Block water by filling back in a ramp?

I would like to partially fill back in a moat I dug around my fortress walls and that involuntarily filled with water. Is there a way?

I have tried the following:

• build a wall connected to a floor at level z+1
• remove the floor.

The wall falls as expected right to level z-1 (the level of the ramp) but it does not fill it.

Solution 1:

Constructed walls deconstruct when they fall, only a wall made from solidified magma wouldn't. You would need to build a wall in the flooded location. but before you can do that the water needs to be removed. Probably the easiest way is to dig a drain to the edge of the map one Z level below, then dig up into that spot. A screw pump could also remove water long enough to build the wall, but those can be kind of messy.