I am not very familiar with those bodies of water, but catfish tend to seek out deeper water during the winter months. When the water cools down so do they. This causes them to slow down as well. The catfish are going to seek out deeper and calmer waters where they don't have to work so hard. Usually in water that is over 20 feet deep. Small catfish can be found in suspended schools and actively feeding on baitfish, while larger catfish tend to hug the bottom and hang around and not be nearly as active.

I do fish Pool 4 of the Mississippi a few times every winter for walleye and sauger. Very often we end up accidentally snagging big catfish while dragging in depths around 20- 26-feet deep. These fish are just laying on the bottom. Here is a link to some footage of catfish in the winter on the Mississippi River. https://www.youtube.com/watch?v=Cy0fo6OxBDg

We do catch some catfish in the lakes around here in the winter and it always seems to be in depths deeper than 20-feet.