John Berry: Fishing High Water in Arkansas
At this water level, the fish are in side channels or over weed beds. They are deeper, and the current is greater. Therefore I use a longer and a stronger tippet (3X or 4X) and larger flies. You want the trout to be able to see them.
I also use a lot more lead to make sure that the fly ticks the bottom. To float this increased weight, I use the largest strike indicators that I can find. Once again you cast out from the boat and drift the fly with the boat. The secret is to set up the boat so that you will float by the weed beds at the proper distance for you to present your flies to the fish.
Read the article complete with high water fly selections via the Baxter Bulletin.