The Estuary Weir, or the Ocean Gate, is a large man-made structure built on Isle V3 to control the flow rate of the Lazy River, which flows through the Estuary Canyon. There is a large pillar-like structure, possibly natural, nearby that is dubbed the "Estuary Tower".
It is one of the most isolated human structures on the map, there is almost no flora and no lakes. Although the river is drinkable, it is also a very empty spot.