diff -r 2c27f9be3fb9 -r f82a4facea8b src/water_cmd.cpp
--- a/src/water_cmd.cpp	Sat Oct 20 10:14:05 2007 +0000
+++ b/src/water_cmd.cpp	Sat Oct 20 10:42:28 2007 +0000
@@ -31,20 +31,21 @@
 #include "newgrf_canal.h"
 #include "misc/autoptr.hpp"
 
+/** Array for the shore sprites */
 static const SpriteID _water_shore_sprites[] = {
 	0,
-	SPR_SHORE_TILEH_1,
-	SPR_SHORE_TILEH_2,
-	SPR_SHORE_TILEH_3,
-	SPR_SHORE_TILEH_4,
+	SPR_SHORE_TILEH_1,  // SLOPE_W
+	SPR_SHORE_TILEH_2,  // SLOPE_S
+	SPR_SHORE_TILEH_3,  // SLOPE_SW
+	SPR_SHORE_TILEH_4,  // SLOPE_E
 	0,
-	SPR_SHORE_TILEH_6,
+	SPR_SHORE_TILEH_6,  // SLOPE_SE
 	0,
-	SPR_SHORE_TILEH_8,
-	SPR_SHORE_TILEH_9,
+	SPR_SHORE_TILEH_8,  // SLOPE_N
+	SPR_SHORE_TILEH_9,  // SLOPE_NW
 	0,
 	0,
-	SPR_SHORE_TILEH_12,
+	SPR_SHORE_TILEH_12, // SLOPE_NE
 	0,
 	0
 };
@@ -71,7 +72,7 @@
 
 	tile2 = tile + (axis == AXIS_X ? TileDiffXY(1, 0) : TileDiffXY(0, 1));
 
-	if (!IsClearWaterTile(tile) || !IsClearWaterTile(tile2))
+	if (!IsWaterTile(tile) || !IsWaterTile(tile2))
 		return_cmd_error(STR_3801_MUST_BE_BUILT_ON_WATER);
 
 	if (IsBridgeAbove(tile) || IsBridgeAbove(tile2)) return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
@@ -104,11 +105,11 @@
 
 	if (!IsShipDepot(tile)) return CMD_ERROR;
 	if (!CheckTileOwnership(tile)) return CMD_ERROR;
-	if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+	if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 	tile2 = GetOtherShipDepotTile(tile);
 
-	if (!EnsureNoVehicle(tile2)) return CMD_ERROR;
+	if (!EnsureNoVehicleOnGround(tile2)) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
 		/* Kill the depot, which is registered at the northernmost tile. Use that one */
@@ -171,7 +172,7 @@
 	if (!CheckTileOwnership(tile) && GetTileOwner(tile) != OWNER_NONE) return CMD_ERROR;
 
 	/* make sure no vehicle is on the tile. */
-	if (!EnsureNoVehicle(tile) || !EnsureNoVehicle(tile + delta) || !EnsureNoVehicle(tile - delta))
+	if (!EnsureNoVehicleOnGround(tile) || !EnsureNoVehicleOnGround(tile + delta) || !EnsureNoVehicleOnGround(tile - delta))
 		return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
@@ -302,7 +303,7 @@
 			}
 
 			/* Make sure no vehicle is on the tile */
-			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (GetTileOwner(tile) != OWNER_WATER && GetTileOwner(tile) != OWNER_NONE && !CheckTileOwnership(tile)) return CMD_ERROR;
 
@@ -313,7 +314,7 @@
 			Slope slope = GetTileSlope(tile, NULL);
 
 			/* Make sure no vehicle is on the tile */
-			if (!EnsureNoVehicle(tile)) return CMD_ERROR;
+			if (!EnsureNoVehicleOnGround(tile)) return CMD_ERROR;
 
 			if (flags & DC_EXEC) DoClearSquare(tile);
 			if (slope == SLOPE_N || slope == SLOPE_E || slope == SLOPE_S || slope == SLOPE_W) {
@@ -457,7 +458,7 @@
 	switch (GetWaterTileType(ti->tile)) {
 		case WATER_TILE_CLEAR:
 			DrawGroundSprite(SPR_FLAT_WATER_TILE, PAL_NONE);
-			if (ti->z != 0 || !IsTileOwner(ti->tile, OWNER_WATER)) DrawCanalWater(ti->tile);
+			if (IsCanal(ti->tile)) DrawCanalWater(ti->tile);
 			DrawBridgeMiddle(ti);
 			break;
 
@@ -517,7 +518,7 @@
 {
 	switch (GetWaterTileType(tile)) {
 		case WATER_TILE_CLEAR:
-			if (TilePixelHeight(tile) == 0 || IsTileOwner(tile, OWNER_WATER)) {
+			if (!IsCanal(tile)) {
 				td->str = STR_3804_WATER;
 			} else {
 				td->str = STR_LANDINFO_CANAL;
@@ -708,7 +709,12 @@
 	}
 }
 
-/** called from tunnelbridge_cmd, and by TileLoop_Industry() */
+/**
+ * Let a water tile floods its diagonal adjoining tiles
+ * called from tunnelbridge_cmd, and by TileLoop_Industry()
+ *
+ * @param tile the water/shore tile that floods
+ */
 void TileLoop_Water(TileIndex tile)
 {
 	static const TileIndexDiffC _tile_loop_offs_array[][5] = {
@@ -719,9 +725,12 @@
 		{{ 0, -1}, {0, 0}, {1, 0}, { 0, -1}, { 1, -1}}
 	};
 
-	/* Ensure sea-level canals and buoys on canal borders do not flood */
-	if ((IsTileType(tile, MP_WATER) || IsBuoyTile(tile)) && !IsTileOwner(tile, OWNER_WATER)) return;
+	/* Ensure buoys on canal borders do not flood */
+	if (IsCanalBuoyTile(tile)) return;
+	/* Ensure only sea and coast floods, not canals or rivers */
+	if (IsTileType(tile, MP_WATER) && !(IsSea(tile) || IsCoast(tile))) return;
 
+	/* floods in all four diagonal directions with the exception of the edges */
 	if (IS_INT_INSIDE(TileX(tile), 1, MapSizeX() - 3 + 1) &&
 			IS_INT_INSIDE(TileY(tile), 1, MapSizeY() - 3 + 1)) {
 		uint i;
@@ -730,6 +739,7 @@
 			TileLoopWaterHelper(tile, _tile_loop_offs_array[i]);
 		}
 	}
+
 	/* _current_player can be changed by TileLoopWaterHelper.. reset it back here */
 	_current_player = OWNER_NONE;
 
@@ -807,7 +817,7 @@
 static CommandCost TerraformTile_Water(TileIndex tile, uint32 flags, uint z_new, Slope tileh_new)
 {
 	/* Canals can't be terraformed */
-	if (IsClearWaterTile(tile) && IsCanal(tile)) return_cmd_error(STR_MUST_DEMOLISH_CANAL_FIRST);
+	if (IsWaterTile(tile) && IsCanal(tile)) return_cmd_error(STR_MUST_DEMOLISH_CANAL_FIRST);
 
 	return DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 }