Looking at the photos below, I believe it isn’t lake Gnostos, but the same shore as the Genie washed up at (that would be King Leopold’s kingdom). Maybe also the shore in front of Charming’s castle.
http://storybrooke.net/photos/displayimage.php?album=178&pid=20968#top_display_media
http://storybrooke.net/photos/displayimage.php?album=178&pid=20970#top_display_media
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