I have been fishing the river around Muscatine for walleye for almost five years, and I still haven’t figured out their summer patterns. I catch a lot of walleye and sauger in the spring and fall below Lock and Dam 16, so I know they are in there in the summer…somehere…biting on something…
Problem is, I have not figured out how to catch them consistently down here in the summer months. I have twenty-plus years’ experience catching walleye on Pools 5a through 8 in the summer, and I can pound them up there consistently this time of year. When I try the tactics (wingdams with crawler harnesses, leeches, willow cats, crankbaits, floating plugs on three-way rigs) that work up around Lacrosse and Winona in Muscatine, I get all the sheepshead, channel cat, mudcat, etc. I could want, but not many walleye or sauger. Could anyone tell me what I am doing wrong? 
I must have caught twenty-five of them today. No walleye, but I did pick up a sauger off a clam bed. A couple of eater channel cats showed up on my rigs, too. Channel edges produced sheepshead, as did the front of the wing dams and the clam bed. I was fishing the upper end of the pool, but with fairly low and falling water levels I might have been better off on the lower end of a pool–that is the rule of thumb I have found.