An estuary in which, at any given location, wind or tidal mixing homogenizes salinity throughout the water column.

In a vertically homogeneous estuary the river flow is weak, and the tidal flow is strong. Consequently, no stratification occurs, and salt water may even move up the river channel. Salinity levels are nearly the same from top to bottom at any given place in such estuaries; however, the salinity is lowest where the river enters the estuary and highest near the sea.