Repair crews are working on the concrete slab below the Gavins Point Spillway near Yankton.
The slab was damaged when record amounts of water were released during the 2011 flood of the Missouri River.
Photographer Nancy Tesdall took a picture of the icy conditions crews are working in earlier this month.
Project manager Dave Becker says crews have been removing ice from the spillway and some of it has been up to four feet thick.
Repairs on the slab started last winter. Becker expects the work will be done by the middle of February. After that, Becker says crews will focus on the 14 spillway gates.