I haven't had a chance to fish for walleyes at Dale yet (can't get away from the smallies), but from what I've heard, February and March are the best months and the places to fish are up the Obey and the Wolf river. If you fish the Obey, check the regulations as I believe there's a restriction for a single hook (no trebles) in the eastern fork during the spring spawn.
As far as the summer goes, I believe most walleye fisherman troll crank baits and lindy rigs at night in the flats on the main lake in 20+ ft.
Sorry that I can't speak from experience.