there arent many options. Any suggestions on how to develop the property to become a productive/profitable permaculture system? Anyone that can point me to a farm with a similar problem? Any crop suggestions? I dont think they are interested in making it pasture, too many predators.

Howdy Jake, welcome to permies!

Could they dig a trench (moat) all the way around, use the soil to make a large hugel bed all the way around, just inside the trench (moat) , and stop the flooding?

A big problem is the land flooding for two weeks a year, whether or not the water is brackish. The flooding alone will drastically limit what you can grow, so finding a way to raise the grade of some garden spots, or to "polder" some or most of the land as suggested above, might be the only option. There are some plants tolerant of somewhat saline soil (asparagus and the beet family come first to mind), but they will not endure flooding or poor drainage for long. Provided you mound up, and have plenty of rain, the salt should leach downwards permitting more sensitive plants to grow.

Hi,

Have you read/seen much about Chinampas? If not, essentially they are raised beds developed by the Aztec, developed specifically to deal with the problem that you are dealing with in this spot, I've linked a video that may help

Have you looked into seaberries / seabuckthorn?
They are able to tolerate the salt. But I doubt they will fair well with the flooding.
I'd definitely work on raising the ground level up a bit.

We are working on raising the ground a bit, and I've recently found a study showing that biochar can absorb salts because of its high CEC.