karson_
Lots of unmapped wing dams along a few mile stretch of the Mississippi here. 1930's aerial imagery was taken after construction of Dam 10, so they are already submerged and can't be traced from imagery. USACE charts show the wings, https://www.mvr.usace.army.mil/Missions/Navigation/Navigation-Charts/Upper-Mississippi-River/, you will need to align the image in JOSM and trace from the .pdfs.