Pitching (casting) blades can be done close to the dam if you know how to read the current breaks…casting a 1/4 oz blade such as a Heddon Sonar, BFT B3, or Silver Buddy hooked in the middle hole. Quarter upstream and slowly/gently pump the blade about 6″ off the bottom as it drifts downstream…maintaining a tight line by constantly reeling as you work the blade.
I use the same technique for pitching jigs/plastics below the Dam, but work it even slower.
I echo the time tested success of the jig/minnow…but have so much confidence in the blades/plastics that I no longer carry minnows…even when guiding…but that is up to you and until you have the confidence…bring some minnows! 
Mr. Ecklor is right! Move to downstream sand, gravel, clam beds or other current breaks and get away from the boat pressure. You may stick some big Piggies! 