--- a/src/newgrf_canal.cpp	Thu Sep 06 19:42:48 2007 +0000
+++ b/src/newgrf_canal.cpp	Sat Oct 06 21:16:00 2007 +0000
@@ -42,7 +42,7 @@
 
 	switch (variable) {
 		case 0x80:
-			return TileHeight(tile);
+			return GetTileZ(tile) / TILE_HEIGHT;
 
 		case 0x81:
 			return GetTerrainType(tile);