/* Create additional river tiles around possible lock locations to connect them. */
	for (uint tile = 0; tile != MapSize(); tile++) {
		if (IsValidTile(tile) && IsTileType(tile, MP_WATER) && IsRiver(tile) && IsInclinedSlope(GetTileSlope(tile))) {

			Slope slope = GetTileSlope(tile);
			DiagDirection dir = GetInclinedSlopeDirection(slope);
			int delta_side = TileOffsByDiagDir(ChangeDiagDir(dir, DIAGDIRDIFF_90RIGHT));
			int delta_mid = TileOffsByDiagDir(dir);

			TileIndex tile_upper_centre = tile + 2 * delta_mid;
			TileIndex tile_upper_right = tile + delta_mid + delta_side;
			TileIndex tile_upper_left = tile + delta_mid - delta_side;
			TileIndex tile_upper_upper = IsWaterTile(tile_upper_centre) ? INVALID_TILE : tile_upper_centre;
			TileIndex tile_upper_upper_right = IsWaterTile(tile_upper_right) ? tile_upper_centre + delta_side : INVALID_TILE;
			TileIndex tile_upper_upper_left = IsWaterTile(tile_upper_left) ? tile_upper_centre - delta_side : INVALID_TILE;

			TileIndex tile_lower_centre = tile - 2 * delta_mid;
			TileIndex tile_lower_right = tile - delta_mid + delta_side;
			TileIndex tile_lower_left = tile - delta_mid - delta_side;
			TileIndex tile_lower_lower = IsWaterTile(tile_lower_centre) ? INVALID_TILE : tile_lower_centre;
			TileIndex tile_lower_lower_right = IsWaterTile(tile_lower_right) ? tile_lower_centre + delta_side : INVALID_TILE;
			TileIndex tile_lower_lower_left = IsWaterTile(tile_lower_left) ? tile_lower_centre - delta_side : INVALID_TILE;

			TileIndex tiles[] = {tile_upper_upper, tile_upper_upper_right, tile_upper_upper_left, tile_lower_lower, tile_lower_lower_right, tile_lower_lower_left};
			for (int i = 0; i < lengthof(tiles); i++) {
				if (tiles[i] != INVALID_TILE && IsTileFlat(tiles[i])) {
					assert(!IsWaterTile(tiles[i]));
					MakeRiver(tiles[i], Random());
					/* Remove desert directly around the river tile. */
					CircularTileSearch(&tiles[i], 5, RiverModifyDesertZone, NULL);
				}
			}
		}
	}