I used to live in Fort Dodge and fished the Des Moines a lot. I have put in below the dam/spillway in Boone and fished up to the dam and have caught northerns and walleye in the Fall and Winter tossing jig and minnow combos. Most of my fishing was wading above Fort Dodge and mostly in the Fall. I had days where i caught 70+ smallmouth in an evenig after work. I would also catch walleyes, catfish, and northerns while fishing for the smallmouth. I caught all the fish on rapalas, cranks, mepps, and jigs, with white being the best color for the jig.
It was a totally under-used fishery when i was there in the early to mid ’90’s. I would often times be the only person on the river for several days in a row! Every once and a while a canoe would go by. I never saw any boats by Boone while i fished in the winter months.
Hope this helps. I do remember someone saying that there is a large hole upstream from Boone that holds a lot of fish in the winter. Never really looked for it though.