Index: source/graphics/GameView.cpp
===================================================================
--- source/graphics/GameView.cpp
+++ source/graphics/GameView.cpp
@@ -581,7 +581,9 @@
 	const CVector3D nearPoint = position + forwards * m->ViewNear;
 	const CVector3D pivotPoint = position + forwards * m->Zoom.GetSmoothedValue();
 
-	const float ground = m->Game->GetWorld()->GetTerrain()->GetExactGroundLevel(nearPoint.X, nearPoint.Z);
+	const float ground = std::max(
+		m->Game->GetWorld()->GetTerrain()->GetExactGroundLevel(nearPoint.X, nearPoint.Z),
+		g_Renderer.GetWaterManager()->m_WaterHeight);
 
 	// filter ground levels for smooth camera movement
 	const float filtered_near_ground = m->Game->GetWorld()->GetTerrain()->GetFilteredGroundLevel(nearPoint.X, nearPoint.Z, near_radius);
Index: source/renderer/WaterManager.h
===================================================================
--- source/renderer/WaterManager.h
+++ source/renderer/WaterManager.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2012 Wildfire Games.
+/* Copyright (C) 2017 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -155,6 +155,11 @@
 	void UnloadWaterTextures();
 
 	/**
+	 * RecomputeWaterData: calculates all derived data from the waterheight
+	 */
+	void RecomputeWaterData();
+
+	/**
 	 * RecomputeWindStrength: calculates the intensity of waves
 	 */
 	void RecomputeWindStrength();
Index: source/renderer/WaterManager.cpp
===================================================================
--- source/renderer/WaterManager.cpp
+++ source/renderer/WaterManager.cpp
@@ -417,12 +417,14 @@
 // Calculate our binary heightmap from the terrain heightmap.
 void WaterManager::RecomputeDistanceHeightmap()
 {
+	CTerrain* terrain = g_Game->GetWorld()->GetTerrain();
+	if (!terrain || !terrain->GetHeightMap())
+		return;
+
 	size_t SideSize = m_MapSize*2;
 	if (m_DistanceHeightmap == NULL)
 		m_DistanceHeightmap = new float[SideSize*SideSize];
 
-	CTerrain* terrain = g_Game->GetWorld()->GetTerrain();
-
 	// Create a manhattan-distance heightmap.
 	// This is currently upsampled by a factor of 2 to get more precision
 	// This could be refined to only be done near the coast itself, but it's probably not necessary.
@@ -944,6 +946,9 @@
 // Calculate The blurred normal map to get an idea of where water ought to go.
 void WaterManager::RecomputeBlurredNormalMap()
 {
+	if (!g_Game->GetWorld()->GetTerrain()->GetHeightMap())
+		return;
+
 	// used to cache terrain normals since otherwise we'd recalculate them a lot (I'm blurring the "normal" map).
 	// this might be updated to actually cache in the terrain manager but that's not for now.
 	if (m_BlurredNormalMap == NULL)
@@ -997,6 +1002,17 @@
 	delete[] normals;
 }
 
+void WaterManager::RecomputeWaterData()
+{
+	if (!m_MapSize)
+		return;
+
+	RecomputeBlurredNormalMap();
+	RecomputeDistanceHeightmap();
+	RecomputeWindStrength();
+	CreateWaveMeshes();
+}
+
 ///////////////////////////////////////////////////////////////////
 // Calculate the strength of the wind at a given point on the map.
 // This is too slow and should support limited recomputation.
@@ -1006,6 +1022,9 @@
 		m_WindStrength = new float[m_MapSize*m_MapSize];
 
 	CTerrain* terrain = g_Game->GetWorld()->GetTerrain();
+	if (!terrain || !terrain->GetHeightMap())
+		return;
+
 	float waterLevel = m_WaterHeight;
 
 	CVector2D windDir = CVector2D(cos(m_WindAngle),sin(m_WindAngle));
Index: source/simulation2/components/CCmpTerrain.cpp
===================================================================
--- source/simulation2/components/CCmpTerrain.cpp
+++ source/simulation2/components/CCmpTerrain.cpp
@@ -146,10 +146,7 @@
 		if (ReloadWater && CRenderer::IsInitialised())
 		{
 			g_Renderer.GetWaterManager()->SetMapSize(vertices);
-			g_Renderer.GetWaterManager()->RecomputeBlurredNormalMap();
-			g_Renderer.GetWaterManager()->RecomputeDistanceHeightmap();
-			g_Renderer.GetWaterManager()->RecomputeWindStrength();
-			g_Renderer.GetWaterManager()->CreateWaveMeshes();
+			g_Renderer.GetWaterManager()->RecomputeWaterData();
 		}
 		MakeDirty(0, 0, tiles+1, tiles+1);
 	}
Index: source/simulation2/components/CCmpWaterManager.cpp
===================================================================
--- source/simulation2/components/CCmpWaterManager.cpp
+++ source/simulation2/components/CCmpWaterManager.cpp
@@ -67,6 +67,10 @@
 		Init(paramNode);
 
 		deserialize.NumberFixed_Unbounded("height", m_WaterHeight);
+
+		// Only update the graphical water height if it differs from the inital setting of the map
+		if (m_WaterHeight.ToFloat() != g_Renderer.GetWaterManager()->m_WaterHeight)
+			RecomputeWaterData();
 	}
 
 	virtual void HandleMessage(const CMessage& msg, bool UNUSED(global))
@@ -97,10 +101,8 @@
 	{
 		if (CRenderer::IsInitialised())
 		{
-			g_Renderer.GetWaterManager()->RecomputeBlurredNormalMap();
-			g_Renderer.GetWaterManager()->RecomputeDistanceHeightmap();
-			g_Renderer.GetWaterManager()->RecomputeWindStrength();
-			g_Renderer.GetWaterManager()->CreateWaveMeshes();
+			g_Renderer.GetWaterManager()->RecomputeWaterData();
+			g_Renderer.GetWaterManager()->m_WaterHeight = m_WaterHeight.ToFloat();
 		}
 
 		// Tell the terrain it'll need to recompute its cached render data
@@ -114,11 +116,7 @@
 
 		m_WaterHeight = h;
 
-		// Tell the terrain it'll need to recompute its cached render data
-		GetSimContext().GetTerrain().MakeDirty(RENDERDATA_UPDATE_VERTICES);
-
-		if (CRenderer::IsInitialised())
-			g_Renderer.GetWaterManager()->m_WaterHeight = h.ToFloat();
+		RecomputeWaterData();
 
 		CMessageWaterChanged msg;
 		GetSimContext().GetComponentManager().BroadcastMessage(msg);