Answer:
Salt wedge
Step-by-step explanation:
"An estuary that is found within the mouth of a river where freshwater flows out to sea at the surface while seawater flows upstream along the bottom is a Salt wedge."
Salt-wedge estuaries take place when a rapidly moving river joins the ocean from the point of weak tidal currents. In such kind of salt estuary, the force of a river is responsible for pushing the water out to sea rather than upwards and is also a factor that determines the circular motion