diff --git a/Source/PolygonalMapGenerator/Private/IslandMap.cpp b/Source/PolygonalMapGenerator/Private/IslandMap.cpp
index 9455469..a024172 100644
--- a/Source/PolygonalMapGenerator/Private/IslandMap.cpp
+++ b/Source/PolygonalMapGenerator/Private/IslandMap.cpp
@@ -159,6 +159,9 @@ void AIslandMap::GenerateIsland_Implementation()
 #endif
 
 	// Reset all arrays
+	CreatedRivers.Empty(NumRivers);
+	spring_t.Empty();
+	river_t.Empty(NumRivers);
 
 	r_water.Empty(Mesh->NumRegions);
 	r_water.SetNumZeroed(Mesh->NumRegions);
diff --git a/Source/PolygonalMapGenerator/Private/Rivers/IslandRivers.cpp b/Source/PolygonalMapGenerator/Private/Rivers/IslandRivers.cpp
index 0d0390f..4df16f1 100644
--- a/Source/PolygonalMapGenerator/Private/Rivers/IslandRivers.cpp
+++ b/Source/PolygonalMapGenerator/Private/Rivers/IslandRivers.cpp
@@ -165,6 +165,7 @@ void UIslandRivers::AssignSideFlow_Implementation(TArray<int32>& s_flow, TArray<
 {
 	if (Mesh)
 	{
+		Rivers.Empty(river_t.Num());
 		s_flow.Empty(Mesh->NumSides);
 		s_flow.SetNumZeroed(Mesh->NumSides);
 		TMap<FTriangleIndex, URiver*> riverTriangles;