I do not have much experience in walleye fishing around there, only caught a couple here and there. I am not sure what they mean by mud bottom, but it is all gravel bottom from the dam down. In fact there is a gravel plant about 2 miles down and they come up stream close to the dam to get gravel sometimes. There have been quite a few people who catch walleye below the dam. My guess would be to concentrate on up stream of deeper holes where it meets the riffles, and bounce a 1/4 jig or larger and minnow combo to get down to the bottom and keep it vertical. Whites are abundant and should be running soon, hit the fast water for them around structure and up stream from deep hole where riffles meet. When the dam is generating water then the fishing can be good, when no generation I would focus more downstream in the areas with current. I do not have a boat and have only fished that area out of a boat once, so my experience is limited that way. But I have fished the bank up near the dam for a long time, have done well on whites and hybrids when they are running and the dam is generating water. Hope this helps a little.