A salt wedge estuary is a highly stratified estuarine type in which river discharge dominates over tidal mixing, resulting in a distinct, wedge-shaped intrusion of denser saline water along the bottom extending upstream beneath a layer of less dense, relatively fresh river water flowing seaward at the surface; this configuration produces a strong halocline (sharp vertical salinity gradient) separating the two layers, with minimal vertical mixing between them, and a net seaward flow dominating at the surface.