I used to launch my drift boat at Beacon Rock, just below Bonneville Dam to fish for sturgeon. I've never fished for shad in that area, but when they're going over the dam by the millions, it would have to be good. I would find a spot next to shore in 15' to 20' of water, anchor, and drop a crappie spreader
to the bottom. I would run a shad dart and a small spoon like a triple teaser or dick nite off of the spreader...and hang on. Shad are strange though. I've found that moving the boat a few feet, or even changing the side of the boat you are fishing out of, can make all the difference in the world in your catch rate. They tend to follow a set path, and if you're in it, you hammer them. If you're not, you don't.

Take your sturgeon gear with you. A lot of people catch the shad only to use them as bait for the sturgeon.

Be sure you know what your doing when you anchor there. This is wicked water and boats are lost there every year. Have plenty of anchor rope, and don't tie it off directly to your boat. Most boaters use anchor pulling systems in this water and a line length of 7 to 10 times the depth they are anchoring in.