The Urist McMoses screw pump dam on the brook in the south-east corner of the map says "Frozen Elsewhere" on all components, despite the thaw having been a week ago in-game.

Prior to the thaw the water wheel was what was frozen, and when I noticed that all components still complained of frost I deconstructed and reconstructed it. I de/reconstructed no other components, especially not the left gear assembly in the southern pair due to it being attached to the lever next to the water wheel.

I did send a team of Urists McNoobsPumpOperators out to play with the screw pumps, but that did not kickstart the dam.