Not many bluebacks around in August, unless you're in tidewater, or better yet, the bay (sea runs and Chinook usually go hand-in-hand). There will be plenty of nice resident cuts, though. Any coastal stream will have plenty. If I had to pick one, I'd go with the mainstem Nehalem (haven't checked the regs, but it also gets a very small run of summer Chinook, but don't tell anyone).