Secret route from Garamsythe Waterway to Barhiem Passage

[charliebrown87]

yeah i already have everything i need to continue on in garamsythe... i even defeated the esper there... i was jus wondering where the passage to Barhiem was

[Dell]

East Sluice Gate. Southeastern-most area. I'm not sure about its name, though.
But you can't open it until you beat Zalera in Barheim Passage.