diff --git a/mods/default/mapgen.lua b/mods/default/mapgen.lua
index 016d58de59fe67a99944eefd5f932829750a1ebe..c84aa7b42e35031c710c9add809df708866466ca 100644
--- a/mods/default/mapgen.lua
+++ b/mods/default/mapgen.lua
@@ -334,6 +334,8 @@ function default.register_biomes()
 		depth_water_top = 10,
 		--node_water = "",
 		node_river_water = "default:ice",
+		node_riverbed = "default:gravel",
+		depth_riverbed = 2,
 		y_min = -8,
 		y_max = 31000,
 		heat_point = 0,
@@ -372,6 +374,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:gravel",
+		depth_riverbed = 2,
 		y_min = 2,
 		y_max = 31000,
 		heat_point = 15,
@@ -390,6 +394,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:gravel",
+		depth_riverbed = 2,
 		y_min = -3,
 		y_max = 1,
 		heat_point = 15,
@@ -408,6 +414,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:gravel",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = -4,
 		heat_point = 15,
@@ -427,6 +435,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 2,
 		y_max = 31000,
 		heat_point = 15,
@@ -445,6 +455,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = 1,
 		heat_point = 15,
@@ -465,6 +477,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 6,
 		y_max = 31000,
 		heat_point = 40,
@@ -483,6 +497,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 5,
 		y_max = 5,
 		heat_point = 40,
@@ -501,6 +517,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = 4,
 		heat_point = 40,
@@ -520,6 +538,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 6,
 		y_max = 31000,
 		heat_point = 40,
@@ -538,6 +558,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 5,
 		y_max = 5,
 		heat_point = 40,
@@ -556,6 +578,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = 4,
 		heat_point = 40,
@@ -575,6 +599,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 6,
 		y_max = 31000,
 		heat_point = 60,
@@ -593,6 +619,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 5,
 		y_max = 5,
 		heat_point = 60,
@@ -611,6 +639,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = 4,
 		heat_point = 60,
@@ -630,6 +660,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 1,
 		y_max = 31000,
 		heat_point = 60,
@@ -648,6 +680,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -3,
 		y_max = 0,
 		heat_point = 60,
@@ -666,6 +700,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = -4,
 		heat_point = 60,
@@ -686,6 +722,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 5,
 		y_max = 31000,
 		heat_point = 85,
@@ -704,6 +742,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = 4,
 		heat_point = 85,
@@ -723,6 +763,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 1,
 		y_max = 31000,
 		heat_point = 85,
@@ -741,6 +783,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -3,
 		y_max = 0,
 		heat_point = 85,
@@ -759,6 +803,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = -4,
 		heat_point = 85,
@@ -778,6 +824,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = 1,
 		y_max = 31000,
 		heat_point = 85,
@@ -796,6 +844,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -3,
 		y_max = 0,
 		heat_point = 85,
@@ -814,6 +864,8 @@ function default.register_biomes()
 		--depth_water_top = ,
 		--node_water = "",
 		--node_river_water = "",
+		node_riverbed = "default:sand",
+		depth_riverbed = 2,
 		y_min = -112,
 		y_max = -4,
 		heat_point = 85,