How do I fill a downward slope in Dwarf Fortress?
I was trying to make an upward slope level and used Channel on it, but that turned it into a downward slope. How do I 'fill' the downward slope so that it becomes level with the ground?
You can build-Construct a floor over it, or a wall on the level below. In the future, if you want to get rid of upward ramps, designate them with zRemove upward ramps/stairs, rather than channeling them.