I grew in a swamp a few yrs back and what I did was found a few stumps that were hollowed out and sat my 5 gallon buckets down in the stumps.
And don't use the swamp water to water your grow. The only downside I had was the humidity causing mold and bud rot.
But after sorting out the moldy and rotting buds I ended up with about 1 3/4lbs of good bud after harvest and drying.
Personaly I will never grow in that area again because of this problem. But yes it can be done...take care..