diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9bf1ec6..7f5ecd8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,7 +15,8 @@ It's about time I started a changelog! This will serve from now on as the main c
      - If you encounter any other issues with it over large areas (particularly 2000x150x2000 and larger), please let me know
  - Bugfix: Fix obscure crash in calls to `human_size` ("unknown" will now be returned if passed junk)
  - `//many` can now be used with commands with no arguments.
- - `//fillcaves`: Treat liquids as air when filling caves in
+ - `//conv`, `//erode`, `//fillcaves`: Treat liquids as air
+
 
 ## v1.10 (16th January 2021)
  - `//maze`: Fix some parts of generated mazes staying solid
diff --git a/worldeditadditions/utils/terrain.lua b/worldeditadditions/utils/terrain.lua
index 4032024..2875309 100644
--- a/worldeditadditions/utils/terrain.lua
+++ b/worldeditadditions/utils/terrain.lua
@@ -20,7 +20,7 @@ function worldeditadditions.make_heightmap(pos1, pos2, manip, area, data)
 			-- Scan each column top to bottom
 			for y = pos2.y+1, pos1.y, -1 do
 				local i = area:index(x, y, z)
-				if not worldeditadditions.is_airlike(data[i]) then
+				if not (worldeditadditions.is_airlike(data[i]) or worldeditadditions.is_liquidlike(data[i])) then
 					-- It's the first non-airlike node in this column
 					-- Start heightmap values from 1 (i.e. there's at least 1 node in the column)
 					heightmap[hi] = (y - pos1.y) + 1