diff --git a/biomes.lua b/biomes.lua
index 25a35ed..fb9c90a 100644
--- a/biomes.lua
+++ b/biomes.lua
@@ -9,7 +9,7 @@ local function register_biome(enabled, def)
 	def.node_dungeon_alt = def.node_dungeon and "" or "default:mossycobble"
 	def.node_dungeon_stair = def.node_dungeon_stair or "stairs:stair_cobble"
 
-	if def.y_min > 0 and def.node_riverbed == nil then
+	if def.y_max > 0 and def.node_riverbed == nil then
 		def.node_riverbed = "default:sand" ; def.depth_riverbed = 2
 	end