Alexander's Hetaroi
Deity
My mistake, flood barrier was mentioned on the official site. Not sure why my mind was thinking of a flood gate.Aaaaaaaaaaaaaaah! Terminology guys!
A floodgate is a gate, typically in a river, though it can also be found in canals and the like, which can be opened to change water levels; this causes a flood in the lower areas, hence it's name. They're also very common (if not always present) with dams to allow for better control of the water level in the reservoir.