I use to fish the Channel edge for Catfish where there was lots of scattered limbs on the bottom but there were not any Log piles that I have found -- you would think that somewhere there is a jam... Think about that sharp bend below A bridge.. All the Current blasts out of the bend and over what would have been the Bank of the old River Bed. The Flat behind the bend would be Devastated, Taking any Silt build up off leaving sand and hard bottom. It could be possible , Where the Current goes back into the channel downstream, a Build up where it enters, rolling those limbs and logs over the edge into deep water.