Not sure if the flooding brings in more crappie that makes the fishing better or the fact that the majority of the flooding occurs in the spring,ie. spawn time which inundates the buckbrush along shore and provides alot of cover for fry to hide in thus increasing numbers.I figure you are right about the rough fish and catfish coming from the river. Anouther thing about alot of these oxbows is that unless the river is at flood stage alot of them can't be accessed.just my 2cts.
3GD