You'll been fine in your boat around Lyons Ferry and above the dam. The current in the main river is very strong when the gates are open on the dam. You can call the dam hotline and found out what the flows are. But the flows don't really matter if you launch from the state park and head up the Palouse. When you head into that area with a boat you want to fish along the bluffs, out in front of them, in the river channel, and in the bay at the park.