VI-232 



(4) Control of thermal pollution in coastal waters involves 

 the same kind of stratified flow problems as sewage disposal. 

 Inasmuch as large submerged diffusion structures are not in 

 use yet, some problems of large single jets need special 

 study, such as the behavior of a buoyant surface jet injected 

 in a stream perpendicular to the current. 



(5) Field studies of flow patterns and dilutions over waste 

 outfalls are needed urgently to confirm design predictions and 

 methods. Host of the hydrodynamics of buoyant jet mixing 



has been confirmed only in laboratory experiments. 



Physical Processes in Estuaries 



It is necessary to develop a sound physical basis for quantitative 

 predictive models of time and space variations of constituent distri- 

 butions in estuaries. This will require further work on theoretical, 

 numerical, and physical models, determining the correlation between 

 the models and field studies. Priorities need to be set based on 

 the urgency of the practical problem and the relative degree of under- 

 standing of the particular class of estuary. The most urgent problems 

 are likely to occur in those estuaries which we know the most about, 

 primarily coastal plain estuaries. 



(1) Further knowledge is required of the relationship of 

 the mean circulation, tidal currents, and turbulent 

 exchanges to the river inputs, external tides, external 

 density distribution, wind, and the shape and size of the 

 estuary. 



