Hmmmm, I thought the Des Moines river might have a mayfly hatch but looks like it doesn't. Up here the Missouri has a weak hatch but on the other side of the state the Mississippi had a great hatch when my wife and I were there several years ago in July. We took a motel room in Gutenburg and there happened to be a great hatch. Big mayflies were everywhere and coated the ground. I had the best smallmouth fishing I ever had in my life with some walleye and catfish thrown into the mix. I have no idea if this a regular occurrence or not but one time I got lucky.

Do the walleye in Saylorville or any other of the reservoirs come in shallow in the fall or spring? They do in Spirit & Storm lake as well as some other places I know of.