salt-wedge | fjord | slightly stratified | vertically mixed | freshwater
A vertically mixed or well-mixed estuary occurs when river flow is low and tidally generated currents are moderate to strong (Ross, 1995). The salinity of water in a vertically mixed estuary is the same from the water's surface to the bottom of the estuary. Strong tidal currents eliminate the vertical layering of fresh water floating above denser seawater, and salinity is typically determined by the daily tidal stage. The estuary's salinity is highest nearest the ocean and decreases as one moves up the river. This type of water circulation is often found in large, shallow estuaries, such as Delaware Bay.