Prior to 1950, studies of estuaries were primarily observational. Rhodes (1950), for instance, described velocities and salinities in several estuaries along the eastern coast of the United States. Stommel & Farmer (1952) compiled data from 20 worldwide estuaries, ranging in size from the Moros in France (2.3 km long and a few meters deep) to the Straits of Juan de Fuca (100 km long and 350 m deep). Their report, although more than 20 years old, remains one of the more extensive compilations of salinity and velocity data in existence and, in addition, shows the wide range of water bodies we call estuaries. Since the appearance in the early 1950s of Ketchum’s work (1951a,b, 1955), of the unpublished manuscript On the Nature of Estuarine Circulation by Stommel & Farmer (1952), and of Pritchard’s analyses of the salt balance in the James (1952 and later), researchers have used more analytic techniques to try to understand the process of mixing in estuaries and to quantify such aspects as residence times and pollutant concentrations.
via Fischer, 1976, Mixing and Dispersion in Estuaries, Annual Review of Fluid Mechanics
Stommel and Farmer, 1952, On the nature of estuarine circulation