138 



water withdrawal only partially simulates the sea level rise effect, since 

 reduced runoff does not influence tides as significantly as does an 

 increased water depth. 



9.2 LITERATURE REVIEW 



The significance of salt water penetration has been a matter of common 

 knowledge among scientists and engineers for a long time, but the entire 

 process was placed on a firm physical footing relatively recently. Perhaps 

 the most important work, at least in the United States, was carried out 

 during the post-second world war period by Keulegan at the National Bureau 

 of Standards, by Ippen at M.I.T., and later by Harleman also at M.I.T., in 

 cooperation with the U.S. Army Engineer Waterways Experiment Station at 

 Vicksburg, Mississippi. These works, summarized in Ippen (1966), were 

 primarily laboratory-based, and sought to understand the intrusion process 

 through the development of basic, analytic formulations. It is noteworthy 

 that, in a sense, these investigations were successors to the pioneering 

 work of O'Brien (O'Brien and Cherno, 1934), which dealt with the 

 fundamentally similar problem of predicting the rate at which salt water 

 intrudes into fresh water, as in a lock separating a saline water body from 

 one of lower salinity. Partheniades (1971) has reviewed the fundamentals 

 of the salt water intrusion mechanisms (see also Partheniades et al., 

 1975). Beginning in 1954, the Committee on Tidal Hydraulics of the Corps 

 of Engineers has issued a series of reports pertaining to various 

 theoretical and practical aspects of the estuarine salinity intrusion 

 problem. 



Concurrently with the aforementioned basic laboratory- analytic 

 studies, physical models of real estuaries were developed, with the 

 inclusion of saltwater intrusion effects. The Corps of Engineers led this 

 effort, and constructed a rather large model of the San Francisco Bay 

 estuarine system in Sausalito, California (Fischer et al., 1979). This is 

 a distorted model (scales 1000 horizontally and 100 vertically), i.e., one 

 in which the water depths are greater than the linear scale set by the 

 aerial (horizontal) dimensions. Distortion is commonly employed in 

 physical models in order to generate sufficient turbulence necessary to 

 satisfy the desired equivalence between model and prototype flow 



