salt wedge estuary

A salt wedge estuary is a type of estuary where freshwater from a river meets and mixes with saltwater from the ocean. In this specific type of estuary, the river's outflow is the dominant force, and tidal influences are minimal.1

The freshwater floats on top of the denser saltwater, forming a distinct layer. This creates a wedge-shaped body of seawater underneath the freshwater layer, which thins out as it moves inland. The boundary between the freshwater and saltwater is clearly defined, with very little mixing occurring between the two. The mouth of the Mississippi River is a classic example of a salt wedge estuary. This circulation pattern, where surface water moves toward the sea and deeper water moves inland, helps to transport nutrients, supporting significant biological productivity within the estuary.12