I have found out over the years if I'm fishing rivers whether in Oklahoma or Arkansas and there's any current, you will be more successful on the downstream side of structure. Crappie doesn't like current so they will school up on the downstream side and feed on baitfish that come by. The structure will break the current enough for them to hold there. If you are fortunate enough to find structure in an eddy that's a bonus. Crappie use rivers for travel corridor's. Probably one of the most overlooked places to fish especially during pre-spawn and again in the fall.